JP2022027908A - Retardation plate, polarizing plate with optical compensation layer, image display device, and image display device with touch panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a retardation plate which allows for producing an image display device that exhibits neutral hue in oblique directions.

SOLUTION: A retardation plate of the present invention has: an in-plane retardation Re that satisfies 100 nm≤Re(550)≤160 nm, Re(450)/Re(550)≤1, and Re(650)/Re(550)≥1; and Nz coefficient that satisfies Nz(550)<1, 0≤|Nz(450)-Nz(550)|≤0.1, and 0≤|Nz(650)-Nz(550)|≤0.1.

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2022,JPO&INPIT

Description

The present invention relates to a retardation plate, a polarizing plate with an optical compensation layer, an image display device, and an image display device with a touch panel.

In recent years, with the spread of thin displays, an image display device (organic EL display device) equipped with an organic EL panel has been proposed. The organic EL panel has a highly reflective metal layer, and tends to cause problems such as external light reflection and background reflection. Therefore, it is known to prevent these problems by providing a polarizing plate with an optical compensation layer (circular polarizing plate) on the visual recognition side. Further, it is known that the viewing angle is improved by providing a polarizing plate with an optical compensation layer on the visual recognition side of the liquid crystal display panel. As a general polarizing plate with an optical compensation layer, a retardation film and a polarizing element are laminated so that their slow-phase axis and absorption axis form a predetermined angle (for example, 45 °) according to the application. Are known. However, the conventional retardation film has a problem that when it is used as a polarizing plate with an optical compensation layer, undesired coloring may occur in the hue in the oblique direction.

Japanese Unexamined Patent Publication No. 2016-42185

The present invention has been made to solve the above-mentioned conventional problems, and its main purpose is a retardation plate capable of realizing an image display device having a neutral hue in an oblique direction, and such a retardation plate. It is an object of the present invention to provide a polarizing plate with an optical compensation layer, an image display device, and a touch panel device.

In the retardation plate of the present invention, the in-plane retardation Re is 100 nm ≤ Re (550) ≤ 160 nm, Re (450) / Re (550) ≤ 1, and Re (650) / Re (550) ≥ 1. Satisfied and the Nz coefficient is Nz (550) <1, 0 ≦ | Nz (450) -Nz (550) | ≦ 0.1, and 0 ≦ | Nz (650) -Nz (550) | ≦ 0.1 Meet.
In one embodiment, the first retardation layer has a laminated structure in which a first retardation layer and a second retardation layer are laminated, and the first retardation layer has an in-plane retardation Re of Re (450). ) / Re (550) ≦ 1 and Re (650) / Re (550) ≧ 1, the refractive index characteristic satisfies nx> ny ≧ nz, and the second retardation layer has a thickness direction retardation. Rth satisfies Rth (450) / Rth (550) ≦ 1 and Rth (650) / Rth (550) ≧ 1, and the refractive index characteristic satisfies nz> nx ≧ ny.
According to another aspect of the present invention, a polarizing plate with an optical compensation layer is provided. The polarizing plate with an optical compensation layer has an optical compensation layer composed of the retardation plate and a polarizing element, and the angle formed by the slow axis of the optical compensation layer and the absorption axis of the polarizing element is 35. ° to 55 °.
In one embodiment, the polarizing plate with an optical compensation layer has a conductive layer on the opposite side of the optical compensation layer from the polarizing element.
According to yet another aspect of the present invention, an image display device is provided. This image display device has the above-mentioned polarizing plate with an optical compensation layer.
According to yet another aspect of the present invention, an image display device with a touch panel is provided. This image display device with a touch panel has the polarizing plate with the optical compensation layer, and the conductive layer functions as a touch panel sensor.

According to the present invention, the in-plane retardation Re of the retardation plate is 100 nm ≦ Re (550) ≦ 160 nm, Re (450) / Re (550) ≦ 1, and Re (650) / Re (550) ≧. 1 is satisfied, and the Nz coefficient is Nz (550) <1, 0 ≦ | Nz (450) -Nz (550) | ≦ 0.1, and 0 ≦ | Nz (650) -Nz (550) | ≦ 0. By satisfying 1. 1, a polarizing plate with an optical compensation layer having a neutral hue in the diagonal direction when used for a polarizing plate with an optical compensation layer can be realized.

It is the schematic sectional drawing of the retardation plate by one Embodiment of this invention. It is the schematic sectional drawing of the polarizing plate with an optical compensation layer by one Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to these embodiments.

(Definition of terms and symbols)
Definitions of terms and symbols herein are as follows.
(1) Refractive index (nx, ny, nz)
"Nx" is the refractive index in the direction in which the refractive index in the plane is maximized (that is, the direction of the slow phase axis), and "ny" is the direction orthogonal to the slow phase axis in the plane (that is, the direction of the phase advance axis). Is the refractive index of, and "nz" is the refractive index in the thickness direction.
(2) In-plane phase difference (Re)
“Re (λ)” is an in-plane phase difference measured with light having a wavelength of λ nm at 23 ° C. For example, "Re (550)" is an in-plane phase difference measured with light having a wavelength of 550 nm at 23 ° C. Re (λ) is obtained by the formula: Re = (nx−ny) × d, where d (nm) is the thickness of the layer (film).
(3) Phase difference in the thickness direction (Rth)
“Rth (λ)” is a phase difference in the thickness direction measured with light having a wavelength of λ nm at 23 ° C. For example, "Rth (550)" is a phase difference in the thickness direction measured with light having a wavelength of 550 nm at 23 ° C. Rth (λ) is obtained by the formula: Rth = (nx-nz) × d, where d (nm) is the thickness of the layer (film).
(4) Nz coefficient The Nz coefficient is obtained by Nz = Rth / Re.

A. Phase difference plate In the phase difference plate 10 of the present invention, the in-plane retardation Re is 100 nm ≤ Re (550) ≤ 160 nm, Re (450) / Re (550) ≤ 1, and Re (650) / Re (550). ) ≧ 1, and the Nz coefficient is Nz (550) <1, 0 ≦ | Nz (450) -Nz (550) | ≦ 0.1, and 0 ≦ | Nz (650) -Nz (550) | Satisfy ≤0.1. That is, the retardation plate exhibits a reverse dispersion wavelength characteristic in which the retardation value increases according to the wavelength of the measurement light, the wavelength dependence of the Nz coefficient is small, and the refractive index with respect to the measurement light in a wide wavelength range. The characteristic shows the relationship of nx>nz> ny. As a result, the retardation plate can realize a polarizing plate with an optical compensation layer in which the hue in the diagonal direction is neutral when used as a polarizing plate with an optical compensation layer. The retardation plate may have a single-wafer shape or a long shape.

FIG. 1 is a schematic cross-sectional view of a retardation plate 10 according to one embodiment of the present invention. Typically, the retardation plate 10 has a laminated structure in which the first retardation layer 11 and the second retardation layer 12 are laminated. In this case, in the first retardation layer 11, the in-plane retardation Re satisfies Re (450) / Re (550) ≦ 1 and Re (650) / Re (550) ≧ 1, and has a refractive index characteristic. Satisfies nx> ny ≧ nz, and the thickness direction retardation Rth of the second retardation layer 12 is Rth (450) / Rth (550) ≦ 1 and Rth (650) / Rth (550) ≧ 1. , And the refractive index characteristic satisfies nz> nx ≧ ny.

The in-plane retardation Re (550) of the retardation plate is preferably 120 nm to 150 nm, more preferably 130 nm to 145 nm. If the in-plane phase difference of the retardation plate is within the above range, the angle between the retardation plate and the splitter and the slow axis direction of the retardation plate and the absorption axis direction of the polarizing plate is about 45 ° or The polarizing plate with an optical compensation layer obtained by laminating so as to be about 135 ° can be used as a circular polarizing plate capable of realizing excellent antireflection characteristics.

With respect to the in-plane phase difference of the retardation plate, the value of Re (450) / Re (550) is preferably 0.80 to 0.90, more preferably 0.80 to 0.88, and even more preferably. Is 0.80 to 0.86. The values of Re (650) / Re (550) are preferably 1.01 to 1.20, more preferably 1.02 to 1.15, and even more preferably 1.03 to 1.10. .. Thereby, the retardation plate can achieve a better reflected hue.

As described above, the Nz coefficients of the retardation plate are Nz (550) <1, 0 ≦ | Nz (450) -Nz (550) | ≦ 0.1, and 0 ≦ | Nz (650) -Nz (550). ) | ≤ 0.1 is satisfied. Nz (550) is preferably 0.3 to 0.7, more preferably 0.4 to 0.6, still more preferably 0.45 to 0.55, and particularly preferably about 0. It is 5. When the Nz coefficient is in such a range, the refractive index characteristic shows the relationship of nx> nz> ny with respect to the measured light in a wide wavelength range, whereby the hue in the diagonal direction is neutral and excellent. A polarizing plate with an optical compensation layer having a wide viewing angle characteristic can be realized.

A-1. First phase difference layer As described above, in the first phase difference layer, the in-plane phase difference Re is Re (450) / Re (550) ≦ 1 and Re (650) / Re (550) ≧ 1. , And the refractive index characteristic satisfies nx> ny ≧ nz. The in-plane retardation Re (550) of the first retardation layer is preferably 100 nm to 170 nm, more preferably 110 nm to 160 nm, and even more preferably 120 nm to 150 nm.

With respect to the in-plane retardation of the first retardation layer, the value of Re (450) / Re (550) is preferably 0.80 to 0.90, more preferably 0.80 to 0.88. , More preferably 0.80 to 0.86. The values of Re (650) / Re (550) are preferably 1.01 to 1.20, more preferably 1.02 to 1.15, and even more preferably 1.03 to 1.10. ..

The first retardation layer is typically a retardation film made of any suitable resin capable of achieving the above characteristics. The retardation film can be obtained by stretching any suitable resin film capable of realizing the above characteristics under any suitable stretching conditions. Any suitable stretching method and stretching conditions (for example, stretching temperature, stretching ratio, stretching direction) can be adopted for the stretching. By appropriately selecting the stretching method and stretching conditions, a stretched film having the desired optical characteristics (for example, refractive index characteristics, in-plane retardation, Nz coefficient) can be obtained.

The photoelastic coefficient (absolute value) of the retardation film is preferably 14 × ^10-12 Pa ^-1 or less. The photoelastic coefficient of the retardation film is preferably 1 × 10 ^-12 Pa ^-1 to 14 × 10 ^-12 Pa ^-1 , and more preferably 2 × 10 ^-12 Pa ^-1 to 12 × 10 ^-12 Pa ⁻ . It is ¹ . When the absolute value of the photoelastic coefficient is in such a range, the change in the phase difference value can be suppressed even in a high temperature and high humidity environment, and excellent reliability can be realized. Further, it is possible to maintain the flexibility of the image display device (particularly, the organic EL panel) while ensuring a sufficient phase difference even with a small thickness, and further, the phase difference change due to the stress at the time of bending (as a result, the organic EL panel). Color change) can be further suppressed.

The water absorption rate of the retardation film is preferably 3% or less, more preferably 2.5% or less, still more preferably 2% or less. By satisfying such a water absorption rate, it is possible to suppress changes in display characteristics over time. The water absorption rate can be obtained in accordance with JIS K 7209.

The retardation film preferably has a barrier property against moisture and gas (eg oxygen). The water vapor permeability (moisture permeability) of the stretched film under the conditions of 40 ° C. and 90% RH is preferably less than 1.0 × 10 ^-1 g / m ^2/24 hr. From the viewpoint of barrier property, it is preferable that the lower limit of the moisture permeability is lower. The gas barrier property of the stretched film under 60 ° C. and 90% RH conditions is preferably 1.0 × ^10-7 g / m ^2/24 hr to 0.5 g / m ^2/24 hr, and more preferably 1.0. × ^10-7 g / m ^2/24 hr to 0.1 g / m ^2/24 hr. When the moisture permeability and the gas barrier property are within such a range, the organic EL panel can be satisfactorily protected from moisture and oxygen in the air when the polarizing plate with an optical compensation layer is attached to the organic EL panel. Both the moisture permeability and the gas barrier property can be measured according to JIS K 7126-1.

Examples of the resin constituting the retardation film include polyarylate, polyimide, polyamide, polyester, polyvinyl alcohol, polyfumaric acid ester, norbornene resin, polycarbonate resin, cellulose resin, cyclic olefin resin and polyurethane. These resins may be used alone or in combination. A polycarbonate resin is preferable. Specific examples of the above resin are described as thermoplastic resins in, for example, Japanese Patent Application Laid-Open No. 2015-21428. The entire description of the publication is incorporated herein by reference.

The glass transition temperature of the polycarbonate resin is preferably 110 ° C. or higher and 180 ° C. or lower, more preferably 120 ° C. or higher and 165 ° C. or lower. If the glass transition temperature is excessively low, the heat resistance tends to deteriorate, dimensional changes may occur after film molding, and the image quality of the obtained organic EL panel may be deteriorated. If the glass transition temperature is excessively high, the molding stability during film molding may be deteriorated, and the transparency of the film may be impaired. The glass transition temperature is determined according to JIS K 7121 (1987).

Examples of the stretching method include lateral uniaxial stretching, free end uniaxial stretching, fixed end biaxial stretching, fixed end uniaxial stretching, and sequential biaxial stretching. It is preferably fixed-end uniaxial stretching. Specific examples of the fixed-end uniaxial stretching include a method of stretching the resin film in the width direction (lateral direction) while running the resin film in the longitudinal direction. The draw ratio is preferably 1.1 to 3.5 times. The stretching temperature is preferably Tg-30 ° C to Tg + 60 ° C, more preferably Tg-10 ° C to Tg + 50 ° C with respect to the glass transition temperature (Tg) of the resin film. As another stretching method, a method of continuously diagonally stretching a long resin film in a direction of a predetermined angle with respect to the longitudinal direction can be mentioned. Examples of the method of diagonal stretching include JP-A-50-83482, JP-A-2-113920, JP-A-3-182701, JP-A-2000-9912, and JP-A-2002-86554. Examples thereof include the methods described in JP-A-2002-22944.

The thickness of the retardation film (first retardation layer) is preferably 10 μm to 150 μm, more preferably 10 μm to 100 μm, and further preferably 10 μm to 70 μm. With such a thickness, the desired in-plane phase difference and Nz coefficient can be obtained.

A-2. Second phase difference layer As described above, in the second phase difference layer, the thickness direction retardation Rth is Rth (450) / Rth (550) ≦ 1 and Rth (650) / Rth (550) ≧ 1. , And the refractive index characteristic satisfies nz> nx ≧ ny. The retardation Rth (550) in the thickness direction of the second retardation layer is preferably −30 nm to −200 nm, more preferably −35 nm to −180 nm, and further preferably −40 nm to −160 nm.

With respect to the thickness direction retardation of the second retardation layer, the value of Rth (450) / Rth (550) is preferably 0.70 to 0.90, more preferably 0.72 to 0.88. , More preferably 0.74 to 0.86. The value of Rth (650) / Rth (550) is preferably 1.01 to 1.20, more preferably 1.02 to 1.15, and even more preferably 1.03 to 1.10. ..

The second retardation layer may be typically composed of an oriented solidified layer of a liquid crystal compound capable of realizing the above characteristics. As used herein, the term "aligned solidified layer" refers to a layer in which a liquid crystal compound is oriented in a predetermined direction within the layer and the oriented state is fixed. In one embodiment, the second retardation layer may preferably include a liquid crystal material immobilized in a homeotropic orientation. The liquid crystal material (liquid crystal compound) that can be homeotropically oriented may be a liquid crystal monomer or a liquid crystal polymer. Specific examples of the liquid crystal compound and the method for forming the retardation layer are described in, for example, Japanese Patent No. 5826759. The entire description of the publication is incorporated herein by reference. Further, as other specific examples, Japanese Patent No. 5401032, Japanese Patent Application Laid-Open No. 2015-20861, and Japanese Patent Application Laid-Open No. 2015-169875 are described, and the entire description of these publications is described in the present specification. It is used as a reference. The thickness of the second retardation layer is preferably 0.5 μm to 50 μm, more preferably 0.5 μm to 40 μm, and even more preferably 0.5 μm to 30 μm.

B. A polarizing plate with an optical compensation layer FIG. 2 is a schematic cross-sectional view of a polarizing plate with an optical compensation layer according to one embodiment of the present invention. The polarizing plate 100 with an optical compensation layer of the present embodiment includes a polarizing element 20 and an optical compensation layer 10A. The optical compensation layer 10A is made of the retardation plate according to the above item A. In one embodiment, the angle formed by the slow axis of the optical compensation layer and the absorption axis of the substituent is 35 ° to 55 °. Practically, as shown in the illustrated example, the protective layer 30 may be provided on the side opposite to the optical compensation layer 10A of the polarizing element 20. Further, the polarizing plate with an optical compensation layer may be provided with another protective layer (also referred to as an inner protective layer) between the polarizing element 20 and the optical compensation layer 10A. In the illustrated example, the inner protective layer is omitted. In this case, the optical compensation layer 10A can also function as an inner protective layer. With such a configuration, further reduction in thickness of the polarizing plate with an optical compensation layer can be realized. Further, if necessary, the conductive layer and the base material may be provided in this order on the opposite side of the optical compensation layer 10A from the polarizing element 20 (that is, the outside of the optical compensation layer 10A) (neither is shown). The base material is closely laminated to the conductive layer. As used herein, the term "adhesive lamination" means that two layers are directly and fixedly laminated without intervening an adhesive layer (for example, an adhesive layer and an adhesive layer). The conductive layer and the base material can be typically introduced into the polarizing plate 100 with an optical compensation layer as a laminate of the base material and the conductive layer. By further providing the conductive layer and the base material, the polarizing plate 100 with an optical compensation layer can be suitably used for an image display device with an inner touch panel.

B-1. Polarizer As the splitter 20, any suitable polarizing element may be adopted. For example, the resin film forming the polarizing element may be a single-layer resin film, or may be produced by using a laminated body having two or more layers.

Specific examples of the polarizing element composed of a single-layer resin film include a hydrophilic polymer film such as a polyvinyl alcohol (PVA) -based film, a partially formalized PVA-based film, and an ethylene / vinyl acetate copolymer-based partially saponified film. Examples thereof include those which have been dyed and stretched with a bicolor substance such as iodine and a bicolor dye, and polyene-based oriented films such as a dehydrated product of PVA and a dehydrogenated product of polyvinyl chloride. Preferably, since the PVA-based film is excellent in optical properties, a polarizing element obtained by dyeing a PVA-based film with iodine and uniaxially stretching it is used.

The dyeing with iodine is performed, for example, by immersing a PVA-based film in an aqueous iodine solution. The draw ratio of the uniaxial stretching is preferably 3 to 7 times. The stretching may be performed after the dyeing treatment or may be performed while dyeing. Further, it may be dyed after being stretched. If necessary, the PVA-based film is subjected to a swelling treatment, a crosslinking treatment, a cleaning treatment, a drying treatment and the like. For example, by immersing the PVA-based film in water and washing it with water before dyeing, it is possible not only to clean the dirt and blocking inhibitor on the surface of the PVA-based film, but also to swell the PVA-based film to prevent uneven dyeing. Can be prevented.

Specific examples of the polarizing element obtained by using the laminate include a laminate of a resin base material and a PVA-based resin layer (PVA-based resin film) laminated on the resin base material, or a resin base material and the resin. Examples thereof include a polarizing element obtained by using a laminate with a PVA-based resin layer coated and formed on a base material. The polarizing element obtained by using the laminate of the resin base material and the PVA-based resin layer coated and formed on the resin base material is, for example, a resin base material obtained by applying a PVA-based resin solution to the resin base material and drying it. It is produced by forming a PVA-based resin layer on the PVA-based resin layer to obtain a laminate of a resin base material and a PVA-based resin layer; and stretching and dyeing the laminate to make the PVA-based resin layer a stator. obtain. In the present embodiment, stretching typically includes immersing the laminate in an aqueous boric acid solution for stretching. Further, stretching may further comprise, if necessary, stretching the laminate in the air at a high temperature (eg, 95 ° C. or higher) prior to stretching in boric acid aqueous solution. The obtained resin base material / polarizing element laminate may be used as it is (that is, the resin base material may be used as a protective layer for the polarizing element), and the resin base material is peeled off from the resin base material / polarizing element laminate. Then, an arbitrary appropriate protective layer according to the purpose may be laminated on the peeled surface and used. Details of the method for producing such a polarizing element are described in, for example, Japanese Patent Application Laid-Open No. 2012-73580. The entire description of the publication is incorporated herein by reference.

The thickness of the splitter is preferably 25 μm or less, more preferably 1 μm to 12 μm, still more preferably 3 μm to 12 μm, and particularly preferably 3 μm to 8 μm. When the thickness of the splitter is in such a range, curling during heating can be satisfactorily suppressed, and good appearance durability during heating can be obtained.

The splitter preferably exhibits absorption dichroism at any wavelength of 380 nm to 780 nm. The simple substance transmittance of the polarizing element is 43.0% to 46.0%, preferably 44.5% to 46.0%, as described above. The degree of polarization of the polarizing element is preferably 97.0% or more, more preferably 99.0% or more, and further preferably 99.9% or more.

B-2. Protective layer The protective layer 30 is made of any suitable film that can be used as a protective layer for the stator. Specific examples of the material that is the main component of the film include cellulose-based resins such as triacetyl cellulose (TAC), polyester-based, polyvinyl alcohol-based, polycarbonate-based, polyamide-based, polyimide-based, polyethersulfone-based, and polysulfone-based. , Polyester-based, polycarbonate-based, polyolefin-based, (meth) acrylic-based, acetate-based transparent resins and the like. Further, thermosetting resins such as (meth) acrylic, urethane, (meth) acrylic urethane, epoxy, and silicone, or ultraviolet curable resins can also be mentioned. In addition to this, for example, glassy polymers such as siloxane-based polymers can also be mentioned. Further, the polymer film described in JP-A-2001-343529 (WO01 / 37007) can also be used. As the material of this film, for example, a resin composition containing a thermoplastic resin having a substituted or unsubstituted imide group in the side chain and a thermoplastic resin having a substituted or unsubstituted phenyl group and a nitrile group in the side chain. Can be used, and examples thereof include a resin composition having an alternating copolymer composed of isobutene and N-methylmaleimide and an acrylonitrile / styrene copolymer. The polymer film can be, for example, an extruded product of the above resin composition.

The protective layer 30 may be subjected to surface treatment such as hard coat treatment, antireflection treatment, sticking prevention treatment, and antiglare treatment, if necessary. Further / or, if necessary, the protective layer 30 is provided with a process for improving visibility when visually recognizing through polarized sunglasses (typically, a (elliptical) circular polarization function is provided, and an ultra-high phase difference is provided. May be given). By performing such processing, excellent visibility can be realized even when the display screen is visually recognized through a polarizing lens such as polarized sunglasses. Therefore, the polarizing plate with an optical compensation layer can be suitably applied to an image display device that can be used outdoors.

The thickness of the protective layer 30 is typically 5 mm or less, preferably 1 mm or less, more preferably 1 μm to 500 μm, and even more preferably 5 μm to 150 μm. When the surface treatment is applied, the thickness of the protective layer is the thickness including the thickness of the surface treatment layer.

When an inner protective layer is provided between the polarizing element 20 and the optical compensation layer 10A, it is preferable that the inner protective layer is optically isotropic. As used herein, "optically isotropic" means that the in-plane retardation Re (550) is 0 nm to 10 nm and the thickness direction retardation Rth (550) is -10 nm to +10 nm. say. The inner protective layer may be constructed of any suitable material as long as it is optically isotropic. The material may be appropriately selected from the materials described above with respect to the protective layer 30, for example.

The thickness of the inner protective layer is preferably 5 μm to 200 μm, more preferably 10 μm to 100 μm, and even more preferably 15 μm to 95 μm.

B-3. Conductive layer or conductive layer with substrate The conductive layer can be patterned as needed. By patterning, a conductive portion and an insulating portion can be formed. As a result, electrodes can be formed. The electrode can function as a touch sensor electrode that senses contact with the touch panel. The shape of the pattern is preferably a pattern that operates well as a touch panel (for example, a capacitive touch panel). Specific examples include the patterns described in JP-A-2011-511357, JP-A-2010-164938, JP-A-2008-310550, JP-A-2003-511799, and JP-A-2010-541109. Will be.

The conductive layer forms a metal oxide film on any suitable substrate by any suitable film forming method (for example, vacuum deposition method, sputtering method, CVD method, ion plating method, spray method, etc.). It can be formed as a film. After the film formation, heat treatment (for example, 100 ° C. to 200 ° C.) may be performed if necessary. The amorphous film can be crystallized by performing the heat treatment. Examples of the metal oxide include indium oxide, tin oxide, zinc oxide, indium-tin composite oxide, tin-antimon composite oxide, zinc-aluminum composite oxide, and indium-zinc composite oxide. The indium oxide may be doped with divalent metal ions or tetravalent metal ions. It is preferably an indium-based composite oxide, and more preferably an indium-tin composite oxide (ITO). The indium-based composite oxide has a high transmittance (for example, 80% or more) in the visible light region (380 nm to 780 nm), and has a feature that the surface resistance value per unit area is low.

When the conductive layer contains a metal oxide, the thickness of the conductive layer is preferably 50 nm or less, more preferably 35 nm or less. The lower limit of the thickness of the conductive layer is preferably 10 nm.

The surface resistance value of the conductive layer is preferably 300 Ω / □ or less, more preferably 150 Ω / □ or less, and further preferably 100 Ω / □ or less.

The conductive layer may be transferred from the base material to the optical compensation layer to form a constituent layer of a polarizing plate with an optical compensation layer by itself, and may be optically compensated as a laminate with the base material (conductive layer with a base material). It may be laminated in a layer. Typically, as described above, the conductive layer and the base material can be introduced into the polarizing plate with an optical compensation layer as the conductive layer with a base material.

Examples of the material constituting the base material include any suitable resin. A resin having excellent transparency is preferable. Specific examples include cyclic olefin resins, polycarbonate resins, cellulosic resins, polyester resins, and acrylic resins.

Preferably, the substrate is optically isotropic, and therefore the conductive layer can be used as a conductive layer with an isotropic substrate in a polarizing plate with an optical compensation layer. Materials constituting an optically isotropic base material (isotropic base material) include, for example, a material whose main skeleton is a resin having no conjugate system such as a norbornene-based resin and an olefin-based resin, a lactone ring, and a glutar. Examples thereof include a material having a cyclic structure such as an imide ring in the main chain of an acrylic resin. When such a material is used, when an isotropic base material is formed, the expression of the phase difference due to the orientation of the molecular chains can be suppressed to be small.

The thickness of the base material is preferably 10 μm to 200 μm, and more preferably 20 μm to 60 μm.

B-4. Others Any suitable adhesive layer or adhesive layer is used for laminating each layer constituting the polarizing plate with an optical compensation layer of the present invention. The pressure-sensitive adhesive layer is typically formed of an acrylic pressure-sensitive adhesive. The adhesive layer is typically formed of a polyvinyl alcohol-based adhesive.

Although not shown, an adhesive layer may be provided on the optical compensation layer 10A side of the polarizing plate 100 with an optical compensation layer. Since the pressure-sensitive adhesive layer is provided in advance, it can be easily attached to another optical member (for example, an organic EL cell). It is preferable that a release film is bonded to the surface of the pressure-sensitive adhesive layer until it is used.

C. Image Display Device The image display device of the present invention includes a display cell and a polarizing plate with an optical compensation layer according to the above item B on the visual recognition side of the display cell. The polarizing plate with an optical compensation layer is laminated so that the optical compensation layer is on the display cell side (the polarizing element is on the visual recognition side). In an image display device including a polarizing plate with an optical compensation layer having a conductive layer, the conductive layer functions as a touch panel sensor, so that a touch sensor is placed between a display cell (for example, a liquid crystal cell or an organic EL cell) and a polarizing element. A built-in so-called image display device with an inner touch panel may be configured.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples. The measurement method of each characteristic is as follows. Unless otherwise specified, "parts" and "%" in Examples and Comparative Examples are based on weight.
(1) Thickness Measured using a dial gauge (manufactured by PEACOCK, product name "DG-205 type pds-2").
(2) Phase difference A sample of 50 mm × 50 mm was cut out from each retardation plate and used as a measurement sample, and measured using Axoscan manufactured by Axometrics. The measurement wavelengths were 450 nm, 550 nm and 650 nm, and the measurement temperature was 23 ° C.
Further, the average refractive index was measured using an Abbe refractive index meter manufactured by Atago Co., Ltd., and the refractive indexes nx, ny, nz, and Nz coefficients were calculated from the obtained phase difference values.

[Example 1]
1. 1. Preparation of Polycarbonate Resin Polymerization was carried out using a batch polymerization apparatus consisting of two vertical reactors equipped with a stirring blade and a reflux condenser controlled at 100 ° C. Bis [9- (2-phenoxycarbonylethyl) fluoren-9-yl] methane (Compound 3) 29.60 parts by mass (0.046 mol), ISB 29.21 parts by mass (0.200 mol), SPG 42.28 parts by mass Parts (0.139 mol), DPC 63.77 parts by mass (0.298 mol), and calcium acetate monohydrate 1.19 × 10 ⁻² parts by mass (6.78 × ^10-5 mol) were charged. After substituting nitrogen under reduced pressure in the reactor, heating was performed with a heat medium, and stirring was started when the internal temperature reached 100 ° C. The internal temperature was brought to 220 ° C. 40 minutes after the start of the temperature rise, and the depressurization was started at the same time as controlling to maintain this temperature, and the temperature was 13.3 kPa 90 minutes after reaching 220 ° C. The phenol vapor produced by the polymerization reaction was guided to a reflux condenser at 100 ° C., the monomer component contained in a small amount in the phenol vapor was returned to the reactor, and the non-condensed phenol vapor was guided to a condenser at 45 ° C. for recovery. Nitrogen was introduced into the first reactor and the pressure was once restored to atmospheric pressure, and then the oligomerized reaction solution in the first reactor was transferred to the second reactor. Then, the temperature rise and depressurization in the second reactor were started, and the internal temperature was 240 ° C. and the pressure was 0.2 kPa in 50 minutes. Then, the polymerization was allowed to proceed until the stirring power became a predetermined value. When the predetermined power was reached, nitrogen was introduced into the reactor to repressurize, the produced polyester carbonate was extruded into water, and the strands were cut to obtain pellets.
The glass transition temperature of the obtained polycarbonate resin was 130 ° C.
2. 2. Fabrication of retardation plate (1) Fabrication of retardation film used as the first retardation layer A single-screw extruder (manufactured by Isuzu Kakohki Co., Ltd., screw diameter 25 mm, cylinder set temperature: 220 ° C.), Polycarbonate resin with a length of 3 m, a width of 300 mm, and a thickness of 120 μm using a film-forming device equipped with a T-die (width 300 mm, set temperature: 220 ° C), chill roll (set temperature: 120 to 130 ° C), and a winder. A film was made. The obtained polycarbonate film was cut into a length of 150 mm and a width of 120 mm, and was subjected to fixed-end uniaxial stretching at a temperature of 134 ° C. and a magnification of 2.8 times using a lab stretcher KARO IV (manufactured by Bruckner). (Thickness: 47 μm) was obtained.
The obtained retardation film exhibited a refractive index characteristic of nx>ny> nz, Re (450) was 119 nm, Re (550) was 139 nm, Re (650) was 147 nm, and Nz (450) was 1. 08, Nz (550) was 1.13, and Nz (650) was 1.15.
The Re (450) / Re (550) of the obtained retardation film was 0.86, and the Re (650) / Re (550) was 1.06.
(2) Preparation of Liquid Crystal Solidified Layer Used as Second Phase Difference Layer A liquid crystal coating liquid was prepared according to Example 2 of Japanese Patent No. 5401032, and a liquid crystal solidified layer (thickness: 0.9 μm) was formed on the substrate. ..
The obtained liquid crystal solidified layer had a Re (550) of 0 nm and an Rth (550) of −45 nm, and exhibited a refractive index characteristic of nz> nx = ny. The Rth (450) / Rth (550) of the liquid crystal solidified layer was 0.79, and the Rth (650) / Rth (550) was 1.07.
(3) Preparation of retardation plate After the liquid crystal solidifying layer is bonded to the retardation film via an acrylic pressure-sensitive adhesive, the base film is removed and the liquid crystal solidifying layer is transferred to the retardation film. A phase difference plate (thickness: 48 μm) was obtained.
The obtained retardation plate has Re (450) of 120 nm, Re (550) of 141 nm, Re (650) of 150 nm, Nz (450) of 0.76, Nz (550) of 0.79, and Nz ( 650) was 0.81.
3. 3. Fabrication of Conductive Layer A transparent conductive layer (thickness 20 nm) made of indium-tin composite oxide is formed on the surface of the retardation plate on the liquid crystal solidified layer side by sputtering, and the retardation film / liquid crystal solidified layer / conductive layer is laminated. The body was made. The specific procedure is as follows: 10 wt% oxidation under vacuum atmosphere (0.40 Pa) with Ar and O ₂ (flow ratio Ar: O ₂ = 99.9: 0.1) introduced. RF superimposition DC magnetron sputtering method (discharge voltage 150V, RF frequency 13.56MHz, DC) with a film temperature of 130 ° C and a horizontal magnetic field of 100mT using a sintered body of tin and 90% by weight of indium oxide as a target. The ratio of RF power to power (RF power / DC power) was 0.8). The obtained transparent conductive layer was heated in a warm air oven at 150 ° C. to perform crystal conversion treatment.
4. Fabrication of Polarizer A long roll of polyvinyl alcohol (PVA) resin film (manufactured by Kuraray, product name "PE3000") with a thickness of 30 μm is uniaxially oriented in the longitudinal direction so as to be 5.9 times in the longitudinal direction by a roll stretching machine. While being stretched, it was simultaneously swollen, stained, crosslinked, and washed, and finally dried to prepare a polarizing element having a thickness of 12 μm.
Specifically, the swelling treatment was carried out by stretching 2.2 times while treating with pure water at 20 ° C. Next, the dyeing treatment was carried out in an aqueous solution at 30 ° C. in which the weight ratio of iodine and potassium iodide was adjusted so that the simple substance transmittance of the obtained polarizing element was 45.0% and the weight ratio was 1: 7. However, it was stretched 1.4 times. Further, the cross-linking treatment adopted a two-step cross-linking treatment, and the first-step cross-linking treatment was carried out 1.2 times while being treated with an aqueous solution in which boric acid and potassium iodide were dissolved at 40 ° C. The boric acid content of the aqueous solution of the first-step crosslinking treatment was 5.0% by weight, and the potassium iodide content was 3.0% by weight. The second-step cross-linking treatment was carried out by stretching 1.6 times while treating with an aqueous solution in which boric acid and potassium iodide were dissolved at 65 ° C. The boric acid content of the aqueous solution of the second step cross-linking treatment was 4.3% by weight, and the potassium iodide content was 5.0% by weight. The washing treatment was carried out with an aqueous potassium iodide solution at 20 ° C. The potassium iodide content of the aqueous solution of the washing treatment was set to 2.6% by weight. Finally, the drying treatment was carried out at 70 ° C. for 5 minutes to obtain a stator.
5. Preparation of Polarizing Plate with Optical Compensation Layer A triacetyl cellulose film (thickness 40 μm, manufactured by Konica Minolta, trade name “KC4UYW”) was attached to one side of the above-mentioned polarizing element via a polyvinyl alcohol-based adhesive. The retardation film side of the retardation plate was bonded to the other side of the polarizing element via a polyvinyl alcohol-based adhesive. Here, the retardation film was bonded so that the slow axis of the retardation film was 45 ° counterclockwise with respect to the absorption axis of the substituent.
In this way, a polarizing plate with an optical compensation layer having a laminated structure of a protective layer / a splitter / a retardation film / a liquid crystal solidified layer / a conductive layer was obtained.
6. Preparation of substitute for image display device A substitute for organic EL display device was prepared as follows. An aluminum thin-film film (manufactured by Toray Film Processing Co., Ltd., trade name "DMS thin-film X-42", thickness 50 μm) was attached to a glass plate with an adhesive to use it as a substitute for an organic EL display device. A pressure-sensitive adhesive layer was formed on the conductive layer side of the obtained polarizing plate with an optical compensation layer with an acrylic pressure-sensitive adhesive, cut out to a size of 50 mm × 50 mm, and mounted on an organic EL display device substitute.

[Example 2]
A retardation plate was obtained in the same manner as in Example 1 except that the liquid crystal solidifying layer formed by setting the thickness of the liquid crystal solidifying layer to 1.1 μm was used in the step of manufacturing the retardation plate.
Re (550) of the liquid crystal solidified layer is 0 nm, Rth (550) is -55 nm, Rth (450) / Rth (550) is 0.80, and Rth (650) / Rth (550) is 1.03. there were.
The obtained retardation plate has Re (450) of 120 nm, Re (550) of 141 nm, Re (650) of 150 nm, Nz (450) of 0.71, Nz (550) of 0.74, and Nz ( 650) was 0.76.
A polarizing plate with an optical compensation layer and a substitute for an organic EL display device were obtained in the same manner as in Example 1 except that the above retardation plate was used.

[Example 3]
A retardation plate was obtained in the same manner as in Example 1 except that the liquid crystal solidifying layer formed by setting the thickness of the liquid crystal solidifying layer to 1.3 μm was used in the step of manufacturing the retardation plate.
Re (550) of the liquid crystal solidified layer is 0 nm, Rth (550) is -65 nm, Rth (450) / Rth (550) is 0.80, and Rth (650) / Rth (550) is 1.03. there were.
The obtained retardation plate has Re (450) of 120 nm, Re (550) of 141 nm, Re (650) of 150 nm, Nz (450) of 0.66, Nz (550) of 0.67, and Nz ( 650) was 0.70.
A polarizing plate with an optical compensation layer and a substitute for an organic EL display device were obtained in the same manner as in Example 1 except that the above retardation plate was used.

[Example 4]
A retardation plate was obtained in the same manner as in Example 1 except that the liquid crystal solidifying layer formed by setting the thickness of the liquid crystal solidifying layer to 1.7 μm was used in the step of manufacturing the retardation plate.
Re (550) of the liquid crystal solidified layer is 0 nm, Rth (550) is -80 nm, Rth (450) / Rth (550) is 0.80, and Rth (650) / Rth (550) is 1.03. there were.
The obtained retardation plate has Re (450) of 121 nm, Re (550) of 142 m, Re (650) of 150 nm, Nz (450) of 0.59, Nz (550) of 0.60, and Nz ( 650) was 0.62.
A polarizing plate with an optical compensation layer and a substitute for an organic EL display device were obtained in the same manner as in Example 1 except that the above retardation plate was used.

[Example 5]
A retardation plate was obtained in the same manner as in Example 1 except that the liquid crystal solidifying layer formed by setting the thickness of the liquid crystal solidifying layer to 1.9 μm was used in the step of manufacturing the retardation plate.
The liquid crystal solidified layer has Re (550) of 0 nm, Rth (550) of −90 nm, Rth (450) / Rth (550) of 0.80, and Rth (650) / Rth (550) of 1.03. there were.
The obtained retardation plate has Re (450) of 120 nm, Re (550) of 141 m, Re (650) of 149 nm, Nz (450) of 0.47, Nz (550) of 0.48, and Nz ( 650) was 0.50.
A polarizing plate with an optical compensation layer and a substitute for an organic EL display device were obtained in the same manner as in Example 1 except that the above retardation plate was used.

上記液晶固化層を用いたこと以外は実施例１と同様にして位相差板を得た。
得られた位相差板のＲｅ（４５０）は１１９ｎｍ、Ｒｅ（５５０）は１３９ｎｍ、Ｒｅ（６５０）は１４７ｎｍであり、Ｎｚ（４５０）は０．３１、Ｎｚ（５５０）は０．５２、Ｎｚ（６５０）は０．６０であった。
上記位相差板を用いたこと以外は実施例１と同様にして光学補償層付偏光板および有機ＥＬ表示装置代替品を得た。 [Comparative Example 1]
20 parts by weight of the side chain liquid crystal polymer represented by the following chemical formula (I) (numbers 65 and 35 in the formula represent mol% of the monomer unit and are conveniently represented by a block polymer: weight average molecular weight 5000). 80 parts by weight of a polymerizable liquid crystal (BASF: trade name Palocolor LC242) showing a nematic liquid crystal phase and 5 parts by weight of a photopolymerization initiator (Ciba Specialty Chemicals: trade name IrgaCure 907) are dissolved in 200 parts by weight of cyclopentanone. The liquid crystal coating liquid was prepared. Then, the liquid crystal is formed by applying the coating liquid to a base film (norbornene-based resin film: manufactured by Nippon Zeon Corporation, trade name "Zeonex") with a bar coater, and then heating and drying at 80 ° C. for 4 minutes. Oriented. By irradiating this liquid crystal layer with ultraviolet rays and curing the liquid crystal layer, a liquid crystal solidified layer (thickness: 1 μm) to be a second retardation layer was formed on the base material. Re (550) of this layer is 0 nm, Rth (550) is -100 nm (nx: 1.5326, ny: 1.5326, nz: 1.6550), and exhibits a refractive index characteristic of nz> nx = ny. rice field.

A retardation plate was obtained in the same manner as in Example 1 except that the liquid crystal solidified layer was used.
The obtained retardation plate has Re (450) of 119 nm, Re (550) of 139 nm, Re (650) of 147 nm, Nz (450) of 0.31, Nz (550) of 0.52, and Nz ( 650) was 0.60.
A polarizing plate with an optical compensation layer and a substitute for an organic EL display device were obtained in the same manner as in Example 1 except that the above retardation plate was used.

[Comparative Example 2]
A polarizing plate with an optical compensation layer and a substitute for an organic EL display device were obtained in the same manner as in Example 1 except that the retardation film produced in the same manner as in Example 1 was used as the retardation plate.

<Evaluation>
The following evaluations were made on the organic EL display device substitutes of Examples and Comparative Examples. The evaluation results are shown in Table 1.
(1) Reflectance and reflective hue Using a substitute for an organic EL display device as a sample, the front reflectance and the front reflection hue were measured using a spectrophotometer CM-2600d manufactured by Konica Minolta Co., Ltd. Front reflectance is measured by the SCI method. For the specular hue, the distance Δa ^* b ^* from the achromatic color on the a ^* b ^* chromaticity diagram was evaluated.
(2) Oblique Reflectance and Reflected Hue Using a substitute for an organic EL display device as a sample, the oblique reflectance and reflected hue were measured using DMS 505 manufactured by Konica Minolta Co., Ltd. For the reflectance in the oblique direction, the average value of the visual reflectance Y at four points having a polar angle of 60 °, an azimuth angle of 0 °, 45 °, 90 ° and 135 ° was evaluated. The oblique reflection hue is measured at an angle of 60 ° with respect to the phase advance axis and the slow phase axis on the a ^* b ^* chromaticity diagram. The distance between two points Δa ^* b ^* of the reflected hue of was evaluated.

The organic EL display device substitute of the example had lower oblique reflection intensity and reflection hue than the organic EL display device substitute of the comparative example, and was good.

The polarizing plate with an optical compensation layer having a retardation plate of the present invention is suitably used for an image display device such as an organic EL panel.

10 Phase difference plate 11 First phase difference layer 12 Second phase difference layer 20 Polarizer 30 Protective layer 100 Polarizing plate with optical compensation layer

Claims (1)

The in-plane phase difference Re satisfies 100 nm ≤ Re (550) ≤ 160 nm, Re (450) / Re (550) ≤ 1, and Re (650) / Re (550) ≥ 1.
The Nz coefficient satisfies Nz (550) <1, 0 ≦ | Nz (450) -Nz (550) | ≦ 0.1 and 0 ≦ | Nz (650) -Nz (550) | ≦ 0.1. ,
Phase difference plate:
Here, Re (450), Re (550), and Re (650) represent in-plane phase differences measured with light having wavelengths of 450 nm, 550 nm, and 650 nm at 23 ° C., respectively, and represent Nz (450) and Nz. (550) and Nz (650) represent Nz coefficients measured with light at wavelengths of 450 nm, 550 nm, and 650 nm at 23 ° C., respectively.

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