JP6612109B2 - Optical member and manufacturing method thereof, display, and image display device - Google Patents

Description

  The present invention relates to a reflector and a manufacturing method thereof. The present invention also relates to an optical member including the reflective material, a display including the optical member, and an image display device including the display.

  In recent years, there is an increasing need for a system in which information such as characters or figures is input by handwriting on a display of an image display device, digitized, and input to an information processing device. In the form using an optical pen and a handwritten input sheet as the system, a handwritten input sheet having a layer in which information is written as an optical pattern and a reflective material can be used. Here, the reflective material is used to return the light emitted from the optical pen to the image sensor incorporated in the optical pen as light reflecting the information described as the optical pattern. For example, in Patent Document 1, an infrared reflection layer having a characteristic of reflecting infrared light from one side and transmitting visible light is arranged with pattern-like dots in which coordinate information and / or code information are repeatedly defined. There is a description about an information input auxiliary sheet provided together with the dot pattern layer.

JP 2014-089443 A

  An object of the present invention is to provide a novel reflector. This invention makes it a subject to provide the reflecting material which can be used especially for the said system. Another object of the present invention is to provide a novel optical member that can be used as the above-mentioned handwriting input sheet. It is another object of the present invention to provide a display and an image display device with high sensitivity for reading with an optical pen.

  The inventors of the present invention have attempted to solve the above problems by using a layer in which a cholesteric liquid crystal phase that has been conventionally known to be used as a reflecting member is fixed. In the process, we faced a problem that sensitivity was lowered especially when the optical pen was tilted. Since the layer in which the cholesteric liquid crystal phase is fixed has the property of exhibiting maximum reflectivity at a desired wavelength in the normal direction, the above problem is that of the layer in which the cholesteric liquid crystal phase is fixed at the wavelength of the infrared light used. It was thought to be derived from the low retroreflectivity in the oblique direction. As a result of the study, the present inventors have solved the above problem and completed the present invention.

That is, the present invention provides the following [1] to [20].
[1] including a circularly polarized light reflecting layer and an elastic organic layer,
The circularly polarized light reflection layer includes a layer in which a cholesteric liquid crystal phase is fixed,
The circularly polarized light reflection layer has an uneven shape,
The elastic organic layer is a reflective material in which one surface is in direct contact with the circularly polarized light reflecting layer and the other surface is a flat surface.
[2] including an uneven planarizing layer,
The uneven flattening layer, the circularly polarized light reflecting layer and the elastic organic layer are in this order,
The reflective material according to [1], wherein the uneven flattening layer is in direct contact with the circularly polarized light reflecting layer.
[3] The reflective material according to [2], wherein the uneven flattening layer is a microlens film.
[4] The reflective material according to [2], wherein the uneven flattening layer is a prism film or a lenticular sheet.
[5] The reflective material according to any one of [1] to [4], which includes a support on the flat surface side of the elastic organic layer.
[6] The reflective material according to any one of [1] to [5], which reflects light in an infrared wavelength region.

[7] The reflective material according to any one of [1] to [6], in which a haze value is 50% or less.
[8] An optical member including the reflecting material according to any one of [1] to [7] and an information presentation layer,
The information presentation layer is an optical member having a pattern of a material that absorbs or reflects light reflected by the reflective material.
[9] The optical member according to [8], wherein the pattern is a dot pattern.
[10] The optical member according to [8] or [9], wherein the pattern is formed by printing.
[11] A display having the optical member according to any one of [8] to [10].
[12] An image display device having the display according to [11].
[13] A method for producing a reflecting material according to any one of [1] to [7],
Preparing a laminate 10 comprising an elastic organic layer and a cholesteric liquid crystal layer;
The uneven surface of the substrate having an uneven surface is bonded to the surface of the laminate 10 on the cholesteric liquid crystal layer side to form the uneven surface on the elastic organic layer, and at the same time, the uneven surface of the substrate and the elastic organic Including making the cholesteric liquid crystal layer uneven with the uneven surface of the layer,
The production method, wherein the cholesteric liquid crystal layer of the laminate 10 is a layer obtained by curing or semi-curing a liquid crystal composition containing a polymerizable liquid crystal compound.
[14] The manufacturing method according to [13], wherein the bonding is vacuum bonding.

[15] The cholesteric liquid crystal layer is a layer obtained by semi-curing a liquid crystal composition containing the polymerizable liquid crystal compound, and includes heating or irradiating the laminate 10 after the formation of the concavo-convex shape. ] Or the production method according to [14].
[16] The production method according to [15], wherein the light is ultraviolet light and the light irradiation is performed at 100 mJ / cm ² or more.
[17] The production method according to any one of [13] to [16], comprising forming an elastic organic layer by applying an elastic organic layer forming material to a surface of the cholesteric liquid crystal layer.
[18] The laminate 10 includes a support, the elastic organic layer, and the cholesteric liquid crystal layer,
The preparation of the laminate 10 is such that the laminate 1 including the temporary support and the cholesteric liquid crystal layer and the laminate 2 including the support and the elastic organic layer are in contact with the cholesteric liquid crystal layer and the elastic organic layer surface. The manufacturing method according to any one of [13] to [16], which is performed by a method including laminating and temporary peeling of the temporary support after the laminating.
[19] The production method according to [18], wherein the elastic modulus of the elastic organic layer of the laminate 2 is 10 ³ to 10 ⁶ Pa at 30 ° C.
[20] The cholesteric liquid crystal layer is formed by applying a liquid crystal composition containing the polymerizable liquid crystal compound on the surface of the temporary support and irradiating the liquid crystal composition with ultraviolet rays of 50 mJ / cm ² or less. The production method according to [18] or [19].

  According to the present invention, a novel reflecting material and a manufacturing method thereof are provided. In particular, the present invention provides a reflective material that can be used in a system for inputting information such as characters or figures by handwriting on a display of an image display device, digitizing the information, and inputting the information to an information processing device. The optical member including the reflective material can be used as a handwritten input sheet in the above-described system. By using the optical member, it is possible to provide a display and an image display device with high sensitivity of reading with an optical pen.

It is a figure which shows typically the cross section of the example of the reflecting material of this invention. It is a figure which shows typically the example of the cross-sectional shape of an uneven | corrugated circularly polarized light reflection layer. It is a figure which shows typically the example of the shape of the uneven surface of the base material which has an uneven surface. It is a figure explaining the measuring method of the retroreflection signal strength performed in the Example. It is a photograph which shows the shape of the circularly polarized light reflection layer of the reflecting material produced in the Example. It is a figure which shows typically the example of the optical member of this invention arrange | positioned ahead of a display.

Hereinafter, the present invention will be described in detail.
In the present specification, “to” is used to mean that the numerical values described before and after it are included as a lower limit value and an upper limit value.
In this specification, for example, an angle such as “45 degrees”, “parallel”, “vertical”, or “orthogonal”, unless otherwise specified, has a difference from an exact angle within a range of less than 5 degrees. Means. The difference from the exact angle is preferably less than 4 degrees, and more preferably less than 3 degrees. Note that in this specification, an angle formed by a surface and a surface, a line and a surface, or a line and a line is represented by an acute angle (an angle of 90 degrees or less).

In the present specification, each numerical value, numerical value range, and qualitative expression (for example, the expression “same”, “constant”, “entire”) includes numerical values that generally include an allowable error in this technical field. Are to be interpreted as indicating numerical ranges and properties. For example, when the wavelength is “same”, the difference is within 5 nm.
When the film thickness of the circularly polarized light reflection layer (distance from one point in the layer to the other surface) is constant, it means that the difference is less than 0.5 μm.

In this specification, the “surface” of a layer refers to the main surface (front surface, back surface) of the layer.
In this specification, when the concavo-convex surfaces are complementary to each other, it means that the concavo-convex surfaces are in direct contact with each other over the entire concavo-convex surface. When the second layer is formed so as to fill the unevenness of the uneven surface of the first layer, a second layer having an uneven surface complementary to the uneven surface of the first layer is obtained. Further, the uneven surface of the first layer is complementary to the uneven surface of the obtained second layer.
In this specification, the values for the film thickness, the distance from one point in the layer to the other, the distance between the inclined surfaces 1 and the angle of the inclined surface are laser microscope, scanning electron microscope (SEM), transmission It is a value that can be measured in an image obtained with a microscope such as a scanning electron microscope (TEM).
In this specification, the “azimuth” means a direction in the plane of the reflecting material around the normal line of the reflecting material.
In this specification, “(meth) acrylate” is used to mean “one or both of acrylate and methacrylate”.

  In this specification, “sense” for circularly polarized light means right circularly polarized light or left circularly polarized light. The sense of circularly polarized light is right-handed circularly polarized light when the electric field vector tip turns clockwise as time increases when viewed as the light travels toward you, and left when it turns counterclockwise. Defined as being circularly polarized.

  In this specification, the term “sense” may be used for the twist direction of the spiral of the cholesteric liquid crystal. The selective reflection by the cholesteric liquid crystal reflects right circularly polarized light when the twist direction (sense) of the cholesteric liquid crystal spiral is right, transmits left circularly polarized light, and reflects left circularly polarized light when the sense is left, Transmits circularly polarized light.

  Visible light is light having a wavelength visible to the human eye among electromagnetic waves, and indicates light having a wavelength range of 380 nm to 780 nm. Infrared rays (infrared light) are electromagnetic waves in the wavelength range that are longer than visible rays and shorter than radio waves. Among infrared rays, near infrared light is an electromagnetic wave having a wavelength range of 780 nm to 2500 nm.

In this specification, the “haze value” means a value measured using a haze meter NDH-2000 manufactured by Nippon Denshoku Industries Co., Ltd.
Theoretically, the haze value means a value represented by the following formula.
(Scattering transmittance of non-polarized light (natural light) of 380 to 780 nm) / (unpolarized scattering transmittance of 380 to 780 nm + unpolarized parallel light transmittance of 380 to 780 nm) × 100%
The scattering transmittance is a value that can be calculated by subtracting the parallel light transmittance from the obtained omnidirectional transmittance using a spectrophotometer and an integrating sphere unit. The parallel light transmittance is a transmittance at 0 degrees when based on a value measured using an integrating sphere unit.
In the present specification, the term “reflected light” or “transmitted light” is used to mean scattered light and diffracted light.

In addition, the polarization state of each wavelength of light can be measured using a spectral radiance meter or a spectrometer equipped with a circularly polarizing plate. In this case, the intensity of light measured through the right circularly polarizing plate corresponds to I _R , and the intensity of light measured through the left circularly polarizing plate corresponds to I _L. In addition, ordinary light sources such as incandescent light bulbs, mercury lamps, fluorescent lamps, and LEDs emit almost non-polarized light. However, the characteristic of producing polarized light of films mounted on these light sources is, for example, a polarization phase difference analyzer manufactured by AXOMETRIC It can be measured using AxoScan or the like.
Moreover, even if a circularly polarized light transmission plate is attached to an illuminometer or a spectrum meter, it can be measured. The ratio can be measured by attaching a right circular polarized light transmission plate, measuring the right circular polarized light amount, attaching a left circular polarized light transmission plate, and measuring the left circular polarized light amount.

  In this specification, “transparent” means having a light transmittance of 40% or more, preferably 50% or more, more preferably 60% or more, and further preferably 70% or more in the visible light wavelength region. It means being. The light transmittance is the light transmittance determined by the method described in JIS-K7105.

<Reflecting material>
The reflective material may be a film shape, a sheet shape, or a plate shape. An example of a cross section of the reflector of the present invention is schematically shown in FIG.
The reflective material of the present invention includes a circularly polarized light reflective layer 1 and an elastic organic layer 2. The reflective material of the present invention preferably includes the uneven planarizing layer 3, and it is sufficient that the elastic organic layer 2, the circularly polarized reflective layer 1 and the uneven planarizing layer 3 are included in this order. Moreover, the reflective material of this invention may contain the support body 4, It is preferable that the support body 4, the elastic organic layer 2, the circular-polarized-light reflection layer 1, and the uneven | corrugated planarization layer 3 are this order.

[Optical properties of reflective material]
The reflective material of the present invention can reflect light in the infrared wavelength region. The wavelength of the infrared ray reflected by the reflecting material of the present invention is not particularly limited, but when the transmittance spectrum of the reflecting material is confirmed, the reflected wavelength band having a center wavelength in the range of 780 to 2000 nm, preferably in the range of 800 to 1500 nm. It is preferable that can be confirmed. It is also preferable that the reflection wavelength is selected according to the use of the reflective material. For example, it is preferable that the wavelength is selected according to the wavelength of a light source such as an optical pen used in combination or the wavelength of infrared rays sensed by a sensor of an image sensor. The half width of the reflection wavelength band is 50 to 500 nm, preferably 100 to 300 nm.

  The reflective material of the present invention has at least one incident surface with high retroreflectivity even when light is incident from a direction that forms an angle with the normal line of the reflective material. Retroreflection means reflection in which incident light is reflected in the incident direction. By having high retroreflectivity, high sensitivity can be obtained even when light is incident from an oblique angle with respect to the normal line of the reflector and the reflected light is detected from the same direction. For example, the reflective material of the present invention has the largest amount of retroreflected light when light having an angle of 45 degrees from the normal of the reflective material is incident on the incident surface from the specific surface side of the reflective material of the present invention. In terms of wavelength, the amount of retroreflected light is 15% or more of the amount of retroreflected light of a standard diffuser (manufactured by Labsphere). Said retroreflection can be obtained even if light is incident on the circularly polarized light reflecting layer from either the elastic organic layer side or the uneven flattening layer side. Further, an arrangement capable of obtaining retroreflection according to the purpose may be selected depending on the uneven shape and its direction. For example, in the reflective material having the configuration shown in FIG. 1, light is incident from the uneven flattening layer 3 side. This is preferable because a larger amount of retroreflected light can be obtained.

The haze value of the reflective material of the present invention is preferably 50% or less, and more preferably 30% or less.
The reflective material of the present invention is preferably transparent in the visible light region.

[Elastic organic layer]
The reflective material of the present invention includes an elastic organic layer. One surface of the elastic organic layer is in direct contact with the circularly polarized light reflecting layer, and the other surface is a flat surface. The flat surface is a plane having an average roughness (Ra value) of 1 μm square of less than 100 nm, preferably less than 50 nm. In this specification, the in-plane direction of each layer in the reflecting material or the reflecting material is a direction parallel to the in-plane direction of the flat surface.
The surface of the elastic organic layer that is in direct contact with the circularly polarized light reflecting layer has an uneven shape complementary to the surface of the circularly polarized light reflecting layer on the elastic organic layer side.

The elastic organic layer only needs to have an elastic deformability capable of following the uneven shape when forming the uneven shape of the circularly polarized light reflection layer. In addition, the term “when the concave / convex shape of the circularly polarized light reflection layer is formed” means that it includes the later-described step of forming the concave / convex shape of the cholesteric liquid crystal layer or the semi-cured cholesteric liquid crystal layer. Specifically, it is preferable that the elastic organic layer has a storage elastic modulus of 10 ³ to 10 ⁶ Pa when forming the uneven shape of the circularly polarized light reflection layer. Specifically, the storage elastic modulus is preferably 10 ³ to 10 ⁶ Pa at 30 ° C., more preferably 10 ³ to 10 ⁵ Pa at 30 ° C., and 10 ³ to 10 ⁴ Pa. Further preferred. Since the concavo-convex shape is formed usually in the range of 20 ° C. to 80 ° C., it is preferable that the storage elastic modulus within the above range is exhibited in this temperature range. The storage elastic modulus is measured, for example, for a laminate 2 including a support and an elastic organic layer, which will be described later, and the measured value may be in the above range.

Storage elastic modulus is a component stored in the object among the energy generated by external force and strain on the object, and appears when a steady state is reached when shear strain is applied to the material at a sine frequency. When the shear stress is decomposed into a component that is in phase with the strain (elastic component) and a component that is 90 ° behind the strain and phase (viscous component), the stress component that is in phase with the shear strain Divided.
Storage modulus can be measured with a rheometer. A specific example of the measurement method is that a measurement object is molded and laminated so as to have a thickness of about 1.5 mm, and then a rheometer (for example, a dynamic viscoelasticity measuring device NDS-1000 manufactured by Taisei Corporation) is used. It can be measured within a set temperature range under the measurement conditions of shear mode, frequency 1 Hz, and heating rate 5 ° C./min.

  The elastic organic layer of the reflective member of the present invention includes a layer that loses elasticity after forming the irregular shape of the circularly polarized light reflective layer. That is, in the reflecting member of the present invention, the elastic organic layer may not have the above storage elastic modulus. For example, the elastic organic layer is preferably an ultraviolet curable adhesive, but the uneven shape of the circularly polarized light reflecting layer may be formed before curing, may be cured after forming the uneven shape, and may lose the elasticity. In this specification, it is called an elastic organic layer regardless of whether the concavo-convex shape is formed or not.

It is also preferable that the elastic organic layer has an adhesive function or an adhesive function when forming the uneven shape of the circularly polarized light reflecting layer. This is because the elastic organic layer is preferably bonded so as to be in direct contact with the circularly polarized light reflection layer when the concavo-convex shape is formed.
The elastic organic layer is preferably transparent and has a small difference in refractive index from the circularly polarized reflective layer. This is to prevent haze from occurring due to the difference in refractive index when the irregular shape is formed on the elastic organic layer by the irregular shaping. The difference in refractive index is preferably 0.1 or less, more preferably 0.05 or less, and further preferably 0.02 or less.
Furthermore, the elastic organic layer is preferably low birefringent. In this specification, low birefringence means that the front phase difference is 10 nm or less at a wavelength of 550 nm. In this specification, the front phase difference is a value measured using an AxoScan manufactured by Axometrics.

  The material of the elastic organic layer is not particularly limited as long as the above properties are satisfied. For example, an ultraviolet curable adhesive can be used. Specific examples include KSM Co., Ltd. T-100, T-110, T-470, DIC Corporation Fine Tac RX-101, RX-102, RX-201, RX-301, Toa Gosei Co., Ltd. Aron Tac UVA-1000 Series , UVA-2000 series, UVA-3000 series, UVX5457, or Toa Gosei Co., Ltd. UVX5457 and a mixture of Tinuvin 400 (BASF) (for example, a mixture having a mass ratio of 1: 1).

  The elastic organic layer is formed, for example, by applying an elastic organic layer forming material on a support, or by applying directly to the surface of a circularly polarized reflective layer (including a cholesteric liquid crystal layer and a semi-cured cholesteric liquid crystal layer). Is done. Curing such as ultraviolet irradiation may be performed as necessary depending on the material. Curing is preferably performed after forming the irregular shape. It may be semi-cured before forming the uneven shape.

[Shape of circularly polarized reflective layer]
The reflecting material of the present invention includes a circularly polarized light reflecting layer. The circularly polarized light reflection layer in the reflective material of the present invention has an uneven shape.
The circularly polarized light reflecting layer preferably has alternately inclined 1 and inclined 2 whose directions are opposite to each other in one of the in-plane directions of the circularly polarized reflecting layer 1 (in-plane direction 1). The in-plane direction 1 may be any direction as long as the following properties are satisfied. In the present specification, the inclined surface 1 and the inclined surface 2 are used to indicate that the directions of inclination are opposite to each other in one in-plane direction. Both slope 1 and slope 2 are meant.

It is preferable that the inclination 1 is repeated at 1 μm or more and 500 μm or less. That is, it is preferable that at least one inclined surface 1 and at least one inclined surface 2 exist in the entire range divided by 500 μm in the in-plane direction 1. With such a configuration, the retroreflectivity without unevenness can be shown for light incident obliquely on the incident surface including the in-plane direction 1. The above repetition can be obtained as a distance between positions showing the maximum value of adjacent heights in the concavo-convex shape. This distance may be constant in the in-plane direction 1 or may vary randomly.
In addition, said distance shall be calculated | required using with the microscope image of sectional drawing of a reflector in the in-plane direction 1. FIG.

The maximum value of the angle formed by the inclination 1 and the flat surface is preferably 10 degrees or more and 60 degrees or less, and the maximum value of the angle formed by the inclination 2 and the flat surface is preferably 10 degrees or more and 60 degrees or less. The angles are more preferably 20 degrees or more and 50 degrees or less. By having an inclination of 10 degrees or more, the circularly polarized light reflecting layer can exhibit high retroreflectivity even when light is incident from a direction that makes an angle from the normal direction of the reflecting material. As described above, the inclination appears in the in-plane direction 1 so that the inclination directions are alternately opposite. Therefore, the circularly polarized light reflection layer 1 can exhibit high retroreflectivity even when light is incident from a direction that forms an angle with respect to the normal direction of the reflector in at least two directions that are in a linear direction. Further, since the inclination is 60 degrees or less, a cholesteric structure having a spiral axis direction perpendicular to the inclination is easily obtained.
In the case where the uneven shape is a curved surface, the determination is made based on the inclination of the tangent plane of the curved surface (the tangent to the curve in the cross-sectional view). That is, the maximum value of the angle formed by any tangent plane and the flat surface may be 10 degrees or more and 60 degrees or less.

The maximum value of the angle formed by the inclination 1 and the flat surface and the maximum value of the angle formed by the inclination 2 and the flat surface may be the same or different. In addition, the maximum value of the angle formed by the inclination 1 and the flat surface and the maximum value of the angle formed by the inclination 2 and the flat surface may each be constant in the in-plane direction 1 and are randomly changed. Also good.
These angles are the angle between the line corresponding to the flat surface and the inclination of the line corresponding to the surface of the circularly polarized light reflecting layer on the uneven flattening layer side in the microscopic image of the cross-sectional view of the reflector in the in-plane direction 1 Shall be obtained by measuring.

  That is, the circularly polarized light reflection layer has at least one in-plane direction (in-plane direction 1) having a cross section sandwiched between lines having alternately inclined lines and lines having alternately inclined lines. An example of this cross section of the circularly polarized light reflecting layer is schematically shown in FIG. For example, a semi-continuous line (FIGS. 2 (a), (b), (f), (g), (h)), a triangular wave (FIG. 2 (c)), a semi-circular and straight repeating line (FIG. 2D), sine wave (FIG. 2E), and the like.

  Further, the depth of the unevenness may be in the range of 2 μm or more and less than 200 μm, and is preferably in the range of 3 μm or more and less than 100 μm. The depth of the unevenness for each inclination in the in-plane direction 1 may be constant (other than (f) in FIG. 2) or may vary randomly (FIG. 2 (f)). In addition, what is necessary is just to measure the depth of an unevenness | corrugation by the curve corresponding to the surface by the side of the uneven | corrugated planarization layer of a circularly polarized light reflection layer. For a line having slopes alternately, for example, in the maximum value or the minimum value, the distance between the vertices of adjacent unevenness (distance between the convex maximum value and the adjacent convex maximum value) is constant in the in-plane direction 1 (FIG. 2). (Except for (f), (g), (h)), or may be changed randomly (FIGS. 2 (f), (g), (h)).

  The concavo-convex shape may be any concavo-convex shape in which concave portions having the same or substantially similar (including similar) cross-sectional shape are repeated. The repetition may be continuous, or may be intermittent as long as the distance between the positions showing the adjacent maximum values is satisfied. It is also preferable that the repeated cross-sectional shape is a line-symmetric shape.

One aspect of the uneven shape includes a surface that alternately includes the slope 1 and the slope 2 in the in-plane direction 2 perpendicular to the in-plane direction 1 of the circularly polarized light reflecting layer 1. Examples of such surfaces include a shape in which a hemisphere is two-dimensionally continuous, a shape in which corner cubes and prisms are two-dimensionally continuous, and the like. The hemisphere may have a flat surface side as the center of the sphere, and may have the opposite side as the center of the sphere.
In this aspect, high retroreflectivity with respect to the incidence of light from the direction that forms an angle from the normal line of the reflector as described above can be obtained in multiple directions.

As another embodiment of the uneven shape, there is an uneven shape that is a set of points where a straight line parallel to the in-plane direction 2 perpendicular to the in-plane direction 1 of the circularly polarized light reflection layer has a constant distance from the flat surface. Examples of the structure for providing such a surface include a lenticular shape (continuous shape of a semi-columnar body), a prism shape (a continuous shape of a triangular prism), a shape complementary to the lenticular shape, and the like.
In this embodiment, the reflective material is anisotropic in the retroreflective size. For example, on the incident surface including the direction in the reflector surface perpendicular to the ridgeline of the half columnar body or the triangular prism, the retroreflectivity with respect to the incidence of light from the direction that makes an angle from the normal line of the semicolumnar reflector as described above. Can be obtained most effectively. For example, when the angle between the straight line orthogonal to the ridge line and the component of the incident light or reflected light projected onto the reflecting material surface is φ in the reflecting material surface, when φ is 10 degrees or more, φ is 0 degree. In this case, the reflectance is 50% or less with respect to the retroreflectance with respect to the incidence of light from the same angle direction.

  The thickness of the circularly polarized light reflection layer may be 50 μm or less, 30 μm or less, 20 μm or less, or 10 μm or less, and may be a thickness of a selective reflection wavelength or more.

[Layer with fixed cholesteric liquid crystal phase]
The circularly polarized light reflection layer includes one or more layers in which the cholesteric liquid crystal phase is fixed. It is known that the cholesteric liquid crystal phase has a circularly polarized light selective reflection property that selectively reflects either right circularly polarized light or left circularly polarized light. Many films formed from a liquid crystal composition containing a liquid crystal compound have been known as films exhibiting circularly polarized light selective reflectivity. For layers in which a cholesteric liquid crystal phase is fixed, those conventional techniques can be referred to. it can.

The layer in which the cholesteric liquid crystal phase is fixed may be a layer in which the alignment of the liquid crystal compound in the cholesteric liquid crystal phase is maintained, and typically, the polymerizable liquid crystal compound is in the alignment state of the cholesteric liquid crystal phase. On the other hand, if it is a layer that has been polymerized and cured by ultraviolet irradiation, heating, etc. to form a layer having no fluidity, and at the same time, it has been changed to a state that does not cause changes in the orientation form due to an external field or external force Good. In the layer in which the cholesteric liquid crystal phase is fixed, it is sufficient that the optical properties of the cholesteric liquid crystal phase are maintained in the layer, and the liquid crystal compound in the layer may no longer exhibit liquid crystallinity. For example, the polymerizable liquid crystal compound may have a high molecular weight due to a curing reaction and may no longer have liquid crystallinity.
In this specification, a layer in which a cholesteric liquid crystal phase is fixed may be referred to as a cholesteric liquid crystal layer or a liquid crystal layer. Further, in this specification, a layer obtained by curing a liquid crystal composition containing a liquid crystal compound, a layer that is not a completely non-fluidic layer is sometimes referred to as a cholesteric liquid crystal layer. In particular, a semi-cured cholesteric liquid crystal layer may be distinguished from a layer in which a cholesteric liquid crystal phase is completely fixed.

  The cholesteric liquid crystal layer exhibits circularly polarized light selective reflection derived from the helical structure of the cholesteric liquid crystal. The central wavelength λ of the circularly polarized light selective reflection depends on the pitch P (= spiral period) of the helical structure in the cholesteric phase, and follows the relationship between the average refractive index n of the cholesteric liquid crystal layer and λ = n × P. Therefore, by adjusting the pitch of this spiral structure, the wavelength exhibiting circularly polarized light selective reflection can be adjusted. That is, in order to adjust the n value and the P value so as to exhibit circularly polarized light selective reflection in the near-infrared light wavelength region, the center wavelength λ is in the wavelength region of 750 nm to 2000 nm, preferably 800 nm to 1500 nm. You can do it. Since the pitch of the cholesteric liquid crystal phase depends on the type of chiral agent used together with the polymerizable liquid crystal compound or the concentration of the chiral agent, the desired pitch can be obtained by adjusting these. In the present specification, the center wavelength of selective reflection means the center wavelength when measured from the normal direction (helical axis direction) of the cholesteric liquid crystal layer.

In addition, the sense of the reflected circularly polarized light of the cholesteric liquid crystal layer coincides with the sense of the spiral. That is, a cholesteric liquid crystal layer with a spiral sense on the right reflects right circularly polarized light, and a cholesteric liquid crystal layer with a spiral sense on the left reflects left circularly polarized light. The circularly polarized light reflection layer may include either one of a cholesteric liquid crystal layer having a spiral sense on the right or a cholesteric liquid crystal layer having a spiral sense on the left, or may include both.
For the method of measuring spiral sense and pitch, use the methods described in “Introduction to Liquid Crystal Chemistry Experiments”, edited by the Japanese Liquid Crystal Society, Sigma Publishing 2007, page 46, and “Liquid Crystal Handbook”, Liquid Crystal Handbook Editing Committee, page 196. be able to.

  The half-value width Δλ (nm) of the selective reflection band (circular polarization reflection band) showing the circularly polarized selective reflection follows that ΔΔ depends on the birefringence Δn of the liquid crystal compound and the pitch P, and Δλ = Δn × P. . Therefore, the width of the selective reflection band can be controlled by adjusting Δn. Δn can be adjusted by adjusting the kind of the polymerizable liquid crystal compound and the mixing ratio thereof, or by controlling the temperature at the time of fixing the alignment.

In addition, the reflection center wavelength and half value width of a cholesteric liquid crystal layer can be calculated | required as follows.
When the transmission spectrum of the reflective material is measured using a spectrophotometer UV3150 (Shimadzu Corporation), a decrease in transmittance peak is observed in the selective reflection region. Of the two wavelengths having a transmittance of 1/2 the maximum peak height, the wavelength value on the short wave side is λ1 (nm) and the wavelength value on the long wave side is λ2 (nm). The reflection center wavelength and the half width can be expressed by the following formula.
Reflection center wavelength = (λ1 + λ2) / 2
Half width = (λ2−λ1)

  The half-value width of the circularly polarized light reflection band is usually about 50 nm to 150 nm for one kind of material. In order to widen the selection wavelength range, two or more cholesteric liquid crystal layers having different center wavelengths of reflected light with different periods P may be stacked. Alternatively, in one cholesteric liquid crystal layer, the control wavelength region can be widened by gradually changing the period P in the film thickness direction.

[Liquid crystal composition]
The cholesteric liquid crystal layer can be produced using a liquid crystal composition as a material. The liquid crystal composition includes a liquid crystal compound. The liquid crystal compound is preferably a polymerizable liquid crystal compound. The liquid crystal composition preferably contains a chiral agent and a horizontal alignment agent. The liquid crystal composition may further contain a surfactant or a polymerization initiator.

(Polymerizable liquid crystal compound)
The polymerizable liquid crystal compound may be a rod-like liquid crystal compound or a disk-like liquid crystal compound, but is preferably a rod-like liquid crystal compound.
Examples of the rod-like polymerizable liquid crystal compound forming the cholesteric liquid crystal layer include a rod-like nematic liquid crystal compound. Examples of rod-like nematic liquid crystal compounds include azomethines, azoxys, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines, alkoxy-substituted phenylpyrimidines. , Phenyldioxanes, tolanes and alkenylcyclohexylbenzonitriles are preferably used. Not only low-molecular liquid crystal compounds but also high-molecular liquid crystal compounds can be used.

  The polymerizable liquid crystal compound can be obtained by introducing a polymerizable group into the liquid crystal compound. Examples of the polymerizable group include an unsaturated polymerizable group, an epoxy group, and an aziridinyl group, preferably an unsaturated polymerizable group, and particularly preferably an ethylenically unsaturated polymerizable group. The polymerizable group can be introduced into the molecule of the liquid crystal compound by various methods. The number of polymerizable groups possessed by the polymerizable liquid crystal compound is preferably 1 to 6, more preferably 1 to 3. Examples of polymerizable liquid crystal compounds are described in Makromol. Chem. 190, 2255 (1989), Advanced Materials 5, 107 (1993), US Pat. No. 4,683,327, US Pat. No. 5,622,648, US Pat. No. 5,770,107, International Publication WO95 / 22586. No. 95/24455, No. 97/00600, No. 98/23580, No. 98/52905, JP-A-1-272551, No. 6-16616, and No. 7-110469. 11-80081 and JP-A 2001-328773, and the like. Two or more kinds of polymerizable liquid crystal compounds may be used in combination. When two or more kinds of polymerizable liquid crystal compounds are used in combination, the alignment temperature can be lowered.

  Moreover, it is preferable that the addition amount of the polymeric liquid crystal compound in a liquid-crystal composition is 80-99.9 mass% with respect to solid content mass (mass except a solvent) of a liquid-crystal composition, and 85-99. More preferably, it is 5 mass%, and it is especially preferable that it is 90-99 mass%.

(Chiral agent: optically active compound)
The chiral agent has a function of inducing a helical structure of a cholesteric liquid crystal phase. The chiral compound may be selected according to the purpose because the helical sense or helical pitch induced by the compound is different.
The chiral agent is not particularly limited, and known compounds (for example, liquid crystal device handbook, Chapter 3-4-3, TN, chiral agent for STN, page 199, Japan Society for the Promotion of Science, 142nd edition, 1989) Description), isosorbide, and isomannide derivatives can be used.

A chiral agent generally contains an asymmetric carbon atom, but an axially asymmetric compound or a planar asymmetric compound containing no asymmetric carbon atom can also be used as the chiral agent. Examples of the axial asymmetric compound or the planar asymmetric compound include binaphthyl, helicene, paracyclophane, and derivatives thereof. The chiral agent may have a polymerizable group. When both the chiral agent and the liquid crystal compound have a polymerizable group, they are derived from the repeating unit derived from the polymerizable liquid crystal compound and the chiral agent by a polymerization reaction between the polymerizable chiral agent and the polymerizable liquid crystal compound. A polymer having repeating units can be formed. In this aspect, the polymerizable group possessed by the polymerizable chiral agent is preferably the same group as the polymerizable group possessed by the polymerizable liquid crystal compound. Therefore, the polymerizable group of the chiral agent is also preferably an unsaturated polymerizable group, an epoxy group or an aziridinyl group, more preferably an unsaturated polymerizable group, and an ethylenically unsaturated polymerizable group. Particularly preferred.
The chiral agent may be a liquid crystal compound.
The content of the chiral agent in the liquid crystal composition is preferably 0.01% by mass to 200% by mass and more preferably 1% by mass to 30% by mass with respect to the amount of the polymerizable liquid crystal compound.

(Polymerization initiator)
The liquid crystal composition preferably contains a polymerization initiator. In the embodiment in which the polymerization reaction is advanced by ultraviolet irradiation, the polymerization initiator to be used is preferably a photopolymerization initiator that can start the polymerization reaction by ultraviolet irradiation. Examples of the photopolymerization initiator include α-carbonyl compounds (described in US Pat. Nos. 2,367,661 and 2,367,670), acyloin ether (described in US Pat. No. 2,448,828), α-hydrocarbon substituted aromatics. Group acyloin compounds (described in US Pat. No. 2,722,512), polynuclear quinone compounds (described in US Pat. Nos. 3,046,127 and 2,951,758), combinations of triarylimidazole dimers and p-aminophenyl ketone (US patents) No. 3549367), acridine and phenazine compounds (JP-A-60-105667, US Pat. No. 4,239,850), oxadiazole compounds (US Pat. No. 4,221,970), and the like. .
The content of the photopolymerization initiator in the liquid crystal composition is preferably 0.1 to 20% by mass, and preferably 0.5 to 5% by mass with respect to the content of the polymerizable liquid crystal compound. Further preferred.

(Crosslinking agent)
The liquid crystal composition may optionally contain a crosslinking agent in order to improve the film strength after curing and improve the durability. As the cross-linking agent, one that can be cured by ultraviolet rays, heat, moisture, or the like can be suitably used.
There is no restriction | limiting in particular as a crosslinking agent, According to the objective, it can select suitably, For example, polyfunctional acrylate compounds, such as a trimethylol propane tri (meth) acrylate and pentaerythritol tri (meth) acrylate; Glycidyl (meth) acrylate , Epoxy compounds such as ethylene glycol diglycidyl ether; aziridine compounds such as 2,2-bishydroxymethylbutanol-tris [3- (1-aziridinyl) propionate], 4,4-bis (ethyleneiminocarbonylamino) diphenylmethane; hexa Isocyanate compounds such as methylene diisocyanate and biuret type isocyanate; polyoxazoline compounds having an oxazoline group in the side chain; vinyltrimethoxysilane, N- (2-aminoethyl) 3-aminopropylto Alkoxysilane compounds such as methoxy silane. Moreover, a well-known catalyst can be used according to the reactivity of a crosslinking agent, and productivity can be improved in addition to membrane strength and durability improvement. These may be used individually by 1 type and may use 2 or more types together.
3 mass%-20 mass% are preferable, and, as for content of a crosslinking agent, 5 mass%-15 mass% are more preferable. When the content of the crosslinking agent is less than 3% by mass, the effect of improving the crosslinking density may not be obtained. When the content exceeds 20% by mass, the stability of the cholesteric liquid crystal layer may be decreased.

(Horizontal alignment agent)
In the liquid crystal composition, a horizontal alignment agent as an alignment control agent that contributes to stably or rapidly forming a cholesteric liquid crystal layer having a planar alignment may be added. Examples of the horizontal alignment agent include fluorine (meth) acrylate polymers described in paragraphs [0018] to [0043] of JP-A-2007-272185, and paragraphs [0031] to [0034] of JP-A-2012-203237. Etc.] and the compounds represented by the formulas (I) to (IV).
In addition, as a horizontal alignment agent, 1 type may be used independently and 2 or more types may be used together.

  The addition amount of the horizontal alignment agent in the liquid crystal composition is preferably 0.01% by mass to 10% by mass, more preferably 0.01% by mass to 5% by mass with respect to the total mass of the polymerizable liquid crystal compound. 0.02% by mass to 1% by mass is particularly preferable.

(Other additives)
In addition, the liquid crystal composition may contain at least one selected from a surfactant for adjusting the surface tension of the coating film to make the film thickness uniform, and various additives such as a polymerizable monomer. . Further, in the liquid crystal composition, if necessary, a polymerization inhibitor, an antioxidant, an ultraviolet absorber, a light stabilizer, a colorant, metal oxide fine particles, and the like may be added as long as the optical performance is not deteriorated. Can be added.

(solvent)
The liquid crystal composition may contain a solvent. There is no restriction | limiting in particular as a solvent used for preparation of a liquid-crystal composition, Although it can select suitably according to the objective, An organic solvent is used preferably.
The organic solvent is not particularly limited and may be appropriately selected depending on the intended purpose. For example, ketones, alkyl halides, amides, sulfoxides, heterocyclic compounds, hydrocarbons, esters, ethers, etc. Is mentioned. These may be used individually by 1 type and may use 2 or more types together. Among these, ketones are particularly preferable in consideration of environmental load.

[Production Method of Circularly Polarized Reflective Layer]
The circularly polarized light reflection layer in the reflective material of the present invention can be produced, for example, by any of the following procedures.

(Procedure 1-1)
(1) applying a liquid crystal composition on a temporary support;
(2) drying the liquid crystal composition coated on the temporary support;
(3) curing the dried liquid crystal composition to provide a cholesteric liquid crystal layer;
(4) An elastic organic layer is provided on the surface of the cholesteric liquid crystal layer obtained after (3) above;
(5) providing a support on the elastic organic layer;
(6) peeling off the temporary support;
(7) The uneven surface of the substrate having an uneven surface is bonded to the release surface to form an elastic organic layer having the uneven surface, and at the same time, the uneven surface of the substrate and the uneven surface of the elastic organic layer The cholesteric liquid crystal layer is formed in an uneven shape.

(Procedure 1-2)
(1) applying a liquid crystal composition on a temporary support;
(2) drying the liquid crystal composition coated on the temporary support;
(3) semi-curing the dried liquid crystal composition to provide a semi-cured cholesteric liquid crystal layer;
(4) An elastic organic layer is provided by applying an elastic organic layer forming material to the surface of the semi-cured cholesteric liquid crystal layer obtained after (3) above;
(5) providing a support on the elastic organic layer;
(6) peeling off the temporary support;
(7) The uneven surface of the substrate having an uneven surface is bonded to the release surface to form an elastic organic layer having the uneven surface, and at the same time, the uneven surface of the substrate and the uneven surface of the elastic organic layer Make the cholesteric liquid crystal layer uneven
(8) The laminated body obtained after the above (7) is heated or irradiated with light to cure the semi-cured cholesteric liquid crystal layer and / or the elastic organic layer to obtain an uneven circularly polarized light reflecting layer.

(Procedure 1-3)
(1) applying a liquid crystal composition on a temporary support;
(2) drying the liquid crystal composition coated on the temporary support;
(3) The dried liquid crystal composition is cured or semi-cured to provide a cholesteric liquid crystal layer or a semi-cured cholesteric liquid crystal layer;
(4) An elastic organic layer-forming material is applied to the surface of the cholesteric liquid crystal layer or semi-cured cholesteric liquid crystal layer obtained after the above (3) to provide an elastic organic layer;
(5) providing a support on the elastic organic layer;
(6) peeling off the temporary support;
(7) The uneven surface of the substrate having an uneven surface is bonded to the release surface to form an elastic organic layer having the uneven surface, and at the same time, the uneven surface of the substrate and the uneven surface of the elastic organic layer Make the cholesteric liquid crystal layer uneven
(8) Peeling the substrate having an uneven surface;
(9) An overcoat layer is provided on the cholesteric liquid crystal layer having an uneven surface;
(10) The laminated body obtained after the above (9) is heated or irradiated with light to cure the semi-cured cholesteric liquid crystal layer and / or the elastic organic layer and the overcoat layer to obtain a concavo-convex circularly polarized reflective layer.

(Procedure 1-4)
(1) applying a liquid crystal composition on a temporary support;
(2) drying the liquid crystal composition coated on the temporary support;
(3) The dried liquid crystal composition is cured or semi-cured to provide a cholesteric liquid crystal layer or a semi-cured cholesteric liquid crystal layer;
(4) An elastic organic layer-forming material is applied to the surface of the cholesteric liquid crystal layer or semi-cured cholesteric liquid crystal layer obtained after the above (3) to provide an elastic organic layer;
(5) providing a support on the elastic organic layer;
(6) peeling off the temporary support;
(7) The uneven surface of the substrate having an uneven surface is bonded to the release surface to form an elastic organic layer having the uneven surface, and at the same time, the uneven surface of the substrate and the uneven surface of the elastic organic layer Make the cholesteric liquid crystal layer uneven
(8) Peeling the substrate having an uneven surface;
(9) A plastic film is provided on the cholesteric liquid crystal layer having an uneven surface through an adhesive or an adhesive;
(10) If necessary, the laminate obtained after the above (9) is heated or irradiated with light to cure the semi-cured cholesteric liquid crystal layer and / or the elastic organic layer, and the pressure-sensitive adhesive or adhesive, thereby forming an uneven shape. A circularly polarized light reflection layer is obtained.

(Procedure 2-1)
(1) applying a liquid crystal composition on a temporary support;
(2) drying the liquid crystal composition coated on the temporary support;
(3) The dried liquid crystal composition is cured or semi-cured to provide a cholesteric liquid crystal layer or a semi-cured cholesteric liquid crystal layer;
(4) An elastic organic layer-forming material is applied to the surface of the cholesteric liquid crystal layer or semi-cured cholesteric liquid crystal layer obtained after the above (3) to provide an elastic organic layer;
(5) Curing or semi-curing the elastic organic layer;
(6) providing a support on the elastic organic layer;
(7) peeling the temporary support;
(8) The uneven surface of the substrate having an uneven surface is bonded to the release surface to form an elastic organic layer having an uneven surface, and at the same time, the uneven surface of the substrate and the uneven surface of the elastic organic layer The cholesteric liquid crystal layer is formed in an uneven shape.

(Procedure 2-2)
(1) applying a liquid crystal composition on a temporary support;
(2) drying the liquid crystal composition coated on the temporary support;
(3) The dried liquid crystal composition is cured or semi-cured to provide a cholesteric liquid crystal layer or a semi-cured cholesteric liquid crystal layer;
(4) An elastic organic layer-forming material is applied to the surface of the cholesteric liquid crystal layer or semi-cured cholesteric liquid crystal layer obtained after the above (3) to provide an elastic organic layer;
(5) Curing or semi-curing the elastic organic layer;
(6) providing a support on the elastic organic layer;
(7) peeling the temporary support;
(8) The uneven surface of the substrate having an uneven surface is bonded to the release surface to form an elastic organic layer having an uneven surface, and at the same time, the uneven surface of the substrate and the uneven surface of the elastic organic layer Make the cholesteric liquid crystal layer uneven
(9) The laminated body obtained after the above (8) is heated or irradiated with light to cure the semi-cured cholesteric liquid crystal layer and / or the semi-cured elastic organic layer to obtain a concavo-convex circularly polarized reflective layer.
(Procedure 2-3)
(1) applying a liquid crystal composition on a temporary support;
(2) drying the liquid crystal composition coated on the temporary support;
(3) The dried liquid crystal composition is cured or semi-cured to provide a cholesteric liquid crystal layer or a semi-cured cholesteric liquid crystal layer;
(4) An elastic organic layer-forming material is applied to the surface of the cholesteric liquid crystal layer or semi-cured cholesteric liquid crystal layer obtained after the above (3) to provide an elastic organic layer;
(5) Curing or semi-curing the elastic organic layer;
(6) providing a support on the elastic organic layer;
(7) peeling the temporary support;
(8) The uneven surface of the substrate having an uneven surface is bonded to the release surface to form an elastic organic layer having an uneven surface, and at the same time, the uneven surface of the substrate and the uneven surface of the elastic organic layer The cholesteric liquid crystal material layer has an irregular shape between
(9) Peeling the substrate having an uneven surface;
(10) An overcoat layer is provided on the cholesteric liquid crystal layer having an uneven surface;
(11) The laminated body obtained after the above (10) is heated or irradiated with light to cure the semi-cured cholesteric liquid crystal layer and / or the semi-cured elastic organic layer and the overcoat layer, thereby forming a concavo-convex circularly polarized reflective layer. obtain.

(Procedure 2-4)
(1) applying a liquid crystal composition on a temporary support;
(2) drying the liquid crystal composition coated on the temporary support;
(3) The dried liquid crystal composition is cured or semi-cured to provide a cholesteric liquid crystal layer or a semi-cured cholesteric liquid crystal layer;
(4) An elastic organic layer-forming material is applied to the surface of the cholesteric liquid crystal layer or semi-cured cholesteric liquid crystal layer obtained after the above (3) to provide an elastic organic layer;
(5) Curing or semi-curing the elastic organic layer;
(6) providing a support on the elastic organic layer;
(7) peeling the temporary support;
(8) The uneven surface of the substrate having an uneven surface is bonded to the release surface to form an elastic organic layer having an uneven surface, and at the same time, the uneven surface of the substrate and the uneven surface of the elastic organic layer Between the cholesteric liquid crystal layer or the semi-cured cholesteric liquid crystal layer,
(9) Peeling the substrate having an uneven surface;
(10) A plastic film is provided on the cholesteric liquid crystal layer or semi-cured cholesteric liquid crystal layer having an uneven surface through an adhesive or an adhesive;
(11) If necessary, the laminate obtained after the above (10) is heated or irradiated with light to cure the semi-cured cholesteric liquid crystal layer and / or the elastic organic layer, the pressure-sensitive adhesive or the adhesive, thereby forming an uneven circle. A polarization reflection layer is obtained.

(Procedure 3-1)
(1) applying a liquid crystal composition on a temporary support;
(2) The liquid crystal composition applied on the temporary support is dried to obtain the laminate 1;
(3) The laminate 1 is heated or irradiated with light to cure the liquid crystal composition to obtain a cholesteric liquid crystal layer;
(4) preparing a laminate 2 including a support and an elastic organic layer;
(5) The laminate 2 is provided so that the elastic organic layer contacts the surface of the cholesteric liquid crystal layer of the laminate 1;
(6) peeling off the temporary support;
(7) The uneven surface of the substrate having an uneven surface is bonded to the release surface to form an elastic organic layer having the uneven surface, and at the same time, the uneven surface of the substrate and the uneven surface of the elastic organic layer The cholesteric liquid crystal layer is formed in an uneven shape.

(Procedure 3-2)
(1) applying a liquid crystal composition on a temporary support;
(2) The liquid crystal composition applied on the temporary support is dried to obtain the laminate 1;
(3) The laminate 1 is heated or irradiated with light to cure or semi-cure the liquid crystal composition to obtain a cholesteric liquid crystal layer or a semi-cured cholesteric liquid crystal layer;
(4) preparing a laminate 2 including a support and an elastic organic layer;
(5) The laminate 2 is provided so that the elastic organic layer contacts the cholesteric liquid crystal layer or the semi-cured cholesteric liquid crystal layer surface of the laminate 1;
(6) peeling off the temporary support;
(7) The uneven surface of the substrate having an uneven surface is bonded to the release surface to form an elastic organic layer having the uneven surface, and at the same time, the uneven surface of the substrate and the uneven surface of the elastic organic layer Make the cholesteric liquid crystal layer uneven
(8) The laminated body obtained after the above (7) is heated or irradiated with light to cure the semi-cured cholesteric liquid crystal layer and / or the elastic organic layer to obtain an uneven circularly polarized light reflecting layer.

(Procedure 3-3)
(1) applying a liquid crystal composition on a temporary support;
(2) The liquid crystal composition applied on the temporary support is dried to obtain the laminate 1;
(3) The laminate 1 is heated or irradiated with light to cure or semi-cure the liquid crystal composition to obtain a cholesteric liquid crystal layer or a semi-cured cholesteric liquid crystal layer;
(4) preparing a laminate 2 including a support and an elastic organic layer;
(5) The laminate 2 is provided so that the elastic organic layer is in contact with the surface of the cholesteric liquid crystal layer or the semi-cured cholesteric liquid crystal layer of the laminate 1;
(6) peeling off the temporary support;
(7) The uneven surface of the substrate having an uneven surface is bonded to the release surface to form an elastic organic layer having the uneven surface, and at the same time, the uneven surface of the substrate and the uneven surface of the elastic organic layer Make the cholesteric liquid crystal layer uneven
(8) Peeling the substrate having an uneven surface;
(9) An overcoat layer is provided on the cholesteric liquid crystal layer having an uneven surface;
(10) The laminated body obtained after the above (9) is heated or irradiated with light to cure the semi-cured cholesteric liquid crystal layer and / or the elastic organic layer and the overcoat layer to obtain a concavo-convex circularly polarized reflective layer.

(Procedure 3-4)
(1) applying a liquid crystal composition on a temporary support;
(2) The liquid crystal composition applied on the temporary support is dried to obtain the laminate 1;
(3) The laminate 1 is heated or irradiated with light to cure or semi-cure the liquid crystal composition to obtain a cholesteric liquid crystal layer or a semi-cured cholesteric liquid crystal layer;
(4) preparing a laminate 2 including a support and an elastic organic layer;
(5) The laminate 2 is provided so that the elastic organic layer is in contact with the surface of the cholesteric liquid crystal layer or the semi-cured cholesteric liquid crystal layer of the laminate 1;
(6) peeling off the temporary support;
(7) The uneven surface of the substrate having an uneven surface is bonded to the release surface to form an elastic organic layer having the uneven surface, and at the same time, the uneven surface of the substrate and the uneven surface of the elastic organic layer Make the cholesteric liquid crystal layer uneven
(8) Peeling the substrate having an uneven surface;
(9) A plastic film is provided on the cholesteric liquid crystal layer having an uneven surface through an adhesive or an adhesive;
(10) If necessary, the laminate obtained after the above (9) is heated or irradiated with light to cure the semi-cured cholesteric liquid crystal layer and / or the elastic organic layer, the pressure-sensitive adhesive or the adhesive, thereby forming an uneven circle. A polarization reflection layer is obtained.

(Procedure 4-1)
(1) applying a liquid crystal composition on a temporary support;
(2) The liquid crystal composition applied on the temporary support is dried to obtain the laminate 1;
(3) The laminate 1 is heated or irradiated with light to cure the liquid crystal composition to obtain a cholesteric liquid crystal layer;
(4) preparing a laminate 2 including a support and an elastic organic layer;
(5) Curing or semi-curing the laminate 2;
(6) The laminate 2 is provided so that the elastic organic layer is in contact with the surface of the cholesteric liquid crystal layer of the laminate 1;
(7) peeling the temporary support;
(8) The uneven surface of the substrate having an uneven surface is bonded to the release surface to form an elastic organic layer having an uneven surface, and at the same time, the uneven surface of the substrate and the uneven surface of the elastic organic layer The cholesteric liquid crystal layer is formed in an uneven shape.

(Procedure 4-2)
(1) applying a liquid crystal composition on a temporary support;
(2) The liquid crystal composition applied on the temporary support is dried to obtain the laminate 1;
(3) The laminate 1 is heated or irradiated with light to cure or semi-cure the liquid crystal composition to obtain a cholesteric liquid crystal layer or a semi-cured cholesteric liquid crystal layer;
(4) preparing a laminate 2 including a support and an elastic organic layer;
(5) Curing or semi-curing the laminate 2;
(6) The laminate 2 is provided so that the elastic organic layer is in contact with the surface of the cholesteric liquid crystal layer or semi-cured cholesteric liquid crystal layer of the laminate 1;
(7) peeling the temporary support;
(8) The uneven surface of the substrate having an uneven surface is bonded to the release surface to form an elastic organic layer having an uneven surface, and at the same time, the uneven surface of the substrate and the uneven surface of the elastic organic layer Between the cholesteric liquid crystal layer or the semi-cured cholesteric liquid crystal layer,
(9) The laminated body obtained after the above (8) is heated or irradiated with light to cure the semi-cured cholesteric liquid crystal layer and / or the elastic organic layer to obtain a concavo-convex circularly polarized reflective layer.

(Procedure 4-3)
(1) applying a liquid crystal composition on a temporary support;
(2) The liquid crystal composition applied on the temporary support is dried to obtain the laminate 1;
(3) The laminate 1 is heated or irradiated with light to cure or semi-cure the liquid crystal composition to obtain a cholesteric liquid crystal layer or a semi-cured cholesteric liquid crystal layer;
(4) preparing a laminate 2 including a support and an elastic organic layer;
(5) Curing or semi-curing the laminate 2;
(6) The laminate 2 is provided so that the elastic organic layer is in contact with the surface of the cholesteric liquid crystal layer or semi-cured cholesteric liquid crystal layer of the laminate 1;
(7) peeling the temporary support;
(8) The uneven surface of the substrate having an uneven surface is bonded to the release surface to form an elastic organic layer having an uneven surface, and at the same time, the uneven surface of the substrate and the uneven surface of the elastic organic layer Between the cholesteric liquid crystal layer or the semi-cured cholesteric liquid crystal layer,
(9) Peeling the substrate having an uneven surface;
(10) An overcoat layer is provided on the cholesteric liquid crystal layer having an uneven surface;
(11) The laminated body obtained after the above (10) is heated or irradiated with light to cure the semi-cured cholesteric liquid crystal layer and / or the elastic organic layer and the overcoat layer to obtain a concavo-convex circularly polarized reflective layer.

(Procedure 4-4)
(1) applying a liquid crystal composition on a temporary support;
(2) The liquid crystal composition applied on the temporary support is dried to obtain the laminate 1;
(3) The laminate 1 is heated or irradiated with light to cure or semi-cure the liquid crystal composition to obtain a cholesteric liquid crystal layer or a semi-cured cholesteric liquid crystal layer;
(4) preparing a laminate 2 including a support and an elastic organic layer;
(5) Curing or semi-curing the laminate 2;
(6) The laminate 2 is provided so that the elastic organic layer is in contact with the surface of the cholesteric liquid crystal layer or semi-cured cholesteric liquid crystal layer of the laminate 1;
(7) peeling the temporary support;
(8) The uneven surface of the substrate having an uneven surface is bonded to the release surface to form an elastic organic layer having an uneven surface, and at the same time, the uneven surface of the substrate and the uneven surface of the elastic organic layer Between the cholesteric liquid crystal layer or the semi-cured cholesteric liquid crystal layer,
(9) Peeling the substrate having an uneven surface;
(10) A plastic film is provided on the cholesteric liquid crystal layer having an uneven surface via an adhesive or an adhesive;
(11) If necessary, the laminate obtained after the above (10) is heated or irradiated with light to cure the semi-cured cholesteric liquid crystal layer and / or the elastic organic layer and the pressure-sensitive adhesive or adhesive, thereby forming an uneven circle. A polarization reflection layer is obtained.

  In the above procedure, the laminate 2 including the support and the elastic organic layer is prepared by applying the elastic organic layer forming material on the support, or further curing or semi-curing the applied elastic organic layer forming material. ,It can be carried out.

  When producing a circularly polarizing reflective layer having two or more cholesteric liquid crystal layers, a plurality of semi-cured cholesteric liquid crystal layers or a plurality of cholesteric liquid crystal layers are formed by repeating the steps of applying, drying and semi-curing or curing the liquid crystal composition. And what is necessary is just to bond the base material which has an uneven surface with respect to this.

The substrate having an uneven surface used may be an uneven flattened layer as it is, or the substrate having an uneven surface may be peeled off and an overcoat layer may be provided on the peeled surface. A plastic film or the like may be bonded to the surface with an adhesive or an adhesive.
When peeling a base material, the peeling may be performed before hardening of a semi-hardened cholesteric liquid crystal layer, and may be performed after hardening. When the substrate is peeled before curing, for example, light irradiation for forming an overcoat layer with a curable resin may be light irradiation for curing the liquid crystal composition.

  Hereinafter, each step in the method for producing the circularly polarized light reflection layer and other materials used will be described.

(Application)
The application method of the liquid crystal composition is not particularly limited and can be appropriately selected depending on the purpose. For example, a wire bar coating method, a curtain coating method, an extrusion coating method, a direct gravure coating method, a reverse gravure coating method, a die Examples thereof include a coating method, a spin coating method, a dip coating method, a spray coating method, and a slide coating method.

(Drying, orientation)
The applied liquid crystal composition may be dried by leaving it as it is or by heating. The heating temperature is preferably 200 ° C. or lower, and more preferably 130 ° C. or lower. Liquid crystal molecules can be aligned in the course of drying the liquid crystal composition.

(Bonding)
Bonding may be performed by bringing the cholesteric liquid crystal layer obtained after curing or semi-curing of the liquid crystal composition into direct contact with the uneven surface of the substrate or material having the uneven surface. At this time, it is only necessary that the cholesteric liquid crystal layer is in contact with the surface of the uneven surface so as to fill the recessed portion of the uneven surface. As a result, the entire uneven surface shape of the substrate or material having the uneven surface can be transferred to the surface of the cholesteric liquid crystal layer. Alternatively, there may be a gap between the uneven surface and the liquid crystal composition. Thereby, a part of the uneven surface shape of the substrate or material having the uneven surface can be transferred to the surface of the cholesteric liquid crystal layer.
Examples of the void include a void larger than 0 and not more than 50% of a volume (volume of liquid that can fill the depressed portion) formed by the depressed portion of the concave portion of the uneven surface of the base material. The location of the gap is not limited, but may be, for example, the bottom of the recessed portion.

The cholesteric liquid crystal layer (semi-cured cholesteric liquid crystal layer) obtained by semi-curing the liquid crystal composition is not sufficiently cured at the time of bonding and has fluidity, so that the uneven surface of the substrate can be efficiently and highly accurately formed. The shape and the like can be transferred. Here, the state having fluidity means a state in which a trace of a fingerprint remains when light pressure is applied with a fingertip and the adhesiveness is exhibited.
The substrate or material having the concavo-convex surface or the cholesteric liquid crystal layer surface may be heated before contact so that the entire surface of the concavo-convex surface can be efficiently contacted. Heating is preferably performed at 40 ° C. to 110 ° C., more preferably 50 ° C. to 100 ° C. More preferably, the heating is performed on both the cholesteric liquid crystal layer and the substrate or material having an uneven surface. You may pressurize in the case of pasting. The pressurization may be performed at, for example, 0.05 to 60 MPa, preferably 0.05 to 20 MPa.

  The pressurization time is preferably 0.01 seconds or more and 20 seconds or less, more preferably 0.01 seconds or more and 10 seconds or less, and further preferably 0.01 seconds or more and 5 seconds or less. If it is 0.01 seconds or longer, the surface shape can be sufficiently transferred, and if it is 20 seconds or less, good productivity can be secured.

  Moreover, it is also preferable to perform bonding under vacuum. What is necessary is just to perform vacuum bonding within the low pressure of 1000 Pa or less. More preferably, the pressure is 100 Pa or less. For example, vacuum bonding may be performed within a pressure time of 0.1 to 60 minutes within a pressure range of 0.01 to 1000 MPa under the above pressure condition within a temperature range of 20 to 80 ° C. The vacuum bonding can be performed using, for example, a vacuum bonding machine V-SE6055aa commercially available from Climb Products.

(Curing)
The liquid crystal composition is cured to form a cholesteric liquid crystal layer. Except for the case of being semi-cured, a layer having no fluidity of the liquid crystal composition is formed by curing.
Curing may be either thermal curing or photocuring by light irradiation, but photocuring is preferred. It is preferable to use ultraviolet rays for light irradiation. The irradiation energy is preferably ^{20mJ / cm 2 ~50J / cm 2} , 100mJ / cm 2 ~1,500mJ / cm 2 is more preferable. In order to accelerate the photopolymerization reaction, light irradiation may be performed under heating conditions or in a nitrogen atmosphere. The irradiation ultraviolet wavelength is preferably 350 nm to 430 nm. The polymerization reaction rate is preferably high from the viewpoint of stability, preferably 70% or more, and more preferably 80% or more.
The polymerization reaction rate of the polymerizable liquid crystal compound in the liquid crystal composition by curing can be determined by measuring the consumption ratio of the polymerizable functional group using the IR absorption spectrum.

  When forming a cholesteric liquid crystal layer that is flat and not concave and convex, the liquid crystal molecules are aligned in the drying step described above, and the polymerizable liquid crystal compound has a helical axis in a direction perpendicular to the surface of the substrate or the like. A layer that is twisted and oriented to have The amount of retroreflected light in the circularly polarized light selective reflection band of the cholesteric liquid crystal layer becomes maximum when light is incident from the normal direction (= helical axis direction) of the cholesteric liquid crystal layer, and light from a direction that makes an angle from the normal direction. There is almost no retroreflected light amount for the incident light. That is, high retroreflectivity is exhibited only in the normal direction of the layer. In the reflective material of the present invention, the cholesteric liquid crystal layer is provided with a concavo-convex shape, and the circularly polarized light reflective layer has a concavo-convex shape, so that the spiral axis direction is an angle from the normal direction of the reflective material. Reflecting structure (for example, a structure in which the normal direction of the inclined surface of the concavo-convex surface is the spiral axis direction) is generated, and the reflector is highly retroreflective with respect to the incidence of light from a direction that makes an angle from the normal direction. Can be obtained.

(Semi-cured)
As used herein, “semi-cured” means cured while leaving the fluidity of the composition to be cured. In particular, the “semi-curing” of the liquid crystal composition is a kind of “curing” of the liquid crystal composition, but the liquid crystal composition is cured by additional heating or light irradiation until the non-flowable cholesteric liquid crystal layer is completed. Means curing. A “semi-cured cholesteric liquid crystal layer” obtained by “semi-curing” a liquid crystal composition means a layer having fluidity, although a part of the polymerizable group of the polymerizable liquid crystal compound in the liquid crystal composition is reacted. . In the production of the reflective material of the present invention, a substrate having an uneven surface is bonded to a semi-cured cholesteric liquid crystal layer, and after forming an uneven shape, it is further subjected to a curing step to form a circularly polarized reflective layer having an uneven shape. May be.

When the liquid crystal composition is a photopolymerizable liquid crystal composition, semi-curing can be performed by irradiation with ultraviolet rays of 50 mJ / cm ² or less. UV irradiation during the semi-curing is preferably 30 mJ / cm ² or less, more preferably 10 mJ / cm ² or less, and more preferably 5 mJ / cm ² or less. The ultraviolet radiation during the semi-curing, 0.1 mJ / cm ² or more, it is sufficient 0.2 mJ / cm ² or more, or 0.3 mJ / cm ² or more. In the ultraviolet irradiation, it is preferable that the oxygen concentration is 0.005% or more and 20% or less. Moreover, ultraviolet rays should just be light with a wavelength of 350-430 nm.

(Base material with uneven surface)
The uneven surface of the substrate having an uneven surface is complementary to the uneven shape of the circularly polarized light reflecting layer in the reflector of the present invention. As a base material which has an uneven surface, the base material which has an uneven surface among the uneven | corrugated planarization layer mentioned later can be used, for example.
Moreover, when peeling the said base material from a liquid-crystal composition, arbitrary materials (metal mold | die etc.) which have a desired uneven surface can also be used.
Examples of the uneven surface include a shape in which a hemisphere is two-dimensionally continuous, a shape in which corner cubes and prisms are two-dimensionally continuous (FIGS. 3A and 3B, or any one of these shapes). Complementary uneven surface shape). Further, there is a one-dimensional continuous uneven surface (FIG. 3 (c), (d), or an uneven surface shape complementary to any one of these shapes).

(Temporary support)
The temporary support is used as a substrate on which the liquid crystal composition is applied. The temporary support body should just be peeled off after sticking mentioned below or after hardening. When the reflective material of the present invention is used as a constituent member of an optical member, the temporary support may be peeled off after an information presentation layer described later is formed on the reflective material of the present invention having the temporary support.

As the temporary support, a plastic film such as polyester such as polyethylene terephthalate (PET), polycarbonate, acrylic resin, epoxy resin, polyurethane, polyamide, polyolefin, cellulose derivative, silicone, or glass can be used.
The film thickness of the temporary support may be about 5 μm to 1000 μm, preferably 10 μm to 250 μm, and more preferably 15 μm to 90 μm.

  An alignment layer may be formed on the surface side of the temporary support to which the liquid crystal composition is applied. The alignment layer has a rubbing treatment of organic compounds such as polymers (resins such as polyimide, polyvinyl alcohol, polyester, polyarylate, polyamideimide, polyetherimide, polyamide, and modified polyamide), oblique deposition of inorganic compounds, and microgrooves. It can be provided by means such as formation of a layer or accumulation of an organic compound (for example, ω-tricosanoic acid, dioctadecylmethylammonium chloride, methyl stearylate) by the Langmuir-Blodgett method (LB film). An alignment layer that generates an alignment function by application of an electric field, application of a magnetic field, or light irradiation may be used.

In particular, the alignment layer made of a polymer is preferably subjected to a rubbing treatment and then a liquid crystal composition is applied to the rubbing treatment surface. The rubbing treatment can be performed by rubbing the surface of the polymer layer several times in a certain direction with paper or cloth.
The liquid crystal composition may be applied to the surface of the temporary support without providing the alignment layer, or the surface obtained by rubbing the temporary support.
When the temporary support is peeled off, the alignment film does not have to be peeled off together with the temporary support to form a layer constituting the reflector of the present invention, and is peeled off at the interface between the temporary support and the alignment film. The film may be a layer constituting the reflective material of the present invention.
The thickness of the alignment layer is preferably 0.01 to 5 μm, and more preferably 0.05 to 2 μm.

[Unevenness flattening layer]
The concavo-convex planarization layer is a layer provided so that one surface thereof is an concavo-convex surface and the other is a flat surface and is in direct contact with the concavo-convex surface of the circularly polarized light reflecting layer. The reflecting material of the present invention having an uneven planarizing layer has both surfaces flat. The uneven planarizing layer of the reflective material of the present invention preferably has an uneven surface complementary to the uneven shape of the surface on the uneven planarizing layer side of the circularly polarized light reflecting layer.
It is preferable that the unevenness flattening layer has a small refractive index difference from the circularly polarized light reflecting layer. This is because haze is less likely to occur when the refractive index difference is small. The difference in refractive index is preferably 0.1 or less, more preferably 0.05 or less, and further preferably 0.02 or less.
Moreover, it is preferable that an uneven | corrugated planarization layer is transparent. Further, the uneven planarizing layer is preferably low birefringence. In particular, when the circularly polarized light reflection layer includes only one of a cholesteric liquid crystal layer having a spiral sense on the right or a cholesteric liquid crystal layer having a spiral sense on the left, the uneven flattening layer may have low birefringence. preferable.

The uneven flattening layer is not particularly limited as long as it has the above-mentioned shape, but examples include a substrate used as a substrate having an uneven surface when forming the uneven shape of the circularly polarized light reflecting layer, and the uneven shape of the circularly polarized light reflecting layer. Examples include a combination of an overcoat layer, a plastic film, an inorganic glass plate, or the like applied to the uneven surface of the circularly polarized light reflecting layer and an adhesive layer or an adhesive layer after the formation.
The average value of the unevenness flattening layer may be about 5 μm to 1000 μm, preferably 10 μm to 250 μm, and more preferably 15 μm to 150 μm.

(Base material)
The substrate preferably has an uneven surface complementary to the uneven shape of the surface on the uneven flattening layer side of the circularly polarized light reflecting layer, and the other surface of the substrate is preferably a flat surface.
Examples of the substrate include a microlens film, a prism film, and a lenticular sheet. As a microlens film, for example, ML1 or ML4 manufactured by Korea SKC Haas Display Films Co. Ltd., and as a prism film, for example, HD74U manufactured by Korea SKC Haas Display Films Co. Ltd., SPX2 manufactured by Suntech Opto Corporation, As SPX3, SPX6, and lenticular sheet, for example, LS-200Y manufactured by FUJIFILM (China) Investment Co., Ltd. can be used. The material of the substrate is preferably plastic, and examples thereof include polyester such as polyethylene terephthalate (PET), polycarbonate, acrylic resin, epoxy resin, polyurethane, polyamide, polyolefin, cellulose derivative, and silicone.

These base materials may be used as they are, or may be used by adjusting the concave / convex shape to a desired shape by filling a part of the concave portion of the concave / convex surface. In such a case, the uneven shape may be adjusted to a desired shape by heating. As a method for filling a part of the concave portion of the concave and convex surface, for example, application of resin or vapor deposition of a metal material can be applied, but is not limited thereto.
When peeling the said base material from a liquid crystal composition after bonding, the uneven | corrugated surface of the said base material may release-process previously. As a release treatment method, for example, a method of laminating a fluorine-based polymer or a silicone resin on an uneven surface by coating or plasma treatment can be applied, but the method is not limited thereto.

(Overcoat layer)
Examples of the overcoat layer include a layer provided by applying a composition containing an ultraviolet curable monomer to the surface of the circularly polarized light reflection layer and then curing it.

  Examples of UV curable monomers include esters of polyhydric alcohols and (meth) acrylic acid (eg, ethylene glycol di (meth) acrylate, 1,4-dichlorohexane diacrylate, pentaerythritol tetra (meth) acrylate), penta Erythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, pentaerythritol hexa (meth) acrylate 1,2,3-cyclohexanetetramethacrylate, polyurethane polyacrylate, polyester polyacrylate), vinylbenzene and its derivatives (eg, 1,4-divinylbenzene). Zen, 4-vinylbenzoic acid-2-acryloyl ethyl ester, 1,4-divinylcyclohexanone), vinyl sulfone (eg, divinyl sulfone), acrylamide (eg, methylenebisacrylamide) and methacrylamide, epoxy monomer (diethylene glycol diglycidyl ether) Hexanediol diglycidyl ether, dimethylolpropane diglycidyl ether, polypropylene glycol diglycidyl ether, trimethylolpropane triglycidyl ether, and pentaerythritol tetraglycidyl ether). The ultraviolet curable monomer may be a mixture of two or more.

(Adhesive layer or combination of adhesive layer and plastic film)
The uneven flattening layer can also be formed by sticking a plastic film to the surface of the circularly polarized light reflecting layer with an adhesive or an adhesive. Even if both sides are flat surfaces, the plastic film may have irregularities as exemplified as the base material.
Examples of the plastic film include polyester such as polyethylene terephthalate (PET), polycarbonate, acrylic resin, epoxy resin, polyurethane, polyamide, polyolefin, cellulose derivative, and silicone.
The pressure-sensitive adhesive or adhesive is not particularly limited, but the pressure-sensitive adhesive is acrylic, silicone, urethane, and the adhesive is natural rubber, starch, acrylic, urethane, vinyl acetate, chloride. A vinyl type, a silicone type, an epoxy type, an isocyanate type, etc. are mentioned. Two or more kinds of pressure-sensitive adhesives, or two or more kinds of adhesives may be mixed and used, or a pressure-sensitive adhesive pressure-sensitive adhesive and an adhesive may be mixed and used. As the adhesive layer (adhesive), an adhesive layer similar to the adhesive layer for adhering each layer of the optical member described later may be used.

[Support]
The support is preferably transparent in the visible light region and has a small refractive index difference from the circularly polarized reflective layer. The difference in refractive index is preferably 0.1 or less, more preferably 0.05 or less, and further preferably 0.02 or less. Further, when the circularly polarized light reflection layer includes only one of a cholesteric liquid crystal layer having a spiral sense on the right and a cholesteric liquid crystal layer having a spiral sense on the left, the support preferably has low birefringence.
Examples of the transparent and low birefringent base material in the visible light region include inorganic glass and polymer resin.
Specific examples of polymer resin materials include acrylic resins (acrylic esters such as polymethyl (meth) acrylate), polycarbonate, cyclic polyolefins such as cyclopentadiene polyolefin and norbornene polyolefin, polyolefins such as polypropylene, polystyrene, etc. And aromatic vinyl polymers, polyarylate, and cellulose acylate.
The thickness of the support may be about 5 μm to 1000 μm, preferably 10 μm to 250 μm, and more preferably 15 μm to 90 μm.

<Optical member>
The reflective material of the present invention can be used as a constituent member of an optical member.
The optical member further includes an information presentation layer. The optical member may be in the form of a film or a sheet.
As the layer configuration of the optical member, a configuration in which the information presentation layer, the elastic organic layer, and the circularly polarized reflective layer are arranged in this order, or a configuration in which the information presentation layer, the circularly polarized reflective layer, and the elastic organic layer are arranged in this order is preferable. .

[Information presentation layer]
The information presentation layer has a pattern of a material that absorbs or reflects light having the reflection wavelength. That is, the information presentation layer has a pattern of a material that absorbs or reflects infrared rays. The pattern may be in the entire information presentation layer or in part. The material that absorbs or reflects the light having the reflection wavelength may be applied and printed on the surface of the reflective material by, for example, an ink jet method to form a pattern. Alternatively, for example, after being uniformly applied to the substrate surface, the pattern may be formed by printing and evaporation in units of 0.5 to 3000 μm using an infrared laser or the like. Regarding the latter method, for example, the description of JP-A-2011-152652 can be referred to.

  The pattern may be a pattern that can give at least the position or coordinate information of the selected partial region in the information presentation layer when the partial region is selected. The part to be selected may be a unit that can be photographed by a pen-type imaging device having, for example, a light source that emits infrared rays and a sensor that senses infrared rays. Examples of the pattern include a dot pattern described in paragraphs 0123 to 0152 of JP 2014-98943 A.

(Material that absorbs or reflects infrared rays)
Examples of materials that absorb or reflect infrared rays include carbon inks, inks containing inorganic ions (copper, iron, ytterbium and other metals), phthalocyanine dyes, dioctyl compound dyes, squalium dyes, croconium dyes, nickel complex dyes, etc. Other known organic dyes, other known infrared absorbing dyes, known infrared reflective particles, and the like can be used. The material that absorbs or reflects infrared rays preferably has no reflection or absorption in the visible wavelength region.

(Adhesive layer)
The optical member of the present invention may include an adhesive layer for bonding the layers. The reflective material of the present invention may include an adhesive layer. The adhesive layer may be formed from an adhesive.

  Adhesives include hot melt type, thermosetting type, photocuring type, reactive curing type, and pressure-sensitive adhesive type that does not require curing, from the viewpoint of curing method, and the materials are acrylate, urethane, urethane acrylate, epoxy , Epoxy acrylate, polyolefin, modified olefin, polypropylene, ethylene vinyl alcohol, vinyl chloride, chloroprene rubber, cyanoacrylate, polyamide, polyimide, polystyrene, polyvinyl butyral, etc. can do. From the viewpoint of workability and productivity, the photocuring type is preferable as the curing method, and from the viewpoint of optical transparency and heat resistance, it is preferable to use an acrylate, urethane acrylate, epoxy acrylate, or the like material.

[Use of optical members]
Although it does not specifically limit as an application of the optical member of this invention, For example, it can use as a handwritten input sheet used with the system using the optical pen which digitizes handwritten information and inputs into information processing apparatus. In use, the composition of the cholesteric liquid crystal layer is adjusted so that the wavelength of infrared rays emitted from the optical pen is the wavelength at which the reflective material shows reflection. Specifically, the spiral pitch of the cholesteric liquid crystal phase may be adjusted by the above method. When the optical member is used as a handwritten input sheet, it is sufficient that light is irradiated from the information presentation layer side of the optical member and reflected light is detected from the information presentation layer side of the optical member.

  The optical member of the present invention is disposed, for example, on the display surface or in front of the image display device, and can be used as a handwriting input sheet. In FIG. 6, the optical member 12 including the reflecting material 11 and the information presentation layer 5 disposed in front of the display 6 is shown. Light 21 irradiated with light from the information presentation layer 5 side having the dot pattern 13 and reflected by the reflector 11 can be detected.

  The optical member may be bonded directly to the display surface or via another film or the like, and may be integrated with the display. For example, the optical member may be detachably attached to the display surface. When integrated, the optical member of the present invention may be disposed between the forefront of the image display device or the protective front plate and the display panel. The optical member of the present invention is preferably arranged so that the reflective material and the information presentation layer side are in this order from the display surface side. It is preferable that the display does not emit infrared light in the reflection wavelength region of the reflective material in the optical member so that there is no false detection with the image sensor of the optical pen.

  Regarding a handwriting input system that digitizes handwritten information and inputs it to an information processing apparatus or an image display device that is equipped with a handwriting input sheet, JP2014-67398A, JP2014-98943A, JP2008-165385A. [0021] to [0032] of Japanese Patent Laid-Open No. 2008-108236, Japanese Patent Laid-Open No. 2008-077451, or Japanese Patent No. 4725417.

  The present invention will be described more specifically with reference to the following examples. The materials, reagents, amounts and ratios of substances, operations, and the like shown in the following examples can be appropriately changed without departing from the gist of the present invention. Therefore, the scope of the present invention is not limited to the following examples.

<Production of reflective material>
[Production of Laminate 1]
A rubbing treatment is performed on the surface of PET film (Toyobo Co., Ltd. Cosmo Shine A-4100: thickness 75 μm) which has not been subjected to an easy adhesion treatment, and coating liquid A-1 or A-2 shown in Table 1 is applied to the rubbing treatment surface. The film was applied at room temperature so that the dry film thickness after drying was 4 μm. After the coating layer is dried at room temperature for 1 minute, it is heated in an atmosphere at 85 ° C. for 2 minutes, and then at 30 ° C. with a fusion D bulb (lamp 90 mW / cm) so that the UV irradiation amount shown in Table 2 is obtained. The UV output and the irradiation time were adjusted to perform UV irradiation to form a cholesteric liquid crystal layer or a semi-cured cholesteric liquid crystal layer to obtain a laminate 1.

[Production of Laminate 2]
On acrylic film (Technoloy S001G manufactured by Escarbo Sheet Co., Ltd.), coating liquid B, coating liquid C, and UVP-3000 (Toagosei) or Mizuame (Nippon Starch Industries) shown in Table 1 are dried according to Table 2. Was applied at room temperature so as to be 20 μm. The coating layer is dried at room temperature for 1 minute, then heated in an atmosphere of 85 ° C. for 2 minutes, and then at 30 ° C. with a fusion D bulb (lamp 90 mW / cm) so that the UV irradiation amount becomes 10 mJ / cm ^2. The UV output and the irradiation time were adjusted to perform UV irradiation, and an elastic organic layer was formed to obtain a laminate 2.

[Production of Laminate 10]
Using the laminator (Hartex Bio330), the cholesteric liquid crystal layer or semi-cured cholesteric liquid crystal layer and the elastic organic layer prepared above are arranged so as to face each other, and the laminate 1 and laminate 2 are arranged. After the lamination, the PET film was peeled off to obtain a laminate 10 having a cholesteric liquid crystal layer or semi-cured cholesteric liquid crystal layer, an elastic organic layer, and a support in this order.

[Fabrication of reflective material: formation of irregular shape]
As shown in Table 2, a concavo-convex shape was formed by any of the following methods 1 to 4, and a reflective material was produced.
(Method 1)
It arrange | positions so that the uneven | corrugated surface of the base material shown to a table | surface and a cholesteric liquid crystal layer or a semi-hardened cholesteric liquid crystal layer may face each other with respect to the laminated body 10 obtained by the above, and it is in Crime Products company vacuum bonding machine V-SE6055aa. , Temperature 60 ° C., pressure 0.3 MPa, pressurization time 5 min. It pastes on the conditions of and obtains a reflecting material.

(Method 2)
With respect to the reflective material obtained in Method 1, the UV output and irradiation time are adjusted at 30 ° C. with a fusion D bulb (lamp 90 mW / cm) so that the UV irradiation amount is 300 mJ / cm ^2, and UV irradiation is performed. Get a reflector.

(Method 3)
The coating liquid C was applied to the surface of the cholesteric liquid crystal layer or semi-cured cholesteric liquid crystal layer of the laminate 10 at room temperature so as to have a dry film thickness of 1 μm. Then, it heats for 2 minutes in 85 degreeC atmosphere, arrange | positions so that the uneven | corrugated surface of a base material shown to a table | surface and a cholesteric liquid crystal layer or a semi-hardened cholesteric liquid crystal layer may face each other, and vacuum bonding is performed by the same method as the method 1. The obtained sample is subjected to UV irradiation at 30 ° C. with a fusion D bulb (lamp 90 mW / cm) to adjust the UV output and irradiation time so that the UV irradiation amount is 300 mJ / cm ^2. obtain.

(Method 4)
The base material is peeled off from the reflective material obtained by the method 1, and the coating solution D is applied to the peeled surface at room temperature so as to have a dry film thickness of 20 μm. Thereafter, heating is performed in an atmosphere of 85 ° C. for 2 minutes, and then UV output and irradiation time are adjusted at 30 ° C. using a fusion D bulb (lamp 90 mW / cm) so that the UV irradiation amount becomes 300 mJ / cm ^2. Irradiate to obtain a reflector.

<Evaluation of reflective material>
The obtained reflecting material was evaluated as follows. The results are shown in Table 2.
(Storage modulus)
In the state of the laminate 2, using a dynamic viscoelasticity measuring device NDS-1000 manufactured by Taisei Co., Ltd. under a shear mode, a frequency of 1 Hz, and a measurement rate of 5 ° C./minute, within a temperature range of −20 to 100 ° C. The storage modulus was measured.
(Haze value)
The haze value was measured using a haze meter NDH-2000 manufactured by Nippon Denshoku Industries Co., Ltd. In the measurement, the measurement was performed so that incident light was applied from the side of the acrylic film as the support.

(45 degree relative retroreflectivity)
Measurement was performed using an ultraviolet-visible near-infrared spectrophotometer V-670 (manufactured by JASCO Corporation) in combination with an absolute reflectance measurement unit ARV474S (manufactured by JASCO Corporation). As shown in FIG. 4, incident light is applied from a position inclined 45 degrees with respect to the normal direction of the sample 101 surface, and a signal at a position 8 degrees from the position (53 degrees with respect to the normal direction of the sample surface) is obtained. This was detected and used as the retroreflective signal intensity. In FIG. 4, a detector 103 is an InGaAs detector in the ultraviolet-visible near-infrared spectrophotometer V-670, and can detect near-infrared light. Incident light was adjusted to a wavelength of 850 nm, and in the measurement, the incident light was applied from the acrylic film side as a support.

The retroreflective signal intensity when a standard diffuser (manufactured by Labsphere) is installed at the sample position is 100%, and the ratio of the retroreflective intensity when each of the reflection films prepared above is installed at the sample position is a relative recursion. The reflectance was calculated by the following formula.

(Relative retroreflectivity) = (Retroreflective signal strength of reflector) / (Retroreflected signal strength of standard diffuser) x 100
Moreover, about Examples 1-3 using a lenticular, it measured from the perpendicular | vertical direction with respect to the uneven | corrugated shaped ridgeline direction.

  FIG. 5 shows a photograph of the cross section of the reflective material of Example 1 taken with a scanning electron microscope (SEM) (ultra high resolution field emission scanning electron microscope S-5500 manufactured by Hitachi High-Technologies Corporation). The circularly polarized light reflection layer is a portion where the pitch in the cholesteric liquid crystal layer is observed in a laminated form. It can be seen that the circularly polarized light reflection layer has an uneven shape, one surface of the elastic organic layer has an uneven surface complementary to the shape, and the other surface is flat. Similarly, the SEM imaging was performed for the reflective materials of Examples 2 to 8, and the circularly polarized reflective layer showed an uneven shape, and the one-side surface of the elastic organic layer was complementary to the shape, similarly to the reflective material of Example 1. As a result, it was confirmed that the other surface was flat.

<Production of optical member: formation of information presentation layer>
Carbon ink was applied to the flat side of the uneven flattening layer of the reflective material prepared above. The coated surface was irradiated with infrared light having a YVO ₄ laser (wavelength: 1064 nm) beam diameter of 10 μm, and a predesigned dot pattern was formed by printing evaporation. That is, the carbon ink was removed according to the designed dot pattern.

DESCRIPTION OF SYMBOLS 1 Circularly polarized light reflection layer 2 Elastic organic layer 3 Concavity and convexity flattening layer 4 Support body 5 Information presentation layer 6 Display 11 Reflector 12 Optical member 13 Dot pattern 21 Light 101 Sample 102 Mirror 103 Detector

Claims (19)

An optical member including a reflective material and an information presentation layer,
The reflector includes a circularly polarized reflective layer and an elastic organic layer;
The circularly polarized light reflection layer includes a layer in which a cholesteric liquid crystal phase is fixed,
The circularly polarized light reflection layer has an uneven shape,
The elastic organic layer has one surface directly in contact with the circularly polarized light reflecting layer, and the other surface is a flat surface,
The circularly polarized light reflecting layer alternately has a slope 1 and a slope 2 whose directions are opposite to each other in one of the in-plane directions of the circularly polarized light reflecting layer, and the slope 1 is 1 μm or more and 500 μm or less. The maximum value of the angle formed by the inclination 1 and the flat surface is 10 degrees or more and 60 degrees or less, and the maximum value of the angle formed by the inclination 2 and the flat surface is 10 degrees or more and 60 degrees or less. Yes,
The surface of the elastic organic layer that is in direct contact with the circularly polarized reflective layer has a concavo-convex shape complementary to the surface of the circularly polarized reflective layer on the elastic organic layer side,
The reflective material further includes an uneven planarization layer;
The uneven flattening layer, the circularly polarized light reflecting layer and the elastic organic layer are in this order,
The uneven planarizing layer is in direct contact with the uneven surface of the circularly polarized light reflecting layer;
The information presentation layer has a pattern of a material that absorbs or reflects light reflected by the reflective material,
The optical member , wherein the reflective material reflects light in an infrared wavelength region . The optical member according to claim 1 , wherein the uneven flattening layer is a microlens film. The optical member according to claim 1 , wherein the uneven flattening layer is a prism film or a lenticular sheet. The optical member as described in any one of Claims 1-3 which contains a support body in the flat surface side of the said elastic organic layer. The optical member according to claim 1, wherein the elastic organic layer is an ultraviolet curable adhesive layer. The optical member according to claim 1 , having a haze value of 50% or less. The optical member according to claim 1 , wherein the pattern is a dot pattern. The optical member according to any one of claims 1 to 7, wherein the pattern is formed by printing. A display comprising the optical member according to claim 1 . An image display apparatus comprising the display according to claim 9 . It is a manufacturing method of the optical member according to any one of claims 1 to 8 ,
Preparing a laminate 10 comprising an elastic organic layer and a cholesteric liquid crystal layer;
The uneven surface of the substrate having an uneven surface is bonded to the surface of the laminate 10 on the cholesteric liquid crystal layer side to form the uneven surface on the elastic organic layer, and at the same time, the uneven surface of the substrate and the elastic organic layer Including making the cholesteric liquid crystal layer concavo-convex between the concavo-convex surface of
The manufacturing method in which the cholesteric liquid crystal layer of the laminate 10 is a layer obtained by curing or semi-curing a liquid crystal composition containing a polymerizable liquid crystal compound. The manufacturing method according to claim 11 , wherein the bonding is vacuum bonding. The manufacturing method of Claim 11 or 12 with which the said bonding is performed at 40 to 110 degreeC. Wherein a layer cholesteric liquid crystal layer was semi-cured liquid crystal composition containing the polymerizable liquid crystal compound, and after formation of the irregularities, claims 11 to 13 comprising heating or light irradiation laminate 10 The manufacturing method as described in any one of these . The manufacturing method according to claim 14 , wherein the light is ultraviolet light, and the light irradiation is performed at 100 mJ / cm ² or more. The manufacturing method as described in any one of Claims 11-15 including apply | coating an elastic organic layer forming material to the surface of the said cholesteric liquid crystal layer, and forming the said elastic organic layer. The laminate 10 includes a support, the elastic organic layer, and the cholesteric liquid crystal layer,
The preparation of the laminate 10 is such that the laminate 1 including the temporary support and the cholesteric liquid crystal layer and the laminate 2 including the support and the elastic organic layer are brought into contact with the cholesteric liquid crystal layer and the elastic organic layer surface. The manufacturing method as described in any one of Claims 11-15 performed by the method including laminating | stacking on the said and peeling the said temporary support body after the said lamination | stacking. The manufacturing method according to claim 17 , wherein the elastic modulus of the elastic organic layer of the laminate 2 is 10 ³ to 10 ⁶ Pa at 30 ° C. Coating the liquid crystal composition containing the polymerizable liquid crystal compound on the surface of the temporary support, and forming the cholesteric liquid crystal layer by irradiating the liquid crystal composition with ultraviolet rays of 50 mJ / cm ² or less. The manufacturing method according to claim 17 or 18 .