CN118414562A

CN118414562A - Wire grid polarizing element, method for producing wire grid polarizing element, projection display device, vehicle, and photocurable acrylic resin for imprinting

Info

Publication number: CN118414562A
Application number: CN202280083979.6A
Authority: CN
Inventors: 佐佐木浩司; 中西大地; 中泽裕
Original assignee: Dexerials Corp
Current assignee: Dexerials Corp
Priority date: 2021-12-24
Filing date: 2022-12-26
Publication date: 2024-07-30
Also published as: CN118414563A

Abstract

The invention provides a wire grid polarizer which has excellent heat dissipation and excellent transmittance and polarization separation characteristics for oblique incident light with a wide incident angle. A wire grid polarizing element (1) is provided with: a substrate (10) made of an inorganic material, a grid structure (20) formed integrally with a plurality of raised strips (22) in a base portion (21) made of an organic material and provided on the substrate (10), and a functional film (30) made of a metal material and covering a part of the raised strips (22). The ridge portion (22) has a head-thin shape that narrows in width as it moves away from the base portion (21). The functional film (30) wraps the tops of the raised strips (22) and does not cover the bottom sides of the raised strips (22) and the base portion (21). The coating rate (Rc) of the side surface of the raised strip (22) coated by the functional film (30) is 30-70%. The organic material is a cured product of an acrylic resin curable for imprinting containing a photopolymerizable component.

Description

Wire grid polarizing element, method for producing wire grid polarizing element, projection display device, vehicle, and photocurable acrylic resin for imprinting

Technical Field

The present invention relates to a wire grid polarizing element having excellent polarization characteristics, which is free from deterioration in heat radiation and cost during production, and which is excellent in transmittance for incident light from an oblique direction and incident light at a wide range of incident angles, a method for producing the wire grid polarizing element, a projection display device having excellent polarization characteristics and heat resistance, a vehicle equipped with the projection display device, and an imprint photocurable acrylic resin.

Background

As one of the projection display devices, a number of in-vehicle head-up display devices have been developed in recent years, which display images on a semi-transmissive panel (hereinafter, collectively referred to as "display surface") such as a windshield, a combination panel, or the like of a vehicle. The in-vehicle head-up display device is, for example, an image display device that is disposed in an instrument panel of a vehicle, projects image light onto a windshield, and displays driving information as a virtual image. Since the driver can see the virtual image and the landscape transmitted through the windshield at the same time, there is an advantage that the movement of the driver's line of sight is small compared with a conventional display device such as a liquid crystal display provided outside the range of the windshield.

However, in the head-up display device described above, since the display image is projected from the lower side (upper side) of the windshield, sunlight may be incident on the display element in a direction opposite to the direction of projection of the display image. In many head-up display devices, reflectors for reflecting and enlarging a display image are provided for the purpose of downsizing and enlarging the display image. In this case, sunlight entering the head-up display device is concentrated near the display element, and there is a possibility that the display element may be degraded or malfunction due to heat.

Accordingly, a technique of providing a reflective polarizing element in a head-up display device has been developed for the purpose of preventing sunlight from entering a display element. For example, patent document 1 discloses a head-up display device in which a reflective polarizing element (wire grid polarizing plate) is provided between a reflector and a display element.

Examples of the polarizing element provided in the head-up display device include a polarizing element made of a birefringent resin, a wire grid type polarizing element in which a plurality of conductors (thin metal wires) extend in parallel on a transparent substrate, and a polarizing element made of cholesteric liquid crystal. Among them, wire grid type polarizing elements excellent in polarization characteristics are often used. In the wire grid type polarizing element, a wire grid is formed in which conductor wires made of metal or the like are arranged in a grid shape at a specific pitch. By setting the arrangement pitch of the wire grid to a pitch smaller than the wavelength of incident light (for example, visible light) (for example, a pitch of 2 times or less), light of an electric field vector component vibrating parallel to the conductor wire can be reflected almost and light of an electric field vector component perpendicular to the conductor wire can be transmitted almost. As a result, the wire grid polarizer can be used as a polarizer that generates single polarization, and can reflect and reuse light that is not transmitted, and thus is also expected from the viewpoint of efficient use of light. The polarizing element referred to herein includes a polarizing element that can be used as a polarizing beam splitter that separates incident light into S-polarized light and P-polarized light.

As such a wire grid type polarizing element, for example, patent document 2 discloses a wire grid type polarizing element including: the wire grid polarized light plate comprises a resin substrate having grid-shaped protrusions, a dielectric layer provided so as to cover the grid-shaped protrusions of the resin substrate, and metal wires provided on the dielectric layer.

Patent document 3 discloses a wire grid polarized light plate having a substrate made of resin or the like and having a surface provided with a concave-convex structure extending in a specific direction and an electric conductor provided so as to be offset to one side surface of a convex portion of the concave-convex structure. In this wire grid polarized light plate, the pitch, i.e., the interval between two adjacent protrusions and the height of the protrusions can be adjusted in a cross-sectional view in a direction perpendicular to the extending direction of the concave-convex structure.

Patent document 4 discloses a projection type image display device using a reflective liquid crystal display element and a reflective linear grating polarizing plate as polarizing beam splitters. In the projection type image display device using the reflective liquid crystal display element described in patent document 4, the reflective linear grating polarization plate is disposed at an inclination of 45 ° with respect to the optical axis of the light emitted from the light source. The outgoing light from the light source enters at an incident angle inclined by 45 ° with respect to the reflection-type linear grating, thereby being separated into first polarized light (reflected light) and second polarized light (transmitted light). Then, the first polarized light reflected by the reflective type linear grating polarization plate is modulated and reflected by the reflective type liquid crystal display element, and becomes second polarized light, and the second polarized light passes through the reflective type linear grating polarization plate to be projected and displayed.

Further, patent document 5 discloses a vehicle-mounted headlamp using a reflective wire-grid polarizing plate as a polarizing beam splitter. In the vehicle-mounted headlamp described in patent document 5, the reflective wire-grid polarizing plate is disposed at an inclination of 45 ° with respect to the optical axis of the light emitted from the light source. The light emitted from the light source enters at an incidence angle of 45 ° inclined to the reflection type linear grating, and is separated into first polarized light (reflected light) and second polarized light (transmitted light).

In the projection type image display device described in patent document 4 and the vehicle-mounted headlamp described in patent document 5, when the reflective type linear polarization plate is disposed at an angle of 45 ° with respect to the light emitted from the light source, the incident light is incident at an angle of incidence ranging from 45 ° ± 15 ° with respect to the reflective type linear polarization plate, in addition to a single angle of incidence of 45 °.

Patent document 6 discloses a wire grid polarization beam splitter in which a plurality of grids made of silver or aluminum are formed on a substrate in a protruding manner.

Patent document 7 discloses a wire grid type polarized photon including a light transmissive substrate, a base layer, and fine metal wires. In the wire grid type polarized photon of patent document 7, a plurality of convex strips are formed on the surface of a light-transmitting substrate at predetermined pitches in parallel with each other. The base layer is composed of a metal oxide at least on top of the ridge, and the fine metal wire is composed of a metal layer on the surface of the base layer and at least on top of the ridge.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open No. 2018-72507

Patent document 2: japanese patent laid-open No. 2008-83657

Patent document 3: japanese patent application laid-open No. 2017-173832

Patent document 4: japanese patent laid-open No. 2004-184889

Patent document 5: japanese patent application laid-open No. 2019-50134

Patent document 6: japanese patent laid-open No. 2003-508813

Patent document 7: international publication No. 2010/005059

Disclosure of Invention

Problems to be solved by the invention

In addition, the temperature environment required for equipment used in vehicles is typically-40 to 105 ℃, and particularly when used in a high temperature environment such as a head-up display mounted on an instrument panel in a summer crown block, high heat resistance and heat dissipation are required. In this regard, the wire grid polarizing plates described in patent documents 1 to 3 are required to be further improved in heat resistance and heat dissipation. In order to illuminate a night road with the vehicle-mounted headlamp described in patent document 5, it is necessary to increase the brightness of the vehicle-mounted headlamp. Therefore, the wire grid polarized light plate described in patent document 5 is required to have high heat resistance and heat dissipation to heat from the light source.

In addition, since the surface roughness of the conventional wire grid polarizer is generally formed by photolithography and etching, there is also a problem that the manufacturing cost increases and mass production is not suitable.

In a projection display device such as a head-up display device, when a reflective linear grating polarization element is used as a polarization beam splitter to separate the light into a first polarized light (S polarized light) and a second polarized light (P polarized light), it is required that both the reflectance of the first polarized light and the transmittance of the second polarized light are high. Here, when the product (tp×rs) of the reflectance (Rs) of the first polarized light (S polarized light) and the transmittance (Tp) of the second polarized light (P polarized light) is used as an index of the polarization separation characteristic, the higher value of tp×rs is preferable. However, the processing of polarized light in the polarizing beam splitter may be different depending on the type of projection display device to which the polarizing beam splitter is applied, and the first polarized light (S polarized light) may be transmitted light and the second polarized light (P polarized light) may be reflected light.

Further, the incident angle of the incident light with respect to the polarization beam splitter is not only a single angle of 45 °, but also expands within a range of about 45±15° centered on 45 °, and light of a wide range of incident angles is incident to the polarization beam splitter. Therefore, it is also required that the polarization beam splitter can exhibit good polarization separation characteristics for oblique incident light regardless of the incident angle of the incident light (hereinafter referred to as oblique incident light) from an oblique direction.

However, in the case of the conventional structure of the reflective linear grating polarization element, as the incident angle of oblique incident light increases, there is a problem that the transmission axis transmittance (Tp) of second polarized light (P polarized light) decreases, and the polarization separation characteristic with respect to oblique incident light decreases. For example, consider a case where the entire protruding portion of the grid is constituted by an electric conductor as described in patent document 6, and an electric conductor (reflective film) is provided so as to be offset to one side surface of the protruding portion of the wire grid as described in patent document 3. In these cases, as the incident angle of oblique incident light increases, the transmission axis transmittance (Tp) of the second polarized light (P polarized light) decreases, resulting in a decrease in tp×rs described above. Therefore, the efficiency of light utilization is deteriorated, and the image quality such as uneven brightness is deteriorated. Accordingly, in the conventional structures of the reflective wire grid polarizer described in patent documents 3 and 6, there is room for improvement in polarization separation characteristics with respect to oblique incident light having a wide range of incident angles.

Patent document 7 describes that the coating ratio of the side surface of the ridge covered with the metal layer (reflective film) is preferably 50% or more and 70% or more, and particularly preferably 100%. Patent document 7 describes that when the area of the metal layer covering the side surfaces of the convex strips is enlarged, it is possible to achieve a lower S-polarized light reflectance with respect to light incident from the back surface side of the wire grid-type polarized photon, and it is possible to effectively reflect S-polarized light incident from the front surface side, thereby exhibiting high polarization separation energy of the wire grid-type polarized photon.

However, when the area of the metal layer covering the side surfaces of the ribs of the wire grid is wide as described in patent document 7, the transmittance (Tp) of the second polarization light (P polarization light) is greatly reduced when the incidence angle of oblique incident light is large, particularly 45 to 60 °, and thus tp×rs is also greatly reduced. Therefore, the efficiency of light utilization is deteriorated, and the image quality such as uneven brightness is deteriorated. Therefore, even in the structure of the wire grid type polarized photon described in patent document 7, there is room for improvement in polarization separation characteristics with respect to oblique incident light having a wide range of incident angles.

As described above, it is expected to have excellent polarization separation characteristics with respect to oblique incident light having a wide range of incidence angles, but in the conventional reflective wire grid polarizer, sufficient transmittance with respect to light having a wide range of incidence angles, particularly, a large incidence angle of 45 ° or more, cannot be ensured, and further improvement in transmittance and polarization separation characteristics with respect to oblique incident light is expected.

The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a wire grid polarizing element excellent in heat radiation and excellent in transmittance and polarization separation characteristics of oblique incident light with respect to a wide range of incident angles, a method for manufacturing the polarizing element, a projection display device and a vehicle each including the polarizing element, and an imprint photocurable acrylic resin.

Means for solving the problems

The present inventors have made intensive studies to solve the above problems, and as a result, have found the following findings. First, a substrate of the wire grid polarizing element is formed of a transparent inorganic material and a grid structure provided on the substrate is integrally formed of a transparent organic material. Thus, the wire grid polarizer can have a hybrid structure composed of an organic material and an inorganic material. As a result, the heat dissipation of the wire grid polarizer can be significantly improved.

As the grid structure, a grid structure in which a base portion provided along a surface of a substrate and a plurality of ridge portions protruding from the base portion are integrally formed is used. Thus, the grid structure can be formed by a technique such as nanoimprint, and therefore, the manufacturing cost of the grid structure can be reduced, and mass production can be achieved, as compared with the case of using a photolithography technique or an etching technique.

When a functional film such as a reflective film for reflecting light or an absorptive film for absorbing light is provided on the ridge portions of the grid structure, the coating range and coating form of the ridge portions coated with the functional film are appropriately adjusted. That is, the distal ends of the ridge portions and the upper sides of the side surfaces on one side or both sides are covered with the functional film, while the lower sides of the side surfaces of the ridge portions and the surfaces of the base portion are not covered with the functional film and are opened. The functional film has an arc and is formed to cover the tip ends of the raised strips and the upper side of the side surfaces in such a shape that the functional film bulges in the width direction of the raised strips. The shapes and sizes of the raised strips and the functional films are adjusted so that the maximum width (W _MAX) of the grid formed by the raised strips and the functional films wrapping the raised strips is equal to or greater than the width (W _B) of the bottoms of the raised strips. Further, the range of the side surface of the functional film coating ridge portion is preferably limited to a specific range on the upper side of the side surface (for example, a range of 25% to 80% of the height (H) of the ridge portion).

Thus, even when oblique incident light having a large incident angle and a wide range is incident on the wire grid polarizing element, the transmittance (Tp) of the second polarized light (P polarized light) in the wire grid polarizing element can be suppressed from decreasing depending on the incident angle. Therefore, the product (tp×rs) of the reflection axis reflectance (Rs) of the first polarized light (S polarized light) and the transmission axis transmittance (Tp) of the second polarized light (P polarized light) in the wire grid polarizing element can be maintained at a high value. Thus, even when the wire grid polarizing element is used as a polarizing beam splitter, for example, sufficient transmittance and polarization separation characteristics can be obtained for oblique incident light having a large incident angle and a wide range.

The present inventors have conceived the following inventions based on the above findings.

In order to solve the above-described problems, according to one aspect of the present invention, there is provided a wire grid polarizing element including:

A substrate made of an inorganic material;

a grid structure body formed of an organic material and having a base portion provided on the substrate and a plurality of ridge portions protruding from the base portion integrally formed; and

A functional film made of a metal material and covering a part of the ridge portion,

The ridge portion has a head-thin shape whose width becomes narrower as it is away from the base portion,

The functional film wraps the front end of the raised strip part and the upper side of at least one side surface, and does not wrap the lower side of the two side surfaces of the raised strip part and the base part,

When the coating ratio (Rc) of the side surface of the ridge portion coated with the functional film is a ratio of the height (Hx) of the portion coated with the functional film to the height (H) of the ridge portion, the coating ratio (Rc) is 30% to 70%,

The organic material is a cured product of an acrylic resin curable for imprinting containing a photopolymerizable component,

The photopolymerizable component comprises:

A resin (A); and

A resin (B),

The resin (A) is (octahydro-4, 7-methylene-1H-indene-1, 5 subunit) bis (methylene) diacrylate,

The resin (B) is a difunctional acrylate monomer having a viscosity of 10 mPas or less at 25 ℃,

The content of the resin (A) is 20 to 40 mass% based on the entire photopolymerization component,

The total content of the resin (A) and the resin (B) is 70 mass% or less relative to the entire photopolymerizable component.

The viscosity of the photocurable acrylic resin for imprinting at 25 ℃ may be 35mpa·s or less.

It is also possible to use a method in which,

The photopolymerizable component further comprises a resin (C),

The resin (C) is an acrylate monomer having a viscosity of 10 mPas or less at 25 ℃,

The total content of the resin (B) and the resin (C) is 50 mass% or more and 70 mass% or less with respect to the entire photopolymerizable component.

It is also possible to employ such a manner that the resin (C) is a monofunctional acrylate monomer.

The resin (C) may be isobornyl acrylate.

It is also possible to use a method in which,

The photopolymerizable component further comprises a resin (D),

The resin (D) is a trifunctional or higher acrylate monomer,

The content of the resin (D) relative to the entire photopolymerizable component is more than 0 mass% and 20 mass% or less.

It is also possible to employ a mode in which the resin (D) is one or more selected from the group consisting of trimethylolpropane triacrylate, dipentaerythritol hexaacrylate, and multifunctional polyester acrylate.

The resin (B) may be a difunctional acrylate monomer bonded to an acryl group at each of both ends of a linear structure composed of a hydrocarbon group or a difunctional acrylate monomer bonded to an acryl group at each of both ends of a linear structure having an ether bond.

It is also possible to use a method in which,

The resin (B) is a difunctional acrylate monomer represented by the following chemical formula (I), wherein n is an integer of 1 to 9.

CH ₂＝CHCOO(CH ₂)_nOOCCH＝CH ₂…(I)

In the chemical formula (I), n may be an integer of 6 to 9.

In the chemical formula (I), n is 6 or 9.

It is also possible to use a method in which,

After the cured product of the photocurable acrylic resin for imprinting was kept at 120℃for 500 hours,

The YI value of the cured product is 3 or less.

It is also possible to use a method in which,

The cured product of the photocurable acrylic resin for imprinting has a storage modulus of 1.6X10 ⁹ Pa or more at 30 ℃,

The storage modulus of the cured product at 120 ℃ is 3.9X10 ⁸ Pa or more.

It is also possible to use a method in which,

The cured product has an average transmittance of 91% or more with respect to light in a wavelength region of 430nm to 680nm,

The cured product has an average transmittance of 90% or more with respect to light in a wavelength region of 430nm to 510 nm.

It is also possible to use a method in which,

The photocurable acrylic resin for imprinting further contains a photopolymerization initiator for polymerizing the photopolymerization component.

The surface of the functional film wrapping the raised strips is provided with an arc, and bulges in the width direction of the raised strips,

The maximum width (W _MAX) of the functional film wrapping the ridge may be equal to or greater than the width (W _B) of the ridge at a position 20% above the height of the ridge from the bottom of the ridge, the portion not being wrapped by the functional film.

The convex structure formed by the convex strip and the functional film may have a cross-sectional shape of a whole, and a narrowed portion having a width narrowed in a width direction of the whole convex structure may be provided at a position immediately below a lower end portion of the functional film surrounding the convex strip.

The product (tp×rs) of the transmission axis transmittance (Tp) and the reflection axis reflectance (Rs) of the incident light having an incident angle of 45 ° with respect to the wire grid polarizing element may be 70% or more.

The height (H) of the raised lines may be 160nm or more.

The thickness (Dt) of the functional film covering the tips of the raised strips may be 5nm or more.

The functional film covering the side surfaces of the raised strips may have a thickness (Ds) of 10nm to 30 nm.

The Thickness (TB) of the base portion may be 1nm or more.

The cross-sectional shape of the ridge portion in the cross-section orthogonal to the reflection axis of the wire grid polarizing element may be a trapezoid, triangle, bell, or oval shape whose width becomes narrower as it is away from the base portion.

The functional film may be formed so as to cover at least the surface of the functional film.

The protective film may contain a water-repellent coating or an oil-repellent coating.

The functional film may further include a dielectric film.

In the case where θ is 30 ° to 60 °,

The difference between the transmission axis transmittance (Tp (+)) of the incident light having an incident angle of +θ with respect to the wire grid polarizing element and the transmission axis transmittance (Tp (-)) of the incident light having an incident angle of- θ may be 3% or less.

The functional film may be a reflective film that reflects incident light.

The wire grid polarizing element may also be a polarizing beamsplitter that separates obliquely incident light into first and second polarized light.

In order to solve the above-described problems, according to another aspect of the present invention, there is provided a method for manufacturing a wire grid polarizing element, including:

Forming a grid structure material made of an organic material on a substrate made of an inorganic material;

Forming a grid structure integrally formed by a base portion provided on the substrate and a plurality of ridge portions protruding from the base portion by nanoimprinting on the grid structure material; and

A step of forming a functional film covering a part of the ridge portion by using a metal material,

In the step of forming the grid structure, the raised line part having a head-thin shape which narrows in width with distance from the base part is formed,

In the step of forming the functional film,

The functional film is formed so that the coating ratio (Rc) of the side surfaces of the raised strips coated by the functional film is 30% to 70% when the coating ratio (Rc) of the side surfaces of the raised strips coated by the functional film is the ratio of the height (Hx) of the portion coated by the functional film to the height (H) of the raised strips, and the functional film is coated on the top of at least one side surface of the raised strips, and the lower side of the side surfaces of the raised strips and the base portion are not coated.

The photopolymerizable component comprises:

A resin (A); and

A resin (B),

In the step of forming the functional film, the film may be formed alternately on the ridge portions from a plurality of directions by sputtering or vapor deposition.

In order to solve the above problems, according to another aspect of the present invention, there is provided a projection display device including:

A light source;

a polarization beam splitter configured to make incident light from the light source incident at a prescribed range of incidence angles including 45 ° and split the incident light into first polarized light and second polarized light;

a reflective liquid crystal display element configured to be incident with the first polarized light reflected by the polarizing beam splitter or the second polarized light transmitted through the polarizing beam splitter, and reflect and modulate the incident first polarized light or second polarized light; and

A lens configured to make the first polarized light or the second polarized light reflected and modulated by the reflective liquid crystal display element incident through the polarizing beam splitter,

The polarizing beam splitter is comprised of the wire grid polarizing element.

The incidence angle in the predetermined range may be 30 ° or more and 60 ° or less.

A heat sink member may be provided around the wire grid polarizing element.

In order to solve the above problems, according to another aspect of the present invention, there is provided a vehicle including the projection display device.

In order to solve the above-mentioned problems, according to another aspect of the present invention, there is provided an imprinting photocurable acrylic resin which is used for the wire grid polarizing element and contains a photopolymerization component, wherein,

The photopolymerizable component comprises:

A resin (A); and

A resin (B),

Effects of the invention

According to the present invention, a wire grid polarizing element having excellent heat radiation properties and excellent polarization separation characteristics with respect to oblique incident light having a wide range of incident angles can be provided.

Drawings

Fig. 1 is a cross-sectional view schematically showing a wire grid polarizing element according to an embodiment of the present invention.

Fig. 2 is a plan view schematically showing the wire grid polarizing element according to the embodiment.

Fig. 3 is a cross-sectional view schematically showing a specific example of the head shape of the ridge portion of the grid structure according to this embodiment.

Fig. 4 is a cross-sectional view schematically showing a specific example of the shape of the concave portion of the grid structure according to the embodiment.

Fig. 5 is a cross-sectional view schematically showing a wire grid polarizing element according to this embodiment.

Fig. 6 is a cross-sectional view schematically showing a specific example of the shape of the reflection film according to this embodiment.

Fig. 7 is a cross-sectional view schematically showing a polarizing element covered with the protective film according to this embodiment.

Fig. 8 is a cross-sectional view schematically showing a modification of the polarizing element covered with the protective film according to the embodiment.

Fig. 9 is a perspective view schematically showing a polarizing element including a heat radiating member according to this embodiment.

Fig. 10 is a photograph showing an actual grid structure and a reflective film according to this embodiment.

Fig. 11 is a process diagram showing a method for manufacturing a wire grid polarizer according to this embodiment.

Fig. 12 is a process diagram showing a conventional method for manufacturing a wire grid polarizer.

Fig. 13 is a process diagram showing a method for manufacturing a master according to this embodiment.

Fig. 14 is a schematic view showing a head-up display device which is an example of the projection display device according to the embodiment.

Fig. 15 is a schematic view showing a first specific example of the projection display device according to the embodiment.

Fig. 16 is a schematic diagram showing a second specific example of the projection display device according to the embodiment.

Fig. 17 is a schematic diagram showing a third specific example of the projection display device according to the embodiment.

Fig. 18 is a diagram for explaining a polarizing element according to conventional example 1.

Fig. 19 is a diagram for explaining a polarizing element according to conventional example 2.

Fig. 20 is a diagram for explaining a polarizing element according to conventional example 3.

Fig. 21 is a diagram for explaining a polarizing element according to example 1.

Fig. 22 is a diagram for explaining the comparison result between example 1 and conventional example 2.

Fig. 23 is a diagram for explaining a polarizing element according to example 2.

Fig. 24 is a diagram for explaining a polarizing element according to example 3.

Fig. 25 is a diagram for explaining a polarizing element according to example 4.

Fig. 26 is a diagram for explaining a polarizing element according to example 5.

Fig. 27 is a diagram for explaining a polarizing element according to example 6.

Fig. 28 is a diagram for explaining a polarizing element according to example 7.

Fig. 29 is a diagram for explaining a polarizing element according to example 8.

Fig. 30 is a diagram for explaining the comparison result between example 9 and conventional example 4.

Fig. 31 is a diagram for explaining the comparison result between example 9 and conventional example 4.

FIG. 32 is a graph showing the relationship between wavelength and luminosity function (Luminosity function).

Detailed Description

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the present specification and drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and overlapping description thereof is omitted. For convenience of explanation, the states of the respective members disclosed in the following drawings are schematically illustrated in a scale and a shape different from the actual ones.

<1 > Outline of wire grid polarizing element

First, an outline of the wire grid polarizer 1 according to an embodiment of the present invention will be described with reference to fig. 1,2, and the like. Fig. 1 is a cross-sectional view schematically showing a wire grid polarizer 1 according to the present embodiment. Fig. 2 is a plan view schematically showing the wire grid polarizer 1 according to the present embodiment.

The wire grid polarizer 1 according to the present embodiment is a reflective polarizer and is a wire grid polarizer. The wire grid polarizing element 1 may be, for example, a plate-shaped wire grid polarizing plate. The wire grid polarizing plate is a wire grid polarizing plate having a plate shape. The wire grid polarizing plate may be, for example, a flat plate or a curved plate. That is, the surface (light incident surface) of the wire grid polarizing element 1 may be a flat surface or a curved surface. The wire grid polarizing element 1 according to the present embodiment is described below as an example of a flat plate-shaped wire grid polarizing plate, but the wire grid polarizing element of the present invention is not limited to the example, and may have any shape depending on its application, function, and the like.

The wire grid polarizing element of the present invention may be used, for example, as a polarized photon that transmits only light vibrating in a specific one direction, or may be used as a polarizing beam splitter that splits incident light into first polarized light (S polarized light) and second polarized light (P polarized light). The wire grid polarizing element 1 according to the present embodiment will be mainly described below as an example of a polarizing beam splitter.

As shown in fig. 1 and 2, the wire grid polarizer 1 (hereinafter, sometimes simply referred to as "polarizer 1") includes a transparent substrate 10, a transparent grid structure 20, and an opaque functional film (e.g., a reflective film 30).

In the present specification, "transparent" means that the transmittance of light of wavelength λ to which a wavelength band (for example, a wavelength band of visible light, a wavelength band of infrared light, or a wavelength band of visible light and infrared light) belongs is high, and the transmittance of the light is 70% or more, for example. The wavelength band of visible light is, for example, 360nm to 830 nm. The wavelength band of infrared light (infrared) is greater than that of visible light, for example, 830nm or more. The wavelength λ of the use band in the polarizing element 1 according to the present embodiment is, for example, preferably 400nm to 800nm, more preferably 420nm to 680nm, from the viewpoint of an appropriate wavelength range of visible light projected as a display image. Since the polarizing element 1 according to the present embodiment is formed of a material transparent to light in the use wavelength band, the polarizing characteristics, light transmittance, and the like of the polarizing element 1 are not adversely affected.

The substrate 10 is made of a transparent inorganic material such as glass. The substrate 10 is a flat plate-like substrate having a predetermined thickness TS.

The grid structure 20 is made of a transparent organic material, for example, an organic resin material such as an ultraviolet curable resin or a thermosetting resin having excellent heat resistance. The grid structure 20 has a concave-convex structure for realizing the polarized light function of the polarizing element 1. Specifically, the grid structure 20 has: a base portion 21 provided along the surface of the substrate 10, and a plurality of ridge portions 22 protruding in a lattice shape from the base portion 21. The base portion 21 and the plurality of raised strips 22 of the grid structure 20 are integrally formed using the same organic material.

The base portion 21 is a film having a predetermined thickness TB, and is integrally laminated on the main surface (XY plane shown in fig. 1 and 2) of the substrate 10. The thickness TB of the base portion 21 is preferably substantially the same thickness on the entire main surface of the substrate 10, but may not be entirely the same thickness, and may vary with a certain degree of error with respect to the reference thickness of TB. For example, TB may vary by + -3 μm from the reference thickness of 6 μm. In this way, molding errors in molding the base portion 21 are allowed by embossing or the like, and the thickness TB of the base portion 21 is determined.

The plurality of raised strips 22 are arranged at equal intervals in the X direction on the base 21 at a predetermined pitch P. The pitch P is a formation interval of the plurality of ridge portions 22 arranged in the X direction of the polarizing element 1. The plurality of raised strips 22 are arranged in a grid shape so as to extend parallel to each other and to be raised in the Y direction. A predetermined gap is formed between two raised strips 22 adjacent to each other in the X direction. The gap becomes an entrance path for incident light. Each of the raised strips 22 is a wall-shaped convex portion formed so as to extend in a predetermined direction (Y direction shown in fig. 1 and 2) in a slender manner. The height (H) in the Z direction and the width (W _T、W _B) in the X direction of the plurality of raised strips 22 are substantially the same as each other. The longitudinal direction (Y direction) of the ridge portion 22 is the direction of the reflection axis of the polarizing element 1, and the width direction (X direction) of the ridge portion 22 is the direction of the transmission axis of the polarizing element 1.

The functional film is a film for imparting a predetermined function to the grid structure 20 of the polarizing element 1. The functional film is made of, for example, an opaque metal material, and is provided so as to cover a part of the ridge portions 22 of the grid structure 20. The functional film may be, for example, a reflective film 30 having a function of reflecting incident light entering the polarizing element 1, or an absorbing film (not shown) having a function of absorbing the incident light, or a film having another function. In the present embodiment, an example in which the functional film is the reflective film 30 is described, but the functional film of the present invention is not limited to the example of the reflective film 30.

The reflective film 30 is a thin film made of a metal material (metal or metal oxide, etc.) such as aluminum or silver. The reflective film 30 is formed so as to cover at least the top of the ridge portion 22. The reflective film 30 may be formed of a metal film functioning as a wire grid of metal thin wires. The reflection film 30 has a function of reflecting incident light that enters the grid structure 20.

The ridge portions 22 of the grid structure 20 and the reflective film 30 constitute a grid of the wire grid polarizing element 1. The pitch P in the X direction of the plurality of raised strips 22 (i.e., the arrangement pitch of the grids) in the grid structure 20 is set to be smaller than the wavelength λ of the incident light (e.g., visible light) (e.g., 2 times smaller). Thus, the polarizing element 1 can reflect almost the light (S polarized light) of the electric field vector component vibrating in the direction (reflection axis: Y direction) parallel to the reflective film 30 (conductor line) extending upward in the Y direction, and transmit almost the light (P polarized light) of the electric field vector component vibrating in the direction (transmission axis: X direction) perpendicular to the reflective film 30 (conductor line).

As described above, the wire grid polarizing element 1 according to the present embodiment realizes the polarized light function by the combination of the grid structure 20 having the fine uneven structure and the functional film (for example, the reflective film 30) selectively provided to the convex portions 22 of the grid structure 20. The substrate 10 of the wire grid polarizer 1 is made of an inorganic material such as glass having excellent heat resistance, and the grid structure 20 is made of an organic resin material having heat resistance. As described above, the wire grid polarizer 1 according to the present embodiment is a hybrid polarizer in which an organic material and an inorganic material are combined. Therefore, heat can be efficiently dissipated from the grid structure 20 having a small thermal resistance R [ m ². K/W ] to the substrate 10, and therefore heat dissipation is excellent. Therefore, the hybrid wire grid polarizer 1 according to the present embodiment is superior to a conventional film-type polarizer (heat resistance: 100 ℃ C.) composed only of an organic material in heat resistance and heat dissipation, for example, in a high-temperature environment up to 200 ℃ C. This can realize excellent polarization characteristics and maintain a good heat dissipation effect.

The wire grid polarizing element 1 according to the present embodiment may further include a protective film 40 (see fig. 7 and 8) covering the surface of the grid structure 20. The protective film 40 is made of an inorganic material, for example, a dielectric material such as SiO ₂. The protective film 40 is laminated on the entire surface of the linear polarization element 1 so as to cover all surfaces of the base portion 21, the ridge portion 22, and the reflective film 30 of the grid structure 20 (see fig. 7). By providing the protective film 40, the heat resistance R of the polarizing element 1 can be further reduced, and thus excellent polarization characteristics can be achieved and a better heat dissipation effect can be maintained.

As described above, the grid structure 20 in which the base portion 21 and the ridge portions 22 are integrally formed can be manufactured by a printing technique such as nanoimprint, and therefore, a fine uneven structure can be realized in a simple manufacturing process. Therefore, the cost and effort required for manufacturing the grid structure 20 can be reduced as compared with the case of manufacturing by using the photolithography technique or the etching technique. As a result, the hybrid-type polarizing element 1 according to the present embodiment has an advantage that the manufacturing cost can be significantly reduced and the price of the wire grid polarizing element 1 can be reduced compared to a conventional polarizing element made of only an inorganic material.

On the other hand, in the conventional film type organic polarizing plate, since an organic material is often used, and the thicknesses of the substrate (base film), the double-sided tape (OCA: optically CLEAR ADHESIVE, optical adhesive), and the grid structure are increased, it is considered that the heat dissipation and the heat resistance are inferior to those of the hybrid type polarizing element 1 according to the present embodiment.

In the wire grid polarizing element 1 according to the present embodiment, the grid including the ridge portions 22 of the grid structure 20 and the reflective film 30 has a special tree shape (described in detail later) as shown in fig. 1 and the like. Thus, even when light is incident from an oblique direction at a wide range of incidence angles θ (for example, 30 to 60 °) with respect to the polarizing element 1, it is possible to suppress a decrease in the transmittance of the second polarized light (P polarized light) transmitted through the polarizing element 1 (that is, the transmission axis transmittance Tp) depending on the incidence angle θ of the obliquely incident light. Therefore, the product (tp×rs) of the reflectance (i.e., reflection axis reflectance Rs) of the first polarized light (S polarized light) reflected by the wire grid polarizing element 1 and the transmission axis transmittance Tp can be maintained at a high value of, for example, 70% or more. Therefore, as the polarizing element 1 according to the present embodiment, the polarization separation characteristic represented by tp×rs is excellent, and polarized light of obliquely incident light can be appropriately separated into S-polarized light (reflected light) and P-polarized light (transmitted light). Thus, the polarizing element 1 according to the present embodiment can obtain sufficient transmittance and polarization separation characteristics even for oblique incident light having a large incident angle θ and a wide range.

As described above, the wire grid polarizing element 1 according to the present embodiment is excellent in heat resistance and heat radiation, can be manufactured at a low cost, and is excellent in transmittance and polarization separation characteristics with respect to oblique incident light having a wide range of a large incident angle θ. Thus, the wire grid polarizing element 1 according to the present embodiment can be suitably used as various components for various products. For example, the polarizing element 1 may be applied to a polarizing beam splitter or the like provided in a smart display. The polarizing element 1 can be applied to a polarizing element provided in a head-up display (HUD) and adapted to handle heat from sunlight, a polarizing element adapted to handle heat from an LED light source, a polarized light reflector, and the like. The polarizing element 1 can also be applied to a polarizing beam splitter or the like provided in a headlight such as a variable light distribution headlight (ADB). The polarizing element 1 can be applied to a lens-integrated phase difference element, a lens-integrated polarizing element, and the like provided in various devices for Augmented Reality (AR) or Virtual Reality (VR).

< 2> Constituent elements of wire grid polarizing element

Next, the constituent elements of the wire grid polarizer 1 according to the present embodiment will be described in detail with reference to fig. 1,2, and the like.

<2.1. Substrate >

As shown in fig. 1, the wire grid polarizer 1 according to the present embodiment includes a transparent substrate 10. The substrate 10 is transparent and is made of an inorganic material having a certain degree of strength.

The material of the substrate 10 is preferably an inorganic material such as various glasses, quartz, crystal, or sapphire, more preferably an inorganic material having a thermal conductivity of 1.0W/m·k or more, and even more preferably an inorganic material having a thermal conductivity of 8.0W/m·k or more, from the viewpoint of obtaining more excellent heat dissipation and heat resistance.

The shape of the substrate 10 is not particularly limited, and may be appropriately selected according to the performance and the like required for the polarizing element 1. For example, the plate-like member may be formed to have a plate-like or curved surface. In addition, from the viewpoint of not affecting the polarization characteristics of the polarizing element 1, the surface of the substrate 10 may be a flat surface. The thickness TS of the substrate 10 is not particularly limited, and may be, for example, in the range of 0.02 to 10.0 mm.

<2.2. Grid Structure >

As shown in fig. 1 and 2, the polarizing element 1 according to the present embodiment includes the base portion 21 and the grid structure 20 having the grid-like ridge portions 22 on the substrate 10. The grid structure 20 is provided with a reflective film 30 described later on the ridge portions 22, and thus desired polarization characteristics can be obtained.

When light is incident on the polarizing element 1 from the surface side where the grid structure 20 is formed, a part of the incident light is reflected by the reflective film 30. The light having an electric field component in a direction orthogonal to the longitudinal direction of the ridge portion 22 (i.e., the extending direction of the ridge portion 22=the reflecting axis direction: the Y direction) (i.e., the width direction of the ridge portion 22=the transmitting axis direction: the X direction) among the light incident on the reflecting film 30 is transmitted through the polarizing element 1 with high transmittance. On the other hand, the light having the electric field component is increased in a direction parallel to the longitudinal direction of the ridge portion 22 (i.e., the extending direction of the ridge portion 22=the reflecting axis direction: Y direction) among the light incident on the reflecting film 30, and most of the light is reflected by the reflecting film 30. Therefore, in the present embodiment, by providing the grid structure 20 partially covered with the reflective film 30, it is possible to produce single polarized light. The same polarized light effect can be obtained also for light incident from the back surface side of the substrate 10.

As shown in fig. 1, the grid structure 20 includes a base portion 21. The base portion 21 is a film provided along the surface of the substrate 10, and is a portion for supporting the ridge portion 22. In the case where the uneven structure (raised line 22) of the grid structure 20 is formed by nanoimprinting or the like, the base portion 21 is necessarily formed. The base portion 21 and the ridge portion 22 are integrally formed of the same material. Further, since the grid structure 20 has the base portion 21, the strength of the ridge portion 22 can be enhanced as compared with the case where the ridge portion 22 is directly formed on the substrate 10. Therefore, the durability of the grid structure 20 can be improved. Further, since the base portion 21 is bonded to the substrate 10 over the entire surface, the peel resistance of the grid structure 20 can be improved.

The thickness TB of the base 21 is not particularly limited, but is preferably 1nm or more, more preferably 10nm or more, from the viewpoint of being able to more reliably support the ridge 22 and to facilitate press molding. Further, from the viewpoint of securing good heat dissipation, the thickness TB of the base portion 21 is preferably 50 μm or less, more preferably 30 μm or less.

Further, according to the polarizing element 1 of the present embodiment, the base portion 21 and the plurality of raised strips 22 of the grid structure 20 are directly formed on the substrate 10, so that the thickness TB of the base portion 21 can be reduced. Here, in order to improve the heat radiation performance from the grid structure 20 to the substrate 10, it is preferable to reduce the temperature difference Δt [ °c ] between the front surface and the back surface of the base portion 21 by reducing the thickness TB of the base portion 21. The temperature difference Δt is a temperature difference (Δt=t1-T2) between the temperature T1[ °c ] of the outermost surface of the base portion 21 (the root of the plurality of raised strips 22) and the temperature T2[ °c ] of the base portion 21 at the interface between the base portion 21 and the substrate 10.

Therefore, the thickness TB of the base portion 21 is preferably 0.15mm or less. Accordingly, the heat of the grid structure 20 made of the organic material can be quickly transferred to the substrate 10 made of the inorganic material, and the heat can be efficiently dissipated from the substrate 10 to the outside of the polarizing element 1, so that the temperature difference Δt can be set to, for example, 32 ℃. Further, the thickness TB of the base portion 21 is more preferably 0.09mm or less, whereby the temperature difference Δt can be set to, for example, 20 ℃ or less. Further, the thickness TB of the base portion 21 is more preferably 0.045mm or less, whereby the temperature difference Δt can be set to, for example, 10 ℃ or less. In addition, the thickness TB of the base 21 is particularly preferably 0.02mm or less, and thus the temperature difference Δt can be set to, for example, 5 ℃. In this way, by reducing the thickness TB of the base portion 21, the heat dissipation from the grid structure 20 to the outside via the substrate 10 can be improved, and therefore the heat dissipation and heat resistance of the polarizing element 1 can be improved.

As shown in fig. 1 and 2, the grid structure 20 includes a plurality of ridge portions 22 protruding from the base portion 21. The ridge portion 22 extends in the longitudinal direction with the reflection axis direction (Y direction) of the polarizing element 1 according to the present embodiment. The plurality of raised strips 22 are arranged at predetermined intervals in the X direction and spaced apart from each other by predetermined intervals, thereby forming a lattice-like uneven structure.

Here, as shown in fig. 1, in a longitudinal section (XZ section) of the polarizing element 1 orthogonal to the reflection axis (Y direction), the pitch P of the ridge portions 22 in the transmission axis (X direction) needs to be shorter than the wavelength of light in the use band. The reason for this is to obtain the above-described polarized light effect. More specifically, from the viewpoint of achieving both ease of manufacturing the ridge portions 22 and polarization characteristics, the pitch P of the ridge portions 22 is preferably 50 to 300nm, more preferably 100 to 200nm, and particularly preferably 100 to 150nm.

As shown in fig. 1 and 2, the width W _B of the bottom portion of the ridge portion 22 in the vertical section (XZ section) is not particularly limited, but is preferably 10 to 150nm, and more preferably 10 to 100nm, from the viewpoint of achieving both ease of manufacturing and polarization characteristics. The width W _T of the top of the ridge portion 22 is not particularly limited, but is preferably 5 to 60nm, more preferably 10 to 30nm, from the viewpoint of achieving both ease of manufacture and polarization properties.

The width W _B of the bottom portion and the width W _T of the top portion of the ridge portion 22 can be measured by observation with a scanning electron microscope or a transmission electron microscope. For example, a cross section (XZ cross section) orthogonal to the absorption axis direction or the reflection axis direction of the polarizing element 1 is observed by using a scanning electron microscope or a transmission electron microscope, and the width of the ridge 22 in the height position 20% above the height H of the ridge 22 from the bottom of the ridge 22 is measured for the ridge 22 at any 4 places, and these arithmetic averages may be set as the width W _B of the bottom of the ridge 22. Further, regarding the ridge 22 at any 4 points, the width of the ridge 22 at the height position 20% lower than the height H of the ridge 22 is measured from the tip 22a of the ridge 22, and the arithmetic average value may be set to the width W _T of the top of the ridge 22.

As shown in fig. 1, the height H of the ridge portion 22 in the longitudinal section (XZ section) is not particularly limited, but is preferably 50 to 350nm, more preferably 100 to 300nm, from the viewpoint of achieving both ease of manufacturing and polarization characteristics. The height H of the ridge 22 can be measured by scanning electron microscopy or transmission electron microscopy. For example, a cross section orthogonal to the absorption axis direction or the reflection axis direction of the polarizing element 1 is observed by using a scanning electron microscope or a transmission electron microscope, and the height of the ridge 22 at the center position in the width direction of the ridge 22 is measured for the ridge 22 at any 4 places, and the arithmetic average value of these can be set as the height H of the ridge 22.

In order to obtain good polarization separation characteristics for obliquely incident light, the shape of the ridge portions 22 of the grid structure 20 is preferably a head-thin shape. Here, the head-thin shape is a shape in which the width W of the ridge portion 22 (width in the X direction in the XZ cross section) gradually becomes narrower as it goes away from the base portion 21, in other words, the width W of the ridge portion 22 gradually becomes narrower as it goes from the bottom portion toward the top portion of the ridge portion 22. Therefore, when the ridge 22 has a head-thin shape, the width W _T of the top of the ridge 22 is smaller than the width W _B(W _T<W _B of the bottom of the ridge 22.

Fig. 3 shows a specific example of the head shape of the ridge portion 22 according to the present embodiment. As shown in fig. 3, if the cross-sectional shape of the ridge portion 22 in the longitudinal section (XZ section) is the head-thin shape, the width W may be a wide variety of shapes such as a trapezoid, a triangle, a bell shape, an ellipse, or a wedge shape with an arc, which becomes narrower as it goes away from the base portion 21. For example, the cross-sectional shape of the ridge 22A shown in fig. 3 is trapezoidal (tapered), the cross-sectional shape of the ridge 22B is triangular, the cross-sectional shape of the ridge 22C is bell-shaped, and the cross-sectional shape of the ridge 22D is wedge-shaped with circular arcs at the top and bottom. In this way, since the ridge portion 22 has a thin head shape, the reflection film 30 covering a part of the tip 22a and the side surface 22b of the ridge portion 22 is easily formed, and the polarization characteristic of the polarizing element 1 can be imparted, and the thin head shape can be formed by nanoimprint, which is also advantageous in terms of ease of manufacturing.

Further, the ridge portions 22 have a tapered shape such as a cone shape, so that the refractive index of the grid structure 20 gradually changes. Therefore, the same antireflection effect of the incident light by the change in the physical refractive index of the grid structure 20 can be obtained as in the moth-eye structure. This also has the effect of reducing the reflectance of the surface of the ridge portions 22 of the grid structure 20 and improving the permeability of the grid structure 20.

Fig. 4 shows a specific example of the shape of the concave portion 24 formed between the adjacent convex portions 22, 22. The concave portion 24 is a groove extending in the longitudinal direction (Y direction) of the ridge portion 22. As shown in fig. 4, if the cross-sectional shape of the recess 24 in the above-described longitudinal section (XZ section) is a shape in which the width becomes narrower toward the bottom of the recess 24, various shapes are possible. For example, the cross-sectional shape of the concave portion 24A shown in fig. 4 is a trapezoid (tapered shape), the cross-sectional shape of the concave portion 24B is a triangle (V-shape), the cross-sectional shape of the concave portion 24C is a substantially rectangular shape with a flat bottom, and the cross-sectional shape of the concave portion 24D is a U-shape with an arc at the bottom. The shape of the concave portions 24 may be appropriately selected in consideration of productivity such as releasability at the time of nanoimprint formation.

The material constituting the grid structure 20 is not particularly limited as long as it is a transparent organic material, and a known organic material can be used. For example, from the viewpoint of ensuring transparency and excellent manufacturing easiness, various thermosetting resins, various ultraviolet curable resins, and the like are preferably used as the material of the grid structure 20.

In addition, from the viewpoint of ease of production and production cost, the material constituting the grid structure 20 is preferably a material different from the substrate 10. When the materials of the grid structure 20 and the substrate 10 are different, the refractive indices of the two are different. Therefore, when the refractive index of the entire polarizing element 1 is affected, a refractive index adjusting layer may be provided between the grid structure 20 and the substrate 10 as appropriate.

For example, as a material constituting the grid structure 20, a curable resin such as an epoxy polymerizable compound or an acrylic polymerizable compound can be used. The epoxy polymerizable compound is a monomer, oligomer, or prepolymer having one or more epoxy groups in the molecule. Examples of the epoxy polymerizable compound include various bisphenol-type epoxy resins (bisphenol a type, F type, etc.), novolak (novolak) type epoxy resins, various modified epoxy resins such as rubber and polyurethane, naphthalene type epoxy resins, biphenyl type epoxy resins, phenol novolak type epoxy resins, stilbene type epoxy resins, triphenol methane type epoxy resins, dicyclopentadiene type epoxy resins, triphenylmethane type epoxy resins, prepolymers thereof, and the like.

The acrylic polymerizable compound is a monomer, oligomer, or prepolymer having one or more acrylic groups in the molecule. Here, the monomers are classified into a monofunctional monomer having one acrylic group in the molecule, a difunctional monomer having two acrylic groups in the molecule, and a multifunctional monomer having three or more acrylic groups in the molecule.

Examples of the "monofunctional monomer" include carboxylic acids (acrylic acid and the like), hydroxyl groups (2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate), alkyl or alicyclic monomers (isobutyl acrylate, t-butyl acrylate, isooctyl acrylate, lauryl acrylate, stearyl acrylate, isobornyl acrylate, and cyclohexyl acrylate), and other functional monomers (2-methoxyethyl acrylate, methoxyethylene glycol acrylate, 2-ethoxyethyl acrylate, tetrahydrofuranyl acrylate, benzyl acrylate, ethylcarbitol acrylate, phenoxyethyl acrylate, and N, N-dimethylaminoethyl acrylate, N-dimethylaminopropyl acrylate, N-dimethylacrylamide, acryloylmorpholine, N-isopropylacrylamide, N-diethylacrylamide, 2- (perfluorooctyl) ethyl acrylate, 3-perfluorohexyl-2-hydroxypropyl acrylate, 3-perfluorooctyl-2-hydroxypropyl-acrylate, 2- (perfluorodecyl) ethyl-acrylate, 2- (perfluoro-3-methylbutyl) ethyl acrylate), 2,4, 6-tribromophenol acrylate, 2,4, 6-tribromophenol methacrylate, 2- (2, 4, 6-tribromophenoxy) ethyl acrylate), 2-ethylhexyl acrylate, and the like.

Examples of the "bifunctional monomer" include tri (propylene glycol) diacrylate, trimethylolpropane-diallyl ether, and urethane diacrylate.

Examples of the "polyfunctional monomer" include trimethylolpropane triacrylate, dipentaerythritol penta-and hexa-acrylates, ditrimethylolpropane tetraacrylate, and the like.

Examples of the acrylic polymerizable compound other than the above-mentioned acrylic polymerizable compound include morpholine acrylate, glycerol acrylate, polyether acrylate, N-vinylformamide, N-vinylcaprolactam, ethoxydiglycol acrylate, methoxytriethylene glycol acrylate, polyethylene glycol acrylate, EO-modified trimethylolpropane triacrylate, EO-modified bisphenol A diacrylate, aliphatic urethane oligomer, polyester oligomer, and the like.

Examples of the curing initiator for the curable resin include a thermosetting initiator and a photo-curing initiator. The curing initiator may be any substance that cures by heat, light, or any energy ray other than light (e.g., electron beam). In the case where the curing initiator is a thermosetting initiator, the curable resin is a thermosetting resin, and in the case where the curing initiator is a photo-curing initiator, the curable resin is a photo-curable resin.

Among them, an ultraviolet curing initiator is preferably used as the curing initiator. The ultraviolet curing initiator is one of photo curing initiators. Examples of the ultraviolet curing initiator include 2, 2-dimethoxy-1, 2-diphenylethan-1-one, 1-hydroxy-cyclohexylphenyl ketone, and 2-hydroxy-2-methyl-1-phenylpropane-1-one. Therefore, the curable resin is preferably an ultraviolet curable resin. Further, from the viewpoint of transparency, the curable resin is more preferably an ultraviolet curable acrylic resin.

The method of forming the grid structure 20 is not particularly limited as long as the above-described base portion 21 and ridge portion 22 can be formed. For example, a concave-convex formation method realized by photolithography, imprinting, or the like may be used. Among them, from the viewpoint that the concave-convex pattern can be easily formed in a short time and the base portion 21 can be reliably formed, it is preferable that the base portion 21 and the convex strip portion 22 of the grid structure 20 are formed by embossing.

When the base portion 21 and the ridge portions 22 of the grid structure 20 are formed by nanoimprint, for example, after a material (grid structure material) for forming the grid structure 20 is applied to the substrate 10, a master having irregularities formed thereon is pressed against the grid structure material, and ultraviolet irradiation is performed in this state, and heat is applied thereto, so that the grid structure material can be cured. Thereby, the base portion 21 and the grid structure 20 having the convex portions 22 can be formed.

<2.3. Reflective film (functional film) >

As shown in fig. 1 and 2, the polarizing element 1 according to the present embodiment includes a reflective film 30 formed on the ridge portions 22 of the grid structure 20.

As shown in fig. 1, the reflective film 30 is formed so as to cover the front ends 22a and a part of the side surfaces 22b of the ridge portions 22 of the grid structure 20. As shown in fig. 1, the reflective film 30 is formed to extend in the longitudinal direction (Y direction) of the ridge portions 22 of the grid structure 20. Thus, the reflective film 30 can reflect light having an electric field component in a direction (reflection axis direction: Y direction) parallel to the longitudinal direction of the ridge portion 22 among the light incident on the polarizing element 1.

The material constituting the reflective film 30 is not particularly limited as long as it is a material having reflectivity for light of the use band. For example, a metal element monomer such as Al, ag, cu, mo, cr, ti, ni, W, fe, si, ge, te or a metal material such as an alloy containing 1 or more of these elements is exemplified.

The reflective film 30 may be a single-layer film made of the above metal, or may be a multilayer film made of a plurality of metal films. If the reflective film 30 has a reflective function, other layers such as a dielectric film may be included as necessary. The dielectric film is a thin film made of a dielectric substance. As a material of the dielectric film, a general material such as SiO ₂、Al ₂O ₃、MgF ₂、TiO ₂ can be used. The refractive index of the dielectric film is preferably greater than 1.0 and 2.5 or less. Further, since the optical characteristics of the reflective film 30 are also affected by the refractive index of the surroundings, the polarization characteristics can also be controlled by the material of the dielectric film.

<2.4. Special shapes of raised strips and reflective film >

Here, the specific shapes of the ridge portions 22 of the grid structure 20 and the reflective film 30 in the polarizing element 1 according to the present embodiment will be described in detail.

In the polarizing element 1 according to the present embodiment, as shown in fig. 1 and 5, the reflective film 30 is formed so as to cover the distal ends 22a of the ridge portions 22 and the upper side of at least one side surface 22b of the grid structure 20, and so as not to cover the lower sides of the both side surfaces 22b of the ridge portions 22 and the base portion 21. In the example of fig. 1 and 5, the reflective film 30 covers the upper side of the both side surfaces 22b of the ridge portion 22, but may cover only the upper side of the one side surface 22b of the ridge portion 22.

Here, the "state in which the reflective film 30 wraps the distal ends 22a of the ridge portions 22 and the upper side of at least one side surface 22b of the grid structure 20" means, for example, as shown in fig. 1 and 5, a state in which both the "distal ends 22a of the ridge portions 22" and the "upper side of the side surface 22b connecting the distal ends 22a of the ridge portions 22 and the base portion 21" are continuously wrapped by the reflective film 30, and the "lower side of the side surface 22 b" and the "base portion 21" are exposed without being wrapped by the reflective film 30. In this state, the reflective film 30 does not cover all of the side surfaces 22b of the ridge portions 22 (the front ends 22a of the ridge portions 22 to all of the side surfaces 22b of the base portion 21).

The surface of the reflective film 30 that wraps the distal ends 22a of the raised strips 22 and the upper side of at least one side surface 22b (hereinafter, sometimes referred to as "the top of the raised strips 22") has a curved shape (for example, a substantially elliptical shape in a longitudinal direction) with an arc, and bulges in the width direction (X direction) of the raised strips 22. In this way, the surface of the reflection film 30 has a smoothly curved surface shape, and does not have corner portions or stepped portions. The maximum width W _MAX of the reflective film 30 wrapping the tops of the ridges 22 in this manner is equal to or greater than the width W _B of the bottoms of the ridges 22. Also, W _MAX is preferably greater than W _B.

Here, the maximum width W _MAX of the reflection film 30 wrapping the ridge portion 22 is the largest horizontal width among the horizontal widths of the outermost surfaces of both sides of the reflection film 30 in the width direction (X direction) of the ridge portion 22. As shown in fig. 1, 5, etc., the horizontal width (width in the X direction) of the outermost surfaces of the reflective film 30 surrounding the ridge portion 22 varies depending on the height position (height in the Z direction) of the reflective film 30, but the maximum value among these horizontal widths is the maximum width W _MAX. In other words, the maximum width W _MAX is the maximum value of the sum of the thicknesses ds×2 of the both sides of the reflective film 30 and the horizontal width W of the ridge portion 22. For example, when light is incident on the grid structure 20 from the front direction (Z direction) (when the incident angle θ=0°), W _MAX corresponds to the effective grid width of the reflective film 30.

As shown in fig. 1 and 3, the width W _B of the bottom of the ridge portion 22 is the horizontal width (width in the X direction) of the ridge portion 22 at a height position (height in the Z direction) 20% of the height H of the ridge portion 22 from the lowermost portion (upper surface of the base portion 21) of the ridge portion 22. That is, the width W _B of the bottom of the ridge portion 22 is the horizontal width of the ridge portion 22 at a position 0.2×h upward from the upper surface of the base portion 21.

As shown in fig. 1 and 3, the width W _T of the top of the ridge 22 is equal to the horizontal width (width in the X direction) of the ridge 22 at a height position (height in the Z direction) 20% lower than the height H of the ridge 22 from the tip 22a of the ridge 22. That is, the width W _T of the top of the ridge portion 22 is the horizontal width of the ridge portion 22 at a position 0.8×h upward from the upper surface of the base portion 21 (i.e., at a position 0.2×h downward from the front end 22a of the ridge portion 22).

In the following description, the convex structure formed by the ridge portions 22 and the reflective film 30 is sometimes referred to as a "grid", and the height of the convex structure formed by the ridge portions 22 and the reflective film 30 (i.e., the grid) is sometimes referred to as a "grid height". The maximum width W _MAX of the reflection film 30 wrapping the ridge portion 22 is sometimes referred to as "grid maximum width W _MAX", and the width W _B of the bottom portion of the ridge portion 22 is sometimes referred to as "grid bottom width W _B". The width W _T of the top of the ridge 22 is sometimes referred to as "ridge top width W _T", and the width of the ridge 22 at the center in the height direction is sometimes referred to as "ridge center width".

As described above, in the present embodiment, as the width W _B of the bottom portion of the ridge portion 22, the horizontal width of the ridge portion 22 at the height position 20% above from the lowermost portion (bottom portion) of the ridge portion 22 is used, and as the width W _T of the top portion of the ridge portion 22, the horizontal width of the ridge portion 22 at the height position 20% below from the front end 22a of the ridge portion 22 is used. The reason for this is that it is difficult to precisely measure the widths of the lowermost portions of the raised strips 22 on the upper surface of the base 21 and the widths of the distal ends 22a of the raised strips 22 because of large variations in the manufacturing conditions of the grid structure 20.

As described above, in the grid structure 20 according to the present embodiment, the head-thin ridge portion 22 and the reflective film 30 that covers only the upper portion of the distal end 22a and the side surface 22b of the ridge portion 22 are formed. The lower side of the side surface 22b of the ridge portion 22 is not covered with the reflective film 30 and is opened.

As a result, the cross-sectional shape of the ridge portion 22 (i.e., the cross-sectional shape of the grid) surrounded by the curved reflective film 30 has a specific cross-sectional shape as follows. That is, as shown in fig. 1, 5, and the like, the horizontal width (for example, the grid maximum width W _MAX) of the portion on the upper side of the ridge portion 22 where the reflective film 30 exists is large, and the horizontal width (for example, the width W _B of the bottom portion of the exposed ridge portion 22) of the portion from the central portion to the bottom portion of the ridge portion 22 exposed without being covered with the reflective film 30 becomes small. The convex structure formed by the ridge portions 22 and the reflective film 30 has a cross-sectional shape of the whole (i.e., a "grid") and has a constricted portion, which is constricted on the inside and has a narrowed width in the X direction, at a position immediately below the lower end portion of the curved reflective film 30. The particular cross-sectional shape of such a grid may be exemplified by the shape of a tree. Specifically, the tree leaves with the large arc spread correspond to the portions of the reflective film 30 wrapping the tops of the ridges 22, the trunk of the tree corresponds to the lower side portions of the ridges 22 not covered with the reflective film 30, and the ground of the tree grows corresponds to the base 21. Therefore, in the following description, the particular cross-sectional shape of the grid constituted by the ridge portions 22 of the grid structure 20 and the reflective film 30 as described above is referred to as a "particular tree shape".

The grid of the grid structure 20 of the polarizing element 1 according to the present embodiment has the above-described special tree shape. As a result, for example, as shown in fig. 31 described later, when light enters the polarizing element 1 from an oblique direction, the effective grid width W _A is reduced and the gap width W _G is increased. Here, the effective grid width W _A is the width of the reflection film 30 in the direction perpendicular to the obliquely incident light. The gap width W _G is a width of a gap between the reflective films 30 and 30 of the two adjacent grids in a direction perpendicular to the obliquely incident light. The larger the effective grid width W _A, the more easily the obliquely incident light is reflected by the reflective film 30, and the more difficult it is to reach the transparent ridge portion 22 and the base portion 21. Therefore, the transmittance of obliquely incident light decreases in the polarizing element 1. On the other hand, as the gap width W _G is larger, the obliquely incident light is more likely to pass between the two adjacent reflection films 30 and reach the transparent ridge portion 22 and the base portion 21. This can improve the transmittance for oblique incident light.

Therefore, since the grid of the polarizing element 1 according to the present embodiment has the above-described special tree shape, the gap width W _G with respect to the obliquely incident light becomes large, and the obliquely incident light easily passes through the gaps of the circular reflective films 30 and 30, reaches the transparent grid structure 20, and is transmitted. Therefore, since the transmission axis transmittance Tp of oblique incident light is high, the transmittance and polarization separation characteristics (tp×rs characteristics) for oblique incident light are extremely excellent. Further, the reflection function of the oblique incident light by the reflection film 30 and the transmission function of the oblique incident light by the grid structure 20 can be realized in a balanced manner, and the polarization separation characteristic for the oblique incident light can be further improved.

<2.5. Method for Forming reflective film and specific example >

A method of forming the reflective film 30 will be described with reference to fig. 5.

As a method of forming the reflective film 30 so that the reflective film 30 covers the distal ends 22a and a part of the both side surfaces 22b of the ridge portions 22 of the grid structure 20, it is preferable that the ridge portions 22 of the grid structure 20 are inclined from the oblique direction (film formation incidence angle, as shown in fig. 5) Sputtering or vapor deposition is alternately performed to form the reflective film 30. Thus, the reflective film 30 can be formed so as to cover the upper sides of the distal ends 22a and both side surfaces 22b of the ridge portions 22. Further, a film formation incidence angle for forming the reflective film 30 by sputtering or vapor depositionThere is no particular limitation, but for example, it may be about 5 to 70 ° with respect to the surface of the substrate 10.

As described above, in the present embodiment, after the grid structure 20 made of the transparent material is formed, the reflective film 30 made of the metal material is formed by sputtering or vapor deposition. This makes it possible to easily change the film formation conditions, materials, and film thickness of the reflective film 30. In addition, even in the case where the reflection film 30 is constituted by a multilayer film, it can be easily handled. Therefore, by combining the metal, semiconductor, and dielectric, it is possible to design a film utilizing the interference effect, and it is not necessary to consider the etchable material configuration or the like when forming the etched reflective film 30 as in the conventional technique. This makes it easy to adjust the reflectance of the polarized light wave parallel to the grid structure 20 and the transmittance (transmission amount) of the polarized light in the direction perpendicular to the grid. Further, by forming the reflective film 30 after forming the grid structure 20, there is no need for equipment such as a vacuum Dry etching apparatus, and there is no need for complicated processes, and for preparing safety devices such as a gas and a pest control device for matching with the etching material. Thus, the running cost of equipment investment, maintenance, and the like can be reduced, and a cost advantage can be obtained.

The thickness Dt of the reflective film 30 covering the distal ends 22a of the raised strips 22 shown in fig. 5 and the thickness Ds of the reflective film 30 covering the side surfaces 22b of the raised strips 22 are not particularly limited, and may be appropriately changed depending on the shape of the raised strips 22 of the grid structure 20, the performance required of the reflective film 30, and the like. For example, from the viewpoint of obtaining more excellent reflection performance, the thicknesses Dt and Ds of the reflection film 30 are preferably set to 2 to 200nm, more preferably 5 to 150nm, still more preferably 10 to 100nm, and particularly preferably 15 to 80nm. As shown in fig. 5, the thickness Ds of the reflective film 30 is the thickness of the thickest part of the reflective film 30 covering the side surface 22b of the ridge portion 22.

The shape of the reflective film 30 is not particularly limited as long as it is a shape that can form the above-described special tree shape, and may be appropriately selected according to the conditions of the apparatus for forming the reflective film 30 and the performance required for the reflective film 30.

Fig. 6 is a cross-sectional view schematically showing a specific example of the shape of the reflection film 30. As shown in fig. 6, if the reflective film 30 is curved so as to cover the top (upper side of the distal end 22a and the side surface 22 b) of the ridge portion 22, it may have various shapes.

For example, the reflective film 30A shown in fig. 6 is coated so as to cover the tops of the convex portions 22A, 22B, and 22C having various cross-sectional shapes in an arc shape, and has a substantially elliptical shape that is greatly expanded in the width direction of the convex portion 22. The reflective film 30B has a curved shape so as to cover the top of the substantially wedge-shaped ridge portion 22D. The reflective film 30C has a curved shape so as to cover the top of the ridge portion 22A having a trapezoid shape. The coating ratio Rc of one side surface 22B of the ridge portion 22 coated with the reflective films 30B and 30C is substantially the same as the coating ratio Rc of the other side surface 22B.

The reflective film 30D covers the top of the substantially wedge-shaped ridge portion 22D, but is biased toward one side surface 22b (the left side surface 22b shown in fig. 6) of the ridge portion 22. Specifically, the reflective film 30D covers the left side surface 22b of the ridge portion 22 in a wide range, and the coating ratio Rc is about 80%. On the other hand, the reflective film 30D covers only the upper middle portion of the right side surface 22b in a narrow range, and the coating ratio Rc is 25%. As described above, the coating ratio Rc coated by the reflective film 30D may be different between the one side surface 22b and the other side surface 22b of the ridge portion 22.

<2.6. Preferable range of coating ratio Rc of raised strips coated with reflective film >

Next, preferred ranges of the coating rate Rc of the side surfaces 22b of the convex strips 22 coated with the reflective film 30 according to the present embodiment will be described.

The coating rate Rc is preferably 25% to 80%. Here, the coating ratio Rc is a ratio of the height (Hx) of the portion coated with the reflective film 30 in the side surface 22b of the ridge 22 to the height (H) of the ridge 22 shown in fig. 1 and 5. The coating ratio Rc is represented by the following formula (1).

Rc[％]＝(Hx/H)×100…(1)

H: height of the ridge 22 in Z direction

Hx: height in Z-direction of a portion of side surface 22b of ridge portion 22 covered with reflective film 30

The opening ratio Rr is a ratio of the height (H-Hx) of the portion of the side surface 22b of the ridge portion 22 that is not covered with the reflective film 30 to the height (H) of the ridge portion 22 shown in fig. 1 and 5. The opening ratio Rr is represented by the following formula (2).

Rr[％]＝((H-Hx)/H)×100…(2)

According to the definition above, rr=100-Rc. Thus, when the coating rate Rc of the side surface 22b of the ridge portion 22 coated with the reflective film 30 is 25% to 80%, the opening rate Rr of the side surface 22b of the ridge portion 22 coated with the reflective film 30 is 20% to 75%.

As described above, in the polarizing element 1 according to the present embodiment, the coating ratio Rc of the side surfaces 22b of the convex portions 22 coated with the reflective film 30 is preferably 25% to 80% (i.e., the opening ratio Rr is 20% to 75%). In detail, in the present embodiment, the reflective film 30 is formed so as to cover the distal ends 22a of the ridge portions 22 and the upper sides of the both side surfaces 22b, but not cover the lower sides of the both side surfaces 22b, and is opened. The coating rate Rc is preferably 25% to 80%, more preferably 30% to 70%, still more preferably 40% to 50%.

With the configuration, the polarizing element 1 according to the present embodiment can exhibit sufficient transmittance even for oblique incident light having a large incident angle θ (for example, 45 to 60 °). For example, when the obliquely incident light is split into S-polarized light (reflected light) and P-polarized light (transmitted light) by the polarizing element 1, the transmittance Tp of the P-polarized light (transmitted light) transmitted through the polarizing element 1 can be maintained at a high value regardless of the incident angle θ of the obliquely incident light. Further, by setting the coating ratio Rc to 25% or more and 80% or less, the contrast ratio (cr=tp/Ts) which is the ratio of the transmission axis transmittance (Tp) to the transmission axis reflectance (Ts) is maintained at a good level, and the reflection effect by the reflection film 30 can be more reliably exhibited irrespective of the incident angle θ. Therefore, high transmittance of the transmitted light can be ensured regardless of the incidence angle θ of the oblique incident light, to improve the polarization separation characteristic.

On the other hand, as a comparative example, it is considered that when the reflective film 30 is formed so as to cover only the front ends 22a of the ridge portions 22 of the grid structure 20 or is formed so as to cover the entire front ends 22a and the one-side surfaces 22b of the ridge portions 22 (for example, see fig. 18), the variation in the transmittance Tp becomes large depending on the incident angle θ of oblique incident light, and even oblique incident light having a large incident angle θ cannot obtain sufficient transmittance. In addition, as a comparative example, when the reflection film 30 entirely covers the front ends 22a and the both side surfaces 22b of the ridge portions 22 of the grid structure 20 (when the coating ratio Rc is 100%), the transmittance greatly decreases when the incidence angle θ of oblique incident light increases.

In this way, from the viewpoint of improving the transmittance and polarization separation characteristics of the transmitted light independently of the incident angle θ of the oblique incident light, it is preferable that the distal ends 22a of the ridge portions 22 and a part of at least one side surface 22b (upper side of the side surface 22 b) are covered with the reflective film 30 as in the polarizing element 1 according to the present embodiment.

In the polarizing element 1 according to the present embodiment, the coating ratio Rc of the side surface 22b of the ridge portion 22 coated with the reflective film 30 is preferably 25% to 80% from the viewpoint of tp×rs characteristics required as a Polarizing Beam Splitter (PBS) (for example, see fig. 27).

When the coating ratio Rc is less than 25%, the transmission axis transmittance Tp of the P-polarized light transmitted through the polarizing element 1 decreases, and depending on the incident angle θ, the transmittance Tp varies, and a sufficiently high value of tp×rs cannot be obtained. Therefore, sufficient transmittance of transmitted light and polarization separation characteristics represented by tp×rs cannot be obtained with respect to oblique incident light having a large incident angle θ. On the other hand, when the coating ratio Rc exceeds 80% (for example, see fig. 20), as in the case of covering the front ends 22a and the both side surfaces 22b of the ridge portions 22 of the grid structure 20 entirely, the larger the incidence angle θ of oblique incident light (for example, 45 to 60 °), the lower the transmission axis transmittance Tp, and therefore the larger the variation in the transmittance Tp depending on the incidence angle θ.

Therefore, the coating rate Rc of the side surface 22b of the ridge portion 22 coated with the reflective film 30 is preferably 25% to 80% (for example, see fig. 27). Accordingly, when light is incident from an oblique direction at an incident angle θ of, for example, 45 ° with respect to the polarizing element 1, the transmission axis transmittance Tp of the second polarized light (P polarized light) transmitted through the polarizing element 1 can be set to 75% or more. As a result, tp×rs can be set to 70% or more. Thus, even when oblique incident light having a wide range is incident at a large incident angle θ, the transmittance of the second polarized light (P polarized light) in the transmission axis direction of the polarizing element 1 can be improved, the polarization separation characteristic of the polarizing element 1 can be improved, and the oblique incident light can be appropriately separated into the first polarized light (S polarized light) and the second polarized light (P polarized light) by the polarizing element 1.

From the same viewpoint, the coating rate Rc is more preferably 30% to 70% (i.e., the opening rate Rr is 30% to 70%). Thus, under the oblique incidence condition, a high transmittance Tp of 80% or more can be obtained, and a high tp×rs of 72% or more can be obtained. The coating rate Rc is more preferably 30% to 60% (i.e., the opening rate Rr is 40% to 70%). Thus, under the oblique incidence condition, a high transmittance Tp of 83% or more can be obtained, and a high tp×rs of 75% or more can be obtained. Further, the coating rate Rc is more preferably 40% to 50% (i.e., the opening rate Rr is 50% to 60%). Thus, under the above oblique incidence condition, a very high transmittance Tp of 85% or more can be obtained, and a very high tp×rs of 77% or more can be obtained.

Further, regarding the reflection axis reflectance Rs, the coating ratio Rc is preferably 20% or more. Thus, under the above oblique incidence condition, a high reflectance Rs of 85% or more can be obtained.

Further, regarding the contrast CR of the transmitted light (cr=tp/Ts), if the coating ratio Rc is 20% or more, a sufficient contrast CR can be obtained. The higher the coating ratio Rc, the higher the contrast CR can be obtained.

<2.7. Preferred Range of Tp×Rs >

Next, a preferable range of "tp×rs" which is an index indicating the polarization separation characteristic of the wire grid polarizer 1 according to the present embodiment will be described.

Tp×Rs [% ] is expressed in percent as the product of the transmission axis transmittance (Tp) and the reflection axis reflectance (Rs). The tp×rs is an index indicating the polarization separation characteristic of the wire grid polarizer 1.

Tp×Rs[％]＝(Tp[％]/100)×(Rs[％]/100)×100

As described above, the transmission axis transmittance (Tp) is the transmittance of the second polarized light (P polarized light) having the electric field component parallel to the transmission axis (X direction) of the polarizing element 1. The reflection axis reflectance (Rs) is the reflectance of the first polarized light (S polarized light) having an electric field component parallel to the reflection axis (Y direction) of the polarizing element 1.

When the wire grid polarizing element 1 according to the present embodiment is used as a polarizing beam splitter to split incident light into S-polarized light and P-polarized light (see fig. 15 to 17), the polarizing element 1 is disposed so as to be inclined at a predetermined angle (for example, 45 °) with respect to the incident light from the light source. For example, when incident light from a light source is incident at an incident angle θ of the order of 45 ° with respect to the polarizing element 1, the incident light is separated into first polarized light (S polarized light: reflected light) and second polarized light (P polarized light: transmitted light) by the polarizing element 1. The S-polarized light is light having an electric field component in a direction parallel to the longitudinal direction (reflection axis direction: Y direction shown in fig. 2) of the ridge portions 22 of the grid structure 20 among the incident light. On the other hand, the P-polarized light is light having an electric field component in a direction parallel to the width direction (transmission axis direction: X direction shown in fig. 2) of the ridge portions 22 of the grid structure 20 among the incident light.

The S-polarized light in the reflection axis direction mainly becomes reflected light reflected by the reflection film 30 of the polarizing element 1. The reflectance [% ] of the S-polarized light at this time is the reflectance of the reflection axis (Rs). The reflectance (Rs) of the reflection axis indicates the proportion of S-polarized light reflected by the polarizing element 1 among S-polarized light incident on the polarizing element 1. The reflection axis transmittance (Rp) represents the proportion of S-polarized light transmitted through the polarizing element 1 among S-polarized light incident on the polarizing element 1.

On the other hand, the P-polarized light in the transmission axis direction is mainly transmitted light transmitted through the transparent grid structure 20 of the polarizing element 1 and the substrate 10. The transmittance [% ] of P-polarized light at this time is the transmittance on the transmission axis (Tp). The transmission axis transmittance (Tp) represents the proportion of P-polarized light transmitted through the polarizing element 1 among the P-polarized light incident on the polarizing element 1. The transmission axis reflectance (Ts) represents the proportion of P-polarized light reflected by the polarizing element 1 among the P-polarized light incident on the polarizing element 1.

Therefore, the higher transmission axis transmittance Tp means that P-polarized light in the transmission axis direction can be efficiently transmitted. The higher reflectance Rs of the reflection axis means that S-polarized light in the reflection axis can be efficiently reflected. Thus, the product of Tp and Rs, that is, the higher value of tp×rs is higher than both the transmittance of P-polarized light (transmitted light) and the reflectance of S-polarized light (reflected light), and the polarization separation characteristic as a polarization beam splitter is excellent.

Here, a preferred range of values of tp×rs according to the present embodiment will be described. Consider the case where light of a predetermined range of wavelengths (for example, 430 to 680 nm) is incident from an oblique direction at a predetermined incident angle θ (for example, 45 °) with respect to the polarizing element 1 according to the present embodiment, and is separated into P-polarized light (transmitted light) and S-polarized light (reflected light). In such oblique incidence conditions, tp×rs is preferably 70% or more from the viewpoint of good polarization separation characteristics of the polarizing element 1.

When tp×rs is less than 70%, in a display device to which a polarizing element is applied, the light utilization efficiency is poor, the brightness of a display image is insufficient, and the visibility is poor. On the other hand, if tp×rs is 70% or more, the light utilization efficiency in the display device to which the polarizing element 1 is applied is improved, and sufficient brightness of the display image can be ensured, and visibility can be improved.

Further, tp×rs is more preferably 72% or more, still more preferably 75% or more, and particularly preferably 80% or more. This can further improve the light utilization efficiency, brightness and visibility of the display image.

<2.8. Preferable range of height H of raised strips >

In the polarizing element 1 according to the present embodiment, when the incident light is incident at a relatively large incident angle θ (for example, 45 °), the height H (see fig. 1, 3, and the like) of the ridge portions 22 of the grid structure 20 is preferably 160nm or more, more preferably 180nm or more, and particularly preferably 220nm or more (see fig. 24). Thus, high transmittance Tp on the transmission axis, excellent tp×rs characteristics, and high contrast CR of transmitted light can be obtained.

Specifically, regarding the transmittance, if the height H of the ridge portion 22 is 160nm or more, the transmittance Tp of the oblique incident light on the transmission axis becomes 80% or more, and a high transmittance can be obtained. Further, if H is 180nm or more, tp of 85% or more can be obtained, which is more preferable. Further, if H is 220nm or more, 87% or more of Tp can be obtained, which is particularly preferable.

Further, regarding the characteristic of tp×rs required as a Polarizing Beam Splitter (PBS), if the height H of the ridge portion 22 is 160nm or more, excellent tp×rs of 70% or more can be obtained. Further, if H is 180nm or more, tp×Rs of 75% or more can be obtained, which is more preferable. Further, if H is 220nm or more, tp×Rs of 77% or more can be obtained, which is particularly preferable.

Further, regarding the contrast CR of the transmitted light (cr=tp/Ts), the height H of the ridge portion 22 may be 100nm or more, but if H is 160nm or more, an excellent contrast CR of 150 or more can be obtained. Further, if H is 180nm or more, excellent CR of 250 or more can be obtained, and is more preferable. Further, if H is 220nm or more, excellent CR of 500 or more can be obtained, so that it is particularly preferable.

As described above, it is known that in order to improve various characteristics (Tp, tp×rs, CR) of the polarizing element 1, particularly Tp, the height H of the ridge portion 22 is preferably larger. The reason for this is considered as follows. That is, the film formation incidence angle when the reflective film 30 is formed on the ridge portion 22 by sputtering, vapor deposition, or the likeWhen the height H of the ridge portion 22 is the same as shown in fig. 5, the coating ratio Rc coated by the reflective film 30 increases. When the coating ratio Rc increases, the range of the ridge portions 22 coated by the reflective film 30 increases, so that P-polarized light becomes difficult to pass through the grid structure 20, and the transmittance Tp decreases. Therefore, it can be said that the film formation incidence angleUnder the same conditions, it is preferable to further increase the height H of the ridge portion 22 to reduce the coating ratio Rc and increase the transmittance Tp.

<2.9. Preferred range of front end thickness Dt of functional film (reflective film) >)

In the polarizing element 1 according to the present embodiment, when the incident light is incident at a relatively large incident angle θ (for example, 45 °), the thickness Dt of the reflective film 30 covering the distal ends 22a of the ridges 22 of the grid structure 20 (the distal end thickness Dt of the reflective film 30: see fig. 5) is preferably 5nm or more, and more preferably 15nm or more (for example, see fig. 25).

If the front end thickness Dt of the reflective film 30 is 5nm or more, both the reflection axis reflectance Rs and the transmission axis transmittance Tp of oblique incident light become 85% or more, and high transmittance can be obtained. Further, in consideration of Tp characteristics and tp×rs characteristics required for the polarizing beam splitter, dt is more preferably 15nm or more.

<2.10. Preferred range of side thickness Ds of functional film (reflective film) >)

The thickness Ds of the reflective film 30 covering the side surfaces 22b of the ridge portions 22 of the grid structure 20 (side surface thickness Ds of the reflective film 30: see fig. 5) is preferably 10nm to 30nm, more preferably 12.5nm to 25nm, and particularly preferably 15nm to 25nm (see fig. 26, for example). Thus, high transmittance Tp on the transmission axis, excellent tp×rs characteristics, and high contrast CR of transmitted light can be obtained.

Specifically, regarding the transmittance, if the side surface thickness Ds of the reflective film 30 is 10nm or more and 30nm or less, the transmittance Tp of the obliquely incident light on the transmission axis becomes 80% or more, and a high transmittance can be obtained. Further, if Ds is 12.5nm or more and 25nm or less, tp of 85% or more is obtained, which is more preferable.

In addition, regarding the reflectance, if the side surface thickness Ds of the reflective film 30 is 10nm or more, the reflectance Rs of the oblique incident light becomes 80% or more, and a high reflectance can be obtained. Further, if Ds is 12.5nm or more, rs of 85% or more can be obtained, which is more preferable.

Further, regarding the characteristics of tp×rs required as a Polarizing Beam Splitter (PBS), if the side thickness Ds of the reflective film 30 is 12.5nm or more and 30nm or less, excellent tp×rs of 70% or more can be obtained. Further, if Ds is 15nm or more and 25nm or less, tp×Rs of 76% or more can be obtained, which is more preferable.

Further, regarding the contrast CR of the transmitted light (cr=tp/Ts), it is sufficient that the side surface thickness Ds of the reflective film 30 is 10nm or more, but if Ds is 12.5nm or more, an excellent contrast CR of 50 or more can be obtained. Further, if Ds is 15nm or more, CR of 100 or more can be obtained, which is more preferable.

<2.11 Deflection of reflective film >

The polarizing element 1 according to the present embodiment may have a shape that is asymmetric left and right in the width direction (X direction) of the ridge portion 22 so that the reflective film 30 covering the ridge portion 22 is biased to one side of the ridge portion 22 (see, for example, fig. 29). Specifically, the side surface thickness Ds, the coating ratio Rc, and the like of the reflection film 30 between the one side surface 22b and the other side surface 22b of the ridge portion 22 may be changed so that the reflection film 30 is biased toward the one side surface 22b of the ridge portion 22. That is, the reflective film 30 may cover the one side surface 22b of the ridge portion 22 thickly and widely, and cover the other side surface 22b thinly and narrowly.

When the reflective film 30 is biased to one side of the ridge portion 22 in this way, the difference between the transmission axis transmittance Tp (+) of the incident light having an incidence angle of +θ (+30° to +60°) with respect to the polarizing element 1 and the transmission axis transmittance Tp (-) of the incident light having an incidence angle of- θ (-30 ° to-60 °) is preferably 3% or less. In order to make the difference between Tp (+) and Tp (-) be within 3%, it is preferable to adjust the thickness Ds and the coating rate Rc of the reflective film 30 that coats the one side surface 22b and the other side surface 22b of the ridge portion 22, respectively, so that the reflective film 30 is appropriately biased to one side of the ridge portion 22.

The incidence angle +θ means that oblique light is incident on the ridge portion 22 from a direction oblique to the X direction (width direction of the ridge portion 22). On the other hand, an incidence angle of- θ means that oblique incident light is incident on the ridge portion 22 from a direction oblique to the other side of the X direction (see, for example, fig. 29).

As described above, when the reflective film 30 is biased to one side of the ridge portion 22, it is preferable that the difference between Tp (+) and Tp (-) is 3% or less. Thus, even when the reflective film 30 is biased to one side of the ridge portion 22, a high transmission axis transmittance Tp, excellent tp×rs characteristics, and a high contrast CR of transmitted light can be obtained.

Specifically, regarding the transmittance, even when the reflection film 30 is biased to one side, the transmittance Tp of the oblique incident light having the incident angle θ of +45° and-45 ° becomes 85% or more, and a high transmittance can be obtained.

In addition, regarding the reflectance, even when the reflection film 30 is biased to one side, the reflectance Rs of the oblique incident light having the incident angle θ of +45° and-45 ° becomes 85% or more, and a high reflectance can be obtained.

In addition, regarding the tp×rs characteristics required as a Polarizing Beam Splitter (PBS), even when the reflection film 30 is biased to one side, tp×rs of oblique incident light having an incident angle θ of 45 ° is 75% or more, and excellent tp×rs characteristics can be obtained.

Further, regarding the contrast CR of the transmitted light (cr=tp/Ts), even in the case of biasing the reflective film 30 to one side, excellent contrast CR can be obtained. Further, from the viewpoint of improving contrast, among the thicknesses Ds of the reflective films 30 covering the one side surface 22b and the other side surface 22b of the ridge portion 22, the thinner thickness Ds is preferably 5nm or more (the coating ratio Rc thereof is 22% or more), and the thickness Ds of the thinner reflective film 30 is more preferably 10nm or more (the coating ratio Rc thereof is 33% or more).

<2.12. Other constituent elements >

The polarizing element 1 according to the present embodiment may further include components other than the substrate 10, the grid structure 20, and the reflective film 30.

For example, as shown in fig. 7, the polarizing element 1 is preferably further provided with a protective film 40 formed so as to cover at least the surface of the reflective film 30. In detail, as shown in fig. 7, the protective film 40 more preferably covers the entire surface of the grid structure 20. That is, the protective film 40 is more preferably formed so as to entirely cover the side surfaces 22b of the ridge portions 22 of the grid structure 20, the surface of the base portion 21, and the surface of the reflective film 30. By forming the protective film 40, scratch resistance, stain resistance, and water repellency of the polarizing element 1 can be further improved.

The protective film 40 further preferably contains a water-repellent coating or an oil-repellent coating. This can further improve the stain resistance and the water repellency of the polarizing element 1.

The material constituting the protective film 40 is not particularly limited as long as it can improve the scratch resistance, the stain resistance, and the water resistance of the polarizing element 1. As a material constituting the protective film 40, for example, a film made of a dielectric material, more specifically, an inorganic oxide, a silane-based waterproof material, and the like can be cited. The inorganic oxide includes Si oxide, hf oxide, and the like. The silane-based waterproof material may contain a fluorinated silane compound such as perfluorodecyl triethoxysilane (FDTS) or a non-fluorinated silane compound such as Octadecyl Trichlorosilane (OTS).

Of these materials, at least one of an inorganic oxide and a fluorine-based waterproof material is more preferable. The scratch resistance of the polarizing element can be further improved by the protective film 40 containing an inorganic oxide, and the stain resistance and water resistance of the polarizing element can be further improved by the protective film containing a fluorine-based water-repellent material.

Further, although the protective film 40 may be formed so as to cover at least the surface of the reflective film 30, it is more preferable that it be formed so as to cover the entire surfaces of the grid structure 20 and the reflective film 30, as shown in fig. 7. In this case, for example, the protective film 40 may cover the end face of the grid structure 20 (the end face of the base portion 21) as shown in the upper diagram of fig. 7, or the protective film 40 may not cover the end face of the grid structure 20 (the end face of the base portion 21) as shown in the lower diagram of fig. 7. As shown in fig. 8, the protective film 40 may be formed so as to cover the entire polarizing element 1, including the surface of the substrate 10, in addition to the surfaces of the grid structure 20 and the reflective film 30. In this way, the heat resistance R of the entire polarizing element 1 can be further reduced by covering the outermost surface of the polarizing element 1 or the grid structure 20 with the protective film 40 made of an inorganic oxide, and therefore the heat dissipation performance of the polarizing element 1 can be further improved.

Further, the polarizing element 1 according to the present embodiment is preferably provided with a heat sink member 50 so as to surround the periphery of the substrate 10, as shown in fig. 9. The heat dissipation member 50 can release heat transferred from the substrate 10 more effectively. Here, the heat radiation member 50 is not particularly limited as long as it is a member having a high heat radiation effect. The heat sink 50 may be, for example, a heat sink (HEAT SPREADER), a die pad, a heat pipe, a metal cover, a housing, or the like.

<2.13. Image of actual grid Structure >

Next, an example of performing enlarged photographing using a Scanning Electron Microscope (SEM) will be described with reference to fig. 10, in which the polarizing element 1 according to the present embodiment is actually manufactured. Fig. 10A is an SEM image of the grid structure 20 before being covered with the reflective film 30, as viewed from an oblique direction. Fig. 10B is an SEM image showing a cross section of the ridge portions 22 of the grid structure 20 before being covered with the reflective film 30. Fig. 10C is an SEM image showing a cross section of the ridge portion 22 of the grid structure 20 covered with the reflective film 30.

As shown in fig. 10A and 10B, the grid structure 20 includes a base portion 21 provided along the surface of the substrate 10 and a ridge portion 22 protruding from the base portion 21. The plurality of raised strips 22 are arranged at an almost equal pitch P. Each ridge 22 has a head-thin shape whose width becomes narrower as it is away from the base 21. The width W _T of the top of the ridge 22 is narrower than the width W _B of the bottom of the ridge 22. The pitch P is sufficiently greater than the width W _B of the bottom of the ridge 22. The height H of the ridge 22 is greater than the pitch P. In the example of fig. 10, p=140 nm, W _T＝10nm、W _B =30 nm, h=220 nm. As shown in fig. 10C, the reflective film 30 is formed so as to cover the front ends 22a and both side surfaces 22b of the ridge portions 22. The outer surface of the reflective film 30 is curved with an arc, and bulges in the width direction of the ridge portion 22.

<3 > Method for producing polarizing element

Next, a method of manufacturing the wire grid polarizing element 1 according to the present embodiment will be described with reference to fig. 11. Fig. 11 is a process diagram showing a method for manufacturing the wire grid polarizer 1 according to the present embodiment.

As described above, the polarizing element 1 according to the present embodiment is a hybrid wire grid polarizing element 1 composed of an inorganic material (substrate 10) and an organic material (grid structure 20). A method of manufacturing the hybrid wire grid polarizer 1 will be described below.

As shown in fig. 11, the method for manufacturing the wire grid polarizing element 1 according to the present embodiment includes: a grid structure material forming step (S10), a nanoimprint step (S12), a grid structure forming step (S14), and a reflective film forming step (S16).

Grid Structure Material Forming step (S10)

First, in S10, a grid structure material 23 made of a transparent organic material (for example, an ultraviolet curable resin or a thermosetting resin) is laminated on a substrate 10 made of a transparent inorganic material (for example, glass) by coating or the like. As the inorganic material of the substrate 10, the above-described various materials can be used. As the organic material of the grid structure 20, the above-described various materials can be used. The film thickness of the grid structure material 23 may be appropriately adjusted according to the dimensions of the base portion 21 and the ridge portion 22 of the grid structure 20 formed by the nanoimprint of S20.

Nanoimprint step (S12) and grid Structure Forming step (S14)

Next, in S12, nanoimprinting is performed on the grid structure material 23, and in S14, the grid structure 20 is formed on the substrate 10. The grid structure 20 is a fine uneven structure in which a base portion 21 provided on the substrate 10 and a plurality of ridge portions 22 protruding from the base portion 21 are integrally formed. The fine concave-convex structure is, for example, a structure having fine convex portions and concave portions on the order of several nm to several tens of nm.

In the nanoimprint step of S12, the master 60 having the inverse of the fine concave-convex shape of the grid structure 20 is used, and the fine concave-convex shape of the master 60 is transferred onto the surface of the grid structure material 23 (S12). Thus, the concave-convex pattern composed of the base portion 21, the convex portions 22, and the concave portions 24 is formed in the grid structure material 23. In the nanoimprint step, the concave-convex pattern is transferred, and the grid structure material 23 is irradiated with energy rays, so that the grid structure material 23 to which the concave-convex pattern is transferred is cured, thereby forming the grid structure 20 (S14). For example, in the case where the grid structure material 23 is made of an ultraviolet curable resin, the ultraviolet curable resin to which the uneven pattern is transferred may be cured by irradiating ultraviolet rays to the grid structure material 23 using the ultraviolet irradiation device 66. Alternatively, in the case where the grid structure material 23 is made of a thermosetting resin, the heating device 68 such as a heater may be used to heat the grid structure material 23, thereby curing the thermosetting resin to which the uneven pattern is transferred.

In the steps S12 and S14, the ridge portions 22 having the tapered shape, which becomes narrower as the width thereof becomes farther from the base portion 21, are formed as the ridge portions 22 of the grid structure 20. The ridge 22 in the example of fig. 11 is trapezoidal (tapered), but may be of other various head shapes as shown in fig. 3.

As described above, in the present embodiment, since the raised strips 22 having the head-thin shape are embossed in the nanoimprint step S12, the master 60 can be easily peeled from the grid structure material 23, and the mold stripping performance is excellent. Further, the ridge portions 22 of the grid structure 20 can be precisely molded into a desired shape without deformation.

Reflective film forming step (S16)

Next, in S16, the reflective film 30 covering a part of the ridge portions 22 of the grid structure 20 is formed using a metal material such as Al or Ag. The reflective film 30 is an example of a functional film that imparts a predetermined function to the polarizing element 1. The reflection film 30 is a thin metal film (a grid of thin metal wires) for reflecting the incident light to the grid structure 20 of the polarizing element 1.

In this reflective film forming step S16, the reflective film 30 is formed as follows. That is, the reflective film 30 is formed so as to cover the distal ends 22a of the ridge portions 22 and the upper side of at least one side surface 22b, and not cover the lower sides of the both side surfaces 22b of the ridge portions 22 and the base portion 21. The surface of the reflective film 30 surrounding the ridge portion 22 is formed to have an arc and to be bulged in the width direction of the ridge portion 22, so that the reflective film 30 is formed. The reflective film 30 is formed so that the maximum width W _MAX (the grid maximum width W _MAX) of the reflective film 30 surrounding the ridge portion 22 is equal to or greater than the width W _B (the grid bottom width W _B) of the bottom portion of the ridge portion.

As a method for forming such a reflective film 30, for example, as shown in fig. 5, sputtering or vapor deposition may be used. The reflective film 30 is formed by alternately sputtering or vapor-depositing a metal material from an oblique direction with respect to the ridge portions 22 of the grid structure 20. Thus, the reflective film 30 having a desired shape can be appropriately formed so as to cover the top of the ridge portion 22 in an arc shape.

By forming the reflective film 30 in this manner, the ridge portions 22 of the grid structure 20 and the reflective film 30 have the above-described special tree shape. As described above, even when light is incident on the polarizing element 1 from an oblique direction at a relatively large and wide incidence angle θ (for example, 30 to 60 °), the transmission axis transmittance Tp of P-polarized light contained in the obliquely incident light can be maintained at a high value, and the transmittance of P-polarized light (transmitted light) can be ensured. This can maintain the value of tp×rs at a high value (for example, 70% or more), and thus can improve the polarization separation characteristic of the polarization element 1 with respect to oblique incident light.

The method for manufacturing the polarizing element 1 according to the present embodiment may include: after the reflective film forming step S16 shown in fig. 11, a protective film 40 is formed to cover the surface of the polarizing element 1 as necessary (protective film forming step). The protective film 40 is preferably formed so as to cover the entire surfaces of the grid structure 20 and the reflective film 30. As a material of the protective film 40, the above-described various materials can be used.

The method for manufacturing the polarizing element 1 according to the present embodiment is described above. Through the above-described steps, the polarizing element 1 having excellent polarization characteristics and heat dissipation properties can be manufactured without increasing the manufacturing cost and complicating the manufacturing process of the polarizing element 1.

Here, for comparison with the manufacturing method according to the present embodiment, a conventional method for manufacturing a wire grid polarizer will be briefly described with reference to fig. 12.

As shown in fig. 12, in the conventional method for manufacturing a wire grid polarizer, first, a metal film 80 is formed on a substrate 10 in order to form a convex grid shape (S20). In S20, a reflective film made of a material or the like that reflects light in a use wavelength band, for example, a metal film 80 made of aluminum or the like is formed on the substrate 10 made of an inorganic material such as glass by sputtering or vapor deposition.

Next, the resist mask 70 is drawn on the metal film 80 using a photolithography technique (S22). Then, the metal film 80 is etched by a vacuum dry etching apparatus or the like, thereby forming a convex shape composed of the metal film 80 (S24). For example, in this case, when the etching selectivity of the resist mask 70 and the metal film 80 is not obtained, an oxide film such as SiO ₂ is further formed on the metal film 80 by sputtering or the like, and the resist mask 70 is formed thereon by a photolithography technique. After the resist mask 70 is peeled off from the metal film 80 (S26), the protective film 40 made of SiO ₂ film or the like is formed by CVD or the like, and if necessary, a water/oil repellent coating layer treatment is further performed (S28).

Although the steps S20 to S28 of the conventional manufacturing method described above show the process of manufacturing the reflective wire grid polarizer having the basic structure, a complicated process is required when considering the case where the metal film 80 is a multilayer film. Therefore, it can be estimated that the conventional wire grid polarizer manufactured by the process shown in S20 to S28 of fig. 12 is expensive to manufacture and requires a long time to manufacture. In addition, in the case of mass production of polarizing elements, it is expected that in order to form a fine convex shape smaller than the wavelength of light, it is necessary to prepare a plurality of high-precision etching apparatuses and photolithography apparatuses by blending the output, and the equipment investment is also increased.

In contrast, in the method for manufacturing the polarizing element 1 according to the present embodiment (see fig. 11), since the grid structure 20 is molded by using an imprint technique such as nanoimprint, manufacturing costs, manufacturing time, and equipment investment can be significantly reduced as compared with the conventional manufacturing method (see fig. 12).

In the method for manufacturing the polarizing element 1 according to the present embodiment, nanoimprinting is performed on the grid structure material 23 (S12 in fig. 11), but the conditions of nanoimprinting are not particularly limited. For example, as shown in S12 of fig. 11, a replica master (master may be) is used as the master 60, nanoimprinting is performed, UV irradiation, heating, or the like is performed on the grid structure material 23, and the grid structure material 23 is cured in a state where the concave-convex pattern is imprinted. Then, the master 60 is released from the cured grid structure material 23. In this way, the grid structure 20 formed with the base portion 21 and the ridge portion 22 can be molded by transfer printing.

The master 60 used in the nanoimprint step S12 (fig. 11) in the method for manufacturing the polarizing element 1 according to the present embodiment can be manufactured by, for example, a photolithography technique as shown in fig. 13. Fig. 13 is a process diagram showing a method for manufacturing the master 60 according to the present embodiment.

As shown in fig. 13, first, after a master metal film 62 is formed on a master substrate 61 (S30), a resist mask 70 is formed on the master metal film 62 (S32). Next, the metal film 62 for a master is etched using the resist mask 70, and grooves 65 corresponding to the ridges 22 of the grid structure 20 are formed in the etched metal film 62 for a master (S34).

Then, the resist mask 70 is peeled off from the metal film 62 for a master, and the master 60 is obtained (S36). The master 60 has a fine uneven structure composed of a plurality of projections 63 and grooves 65 formed on a master substrate 61. The fine uneven structure of the surface of the master 60 has an inverted shape of the fine uneven structure of the surface of the grid structure 20 of the polarizing element 1. The grooves 65 of the master 60 have a reverse shape of the ridges 22 of the grid structure 20, and the protrusions 63 of the master 60 have a reverse shape of the recesses 24 between the ridges 22, 22 of the grid structure 20.

The manufacturing method according to the present embodiment may further include a step of forming a release film coating layer 64 on the surface of the fine uneven structure of the master 60, if necessary (S38). By providing the release film coating layer 64 on the surface of the master 60, after nanoimprinting is performed on the grid structure material 23 in the nanoimprinting step (S12) shown in fig. 11, the master 60 can be easily peeled off from the grid structure material 23, and the releasability can be further improved.

<4 > Projection display device

Next, a projection display device to which the wire grid polarizing element 1 according to the present embodiment is applied will be described with reference to fig. 14.

The projection display device according to the present embodiment includes the wire grid polarizing element 1 according to the present embodiment described above. The projection display device according to the present embodiment is provided with the polarizing element 1, whereby excellent polarization characteristics, heat resistance, heat dissipation, and the like of the polarizing element 1 can be achieved.

Here, the projection display device is a device that projects light toward an object and irradiates the projected light (projection light) onto a display surface (projection surface) of the object to display a virtual image such as an image or a video. Examples of the type of projection display device include head-up display devices (HUDs) and projector devices.

<4.1. Head-up display device >

First, a head-up display device 100 including the wire grid polarizing element 1 according to the present embodiment will be described with reference to fig. 14. Fig. 14 is a schematic diagram showing an example of the head-up display device 100 according to the present embodiment.

As shown in fig. 14, the head-up display device 100 according to the present embodiment includes the wire grid polarizing element 1 according to the present embodiment described above. The head-up display device 100 includes the polarizing element 1, thereby improving polarization characteristics, heat resistance, and heat dissipation. Since a head-up display incorporating a conventional polarizing element has poor heat dissipation, it is considered that heat resistance is insufficient when dealing with long-term use and subsequent high brightness and enlarged display.

As shown in fig. 14, the head-up display device 100 includes a light source 2, a display element 3 for emitting a display image, a reflector 4 for reflecting the display image on a display surface 5, and a cover 6 provided at an opening of a cover 7. In the head-up display device 100, the configuration of the polarizing element 1 is not particularly limited. For example, as shown in fig. 14, the polarizing element 1 may be arranged between the display element 3 and the reflector 4.

Here, the head-up display device 100 may be a head-up display device mounted on a vehicle. The in-vehicle head-up display device displays an image on a semi-transparent panel (corresponding to the "display surface 5") such as a windshield or a combination panel of a vehicle. The in-vehicle head-up display device is an image display device that is disposed in an instrument panel of a vehicle, projects image light onto a windshield (display surface 5), and displays driving information as a virtual image, for example.

The head-up display device 100 is configured to emit a display image from below toward a windshield surface (display surface 5). Therefore, sunlight may enter the display element 3 in the opposite direction of the emission direction of the display image. The head-up display device 100 according to the present embodiment is provided with a reflector 4 for reflecting and enlarging a display image for the purpose of downsizing and enlarging the display image. In this case, in the conventional head-up display device, sunlight entering the reflector from the outside is concentrated in the vicinity of the display element, and there is a possibility that the display element may be degraded or malfunction due to heat.

In contrast, in the head-up display device 100 according to the present embodiment, the hybrid-type polarizing element 1 having excellent heat dissipation and heat resistance is provided as described above for the purpose of preventing sunlight from entering the display element 3. The polarizing element 1 can stably exhibit a polarized light function even at a high temperature of about 200 ℃. Therefore, for example, even in a high-temperature environment such as in a car in summer, sunlight entering the reflector 4 from the outside can be blocked by the polarizing element 1 to prevent the sunlight from reaching the display element 3, so that deterioration and failure of the display element 3 can be suppressed.

The example of the constituent elements of the head-up display device 100 shown in fig. 14 is not limited to the example of fig. 14, and other constituent elements may be appropriately provided according to the required performance or the like.

Further, by using the polarizing element 1 as a pre-polarizing plate disposed before the display element 3, the polarizing element 1 can transmit a display image emitted from the display element 3 and suppress incidence of the sunlight to the display element 3. Therefore, the heat resistance and durability of the head-up display device 100 can be further improved.

The arrangement of the wire grid polarizer in the projection display device is not limited to the example of the arrangement of the polarizer 1 in the head-up display device 100 shown in fig. 14, and may be appropriately selected and changed according to the configuration of the projection display device, required performance, and the like. For example, although not shown, the polarizing element 1 may be arranged between the display element 3 and the light source 2. In addition, although not shown, the polarizing element 1 may be assembled into the reflector 4. The cover 6 provided in the head-up display device 100 shown in fig. 14 may be constituted by the polarizing element 1.

Although not shown, a heat sink member 50 may be provided around the polarizing element 1 provided in the head-up display device 100 (see fig. 9). The heat dissipation property of the polarizing element 1 can be further improved by the heat dissipation member 50, and therefore the polarization characteristics and heat resistance of the polarizing element 1 can be further improved.

<4.2. Projection display apparatus having polarizing beam splitter >

Next, a projection display device using the reflective wire grid polarizing element 1 according to the present embodiment as the polarizing beam splitter 230 will be described with reference to fig. 15 to 17. First, a general description will be given of matters common to 3 specific examples of the projection display devices 200A, 200B, and 200C (hereinafter, may be collectively referred to as "projection display device 200") shown in fig. 15 to 17. Next, specific examples shown in fig. 15 to 17 will be described one by one.

As shown in fig. 15 to 17, the projection display device 200 includes a light source 210, a PS converter 220, a polarization beam splitter 230, a reflective liquid crystal display element 240, and a lens 250. A phase difference compensation plate (not shown) may be provided between the polarizing beam splitter 230 and the reflective liquid crystal display element 240.

The light source 210 may be a point light source having 1 light emitting portion, or may be a light source having a plurality of light emitting portions such as LEDs. The light emitted from the light source 210 may be parallel light or diffuse light. Therefore, the light of the light source 210 is incident on the polarization beam splitter 230 (reflective linear grating polarization plate) at an incidence angle θ in a predetermined range (for example, a range of 45 ° ± 15 °) centered at 45 ° forexample.

The PS converter 220 is a polarized light conversion element for converting light from the light source 210 into specific polarized light (for example, P-polarized light or S-polarized light). PS converter 220 may convert light from light source 210 into P-polarized light, or into S-polarized light.

Polarizing beam splitter 230 is comprised of a reflective linear grating polarizing plate. The reflective wire grid polarizing plate is an example of the wire grid polarizing element 1 according to the present embodiment. The polarization beam splitter 230 is configured to make light from the light source 210 incident at an incidence angle θ of a prescribed range including 45 °. The incidence angle θ in the predetermined range is, for example, 45 ° ± 15 °, i.e., 30 ° or more and 60 ° or less.

For example, in fig. 15 to 17, the polarization beam splitter 230 is disposed at an angle of 45 ° with respect to the incident direction of the incident light, so that the incident light from the light source 210 is mainly incident at an incident angle θ of 45 ° with respect to the polarization beam splitter 230. Further, the polarization beam splitter 230 is disposed at an inclination of 45 ° with respect to the reflective liquid crystal display element 240, so that the incident light from the reflective liquid crystal display element 240 is mainly incident at an incident angle θ of 45 ° with respect to the polarization beam splitter 230.

The polarizing beam splitter 230 splits incident light into first polarized light (S polarized light) and second polarized light (P polarized light). For example, the polarization beam splitter 230 may reflect a first polarized light (S polarized light) among the incident lights and transmit a second polarized light (P polarized light) to separate the S polarized light and the P polarized light. In contrast, the polarization beam splitter 230 may reflect the second polarized light (P polarized light) among the incident light and transmit the first polarized light (S polarized light), thereby separating the S polarized light and the P polarized light.

When the desired polarized light is reflected by the polarization beam splitter 230, the polarization beam splitter 230 is disposed so that light including the polarized light to be reflected is incident on the surface of the polarization beam splitter 230 (i.e., the concave-convex surface on the side where the grid structure 20 of the polarizing element 1 is formed). For example, as shown in fig. 15, when S-polarized light incident from PS converter 220 is reflected by polarization beam splitter 230, the surface of polarization beam splitter 230 may be directed toward PS converter 220 side from which S-polarized light is emitted. On the other hand, as shown in fig. 16, when S-polarized light incident from the reflective liquid crystal display element 240 is reflected by the polarization beam splitter 230, the surface of the polarization beam splitter 230 may be directed toward the reflective liquid crystal display element 240 from which the S-polarized light is emitted.

The reflective liquid crystal display element 240 is a display element that reflects incident light and emits light representing a display image. As shown in fig. 15 and 17, the reflective liquid crystal display element 240 may be configured such that the first polarized light (S polarized light) reflected by the polarization beam splitter 230 is incident on the surface of the reflective liquid crystal display element 240. Alternatively, as shown in fig. 16, the reflective liquid crystal display element 240 may be arranged such that the second polarized light (P polarized light) transmitted through the polarization beam splitter 230 is incident on the surface of the reflective liquid crystal display element 240.

As shown in fig. 15 and 17, the reflective liquid crystal display element 240 reflects and modulates the incident first polarized light (S polarized light) and emits the second polarized light (P polarized light) representing the display image. However, not limited to the example, as shown in fig. 16, the reflective liquid crystal display element 240 may reflect and modulate the incident second polarized light (P polarized light) and emit the first polarized light (S polarized light) representing the display image.

The lens 250 amplifies the light representing the display image emitted from the reflective liquid crystal display element 240 and outputs the amplified light to the outside. The lens 250 is disposed so that light representing a display image emitted from the reflective liquid crystal display element 240 enters through the polarization beam splitter 230. For example, as shown in fig. 15 and 17, the lens 250 may be arranged so that the second polarized light (P polarized light) reflected and modulated by the reflective liquid crystal display element 240 is transmitted through the polarization beam splitter 230 and is incident on the lens 250. Alternatively, as shown in fig. 16, the lens 250 may be arranged such that the first polarized light (S polarized light) reflected and modulated by the reflective liquid crystal display element 240 is reflected by the polarization beam splitter 230 and enters the lens 250.

As described above, in the projection display device 200 according to the present embodiment, the wire grid polarizing element 1 according to the present embodiment described above is used as the polarizing beam splitter 230. Accordingly, the polarization beam splitter 230 is excellent in reflectivity of S-polarized light, permeability of P-polarized light, tp×rs characteristics, and characteristics of separating oblique incident light into P-polarized light and S-polarized light for oblique incident light having a relatively large and wide incident angle θ (for example, 30 to 60 °).

Next, specific examples of the projection display devices 200A, 200B, and 200C shown in fig. 15 to 17 will be described one by one.

As shown in fig. 15, the projection display device 200A according to the first specific example of the present embodiment includes a light source 210, a PS converter 220, a polarization beam splitter 230, a reflective liquid crystal display element 240, and a lens 250.

The light emitted from the light source 210 is unpolarized light, and the light includes a P-polarized light component and an S-polarized light component in equal proportion. Therefore, when only one of the polarized lights is selected and extracted by the polarization beam splitter 230 composed of the polarizing element 1, the light quantity is reduced by about half. Here, the light emitted from the light source 210 is converted into one of first polarized light (S polarized light) or second polarized light (P polarized light) by the PS converter 220. This suppresses a decrease in the amount of polarized light extracted by the polarization beam splitter 230, thereby improving the light utilization efficiency. For example, PS converter 220 shown in fig. 15 converts light from light source 210 into first polarized light (S polarized light).

The light converted into S-polarized light by the PS converter 220 is incident on the polarization beam splitter 230 disposed obliquely to the extent of 45 °. The polarization beam splitter 230 reflects the first polarized light (S polarized light) and emits it toward the reflective liquid crystal display element 240 at an emission angle of 45 °. The reflective liquid crystal display element 240 modulates and reflects the first polarized light (S polarized light), generates second polarized light (P polarized light) representing a display image, and emits the second polarized light (P polarized light) toward the polarization beam splitter 230. The second polarized light (P polarized light) passes through the polarization beam splitter 230 and is amplified by the lens 250, and then is projected onto a display surface (not shown) to display a display image.

The projection display device 200A having the above-described configuration includes, as the polarization beam splitter 230, a reflective wire grid polarizing plate including the wire grid polarizing element 1 according to the present embodiment. Accordingly, the polarization separation characteristic of the polarization beam splitter 230 can be improved, and the heat radiation performance and heat resistance of the polarization beam splitter 230 and the projection display device 200A can be improved with respect to the incident light from the oblique direction and the incident light having a wide incident angle θ.

In contrast, in a projection display device (not shown) including a conventional polarizing element as a polarizing beam splitter, the heat dissipation of the polarizing element is poor. Therefore, from the viewpoints of coping with long-term use, high brightness, and enlarged display, heat resistance is considered to be insufficient. The incident angle θ of light entering the polarization beam splitter is not only 45 °, but also all angles within a predetermined range (for example, about 45 ° ± 15 °) centered around 45 °. In this way, even when oblique incident light having a large and wide incident angle θ is incident on the polarization beam splitter, the polarization beam splitter has been required to have a performance of appropriately separating the oblique incident light into S-polarized light and P-polarized light regardless of the incident angle θ. However, in the polarizing beam splitter using the conventional polarizing element, since the polarization separation characteristic with respect to the obliquely incident light is poor, the light utilization efficiency is deteriorated, and the adverse effect on the image quality of the display image such as the luminance unevenness becomes a problem.

In this regard, the polarization beam splitter 230 of the projection display device 200A according to the first specific example of the present embodiment is excellent in polarization separation characteristics for oblique incident light having the incident angle θ as described above which is large and wide. Accordingly, the projection display device 200A can improve the efficiency of light use and reduce uneven brightness, thereby improving the image quality of the display image.

The projection display device is not limited to the example of the projection display device 200A shown in fig. 15, and for example, the constituent elements and the arrangement of the projection display device may be appropriately changed as in the projection display device 200B shown in fig. 16 or the projection display device 200C shown in fig. 17.

As shown in fig. 16, a projection display device 200B according to a second specific example of the present embodiment includes a light source 210, a PS converter 220, a polarization beam splitter 230, a reflective liquid crystal display element 240, and a lens 250.

In the projection display device 200B, the PS converter 220 converts the light from the light source 210 into second polarized light (P polarized light). The light converted into P-polarized light by the PS converter 220 is transmitted through the polarization beam splitter 230 disposed obliquely at an angle of 45 ° and enters the reflective liquid crystal display element 240. The reflective liquid crystal display element 240 modulates and reflects the second polarized light (P polarized light), generates the first polarized light (S polarized light) representing the display image, and emits the first polarized light (S polarized light) toward the polarization beam splitter 230. The polarization beam splitter 230 reflects the first polarized light (S polarized light) and emits the first polarized light toward the lens 25 at an emission angle of 45 °. The first polarized light (S polarized light) is magnified by the lens 250 and then projected onto a display surface (not shown) to display a display image.

Like the above-described projection display device 200A (see fig. 15), the projection display device 200B having the above-described configuration is excellent in polarization separation characteristics with respect to oblique incident light, can improve light use efficiency, can reduce luminance unevenness, and can improve image quality of a display image.

As shown in fig. 17, the projection display device 200C according to the third specific example of the present embodiment includes a light source 210, a polarization beam splitter 230, a reflective liquid crystal display element 240, a lens 250, and a light absorber 260, but does not include the PS converter 220.

In the projection display device 200C, the light of the unpolarized light emitted from the light source 210 is directly incident on the polarization beam splitter 230 disposed obliquely at an angle of 45 °. The polarization beam splitter 230 reflects a component of the unpolarized light, i.e., the first polarized light (S-polarized light), and emits the component toward the reflective liquid crystal display element 240 at an emission angle of 45 °. On the other hand, the component of the second polarized light (P polarized light) among the unpolarized light incident on the polarization beam splitter 230 is transmitted through the polarization beam splitter 230 and is incident on the light absorber 260. Since the component of the second polarized light (P polarized light) is almost absorbed by the light absorber 260, unnecessary second polarized light (P polarized light) can be suppressed from entering other optical systems in the projection display device 200C.

The reflective liquid crystal display element 240 modulates and reflects a component of the first polarized light (S polarized light) incident from the polarization beam splitter 230, generates second polarized light (P polarized light) representing a display image, and emits the second polarized light (P polarized light) toward the polarization beam splitter 230. The second polarized light (P polarized light) is amplified by the lens 250 through the polarization beam splitter 230, and then projected onto a display surface (not shown) to display a display image.

In the projection display device 200C having the above configuration, the PS converter 220 is not provided, and therefore, the component of the second polarized light (P polarized light) among the unpolarized light emitted from the light source 210 is not used by the light absorber 260 for displaying the display image. Thus causing the light amount of the displayed image to be reduced by about half. However, since the cost and the installation space required for the PS converter 220 can be reduced and the number of components of the projection display device 200C can be reduced, there is an advantage in that the cost of the projection display device 200C can be reduced and the projection display device 200C can be miniaturized.

As described above, a specific example of the projection display device 200 using the reflective wire grid polarizer 1 according to the present embodiment as the polarization beam splitter 230 is described. The projection display device is not limited to the specific example of the projection display device 200 shown in fig. 15 to 17, and the components and arrangement of the projection display device may be appropriately changed or other components may be appropriately provided according to the required performance or the like.

<5 > Vehicle >

Next, a vehicle including the image display device according to the present embodiment will be described.

The vehicle (not shown) according to the present embodiment includes: the projection display device having the wire grid polarizing element 1 according to the present embodiment described above. The vehicle may be a vehicle provided with a projection display device, and may be various vehicles such as a general passenger car, a light car, a bus, a truck, a racing car, a vehicle for construction process, and other large vehicles, and may be various vehicles such as a motorcycle, an electric car, a magnetic levitation train, and a vehicle for amusement facilities.

The vehicle according to the present embodiment can project and display a display image on a display surface (for example, a display surface 5 shown in fig. 14) provided on the vehicle by the polarizing element 1 and the projection display device. The display surface is preferably a semi-transparent plate such as a windshield, side glass, rear glass, or a combination plate of a vehicle. However, the display surface is not limited to the example described above, and may be a surface of various components, parts, in-vehicle devices, or the like provided on the vehicle if the display surface is a surface of an object on which an image can be projected and displayed.

The projection display device provided in the vehicle according to the present embodiment is, for example, a projection display device 200 having the head-up display device 100 shown in fig. 14 or the polarization beam splitter 130 shown in fig. 15 to 17. However, the present invention is not limited to the above-described examples, and the projection display device may be a projector mounted on a vehicle, a car navigation system device, a terminal device having an image display function, or any other image display device as long as it is a device capable of projecting or displaying an image.

As described above, in the head-up display device 100, as shown in fig. 14, sunlight may enter the head-up display device 100 from outside the vehicle through the windshield (display surface 5). The display element 3 may be degraded or malfunction due to heat of the sunlight or the like. Therefore, the above-described hybrid wire grid polarizing element 1 is provided in the head-up display device 100 for the purpose of preventing sunlight from entering the display element 3. Since the polarizing element 1 has a hybrid structure with high thermal conductivity, heat dissipation and heat resistance are excellent. Therefore, the polarizing element 1 can block sunlight entering the head-up display device 100 from the outside to prevent the sunlight from reaching the display element 3, and therefore, failure and breakage of the display element 3 can be prevented. Further, since the polarizing element 1 is excellent in heat dissipation and heat resistance, breakage of the polarizing element 1 itself can be prevented.

Similarly, when the projection display device 200 shown in fig. 15 to 17 is installed in a vehicle, the polarizing element 1 used as the polarizing beam splitter 230 can block sunlight from the outside, and therefore, malfunction and breakage of other components such as the reflective liquid crystal display element 240 can be prevented. Further, breakage of the polarizing element 1 itself, which is excellent in heat dissipation and heat resistance, can be prevented.

As described above, the projection display device provided in the vehicle according to the present embodiment can obtain more excellent polarization characteristics (such as a solar light blocking performance and a polarization separation characteristic) by the polarizing element 1, and can also realize excellent heat resistance and durability of the projection display device.

The vehicle is not particularly limited as long as the vehicle includes the projection display device and the polarizing element described above, and other conditions may be appropriately set and changed according to the performance required of the vehicle.

<6 > Organic Material (photo-curable acrylic resin for imprinting) constituting grid Structure

Next, an organic material (imprint photocurable acrylic resin) constituting the grid structure 20 according to the present embodiment will be described.

As a technique for producing a resin optical member having a fine uneven structure, imprint molding of an uncured resin layer composed of an uncured resin composition is widely used. In the imprint molding, the fine concave-convex shape of the master is pressed against the uncured resin layer formed on the substrate, and in this state, the uncured resin layer is cured, and the master is peeled off, whereby the fine concave-convex shape can be molded on the substrate.

In imprint molding, if the thickness (layer thickness) of the uncured resin layer is not uniform when the master is pressed, the peeling force applied when the master is peeled from the cured resin layer (hereinafter referred to as "cured resin layer") becomes non-uniform in the plane of the cured resin layer. In this way, a part of the cured resin layer may be peeled off from the substrate. In addition, the cured resin layer peeled from the substrate remains on the master, and the master cannot be reused. Further, there is a possibility that the fine concave-convex shape transferred to the cured resin layer is deformed when the mother exploit is separated, and the optical characteristics may be degraded due to the fine concave-convex structure.

In addition, in the imprint molding, when the uncured resin composition has low following property to the fine concave-convex shape when the master is pressed, a portion where the fine concave-convex shape of the master is not transferred is generated in the uncured resin layer.

Therefore, in order to make the layer thickness of the uncured resin layer uniform when the master is pressed, and also to improve the following property of the uncured resin composition to the fine uneven shape, a technique of reducing the viscosity of the uncured resin composition has been developed (for example, as described in japanese patent application laid-open No. 2018-125559 and japanese patent No. 4824068).

In order to reduce the viscosity of the uncured resin composition, it is conceivable to increase the content of the monofunctional monomer and the low-viscosity difunctional monomer in the resin composition.

However, when the content of the monofunctional monomer and the low-viscosity difunctional monomer is increased, there is a problem that the heat resistance of the cured resin layer is lowered.

Accordingly, an object of the present embodiment is to provide a photocurable acrylic resin for imprinting which reduces the viscosity of an uncured resin composition and is excellent in heat resistance of the cured resin composition.

The photocurable acrylic resin for imprinting according to the present embodiment is an uncured resin composition. The photocurable acrylic resin for imprinting according to the present embodiment is composed of a photopolymerization component and a photopolymerization initiator. The photopolymerizable component according to the present embodiment is one of the acrylic polymerizable compounds described above. The photopolymerization initiator according to the present embodiment is a substance for polymerizing a photopolymerization component, and corresponds to the above-described photopolymerization initiator.

<6.1. Composition of photopolymerizable component >

Next, the composition of the photopolymerizable component of the photocurable acrylic resin for imprinting according to the present embodiment will be described. The photopolymerizable component according to this embodiment contains at least a resin (a) and a resin (B). The photopolymerizable component according to the present embodiment may contain one or both of the resin (C) and the resin (D) in addition to the resin (a) and the resin (B). The photopolymerizable component according to the present embodiment may be composed of only the resin (a) and the resin (B), may be composed of only the resin (a), the resin (B) and the resin (C), may be composed of only the resin (a), the resin (B) and the resin (D), and may be composed of only the resin (a), the resin (B), the resin (C) and the resin (D). The resins (a) to (D) are described below.

The resin (A) is (octahydro-4, 7-methylene-1H-indene-1, 5 subunit) bis (methylene) diacrylate. That is, the resin (a) is a difunctional acrylate monomer represented by the following chemical formula (II). As the resin (A), for example, KAYARAD R-684 from Kayarad Co., ltd.

[ Chemical formula 1]

The resin (A) has a viscosity of 100 to 250 mPas at 25 ℃. The viscosity was the viscosity of a liquid using a rotational viscometer and a vibration viscometer according to JIS Z8803. Viscosity is measured, for example, using a conical plate in a Brookfield viscometer manufactured by the company english-hong-refiner.

The resin (B) is a difunctional acrylate monomer having a viscosity of 10 mPas or less at 25 ℃. The resin (B) is preferably a difunctional acrylate monomer having a viscosity of 3 mPas or more at 25 ℃. The resin (B) is a structurally soft difunctional acrylate monomer. The term "structurally soft" means a structure in which the molecules are easily moved, bent, and stretched when heated. The resin (B) may be a difunctional acrylate monomer bonded to an acryl group at both ends of a linear structure composed of a hydrocarbon group or a difunctional acrylate monomer bonded to an acryl group at both ends of a linear structure having an ether bond. Here, the hydrocarbon group is, for example, one or more selected from the group consisting of an alkyl group, an alkylene group, and an alkynyl group.

The difunctional acrylate monomer to which the acryl groups are bonded at both ends of the straight-chain structure composed of the hydrocarbon groups, for example, may be a difunctional acrylate monomer represented by the following chemical formula (I). In the chemical formula (I), n is preferably an integer of 1 to 9, more preferably an integer of 6 to 9, and still more preferably 6 or 9.

CH ₂＝CHCOO(CH ₂)nOOCCH＝CH ₂…(I)

In the case where n is 6 in the above chemical formula (I), that is, in the case where the resin (B) is 1, 6-hexanediol diacrylate, the resin (B) has a viscosity of 6.5 mPas at 25 ℃. In addition, in the case where n is 9 in the above chemical formula (I), that is, in the case where the resin (B) is 1, 9-nonanediol diacrylate, the resin (B) has a viscosity of 8 mPas at 25 ℃.

The difunctional acrylate monomer having an ether bond and bonded to the acryl group at each of both ends of the linear structure may be, for example, dipropylene glycol diacrylate (DPGDA).

The resin (C) is preferably an acrylate monomer having a viscosity of 10 mPas or less at 25 ℃. The resin (C) is preferably an acrylate monomer having a viscosity of 1 mPas or more at 25 ℃. In addition, the resin (C) is preferably a structurally rigid acrylate monomer. The term "hard" as used herein means a structure in which molecules are not easily moved, bent, and stretched when heated. The resin (C) may be, for example, an acrylate monomer having a cyclic structure composed of only a single bond and a cyclic structure composed of one or both of a single bond and multiple bonds (for example, a benzene ring). In addition, the number of acryl groups of the resin (C) is not particularly limited, but the resin (C) is, for example, a monofunctional acrylate monomer.

The resin (C) may be, for example, isobornyl acrylate.

In the case where the resin (C) is isobornyl acrylate, the resin (C) has a viscosity of 9.5 mPas at 25 ℃.

The resin (D) is preferably a trifunctional or higher acrylate monomer. The resin (D) is preferably an acrylate monomer having six functions or less. The resin (D) is preferably a trifunctional or higher hexafunctional or lower acrylate monomer. The resin (D) may be, for example, one or more selected from the group consisting of trimethylolpropane triacrylate (TMPTA), dipentaerythritol hexaacrylate (DPHA), and multifunctional polyester acrylate. As the polyfunctional polyester acrylate, for example, "M-9050" manufactured by Toyama Synthesis Co., ltd.

When the resin (D) is trimethylolpropane triacrylate (TMPTA), the resin (D) has a viscosity of 70 mPas to 80 mPas at 25 ℃. When the resin (D) is dipentaerythritol hexaacrylate (DPHA), the resin (D) has a viscosity of 5000 mPas to 10000 mPas. When the resin (D) is "M-9050", the resin (D) has a viscosity of 6000 mPas to 14000 mPas.

<6.2. Content of each resin in the photopolymerization component as a whole >

Next, the content of each resin in the entire photopolymerizable component according to the present embodiment will be described. In this embodiment, the content of the resin (a) is 20 mass% or more and 40 mass% or less with respect to the entire photopolymerizable component. The total content of the resin (a) and the resin (B) relative to the entire photopolymerizable component is preferably 50 mass% or more, more preferably 60 mass% or more. The total content of the resin (A) and the resin (B) relative to the entire photopolymerizable component is 70 mass% or less. The total content of the resin (a) and the resin (B) with respect to the entire photopolymerizable component is preferably 50 mass% or more and 70 mass% or less, more preferably 60 mass% or more and 70 mass% or less.

The total content of the resin (B) and the resin (C) relative to the entire photopolymerizable component is preferably 40 mass% or more, more preferably 50 mass% or more, and still more preferably 59 mass% or more. The total content of the resin (B) and the resin (C) relative to the entire photopolymerizable component is preferably 70 mass% or less. The total content of the resin (B) and the resin (C) with respect to the entire photopolymerizable component may be 40 mass% or more and 70 mass% or less, preferably 50 mass% or more and 70 mass% or less, and more preferably 59 mass% or more and 70 mass% or less.

Further, the content of the resin (D) relative to the entire photopolymerizable component is preferably more than 0 mass%, more preferably more than 1 mass%. The content of the resin (D) relative to the entire photopolymerizable component is preferably 20 mass% or less, more preferably 10 mass% or less. The content of the resin (D) relative to the entire photopolymerizable component may be more than 0 mass%, 20 mass% or less, preferably more than 1 mass%, 20 mass% or less, and more preferably more than 1 mass% or 10 mass% or less.

<6.3 Photopolymerization initiator >

Next, a photopolymerization initiator according to the present embodiment will be described. The photopolymerization initiator according to the present embodiment is, for example, an acyl phosphine oxide-based photopolymerization initiator or an alkyl benzophenone-based photopolymerization initiator. As the photopolymerization initiator, for example, "Irgacure819" manufactured by IGM RESINS B.V. can be used.

When the content of the entire photopolymerization component in the photocurable acrylic resin for imprinting is 100% by mass, the content of the photopolymerization initiator is preferably 0.5% by mass or more, more preferably 1% by mass or more. In the photocurable acrylic resin for imprinting, when the content of the entire photopolymerization component is 100% by mass, the content of the photopolymerization initiator is preferably 3% by mass or less. When the content of the entire photopolymerization component in the photocurable acrylic resin for imprinting is 100% by mass, the content of the photopolymerization initiator is preferably 0.5% by mass or more and 3% by mass or less, more preferably 1% by mass or more and 3% by mass or less.

<6.4. Viscosity of photo-curable acrylic resin for imprinting >

Next, the viscosity of the photocurable acrylic resin for imprinting according to the present embodiment will be described. The viscosity of the photocurable acrylic resin for imprinting at 25℃is preferably 5 mPas or more, based on the relationship between the contents of the resin (A), the resin (B), the resin (C) and the resin (D) shown in the above 6.2. The viscosity of the photocurable acrylic resin for imprinting at 25℃may be 35 mPas or less, preferably 25 mPas or less, and more preferably 20 mPas or less. The viscosity of the photocurable acrylic resin for imprinting at 25℃may be 5 to 35 mPas, preferably 5 to 25 mPas, and more preferably 5 to 20 mPas.

<6.5. YI value of cured product of photo-curable acrylic resin for imprinting >

Next, a value YI (Yellow Index) of a cured product obtained by irradiating light (for example, ultraviolet rays) to the photocurable acrylic resin for imprinting according to the present embodiment will be described. YI value was calculated based on JIS K7373:2006 "Plastics-yellowness and method for obtaining yellowness (Plastics-Determination of yellowness index AND CHANGE of yellowness index)". YI value is calculated from measurement results using an ultraviolet-visible-near-infrared spectrophotometer V-770 manufactured by Japanese Specification Co., ltd. Specifically, in the ultraviolet-visible near-infrared spectrophotometer V-770, the transmittance of the cured product of light in the wavelength region of 380nm to 800nm at the time of 0 ° incidence was measured using a D65 light source. Then, as to the measurement result, hue calculation was performed by software, whereby X, Y, Z of XYZ color system was calculated. The calculated X, Y, Z of the XYZ color system was substituted into the following formula (3) shown in JIS K7373:2006 to calculate YI values.

YI＝100×(1.2985X-1.1335Z)/Y…(3)

The YI value of the cured product of the photocurable acrylic resin for imprinting according to the present embodiment is preferably 0 or more after the cured product is kept at 120 ℃ for 500 hours. After the cured product of the photocurable acrylic resin for imprinting is kept at 120℃for 500 hours, the YI value of the cured product may be3 or less, preferably 2.5 or less, and more preferably 2 or less. After the cured product of the photocurable acrylic resin for imprinting is held at 120 ℃ for 500 hours, the YI value of the cured product may be 0 to 3, preferably 0 to 2.5, and more preferably 0 to 2.

<6.6. Average transmittance of cured product of photo-curable acrylic resin for imprinting >

Next, the average transmittance of the cured product of the photocurable acrylic resin for imprinting according to the present embodiment with respect to light will be described. The average transmittance is calculated by measuring the transmittance every 1nm in a wavelength region of 430nm to 680nm, and simply averaging the obtained 251 pieces of measurement data. The transmittance is measured, for example, using an ultraviolet-visible-near-infrared spectrophotometer V-770 manufactured by Japanese Specification Co., ltd.

After the cured product of the photocurable acrylic resin for imprinting according to the present embodiment is held at 120 ℃ for 500 hours, the average transmittance of the cured product with respect to light in a wavelength region of 430nm to 680nm may be 91% or more, preferably 92% or more. After the cured product of the photocurable acrylic resin for imprinting is kept at 120℃for 500 hours, the average transmittance of the cured product with respect to light in a wavelength region of 430nm to 680nm may be 94% or less. After the cured product of the photocurable acrylic resin for imprinting is maintained at 120℃for 500 hours, the average transmittance of the cured product with respect to light in a wavelength region of 430nm to 680nm may be 91% to 94%, and preferably 92% to 94%.

The difference in average transmittance of the cured product of the photocurable acrylic resin for imprint according to the present embodiment with respect to light in the wavelength region of 430nm to 680nm (i average transmittance before holding-average transmittance after holding) may be 0.0% or more before and after holding at 120 ℃ for 500 hours. The difference in average transmittance of the cured product of the photocurable acrylic resin for imprinting with respect to light in a wavelength region of 430nm to 680nm (i average transmittance before holding-average transmittance after holding) before and after holding at 120 ℃ for 500 hours may be 0.5% or less, preferably 0.3% or less, and more preferably 0.2% or less. The difference in average transmittance of the cured product of the photocurable acrylic resin for imprinting with respect to light in a wavelength region of 430nm to 680nm (i the average transmittance before holding-the average transmittance after holding) before and after holding at 120 ℃ for 500 hours may be 0.0% to 0.5%, preferably 0.0% to 0.3%, more preferably 0.0% to 0.2%.

The cured product of the photocurable acrylic resin for imprinting according to the present embodiment may have an average transmittance of 90% or more, preferably 91% or more with respect to light in a wavelength region of 430nm to 510nm after being held at 120 ℃ for 500 hours. After the cured product of the photocurable acrylic resin for imprinting is kept at 120℃for 500 hours, the average transmittance of the cured product with respect to light in a wavelength region of 430nm to 510nm may be 94% or less. After the cured product of the photocurable acrylic resin for imprinting is maintained at 120℃for 500 hours, the average transmittance of the cured product with respect to light in a wavelength region of 430nm to 510nm may be 90% to 94%, preferably 91% to 94%.

The difference in average transmittance of the cured product of the photocurable acrylic resin for imprint according to the present embodiment with respect to light in the wavelength region of 430nm to 510nm (i average transmittance before holding-average transmittance after holding) may be 0.0% or more before and after holding at 120 ℃ for 500 hours. The difference in average transmittance of the cured product of the photocurable acrylic resin for imprinting with respect to light in a wavelength region of 430nm to 510nm (i average transmittance before holding-average transmittance after holding) before and after holding at 120 ℃ for 500 hours may be 1.2% or less, preferably 0.7% or less, and more preferably 0.5% or less. The difference in average transmittance of the cured product of the photocurable acrylic resin for imprinting with respect to light in a wavelength region of 430nm to 510nm (i the average transmittance before holding-the average transmittance after holding) may be 0.0% to 1.2%, preferably 0.0% to 0.7%, more preferably 0.0% to 0.5%, before and after holding at 120 ℃ for 500 hours.

<6.7. Storage modulus of cured product of photo-curable acrylic resin for imprinting >

Next, the storage modulus of the cured product of the photocurable acrylic resin for imprinting will be described. Storage modulus refers to a component that is stored inside an object among energy generated by external force and strain. That is, the storage modulus represents the hardness of the cured product. The greater the storage modulus, the stiffer the cured product. The storage modulus is measured, for example, by using DMA7100 manufactured by Hitachi High technology (High-Tech), inc. For example, a sheet of the cured product may be cut into pieces 20mm in the longitudinal direction and 3mm in the transverse direction, and in the stretching mode, the temperature is raised at 5 ℃/min at a constant frequency (1 Hz), and the storage modulus at 25℃to 300℃is measured.

The storage modulus of the cured product of the photocurable acrylic resin for imprint according to the present embodiment at 30℃may be 1.6X10 ⁹ Pa or more, preferably 2.0X10 ⁹ Pa or more, and more preferably 2.2X10 ⁹ Pa or more. The cured product of the photocurable acrylic resin for imprinting at 30℃may have a storage modulus of 2.5X10 ⁹ Pa or less. The storage modulus of the cured product of the photocurable acrylic resin for imprinting at 30℃may be 1.6X10 ⁹ Pa to 2.5X10 ⁹ Pa, preferably 2.0X10 ⁹ Pa to 2.5X10 ⁹ Pa, and more preferably 2.2X10 ⁹ Pa to 2.5X10 ⁹ Pa.

The storage modulus of the cured product of the photocurable acrylic resin for imprint according to the present embodiment at 120℃may be 3.9X10 ⁸ Pa or more, preferably 6.0X10 ⁸ Pa or more, and more preferably 7.0X10 ⁸ Pa or more. The cured product of the photocurable acrylic resin for imprinting at 120℃may have a storage modulus of 2.5X10 ⁹ Pa or less. The storage modulus of the cured product of the photocurable acrylic resin for imprinting at 120℃may be 3.9X10 ⁸ Pa to 2.5X10 ⁹ Pa, preferably 6.0X10 ⁸ Pa to 2.5X10 ⁹ Pa, and more preferably 7.0X10 ⁸ Pa to 2.5X10 ⁹ Pa.

The storage modulus of the cured product of the photocurable acrylic resin for imprint according to the present embodiment at 130℃may be 3.1X10 ⁸ Pa or more, preferably 5.5X10 ⁸ Pa or more, and more preferably 7.0X10 ⁸ Pa or more. The cured product of the photocurable acrylic resin for imprinting at 130℃may have a storage modulus of 2.5X10 ⁹ Pa or less. The storage modulus of the cured product of the photocurable acrylic resin for imprinting at 130℃may be 3.1X10 ⁸ Pa to 2.5X10 ⁹ Pa, preferably 5.5X10 ⁸ Pa to 2.5X10 ⁹ Pa, and more preferably 7.0X10 ⁸ Pa to 2.5X10 ⁹ Pa.

The storage modulus of the cured product of the photocurable acrylic resin for imprint according to the present embodiment at 140℃may be 2.6X10 ⁸ Pa or more, preferably 5.0X10 ⁸ Pa or more, and more preferably 6.0X10 ⁸ Pa or more. The cured product of the photocurable acrylic resin for imprinting at 140℃may have a storage modulus of 2.5X10 ⁹ Pa or less. The storage modulus of the cured product of the photocurable acrylic resin for imprinting at 140℃may be 2.6X10 ⁸ Pa to 2.5X10 ⁹ Pa, preferably 5.0X10 ⁸ Pa to 2.5X10 ⁹ Pa, and more preferably 6.0X10 ⁸ Pa to 2.5X10 ⁹ Pa.

The change rate of the storage modulus of the cured product at 120 ℃ relative to the storage modulus of the cured product at 30 ℃ (storage modulus at 120 ℃ per storage modulus at 30 ℃. Times.100%) may be 17% or more, preferably 30% or more, more preferably 40% or more. The rate of change of the storage modulus of the cured product at 120 ℃ relative to the storage modulus of the cured product at 30 ℃ (storage modulus at 120 ℃ per storage modulus at 30 ℃. Times.100%) may be 100% or less. The change rate of the storage modulus of the cured product at 120 ℃ relative to the storage modulus of the cured product at 30 ℃ (storage modulus at 120 ℃ per storage modulus at 30 ℃. Times.100%) may be 17% to 100%, preferably 30% to 100%, more preferably 40% to 100%.

The change rate of the storage modulus of the cured product at 130 ℃ relative to the storage modulus of the cured product at 30 ℃ (storage modulus at 130 ℃ per storage modulus at 30 ℃. Times.100%) may be 14% or more, preferably 27% or more, more preferably 33% or more. The rate of change of the storage modulus of the cured product at 130 ℃ relative to the storage modulus of the cured product at 30 ℃ (storage modulus at 130 ℃ per storage modulus at 30 ℃. Times.100%) may be 100% or less. The change rate of the storage modulus of the cured product at 130 ℃ relative to the storage modulus of the cured product at 30 ℃ (storage modulus at 130 ℃ per storage modulus at 30 ℃. Times.100%) may be 14% to 100%, preferably 27% to 100%, more preferably 33% to 100%.

The change rate of the storage modulus of the cured product at 140 ℃ relative to the storage modulus of the cured product at 30 ℃ (storage modulus at 140 ℃ per storage modulus at 30 ℃. Times.100%) may be 11% or more, preferably 25% or more, more preferably 30% or more. The rate of change of the storage modulus of the cured product at 140 ℃ relative to the storage modulus of the cured product at 30 ℃ (storage modulus at 140 ℃ per storage modulus at 30 ℃ x 100%) may be 100% or less. The change rate of the storage modulus of the cured product at 140 ℃ relative to the storage modulus of the cured product at 30 ℃ (storage modulus at 140 ℃ per storage modulus at 30 ℃. Times.100%) may be 11% to 100%, preferably 25% to 100%, more preferably 30% to 100%.

<6.8. Glass transition temperature Tg of cured product of photo-curable acrylic resin for imprinting >

Next, the glass transition temperature Tg of the cured product of the photocurable acrylic resin for imprinting will be described. The glass transition temperature Tg can be measured, for example, by using DMA7100 manufactured by Hitachi Ltd. For example, the measurement can be performed by cutting a sheet of the cured product into pieces 20mm in the longitudinal direction and 3mm in the transverse direction, heating the sheet at a constant frequency (1 Hz) at 5 ℃/min in the stretching mode, and confirming the maximum value of the loss tangent tan delta at 25 to 300 ℃.

The glass transition temperature Tg of the cured product of the photocurable acrylic resin for imprinting according to the present embodiment may be 115 ℃ or higher, preferably 140 ℃ or higher, and more preferably 170 ℃ or higher. The glass transition temperature Tg of the cured product of the photocurable acrylic resin for imprinting may be 185℃or lower. The glass transition temperature Tg of the cured product of the photocurable acrylic resin for imprinting may be 115 ℃ to 185 ℃, preferably 140 ℃ to 185 ℃, and more preferably 170 ℃ to 185 ℃.

<6.9 Effect of photo-curable acrylic resin for imprinting >

As described above, the photocurable acrylic resin for imprinting according to the present embodiment contains the resin (a). Thus, the photocurable acrylic resin for imprinting according to the present embodiment can improve the heat resistance of the cured product of the photocurable acrylic resin for imprinting.

The photocurable acrylic resin for imprinting according to the present embodiment contains a resin (B) having a viscosity of 10mpa·s or less at 25 ℃. This can reduce the viscosity of the photocurable acrylic resin for imprinting according to the present embodiment. Further, the resin (B) is preferably a difunctional acrylate monomer bonded to an acryl group at both ends of a linear structure composed of a hydrocarbon group or a difunctional acrylate monomer bonded to an acryl group at both ends of a linear structure having an ether bond. This can further reduce the viscosity of the photocurable acrylic resin for imprinting. The resin (B) is a difunctional acrylate monomer represented by the above chemical formula (I), and in the chemical formula (I), n is preferably an integer of 1 to 9. This can further reduce the viscosity of the photocurable acrylic resin for imprinting. The resin (B) is a difunctional acrylate monomer represented by the above chemical formula (I), and in the chemical formula (I), n is preferably an integer of 6 to 9. This can further reduce the viscosity of the photocurable acrylic resin for imprinting. The resin (B) is a difunctional acrylate monomer represented by the above chemical formula (I), and in the chemical formula (I), n is preferably an integer of 6 or 9. This can further reduce the viscosity of the photocurable acrylic resin for imprinting.

The photocurable acrylic resin for imprinting according to the present embodiment preferably further contains a resin (C) having a viscosity of 10mpa·s or less at 25 ℃. This can further reduce the viscosity of the photocurable acrylic resin for imprinting according to the present embodiment. In the present embodiment, the resin (C) is preferably an acrylic monomer having a viscosity of 10mpa·s or less at 25 ℃ and being structurally hard. This can further reduce the viscosity of the photocurable acrylic resin for imprinting according to the present embodiment and further improve the heat resistance of the cured product of the photocurable acrylic resin for imprinting. In addition, the resin (C) is preferably a monofunctional acrylate monomer. This can terminate the reaction of the end of the polymer in the polymerization reaction (curing reaction) of the imprint photocurable acrylic resin. Therefore, deterioration of the cured product (polymer) of the photocurable acrylic resin for imprinting from the terminal group can be suppressed. In addition, the resin (C) is preferably isobornyl acrylate. This can further reduce the viscosity of the photocurable acrylic resin for imprinting according to the present embodiment, and can further improve the heat resistance of the cured product of the photocurable acrylic resin for imprinting.

The photocurable acrylic resin for imprinting according to the present embodiment preferably further contains a resin (D) which is an acrylate monomer having a trifunctional or higher functionality. As a result, the photocurable acrylic resin for imprinting according to the present embodiment can increase the crosslinking density during curing, can further increase the heat resistance of the cured product of the photocurable acrylic resin for imprinting, and can suppress the decrease in storage modulus at high temperatures. Further, the resin (D) is preferably one or more selected from the group consisting of trimethylolpropane triacrylate, dipentaerythritol hexaacrylate, and multifunctional polyester acrylate. This can further improve the heat resistance of the cured product of the photocurable acrylic resin for imprinting.

As described above, in the photocurable acrylic resin for imprint according to the present embodiment, the content of the resin (a) is 20 mass% or more and 40 mass% or less with respect to the entire photopolymerizable component, and the total content of the resin (a) and the resin (B) is 70 mass% or less with respect to the entire photopolymerizable component. Thus, the photocurable acrylic resin for imprinting according to the present embodiment can achieve both low viscosity and improvement in heat resistance of the cured product.

Since the imprint photocurable acrylic resin according to the present embodiment has a low viscosity, the thickness (layer thickness) of the imprint photocurable acrylic resin layer when the master 60 is pressed against the imprint photocurable acrylic resin (organic material) can be made uniform in the nanoimprint step S12 (fig. 11). Thus, the peeling force applied when the master 60 is peeled from the cured layer of the imprint photocurable acrylic resin can be made uniform in the plane. Therefore, the cured layer of the photocurable acrylic resin for imprinting can be prevented from being peeled off from the substrate 10. Therefore, the cured layer of the photocurable acrylic resin for imprinting can be prevented from remaining on the master 60, and the master 60 can be reused. Further, since the peeling force can be made uniform in the plane, the situation in which the fine uneven shape of the layer transferred to the cured imprint photocurable acrylic resin is deformed when the master 60 is peeled off can be avoided. Therefore, the deterioration of the optical characteristics due to the fine uneven shape of the cured product of the imprint photocurable acrylic resin can be suppressed. Therefore, in the case of manufacturing the grid structure 20 from the cured product of the imprint-photocurable acrylic resin, the deterioration of the polarization characteristics possessed by the grid structure 20 can be suppressed.

In addition, since the imprinting-photocurable acrylic resin according to the present embodiment has a low viscosity, in the nanoimprinting step S12, the ability of the imprinting-photocurable acrylic resin to follow the fine uneven shape of the master 60 when the master 60 is pressed against the imprinting-photocurable acrylic resin can be improved. Therefore, in the nanoimprint step S12, the fine uneven shape of the master 60 can be sufficiently transferred to the layer of the imprint-light curable acrylic resin.

In addition, since the imprint photocurable acrylic resin according to the present embodiment has a low viscosity, air bubbles can be prevented from being mixed into the imprint photocurable acrylic resin in the nanoimprint step S12. This can avoid a situation in which a part of the fine uneven shape is broken by air bubbles in the cured product of the photocurable acrylic resin for imprinting. Therefore, when the grid structure 20 is manufactured from the cured product of the photo-curable acrylic resin for imprinting, breakage of the ridge portions 22 of the grid structure 20 can be suppressed.

The cured product of the photocurable acrylic resin for imprinting according to the present embodiment is excellent in heat resistance. Therefore, even when an optical material (for example, the grid structure 20 of the wire grid polarizing element 1) is manufactured from a cured product of an imprint photocurable acrylic resin, and when a heating treatment such as vapor deposition is further performed on the optical material, it is possible to suppress a decrease in optical characteristics possessed by the optical material.

For example, since the cured product of the photocurable acrylic resin for imprinting according to the present embodiment is excellent in heat resistance, the YI value of the cured product of the photocurable acrylic resin for imprinting becomes 3 or less after the cured product is kept at 120 ℃ for 500 hours. Therefore, by producing an optical material from a cured product of the photocurable acrylic resin for imprinting, yellowing of the optical material can be suppressed and transparency can be maintained even when the optical material is subjected to further heat treatment such as vapor deposition.

Further, since the cured product of the photocurable acrylic resin for imprinting according to the present embodiment is excellent in heat resistance, the cured product of the photocurable acrylic resin for imprinting has an average transmittance of 91% or more with respect to light in a wavelength region of 430nm to 680nm after being held at 120 ℃ for 500 hours. Therefore, by producing the optical material from the cured product of the photocurable acrylic resin for imprinting, the average transmittance of the optical material with respect to light in the wavelength region can be maintained high even when the optical material is subjected to a heat treatment such as vapor deposition.

Further, since the cured product of the photocurable acrylic resin for imprinting according to the present embodiment is excellent in heat resistance, the cured product of the photocurable acrylic resin for imprinting has an average transmittance of 90% or more with respect to light in a wavelength region of 430nm to 510nm after being held at 120 ℃ for 500 hours. Therefore, by producing the optical material from the cured product of the photocurable acrylic resin for imprinting, the average transmittance of the optical material with respect to light in the wavelength region can be maintained high even when the optical material is subjected to a heat treatment such as vapor deposition.

The storage modulus of the cured product of the photocurable acrylic resin for imprinting at 30℃is preferably 1.6X10- ⁹ Pa or more. In this way, in the nanoimprint step S12 (fig. 11), the situation in which the fine uneven shape of the layer transferred to the cured imprint photocurable acrylic resin is deformed when the master 60 is peeled off can be further avoided. Therefore, the deterioration of the optical characteristics due to the fine uneven shape of the cured product of the imprint photocurable acrylic resin can be further suppressed. Therefore, in the case of manufacturing the grid structure 20 from the cured product of the imprint-photocurable acrylic resin, the deterioration of the polarization characteristics possessed by the grid structure 20 can be further suppressed.

Further, since the cured product of the photocurable acrylic resin for imprinting according to the present embodiment is excellent in heat resistance, the storage modulus of the cured product at 120 ℃ is 3.9x10 ⁸ Pa or more. Therefore, by producing the optical material from the cured product of the photocurable acrylic resin for imprinting, deformation of the optical material can be further suppressed even when the optical material is subjected to a heat treatment such as vapor deposition. Therefore, the deterioration of the optical characteristics of the optical material can be more suppressed.

As described above, the reflective film 30 is deposited on the grid structure 20 when the wire grid polarizing element 1 is manufactured. At the time of vapor deposition of the reflective film 30, the grid structure 20 is heated. Here, when the heat resistance of the grid structure 20 is low, there is a problem that the grid structure 20 is deformed during vapor deposition of the reflective film 30, and the polarization characteristics are degraded.

However, the cured product of the photocurable acrylic resin for imprinting according to the present embodiment is excellent in heat resistance. Therefore, by manufacturing the grid structure 20 from the cured product of the imprint-curable acrylic resin, even when the reflective film 30 is deposited, yellowing of the grid structure 20 and deformation of the grid structure 20 can be suppressed, and the average transmittance of the grid structure 20 with respect to light in the wavelength region of 430nm to 680nm and light in the wavelength region of 430nm to 510nm can be maintained high. Therefore, the deterioration of the polarization characteristics of the grid structure 20 can be further suppressed.

Further, as described above, the viscosity of the photopolymerizable acrylic resin photopolymerizable component for imprinting at 25℃is preferably 35 mPas or less. In this way, in the nanoimprint step S12, the thickness of the layer of the imprint photocurable acrylic resin when the master 60 is pressed against the imprint photocurable acrylic resin can be made more uniform, the ability of the imprint photocurable acrylic resin to follow the fine uneven shape of the master 60 can be further improved, and the incorporation of bubbles into the imprint photocurable acrylic resin can be further suppressed.

As described above, in the photocurable acrylic resin for imprinting according to the present embodiment, the total content of the resin (B) and the resin (C) with respect to the entire photopolymerizable component is preferably 50 mass% or more and 70 mass% or less. This can further reduce the viscosity of the photocurable acrylic resin for imprinting according to the present embodiment. For example, by setting the total content of the resin (B) and the resin (C) to 59 mass% or more and 70 mass% or less with respect to the entire photopolymerizable component, the photocurable acrylic resin for imprinting at 25 ℃ can have a viscosity of 25mpa·s or less.

As described above, in the photocurable acrylic resin for imprinting according to the present embodiment, the content of the resin (D) with respect to the entire photopolymerizable component is preferably more than 0 mass% and 20 mass% or less. This can further improve the heat resistance of the photocurable acrylic resin for imprinting according to the present embodiment. For example, the storage modulus of the cured product of the imprint-curable acrylic resin at 120 ℃ can be set to 6.2X10 ⁸ Pa or more, the storage modulus of the cured product of the imprint-curable acrylic resin at 130 ℃ can be set to 5.5X10 ⁸ Pa or more, and the storage modulus of the cured product of the imprint-curable acrylic resin at 140 ℃ can be set to 5.0X10 ⁸ Pa or more. Further, the change rate of the storage modulus of the cured product at 120 ℃ with respect to the storage modulus of the cured product at 30 ℃ can be set to 30% or more, the change rate of the storage modulus of the cured product at 130 ℃ with respect to the storage modulus of the cured product at 30 ℃ can be set to 27% or more, and the change rate of the storage modulus of the cured product at 140 ℃ with respect to the storage modulus of the cured product at 30 ℃ can be set to 23% or more. The glass transition temperature of the cured product of the photocurable acrylic resin for imprinting can be 125 ℃ or higher.

<6.10. Other Components >

The photocurable acrylic resin for imprinting may contain other components (additives) within a range that does not impair the effect shown in the above 6.9. As other components, for example, antioxidants, phosphors, plasticizers, ultraviolet absorbers, defoamers, thixotropic agents, polymerization inhibitors, mold release agents, particles of metal oxides, and the like.

Examples

Next, an embodiment of the present invention will be described. However, the examples described below are specific examples for illustrating the structure, effects, and the like of the polarizing element 1 according to the present embodiment described above, and the present invention is not limited to the examples described below.

<1 > Results of verification of transmittance and polarization separation characteristics for oblique incident light

As an example of the present invention, the wire grid polarizing element 1 according to the present embodiment was evaluated by creating a model of the wire grid polarizing element 1 described above and simulating various characteristics thereof. In addition, for comparison with the embodiment of the present invention, a model of the wire grid polarizing element according to the conventional example was also prepared, and simulation and evaluation were performed in the same manner. In the following description, for convenience of explanation, in the embodiments and the conventional examples, the same reference numerals and numerals are given to reference numerals indicating components of the polarizing element (the substrate 10, the grid structure 20, the base portion 21, the ridge portion 22, the reflective film 30, etc.) and numerals indicating various dimensions of these components.

In the following description, reference numerals indicating various dimensions and the like of the polarizing element 1 to be used are described as follows.

P: spacing of the raised strips 22

W _T: width of top of ridge 22 (ridge top width)

W _M: width of the central position in the height direction of the ridge 22 (ridge central width)

W _B: width of bottom of ridge 22 (grid bottom width)

W _MAX: maximum width of reflective film 30 wrapping ridge 22 (maximum width of grid)

H: height of the raised strip 22

Hx: height of a portion of the side surface 22b of the ridge portion 22 covered with the reflective film 30

Dt: the thickness of the reflective film 30 covering the front ends 22a of the raised strips 22 (the front end thickness of the reflective film 30)

Ds: the thickness of the reflective film 30 covering the side surface 22b of the ridge portion 22 (the side surface thickness of the reflective film 30)

Rc: coating ratio of side surface 22b of ridge 22 coated with reflective film 30

Rr: opening ratio of side surface 22b of ridge 22 covered with reflective film 30

Θ: incident angle of incident light

Lambda: wavelength of incident light

(PRIOR ART EXAMPLE 1)

First, with reference to fig. 18, conventional example 1 will be described.

A model of the polarizing element 1 according to conventional example 1 was produced as shown in fig. 18 (a). The polarizing element 1 according to conventional example 1 includes a glass substrate 10 and a grid structure 20 made of an ultraviolet curable resin (acrylic resin). The grid structure 20 includes: a base portion 21 provided along the surface of the substrate 10, and a plurality of ridge portions 22 protruding from the base portion 21 and formed in a lattice shape. The cross-sectional shape of the ridge 22 is rectangular, and is not a head-thin shape. The reflective film 30 covering the ridge portions 22 is an Al film. The reflective film 30 is formed so as to cover the entirety of the front end 22a and one side surface 22b of the ridge portion 22 and a part of the base portion 21. But the reflective film 30 does not completely cover the other side 22b of the ridge portion 22. As described above, the reflective film 30 of conventional example 1 is formed so as to be biased toward only one side of the ridge portion 22, and the other side of the ridge portion 22 is opened without being covered with the reflective film 30.

The dimensions and shapes of the respective portions of the model of the polarizing element 1 according to conventional example 1 are as follows.

P：144nm

W _T：32.5nm

W _B：32.5nm

W _MAX：55nm

H：220nm

Hx:220nm (one side), 0nm (the other side)

Dt：35nm

Ds:22.5nm (maximum)

Rc:100% (one side), 0% (other side)

Rr:0% (one side), 100% (other side)

θ：0°～+60°

λ：430～680nm

Then, regarding the model of the polarizing element 1 according to conventional example 1 manufactured as described above, the incident angle θ was changed and simulated, and the transmission axis transmittance (Tp), the reflection axis reflectance (Rs), and tp×rs required as a Polarizing Beam Splitter (PBS) were calculated, respectively. The incident angle θ is 0 ° to +60°. As the values of Tp and Rs, an average value of a plurality of values of Tp and Rs calculated for the incident light of each wavelength λ by changing the wavelength λ of the incident light in the range of 430 to 680nm is used. The relationship between Tp, rs, tp×rs and θ calculated in the above manner is shown in graphs (b) to (d) of fig. 18.

As shown in fig. 18, in conventional example 1, the reflective film 30 is biased to one side of the ridge portion 22, and the coating ratio Rc on that side is 100%. Therefore, as the incident angle θ increases, rs gradually increases, and conversely, tp significantly decreases, so tp×rs also significantly decreases. For example, in the range of θ.ltoreq.45°, tp falls below 76% and tp×rs falls below 68%. Therefore, it is found that when the polarizing element 1 according to conventional example 1 is used as a polarizing beam splitter, polarization separation characteristics (tp×rs characteristics) are poor particularly for oblique incident light having a large incident angle θ of 45 ° or more, and the tp×rs characteristics required for the polarizing beam splitter cannot be obtained.

(PRIOR ART EXAMPLE 2)

Next, with reference to fig. 19, conventional example 2 will be described.

A model of the polarizing element 1 according to conventional example 2 was produced as shown in fig. 19 (a). The model of conventional example 2 is the same as that of conventional example 1 described above. However, in conventional example 2, as the incident angle θ, both the incident angle (θ=0° to +60°) in the +direction incident from the oblique direction to one side of the ridge portion 22 and the incident angle (θ=0° to-60 °) in the-direction incident from the oblique direction to the other side of the ridge portion 22 are used.

The dimensions and shapes of the respective portions of the model of the polarizing element 1 according to conventional example 2 are as follows.

P：144nm

W _T：32.5nm

W _B：32.5nm

W _MAX：55nm

H：220nm

Hx:220nm (one side), 0nm (the other side)

Dt：35nm

Ds:22.5nm (maximum)

Rc:100% (one side), 0% (other side)

Rr:0% (one side), 100% (other side)

θ：0°～+60°、0°～-60°

λ：430～680nm

Then, the model of the polarizing element 1 according to conventional example 2 fabricated as described above was simulated by changing the incident angle θ, and the transmission axis transmittance (Tp), the reflection axis reflectance (Rs), and tp×rs required as a Polarizing Beam Splitter (PBS) were calculated, respectively. At this time, tp, rs, tp×rs are calculated for each of the case where the incident angle θ is in the +direction and the case of the-direction. As the values of Tp and Rs, an average value of a plurality of values of Tp and Rs calculated for the incident light of each wavelength by changing the wavelength λ of the incident light in the range of 430 to 680nm is used. The relationship between Tp, rs, tp×rs and θ calculated in the above manner is shown in graphs (b) to (d) of fig. 19.

As shown in fig. 19, in conventional example 2, the reflection film 30 is biased to the side of the ridge portion 22, and the coating ratio Rc on the side is 100% as in conventional example 1. As a result, as shown in fig. 19 (b), it was confirmed that in conventional example 2, as in conventional example 1, the incidence angle θ of oblique incident light from the +direction was significantly decreased as Tp (+) was increased. In conventional example 2, the absolute value of the negative incidence angle θ is also larger as the incidence of oblique incidence light from the direction is larger, tp (-) is decreased, and the decrease degree of Tp (-) is smaller than that of Tp (+).

Specifically, in conventional example 2, the absolute value of θ was in the range of 30 ° to 60 °, the difference between Tp (+) and Tp (-) was 5% or more, and the difference between tp×rs (+) and tp×rs (-) was 4% or more. From this result, it was confirmed that in conventional example 2, the polarization characteristic of the polarization element 1 was asymmetric left and right depending on whether the incident direction of the oblique incident light was the +direction or the-direction.

As in conventional example 2 described above, it is known that, when the difference in Tp is large due to the difference in incidence direction of oblique incident light (for example, +45° is different from-45 °), the observer can recognize the difference in brightness of the display image, and the difference becomes inappropriate as a video state. Further, it is found that when the polarizing element 1 according to conventional example 2 is used as a polarizing beam splitter, polarization separation characteristics (tp×rs characteristics) are poor particularly for oblique incident light having a large incident angle θ of 45 ° or more, and that the tp×rs characteristics required by the polarizing beam splitter cannot be obtained.

(PRIOR ART EXAMPLE 3)

Next, with reference to fig. 20, conventional example 3 will be described.

A model of the polarizing element 1 according to conventional example 3 was produced as shown in fig. 20 (a). The polarizing element 1 according to conventional example 3 includes a glass substrate 10 and a grid structure 20 made of an ultraviolet curable resin (acrylic resin). The grid structure 20 includes: a base portion 21 provided along the surface of the substrate 10, and a plurality of ridge portions 22 protruding from the base portion 21 and formed in a lattice shape. The cross-sectional shape of the ridge 22 is rectangular, and is not a head-thin shape. The reflective film 30 covering the ridge portions 22 is an Al film. The reflective film 30 is formed so as to cover most (about 85%) of the front ends 22a and the side surfaces 22b of the ridge portions 22. As described above, the reflective film 30 of conventional example 3 covers most of the front ends 22a and both side surfaces 22b of the ridge portions 22. The reflective film 30 of conventional example 3 has two corners having edges at both the left and right ends of the top of the reflective film 30, unlike the convex shape with an arc of a circle as in the reflective film 30 of the polarizing element 1 according to the present embodiment described above.

The dimensions and shapes of the respective portions of the model of the polarizing element 1 according to conventional example 3 are as follows.

P：140nm

W _T：35nm

W _B：35nm

W _MAX：65nm

H：230nm

Hx：196nm

Dt：30nm

Ds:15nm (maximum)

Rc：85％

Rr：15％

θ：0°～+60°

λ：430～680nm

Next, as for the model of the polarizing element 1 according to conventional example 3 manufactured as described above, tp, rs, tp×rs were calculated by changing the incident angle θ and performing simulation in the same manner as in conventional example 1 described above. The incident angle θ is 0 ° to +60°. The relationship between Tp, rs, tp×rs and θ calculated in this way is shown in graphs of fig. 20 (b) to (d).

As shown in fig. 20, in conventional example 3, the coating method is different from that of conventional example 1, but the reflective film 30 coats most of the side surfaces 22b of both sides of the ridge portion 22, and the coating ratio Rc is as large as 85%. Therefore, in conventional example 3, as in conventional example 1, as the incident angle θ is larger, rs gradually increases, but Tp significantly decreases, so tp×rs also significantly decreases. For example, in the range of θ >45 °, tp falls below 73% and tp×rs falls below 65%. Therefore, it is found that when the polarizing element 1 according to conventional example 3 is used as a polarizing beam splitter, polarization separation characteristics (tp×rs characteristics) are poor particularly for oblique incident light having a large incident angle θ of 45 ° or more, and the tp×rs characteristics required for the polarizing beam splitter cannot be obtained.

Example 1

Next, embodiment 1 of the present invention will be described with reference to fig. 21 and 22.

A model of the polarizing element 1 according to example 1 was produced as shown in fig. 21 (a). The polarizing element 1 according to example 1 includes a glass substrate 10 and a grid structure 20 made of an ultraviolet curable resin (acrylic resin). The grid structure 20 includes: a base portion 21 provided along the surface of the substrate 10, and a plurality of ridge portions 22 protruding from the base portion 21 and formed in a lattice shape. The cross-sectional shape of the ridge 22 is trapezoidal, and is tapered as it becomes thinner toward the tip 22a of the ridge 22.

The reflective film 30 covering the ridge portions 22 in example 1 is an Al film. The reflective film 30 is formed so as to cover the top ends 22a of the ridge portions 22 and the upper sides of both side surfaces 22 b. However, the reflective film 30 does not cover the lower portions of the side surfaces 22b of the ridge portions 22 and the base portion 21. The coating rate Rc of the both side surfaces 22b of the ridge portion 22 coated with the reflective film 30 is 40%. As described above, the reflective film 30 of example 1 surrounds the tops (upper sides of the distal ends 22a and the side surfaces 22 b) of the ridge portions 22 in an arc shape. The surface of the reflective film 30 is substantially elliptical having an arc that bulges outward, and bulges in the width direction (X direction) of the ridge portion 22.

As a result, the grid (the structure in which the ridge portions 22 and the reflective film 30 are combined) according to example 1 has the above-described special tree shape. The maximum width W _MAX of the special tree-shaped grating (the width of the grating in the most bulged portion of the reflective film 30) is equal to or greater than the width W _B of the bottom of the ridge portion 22 (the width of the ridge portion 22 at a height position 20% above the bottom of the ridge portion 22).

The dimensions and shapes of the respective portions of the model of the polarizing element 1 according to example 1 are as follows.

P：144nm

W _T：19nm

W _M：32.5nm

W _B：46nm

W _MAX：55nm

H：220nm

Hx：99nm

Dt:35nm (maximum)

Ds:22.5nm (maximum)

Rc：40％

Rr：60％

θ：0°～+60°

λ：430～680nm

Then, regarding the model of the polarizing element 1 according to example 1 manufactured as described above, the incident angle θ was changed and simulated, and the transmission axis transmittance (Tp), the transmission axis reflectance (Ts), the reflection axis transmittance (Rp), the reflection axis reflectance (Rs), and tp×rs required as a Polarizing Beam Splitter (PBS) were calculated, respectively. The incident angle θ is 0 ° to +60°. As the value Tp, rs, ts, rp, an average value of a plurality of values Tp, ts, rp, rs calculated for the incident light of each wavelength λ by changing the wavelength λ of the incident light in the range of 430 to 680nm is used. Further, the Contrast Ratio (CR) of the transmitted light was also calculated by dividing the transmission axis transmittance (Tp) by the transmission axis reflectance (Ts) (cr=tp/Ts).

The relationship between Tp, rs, ts, rp, CR, tp ×rs and λ calculated in the above manner is shown in the table of fig. 21 (b) and the graphs of fig. 21 (c) to (d). The relationship between Tp, rs, tp×rs and θ calculated in the above manner is shown in graphs (a) to (c) of fig. 22.

In the table of fig. 21 b, the average value of each characteristic value (Tp, rs, ts, rp, CR, tp ×rs) is shown by dividing the plurality of wavelength bands (430 to 510nm, 520 to 590nm, 600 to 680 nm) of the incident light and the entire wavelength band (430 to 680 nm) of the incident light. Fig. 21 shows graphs (c) to (d) and graphs (a) to (c) of fig. 22, which show average values of characteristic values (Tp, rs, ts, rp, CR, tp ×rs) in the entire wavelength band (430 to 680 nm) of the incident light. In addition, the graphs (a) to (c) of fig. 22 show the characteristic values (Tp (+), tp (-), rs (+), rs (-), tp×rs (+), tp×rs (-)) of the conventional example 2 for comparison with example 1.

As shown in fig. 21 (a), in the model of the polarizing element 1 of example 1, the reflective film 30 covers the top of the ridge portion 22 and opens the bottom of the ridge portion 22, and the coating ratio Rc is 40%. Therefore, the grid (the structure in which the ridge portions 22 and the reflective film 30 are combined) of embodiment 1 has the above-described special tree shape. The grid having the special tree structure of example 1 was excellent in transmittance and polarization separation characteristics for oblique incident light having a wide range of incident angles θ.

Therefore, as shown in fig. 21, in example 1, regardless of the wavelength λ, tp is 80% or more and Rs is 90% or more, and high Tp and Rs can be obtained. As a result, it was found that tp×rs was 72% or more, and excellent tp×rs characteristics were obtained. Further, it is also known that the contrast CR is excellent in contrast of 100 or more regardless of the wavelength λ. Therefore, it is understood that example 1 can obtain a good polarization characteristic for obliquely incident light, compared with the above-described conventional examples 1 and 2.

As shown in fig. 22, in example 1, tp having a very high value of 78% or more is ensured in a wide range of the incidence angle θ of 0 ° to 60 °. As a result, it was found that a high tp×rs of 73% or more can be ensured for oblique incident light having a wide range of incident angles θ (30 ° to 60 °), and that excellent polarization separation characteristics (tp×rs characteristics) are provided. Especially in the case of θ=45°, tp is a value very high up to 87%, and tp×rs is also a value very high up to 78%. From this, it is understood that the polarizing element 1 of example 1 can exhibit remarkably excellent transmittance and polarization separation characteristics for oblique incident light having an incident angle θ of 45 ° and the periphery thereof.

As is clear from the comparison result between example 1 and conventional example 2 shown in fig. 22, in conventional example 2, tp and tp×rs decrease as the incident angle θ increases, and in particular, tp and tp×rs decrease sharply in the range of θ >45 °. In contrast, in example 1, even if θ is large, the drop in Tp and tp×rs is suppressed, and a high value can be maintained. In particular, when θ=45°, example 1 can obtain Tp and tp×rs higher by 6% or more than in the case of incidence in the +direction of conventional example 2, and Tp and tp×rs higher by 10% or more than in the case of incidence in the-direction of conventional example 2. As described above, in example 1, when θ=45°, the highest transmittance (transmittance Tp) and tp×rs characteristics were obtained.

In addition, regarding the reflectance Rs of the reflection axis, example 1 can obtain a high reflectance without significant errors compared with the conventional examples 1 and 2.

In addition, example 1 is superior to conventional examples 1 and 2 in terms of tp×rs characteristics required as a Polarizing Beam Splitter (PBS), and the highest tp×rs characteristics can be obtained when the incident angle θ=45°. In addition, in the range of the incidence angle θ=30° to 60 °, example 1 can obtain better characteristics than those of the conventional examples 1 and 2, and the characteristics of oblique incidence light having a wide range of incidence angle θ are better than those of the conventional examples 1 and 2, tp×rs. In example 1, the characteristic of tp×rs was balanced well for oblique incident light having an incident angle θ in the range of 45 ° ± 15 °. Therefore, when the polarizing element 1 according to example 1 is used as a polarizing beam splitter and an image is projected, the balance of brightness of the display image is good from the viewpoint of an observer, and the display image is good even in a video state.

As described above, when the polarizing element 1 according to example 1 is used as a polarizing beam splitter, it is found that the P-polarized light is particularly excellent in the transmittance (transmittance Tp) and polarization separation characteristics (tp×rs characteristics) for oblique light having a wide range of incidence angles θ of 30 ° to 60 °, in particular, for oblique light having an incidence angle θ of 45 °. Thus, it can be said that the polarization separation characteristics required by the polarization beam splitter can be sufficiently satisfied for oblique incident light.

Further, as for the contrast CR of the transmitted light (cr=tp/Ts), it is found that in example 1, an excellent contrast CR of 100 or more was obtained.

Example 2

Next, embodiment 2 of the present invention will be described with reference to fig. 23.

A model of the polarizing element 1 according to example 2 was produced as shown in fig. 23 (a). The model of example 2 is different from the model of example 1 in the shape of the ridge portion 22 and the coating method of the reflective film 30. The cross-sectional shape of the ridge portion 22 in example 2 is triangular, and is a tapered shape that tapers toward the tip 22a of the ridge portion 22.

The reflective film 30 covering the ridge portions 22 in example 2 is an Al film. The reflective film 30 is formed so as to cover the top ends 22a of the ridge portions 22 and the upper sides of both side surfaces 22 b. However, the reflective film 30 does not cover the lower portions of the side surfaces 22b of the ridge portions 22 and the base portion 21. The coating rate Rc of the side surfaces 22b of the convex strip 22 coated by the reflective film 30 is 45%. As described above, the reflective film 30 of example 2 surrounds the tops (upper sides of the distal ends 22a and the side surfaces 22 b) of the ridge portions 22 in an arc shape. The surface of the reflective film 30 is substantially elliptical having an arc that bulges outward, and bulges in the width direction (X direction) of the ridge portion 22. As described above, the grid (the structure in which the ridge portions 22 and the reflective film 30 are combined) according to example 2 has the above-described special tree shape as in example 1.

The dimensions and shapes of the respective portions of the model of the polarizing element 1 according to example 2 are as follows.

P：140nm

W _T：10nm

W _B：40nm

W _MAX：41nm

H：230nm

Hx：103.5nm

Dt:50nm (maximum)

Ds:17nm (maximum value)

Rc：45％

Rr：55％

θ：0°～+60°

λ：430～680nm

Then, regarding the model of the polarizing element 1 according to example 2 produced in the above manner, the incident angle θ was changed and simulated, and the transmission axis transmittance (Tp), the reflection axis reflectance (Rs), and tp×rs required as a Polarizing Beam Splitter (PBS) were calculated, respectively. As the values of Tp and Rs, an average value of a plurality of values of Tp and Rs calculated for the incident light of each wavelength by changing the wavelength λ of the incident light in the range of 430 to 680nm is used. The relationship between Tp, rs, tp×rs and θ calculated in the above manner is shown in graphs (b) to (d) of fig. 23.

As shown in fig. 23 (a), the grid (structure of the ridge portions 22 and the reflective film 30) of example 2 has the above-described special tree shape as in example 1, and therefore is excellent in transmittance and polarization separation characteristics for oblique incident light having a wide range of incident angles θ.

Therefore, as shown in fig. 23, in example 2, a high value Tp of 74% or more is ensured in a wide range of the incidence angle θ of 0 ° to 45 °. It is found that, particularly in the case of θ=30° and 45 °, a high Tp of 88% or more can be ensured, and a high tp×rs of 74% or more can be ensured, and excellent polarization separation characteristics (tp×rs characteristics) are obtained. From this, it is clear that the polarizing element 1 of example 2 can exhibit remarkably excellent transmittance and polarization separation characteristics for oblique incident light having an incident angle θ of 30 ° to 45 °.

As described above in example 2, it was found that even when the shape of the ridge portions 22 of the grid structure 20 is different from that of example 1, good transmittance and polarization separation characteristics can be obtained as compared with conventional examples 1 to 3. However, when the incidence angle θ was 60 °, tp and tp×rs characteristics were superior to those of example 2 in example 1.

Example 3

Next, embodiment 3 of the present invention will be described with reference to fig. 24. In example 3, the relationship between the height H of the ridge portion 22 and the polarization characteristic of the polarizing element 1 was verified.

A model of the polarizing element 1 according to example 3 was produced as in fig. 24 (a). The model of example 3 is the same as the model of example 1 described above. The cross-sectional shape of the ridge 22 is trapezoidal, and is tapered as it becomes thinner toward the tip 22a of the ridge 22. The grid (structure of the ridge portions 22 and the reflective film 30) of example 3 has the above-described special tree shape as in example 1. In example 3, the coating rate Rc was maintained at 45% and the height H of the ridge portion 22 was changed stepwise in the range of 100 to 220 nm.

The dimensions and shapes of the respective portions of the model of the polarizing element 1 according to example 3 are as follows.

P：144nm

W _T：19nm

W _M：32.5nm

W _B：46nm

W _MAX：55nm

H：100～220nm

Hx：45～99nm

Dt:35nm (maximum)

Ds:22.5nm (maximum)

Rc：45％

Rr：55％

θ：+45°

λ：430～680nm

Then, with respect to the model of the polarizing element 1 according to example 3 produced as described above, tp, rs, tp×rs were calculated by changing the height H of the ridge portion 22 and performing simulation. The incident angle θ was +45°. As the values of Tp and Rs, an average value of a plurality of values of Tp and Rs calculated for the incident light of each wavelength λ by changing the wavelength λ of the incident light in the range of 430 to 680nm is used. Further, the contrast CR of the transmitted light is also calculated by dividing Tp by Ts.

The relationship between Tp, rs, tp×rs, CR and H calculated in the above manner is shown in graphs (b) to (e) of fig. 24.

As shown in fig. 24, it is clear that in order to improve various characteristics (Tp, tp×rs, CR) of the polarization element 1 with respect to 45 ° oblique incident light, the height H of the ridge portion 22 is preferably 160nm or more, more preferably 180nm or more, and particularly preferably 220nm or more.

Specifically, as shown in fig. 24 (b), if H is 160nm or more and Tp is 80% or more, high transmittance is obtained, which is preferable. Further, if H is 180nm or more, tp of 85% or more can be obtained, which is more preferable. Further, if H is 220nm or more, 87% or more of Tp can be obtained, which is particularly preferable.

Further, as to the characteristic of tp×rs, as shown in fig. 24 (d), if H is 160nm or more, excellent tp×rs of 70% or more can be obtained, which is preferable. Further, if H is 180nm or more, tp×Rs of 75% or more can be obtained, which is more preferable. Further, if H is 220nm or more, tp×Rs of 77% or more can be obtained, which is particularly preferable.

As shown in fig. 24 (e), the contrast CR may be equal to or greater than 40 as long as H is equal to or greater than 100 nm. When H is 160nm or more, excellent CR of 150 or more can be obtained, and thus it is preferable. Further, if H is 180nm or more, excellent CR of 250 or more can be obtained, and thus more preferable. Further, when H is 220nm or more, excellent CR of 500 or more can be obtained, and thus it is particularly preferable.

Example 4

Next, embodiment 4 of the present invention will be described with reference to fig. 25. In example 4, the relationship between the thickness Dt of the reflective film 30 covering the distal ends 22a of the ridge portions 22 (the distal end thickness Dt of the reflective film 30) and the polarization characteristics of the polarizing element 1 was examined.

A model of the polarizing element 1 according to example 4 was produced as in fig. 25 (a). The model of example 4 is the same as the model of example 1 described above. The cross-sectional shape of the ridge 22 is trapezoidal, and is tapered as it becomes thinner toward the tip 22a of the ridge 22. The grid (structure of the ridge portions 22 and the reflective film 30) of example 4 has the above-described special tree shape as in example 1. In example 4, the thickness Dt of the front end of the reflective film 30 was changed stepwise in the range of 5 to 35 nm.

The dimensions and shapes of the respective portions of the model of the polarizing element 1 according to example 4 are as follows.

P：144nm

W _T：19nm

W _M：32.5nm

W _B：46nm

W _MAX：55nm

H：220nm

Hx：99nm

Dt: 5-35 nm (maximum)

Ds:22.5nm (maximum)

Rc：45％

Rr：55％

θ：+45°

λ：430～680nm

Next, regarding the model of the polarizing element 1 according to example 4 produced in the above manner, tp, rs, tp×rs, and CR were calculated by changing the tip thickness Dt of the reflective film 30 and performing simulation. The incident angle θ was +45°. The relationship between Tp, rs, tp×rs, CR and Dt calculated in the above manner is shown in graphs of fig. 25 (b) to (e).

As shown in fig. 25, it is clear that the thickness Dt of the front end of the reflection film 30 is preferably 5nm or more, more preferably 15nm or more, in order to improve various characteristics (Tp, tp×rs, CR) of the polarizing element 1 with respect to 45 ° oblique incident light.

Specifically, as shown in fig. 25 (b), if Dt is 5nm or more and Tp is 85% or more, high transmittance is obtained, which is preferable. In addition, as shown in fig. 25 (c), rs is preferably at least 85% because it is preferable that Dt is at least 5nm, since it can give a high reflectance.

Further, as shown in fig. 25 (d), if Dt is 15nm or more, excellent tp×rs of 78% or more can be obtained, which is more preferable with respect to tp×rs characteristics.

Further, as shown in fig. 25 (e), if Dt is 5nm or more, a contrast CR is preferably 100 or more, since it is possible to obtain an excellent CR. Further, if Dt is 15nm or more, excellent CR of 250 or more can be obtained, which is more preferable.

Example 5

Next, embodiment 5 of the present invention will be described with reference to fig. 26. In example 5, the relationship between the thickness Ds of the reflection film 30 covering the side surface 22b of the ridge portion 22 (the side surface thickness Ds of the reflection film 30) and the polarization characteristics of the polarizing element 1 was examined.

A model of the polarizing element 1 according to example 5 was produced as in fig. 26 (a). The model of example 5 is the same as the model of example 1 described above. The cross-sectional shape of the ridge 22 is trapezoidal, and is tapered as it becomes thinner toward the tip 22a of the ridge 22. The grid (structure of the ridge portions 22 and the reflective film 30) of example 5 has the above-described special tree shape as in example 1. In example 5, the side surface thickness Ds of the reflective film 30 was changed stepwise in the range of 5 to 35 nm.

The dimensions and shapes of the respective portions of the model of the polarizing element 1 according to example 5 are as follows.

P：144nm

W _T：19nm

W _M：32.5nm

W _B：46nm

W _MAX：20～80nm

H：220nm

Hx：99nm

Dt:35nm (maximum)

Ds: 5-35 nm (maximum)

Rc：45％

Rr：55％

θ：+45°

λ：430～680nm

Next, with respect to the model of the polarizing element 1 according to example 5 produced in the above manner, tp, rs, tp×rs, CR were calculated by changing the side thickness Ds of the reflective film 30 and performing simulation. The incident angle θ was +45°. The relationships between Tp, rs, tp×rs, CR and Dt calculated in the above manner are shown in graphs (b) to (e) of fig. 26.

As shown in fig. 26, it is clear that, in order to improve various characteristics (Tp, tp×rs, CR) of the polarizing element 1 with respect to 45 ° oblique incident light, the side surface thickness Ds of the reflection film 30 is preferably 10nm to 30nm, more preferably 12.5nm to 25nm, and particularly preferably 15nm to 25 nm.

Specifically, as shown in fig. 26 (b), if Ds is 10nm or more and 30nm or less, tp is 80% or more, and high transmittance is obtained, which is preferable. Further, if Ds is 12.5nm to 25nm, tp is 85% to 85%, and higher transmittance is obtained, which is more preferable. Further, if Ds is 15nm to 20nm, tp is 87% to 87%, and higher transmittance is obtained, which is particularly preferable.

In addition, as shown in fig. 26 (c), rs is preferably 10nm or more, and Rs is 80% or more, since a high reflectance can be obtained. Further, if Ds is 12.5nm or more, rs is 85% or more, and higher reflectance can be obtained, which is more preferable. Further, if Ds is 15nm or more, rs is 87% or more, and a higher reflectance can be obtained, so that it is particularly preferable.

Further, as to the characteristic of Tp×Rs, as shown in FIG. 26 (d), if Ds is 12.5nm or more and 30nm or less, excellent Tp×Rs of 70% or more can be obtained, which is preferable. Further, if Ds is 15nm or more and 25nm or less, excellent Tp×Rs of 76% or more can be obtained, which is more preferable.

As shown in fig. 26 (e), ds is preferably 10nm or more, but if Ds is 12.5nm or more, a superior CR of 50 or more can be obtained. Further, if Ds is 15nm or more, excellent CR of 100 or more can be obtained, which is more preferable.

Example 6

Next, embodiment 6 of the present invention will be described with reference to fig. 27. In example 6, the relationship between the coating ratio Rc of the side surface 22b of the ridge portion 22 coated with the reflective film 30 and the polarization characteristics of the polarizing element 1 was examined.

A model of the polarizing element 1 according to example 6 was produced as in fig. 27 (a). The model of example 6 is the same as the model of example 1 described above. The cross-sectional shape of the ridge 22 is trapezoidal, and is tapered as it becomes thinner toward the tip 22a of the ridge 22. The grid (structure of the ridge portions 22 and the reflective film 30) of example 6 has the above-described special tree shape as in example 1. In example 6, the coating rate Rc was changed stepwise in the range of 20 to 90% by changing the height Hx of the range of the side surface 22b of the ridge portion 22 coated with the reflective film 30.

The dimensions and shapes of the respective portions of the model of the polarizing element 1 according to example 6 are as follows.

P：144nm

W _T：19nm

W _M：32.5nm

W _B：46nm

W _MAX：55nm

H：220nm

Hx：44～198nm

Dt:35nm (maximum)

Ds:22.5nm (maximum)

Rc：20～90％

Rr：80～10％

θ：+45°

λ：430～680nm

Next, the model of the polarizing element 1 according to example 6 produced as described above was simulated with the coating ratio Rc changed, and Tp, rs, tp×rs, and CR were calculated, respectively. The incident angle θ was +45°. The relationships between Tp, rs, tp×rs, CR and Dt calculated in the above manner are shown in graphs (b) to (e) of fig. 27.

As shown in fig. 27, it is clear that, in order to improve various characteristics (Tp, tp×rs, CR) of the polarization element 1 for oblique incident light of 45 °, the coating rate Rc is preferably 25% to 80%, more preferably 30% to 70%, still more preferably 30% to 60%, and particularly preferably 40% to 50%.

Specifically, as to Tp, as shown in fig. 27 (b), if Rc is 25% or more and 80% or less, tp is 75% or more, and high transmittance is obtained, which is preferable. Further, if Rc is 30% or more and 70% or less, tp is 80% or more, and higher transmittance can be obtained, which is more preferable. Further, if Rc is 40% or more and 50% or less, tp is 85% or more, and higher transmittance can be obtained, which is particularly preferable.

In addition, as shown in fig. 27 (c), rs is preferably 20% or more, and Rs is 85% or more, since a high reflectance can be obtained.

Further, as to the characteristic of tp×rs, as shown in fig. 27 (d), if Rc is 25% or more and 80% or less, tp×rs is 70% or more, and excellent characteristic of tp×rs can be obtained, which is preferable. Further, if Rc is 30% or more and 70% or less, tp×rs is 72% or more, and if Rc is 30% or more and 60% or less, tp×rs is 75% or more, more excellent tp×rs characteristics can be obtained, which is more preferable. Further, if Rc is 40% or more and 50% or less, tp×Rs is 77% or more, more excellent Tp×Rs characteristics can be obtained, and thus, it is particularly preferable.

As shown in fig. 27 (e), the contrast CR may be 20% or more Rc, but if Rc is 30% or more, an excellent CR of 100 or more is obtained, which is preferable. Further, if Rc is 40% or more, excellent CR of 200 or more can be obtained, and thus more preferable.

Example 7

Next, embodiment 7 of the present invention will be described with reference to fig. 28. In example 7, the relationship among the thickness Ds of the reflection film 30 (the side surface thickness Ds of the reflection film 30), the incident angle θ, and the polarization characteristics of the polarizing element 1, which covers the side surface 22b of the ridge portion 22, was examined.

A model of the polarizing element 1 according to example 7 was produced as in fig. 28 (a). The model of example 7 is the same as the model of example 1 described above. The cross-sectional shape of the ridge 22 is trapezoidal, and is tapered as it becomes thinner toward the tip 22a of the ridge 22. The grid (structure of the ridge portions 22 and the reflective film 30) of example 7 has the above-described special tree shape as in example 1. In example 7, the side surface thickness Ds of the reflection film 30 was changed stepwise in the range of 17.5 to 25nm and the incident angle θ was changed stepwise in the range of 0 to 60 °.

The dimensions and shapes of the respective portions of the model of the polarizing element 1 according to example 7 are as follows.

P：144nm

W _T：19nm

W _M：32.5nm

W _B：46nm

W _MAX：45nm、55nm、60nm

H：220nm

Hx：99nm

Dt:35nm (maximum)

Ds:17.5nm, 22.5nm, 25nm (maximum)

Rc：45％

Rr：55％

θ：0～+60°

λ：430～680nm

Next, regarding the model of the polarizing element 1 according to example 7 produced in the above manner, tp, rs, tp×rs were calculated by changing the side thickness Ds and the incidence angle θ of the reflective film 30 and performing simulation. The incidence angle θ is changed stepwise every 15 ° in the range of 0 to +60°. The relationship between Tp, rs, tp×rs and Dt calculated in the above manner is shown in graphs (b) to (d) of fig. 28.

As shown in fig. 28, even when the side surface thickness Ds of the reflective film 30 is varied stepwise in the range of 17.5 to 25nm, the polarizing element 1 has excellent polarization characteristics (Tp, rs, tp×rs) for oblique incident light having a wide incident angle θ of 0 ° to +60°. It is found that the polarizing characteristics are very excellent particularly for oblique incident light having an incident angle θ of +45°.

Specifically, as to Tp, as shown in fig. 28 (b), even if Ds varies in the range of 17.5 to 25nm, if θ is in the range of +30° to +60°, tp is 75% or more, and high transmittance can be obtained, which is preferable. Further, if θ is +45°, tp is 85% or more, and the highest transmittance is obtained, which is more preferable.

As shown in fig. 28 (c), rs is preferably 85% or more in a wide range of incidence angle θ of 0 ° to +60°, since high reflectance can be obtained.

Further, as to the characteristic of tp×rs, as shown in fig. 28 (d), even if Ds varies in the range of 17.5 to 25nm, if θ is in the range of +30° to +60°, tp×rs is 70% or more, and excellent characteristic of tp×rs can be obtained, which is preferable. Further, if θ is +45°, tp×rs is 76% or more, and the most excellent tp×rs characteristics can be obtained, which is more preferable. Further, the balance of tp×rs characteristics is good for oblique incident light having an incident angle θ in the range of 45 ° ± 15 °. Therefore, when the polarizing element 1 according to example 7 was used as a polarizing beam splitter to project an image, the balance of brightness of the display image was good as seen from the observer, and the image state was also good.

Example 8

Next, embodiment 8 of the present invention will be described with reference to fig. 29. In example 8, the relationship between the deviation ratio when the reflection film 30 covering the ridge portion 22 is deviated to one side and the polarization characteristic of the polarizing element 1 was examined.

A model of the polarizing element 1 according to example 8 was produced as in fig. 29 (a). The model of example 8 is the same as the model of example 1 described above, except that the reflective film 30 is biased to one side of the ridge portion 22. The cross-sectional shape of the ridge 22 is trapezoidal, and is tapered as it becomes thinner toward the tip 22a of the ridge 22. The grid (structure of the ridge portions 22 and the reflective film 30) of example 8 has the above-described special tree shape as in example 1.

In example 8, regarding the left side surface 22b of the ridge portion 22, the side surface thickness Ds (left side) of the reflection film 30 covering the side surface 22b was set to 22.5nm, the height Hx (left side) of the coating range was set to 99nm, and the coating rate Rc (left side) was set to 45%. On the other hand, the side surface thickness Ds (right side) of the reflection film 30 covering the right side surface 22b of the ridge portion 22 is changed stepwise in the range of 0 to 22.5 nm. At the same time, the height Hx (right side) of the coating range of the right side surface 22b of the ridge 22 is changed stepwise in the range of 0 to 99nm, and the coating rate Rc (right side) is changed stepwise in the range of 0 to 45%. As a result, the maximum width W _MAX of the grating was varied stepwise in the range of 32.5 to 55 nm.

In example 8, as the incidence angle θ, both the incidence angle (θ=0° to +60°) in the +direction of incidence from the oblique direction to the left side of the ridge portion 22 and the incidence angle (θ=0° to-60 °) in the-direction of incidence from the oblique direction to the right side of the ridge portion 22 were used.

The dimensions and shapes of the respective portions of the model of the polarizing element 1 according to example 8 are as follows.

P：144nm

W _T：19nm

W _M：32.5nm

W _B：46nm

W _MAX：32.5nm、37.5nm、47.5nm、55nm

H：220nm

Hx (left): 99nm

Hx (right): 0 to 99nm

Dt:35nm (maximum)

Ds (left): 22.5nm (maximum)

Ds (right): 0nm, 5nm, 10nm, 22.5nm (maximum)

Rc (left): 45%

Rc (right): 0%, 22%, 33%, 45%,

Rr (left): 55%

Rc (right): 100%, 78%, 67%, 55%

Θ (left): 0 to +60°

Θ (right side): 0 to-60 DEG

λ：430～680nm

Next, with respect to the model of the polarizing element 1 according to example 8 produced in the above manner, ds (right side) and Rc (right side) concerning the left side surface 22b of the reflective film 30 were changed and simulated, and Tp, rs, tp×rs, and CR were calculated, respectively. The incidence angle θ is changed stepwise every 15 ° in the range of 0 to +60°. The relationship between Tp, rs, tp×rs, CR and Dt calculated in the above manner is shown in graphs of fig. 29 (b) to (e).

As shown in fig. 29, it is clear that the polarizing element 1 has good polarization characteristics (Tp, rs, tp×rs, CR) even when the reflective film 30 is biased to one side of the ridge portion 22, that is, when the grid is asymmetric left and right.

Specifically, as to Tp, as shown in fig. 29 (b), even when oblique incident light is incident on the grid biased with respect to the reflective film 30 from either the +direction or the-direction, both Tp (+) and Tp (-) become 85% or more, and high transmittance can be obtained on both sides of the grid. In this case, it was confirmed that the difference between Tp (+) and Tp (-) was 3% or less, and that no significant error occurred between Tp (+) and Tp (-) due to the incidence direction of oblique incident light.

In addition, as shown in fig. 29 (c), even when oblique incident light is incident on the grid deviated from the reflective film 30 in either the +direction or the-direction, both of Rs (+) and Rs (-) are 85% or more, and high reflectance can be obtained on both sides of the grid.

Further, as to the tp×rs characteristics, as shown in fig. 29 (d), even when oblique incident light is incident from either the +direction or the-direction to the grid biased with respect to the reflective film 30, tp×rs becomes 75% or more, and excellent tp×rs characteristics can be obtained.

As shown in fig. 29 (e), even when oblique light is incident from either the positive direction or the negative direction on the grid biased with respect to the reflective film 30, the contrast CR is excellent. Further, ds (right side) is preferably 5nm or more, and the coating ratio (left side) is preferably 22% or more, whereby an excellent CR of 100 or more can be obtained. Further, ds (right side) is more preferably 10nm or more, and the coating ratio (left side) is 33% or more, whereby a CR of 150 or more is obtained.

( Verification of the shape of the reflective film: example 9, PREPARATION EXAMPLE 4 )

Next, with reference to fig. 30 and 31, a comparison is made between example 9 of the present invention (the reflective film 30 is in the shape of an arc) and conventional example 4 (the reflective film 30 is in the shape of an angle), and the result of verifying the relationship between the shape of the reflective film 30 covering the ridge portion 22 and the polarization characteristics of the polarizing element 1 will be described.

As shown in fig. 30 and 31, a model of the polarizing element 1 according to example 9 and a model of the polarizing element 1 according to conventional example 4 were produced.

The model of the polarizing element 1 according to example 9 has a special tree shape (see fig. 21, etc.) similar to the model of example 1 described above. The grid of the polarizing element 1 according to example 9 has: the base portion 21, the ridge portion 22 having a trapezoidal cross-sectional shape, and the reflective film 30 covering the top (upper side of the front end 22a and the side surface 22 b) of the ridge portion 22. However, the model of the polarizing element 1 according to example 9 is different from the model of example 1 in the coating ratio Rc of the both side surfaces 22b of the ridge portion 22 coated with the reflective film 30, and the coating ratio Rc of example 9 is 45%. The reflective film 30 of example 9 has a shape of wrapping the tops of the ridge portions 22 in an arc shape. The surface of the reflective film 30 of example 9 is substantially elliptical having an arc that bulges outward, and bulges in the width direction (X direction) of the ridge portion 22. The surface of the reflection film 30 of example 9 has a smoothly curved surface shape, and does not have corner portions or stepped portions. Hereinafter, the reflective film 30 of example 9 is referred to as a circular arc reflective film.

On the other hand, the model of the polarizing element 1 according to conventional example 4 is different in the shape of the reflective film 30 from the model of example 9. The reflective film 30 of conventional example 4 has an angular shape, and has two corners having edges at both the left and right ends of the top of the reflective film 30, unlike the reflective film 30 of example 9 described above, which has a bulged shape with an arc (arc-shaped reflective film). Hereinafter, the reflective film 30 of comparative example 4 is referred to as an angular reflective film. The model of the polarizing element 1 of conventional example 4 corresponds to the wire grid type polarized photon disclosed in the above-mentioned patent document 7.

As described above, in conventional example 4, the shape of the reflection film 30 is different from that in example 9, but the other requirements are the same as those in example 9.

The dimensions of the portions common to the polarizing element 1 of example 9 and conventional example 4 are as follows.

P：144nm

W _T：19nm

W _M：32.5nm

W _B：46nm

W _MAX：55nm

H：220nm

Hx：99nm

Dt:35nm (maximum)

Ds:22.5nm (maximum)

Rc：45％

Rr：55％

θ：0°～+60°

λ：430～680nm

Regarding the model of the polarizing element 1 according to example 9 and conventional example 4 manufactured as described above, tp, rs, and tp×rs were calculated by changing the incident angle θ and performing simulation. The incident angle θ is 0 ° to +60°.

The relationship between Tp, rs, tp×rs and θ calculated in the above manner is shown in graphs (b) to (d) of fig. 30.

As shown in fig. 30, in example 9, tp having a very high value of 78% or more was ensured in a wide range of the incidence angle θ of 0 ° to 60 °. As a result, it was found that a high tp×rs of 73% or more can be ensured for oblique incident light having a wide range of incident angles θ (30 ° to 60 °), and that excellent polarization separation characteristics (tp×rs characteristics) are provided. Especially in the case of θ=45°, tp is a value very high up to 87%, and tp×rs is also a value very high up to 78%. From this, it is understood that the polarizing element 1 of example 9 can exhibit remarkably excellent transmittance and polarization separation characteristics for oblique incident light having an incident angle θ of 45 ° and the periphery thereof.

As is clear from the comparison between example 9 and conventional example 4 shown in fig. 30, in conventional example 4, tp and tp×rs fall down as the incident angle θ increases in the range of θ >30 °, and Tp and tp×rs fall down sharply in the range of θ >45 °.

In contrast, in example 9, in the range of 0 ° or more and θ or less than or equal to 45 °, tp and tp×rs rise instead as θ becomes larger, and high values of Tp and tp×rs can be maintained. In example 9, even if θ is large in the range of 45 ° < θ+.ltoreq.60°, the decrease in Tp and tp×rs is significantly suppressed as compared with conventional example 4, and high values of Tp and tp×rs can be maintained. In particular, in the case where θ=45°, tp and tp×rs higher by 5% or more than those in the case of conventional example 4 can be obtained in example 9. In addition, in the case where θ=60°, tp and tp×rs higher by 7% or more than in the case of conventional example 4 can be obtained in example 9. In example 9, the significantly excellent transmittance (transmittance Tp) and tp×rs characteristics were obtained in the range of a large and wide incident angle θ (30 ° to 60 °, particularly, 45 ° to 60 °).

In addition, regarding Rs, example 9 can obtain high reflectance without significant error compared with conventional example 4.

In addition, example 9 is superior to conventional example 4 in terms of tp×rs characteristics required as a Polarizing Beam Splitter (PBS), and the highest tp×rs characteristics can be obtained when the incident angle θ=45°. In addition, in the range of incidence angle θ=30° to 60 °, example 9 also obtained better characteristics than conventional example 4, and for oblique incidence light having a wide range of incidence angle θ, the characteristics of tp×rs were better than those of conventional example 4. In example 9, the characteristic of tp×rs was balanced well for oblique incident light having an incident angle θ in the range of 45 ° ± 15 °. Therefore, when the polarizing element 1 according to example 9 is used as a polarizing beam splitter and an image is projected, the balance of brightness of the display image is good from the viewpoint of an observer, and the display image is good even in a video state.

As described above, it is found that when the polarizing element 1 is used as the polarizing beam splitter, the transmittance (transmittance Tp) and polarization separation characteristics (tp×rs characteristics) of P-polarized light are particularly excellent for oblique incident light having a wide range of incidence angles θ of 30 ° to 60 °, particularly 45 °, as compared with the conventional example 4. Thus, it can be said that the polarization separation characteristics required by the polarization beam splitter can be sufficiently satisfied for oblique incident light.

As described above, example 9 having the arc-shaped reflective film 30 has a lower dependence on the incident angle θ of the oblique incident light than that of the conventional example 4 having the angle-shaped reflective film 30, and the transmittance of the oblique incident light and the polarization separation characteristic (tp×rs characteristic) as the polarization beam splitter are excellent. The reason for this will be described below with reference to fig. 31.

As shown in fig. 31, the transmittance of incident light in the wire grid polarizing element 1 is basically determined by the ratio (W _G/W _A) of the effective grid width W _A to the gap width W _G. The grid width W _A is a width of 1 reflective film 30 in a direction perpendicular to the direction of the incident light, and the gap width W _G is a width of a gap between two adjacent reflective films 30 in a direction perpendicular to the direction of the incident light. As the width of the reflective film 30 (the width of the metal grid portion) occupied by the 1 pitch of the grid structure 20 is smaller, the incident light reflected by the reflective film 30 having the smaller width is reduced, and thus the transmittance of the incident light is increased.

Here, as shown in fig. 31, a case where the incident light is incident from the oblique direction of the polarizing element 1 (i.e., a case where θ >0 °) is considered. In this case, in example 9 in which the reflection film 30 is of an arc shape, the effective grid width W _A as viewed from the oblique direction is smaller and the gap width W _G as viewed from the oblique direction is larger than in conventional example 4 in which the reflection film 30 is of an angle shape. Therefore, when oblique incident light is incident on the polarizing element 1, the transmittance Tp of example 9 is higher than the transmittance Tp of conventional example 4. As a result, the tp×rs characteristics of example 9 are superior to those of conventional example 4. For example, it is found that the transmittances Tp and tp×rs of example 9 are higher by about 5% than those of conventional example 4 when the incidence angle θ of oblique incident light is 45 °, and that the transmittances Tp and tp×rs of example 9 are higher by about 7% than those of conventional example 4 when θ is 60 ° (see (b) (d) of fig. 30).

For the above reasons, it can be said that example 9 having the circular arc-shaped reflective film 30 has a lower dependence on the incident angle θ of oblique incident light, has a higher transmittance of oblique incident light, and has a higher polarization separation characteristic (tp×rs characteristic) as a polarization beam splitter than conventional example 4 having the angular reflective film 30.

< 2> Results of verification of Heat radiation

Next, the result of verifying the heat radiation performance of the polarizing element 1 will be described by comparing the hybrid wire grid polarizing element 1 made of an inorganic material and an organic material according to the embodiment of the present invention with the film type wire grid polarizing element made of an organic material according to the conventional example.

As described above, according to the wire grid polarizing element 1 of the present embodiment described above, the substrate 10 is made of an inorganic material such as glass having extremely excellent heat resistance. The base portion 21 and the plurality of raised strips 22 of the grid structure 20 directly provided on the substrate 10 are integrally formed of a heat-resistant organic material. As described above, the wire grid polarizer 1 according to the present embodiment is a hybrid type polarizer in which an organic material and an inorganic material are combined. Therefore, considering that the thermal resistance R [ m ² ·k/W ] of the entire polarizing element 1 is small, heat can be efficiently dissipated from the grid structure 20 to the substrate 10, and therefore the heat dissipation is excellent.

On the other hand, the film-type wire grid polarizer of the conventional example is mainly composed of an organic material, and therefore has low heat resistance (at 100 ℃). Further, it is considered that the total thickness of the organic material layer composed of the substrate (base film), the double-sided tape (OCA), and the grid structure is increased, and thus the thermal resistance R of the organic material layer is also increased.

Therefore, the hybrid wire grid polarizer 1 according to the present embodiment is superior to a conventional film-type polarizer (heat resistance: 100 ℃ C.) made of an organic material in heat resistance and heat dissipation, for example, in heat resistance under a high-temperature environment of 200 ℃ C. As a result, the hybrid wire grid polarizer 1 according to the present embodiment can achieve excellent polarization characteristics and can exhibit good heat dissipation characteristics.

Therefore, the practical example of the hybrid wire grid polarizer of the present invention and the film type wire grid polarizer of the conventional example were manufactured, and these thermal resistance R and heat dissipation properties were verified.

Table 1 shows the types of general base materials and the thermal conductivities λW/mK. In table 2, the thicknesses of the layers made of the organic material (PMMA), the thicknesses of the entire layers made of the organic material (PMMA) (total thickness D _ALL), and the thermal resistance R [ m ² ·k/W ] are shown for the hybrid wire grid polarizer 1 according to the embodiment of the present invention and the film type wire grid polarizer according to the conventional example.

TABLE 1

TABLE 2

In the hybrid-type polarizing element 1 according to the embodiment shown in table 2, the base portion 21 and the ridge portion 22 constituting the grid structure 20 are formed of an organic material, and the substrate 10 is formed of an inorganic material. On the other hand, in the film-type polarizing element according to the conventional example, the substrate, the base portion constituting the grid structure, and the double-sided tape for bonding the base portion and the substrate are all formed of an organic material. Here, PMMA (Poly _Methyl_M ethacrylate, polymethyl methacrylate) is used as the organic material. As a result, the total thickness D _ALL of the PMMA material of the hybrid polarizer 1 according to the example was 0.0302[ mm ]. On the other hand, the total thickness D _ALL of the PMMA material of the film type polarizing element according to the conventional example was 0.2552[ mm ], which is far greater than D _ALL of the example.

As shown in Table 1, the thermal conductivity lambda of PMMA was 0.21[ W/mK ]. The thermal resistance R [ m ².K/W ] is obtained by dividing "the thickness D _ALL [ mm ] of the material by" the thermal conductivity lambda [ W/m.K ] "(R= (D _ALL/1000)/lambda). Thus, the thermal resistance R of the grid structure 20 of the hybrid-type polarizing element 1 according to the example was 0.000144[ m ². Multidot.K/W ]. On the other hand, the thermal resistance R of the film-type polarizing element according to the conventional example was 0.001215[ m ². Multidot. K/W ].

Therefore, by using the hybrid-type polarizing element 1 according to the embodiment of the present invention, the value of the thermal resistance R of the grid structure 20 made of PMMA material can be reduced to about 1/8.4 as compared with the film-type polarizing element according to the conventional example. As a result, according to the hybrid-type polarizing element 1 according to the embodiment of the present invention, heat of the grid structure 20 made of an organic material (for example, PMMA) can be efficiently radiated to the outside through the substrate 10 made of an inorganic material having heat resistance and heat radiation properties superior to those of the organic material. Therefore, the hybrid-type polarizing element 1 according to the embodiment of the present invention has extremely excellent heat resistance and heat dissipation properties as compared with the conventional example.

Further, it was also verified that when the polarizing element 1 was irradiated with light of the order of, for example, 5000 lm (lumens) in a projection display device mounted on a projector or the like, the polarizing element 1 was directly provided on the substrate 10, the relationship between the thickness TB of the base portion 21 of the grid structure 20 and the temperature difference Δt between the front and rear surfaces of the base portion 21 was also examined. The verification result is described below. The temperature difference Δt is a temperature difference (Δt=t1-T2) between the temperature T1 of the outermost surface of the base portion 21 (the root of the plurality of raised strips 22) and the temperature T2 of the base portion 21 at the interface between the base portion 21 and the substrate 10.

Fig. 32 is a graph showing the relationship between the wavelength of light and the luminosity function in bright and dark places. The visual acuity K (spectral luminous efficasy, spectral light efficiency) is an index that indicates the intensity of brightness at each wavelength of human eye perceived light by numerical values. That is, visual acuity K is an index representing the perceived light beam [ lm ] per 1W radiation beam of light (electromagnetic waves). The unit of the radiation beam is [ W ], the unit of the light beam (light measuring quantity) is [ lm ], and the unit of the visual acuity K is [ lm/W ]. The visual acuity K varies depending on the wavelength of light (electromagnetic wave), and becomes highest at a wavelength of 555 nm. At this time, the visual acuity Kmax is 683[ lm/W ], and this 683[ lm/W ] is referred to as the maximum visual acuity K _m. The luminosity function V is an index expressed by a ratio of visual acuity K at a certain wavelength to maximum visual acuity K _m (=683 [ lm/W ]) (v=k/K _m). The luminosity function V is a numerical value of 0 to 1.0, and has no unit.

As shown in fig. 32, the brightness perceived by the human eye (visual acuity K, luminosity function V) varies greatly depending on the wavelength of light. In bright places, the human eye perceives most strongly light around wavelength 555nm, and in dark places, light around wavelength 507 nm. Since projectors are used in various places such as bright places and dark places, light of the projector that is brightly perceived by human eyes is light having a wavelength of around 528nm in either bright places or dark places. Therefore, the result of calculating the output power Pw W of the light source of the projector when light having a wavelength of 528nm is irradiated with a brightness (light beam) of 5000 lm from the projector is shown in table 3.

TABLE 3

As described above, in bright spots, the human eye perceives light most strongly around 555 nm. That is, in the curve of the bright standard photometric function shown in the graph of fig. 32, the wavelength that becomes the maximum visual acuity K _m is around 555 nm. The visual acuity K at the wavelength 555nm is the maximum visual acuity K _m =683 [ lm/W ]. According to the graph of FIG. 32, the photometric function V is 0.84 at a wavelength of 528 nm. At a maximum visual acuity K _m at a wavelength of 555nm of 683[ lm/W ], the visual acuity K at a wavelength of 528nm is 573.7[ lm/W ] (683 [ lm/W ]. Times.0.84.apprxeq.573.7 [ lm/W ]). Therefore, when 5000 lm is irradiated from the projector, the output power Pw of the light source of the projector (electromagnetic beam irradiated from the light source) becomes 8.7W (5000 lm/573.7 lm/w≡8.7W).

Considering that the output power Pw of the light source of the projector is 8.7[ w ], light with a wavelength of 528nm is irradiated to the vertical (Y direction): 10[ mm ] X horizontal (X direction): 20[ mm ] in the case of a polarizing element 1 of rectangular plate shape. In this case, when the surface area of the polarizing element 1 is a [ m ² ], the output power Pw 'per unit area in the surface of the polarizing element 1 becomes Pw' [ W/m ²]＝Pw[W]/A[m² ]. In this case, it is evaluated how the temperature difference Δt between the temperature T1 of the outermost surface of the base portion 21 and the temperature T2 of the interface of the base portion 21 and the substrate 10 changes according to the thickness TB of the base portion 21. At this time, the thickness TB of the base portion 21 is varied within a range of 0.010 to 0.255[ mm ]. The relationship between the thickness TB of the base 21 and the temperature difference Δt is shown in table 4. Furthermore, PMMA is used as a material of the grid structure 20 of the polarizing element 1. The thermal conductivity lambda of PMMA was 0.21[ W/mK ]. The temperature difference Δt is calculated as follows.

Temperature difference Δtk=thermal resistance rm ² ·k/w×output power Pw 'per unit area'

[W/m²]

Here, since the temperature difference Δt is a relative temperature, the temperature difference Δt [ K ] =the temperature difference Δt [ °c ]. Thus, with respect to the unit of Δt, 1[K ] =1 [ °c ].

TABLE 4

As shown in table 4, in examples 1to 10 of the present invention, a hybrid wire grid polarizing element 1 composed of an inorganic material (substrate 10) and an organic material (grid structure 20) was used. On the other hand, the conventional example uses a film type wire grid polarizing element composed of an organic material.

The thickness TB (=0.255 mm) of the base portion of the conventional example shown in table 4 is "total thickness D _ALL (see table 2) as PMMA material" in the film type wire grid polarizer. In view of the thickness of a film or a double-sided tape (OCA) that is generally circulated, a structure example of a wire grid polarizing element of the thinnest film type has been illustrated. Therefore, in the film type wire grid polarizer formed by bonding a plurality of films and double-sided tape, it is considered that the total thickness D _ALL is less likely to be reduced than in the conventional example shown in table 4. In contrast, the hybrid wire grid polarizer 1 of examples 1 to 10 has a structure in which the grid structure 20 made of an organic material (PMMA) is directly formed on the substrate 10 made of an inorganic material. Therefore, in examples 1 to 10, as shown in table 4, the thickness TB of the base portion 21 (total thickness D _ALL which is a PMMA material) can be made much thinner than in the conventional example.

As is clear from table 4, in the film-type wire grid polarizer of the conventional example, the thickness TB of the base portion (=total thickness D _ALL as PMMA material) was 0.255[ mm ], and therefore the temperature difference Δt between the front and back of the base portion was 52.9 ℃, and as a result, exceeded 50 ℃. Further, since the internal space of the projector is sealed, the peripheral temperature of the wire grid polarizer or the like provided in the projector is 50 ℃ or higher. In addition, when the projector is a high-luminance model, the peripheral temperature of the wire grid polarizer or the like may be close to 100 ℃. Therefore, in the case of the film type wire grid polarizing element of the conventional example, the surface temperature of the grid structure may locally exceed 150 ℃, and there is a problem in terms of durability of the wire grid polarizing element.

In contrast, the hybrid-side wire grid polarizer 1 according to embodiments 1 to 10 of the present invention has a structure in which the base portion 21 and the plurality of convex strips 22 of the grid structure 20 are directly formed on the substrate 10 made of an inorganic material. From this, it is clear that examples 1 to 10 can significantly reduce the temperature difference Δt because the thickness TB of the base portion 21 (total thickness D _ALL which is a PMMA material) can be made much thinner than the conventional examples. As a result, in examples 1 to 10, heat of the base portion 21 of the grid structure 20 was able to be radiated to the outside via the substrate 10 made of an inorganic material, and therefore it was confirmed that the heat radiation property and durability of the polarizing element 1 were excellent.

Here, in examples 1 to 10, it is found that by setting the thickness TB of the base portion 21 to 0.15[ mm ] or less, the temperature difference Δt can be suppressed to 32 ℃ or less, and the temperature difference Δt=52.9 ℃ can be reduced by about 40% or more compared to the temperature difference Δt=52.9 ℃ of the conventional example. Thus, it was confirmed that by setting the thickness TB of the base portion 21 to 0.15[ mm ] or less, the heat of the grid structure 20 can be quickly transferred to the substrate 10, and the heat can be efficiently dissipated from the substrate 10 to the outside.

In examples 3 to 10, it was found that by setting the thickness TB of the base portion 21 to 0.09[ mm ] or less, the temperature difference Δt was suppressed to 20 ℃ or less, and the temperature difference Δt was reduced by about 65% or more as compared with the temperature difference Δt=52.9 ℃ in the conventional example. By setting the thickness TB of the base portion 21 to 0.09[ mm ] or less, heat of the grid structure 20 can be quickly transferred to the substrate 10, and heat can be efficiently dissipated from the substrate 10 to the outside. This proves that the reliability of the heat dissipation performance of the wire grid polarizing element 1 can be further improved.

In particular, by setting the thickness TB of the base portion 21 to 0.045[ mm ] or less, the temperature difference Δt can be suppressed to 10 ℃ or less, and the temperature difference Δt can be reduced by about 80% or more as compared with the temperature difference Δt=52.9 ℃ in the conventional example. From this, it is found that the thickness TB of the base portion 21 is more preferably 0.045[ mm ] or less from the viewpoint of improving the reliability of heat dissipation. Further, by setting the thickness TB of the base 21 to 0.02[ mm ] or less, the temperature difference Δt can be suppressed to 5 ℃ or less, and the temperature difference Δt can be reduced by about 90% or more as compared with the temperature difference Δt=52.9 ℃ in the conventional example. From this, it is found that the thickness TB of the base portion 21 is more preferably 0.002[ mm ] or less from the viewpoint of improving the reliability of heat dissipation.

In this way, it was confirmed that the thickness TB of the base portion 21 is preferably 0.09[ mm ] or less, more preferably 0.045[ mm ] or less, and particularly preferably 0.02[ mm ] or less, in order to improve the heat dissipation and durability of the polarizing element 1.

In the above-described embodiment, PMMA is used as the material of the grid structure 20, but the material of the grid structure of the present invention is not limited to the above example, and various organic materials other than PMMA may be used.

<3 > Results of verification of composition of organic Material (photo-curable acrylic resin for imprinting)

Examples 31 to 38 and comparative examples 1 to 9 were prepared as photocurable acrylic resins for imprinting.

The viscosities of the photocurable acrylic resins for imprinting according to examples 31 to 38 and comparative examples 1 to 9 were measured. Viscosity was measured using a conical plate in a Brookfield viscometer, manufactured by the english refiner corporation.

YI values of cured products of the photocurable acrylic resins for imprinting according to examples 31 to 38 and comparative examples 1 to 9 were measured after the cured products were kept at 120℃for 500 hours (heat treatment). YI value was calculated based on the measurement result using an ultraviolet-visible-near-infrared spectrophotometer V-770 manufactured by Nippon Spectropha Co. The measurement conditions for calculating the YI value and the method for calculating the YI value are the same as those in the above embodiment.

The cured products of the photocurable acrylic resins for imprinting according to examples 31 to 38 and comparative examples 1 to 9 were measured for the average transmittance of the cured products with respect to light in the wavelength region of 430nm to 680nm and below and the average transmittance of the cured products with respect to light in the wavelength region of 430nm to 510nm and below before the heat treatment (500 hours at 120 ℃) was performed. Further, after the cured products of the photocurable acrylic resins for imprinting according to examples 3 to 38 and comparative examples 1 to 9 were kept at 120℃for 500 hours, the average transmittance of the cured products with respect to light in the wavelength region of 430nm to 680nm, and the average transmittance of the cured products with respect to light in the wavelength region of 430nm to 510nm were measured. The average transmittance is calculated by measuring the transmittance every 1nm in a wavelength region of 430nm to 680nm, and simply averaging the obtained 251 pieces of measurement data. The average transmittance was measured using an ultraviolet-visible-near-infrared spectrophotometer V-770 manufactured by japan spectroscopy corporation.

The storage modulus at 30 ℃, the storage modulus at 120 ℃, the storage modulus at 130 ℃, and the storage modulus at 140 ℃ of the cured products of the photocurable acrylic resins for imprint according to examples 31 to 38 and comparative examples 1 to 9 were measured. The storage modulus was measured by DMA7100, manufactured by hitachi high technology, inc. Sheets of cured products of the photocurable acrylic resins for imprinting according to examples 31 to 38 and comparative examples 1 to 9 were cut into pieces of 20mm in the longitudinal direction and 3mm in the transverse direction, and in the stretching mode, the temperature was raised at 5℃per minute at a constant frequency (1 Hz) to measure the storage modulus at 25℃to 300 ℃.

The glass transition temperatures Tg of cured products of the photocurable acrylic resins for imprinting according to examples 31 to 38 and comparative examples 1 to 9 were measured. The glass transition temperature Tg was measured by DMA7100, manufactured by Hitachi Ltd. The measurement was carried out by cutting the sheets of cured products of the photocurable acrylic resins for imprint according to examples 31 to 38 and comparative examples 1 to 9 into pieces of 20mm in the longitudinal direction and 3mm in the transverse direction, heating the sheets at a constant frequency (1 Hz) at 5℃per minute in the stretching mode, and confirming the maximum value of the loss tangent tan. Delta. At 25℃to 300 ℃.

The compositions and viscosities of the photocurable acrylic resins for imprinting of examples 31 to 34 are shown in table 5 below. YI values, average transmittance, storage modulus, and glass transition temperature Tg of cured products of the photocurable acrylic resins for imprinting according to examples 31 to 34 are shown in Table 6 below.

The compositions and viscosities of the photocurable acrylic resins for imprinting of examples 35 to 38 are shown in table 7 below. YI values, average transmittance, storage modulus, and glass transition temperature Tg of cured products of the photocurable acrylic resins for imprinting according to examples 35 to 38 are shown in Table 8 below.

The compositions and viscosities of the photocurable acrylic resins for imprinting of comparative examples 1 to 3 are shown in table 9 below. The YI values, average transmittance, storage modulus, and glass transition temperature Tg of cured products of the photocurable acrylic resins for imprinting according to comparative examples 1 to 3 are shown in table 10 below.

The compositions and viscosities of the photocurable acrylic resins for imprinting of comparative examples 4 to 6 are shown in table 11 below. The YI values, average transmittance, storage modulus, and glass transition temperature Tg of cured products of the photocurable acrylic resins for imprinting according to comparative examples 4 to 6 are shown in table 12 below.

The compositions and viscosities of the photocurable acrylic resins for imprinting of comparative examples 7 to 9 are shown in table 13 below. The YI values, average transmittance, storage modulus, and glass transition temperature Tg of cured products of the photocurable acrylic resins for imprinting according to comparative examples 7 to 9 are shown in table 14 below.

The content units in tables 5, 7, 9, 11, and 13 are mass%. The viscosities shown in tables 5, 7, 9, 11 and 13 were the viscosities [ mPas ] at 25 ℃.

TABLE 5

TABLE 6

Example 31

As shown in table 5, in example 31, as the photopolymerization component, only the resin (a), the resin (B), the resin (C), and the resin (D) were contained, and the photopolymerization initiator was also contained. As the resin (A), KAYARAD R-684 (manufactured by Kayarad Co., ltd.) was used. As the resin (B), 1, 6-Hexane Diol Diacrylate (HDDA) was used. As the resin (C), isobornyl acrylate (IBOA) was used. Isobornyl acrylate "IBOA-B" manufactured by Daicel Ornex Co., ltd. As the resin (D), dipentaerythritol hexaacrylate (DPHA) was used. As the photopolymerization initiator, "Irgacure819" manufactured by IGM RESINS B.V. was used. In example 31, the content of the resin (a), the content of the resin (B), and the content of the resin (C) and the resin (D) were 30 mass%, 20 mass%, and 20 mass%, respectively, in the entire photopolymerizable component. That is, in example 31, the total content of the resin (a) and the resin (B) in the entire photopolymerizable component was 50% by mass, and the total content of the resin (B) and the resin (C) was 50%. In example 31, the content of the photopolymerization initiator was 1% by mass when the content of the entire photopolymerization component was 100% by mass.

As shown in table 5, the viscosity of the photocurable acrylic resin for imprinting of example 31 was 34.4mpa·s.

As shown in table 6, the YI value of the cured product of the photocurable acrylic resin for imprint of example 31 was 2.4. From the above results, it was confirmed that even when the cured product of example 31 was subjected to heat treatment, the YI value could be maintained low.

As shown in table 6, the cured product of the photocurable acrylic resin for imprint of example 31 had an average transmittance of 92.2% for light in the wavelength region of 430nm to 680nm before heat treatment and an average transmittance of 91.9% for light in the wavelength region of 430nm to 510nm before heat treatment. In addition, the cured product of the photocurable acrylic resin for imprinting of example 31 had an average transmittance of 91.7% for light in a wavelength region of 430nm to 680nm after heat treatment and an average transmittance of 90.7% for light in a wavelength region of 430nm to 510nm after heat treatment.

In the cured product of example 31, the difference Δa between the average transmittance of light in the wavelength region of 430nm to 680nm (average transmittance before heat treatment and average transmittance after heat treatment) before and after heat treatment was-0.5%. In the cured product of example 31, the difference Δa between the average transmittance of light in the wavelength region of 430nm to 510nm in the range of light before and after the heat treatment was carried out was-1.2%. From the above results, it was confirmed that even when the cured product of example 31 was subjected to heat treatment, the average transmittance of light in the wavelength region of 430nm to 680nm, and the average transmittance of light in the wavelength region of 430nm to 510nm were hardly decreased.

As shown in Table 6, the cured product of the photocurable acrylic resin for imprinting of example 31 had a storage modulus at 30℃of 1.6X10- ⁹ Pa. The cured product of the photocurable acrylic resin for imprinting of example 31 had a storage modulus at 120℃of 6.5X10 ⁸ Pa. The cured product of the photocurable acrylic resin for imprinting of example 31 had a storage modulus of 5.7X10 ⁸ Pa at 130 ℃. The cured product of the photocurable acrylic resin for imprinting of example 31 had a storage modulus at 140℃of 5.0X10 ⁸ Pa.

The rate of change in storage modulus at 120℃relative to storage modulus at 30℃of the cured product of example 31 (storage modulus at 120℃/storage modulus at 30℃. Times.100%) was 41.6%. The rate of change in storage modulus at 130℃relative to storage modulus at 30℃of the cured product of example 31 (storage modulus at 130℃/storage modulus at 30 ℃ X100%) was 36.4%. The rate of change in storage modulus at 140℃relative to storage modulus at 30℃of the cured product of example 31 (storage modulus at 140℃/storage modulus at 30℃. Times.100%) was 31.8%. From the above results, it was confirmed that the cured product of example 31 had a high storage modulus of 1.6X10 ⁹ Pa before the heat treatment was performed. It was also confirmed that the decrease in storage modulus was suppressed even when the cured product of example 31 was subjected to heat treatment.

As shown in table 6, the glass transition temperature Tg of the cured product of the photocurable acrylic resin for imprinting of example 31 was 142.6 ℃. From the above results, it was confirmed that the cured product of example 31 had a high glass transition temperature Tg.

Example 32

As shown in table 5, in example 32, as the photopolymerization component, only the resin (a), the resin (B), the resin (C), and the resin (D) were contained, and the photopolymerization initiator was also contained. The resin (a), the resin (B), the resin (C), the resin (D), and the photopolymerization initiator were the same as in example 31. In example 32, the content of the resin (a) in the entire photopolymerizable component was 40 mass%, the content of the resin (B) was 30 mass%, the content of the resin (C) was 29 mass%, and the content of the resin (D) was 1 mass%. That is, in example 32, the total content of the resin (a) and the resin (B) in the entire photopolymerizable component was 70 mass%, and the total content of the resin (B) and the resin (C) was 59%. In example 32, the content of the photopolymerization initiator was 1% by mass when the content of the entire photopolymerization component was 100% by mass. That is, example 32 differs from example 31 only in the content of the resins (a) to (D).

As shown in table 5, the viscosity of the photocurable acrylic resin for imprinting of example 32 was 17.4mpa·s. The photocurable acrylic resin for imprinting of example 32 has a higher total content of the resin (B) and the resin (C) and a lower content of the resin (D) than the photocurable acrylic resin for imprinting of example 31. From this, it can be inferred that the viscosity of the imprint photocurable acrylic resin of example 32 is lower than that of the imprint photocurable acrylic resin of example 31.

As shown in table 6, the YI value of the cured product of the photocurable acrylic resin for imprint of example 32 was 1.9. From the above results, it was confirmed that even when the cured product of example 32 was subjected to heat treatment, the YI value could be maintained low. The photocurable acrylic resin for imprinting of example 32 has a higher total content of the resin (a) and the resin (B) than the photocurable acrylic resin for imprinting of example 31. From this, it can be inferred that the YI value of the cured product of the imprint photocurable acrylic resin of example 32 is lower than that of the cured product of the imprint photocurable acrylic resin of example 31.

As shown in table 6, the average transmittance of light in the wavelength region of 430nm to 680nm in the cured product of the photocurable acrylic resin for imprint of example 32 before the heat treatment was 91.5%, and the average transmittance of light in the wavelength region of 430nm to 510nm before the heat treatment was 91.1%. In addition, in the cured product of the photocurable acrylic resin for imprinting of example 32, the average transmittance of light in the wavelength region of 430nm to 680nm after heat treatment was 91.4%, and the average transmittance of light in the wavelength region of 430nm to 510nm after heat treatment was 90.5%.

In the cured product of example 32, the difference Δa between the average transmittance of light in the wavelength region of 430nm to 680nm (average transmittance before heat treatment and average transmittance after heat treatment) before and after heat treatment was-0.1%. In the cured product of example 32, the difference Δa between the average transmittance of light in the wavelength region of 430nm to 510nm in the range of not less than 0.6% before and after the heat treatment was performed. From the above results, it was confirmed that even when the cured product of example 32 was subjected to heat treatment, the average transmittance of light in the wavelength region of 430nm to 680nm, and the average transmittance of light in the wavelength region of 430nm to 510nm were hardly decreased. The photocurable acrylic resin for imprinting of example 32 has a higher total content of the resin (a) and the resin (B) than the photocurable acrylic resin for imprinting of example 31. From this, it can be inferred that the difference Δa in average transmittance of the cured product of the imprint-photocurable acrylic resin of example 32 is smaller than the difference Δa in average transmittance of the cured product of the imprint-photocurable acrylic resin of example 31.

As shown in Table 6, the cured product of the photocurable acrylic resin for imprint of example 32 had a storage modulus at 30℃of 2.0X10 ⁹ Pa. The cured product of the photocurable acrylic resin for imprinting of example 32 had a storage modulus at 120℃of 6.2X10 ⁸ Pa. The cured product of the photocurable acrylic resin for imprinting of example 32 had a storage modulus of 5.6X10 ⁸ Pa at 130 ℃. The cured product of the photocurable acrylic resin for imprinting of example 32 had a storage modulus at 140℃of 5.0X10 ⁸ Pa.

The rate of change in storage modulus at 120℃relative to storage modulus at 30℃of the cured product of example 32 (storage modulus at 120℃/storage modulus at 30℃. Times.100%) was 30.9%. The rate of change in storage modulus at 130℃relative to storage modulus at 30℃of the cured product of example 32 (storage modulus at 130℃/storage modulus at 30 ℃ X100%) was 27.6%. The rate of change in storage modulus at 140℃relative to storage modulus at 30℃of the cured product of example 32 (storage modulus at 140℃/storage modulus at 30℃. Times.100%) was 25.0%. From the above results, it was confirmed that the cured product of example 32 had a relatively high storage modulus of 2.0X10 ⁹ Pa before the heat treatment was performed. It was also confirmed that the decrease in storage modulus was suppressed even when the cured product of example 32 was subjected to heat treatment.

As shown in table 6, the glass transition temperature Tg of the cured product of the photocurable acrylic resin for imprint of example 32 was 174.2 ℃. From the above results, it was confirmed that the cured product of example 32 had a high glass transition temperature Tg.

Example 33

As shown in table 5, in example 33, as the photopolymerization component, only the resin (a), the resin (B), the resin (C), and the resin (D) were contained, and the photopolymerization initiator was also contained. The resin (a), the resin (B), the resin (C), the resin (D), and the photopolymerization initiator were the same as in example 31. In example 33, the content of the resin (a) in the entire photopolymerizable component was 20 mass%, the content of the resin (B) was 40 mass%, the content of the resin (C) was 30 mass%, and the content of the resin (D) was 10 mass%. That is, in example 33, the total content of the resin (a) and the resin (B) in the entire photopolymerizable component was 60 mass%, and the total content of the resin (B) and the resin (C) was 70%. In example 33, the content of the photopolymerization initiator was 1% by mass when the content of the entire photopolymerization component was 100% by mass. That is, example 33 differs from example 31 only in the content of the resins (a) to (D).

As shown in table 5, the viscosity of the photocurable acrylic resin for imprinting of example 33 was 19.13mpa·s. The photocurable acrylic resin for imprinting of example 33 has a higher total content of the resin (B) and the resin (C) and a lower content of the resin (D) than the photocurable acrylic resin for imprinting of example 31. From this, it can be inferred that the viscosity of the imprint photocurable acrylic resin of example 33 is lower than that of the imprint photocurable acrylic resin of example 31.

As shown in table 6, the YI value of the cured product of the photocurable acrylic resin for imprint of example 33 was 1.5. From the above results, it was confirmed that even when the cured product of example 33 was subjected to heat treatment, the YI value could be maintained low. The photocurable acrylic resin for imprinting of example 33 has a higher total content of the resin (a) and the resin (B) than the photocurable acrylic resin for imprinting of example 31. From this, it can be inferred that the YI value of the cured product of the imprint photocurable acrylic resin of example 33 is lower than that of the cured product of the imprint photocurable acrylic resin of example 31.

As shown in table 6, the average transmittance of light in the wavelength region of 430nm to 680nm in the cured product of the photocurable acrylic resin for imprint of example 33 before the heat treatment was 92.5%, and the average transmittance of light in the wavelength region of 430nm to 510nm before the heat treatment was 91.7%. In addition, the cured product of the photocurable acrylic resin for imprinting of example 33 had an average transmittance of 92.4% for light in the wavelength region of 430nm to 680nm after heat treatment and an average transmittance of 91.8% for light in the wavelength region of 430nm to 510nm after heat treatment.

In the cured product of example 33, the difference Δa between the average transmittance of light in the wavelength region of 430nm to 680nm (average transmittance before heat treatment and average transmittance after heat treatment) before and after heat treatment was-0.1%. In the cured product of example 33, the difference Δa between the average transmittance of light in the wavelength region of 430nm to 510nm in the range of light before and after the heat treatment was carried out was +0.1%. From the above results, it was confirmed that even when the cured product of example 33 was subjected to heat treatment, the average transmittance of light in the wavelength region of 430nm to 680nm, and the average transmittance of light in the wavelength region of 430nm to 510nm were hardly decreased. The photocurable acrylic resin for imprinting of example 33 has a higher total content of the resin (a) and the resin (B) than the photocurable acrylic resin for imprinting of example 31. From this, it can be inferred that the difference Δa in average transmittance of the cured product of the imprint-photocurable acrylic resin of example 33 is smaller than the difference Δa in average transmittance of the cured product of the imprint-photocurable acrylic resin of example 31.

As shown in Table 6, the cured product of the photocurable acrylic resin for imprinting of example 33 had a storage modulus at 30℃of 2.1X10- ⁹ Pa. The cured product of the photocurable acrylic resin for imprinting of example 33 had a storage modulus at 120℃of 7.1X10 ⁸ Pa. The cured product of the photocurable acrylic resin for imprinting of example 33 had a storage modulus of 5.9X10 ⁸ Pa at 130 ℃. The cured product of the photocurable acrylic resin for imprinting of example 33 had a storage modulus at 140℃of 5.0X10 ⁸ Pa.

The rate of change in storage modulus at 120℃relative to storage modulus at 30℃of the cured product of example 33 (storage modulus at 120℃/storage modulus at 30℃. Times.100%) was 33.4%. The rate of change in storage modulus at 130℃relative to storage modulus at 30℃of the cured product of example 33 (storage modulus at 130℃/storage modulus at 30 ℃ X100%) was 27.8%. The rate of change in storage modulus at 140℃relative to storage modulus at 30℃of the cured product of example 33 (storage modulus at 140℃/storage modulus at 30℃. Times.100%) was 23.5%. From the above results, it was confirmed that the cured product of example 33 had a relatively high storage modulus of 2.1X10 ⁹ Pa before the heat treatment was performed. It was also confirmed that the decrease in storage modulus was suppressed even when the cured product of example 33 was subjected to heat treatment.

As shown in table 6, the glass transition temperature Tg of the cured product of the photocurable acrylic resin for imprint of example 33 was 126.1 ℃. From the above results, it was confirmed that the cured product of example 33 had a higher glass transition temperature Tg.

Example 34

As shown in table 5, in example 34, as the photopolymerization component, only the resin (a), the resin (B), and the resin (C) were contained, and the photopolymerization initiator was also contained. The resin (a), the resin (B), the resin (C) and the photopolymerization initiator were the same as in example 31. In example 34, the content of the resin (a) in the entire photopolymerizable component was 40 mass%, the content of the resin (B) was 30 mass%, and the content of the resin (C) was 30 mass%. That is, in example 34, the total content of the resin (a) and the resin (B) in the entire photopolymerizable component was 70 mass%, and the total content of the resin (B) and the resin (C) was 60%. In example 34, the content of the photopolymerization initiator was 1% by mass when the content of the entire photopolymerization component was 100% by mass. That is, example 34 was different from examples 31 to 33, and contained no resin (D).

As shown in table 5, the viscosity of the photocurable acrylic resin for imprinting of example 34 was 15.07mpa·s. The photocurable acrylic resin for imprinting of example 34 contained no resin (D) as compared with the photocurable acrylic resins for imprinting of examples 31 to 33. From this, it can be inferred that the viscosity of the imprint photocurable acrylic resin of example 34 is lower than the viscosities of the imprint photocurable acrylic resins of examples 31 to 33.

As shown in table 6, the YI value of the cured product of the photocurable acrylic resin for imprint of example 34 was 1.3. From the above results, it was confirmed that even when the cured product of example 34 was subjected to heat treatment, the YI value could be maintained low. The photocurable acrylic resin for imprinting of example 34 has a higher total content of the resin (a) and the resin (B) than the photocurable acrylic resin for imprinting of example 31. From this, it can be inferred that the YI value of the cured product of the imprint photocurable acrylic resin of example 34 is lower than that of the cured product of the imprint photocurable acrylic resin of example 31.

As shown in table 6, the average transmittance of light in the wavelength region of 430nm to 680nm in the cured product of the photocurable acrylic resin for imprint of example 34 before the heat treatment was 91.4%, and the average transmittance of light in the wavelength region of 430nm to 510nm before the heat treatment was 90.5%. In addition, in the cured product of the photocurable acrylic resin for imprinting of example 34, the average transmittance of light in the wavelength region of 430nm to 680nm after heat treatment was 91.8%, and the average transmittance of light in the wavelength region of 430nm to 510nm after heat treatment was 91.2%.

In the cured product of example 34, the difference Δa between the average transmittance of light in the wavelength region of 430nm to 680nm (average transmittance before heat treatment and average transmittance after heat treatment) before and after heat treatment was +0.3%. In the cured product of example 34, the difference Δa between the average transmittance of light in the wavelength region of 430nm to 510nm in the range of light before and after the heat treatment was carried out was +0.7%. From the above results, it was confirmed that even when the cured product of example 34 was subjected to heat treatment, the average transmittance of light in the wavelength region of 430nm to 680nm, and the average transmittance of light in the wavelength region of 430nm to 510nm were hardly decreased. The photocurable acrylic resin for imprinting of example 34 has a higher total content of the resin (a) and the resin (B) than the photocurable acrylic resin for imprinting of example 31. From this, it can be inferred that the difference Δa in average transmittance of the cured product of the imprint-photocurable acrylic resin of example 34 is smaller than the difference Δa in average transmittance of the cured product of the imprint-photocurable acrylic resin of example 31.

As shown in Table 6, the cured product of the photocurable acrylic resin for imprint of example 34 had a storage modulus at 30℃of 2.2X10- ⁹ Pa. The cured product of the photocurable acrylic resin for imprinting of example 34 had a storage modulus at 120℃of 3.9X10 ⁸ Pa. The cured product of the photocurable acrylic resin for imprinting of example 34 had a storage modulus at 130℃of 3.1X10- ⁸ Pa. The cured product of the photocurable acrylic resin for imprinting of example 34 had a storage modulus at 140℃of 2.6X10 ⁸ Pa.

The rate of change in storage modulus at 120℃relative to storage modulus at 30℃of the cured product of example 34 (storage modulus at 120℃/storage modulus at 30℃. Times.100%) was 17.8%. The rate of change in storage modulus at 130℃relative to storage modulus at 30℃of the cured product of example 34 (storage modulus at 130℃/storage modulus at 30 ℃ X100%) was 14.0%. The rate of change in storage modulus at 140℃relative to storage modulus at 30℃of the cured product of example 34 (storage modulus at 140℃/storage modulus at 30℃. Times.100%) was 11.9%. From the above results, it was confirmed that the cured product of example 34 had a relatively high storage modulus of 2.2X10 ⁹ Pa before the heat treatment was performed. It was also confirmed that the decrease in storage modulus was suppressed even when the cured product of example 34 was subjected to heat treatment. In addition, the imprint photocurable acrylic resin of example 34 contained no resin (D) as compared with the imprint photocurable acrylic resin of example 32. From this, it can be inferred that the change rate of the storage modulus of the cured product of the imprint photocurable acrylic resin of example 34 is smaller than that of the cured product of the imprint photocurable acrylic resin of example 32.

As shown in table 6, the glass transition temperature Tg of the cured product of the photocurable acrylic resin for imprinting of example 34 was 115.5 ℃. From the above results, it was confirmed that the cured product of example 34 had a higher glass transition temperature Tg. In addition, the imprint photocurable acrylic resin of example 34 contained no resin (D) as compared with the imprint photocurable acrylic resin of example 32. From this, it can be inferred that the glass transition temperature Tg of the cured product of the imprint photocurable acrylic resin of example 34 is lower than the glass transition temperature Tg of the cured product of the imprint photocurable acrylic resin of example 32.

TABLE 7

TABLE 8

Example 35

As shown in table 7, in example 35, as the photopolymerization component, only the resin (a), the resin (B), the resin (C), and the resin (D) were contained, and the photopolymerization initiator was also contained. The resin (a), the resin (B), the resin (C), the resin (D), and the photopolymerization initiator were the same as in example 31. In example 35, the content of the resin (a) in the entire photopolymerizable component was 30 mass%, the content of the resin (B) was 30 mass%, the content of the resin (C) was 30 mass%, and the content of the resin (D) was 10 mass%. That is, in example 35, the total content of the resin (a) and the resin (B) in the entire photopolymerizable component was 60 mass%, and the total content of the resin (B) and the resin (C) was 60%. In example 35, the content of the photopolymerization initiator was 1% by mass when the content of the entire photopolymerization component was 100% by mass. That is, example 35 differs from example 31 only in the content of the resin (B) and the resin (D).

As shown in table 7, the viscosity of the photocurable acrylic resin for imprinting of example 35 was 18.97mpa·s. The photocurable acrylic resin for imprinting of example 35 has a higher total content of the resin (B) and the resin (C) and a lower content of the resin (D) than the photocurable acrylic resin for imprinting of example 31. From this, it can be inferred that the viscosity of the imprint photocurable acrylic resin of example 35 is lower than that of the imprint photocurable acrylic resin of example 31.

As shown in table 8, the YI value of the cured product of the photocurable acrylic resin for imprint of example 35 was 1.2. From the above results, it was confirmed that even when the cured product of example 35 was subjected to heat treatment, the YI value could be maintained low.

As shown in table 8, the average transmittance of light in the wavelength region of 430nm to 680nm in the cured product of the photocurable acrylic resin for imprint of example 35 before the heat treatment was 91.5%, and the average transmittance of light in the wavelength region of 430nm to 510nm before the heat treatment was 90.6%. In addition, in the cured product of the photocurable acrylic resin for imprinting of example 35, the average transmittance of light in the wavelength region of 430nm to 680nm after heat treatment was 91.7%, and the average transmittance of light in the wavelength region of 430nm to 510nm after heat treatment was 91.2%.

In the cured product of example 35, the difference Δa between the average transmittance of light in the wavelength region of 430nm to 680nm (average transmittance before heat treatment and average transmittance after heat treatment) before and after heat treatment was +0.2%. In the cured product of example 35, the difference Δa between the average transmittance of light in the wavelength region of 430nm to 510nm in the range of not less than +0.6% before and after the heat treatment was performed. From the above results, it was confirmed that even when the cured product of example 35 was subjected to heat treatment, the average transmittance of light in the wavelength region of 430nm to 680nm, and the average transmittance of light in the wavelength region of 430nm to 510nm were hardly decreased.

As shown in table 8, the cured product of the photocurable acrylic resin for imprint of example 35 had a storage modulus at 30 ℃ of 2.0×10 ⁹ Pa. The cured product of the photocurable acrylic resin for imprinting of example 35 had a storage modulus at 120℃of 8.6X10- ⁸ Pa. The cured product of the photocurable acrylic resin for imprinting of example 35 had a storage modulus at 130℃of 7.8X10 ⁸ Pa. The cured product of the photocurable acrylic resin for imprinting of example 35 had a storage modulus at 140℃of 7.2X10 ⁸ Pa.

The rate of change in storage modulus at 120℃relative to storage modulus at 30℃of the cured product of example 35 (storage modulus at 120℃/storage modulus at 30℃. Times.100%) was 43.3%. The rate of change in storage modulus at 130℃relative to storage modulus at 30℃of the cured product of example 35 (storage modulus at 130℃/storage modulus at 30℃. Times.100%) was 39.5%. The rate of change in storage modulus at 140℃relative to storage modulus at 30℃of the cured product of example 35 (storage modulus at 140℃/storage modulus at 30℃. Times.100%) was 36.3%. From the above results, it was confirmed that the cured product of example 35 had a relatively high storage modulus of 2.0X10 ⁹ Pa before the heat treatment was performed. It was also confirmed that the decrease in storage modulus was suppressed even when the cured product of example 35 was subjected to heat treatment.

As shown in table 8, the glass transition temperature Tg of the cured product of the photocurable acrylic resin for imprint of example 35 was 181.3 ℃. From the above results, it was confirmed that the cured product of example 35 had a higher glass transition temperature Tg.

Example 36

As shown in table 7, in example 36, as the photopolymerization component, only the resin (a), the resin (B), the resin (C), and the resin (D) were contained, and the photopolymerization initiator was also contained. The resin (a), the resin (B), the resin (C) and the photopolymerization initiator were the same as in example 35. In example 36, M-9050 manufactured by Toyama Synthesis Co., ltd was used as the resin (D). In example 36, the contents of the resin (a), the resin (B), the resin (C), and the resin (D) in the entire photopolymerizable component were the same as in example 35. In example 36, the content of the photopolymerization initiator was 1% by mass when the content of the entire photopolymerization component was 100% by mass. That is, example 36 was different from example 35 only in resin (D).

As shown in table 7, the viscosity of the photocurable acrylic resin for imprinting of example 36 was 23.02mpa·s. The viscosity of the resin (D) of example 36 was higher than that of the resin (D) of example 35. From this, it can be inferred that the viscosity of the imprint photocurable acrylic resin of example 36 is higher than that of the imprint photocurable acrylic resin of example 35.

As shown in table 8, the YI value of the cured product of the photocurable acrylic resin for imprint of example 36 was 0.8. From the above results, it was confirmed that even when the cured product of example 36 was subjected to heat treatment, the YI value could be maintained low. Further, since the YI values of the cured products of example 35 and 36 were almost not different, it was found that the YI value of the cured product of the imprint photocurable acrylic resin could be kept low even if the resin (D) was a different substance.

As shown in table 8, the cured product of the photocurable acrylic resin for imprint of example 36 had an average transmittance of 92.2% for light in the wavelength region of 430nm to 680nm before heat treatment and an average transmittance of 92.0% for light in the wavelength region of 430nm to 510nm before heat treatment. In addition, in the cured product of the photocurable acrylic resin for imprinting of example 36, the average transmittance of light in the wavelength region of 430nm to 680nm after heat treatment was 92.6%, and the average transmittance of light in the wavelength region of 430nm to 510nm after heat treatment was 92.2%. Since the cured product of example 35 and the cured product of example 36 have little difference in average transmittance, it is found that the cured product of the photocurable acrylic resin for imprint can maintain a high average transmittance even if the resin (D) is a different substance.

In the cured product of example 36, the difference Δa between the average transmittance of light in the wavelength region of 430nm to 680nm (average transmittance before heat treatment and average transmittance after heat treatment) before and after heat treatment was +0.4%. In the cured product of example 36, the difference Δa between the average transmittance of light in the wavelength region of 430nm to 510nm in the range of not less than +0.2% before and after the heat treatment was performed. From the above results, it was confirmed that even when the cured product of example 36 was subjected to heat treatment, the average transmittance of light in the wavelength region of 430nm to 680nm, and the average transmittance of light in the wavelength region of 430nm to 510nm were hardly decreased. Further, since there was little difference in the average transmittance Δa between the cured product of example 35 and the cured product of example 36, it was found that even if the resin (D) was a different substance, the average transmittance hardly decreased even if the cured product of the photocurable acrylic resin for imprint was subjected to the heat treatment.

As shown in Table 8, the cured product of the photocurable acrylic resin for imprint of example 36 had a storage modulus at 30℃of 2.2X10- ⁹ Pa. The cured product of the photocurable acrylic resin for imprinting of example 36 had a storage modulus at 120℃of 8.1X10- ⁸ Pa. The cured product of the photocurable acrylic resin for imprinting of example 36 had a storage modulus at 130℃of 7.3X10 ⁸ Pa. The cured product of the photocurable acrylic resin for imprinting of example 36 had a storage modulus at 140℃of 6.7X10 ⁸ Pa. Since the cured product of example 35 and the cured product of example 36 have little difference in storage modulus, it is clear that the cured product of the photocurable acrylic resin for imprint has a high storage modulus even if the resin (D) is a different substance.

The rate of change in storage modulus at 120℃relative to storage modulus at 30℃of the cured product of example 36 (storage modulus at 120℃/storage modulus at 30℃. Times.100%) was 37.1%. The rate of change in storage modulus at 130℃relative to storage modulus at 30℃of the cured product of example 36 (storage modulus at 130℃/storage modulus at 30℃. Times.100%) was 33.6%. The rate of change in storage modulus at 140℃relative to storage modulus at 30℃of the cured product of example 36 (storage modulus at 140℃/storage modulus at 30℃. Times.100%) was 30.8%. From the above results, it was confirmed that the cured product of example 36 had a relatively high storage modulus of 2.2X10 ⁹ Pa before the heat treatment was performed. It was also confirmed that the decrease in storage modulus was suppressed even when the cured product of example 36 was subjected to heat treatment. Since the cured products of example 35 and 36 have little difference in the change rate of the storage modulus, it is found that the decrease in the storage modulus can be suppressed even when the cured product of the photocurable acrylic resin for imprint is subjected to the heat treatment even if the resin (D) is different.

As shown in table 8, the glass transition temperature Tg of the cured product of the photocurable acrylic resin for imprint of example 36 was 179 ℃. From the above results, it was confirmed that the cured product of example 36 had a higher glass transition temperature Tg. Further, since the cured product of example 35 and the cured product of example 36 have little difference in glass transition temperature Tg, it is found that the cured product of the photocurable acrylic resin for imprint has a high glass transition temperature Tg even if the resin (D) is a different substance.

Example 37

As shown in table 7, in example 37, as the photopolymerization component, only the resin (a), the resin (B), the resin (C), and the resin (D) were contained, and the photopolymerization initiator was also contained. The resin (a), the resin (B), the resin (C) and the photopolymerization initiator were the same as in example 35. In example 37, as the resin (D), trimethylolpropane triacrylate (TMPTA) was used. In example 37, the contents of the resin (a), the resin (B), the resin (C), and the resin (D) in the entire photopolymerizable component were the same as in example 35. In example 37, the content of the photopolymerization initiator was 1% by mass when the content of the entire photopolymerization component was 100% by mass. That is, example 37 differs from example 35 only in resin (D).

As shown in table 7, the viscosity of the photocurable acrylic resin for imprinting of example 37 was 15.43mpa·s. The viscosity of the resin (D) of example 37 was lower than that of the resin (D) of example 35. From this, it can be inferred that the viscosity of the imprint photocurable acrylic resin of example 37 is lower than that of the imprint photocurable acrylic resin of example 35.

As shown in table 8, the YI value of the cured product of the photocurable acrylic resin for imprint of example 37 was 0.9. From the above results, it was confirmed that even when the cured product of example 37 was subjected to heat treatment, the YI value could be maintained low. Further, since the YI values of the cured product of example 35 and the cured product of example 37 were hardly different, it was found that even if the resin (D) was different, the YI value of the cured product of the imprint photocurable acrylic resin could be maintained low.

As shown in table 8, the cured product of the photocurable acrylic resin for imprint of example 37 had an average transmittance of 92.2% for light in the wavelength region of 430nm to 680nm before heat treatment and an average transmittance of 92.0% for light in the wavelength region of 430nm to 510nm before heat treatment. In addition, in the cured product of the photocurable acrylic resin for imprinting of example 37, the average transmittance of light in the wavelength region of 430nm to 680nm after heat treatment was 92.6%, and the average transmittance of light in the wavelength region of 430nm to 510nm after heat treatment was 92.2%. Since the cured product of example 35 and the cured product of example 37 have little difference in average transmittance, it is found that the cured product of the photocurable acrylic resin for imprint can maintain a high average transmittance even if the resin (D) is a different substance.

In the cured product of example 37, the difference Δa between the average transmittance of light in the wavelength region of 430nm to 680nm (average transmittance before heat treatment and average transmittance after heat treatment) before and after heat treatment was +0.3%. In the cured product of example 37, the difference Δa between the average transmittance of light in the wavelength region of 430nm to 510nm in the range of light before and after the heat treatment was carried out was +0.1%. From the above results, it was confirmed that even when the cured product of example 37 was subjected to heat treatment, the average transmittance of light in the wavelength region of 430nm to 680nm, and the average transmittance of light in the wavelength region of 430nm to 510nm were hardly decreased. Further, since there was little difference in the average transmittance Δa between the cured product of example 35 and the cured product of example 37, it was found that even if the resin (D) was a different substance, the average transmittance hardly decreased even if the cured product of the photocurable acrylic resin for imprint was subjected to the heat treatment.

As shown in Table 8, the cured product of the photocurable acrylic resin for imprint of example 37 had a storage modulus at 30℃of 2.1X10- ⁹ Pa. The cured product of the photocurable acrylic resin for imprinting of example 37 had a storage modulus at 120℃of 7.8X10 ⁸ Pa. The cured product of the photocurable acrylic resin for imprinting of example 37 had a storage modulus at 130℃of 7.1X10 ⁸ Pa. The cured product of the photocurable acrylic resin for imprinting of example 37 had a storage modulus at 140℃of 6.3X10 ⁸ Pa. Since the cured product of example 35 and the cured product of example 37 have little difference in storage modulus, it is found that the cured product of the photocurable acrylic resin for imprint has a high storage modulus even if the resin (D) is a different substance.

The rate of change in storage modulus at 120℃relative to storage modulus at 30℃of the cured product of example 37 (storage modulus at 120℃/storage modulus at 30℃. Times.100%) was 37.9%. The rate of change in storage modulus at 130℃relative to storage modulus at 30℃of the cured product of example 37 (storage modulus at 130℃/storage modulus at 30 ℃ X100%) was 34.2%. The rate of change in storage modulus at 140℃relative to storage modulus at 30℃of the cured product of example 37 (storage modulus at 140℃/storage modulus at 30℃. Times.100%) was 30.4%. From the above results, it was confirmed that the cured product of example 37 had a relatively high storage modulus of 2.1X10 ⁹ Pa before the heat treatment was performed. It was also confirmed that the decrease in storage modulus was suppressed even when the cured product of example 37 was subjected to heat treatment. Since the cured products of example 35 and 37 have little difference in the change rate of the storage modulus, it is found that the decrease in the storage modulus can be suppressed even when the cured product of the photocurable acrylic resin for imprint is subjected to the heat treatment even if the resin (D) is different.

As shown in table 8, the glass transition temperature Tg of the cured product of the photocurable acrylic resin for imprinting of example 37 was 170 ℃. From the above results, it was confirmed that the cured product of example 37 had a higher glass transition temperature Tg. Further, since the cured product of example 35 and the cured product of example 37 have little difference in glass transition temperature Tg, it is found that the cured product of the imprint photocurable acrylic resin has a high glass transition temperature Tg even if the resin (D) is a different substance.

Example 38

As shown in table 7, in example 38, as the photopolymerization component, only the resin (a), the resin (B), the resin (C), and the resin (D) were contained, and the photopolymerization initiator was also contained. The resin (a), the resin (C), the resin (D) and the photopolymerization initiator were the same as in example 35. In example 38, as the resin (B), 1, 9-nonanediol diacrylate (NDDA) was used. In example 38, the contents of the resin (a), the resin (B), the resin (C), and the resin (D) in the entire photopolymerizable component were the same as in example 35. In example 38, the content of the photopolymerization initiator was 1% by mass when the content of the entire photopolymerization component was 100% by mass. That is, example 38 differs from example 35 only in resin (B).

As shown in Table 7, the viscosity of the photocurable acrylic resin for imprinting of example 38 was 20.01 mPas. The viscosity of the resin (B) of example 38 is higher than that of the resin (B) of example 35. From this, it can be inferred that the viscosity of the imprint photocurable acrylic resin of example 38 is higher than that of the imprint photocurable acrylic resin of example 35.

As shown in table 8, the YI value of the cured product of the photocurable acrylic resin for imprint of example 38 was 1.0. From the above results, it was confirmed that even when the cured product of example 38 was subjected to heat treatment, a low YI value could be maintained. Further, since the YI values of the cured product of example 35 and the cured product of example 38 were hardly different, it was found that even if the resin (B) was different, the YI value of the cured product of the imprint photocurable acrylic resin could be maintained low.

As shown in table 8, the cured product of the photocurable acrylic resin for imprint of example 38 had an average transmittance of 92.3% for light in the wavelength region of 430nm to 680nm before heat treatment and an average transmittance of 92.0% for light in the wavelength region of 430nm to 510nm before heat treatment. In addition, in the cured product of the photocurable acrylic resin for imprinting of example 38, the average transmittance of light in the wavelength region of 430nm to 680nm after heat treatment was 92.4%, and the average transmittance of light in the wavelength region of 430nm to 510nm after heat treatment was 91.9%. Since the cured product of example 35 and the cured product of example 38 have little difference in average transmittance, it is found that the cured product of the photocurable acrylic resin for imprint can maintain a high average transmittance even if the resin (B) is a different substance.

In the cured product of example 38, the difference Δa between the average transmittance of light in the wavelength region of 430nm to 680nm (average transmittance before heat treatment and average transmittance after heat treatment) before and after heat treatment was +0.2%. In the cured product of example 38, the difference Δa between the average transmittance of light in the wavelength region of 430nm to 510nm in the range of not less than 0.1% before and after the heat treatment was performed. From the above results, it was confirmed that even when the cured product of example 38 was subjected to heat treatment, the average transmittance of light in the wavelength region of 430nm to 680nm, and the average transmittance of light in the wavelength region of 430nm to 510nm were hardly decreased. Further, since there was little difference in the average transmittance Δa between the cured product of example 35 and the cured product of example 38, it was found that even if the resin (B) was a different substance, the average transmittance hardly decreased even if the cured product of the photocurable acrylic resin for imprint was subjected to the heat treatment.

As shown in Table 8, the cured product of the photocurable acrylic resin for imprinting of example 38 had a storage modulus at 30℃of 1.9X10- ⁹ Pa. The cured product of the photocurable acrylic resin for imprinting of example 38 had a storage modulus at 120℃of 7.1X10- ⁸ Pa. The cured product of the photocurable acrylic resin for imprinting of example 38 had a storage modulus at 130℃of 6.4X10 ⁸ Pa. The cured product of the photocurable acrylic resin for imprinting of example 38 had a storage modulus of 5.8X10- ⁸ Pa at 140 ℃. Since the cured product of example 35 and the cured product of example 38 have little difference in storage modulus, it is clear that the cured product of the photocurable acrylic resin for imprint has a high storage modulus even if the resin (B) is a different substance.

The rate of change in storage modulus at 120℃relative to storage modulus at 30℃of the cured product of example 38 (storage modulus at 120℃/storage modulus at 30℃. Times.100%) was 37.4%. The rate of change in storage modulus at 130℃relative to storage modulus at 30℃of the cured product of example 38 (storage modulus at 130℃/storage modulus at 30℃. Times.100%) was 33.5%. The rate of change in storage modulus at 140℃relative to storage modulus at 30℃of the cured product of example 38 (storage modulus at 140℃/storage modulus at 30℃. Times.100%) was 30.3%. From the above results, it was confirmed that the cured product of example 38 had a high storage modulus of 1.9X10 ⁹ Pa before the heat treatment was performed. It was also confirmed that the decrease in storage modulus was suppressed even when the cured product of example 38 was subjected to heat treatment. Since the cured product of example 35 and the cured product of example 38 have little difference in the change rate of the storage modulus, it is found that the decrease in the storage modulus can be suppressed even when the cured product of the photocurable acrylic resin for imprint is subjected to the heat treatment even if the resin (B) is different.

As shown in table 8, the glass transition temperature Tg of the cured product of the photocurable acrylic resin for imprinting of example 38 was 180.6 ℃. From the above results, it was confirmed that the cured product of example 38 had a higher glass transition temperature Tg. Further, since the cured product of example 35 and the cured product of example 38 have little difference in glass transition temperature Tg, it is found that the cured product of the photocurable acrylic resin for imprint has a high glass transition temperature Tg even if the resin (D) is a different substance.

From the above results, it was confirmed that the viscosity of the photocurable acrylic resin for imprinting at 25℃was 35 mPas or less in examples 31 to 38. It was also confirmed that in examples 31 to 38, the YI value of the cured product of the photocurable acrylic resin for imprinting after the cured product was kept at 120 ℃ for 500 hours was 3 or less. It was confirmed that in examples 31 to 38, the cured product of the photocurable acrylic resin for imprinting was kept at 120℃for 500 hours, and the average transmittance of the cured product was 91% or more with respect to light in the wavelength region of 430nm to 680nm, and 90% or more with respect to light in the wavelength region of 430nm to 510 nm. It was also confirmed that in examples 31 to 38, the storage modulus of the cured product of the photocurable acrylic resin for imprint at 30℃was 1.6X10 ⁹ Pa or more and the storage modulus of the cured product at 120℃was 3.9X10 ⁸ Pa or more.

TABLE 9

TABLE 10

Comparative example 1

As shown in table 9, in comparative example 1, as the photopolymerization component, only the resin (C), the resin (D), and the difunctional acrylate monomer were contained, and the photopolymerization initiator was also contained. In comparative example 1, the resin (C) and the photopolymerization initiator were the same as in example 31. In comparative example 1, dipentaerythritol hexaacrylate (DPHA) and "M-9050" manufactured by Toyama Synthesis Co., ltd were used as the resin (D). As the difunctional acrylate monomer, "KAYARAD R-604" manufactured by Nippon Kagaku Co., ltd. "KAYARAD R-604" has a viscosity of 200 mPas to 400 mPas at 25 ℃. In comparative example 1, the content of "KAYARAD R-604" in the entire photopolymerizable component was 20 mass%, the content of the resin (C) was 20 mass%, and the content of the resin (D) was 60 mass%. In comparative example 1, the content of dipentaerythritol hexaacrylate as the resin (D) was 20 mass%, and the content of M-9050 as the resin (D) was 40 mass%. That is, in comparative example 1, the total content of the acrylate monomers of 10 mPas or less at 25℃in the entire photopolymerizable component was 20% by mass. In comparative example 1, the total content of the resins (D) in the entire photopolymerizable component was 60 mass%. In comparative example 1, the content of the photopolymerization initiator was 1% by mass when the content of the entire photopolymerization component was 100% by mass.

As shown in table 9, the viscosity of the photocurable acrylic resin for imprinting of comparative example 1 was 717.5mpa·s. From the above results, it was confirmed that the photocurable acrylic resin for imprinting of comparative example 1 had a total content of 10mpa·s or less at 25 ℃ of less than 50 mass% and the content of the resin (D) exceeded 20 mass%, resulting in an increase in viscosity.

As shown in table 10, the YI value of the cured product of the photocurable acrylic resin for imprinting of comparative example 1 was 6.6. From the above results, it was confirmed that the YI value was increased when the cured product of comparative example 1 was subjected to heat treatment. Therefore, it was found that increasing the content of the resin (D) alone leads to an increase in YI value of the cured product after heat treatment.

As shown in table 10, the average transmittance of light in the wavelength region of 430nm to 680nm in the cured product of the photocurable acrylic resin for imprinting of comparative example 1 before the heat treatment was 91.5%, and the average transmittance of light in the wavelength region of 430nm to 510nm before the heat treatment was 90.6%. In addition, the cured product of the photocurable acrylic resin for imprinting of comparative example 1 had an average transmittance of 90.4% for light in a wavelength region of 430nm to 680nm after heat treatment and an average transmittance of 87.7% for light in a wavelength region of 430nm to 510nm after heat treatment.

In the cured product of comparative example 1, the difference Δa between the average transmittance of light in the wavelength region of 430nm to 680nm (average transmittance before heat treatment and average transmittance after heat treatment) before and after heat treatment was set to-1.1%. In the cured product of comparative example 1, the difference Δa between the average transmittance of light in the wavelength region of 430nm to 510nm in the range of light before and after the heat treatment was carried out was-2.9%. From the above results, it was confirmed that when the cured product of comparative example 1 was subjected to heat treatment, the average transmittance of light in the wavelength region of 430nm to 680nm inclusive and the average transmittance of light in the wavelength region of 430nm to 510nm inclusive were significantly reduced.

As shown in table 10, the cured product of the photocurable acrylic resin for imprinting of comparative example 1 had a storage modulus at 30 ℃ of 2.2x10 ⁹ Pa. The cured product of the photocurable acrylic resin for imprinting of comparative example 1 had a storage modulus at 120℃of 1.3X10- ⁹ Pa. The cured product of the photocurable acrylic resin for imprinting of comparative example 1 had a storage modulus at 130℃of 1.3X10- ⁹ Pa. The cured product of the photocurable acrylic resin for imprinting of comparative example 1 had a storage modulus at 140℃of 1.2X10 ⁹ Pa.

The rate of change in storage modulus at 120℃relative to storage modulus at 30℃of the cured product of comparative example 1 (storage modulus at 120℃/storage modulus at 30℃. Times.100%) was 58.7%. The change rate of the storage modulus at 130℃relative to the storage modulus at 30℃of the cured product of comparative example 1 (storage modulus at 130℃/storage modulus at 30℃. Times.100%) was 56.6%. The change rate of storage modulus at 140℃relative to storage modulus at 30℃of the cured product of comparative example 1 (storage modulus at 140℃/storage modulus at 30℃. Times.100%) was 54.6%.

As shown in table 10, the glass transition temperature Tg of the cured product of the photocurable acrylic resin for imprinting of comparative example 1 was 115 ℃.

Comparative example 2

As shown in Table 9, in comparative example 2, as the photopolymerization component, only "KAYARAD R-604", the resin (B), the resin (C), and the resin (D) were contained, and the photopolymerization initiator was also contained. In comparative example 2, the resin (B), the resin (C), the resin (D), and the photopolymerization initiator were the same as in example 3. In comparative example 2, the content of "KAYARAD R-604" in the entire photopolymerizable component was 40 mass%, the content of the resin (B) was 10 mass%, the content of the resin (C) was 30 mass%, and the content of the resin (D) was 20 mass%. That is, in comparative example 2, the total content of the acrylate monomers (resin (B) +resin (C)) of 10 mPas or less at 25℃in the entire photopolymerizable component was 40% by mass. In comparative example 2, the content of the total of the difunctional acrylate monomers ("KAYARAD R-604" + resin (B)) was 50 mass%. In comparative example 2, the content of the photopolymerization initiator was 1% by mass when the content of the entire photopolymerization component was 100% by mass.

As shown in table 9, the viscosity of the photocurable acrylic resin for imprinting of comparative example 2 was 26.25mpa·s.

As shown in table 10, the YI value of the cured product of the photocurable acrylic resin for imprinting of comparative example 2 was 4.6. From the above results, it was confirmed that the YI value was increased when the cured product of comparative example 2 was subjected to heat treatment. Therefore, it was found that when the resin (A) was not contained, the YI value of the cured product after heat treatment was increased.

As shown in table 10, the average transmittance of light in the wavelength region of 430nm to 680nm in the cured product of the photocurable acrylic resin for imprinting of comparative example 2 before the heat treatment was 92.4%, and the average transmittance of light in the wavelength region of 430nm to 510nm before the heat treatment was 92.2%. In addition, the cured product of the photocurable acrylic resin for imprinting of comparative example 2 had an average transmittance of 91.5% for light in a wavelength region of 430nm to 680nm after heat treatment and an average transmittance of 89.6% for light in a wavelength region of 430nm to 510nm after heat treatment.

In the cured product of comparative example 2, the difference Δa between the average transmittance of light in the wavelength region of 430nm to 680nm (average transmittance before heat treatment and average transmittance after heat treatment) before and after heat treatment was set to-0.9%. In the cured product of comparative example 2, the difference Δa between the average transmittance of light in the wavelength region of 430nm to 510nm in the range of light before and after the heat treatment was carried out was-2.7%. From the above results, it was confirmed that when the cured product of comparative example 2 was subjected to heat treatment, the average transmittance of light in the wavelength region of 430nm to 680nm, and the average transmittance of light in the wavelength region of 430nm to 510nm were significantly reduced.

As shown in table 10, the cured product of the photocurable acrylic resin for imprinting of comparative example 2 had a storage modulus of 2.5×10 ⁹ Pa at 30 ℃. The cured product of the photocurable acrylic resin for imprinting of comparative example 2 had a storage modulus of 9.1X10 ⁸ Pa at 120 ℃. The cured product of the photocurable acrylic resin for imprinting of comparative example 2 had a storage modulus of 8.1X10- ⁸ Pa at 130 ℃. The cured product of the photocurable acrylic resin for imprinting of comparative example 2 had a storage modulus at 140℃of 7.1X10 ⁸ Pa.

The change rate of storage modulus at 120℃relative to storage modulus at 30℃of the cured product of comparative example 2 (storage modulus at 120℃/storage modulus at 30℃. Times.100%) was 36.5%. The rate of change in storage modulus at 130℃relative to storage modulus at 30℃of the cured product of comparative example 2 (storage modulus at 130℃/storage modulus at 30℃. Times.100%) was 32.2%. The change rate of storage modulus at 140℃relative to storage modulus at 30℃of the cured product of comparative example 2 (storage modulus at 140℃/storage modulus at 30℃. Times.100%) was 28.5%.

As shown in table 10, the glass transition temperature Tg of the cured product of the photocurable acrylic resin for imprinting of comparative example 2 was 168.3 ℃.

Comparative example 3

As shown in Table 9, in comparative example 3, as the photopolymerization component, only "KAYARAD R-604", the resin (B), the resin (C), and the resin (D) were contained, and the photopolymerization initiator was also contained. In comparative example 3, the photopolymerization component and the photopolymerization initiator were the same as comparative example 2. In comparative example 3, the content of "KAYARAD R-604" in the entire photopolymerizable component was 40 mass%, the content of the resin (B) was 10 mass%, the content of the resin (C) was 40 mass%, and the content of the resin (D) was 10 mass%. That is, in comparative example 3, the content of only the resin (C) and the resin (D) is different from that in comparative example 2. In comparative example 3, the total content of the acrylate monomers (resin (B) +resin (C)) in the entire photopolymerizable component at 25℃of 10 mPas or less was 50% by mass. In comparative example 3, the total content of the difunctional acrylate monomers (KAYARAD R-604+ resin (B)) was 50 mass%. In comparative example 3, the content of the photopolymerization initiator was 1% by mass when the content of the entire photopolymerization component was 100% by mass.

As shown in table 9, the viscosity of the photocurable acrylic resin for imprinting of comparative example 3 was 39.6mpa·s.

As shown in table 10, the YI value of the cured product of the photocurable acrylic resin for imprinting of comparative example 3 was 3.9. From the above results, it was confirmed that the YI value was increased when the cured product of comparative example 3 was subjected to heat treatment. Therefore, it was found that when the resin (A) was not contained, the YI value of the cured product after heat treatment was increased.

As shown in table 10, the average transmittance of light in the wavelength region of 430nm to 680nm in the cured product of the photocurable acrylic resin for imprinting of comparative example 3 before the heat treatment was 92.7%, and the average transmittance of light in the wavelength region of 430nm to 510nm before the heat treatment was 92.5%. In addition, the cured product of the photocurable acrylic resin for imprinting of comparative example 3 had an average transmittance of 91.9% for light in a wavelength region of 430nm to 680nm after heat treatment and an average transmittance of 90.3% for light in a wavelength region of 430nm to 510nm after heat treatment.

In the cured product of comparative example 3, the difference Δa between the average transmittance of light in the wavelength region of 430nm to 680nm (average transmittance before heat treatment and average transmittance after heat treatment) before and after heat treatment was set to-0.8%. In the cured product of comparative example 3, the difference Δa between the average transmittance of light in the wavelength region of 430nm to 510nm in the range of light before and after the heat treatment was carried out was-2.3%. From the above results, it was confirmed that when the cured product of comparative example 3 was subjected to heat treatment, the average transmittance of light in the wavelength region of 430nm to 680nm, and the average transmittance of light in the wavelength region of 430nm to 510nm were significantly reduced.

As shown in table 10, the cured product of the photocurable acrylic resin for imprinting of comparative example 3 had a storage modulus of 2.0×10 ⁹ Pa at 30 ℃. The cured product of the photocurable acrylic resin for imprinting of comparative example 3 had a storage modulus of 3.3X10 ⁸ Pa at 120 ℃. The cured product of the photocurable acrylic resin for imprinting of comparative example 3 had a storage modulus of 2.6X10- ⁸ Pa at 130 ℃. The cured product of the photocurable acrylic resin for imprinting of comparative example 3 had a storage modulus at 140℃of 2.1X10 ⁸ Pa.

The change rate of storage modulus at 120℃relative to storage modulus at 30℃of the cured product of comparative example 3 (storage modulus at 120℃/storage modulus at 30℃. Times.100%) was 16.7%. The rate of change in storage modulus at 130℃relative to storage modulus at 30℃of the cured product of comparative example 3 (storage modulus at 130℃/storage modulus at 30℃. Times.100%) was 13.3%. The change rate of storage modulus at 140℃relative to storage modulus at 30℃of the cured product of comparative example 3 (storage modulus at 140℃/storage modulus at 30℃. Times.100%) was 11.0%.

As shown in table 10, the glass transition temperature Tg of the cured product of the photocurable acrylic resin for imprinting of comparative example 3 was 113.6 ℃.

TABLE 11

TABLE 12

Comparative example 4

As shown in table 11, in comparative example 4, as the photopolymerization component, only the resin (a), the resin (B), the resin (C), and the resin (D) were contained, and the photopolymerization initiator was also contained. In comparative example 4, the photopolymerization component and the photopolymerization initiator were the same as in example 31. In comparative example 4, the content of the resin (a) in the entire photopolymerizable component was 40 mass%, the content of the resin (B) was 40 mass%, the content of the resin (C) was 10 mass%, and the content of the resin (D) was 10 mass%. In comparative example 4, the total content of the acrylate monomers (resin (B) +resin (C)) in the entire photopolymerizable component at 25℃of 10 mPas or less was 50% by mass. In comparative example 4, the content of the total of the difunctional acrylate monomers (resin (a) +resin (B)) was 80 mass%. In comparative example 4, the content of the photopolymerization initiator was 1% by mass when the content of the entire photopolymerization component was 100% by mass.

As shown in table 11, the viscosity of the photocurable acrylic resin for imprinting of comparative example 4 was 35mpa·s.

As shown in table 12, the YI value of the cured product of the photocurable acrylic resin for imprinting of comparative example 4 was 3.6. From the above results, it was confirmed that the YI value was increased when the cured product of comparative example 4 was subjected to heat treatment. Therefore, it was found that even if the content of the resin (a) is 20 mass% or more and 40 mass% or less relative to the entire photopolymerizable component, when the total content of the resin (a) and the resin (B) exceeds 70 mass% relative to the entire photopolymerizable component, the YI value of the cured product after heat treatment increases.

As shown in table 12, the average transmittance of light in the wavelength region of 430nm to 680nm in the cured product of the photocurable acrylic resin for imprinting of comparative example 4 before the heat treatment was 91.5%, and the average transmittance of light in the wavelength region of 430nm to 510nm before the heat treatment was 90.4%. In addition, the cured product of the photocurable acrylic resin for imprinting of comparative example 4 had an average transmittance of 91.2% for light in a wavelength region of 430nm to 680nm after heat treatment and an average transmittance of 89.7% for light in a wavelength region of 430nm to 510nm after heat treatment. From the above results, it was found that even when the content of the resin (a) is 20 mass% or more and 40 mass% or less relative to the entire photopolymerizable component, when the total content of the resin (a) and the resin (B) exceeds 70 mass% relative to the entire photopolymerizable component, the average transmittance of light in a wavelength region of 430nm to 510nm after the heat treatment of the cured product is reduced.

In the cured product of comparative example 4, the difference Δa between the average transmittance of light in the wavelength region of 430nm to 680nm (average transmittance before heat treatment and average transmittance after heat treatment) before and after heat treatment was set to-0.3%. In the cured product of comparative example 4, the difference Δa between the average transmittance of light in the wavelength region of 430nm to 510nm in the range of light before and after the heat treatment was carried out was-0.6%.

As shown in table 12, the cured product of the photocurable acrylic resin for imprinting of comparative example 4 had a storage modulus of 2.3×10 ⁹ Pa at 30 ℃. The cured product of the photocurable acrylic resin for imprinting of comparative example 4 had a storage modulus at 120℃of 1.0X10 ⁹ Pa. The cured product of the photocurable acrylic resin for imprinting of comparative example 4 had a storage modulus of 9.1X10 ⁸ Pa at 130 ℃. The cured product of the photocurable acrylic resin for imprinting of comparative example 4 had a storage modulus of 8.3X10 ⁸ Pa at 140 ℃.

The rate of change in storage modulus at 120℃relative to storage modulus at 30℃of the cured product of comparative example 4 (storage modulus at 120℃/storage modulus at 30℃. Times.100%) was 44.2%. The rate of change in storage modulus at 130℃relative to storage modulus at 30℃of the cured product of comparative example 4 (storage modulus at 130℃/storage modulus at 30℃. Times.100%) was 39.5%. The change rate of storage modulus at 140℃relative to storage modulus at 30℃of the cured product of comparative example 4 (storage modulus at 140℃/storage modulus at 30℃. Times.100%) was 36.3%.

As shown in table 12, the glass transition temperature Tg of the cured product of the photocurable acrylic resin for imprinting of comparative example 4 was 128 ℃.

Comparative example 5

As shown in Table 11, in comparative example 5, as the photopolymerization component, only "KAYARAD R-604", the resin (C), and the resin (D) were contained, and the photopolymerization initiator was also contained. The resin (C), the resin (D), and the photopolymerization initiator were the same as in example 36. In comparative example 5, the content of "KAYARAD R-604" in the entire photopolymerizable component was 50% by mass, the content of the resin (C) was 30% by mass, and the content of the resin (D) was 20% by mass. That is, in comparative example 5, the total content of the acrylate monomers (resin (C)) of 10 mPas or less at 25℃in the entire photopolymerizable component was 30% by mass. In comparative example 5, the content of the total of the difunctional acrylate monomers ("KAYARAD R-604") was 50 mass%. In comparative example 5, the content of the photopolymerization initiator was 1% by mass when the content of the entire photopolymerization component was 100% by mass.

As shown in table 11, the viscosity of the photocurable acrylic resin for imprinting of comparative example 5 was 192.5mpa·s.

As shown in table 12, the YI value of the cured product of the photocurable acrylic resin for imprinting of comparative example 5 was 3.5. From the above results, it was confirmed that the YI value was increased when the cured product of comparative example 5 was subjected to heat treatment. Therefore, when the resin (a) is not contained, the YI value of the cured product after the heat treatment is increased.

As shown in table 12, the average transmittance of light in the wavelength region of 430nm to 680nm in the cured product of the photocurable acrylic resin for imprinting of comparative example 5 before the heat treatment was 92.1%, and the average transmittance of light in the wavelength region of 430nm to 510nm before the heat treatment was 91.8%. In addition, the cured product of the photocurable acrylic resin for imprinting of comparative example 5 had an average transmittance of 91.4% for light in a wavelength region of 430nm to 680nm after heat treatment and an average transmittance of 90.0% for light in a wavelength region of 430nm to 510nm after heat treatment.

In the cured product of comparative example 5, the difference Δa between the average transmittance of light in the wavelength region of 430nm to 680nm (average transmittance before heat treatment and average transmittance after heat treatment) before and after heat treatment was set to-0.7%. In the cured product of comparative example 5, the difference Δa between the average transmittance of light in the wavelength region of 430nm to 510nm in the range of light before and after the heat treatment was carried out was-1.8%. From the above results, it was confirmed that, in the cured product of comparative example 5, when the resin (a) was not contained, the average transmittance of light in the wavelength region of 430nm to 680nm, and the average transmittance of light in the wavelength region of 430nm to 510nm were significantly reduced when the heat treatment was performed.

As shown in table 12, the storage modulus at 30 ℃ of the cured product of the photocurable acrylic resin for imprinting of comparative example 5 was 1.8x10 ⁹ Pa. The cured product of the photocurable acrylic resin for imprinting of comparative example 5 had a storage modulus of 5.2X10- ⁸ Pa at 120 ℃. The cured product of the photocurable acrylic resin for imprinting of comparative example 5 had a storage modulus of 4.5X10 ⁸ Pa at 130 ℃. The cured product of the photocurable acrylic resin for imprinting of comparative example 5 had a storage modulus of 3.9X10 ⁸ Pa at 140 ℃.

The change rate of storage modulus at 120℃relative to storage modulus at 30℃of the cured product of comparative example 5 (storage modulus at 120℃/storage modulus at 30℃. Times.100%) was 28.5%. The rate of change in storage modulus at 130℃relative to storage modulus at 30℃of the cured product of comparative example 5 (storage modulus at 130℃/storage modulus at 30 ℃ X100%) was 24.7%. The rate of change in storage modulus at 140℃relative to storage modulus at 30℃of the cured product of comparative example 5 (storage modulus at 140℃/storage modulus at 30℃. Times.100%) was 21.2%.

As shown in table 12, the glass transition temperature Tg of the cured product of the photocurable acrylic resin for imprinting of comparative example 5 was 169.6 ℃.

Comparative example 6

As shown in Table 11, in comparative example 6, as the photopolymerization component, only "KAYARAD R-604", the resin (C), and the resin (D) were contained, and the photopolymerization initiator was also contained. In comparative example 6, the resin (C), the resin (D), and the photoinitiator were the same as in example 31. In comparative example 6, the content of "KAYARAD R-604" in the entire photopolymerizable component was 70% by mass, the content of the resin (C) was 20% by mass, and the content of the resin (D) was 10% by mass. That is, in comparative example 6, the total content of the acrylate monomers (resin (C)) of 10 mPas or less at 25℃in the entire photopolymerizable component was 20% by mass. In comparative example 6, the content of the total of the difunctional acrylate monomers ("KAYARAD R-604") was 70% by mass. In comparative example 6, the content of the photopolymerization initiator was 1% by mass when the content of the entire photopolymerization component was 100% by mass.

As shown in table 11, the viscosity of the photocurable acrylic resin for imprinting of comparative example 6 was 245mpa·s.

As shown in table 12, the YI value of the cured product of the photocurable acrylic resin for imprinting of comparative example 6 was 3.1. From the above results, it was confirmed that the YI value was increased when the cured product of comparative example 6 was subjected to heat treatment. Therefore, it was found that when the resin (A) was not contained, the YI value of the cured product after heat treatment was increased.

As shown in table 12, the average transmittance of light in the wavelength region of 430nm to 680nm in the cured product of the photocurable acrylic resin for imprinting of comparative example 6 before the heat treatment was 91.8%, and the average transmittance of light in the wavelength region of 430nm to 510nm before the heat treatment was 90.6%. In addition, the cured product of the photocurable acrylic resin for imprinting of comparative example 6 had an average transmittance of 91.6% for light in a wavelength region of 430nm to 680nm after heat treatment and an average transmittance of 90.4% for light in a wavelength region of 430nm to 510nm after heat treatment.

In the cured product of comparative example 6, the difference Δa between the average transmittance of light in the wavelength region of 430nm to 680nm (average transmittance before heat treatment and average transmittance after heat treatment) before and after heat treatment was set to-0.1%. In the cured product of comparative example 6, the difference Δa between the average transmittance of light in the wavelength region of 430nm to 510nm in the range of light before and after the heat treatment was carried out was-0.2%.

As shown in table 12, the cured product of the photocurable acrylic resin for imprinting of comparative example 6 had a storage modulus of 2.4×10 ⁹ Pa at 30 ℃. The cured product of the photocurable acrylic resin for imprinting of comparative example 6 had a storage modulus at 120℃of 7.5X10- ⁸ Pa. The cured product of the photocurable acrylic resin for imprinting of comparative example 6 had a storage modulus of 6.4X10 ⁸ Pa at 130 ℃. The cured product of the photocurable acrylic resin for imprinting of comparative example 6 had a storage modulus of 5.6X10- ⁸ Pa at 140 ℃.

The rate of change in storage modulus at 120℃relative to storage modulus at 30℃of the cured product of comparative example 6 (storage modulus at 120℃/storage modulus at 30℃. Times.100%) was 31.6%. The rate of change in storage modulus at 130℃relative to storage modulus at 30℃of the cured product of comparative example 6 (storage modulus at 130℃/storage modulus at 30℃. Times.100%) was 27.1%. The rate of change in storage modulus at 140℃relative to storage modulus at 30℃of the cured product of comparative example 6 (storage modulus at 140℃/storage modulus at 30℃. Times.100%) was 23.5%.

As shown in table 12, the glass transition temperature Tg of the cured product of the photocurable acrylic resin for imprinting of comparative example 6 was 164.1 ℃.

TABLE 13

TABLE 14

Comparative example 7

As shown in table 13, in comparative example 7, only the resin (a) and the resin (C) were contained as photopolymerization components, and "IrgacureTPO" manufactured by IGM RESINS b.v. was contained as a photopolymerization initiator. In comparative example 7, benzyl acrylate was used as the resin (C). As the benzyl acrylate, "V#160" was used, which is a benzyl acrylate available from Osaka organic chemical industries, ltd. The benzyl acrylate had a viscosity of 2.2 mPas at 25 ℃. In comparative example 7, the content of the resin (a) in the entire photopolymerizable component was 25 mass%, and the content of the resin (C) was 75 mass%. That is, in comparative example 7, the total content of the acrylate monomers (resin (C)) of 10 mPas or less at 25℃in the entire photopolymerizable component was 75% by mass. In comparative example 7, the content of the total (resin (a)) of the difunctional acrylate monomers was 25 mass%. In comparative example 7, the content of the photopolymerization initiator was 3% by mass when the content of the entire photopolymerization component was 100% by mass.

As shown in table 13, the viscosity of the photocurable acrylic resin for imprinting of comparative example 7 was 4.2mpa·s.

As shown in table 14, the YI value of the cured product of the photocurable acrylic resin for imprinting of comparative example 7 was 1.44.

As shown in table 14, the average transmittance of light in the wavelength region of 430nm to 680nm in the cured product of the photocurable acrylic resin for imprinting of comparative example 7 before the heat treatment was 91.4%, and the average transmittance of light in the wavelength region of 430nm to 510nm before the heat treatment was 91.2%. In addition, the cured product of the photocurable acrylic resin for imprinting of comparative example 7 had an average transmittance of 91.1% for light in a wavelength region of 430nm to 680nm after heat treatment and an average transmittance of 90.5% for light in a wavelength region of 430nm to 510nm after heat treatment.

In the cured product of comparative example 7, the difference Δa between the average transmittance of light in the wavelength region of 430nm to 680nm (average transmittance before heat treatment and average transmittance after heat treatment) before and after heat treatment was set to-0.3%. In the cured product of comparative example 7, the difference Δa between the average transmittance of light in the wavelength region of 430nm to 510nm in the range of light before and after the heat treatment was carried out was-0.7%.

As shown in Table 14, the cured product of the photocurable acrylic resin for imprinting of comparative example 7 had a storage modulus of 7.3X10- ⁸ Pa at 30 ℃. The cured product of the photocurable acrylic resin for imprinting of comparative example 7 had a storage modulus at 120℃of 1.2X10- ⁷ Pa. The cured product of the photocurable acrylic resin for imprinting of comparative example 7 had a storage modulus at 130℃of 1.3X10- ⁷ Pa. The cured product of the photocurable acrylic resin for imprinting of comparative example 7 had a storage modulus at 140℃of 1.4X10 ⁷ Pa.

The change rate of storage modulus at 120℃relative to storage modulus at 30℃of the cured product of comparative example 7 (storage modulus at 120℃/storage modulus at 30℃. Times.100%) was 1.7%. The change rate of the storage modulus at 130℃relative to the storage modulus at 30℃of the cured product of comparative example 7 (storage modulus at 130℃/storage modulus at 30℃. Times.100%) was 1.8%. The change rate of storage modulus at 140℃relative to storage modulus at 30℃of the cured product of comparative example 7 (storage modulus at 140℃/storage modulus at 30℃. Times.100%) was 1.9%. From the above results, it was confirmed that the cured product of comparative example 7 had a low storage modulus of 7.3X10 ⁸ Pa before heat treatment was performed. It was also confirmed that the storage modulus significantly decreased when the cured product of comparative example 7 was subjected to heat treatment. Therefore, it was confirmed that the storage modulus was greatly lowered when the resin (B) was not contained.

As shown in table 14, the glass transition temperature Tg of the cured product of the photocurable acrylic resin for imprinting of comparative example 7 was 35.4 ℃. From the above results, it was confirmed that the glass transition temperature Tg of the cured product of comparative example 7 was particularly low because the resin (B) was not contained.

Comparative example 8

As shown in table 13, in comparative example 8, as the photopolymerization component, only the resin (a) and the resin (C) were contained, and the photopolymerization initiator was also contained. In comparative example 8, the resin (a), the resin (C), and the photopolymerization initiator were the same as comparative example 7. That is, comparative example 8 differs from comparative example 7 only in the content of the resin (a) and the resin (C). In comparative example 8, the content of the resin (a) in the entire photopolymerizable component was 40 mass%, and the content of the resin (C) was 60 mass%. That is, in comparative example 8, the total content of the acrylate monomers (resin (C)) of 10 mPas or less at 25℃in the entire photopolymerizable component was 60% by mass. In comparative example 8, the content of the total (resin (a)) of the difunctional acrylate monomers was 40 mass%. In comparative example 8, the content of the photopolymerization initiator was 3 mass% when the content of the entire photopolymerization component was 100 mass%.

As shown in table 13, the viscosity of the photocurable acrylic resin for imprinting of comparative example 8 was 6.6mpa·s.

As shown in table 14, the YI value of the cured product of the photocurable acrylic resin for imprinting of comparative example 8 was 1.42.

As shown in table 14, the average transmittance of light in the wavelength region of 430nm to 680nm in the cured product of the photocurable acrylic resin for imprinting of comparative example 8 before the heat treatment was 91.6%, and the average transmittance of light in the wavelength region of 430nm to 510nm before the heat treatment was 91.3%. In addition, the cured product of the photocurable acrylic resin for imprinting of comparative example 8 had an average transmittance of 91.2% for light in a wavelength region of 430nm to 680nm after heat treatment and an average transmittance of 90.6% for light in a wavelength region of 430nm to 510nm after heat treatment.

In the cured product of comparative example 8, the difference Δa between the average transmittance of light in the wavelength region of 430nm to 680nm (average transmittance before heat treatment and average transmittance after heat treatment) before and after heat treatment was set to-0.4%. In the cured product of comparative example 8, the difference Δa between the average transmittance of light in the wavelength region of 430nm to 510nm in the range of light before and after the heat treatment was carried out was-0.7%.

As shown in Table 14, the storage modulus at 30℃of the cured product of the photocurable acrylic resin for imprint of comparative example 8 was 2.1X10- ⁹ Pa. The cured product of the photocurable acrylic resin for imprinting of comparative example 8 had a storage modulus of 3.0X10- ⁷ Pa at 120 ℃. The cured product of the photocurable acrylic resin for imprinting of comparative example 8 had a storage modulus of 3.1X10- ⁷ Pa at 130 ℃. The cured product of the photocurable acrylic resin for imprinting of comparative example 8 had a storage modulus of 3.2X10- ⁷ Pa at 140 ℃.

The change rate of storage modulus at 120℃relative to storage modulus at 30℃of the cured product of comparative example 8 (storage modulus at 120℃/storage modulus at 30℃. Times.100%) was 1.4%. The rate of change in storage modulus at 130℃relative to storage modulus at 30℃of the cured product of comparative example 8 (storage modulus at 130℃/storage modulus at 30℃. Times.100%) was 1.5%. The change rate of storage modulus at 140℃relative to storage modulus at 30℃of the cured product of comparative example 8 (storage modulus at 140℃/storage modulus at 30℃. Times.100%) was 1.5%. From the above results, it was confirmed that the cured product of comparative example 8 had a relatively high storage modulus of 2.1X10 ⁹ Pa before the heat treatment was performed. However, it was confirmed that the storage modulus significantly decreased when the cured product of comparative example 8 was subjected to heat treatment. Therefore, it was confirmed that the storage modulus was greatly lowered when the resin (B) was not contained.

As shown in table 14, the glass transition temperature Tg of the cured product of the photocurable acrylic resin for imprinting of comparative example 8 was 46 ℃. From the above results, it was confirmed that the glass transition temperature Tg of the cured product of comparative example 8 was particularly low because the resin (B) was not contained.

Comparative example 9

As shown in table 13, in comparative example 9, as a photopolymerization component, only the resin (B), the resin (D), and the monofunctional monomer were contained, and "IrgacureTPO" manufactured by IGM RESINS b.v. was contained as a photopolymerization initiator. In comparative example 9, 1, 9-nonanediol diacrylate (NDDA) was used as the resin (B). Further, as the resin (D), trimethylolpropane triacrylate (TMPTA) was used. As monofunctional monomers N-vinyl-2-pyrrolidone is used. N-vinyl-2-pyrrolidone has a viscosity of 1.7 mPas at 25 ℃. In comparative example 9, the content of the resin (B) in the entire photopolymerizable component was 33 mass%, the content of the resin (D) was 33 mass%, and the content of N-vinyl-2-pyrrolidone was 32 mass%. That is, in comparative example 9, the total content of the acrylate monomers (resin (B) +monofunctional monomer) of 10 mPas or less at 25℃in the entire photopolymerizable component was 65% by mass. In comparative example 9, the content of the total (resin (B)) of the difunctional acrylate monomers was 33 mass%. In comparative example 9, the content of the photopolymerization initiator was 2% by mass when the content of the entire photopolymerization component was 100% by mass.

As shown in table 13, the viscosity of the photocurable acrylic resin for imprinting of comparative example 9 was 7.9mpa·s.

As shown in table 14, the YI value of the cured product of the photocurable acrylic resin for imprinting of comparative example 9 was 5.8. From the above results, it was confirmed that the YI value was increased when the cured product of comparative example 9 was subjected to heat treatment. Therefore, it was found that when the resin (A) was not contained, the YI value of the cured product after heat treatment was increased.

As shown in table 14, the average transmittance of light in the wavelength region of 430nm to 680nm in the cured product of the photocurable acrylic resin for imprinting of comparative example 9 before the heat treatment was 92.0%, and the average transmittance of light in the wavelength region of 430nm to 510nm before the heat treatment was 91.7%. In addition, the cured product of the photocurable acrylic resin for imprinting of comparative example 9 had an average transmittance of 90.5% for light in the wavelength region of 430nm to 680nm after heat treatment and an average transmittance of 87.8% for light in the wavelength region of 430nm to 510nm after heat treatment.

In the cured product of comparative example 9, the difference Δa between the average transmittance of light in the wavelength region of 430nm to 680nm (average transmittance before heat treatment and average transmittance after heat treatment) before and after heat treatment was set to-1.5%. In the cured product of comparative example 9, the difference Δa between the average transmittance of light in the wavelength region of 430nm to 510nm in the range of light before and after the heat treatment was carried out was-3.9%. From the above results, it was confirmed that when the cured product of comparative example 9 was subjected to heat treatment, the average transmittance of light in the wavelength region of 430nm to 680nm, and the average transmittance of light in the wavelength region of 430nm to 510nm were significantly reduced.

As shown in Table 14, the storage modulus at 30℃of the cured product of the photocurable acrylic resin for imprint of comparative example 9 was 2.4X10 ⁹ Pa. The cured product of the photocurable acrylic resin for imprinting of comparative example 9 had a storage modulus at 120℃of 1.5X10- ⁹ Pa. The cured product of the photocurable acrylic resin for imprinting of comparative example 9 had a storage modulus at 130℃of 1.4X10- ⁹ Pa. The cured product of the photocurable acrylic resin for imprinting of comparative example 9 had a storage modulus at 140℃of 1.3X10- ⁹ Pa.

The change rate of storage modulus at 120℃relative to storage modulus at 30℃of the cured product of comparative example 9 (storage modulus at 120℃/storage modulus at 30℃. Times.100%) was 61.0%. The change rate of storage modulus at 130℃relative to storage modulus at 30℃of the cured product of comparative example 9 (storage modulus at 130℃/storage modulus at 30℃. Times.100%) was 57.3%. The change rate of storage modulus at 140℃relative to storage modulus at 30℃of the cured product of comparative example 9 (storage modulus at 140℃/storage modulus at 30℃. Times.100%) was 52.8%.

As shown in table 14, the glass transition temperature Tg of the cured product of the photocurable acrylic resin for imprinting of comparative example 9 was 180.1 ℃.

Evaluation of examples and comparative examples

In table 15 and table 16 below, the evaluation of heat resistance and viscosity of examples 31 to 38 and comparative examples 1 to 9 is shown in two stages. Regarding the evaluation of heat resistance, heat resistance was evaluated in terms of optical characteristics after heat treatment and shape after heat treatment. Regarding the optical characteristics after the heat treatment, the YI value of the cured product of the photocurable acrylic resin for imprinting after the heat treatment at 120 ℃ for 500 hours was 3 or less, and "o" was evaluated, and "x" was evaluated when it exceeded 3. The shape after the heat treatment was nanoimprint molded on a substrate using a master and an imprint photocurable acrylic resin, and a fine uneven structure was formed on the substrate, and after the heat treatment was performed for 500 hours at 120 ℃, the cross-section of the cured product was observed by a Transmission Electron Microscope (TEM). As a result, the evaluation "o" was performed when there was no shape change compared to the case before the heat treatment, and the evaluation "x" was performed when there was a shape change compared to the case before the heat treatment.

Regarding the viscosity, the following property of the uncured photocurable acrylic resin for imprinting to the master disk and the appearance were evaluated. Regarding the followability of the imprinting photocurable acrylic resin to the master, a master having a known fine uneven structure (cross-sectional structure) was prepared, and the master and the imprinting photocurable acrylic resin were used to perform nanoimprint molding on a substrate, and then the fine uneven structure on the substrate was observed in cross section by a transmission electron microscope. As a result, when the micro concave-convex structure formed on the substrate is similar to the micro concave-convex structure of the master, the evaluation with high follow-up property is "o", and when the micro concave-convex structure on the substrate is significantly different from the micro concave-convex structure of the master (the size of the pattern of the micro concave-convex structure on the substrate is extremely small for the micro concave-convex structure of the master, etc.), the evaluation with poor follow-up property is "x". Regarding the appearance, a master and a photocurable acrylic resin for imprinting were used, nanoimprint molding was performed on a substrate, and then the substrate having a fine uneven structure formed thereon was observed in a dark room by fluorescent lamp transmission and fluorescent lamp reflection. As a result, the pattern of the fine uneven structure was not deformed on the substrate, and the resin on the substrate was not peeled off, and the evaluation "o" was performed as the whole of the substrate, and the pattern of the fine uneven structure was partially deformed on the substrate, and the substrate was uneven, such as the resin peeling off the substrate, and the evaluation "x" was performed as the whole of the substrate.

TABLE 15

TABLE 116

As shown in table 15, the cured products of the photocurable acrylic resins for imprinting of examples 31 to 38 were evaluated for "o" in the optical properties after heat treatment and the shape after heat treatment. The photocurable acrylic resins for imprinting of examples 31 to 38 were also evaluated for "o" in terms of the following property to the master and the appearance. From the above evaluation, it was confirmed that the photocurable acrylic resins for imprinting of examples 31 to 38 had both heat resistance and low viscosity.

On the other hand, as shown in table 16, the cured product of the photocurable acrylic resin for imprinting of comparative example 1 was evaluated for "x" in the optical characteristics after the heat treatment. The photocurable acrylic resin for imprinting of comparative example 1 was also evaluated for "x" in terms of the following property to the master and the appearance. From the above evaluation, it was confirmed that comparative example 1 has low heat resistance and high viscosity.

As shown in table 16, the cured products of the photocurable acrylic resins for imprinting of comparative examples 2 to 4 were evaluated for "x" in the optical properties after the heat treatment. From the above evaluation, it was confirmed that comparative examples 2 to 4 were low in viscosity and low in heat resistance.

As shown in table 16, the cured products of the photocurable acrylic resins for imprinting of comparative examples 5 and 6 were evaluated for "x" in the optical properties after the heat treatment. The photocurable acrylic resins for imprinting of comparative examples 5 and 6 were also evaluated for "x" in terms of the following property to the master and appearance. From the above evaluation, it was confirmed that comparative example 1 has low heat resistance and high viscosity.

As shown in table 16, cured products of the photocurable acrylic resins for imprinting of comparative examples 7 and 8 were evaluated for "x" in the shape after heat treatment. From the above evaluation, it was confirmed that comparative examples 7 and 8 were low in viscosity and low in heat resistance.

As shown in table 16, the cured product of the photocurable acrylic resin for imprinting of comparative example 9 was evaluated for "x" in the optical characteristics after the heat treatment. From the above evaluation, it was confirmed that comparative example 9 was low in viscosity and low in heat resistance.

While the preferred embodiments of the present invention have been described in detail with reference to the drawings, the present invention is not limited to the examples. It is obvious that various changes and modifications will occur to those skilled in the art within the scope of the technical idea described in the claims, and it is needless to say that these are also understood to fall within the technical scope of the present invention.

Industrial applicability

According to the present embodiment, it is possible to provide a polarizing element having excellent polarization characteristics, which does not deteriorate heat radiation and cost at the time of manufacturing, and which is excellent in light transmittance to light having a wide range of incident angles, and a method for manufacturing the polarizing element. Further, according to the present embodiment, a projection display device excellent in polarization characteristics and heat resistance and a vehicle provided with the projection display device can be provided. Further, according to the present embodiment, it is possible to provide an imprint photocurable acrylic resin which reduces the viscosity of an uncured resin composition and is excellent in heat resistance of the cured resin composition.

Description of the reference numerals

1 Wire grid polarizer

2 Light source

3 Display element

4 Reflector

5 Display surface

6 Cover part

10 Substrate

20 Grid structure

21 Base portion

22 Raised strips

23 Grid structure material

24 Concave part

30 Reflective film

40 Protective film

50 Heat dissipation part

60 Master disk

61 Base material for master

62 Metal film for master disk

63 Convex part

64 Release film coating layer

65 Groove

70 Resist mask

80 Metal film

100 Head-up display device

200 Projection display device

210 Light source

220PS converter

230 Polarization beam splitter

240 Reflection type liquid crystal display element

250 Lens

260 Light absorber

Thickness of TS substrate

Thickness of TB base portion

Pitch of P ridge

Height of H-ridge

Height range of side surface of Hx reflecting film coated convex strip

Side thickness of Ds reflective film

Thickness of front end of Dt reflective film

Maximum width of reflective film of W _MAX wrapping raised line (grid maximum width)

Width of bottom of W _B raised strips (grid bottom width)

Width of top of W _T raised line (raised line top width)

W _A effective grid width

W _G gap width.

Claims

1. A wire grid polarizer is characterized by comprising:

a substrate made of an inorganic material;

a grid structure body which is made of an organic material, and in which a base portion provided on the substrate is integrally formed with a plurality of ridge portions protruding from the base portion; and

A functional film which is made of a metal material and which covers a part of the ridge portion,

The photopolymerizable component comprises:

A resin (A); and

A resin (B),

2. A wire grid polarizing element as defined in claim 1, wherein,

The viscosity of the photocurable acrylic resin for imprinting at 25 ℃ is 35 mPas or less.

3. A wire grid polarizing element as defined in claim 1, wherein,

The photopolymerizable component further comprises a resin (C),

4. A wire grid polarizing element as defined in claim 3, wherein,

The resin (C) is a monofunctional acrylate monomer.

5. A wire grid polarizing element as defined in claim 4, wherein,

The resin (C) is isobornyl acrylate.

6. A wire grid polarizing element as defined in claim 1, wherein,

The photopolymerizable component further comprises a resin (D),

The resin (D) is a trifunctional or higher acrylate monomer,

7. A wire grid polarizing element as defined in claim 6, wherein,

The resin (D) is one or more selected from the group consisting of trimethylolpropane triacrylate, dipentaerythritol hexaacrylate, and multifunctional polyester acrylate.

8. A wire grid polarizing element as defined in claim 1, wherein,

The resin (B) is a difunctional acrylate monomer bonded to an acryl group at both ends of a linear structure composed of hydrocarbon groups or a difunctional acrylate monomer bonded to an acryl group at both ends of a linear structure having an ether bond.

9. A wire grid polarizing element as defined in claim 8, wherein,

The resin (B) is a difunctional acrylate monomer represented by the following chemical formula (I), and in the chemical formula (I), n is an integer of 1 to 9,

CH ₂＝CHCOO(CH ₂)_nOOCCH＝CH ₂…(I)。

10. A wire grid polarizing element as defined in claim 9, wherein,

In the chemical formula (I), n is an integer of 6 to 9.

11. A wire grid polarizing element as defined in claim 10, wherein,

In the chemical formula (I), n is 6 or 9.

12. A wire grid polarizing element as defined in claim 1, wherein,

The YI value of the cured product is 3 or less.

13. A wire grid polarizing element as defined in claim 1, wherein,

The storage modulus of the cured product at 120 ℃ is 3.9X10 ⁸ Pa or more.

14. A wire grid polarizing element as defined in claim 1, wherein,

15. A wire grid polarizing element as defined in claim 1, wherein,

16. A wire grid polarizing element as defined in claim 1, wherein,

The maximum width (W _MAX) of the functional film wrapping the raised strip is equal to or greater than the width (W _B) of the raised strip at a position 20% above the height of the raised strip from the bottom of the raised strip.

17. A wire grid polarizing element as defined in claim 1, wherein,

The convex structure body formed by the convex strip and the functional film has a cross-sectional shape, and a narrowed portion having a width narrowed in the width direction of the convex structure body is provided at a position immediately below the lower end portion of the functional film that surrounds the convex strip.

18. A wire grid polarizing element as defined in claim 1, wherein,

The product (Tp×Rs) of the transmission axis transmittance (Tp) and the reflection axis reflectance (Rs) of the incident light having an incident angle of 45 DEG with respect to the wire grid polarizing element is 70% or more.

19. A wire grid polarizing element as defined in claim 1, wherein,

The height (H) of the raised line is 160nm or more.

20. A wire grid polarizing element as defined in claim 1, wherein,

The thickness (Dt) of the functional film covering the tips of the raised strips is 5nm or more.

21. A wire grid polarizing element as defined in claim 1, wherein,

The functional film covering the side surfaces of the raised strips has a thickness (Ds) of 10nm to 30 nm.

22. A wire grid polarizing element as defined in claim 1, wherein,

The Thickness (TB) of the base portion is 1nm or more.

23. A wire grid polarizing element as defined in claim 1, wherein,

The cross-sectional shape of the ridge portion in a cross-section of the wire grid polarizing element orthogonal to the reflection axis is a trapezoid, triangle, bell, or ellipse whose width becomes narrower as it is distant from the base portion.

24. A wire grid polarizing element as defined in claim 1, wherein,

The functional film is also provided with a protective film formed so as to cover at least the surface of the functional film.

25. A wire grid polarizing element as recited in claim 24, wherein,

The protective film contains a water-repellent coating or an oil-repellent coating.

26. A wire grid polarizing element as defined in claim 1, wherein,

The functional film also has a dielectric film.

27. A wire grid polarizing element as defined in claim 1, wherein,

In the case where θ is 30 ° to 60 °,

The difference between the transmission axis transmittance (Tp (+)) of the incident light having an incident angle of +θ with respect to the wire grid polarizing element and the transmission axis transmittance (Tp (-)) of the incident light having an incident angle of- θ is 3% or less.

28. A wire grid polarizing element as defined in claim 1, wherein,

The functional film is a reflective film that reflects incident light.

29. A wire grid polarizing element as defined in claim 1, wherein,

The wire grid polarizing element is a polarizing beamsplitter that separates obliquely incident light into first and second polarized light.

30. A method of manufacturing a wire grid polarizer, comprising:

In the step of forming the functional film, the functional film is formed in such a manner that,

The functional film is wrapped around the front end and the upper side of at least one side surface of the ridge portion, and the base portion and the lower side of both side surfaces of the ridge portion are not wrapped, and when the wrapping rate (Rc) of the side surface of the ridge portion wrapped by the functional film is the ratio of the height (Hx) of the portion wrapped by the functional film to the height (H) of the ridge portion among the side surfaces of the ridge portion, the wrapping rate (Rc) is 30% to 70%,

The photopolymerizable component comprises:

A resin (A); and

A resin (B),

31. A method of manufacturing a wire grid polarizing element as defined in claim 30, wherein,

In the step of forming the functional film, film formation is performed alternately on the ridge portions from a plurality of directions by sputtering or vapor deposition.

32. A projection display device is characterized by comprising:

A light source;

A reflective liquid crystal display element configured to reflect and modulate the first polarized light or the second polarized light incident on the first polarized light reflected by the polarizing beam splitter or the second polarized light transmitted through the polarizing beam splitter; and

The polarizing beam splitter is comprised of the wire grid polarizing element of any one of claims 1 to 29.

33. The projection display device of claim 32, wherein the display device further comprises a display device,

The incidence angle in the predetermined range is 30 DEG to 60 deg.

34. The projection display device of claim 32, wherein the display device further comprises a display device,

A heat sink member is disposed around the wire grid polarizing element.

35. A vehicle comprising the projection display device according to claim 32.

36. An imprinting photocurable acrylic resin for use in the wire grid polarizing element according to any one of claims 1 to 29, and comprising a photopolymerizable component,

The photopolymerizable component comprises:

A resin (A); and

A resin (B),