WO2017094530A1

WO2017094530A1 - Phase difference layer-provided polarizing plate and image display device

Info

Publication number: WO2017094530A1
Application number: PCT/JP2016/084247
Authority: WO
Inventors: 敏行飯田
Original assignee: 日東電工株式会社
Priority date: 2015-11-30
Filing date: 2016-11-18
Publication date: 2017-06-08
Also published as: CN117908178A

Abstract

Provided is a phase difference layer-provided polarizing plate with which it is possible to create a liquid crystal display that has superior visibility when viewed through an optical member, said optical member having a polarizing effect. A phase difference layer-provided polarizing plate according to the present invention has an elongated shape and comprises a phase difference layer, a polarizer, and an adhesive layer, in this order. The in-plane phase difference Re(550) of the phase difference layer is 100nm-180nm and satisfies the relationship Re(450)<Re(550)<Re(650); the indicatrix of the phase difference layer demonstrates the relationship nx>nz>ny; and the Nz coefficient is 0.2-0.8.

Description

Polarizing plate with retardation layer and image display device

The present invention relates to a polarizing plate with a retardation layer and an image display device using the polarizing plate with a retardation layer.

In recent years, image display devices such as mobile phones, smartphones, tablet personal computers (PCs), car navigation systems, digital signage, window displays, etc. have been increasingly used under strong external light. When the image display device is used outdoors as described above, when the viewer views the image display device wearing polarized sunglasses, the transmission axis direction of the polarized sunglasses and the emission of the image display device depend on the viewing angle. As a result, the screen becomes black and the display image may not be visually recognized. In order to solve such a problem, a technique has been proposed in which a λ / 4 plate or an ultrahigh retardation film is disposed on the viewing side of the image display device. However, there is still much room for improvement regarding the visibility when the viewer sees the image display device wearing polarized sunglasses.

JP 2005-352068 A JP2011-107198A

The present invention has been made to solve the above-described conventional problems, and its object is to achieve a phase difference that can realize a liquid crystal display device having excellent visibility when viewed through an optical member having a polarizing action. It is providing the polarizing plate with a layer.

The polarizing plate with a retardation layer of the present invention is long, and includes a retardation layer, a polarizer, and an adhesive layer in this order. The in-plane retardation Re (550) of the retardation layer is 100 nm to 180 nm, satisfies the relationship of Re (450) <Re (550) <Re (650), and the refractive index ellipsoid of the retardation layer Indicates a relationship of nx>nz> ny, and the Nz coefficient is 0.2 to 0.8.
In one embodiment, an angle formed between the slow axis of the retardation layer and the absorption axis of the polarizer is 125 ° to 145 °.
In one embodiment, the polarizing plate with a retardation layer further includes another retardation layer between the polarizer and the pressure-sensitive adhesive layer. The in-plane retardation Re (550) of the other retardation layer is 100 nm to 180 nm, and the refractive index ellipsoid of the other retardation layer shows a relationship of nx> ny ≧ nz. In one embodiment, the slow axis of the retardation layer and the slow axis of the other retardation layer are substantially orthogonal to each other.
In one embodiment, the in-plane retardation Re (550) of the other retardation layer is 150 nm to 350 nm, and the refractive index ellipsoid of the other retardation layer has a relationship of nx>nz> ny. Indicates. In one embodiment, the angle formed between the slow axis of the retardation layer and the slow axis of the other retardation layer is 35 ° to 55 °.
In one embodiment, the in-plane retardation of the other retardation layer satisfies a relationship of Re (450) <Re (550) <Re (650).
In one embodiment, a separator is temporarily attached to the outside of the pressure-sensitive adhesive layer in the polarizing plate with a retardation layer.
In one embodiment, the polarizing plate with a retardation layer has a roll shape.
According to another aspect of the present invention, an image display device is provided. The image display device includes the cut polarizing plate with a retardation layer on the viewing side, and the retardation layer of the polarizing plate with the retardation layer is disposed on the viewing side.
In one embodiment, the image display device is a liquid crystal display device or an organic electroluminescence display device including a backlight source having a discontinuous emission spectrum.

According to an embodiment of the present invention, a polarizing layer is disposed by placing a retardation layer having specific wavelength dispersion characteristics, an in-plane retardation, a refractive index ellipsoid, and an Nz coefficient on the viewing side of the polarizer. A polarizing plate with a retardation layer capable of realizing a liquid crystal display device having excellent visibility when viewed through an optical member having a retardation can be obtained.

It is a schematic sectional drawing of the polarizing plate with a phase difference layer by one Embodiment of this invention. It is a schematic sectional drawing of the polarizing plate with retardation layer by another embodiment of this invention. It is a figure which shows typically an example of the emission spectrum of the backlight light source which can be used for the liquid crystal display device by embodiment of this invention. It is a figure which shows typically an example of the emission spectrum of the conventional backlight light source.

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

(Definition of terms and symbols)
The definitions of terms and symbols in this specification are as follows.
(1) Refractive index (nx, ny, nz)
“Nx” is the refractive index in the direction in which the in-plane refractive index is maximum (ie, the slow axis direction), and “ny” is the direction orthogonal to the slow axis in the plane (ie, the fast axis direction). “Nz” is the refractive index in the thickness direction.
(2) In-plane retardation (Re)
“Re (λ)” is the in-plane retardation of the film measured with light having a wavelength of λ nm at 23 ° C. For example, “Re (450)” is the in-plane retardation of the film measured with light having a wavelength of 450 nm at 23 ° C. Re (λ) is determined by the formula: Re = (nx−ny) × d, where d (nm) is the thickness of the film.
(3) Thickness direction retardation (Rth)
“Rth (λ)” is a retardation in the thickness direction of the film measured with light having a wavelength of 550 nm at 23 ° C. For example, “Rth (450)” is the retardation in the thickness direction of the film measured with light having a wavelength of 450 nm at 23 ° C. Rth (λ) is determined by the formula: Rth = (nx−nz) × d, where d (nm) is the thickness of the film.
(4) Nz coefficient The Nz coefficient is obtained by Nz = Rth / Re.
(5) nx = ny, nx = nz, ny = nz
nx = ny includes not only the case where nx and ny are completely the same, but also the case where nx and ny are substantially the same. The same applies to the relationship of nx = nz and ny = nz.
(6) Substantially orthogonal or parallel The expressions “substantially orthogonal” and “substantially orthogonal” include the case where the angle between the two directions is 90 ° ± 10 °, preferably 90 ° ± 7 °. And more preferably 90 ° ± 5 °. The expressions “substantially parallel” and “substantially parallel” include the case where the angle between two directions is 0 ° ± 10 °, preferably 0 ° ± 7 °, more preferably 0 ° ± 5 °. Furthermore, the term “orthogonal” or “parallel” may include a substantially orthogonal state or a substantially parallel state.
(7) Angle When this specification refers to an angle, the angle includes angles in both clockwise and counterclockwise directions unless otherwise specified.
(8) Long shape “Long shape” means an elongated shape having a sufficiently long length with respect to the width. For example, the elongated shape has a length of 10 times or more, preferably 20 times or more with respect to the width. Includes shape.
(9) Roll-to-roll “Roll-to-roll” means that the rolls are transported together and aligned in the longitudinal direction.

A. Polarizing plate with retardation layer A-1. FIG. 1 is a schematic sectional view of a polarizing plate with a retardation layer according to one embodiment of the present invention. In the drawing, the ratio of the thickness of each layer is different from the actual one for the sake of easy understanding. The polarizing plate 100 with a retardation layer of the present embodiment includes a retardation layer 10, a polarizer 20, and an adhesive layer 30 in this order. In the embodiment of the present invention, the in-plane retardation Re (550) of the retardation layer 10 is 100 nm to 180 nm, preferably 110 nm to 170 nm, more preferably 120 nm to 160 nm, and particularly preferably 135 nm to 155 nm. Furthermore, the retardation layer 10 satisfies the relationship of Re (450) <Re (550) <Re (650). In addition, the refractive index ellipsoid of the retardation layer 10 shows a relationship of nx>nz> ny, and the Nz coefficient is 0.2 to 0.8, preferably 0.3 to 0.7, more preferably Is 0.4 to 0.6, more preferably about 0.5. The angle formed by the slow axis of the retardation layer 10 and the absorption axis of the polarizer 20 is preferably 125 ° to 145 °, more preferably 128 ° to 142 °, and still more preferably 130 ° to 140 °. Particularly preferably 132 ° to 138 °, particularly preferably 134 ° to 136 °, and most preferably about 135 °.

FIG. 2 is a schematic cross-sectional view of a polarizing plate with a retardation layer according to another embodiment of the present invention. The retardation layer-attached polarizing plate 101 of this embodiment further includes another retardation layer 50 between the polarizer 20 and the pressure-sensitive adhesive layer 30. Hereinafter, for convenience, the retardation layer 10 may be referred to as a first retardation layer, and the other retardation layer 50 may be referred to as a second retardation layer. The in-plane retardation Re (550) of the second retardation layer 50 is preferably 100 nm to 180 nm, more preferably 110 nm to 170 nm, still more preferably 120 nm to 160 nm, and particularly preferably 135 nm to 155 nm. is there. Further, the second retardation layer 50 preferably satisfies the relationship of Re (450) <Re (550) <Re (650). In addition, the refractive index ellipsoid of the second retardation layer 50 preferably exhibits a relationship of nx> ny ≧ nz.

The in-plane retardation Re (550) of the second retardation layer 50 may be preferably 150 nm to 350 nm. In this case, the refractive index ellipsoid of the second retardation layer preferably exhibits a relationship of nx> nz> ny. The in-plane retardation Re (550) of the second retardation layer 50 is more preferably 180 nm to 320 nm, and further preferably 240 nm to 300 nm. Also in this case, the second retardation layer preferably satisfies the relationship of Re (450) <Re (550) <Re (650).

In one embodiment, the slow axis of the first retardation layer 10 and the slow axis of the second retardation layer 50 are substantially orthogonal. In this case, the angle formed between the slow axis of the second retardation layer 50 and the absorption axis of the polarizer 20 is preferably 35 ° to 55 °, more preferably 38 ° to 52 °, and still more preferably. Is from 40 ° to 50 °, particularly preferably from 42 ° to 48 °, particularly preferably from 44 ° to 46 °, most preferably about 45 °. In this case, the second retardation layer preferably has an in-plane retardation Re (550) of 100 nm to 180 nm, preferably satisfies the relationship of Re (450) <Re (550) <Re (650), and is refracted. The rate ellipsoid preferably exhibits a relationship of nx> ny ≧ nz. According to such a configuration, the polarizing plate with a retardation layer can function well as an antireflection film of an organic EL display device. In another embodiment, the angle formed by the slow axis of the first retardation layer 10 and the slow axis of the second retardation layer 50 is preferably 35 ° to 55 °, and more preferably 38 °. It is preferably from 45 ° to 52 °, more preferably from 40 ° to 50 °, particularly preferably from 42 ° to 48 °, particularly preferably from 44 ° to 46 °, and most preferably about 45 °. In this case, the slow axis of the second retardation layer 50 and the absorption axis of the polarizer 20 are substantially orthogonal. In this case, the second retardation layer preferably has an in-plane retardation Re (550) of 150 nm to 350 nm, preferably satisfies the relationship of Re (450) <Re (550) <Re (650), and is refracted. The rate ellipsoid preferably exhibits a relationship of nx> nz> ny. According to such a configuration, the polarizing plate with the retardation layer can widen the viewing angle of the liquid crystal display device.

Although not clear from the drawings, the polarizing plate with a retardation layer of the embodiment of the present invention is long. Therefore, the constituent elements of the polarizing plate with the retardation layer (for example, the polarizer, the first retardation layer, and the second retardation layer) are also long. The polarizer typically has an absorption axis in the longitudinal direction. Accordingly, both the first retardation layer and the second retardation layer may have a slow axis so as to make the predetermined angle with respect to the longitudinal direction (that is, in an oblique direction). In one embodiment, the polarizing plate with a retardation layer is wound in a roll shape. The polarizing plate with a retardation layer, for example, constitutes a long retardation film constituting the first retardation layer 10 and a long polarizer 20 and a second retardation layer 50 as necessary. It can be produced by laminating a long retardation film by roll-to-roll.

As necessary, between the polarizer 20 and the first retardation layer 10 and / or between the polarizer 20 and the pressure-sensitive adhesive layer 30 (the second retardation layer 50 when present). A protective film (not shown) may be provided. Needless to say, the protective film is also long.

If necessary, a conductive layer (not shown) may be provided between the polarizer 20 (the second retardation layer 50 if present) and the pressure-sensitive adhesive layer 30. An image display device using a polarizing plate with a retardation layer by providing a conductive layer is a so-called inner touch panel in which a touch sensor is incorporated between a display cell (for example, a liquid crystal cell or an organic EL cell) and a polarizer. A mold input display device can be constructed.

Practically, a separator 40 is temporarily attached to the outside of the pressure-sensitive adhesive layer 30 to protect the pressure-sensitive adhesive layer and enable roll formation until the polarizing plate with a retardation layer is used.

Hereinafter, each layer of the polarizing plate with a retardation layer will be described.

A-2. First retardation layer As described above, the in-plane retardation Re (550) of the first retardation layer 10 is 100 nm to 180 nm, preferably 110 nm to 170 nm, more preferably 120 nm to 160 nm, Particularly preferred is 135 nm to 155 nm. That is, the first retardation layer can function as a so-called λ / 4 plate. Further, the first retardation layer is disposed on the side opposite to the pressure-sensitive adhesive layer of the polarizer (so that the first retardation layer is on the viewing side when the polarizing plate with a retardation layer is applied to an image display device). Therefore, the first retardation layer has a function of converting linearly polarized light emitted from the polarizer to the viewer side into elliptically polarized light or circularly polarized light. Thus, by arranging the first retardation layer that can function as a λ / 4 plate so as to be closer to the viewing side than the polarizer in the specific axial relationship as described above, an optical member having a polarizing action ( For example, an image display device having excellent visibility can be realized even when the display screen is viewed through polarized sunglasses). Therefore, the image display apparatus using the polarizing plate with a retardation layer of the present invention can be suitably used outdoors.

Further, as described above, the first retardation layer satisfies the relationship of Re (450) <Re (550) <Re (650). That is, the first retardation layer shows the wavelength dependence of reverse dispersion in which the retardation value increases with the wavelength of the measurement light. Re (450) / Re (550) of the first retardation layer is preferably 0.8 or more and less than 1.0, and more preferably 0.8 to 0.95. Re (550) / Re (650) is preferably 0.8 or more and less than 1.0, and more preferably 0.8 to 0.97.

In the first retardation layer, the refractive index ellipsoid has a relationship of nx> nz> ny and has a slow axis as described above. As described above, the angle formed between the slow axis of the first retardation layer 10 and the absorption axis of the first polarizer 20 is preferably 125 ° to 145 °, more preferably 128 ° to 142 °. More preferably 130 ° to 140 °, particularly preferably 132 ° to 138 °, particularly preferably 134 ° to 136 °, and most preferably about 135 °. When the angle is in such a range, by using the λ / 4 plate as the first retardation layer, very excellent circular polarization characteristics (as a result, very excellent antireflection characteristics) can be realized. .

The Nz coefficient of the first retardation layer is preferably 0.2 to 0.8, more preferably 0.3 to 0.7, still more preferably 0.4 to 0.6, particularly Preferably it is about 0.5. By satisfying such a relationship, in an image display device to which a polarizing plate with a retardation layer is applied, coloring when viewed from an oblique direction through an optical member having a polarizing action (for example, polarized sunglasses) is suppressed. Has the advantage of being

The absolute value of the photoelastic coefficient of the first retardation layer is preferably 2 × 10 ⁻¹¹ m ² / N or less, more preferably 2.0 × 10 ⁻¹³ m ² / N to 1.5 × 10 ^−11. m ² / N, more preferably from ^{^{^{1.0 × 10 -12 m 2 /N~1.2×10 -11}}} m 2 / N resin. When the absolute value of the photoelastic coefficient is in such a range, a phase difference change is unlikely to occur when a shrinkage stress is generated during heating. As a result, the thermal unevenness of the image display device using the retardation layer-attached polarizing plate can be well prevented.

The thickness of the first retardation layer can be set so as to function most appropriately as a λ / 4 plate. In other words, the thickness can be set so as to obtain a desired in-plane retardation. Specifically, the thickness is preferably 1 μm to 80 μm, more preferably 10 μm to 80 μm, still more preferably 10 μm to 60 μm, and particularly preferably 30 μm to 50 μm.

The first retardation layer is formed of any appropriate resin that can satisfy the above characteristics. Examples of the resin that forms the first retardation layer include polycarbonate resins, polyvinyl acetal resins, cycloolefin resins, acrylic resins, and cellulose ester resins. Polycarbonate resin is preferable.

As the polycarbonate resin, any appropriate polycarbonate resin can be used as long as the effects of the present invention can be obtained. Preferably, the polycarbonate resin includes a structural unit derived from a fluorene-based dihydroxy compound, a structural unit derived from an isosorbide-based dihydroxy compound, an alicyclic diol, an alicyclic dimethanol, di, tri, or polyethylene glycol, and an alkylene. A structural unit derived from at least one dihydroxy compound selected from the group consisting of glycol or spiroglycol. Preferably, the polycarbonate resin is derived from a structural unit derived from a fluorene-based dihydroxy compound, a structural unit derived from an isosorbide-based dihydroxy compound, a structural unit derived from an alicyclic dimethanol and / or a di-, tri- or polyethylene glycol. More preferably, a structural unit derived from a fluorene-based dihydroxy compound, a structural unit derived from an isosorbide-based dihydroxy compound, and a structural unit derived from di, tri, or polyethylene glycol. The polycarbonate resin may contain structural units derived from other dihydroxy compounds as necessary. Details of the polycarbonate resin that can be suitably used in the present invention are described in, for example, Japanese Patent Application Laid-Open Nos. 2014-10291 and 2014-26266, and the description is incorporated herein by reference. The

The glass transition temperature of the polycarbonate resin is preferably 110 ° C. or higher and 250 ° C. or lower, more preferably 120 ° C. or higher and 230 ° C. or lower. If the glass transition temperature is excessively low, the heat resistance tends to deteriorate, there is a possibility of causing a dimensional change after film formation, and the image quality of the obtained liquid crystal display device may be lowered. If the glass transition temperature is excessively high, the molding stability at the time of film molding may deteriorate, and the transparency of the film may be impaired. The glass transition temperature is determined according to JIS K 7121 (1987).

The molecular weight of the polycarbonate resin can be represented by a reduced viscosity. The reduced viscosity is measured using a Ubbelohde viscometer at a temperature of 20.0 ° C. ± 0.1 ° C., using methylene chloride as a solvent, precisely adjusting the polycarbonate concentration to 0.6 g / dL. The lower limit of the reduced viscosity is usually preferably 0.30 dL / g, more preferably 0.35 dL / g or more. The upper limit of the reduced viscosity is usually preferably 1.20 dL / g, more preferably 1.00 dL / g, still more preferably 0.80 dL / g. If the reduced viscosity is less than the lower limit, there may be a problem that the mechanical strength of the molded product is reduced. On the other hand, if the reduced viscosity is larger than the upper limit, the fluidity at the time of molding is lowered, and there may be a problem that productivity and moldability are lowered.

The retardation film constituting the first retardation layer can be obtained, for example, by stretching a film formed from the polycarbonate resin. Any appropriate molding method can be adopted as a method of forming a film from a polycarbonate-based resin. Specific examples include compression molding methods, transfer molding methods, injection molding methods, extrusion molding methods, blow molding methods, powder molding methods, FRP molding methods, cast coating methods (for example, casting methods), calendar molding methods, and hot presses. Law. Extrusion molding or cast coating is preferred. This is because the smoothness of the resulting film can be improved and good optical uniformity can be obtained. The molding conditions can be appropriately set according to the composition and type of the resin used, the properties desired for the retardation film, and the like.

The thickness of the resin film (unstretched film) can be set to any appropriate value depending on the desired thickness of the obtained retardation film, the desired optical properties, the stretching conditions described later, and the like. The thickness is preferably 50 μm to 300 μm.

Any appropriate stretching method and stretching conditions (for example, stretching temperature, stretching ratio, stretching direction) may be employed for the stretching. Specifically, various stretching methods such as free end stretching, fixed end stretching, free end contraction, and fixed end contraction can be used singly or simultaneously or sequentially. The stretching direction can also be performed in various directions and dimensions such as a length direction, a width direction, a thickness direction, and an oblique direction.

A retardation film having the desired optical characteristics (for example, refractive index characteristics, in-plane retardation, Nz coefficient) can be obtained by appropriately selecting the stretching method and stretching conditions.

In one embodiment, the retardation film can be produced by continuously stretching a long resin film obliquely in a direction at a predetermined angle with respect to the longitudinal direction. By adopting oblique stretching, a long stretched film having an orientation angle of a predetermined angle with respect to the longitudinal direction of the film (slow axis in the direction of the predetermined angle) is obtained. For example, with a polarizer Roll-to-roll is possible at the time of lamination, and the manufacturing process can be simplified. The predetermined angle may be an angle formed by the absorption axis of the polarizer (that is, the longitudinal direction of the long film) and the slow axis of the first retardation layer. As described above, the angle is preferably 125 ° to 145 °, more preferably 128 ° to 142 °, still more preferably 130 ° to 140 °, and particularly preferably 132 ° to 138 °. Especially preferred is 134 ° to 136 °, most preferred about 135 °.

Examples of the stretching machine used for the oblique stretching include a tenter type stretching machine capable of adding feed forces, pulling forces, or pulling forces at different speeds in the lateral and / or longitudinal directions. The tenter type stretching machine includes a horizontal uniaxial stretching machine, a simultaneous biaxial stretching machine, and the like, but any suitable stretching machine can be used as long as a long resin film can be continuously stretched obliquely.

By appropriately controlling the left and right velocities in the stretching machine, a retardation film having a desired in-plane retardation and having a slow axis in the desired direction (substantially long film) Shaped retardation film) can be obtained.

Examples of the oblique stretching method include, for example, JP-A-50-83482, JP-A-2-113920, JP-A-3-182701, JP-A-2000-9912, JP-A-2002-86554, Examples thereof include the method described in JP-A-2002-22944.

A retardation film (that is, a retardation film having an Nz coefficient of less than 1.0) that can be suitably used in an embodiment of the present invention is a heat-shrinkable film via, for example, an acrylic adhesive on one or both sides of a resin film. Can be manufactured by forming a laminated body and subjecting the laminated body to stretching as described above. A retardation film having a desired Nz coefficient can be obtained by adjusting the configuration of the heat-shrinkable film (for example, shrinkage force) and stretching conditions (for example, stretching temperature).

The stretching temperature of the film can vary depending on the in-plane retardation value and thickness desired for the retardation film, the type of resin used, the thickness of the film used, the stretching ratio, and the like. Specifically, the stretching temperature is preferably Tg-30 ° C to Tg + 30 ° C, more preferably Tg-15 ° C to Tg + 15 ° C, and most preferably Tg-10 ° C to Tg + 10 ° C. By stretching at such a temperature, a retardation film having appropriate characteristics in the present invention can be obtained. Tg is the glass transition temperature of the constituent material of the film.

A commercially available film may be used as the polycarbonate resin film. Specific examples of commercially available products include “Pure Ace WR-S”, “Pure Ace WR-W”, “Pure Ace WR-M” manufactured by Teijin Limited, and “NRF” manufactured by Nitto Denko Corporation. It is done. A commercially available film may be used as it is, and a commercially available film may be used after secondary processing (for example, stretching treatment, surface treatment) depending on the purpose.

A-3. Polarizer Any appropriate polarizer may be adopted as the polarizer. The resin film forming the polarizer may be a single layer resin film or a laminate of two or more layers.

Specific examples of polarizers composed of a single-layer resin film include hydrophilic polymer films such as polyvinyl alcohol (PVA) films, partially formalized PVA films, and ethylene / vinyl acetate copolymer partially saponified films. In addition, there may be mentioned polyene-based oriented films such as those subjected to dyeing treatment and stretching treatment with dichroic substances such as iodine and dichroic dyes, PVA dehydrated products and polyvinyl chloride dehydrochlorinated products. Preferably, a polarizer obtained by dyeing a PVA film with iodine and uniaxially stretching is used because of excellent optical properties.

The dyeing with iodine is performed, for example, by immersing a PVA film in an aqueous iodine solution. The stretching 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. Moreover, you may dye | stain after extending | stretching. If necessary, the PVA film is subjected to swelling treatment, crosslinking treatment, washing treatment, drying treatment and the like. For example, by immersing the PVA film in water and washing it before dyeing, not only can the surface of the PVA film be cleaned of dirt and anti-blocking agents, but the PVA film can be swollen to cause uneven staining. Can be prevented.

As a specific example of a polarizer obtained by using a laminate, a laminate of a resin substrate and a PVA resin layer (PVA resin film) laminated on the resin substrate, or a resin substrate and the resin Examples thereof include a polarizer obtained by using a laminate with a PVA resin layer applied and formed on a substrate. For example, a polarizer obtained by using a laminate of a resin base material and a PVA resin layer applied and formed on the resin base material may be obtained by, for example, applying a PVA resin solution to a resin base material and drying it. A PVA-based resin layer is formed thereon to obtain a laminate of a resin base material and a PVA-based resin layer; the laminate is stretched and dyed to make the PVA-based resin layer a polarizer; obtain. In the present embodiment, stretching typically includes immersing the laminate in an aqueous boric acid solution and stretching. Furthermore, the stretching may further include, if necessary, stretching the laminate in the air at a high temperature (for example, 95 ° C. or higher) before stretching in the aqueous boric acid solution. The obtained resin base material / polarizer laminate may be used as it is (that is, the resin base material may be used as a protective layer of the polarizer), and the resin base material is peeled from the resin base material / polarizer laminate. Any appropriate protective layer according to the purpose may be laminated on the release surface. Details of a method for manufacturing such a polarizer are described in, for example, Japanese Patent Application Laid-Open No. 2012-73580. This publication is incorporated herein by reference in its entirety.

The thickness of the polarizer is preferably 15 μm or less, more preferably 1 μm to 12 μm, still more preferably 3 μm to 10 μm, and particularly preferably 3 μm to 8 μm. When the thickness of the polarizer is in such a range, curling during heating can be satisfactorily suppressed, and good appearance durability during heating can be obtained. Furthermore, if the thickness of the polarizer is in such a range, it can contribute to the reduction in thickness of the image display device.

The polarizer preferably exhibits absorption dichroism at any wavelength between 380 nm and 780 nm. The single transmittance of the polarizer is preferably 43.0% to 46.0%, more preferably 44.5% to 46.0%. The polarization degree of the polarizer is preferably 97.0% or more, more preferably 99.0% or more, and further preferably 99.9% or more.

As described above, a protective film may be disposed on one side or both sides of the polarizer. The protective film is formed of any appropriate film. Specific examples of the material as the main component of the film include cellulose resins such as triacetyl cellulose (TAC), polyester-based, polyvinyl alcohol-based, polycarbonate-based, polyamide-based, polyimide-based, polyethersulfone-based, and polysulfone-based materials. And transparent resins such as polystyrene, polynorbornene, polyolefin, (meth) acryl, and acetate. Further, thermosetting resins such as (meth) acrylic, urethane-based, (meth) acrylurethane-based, epoxy-based, and silicone-based or ultraviolet curable resins are also included. In addition to this, for example, a glassy polymer such as a siloxane polymer is also included. Further, a polymer film described in JP-A-2001-343529 (WO01 / 37007) can also be used. As a material for 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 nitrile group in the side chain For example, a resin composition having an alternating copolymer of isobutene and N-methylmaleimide and an acrylonitrile / styrene copolymer can be mentioned. The polymer film can be, for example, an extruded product of the resin composition.

The thickness of the protective film is preferably 20 μm to 200 μm, more preferably 30 μm to 100 μm, and still more preferably 35 μm to 95 μm.

When a protective film (inner protective film) is disposed on the opposite side of the polarizer from the first retardation layer, the inner protective film is preferably optically isotropic. In this specification, “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.

A-4. Second retardation layer As described above, the in-plane retardation Re (550) of the second retardation layer 50 is 100 nm to 180 nm, preferably 110 nm to 170 nm, more preferably 120 nm to 160 nm, Particularly preferred is 135 nm to 155 nm. If the in-plane retardation of the second retardation layer is in such a range, the retardation that can realize an image display device having excellent antireflection characteristics by being arranged at the specific axis angle as described above. An attached polarizing plate can be obtained.

Furthermore, as described above, the second retardation layer satisfies the relationship of Re (450) <Re (550) <Re (650).

In the second retardation layer, the refractive index ellipsoid as described above has a relationship of nx> ny ≧ nz and has a slow axis. In this case, the slow axis of the first retardation layer 10 and the slow axis of the second retardation layer 50 are substantially orthogonal as described above. With such a configuration, since the dimensional change between the first retardation layer and the second retardation layer becomes a target, curling and the like are suppressed and a polarizing plate with a retardation layer excellent in durability is obtained. Can be. Furthermore, for example, an excellent antireflection function can be realized in an organic EL display device. The Nz coefficient of the second retardation layer is preferably 0.9 to 2, more preferably 1 to 1.5, and still more preferably 1 to 1.3.

Other characteristics, constituent materials, and the like of the second retardation layer are as described in the above section A-2 for the first retardation layer. In addition, regarding the method for forming the second retardation layer, basically, the description in the above section A-2 regarding the first retardation layer can be applied mutatis mutandis. However, the difference is that a heat-shrinkable film is not used during stretching.

As described above, as the second retardation layer, the in-plane retardation Re (550) is 150 nm to 350 nm, satisfies the relationship of Re (450) <Re (550) <Re (650), and has a refractive index. A retardation film whose ellipsoid shows a relationship of nx> nz> ny may be used. That is, the second retardation layer may have the same optical characteristics as the first retardation layer except that the in-plane retardation is different. Such a configuration has an advantage that excellent viewing angle characteristics can be realized, for example, in a liquid crystal display device. In this case, the angle formed by the slow axis of the first retardation layer 10 and the slow axis of the second retardation layer 50 is preferably 35 ° to 55 °, more preferably 38, as described above. It is preferably from 45 ° to 52 °, more preferably from 40 ° to 50 °, particularly preferably from 42 ° to 48 °, particularly preferably from 44 ° to 46 °, and most preferably about 45 °.

A-5. Adhesive Layer Any suitable adhesive can be used as the adhesive constituting the adhesive layer 30. The pressure-sensitive adhesive layer is typically formed of an acrylic pressure-sensitive adhesive. The thickness of the pressure-sensitive adhesive layer is, for example, 10 μm to 50 μm.

A-6. Conductive layer The conductive layer is typically transparent (ie, the conductive layer is a transparent conductive layer). The conductive layer can be patterned as needed. By conducting the patterning, a conductive portion and an insulating portion can be formed. As a result, an electrode can be formed. The electrode can function as a touch sensor electrode that senses contact with the touch panel. The pattern shape is preferably a pattern that works well as a touch panel (for example, a capacitive touch panel). Specific examples include the patterns described in JP2011-511357A, JP2010-164938A, JP2008-310550A, JP2003-511799A, and JP2010-541109A. It is done.

The total light transmittance of the conductive layer is preferably 80% or more, more preferably 85% or more, and further preferably 90% or more. For example, if a conductive nanowire described later is used, a transparent conductive layer having openings can be formed, and a transparent conductive layer having a high light transmittance can be obtained.

The density of the conductive layer is preferably 1.0 g / cm ³ to 10.5 g / cm ³ , more preferably 1.3 g / cm ³ to 3.0 g / cm ³ .

The surface resistance value of the conductive layer is preferably 0.1Ω / □ to 1000Ω / □, more preferably 0.5Ω / □ to 500Ω / □, and further preferably 1Ω / □ to 250Ω / □.

Typical examples of the conductive layer include a conductive layer containing a metal oxide, a conductive layer containing a conductive nanowire, and a conductive layer containing a metal mesh. A conductive layer including conductive nanowires or a conductive layer including a metal mesh is preferable. This is because it is excellent in bending resistance and it is difficult to lose conductivity even when bent, so that a conductive layer that can be bent well can be formed. As a result, the polarizing plate with a retardation layer can be applied to a bendable image display device.

A conductive layer containing a metal oxide is formed on any appropriate base material by any appropriate film formation method (for example, vacuum deposition method, sputtering method, CVD method, ion plating method, spray method, etc.). It can be formed by forming an oxide film. Examples of the metal oxide include indium oxide, tin oxide, zinc oxide, indium-tin composite oxide, tin-antimony composite oxide, zinc-aluminum composite oxide, and indium-zinc composite oxide. Of these, indium-tin composite oxide (ITO) is preferable.

The conductive layer containing conductive nanowires is formed by applying a dispersion liquid (conductive nanowire dispersion liquid) in which conductive nanowires are dispersed in a solvent onto any appropriate substrate, and then drying the coating layer. be able to. Any appropriate conductive nanowire can be used as the conductive nanowire as long as the effects of the present invention can be obtained. The conductive nanowire refers to a conductive substance having a needle shape or a thread shape and a diameter of nanometer size. The conductive nanowire may be linear or curved. As described above, the conductive layer including the conductive nanowire has excellent bending resistance. In addition, a conductive layer containing conductive nanowires can form a good electrical conduction path even with a small amount of conductive nanowires by forming gaps between conductive nanowires and forming a mesh. Thus, a conductive layer having a small electric resistance can be obtained. Further, when the conductive nanowires have a mesh shape, openings can be formed in the mesh gaps to obtain a conductive layer having a high light transmittance. Examples of the conductive nanowire include metal nanowires made of metal, conductive nanowires including carbon nanotubes, and the like.

The ratio between the thickness d and the length L of the conductive nanowire (aspect ratio: L / d) is preferably 10 to 100,000, more preferably 50 to 100,000, still more preferably 100 to 10,000. When conductive nanowires having a large aspect ratio are used in this way, the conductive nanowires can cross well and high conductivity can be expressed by a small amount of conductive nanowires. As a result, a conductive layer having a high light transmittance can be obtained. In this specification, “the thickness of the conductive nanowire” means the diameter when the cross section of the conductive nanowire is circular, and the short diameter when the cross section of the conductive nanowire is elliptical. If it is square, it means the longest diagonal. The thickness and length of the conductive nanowire can be confirmed by a scanning electron microscope or a transmission electron microscope.

The thickness of the conductive nanowire is preferably less than 500 nm, more preferably less than 200 nm, still more preferably 1 nm to 100 nm, and particularly preferably 1 nm to 50 nm. If it is such a range, a conductive layer with high light transmittance can be formed. The length of the conductive nanowire is preferably 2.5 μm to 1000 μm, more preferably 10 μm to 500 μm, and further preferably 20 μm to 100 μm. Within such a range, a conductive layer having high conductivity can be obtained.

As the metal constituting the conductive nanowire (metal nanowire), any appropriate metal can be used as long as it is a highly conductive metal. The metal nanowire is preferably composed of one or more metals selected from the group consisting of gold, platinum, silver, and copper. Among these, silver, copper, or gold is preferable from the viewpoint of conductivity, and silver is more preferable. Alternatively, a material obtained by performing a plating process (for example, a gold plating process) on the metal may be used.

Any appropriate carbon nanotube can be used as the carbon nanotube. For example, so-called multi-walled carbon nanotubes, double-walled carbon nanotubes, single-walled carbon nanotubes and the like are used. Among these, single-walled carbon nanotubes are preferably used because of their high conductivity.

As the metal mesh, any appropriate metal mesh can be used as long as the effects of the present invention can be obtained. For example, it is possible to use a metal wiring layer provided on a film substrate that is patterned in a mesh pattern.

Details of the conductive nanowire and the metal mesh are described in, for example, Japanese Patent Application Laid-Open Nos. 2014-113705 and 2014-219667. The description of the publication is incorporated herein by reference.

The thickness of the conductive layer is preferably 0.01 μm to 10 μm, more preferably 0.05 μm to 3 μm, and still more preferably 0.1 μm to 1 μm. If it is such a range, the conductive layer excellent in electroconductivity and light transmittance can be obtained. When the conductive layer contains a metal oxide, the thickness of the conductive layer is preferably 0.01 μm to 0.05 μm.

The conductive layer is transferred from the substrate on which the conductive layer is formed to the polarizer (or the inner protective film or the second retardation layer, if present), and the conductive layer alone constitutes a polarizing plate with a retardation layer. It may be a layer, and is laminated on a polarizer (or an inner protective film or a second retardation layer, if present) as a laminate (a conductive layer with a substrate) with a substrate, with a retardation layer It may be a constituent layer of a polarizing plate.

B. Image Display Device The long retardation film with retardation layer described in the above section A can be applied to an image display device after being cut into a predetermined size. Therefore, this invention includes the image display apparatus using such a polarizing plate with a phase difference layer. An image display device according to an embodiment of the present invention includes a display cell and a polarizing plate with a retardation layer cut to a predetermined size (that is, a size corresponding to the display cell) on the viewing side. The polarizing plate with a retardation layer is disposed so that the first retardation layer is on the viewing side. Typical examples of the image display device include a liquid crystal display device and an organic EL display device. In one embodiment, the image display device is a liquid crystal display device including a backlight light source having a discontinuous emission spectrum. Hereinafter, such a backlight light source will be described. In addition, about the whole structure of image display apparatuses, such as a liquid crystal display device and an organic electroluminescent display apparatus, since a structure well-known in the industry can be employ | adopted, detailed description is abbreviate | omitted.

The backlight light source is included in the backlight unit of the liquid crystal display device. As described above, the backlight light source has a discontinuous emission spectrum. “Having a discontinuous emission spectrum” means that there is a clear peak in each wavelength region of red (R), green (G), and blue (B), and the respective peaks are clearly distinguished. That means. FIG. 3 is a diagram schematically illustrating an example of a discontinuous emission spectrum. As shown in FIG. 3, the emission spectrum of the backlight light source preferably has a peak P1, preferably 530 nm to 570 nm, more preferably 540 nm in the wavelength region (blue wavelength region) of 430 nm to 470 nm, more preferably 440 nm to 460 nm. It has a peak P2 in the wavelength region of ˜560 nm (green wavelength region), and a peak P3 in the wavelength region of 630 nm to 670 nm, more preferably 640 nm to 660 nm (red wavelength region). Preferably, the wavelength λ1, the height hP1 and the half width Δλ1 of the peak P1, the wavelength λ2, the height hP2 and the half width Δλ2, the wavelength λ3 of the peak P3, the height hP3 and the half width Δλ3, the peak P1 and the peak P2 And the valley height hB2 between the peak P2 and the peak P3 satisfy the following relational expressions (1) to (3):
(Λ2−λ1) / (Δλ2 + Δλ1)> 1 (1)
(Λ3-λ2) / (Δλ3 + Δλ2)> 1 (2)
0.8 ≦ {hP2− (hB2 + hB1) / 2} / hP2 ≦ 1 (3).
(Λ2−λ1) / (Δλ2 + Δλ1) in the formula (1) is more preferably 1.01 to 2.00, and further preferably 1.10 to 1.50. (Λ3-λ2) / (Δλ3 + Δλ2) in the formula (2) is more preferably 1.01 to 2.00, and further preferably 1.10 to 1.50. {HP2- (hB2 + hB1) / 2} in the formula (3) is more preferably 0.85 to 1, and further preferably 0.9 to 1. Equation (1) means that the relationship between blue light and green light is independent as a light source without being mixed. Equation (2) means that the relationship between green light and red light is independent as a light source without being mixed. Equation (3) means that the valleys between the peaks P1, P2 and P3 are low and the peaks of blue light, green light and red light are clearly distinguished. By defining the expressions (1) to (3), there is an advantage that the color reproducibility is improved. Due to the synergistic effect of the backlight source 300 having an emission spectrum satisfying the expressions (1) to (3) and the first retardation layer 200 described above, the color reproducibility is excellent and the polarizing action is achieved. It is possible to realize a liquid crystal display device that is excellent in visibility when visually recognized through an optical member and in which color unevenness is suppressed. For example, an optical having color reproducibility and polarization action as compared with a conventional backlight light source having a light emission spectrum as shown in FIG. 3 (a white light source simply combining LEDs that emit red light, green light and blue light). Visibility and color unevenness when viewed through the member can be significantly improved.

The backlight light source has any suitable configuration capable of realizing the emission spectrum as described above. In one embodiment, the backlight source includes a red color LED, a green color LED, and a blue color LED, and the phosphor of the red color LED is activated with tetravalent manganese ions. ing. By activating the phosphor of the LED that develops red color, the overlap of red light and green light in the emission spectrum shown in FIG. 4 can be reduced, and the emission spectrum as shown in FIG. 3 can be realized. As a preferable specific example of such a red phosphor activated with tetravalent manganese ions, William M. et al. Yen and Marvin J.H. Weber CRC Publishing "INORGANIC PHOSPHORS" p. 212 (SECTION 4: PHOSPHOR DATA 4.10 Miscellaneous Oxides), Mn ⁴⁺ activated Mg fluorogermanate phosphor (2.5MgO · MgF ₂ : Mn ⁴⁺ ) and Journal of the ElectroSocial A: M ¹ ₂ M ² F ₆ : Mn ⁴⁺ (M ¹ = Li, Na, K, Rb, Cs; M ² = Si, Ge, Sn, Ti, Zr, exemplified in SCIENCE AND TECHNOLOGY, July 1973, p942 ) Phosphors. A backlight light source using such a red phosphor is described in, for example, Japanese Patent Application Laid-Open No. 2015-52648. Further, a backlight light source having a general configuration including a red color LED, a green color LED, and a blue color LED is described in, for example, Japanese Patent Application Laid-Open No. 2012-256014. The descriptions in these publications are incorporated herein by reference.

In another embodiment, the backlight source includes a blue color LED and a wavelength conversion layer including quantum dots. With such a configuration, part of the blue light emitted from the LED is converted into red light and green light by the wavelength conversion layer, and part of the blue light is emitted as blue light as it is. As a result, white light can be realized. Furthermore, by appropriately configuring the wavelength conversion layer, a light emission spectrum (light emission spectrum as shown in FIG. 3) in which the peaks of red light, green light, and blue light are clear and the overlap of each color light is small is realized. be able to.

The wavelength conversion layer typically includes a matrix and quantum dots dispersed in the matrix. Any appropriate material can be used as a material constituting the matrix (hereinafter also referred to as matrix material). Examples of such materials include resins, organic oxides, and inorganic oxides. The matrix material preferably has low oxygen permeability and moisture permeability, high light stability and chemical stability, a predetermined refractive index, excellent transparency, and / or Have excellent dispersibility with respect to quantum dots. Considering these comprehensively, the matrix material is preferably a resin. The resin may be a thermoplastic resin, a thermosetting resin, or an active energy ray curable resin (for example, an electron beam curable resin, an ultraviolet curable resin, or a visible light curable resin). May be. A thermosetting resin or an ultraviolet curable resin is preferable, and a thermosetting resin is more preferable. The resins may be used alone or in combination (for example, blend, copolymerization).

Quantum dots can control the wavelength conversion characteristics of the wavelength conversion layer. Specifically, a wavelength conversion layer that realizes light having a desired emission center wavelength can be formed by appropriately combining quantum dots having different emission center wavelengths. The emission center wavelength of the quantum dot can be adjusted by the material and / or composition, particle size, shape, etc. of the quantum dot. Examples of the quantum dot include a quantum dot having an emission center wavelength in a wavelength band in the range of 600 nm to 680 nm (hereinafter referred to as quantum dot A), and a quantum dot having an emission center wavelength in a wavelength band in the range of 500 nm to 600 nm (hereinafter referred to as “dots”). Quantum dots B) and quantum dots having an emission center wavelength in the wavelength band of 400 nm to 500 nm (hereinafter, quantum dots C) are known. The quantum dots A are excited by excitation light (in the present invention, light from a backlight light source) to emit red light, the quantum dots B emit green light, and the quantum dots C emit blue light. By appropriately combining these, when light having a predetermined wavelength (light from the backlight light source) enters and passes through the wavelength conversion layer, light having a light emission center wavelength in a desired wavelength band can be realized.

The quantum dots can be composed of any suitable material. The quantum dots are preferably composed of an inorganic material, more preferably an inorganic conductor material or an inorganic semiconductor material. Semiconductor materials include, for example, II-VI, III-V, IV-VI, and IV semiconductors. Specific examples include Si, Ge, Sn, Se, Te, B, C (including diamond), P, BN, BP, BAs, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, InN, InP, InAs, InSb, ZnO, ZnS, ZnSe, ZnTe, CdS, CdSe, CdSeZn, CdTe, HgS, HgSe, HgTe, BeS, BeSe, BeTe, MgS, MgSe, GeS, GeSe, Sn, Te, SnS PbO, PbS, PbSe, PbTe, CuF, CuCl, CuBr, CuI, Si ₃ N ₄ , Ge ₃ N ₄ , Al ₂ O ₃ , (Al, Ga, In) ₂ (S, Se, Te) ₃ , Al ₂ CO is mentioned. These may be used alone or in combination of two or more. The quantum dot may contain a p-type dopant or an n-type dopant.

Any appropriate size can be adopted as the size of the quantum dot depending on the desired emission wavelength. The size of the quantum dots is preferably 1 nm to 10 nm, more preferably 2 nm to 8 nm. If the size of the quantum dot is in such a range, each of green and red emits sharp light and high color rendering can be realized. For example, green light can be emitted with a quantum dot size of about 7 nm, and red light can be emitted with about 3 nm. The size of the quantum dot is, for example, an average particle diameter when the quantum dot is a true sphere, and is a dimension along the minimum axis in the shape when the quantum dot is other than that. As the shape of the quantum dot, any appropriate shape can be adopted depending on the purpose. Specific examples include a true sphere shape, a flake shape, a plate shape, an elliptic sphere shape, and an indefinite shape.

Quantum dots can be blended in a proportion of preferably 1 to 50 parts by weight, more preferably 2 to 30 parts by weight, with respect to 100 parts by weight of the matrix material. When the blending amount of the quantum dots is in such a range, a liquid crystal display device excellent in hue balance of all RGB can be realized.

Details of the quantum dots are disclosed in, for example, JP2012-169271A, JP2015-102857A, JP2015-65158A, JP2013-544018A, JP2013-544018A, Special Table. No. 2010-533976, and the descriptions of these publications are incorporated herein by reference. A commercial item may be used for the quantum dot.

The thickness of the wavelength conversion layer is preferably 1 μm to 500 μm, more preferably 100 μm to 400 μm. When the thickness of the wavelength conversion layer is in such a range, conversion efficiency and durability can be excellent.

The wavelength conversion layer is disposed as a film on the emission side of the LED (light source) in the backlight unit.

Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to these examples. In addition, the measuring method of each characteristic is as follows. Unless otherwise specified, “parts” and “%” in the examples are based on weight.

(1) Thickness The thickness was measured using a dial gauge (manufactured by PEACOCK, product name “DG-205”, dial gauge stand (product name “pds-2”)).
(2) Retardation A 50 mm × 50 mm sample was cut out from each retardation film and the liquid crystal solidified layer to obtain a measurement sample, which was measured using Axoscan manufactured by Axometrics. The measurement wavelength was 450 nm, 550 nm, and the measurement temperature was 23 ° C.
Moreover, the average refractive index was measured using an Abbe refractometer manufactured by Atago Co., Ltd., and the refractive indexes nx, ny, and nz were calculated from the obtained retardation values.
(3) Water absorption rate Measured according to “Test method for water absorption rate and boiling water absorption rate of plastic” described in JIS K 7209. The size of the test piece was a square with a side of 50 mm, and was obtained by immersing the test piece in water at a water temperature of 25 ° C. for 24 hours and then measuring the weight change before and after the immersion. The unit is%.
(4) Backlight spectrum measurement A white image was displayed on the liquid crystal display device obtained in Example 2, and an emission spectrum was measured using SR-UL1R manufactured by Topcon. For the obtained emission spectrum, wavelength λ1, wavelength λ2, wavelength λ3, height hP1, height hP2, height hP3, height hB1, height hB2, half width Δλ1, half width Δλ2, and half width shown in FIG. Based on the value width Δλ3, a light source having a discontinuous spectrum was satisfied that satisfies the following equations (1) to (3). Since the spectrum of the display light when the white image is displayed on the liquid crystal display device is substantially equal to the emission spectrum of the backlight light source, the spectrum of the display light when the white image is displayed is the emission spectrum of the backlight light source. It was.
(Λ2−λ1) / (Δλ2 + Δλ1)> 1 (1)
(Λ3-λ2) / (Δλ3 + Δλ2)> 1 (2)
0.8 ≦ {hP2- (hB2 + hB1) / 2} / hP2 ≦ 1 (3)
(5) Visibility evaluation A white image was displayed on the display device obtained in each example and each comparative example, and the visibility when the image was observed through polarized sunglasses was evaluated according to the following criteria.
Good: Coloring and rainbow unevenness did not occur. Coloring occurred.

<Example 1>
(Preparation of retardation film A constituting the first retardation layer)
Polymerization was carried out using a batch polymerization apparatus comprising two vertical reactors equipped with a stirring blade and a reflux condenser controlled at 100 ° C. 9,9- [4- (2-hydroxyethoxy) phenyl] fluorene (BHEPF), isosorbide (ISB), diethylene glycol (DEG), diphenyl carbonate (DPC), and magnesium acetate tetrahydrate in a molar ratio of BHEPF / ISB / DEG / DPC / magnesium acetate = 0.348 / 0.490 / 0.162 / 1.005 / 1.00 × 10 ⁻⁵ . After sufficiently replacing the inside of the reactor with nitrogen (oxygen concentration 0.0005 to 0.001 vol%), heating was performed with a heating medium, and stirring was started when the internal temperature reached 100 ° C. After 40 minutes from the start of temperature increase, the internal temperature was reached to 220 ° C., and control was performed so as to maintain this temperature. The phenol vapor produced as a by-product with the polymerization reaction was led to a reflux condenser at 100 ° C., and a monomer component contained in a small amount in the phenol vapor was returned to the reactor, and the phenol vapor not condensed was led to a condenser at 45 ° C. and recovered.
Nitrogen was introduced into the first reactor and the pressure was once restored to atmospheric pressure, and then the oligomerized reaction liquid in the first reactor was transferred to the second reactor. Subsequently, the temperature increase and pressure reduction in the second reactor were started, and the internal temperature was 240 ° C. and the pressure was 0.2 kPa in 50 minutes. Thereafter, polymerization was allowed to proceed until a predetermined stirring power was obtained. When a predetermined power is reached, nitrogen is introduced into the reactor, the pressure is restored, the reaction solution is withdrawn in the form of a strand, pelletized with a rotary cutter, and BHEPF / ISB / DEG = 34.8 / 49.0 / A polycarbonate resin having a copolymer composition of 16.2 [mol%] was obtained. This polycarbonate resin had a reduced viscosity of 0.430 dL / g and a glass transition temperature of 128 ° C.
The obtained polycarbonate resin was dissolved in methylene chloride to prepare a birefringent layer forming material. Next, the birefringent layer-forming material was directly coated on a shrinkable film (longitudinal uniaxially stretched polypropylene film, trade name “Noblen” manufactured by Tokyo Ink Co., Ltd.), and the coating film was dried at 30 ° C. at 5 ° C. The laminate was dried for 5 minutes at 80 ° C. for 5 minutes to form a laminate (60 μm) of a shrinkable film / birefringent layer.
The obtained laminate was preheated to 142 ° C. in the preheating zone of the stretching apparatus. In the preheating zone, the clip pitch of the left and right clips was 125 mm. Next, as soon as the film entered the first oblique stretching zone C1, the clip pitch of the right clip began to increase and increased from 125 mm to 177.5 mm in the first oblique stretching zone C1. The clip pitch change rate was 1.42. In the first oblique stretching zone C1, the clip pitch of the left clip started to decrease and decreased from 125 mm to 90 mm in the first oblique stretching zone C1. The clip pitch change rate was 0.72. Furthermore, as soon as the film entered the second oblique stretching zone C2, the clip pitch of the left clip started to increase and increased from 90 mm to 177.5 mm in the second oblique stretching zone C2. On the other hand, the clip pitch of the right clip was maintained at 177.5 mm in the second oblique stretching zone C2. Simultaneously with the above oblique stretching, the film was stretched 1.7 times in the width direction. The oblique stretching was performed at 135 ° C. Next, MD shrinkage treatment was performed in the shrinkage zone. Specifically, both the clip pitches of the left clip and the right clip were reduced from 177.5 mm to 160 mm. The shrinkage rate in the MD shrinkage treatment was 10.0%. The retardation film A was formed on the shrinkable film by the above stretching treatment. Next, the retardation film A was peeled from the shrinkable film.
Thus, a retardation film A (thickness 60 μm) was obtained. Re (550) of the obtained retardation film A was 140 nm, Rth (550) was 70 nm, and Re (450) / Re (550) was 0.89. The slow axis direction of the retardation film A was 135 ° with respect to the longitudinal direction.

(Production of polarizer)
An A-PET (amorphous-polyethylene terephthalate) film (manufactured by Mitsubishi Plastics Co., Ltd., trade name: Novaclear SH046 200 μm) was prepared as a base material, and the surface was subjected to corona treatment (58 W / m ² / min). On the other hand, 1 wt% of acetoacetyl-modified PVA (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name: Gohsephimer Z200 (polymerization degree 1200, saponification degree 99.0% or more, acetoacetyl modification degree 4.6%)) is added. Prepared PVA (polymerization degree 4200, saponification degree 99.2%), coated on a substrate so that the film thickness after drying becomes 12 μm, and dried for 10 minutes by hot air drying in an atmosphere of 60 ° C. And the laminated body which provided the layer of the PVA-type resin on the base material was produced.
Next, the laminate was first stretched 2.0 times in the MD direction at 130 ° C. in air to produce a stretched laminate. Next, a step of insolubilizing the PVA layer in which the PVA molecules contained in the stretched laminate were oriented was performed by immersing the stretched laminate in a boric acid insolubilized aqueous solution having a liquid temperature of 30 ° C. for 30 seconds. The boric acid aqueous solution for insolubilization in this step contains 3 parts by weight of boric acid content with respect to 100 parts by weight of water. A colored laminate was produced by dyeing the stretched laminate after the insolubilization step. In this colored laminate, iodine is adsorbed on the PVA layer contained in the stretched laminate by immersing the stretched laminate in a dyeing solution. The staining solution contains iodine and potassium iodide, the temperature of the staining solution is 30 ° C., water is used as a solvent, the iodine concentration is in the range of 0.08 to 0.25 wt%, and the potassium iodide concentration Was in the range of 0.56 to 1.75% by weight. The ratio of iodine to potassium iodide concentration was 1: 7. As dyeing conditions, the iodine concentration and the immersion time were set so that the single transmittance of the PVA resin layer constituting the polarizer was 40.9%.
Next, the colored laminate was immersed in an aqueous boric acid solution for crosslinking at 30 ° C. for 60 seconds to perform a step of crosslinking the PVA molecules of the PVA layer on which iodine was adsorbed. The boric acid aqueous solution for crosslinking used in this crosslinking step had a boric acid content of 3 parts by weight with respect to 100 parts by weight of water and a potassium iodide content of 3 parts by weight with respect to 100 parts by weight of water. Is. Further, the obtained colored laminate is stretched 2.7 times in a boric acid aqueous solution at a stretching temperature of 70 ° C. in the same direction as the previous stretching in air, whereby the final stretching ratio is increased. The film was stretched by 5.4 times to obtain an optical film laminate including the test polarizer. The boric acid aqueous solution used in this stretching step has a boric acid content of 4.0 parts by weight with respect to 100 parts by weight of water and a potassium iodide content of 5 parts by weight with respect to 100 parts by weight of water. It is. The obtained optical film laminate was taken out from the boric acid aqueous solution, and the boric acid adhering to the surface of the PVA layer was washed with an aqueous solution containing 4 parts by weight of potassium iodide with respect to 100 parts by weight of water. The washed optical film laminate was dried by a drying process using hot air at 60 ° C. to obtain a long polarizer having an absorption axis in the longitudinal direction and having a thickness of 5 μm laminated on the PET film.

(Preparation of retardation film B constituting the second retardation layer)
A polycarbonate resin was obtained by the same method as the method for obtaining the polycarbonate resin in the production of the retardation film A. The obtained polycarbonate resin was vacuum-dried at 80 ° C. for 5 hours, and then a single-screw extruder (manufactured by Isuzu Chemical Industries, screw diameter 25 mm, cylinder set temperature: 220 ° C.), T-die (width 900 mm, set temperature: 220). ° C), a chill roll (set temperature: 125 ° C), and a film-forming apparatus equipped with a winder, a polycarbonate resin film having a thickness of 130 µm was produced. The polycarbonate resin film obtained had a water absorption rate of 1.2%.
The polycarbonate resin film was obliquely stretched by a method according to Example 1 of JP 2014-194383 A to obtain a retardation film B.
A specific production procedure of the retardation film B is as follows: A polycarbonate resin film (thickness 130 μm, width 765 mm) was preheated to 142 ° C. in a preheating zone of a stretching apparatus. In the preheating zone, the clip pitch of the left and right clips was 125 mm. Next, as soon as the film entered the first oblique stretching zone C1, the clip pitch of the right clip began to increase and increased from 125 mm to 177.5 mm in the first oblique stretching zone C1. The clip pitch change rate was 1.42. In the first oblique stretching zone C1, the clip pitch of the left clip started to decrease and decreased from 125 mm to 90 mm in the first oblique stretching zone C1. The clip pitch change rate was 0.72. Furthermore, as soon as the film entered the second oblique stretching zone C2, the clip pitch of the left clip started to increase and increased from 90 mm to 177.5 mm in the second oblique stretching zone C2. On the other hand, the clip pitch of the right clip was maintained at 177.5 mm in the second oblique stretching zone C2. Simultaneously with the oblique stretching, stretching in the width direction was performed 1.9 times. The oblique stretching was performed at 135 ° C. Next, MD shrinkage treatment was performed in the shrinkage zone. Specifically, the clip pitches of the left clip and right clip were both reduced from 177.5 mm to 165 mm. The shrinkage rate in the MD shrinkage treatment was 7.0%.
Thus, a retardation film B (thickness 40 μm) was obtained. Re (550) of the obtained retardation film B was 140 nm, Rth (550) was 168 nm, and Re (450) / Re (550) was 0.89. The slow axis direction of the retardation film B was 45 ° with respect to the longitudinal direction.

(Preparation of polarizing plate with retardation layer)
In the polarizer produced as described above, the retardation film A is attached to the surface opposite to the PET with a UV curable adhesive on the 5 μm thick polarizer laminated on the PET film. Bonding was performed so that the angle formed by the slow axis and the absorption axis of the polarizer was substantially 135 °. Further, after peeling the PET film from this laminate, the retardation film B is placed on the surface opposite to the retardation film A of the polarizer via a UV curable adhesive, with the slow axis and the above-mentioned position. The film was laminated so that the slow axis of the retardation film A was substantially orthogonal to produce a long retardation film with a retardation layer.

(Production of organic EL display device)
A pressure-sensitive adhesive layer was formed with an acrylic pressure-sensitive adhesive on the retardation film B side of the obtained polarizing plate with a retardation layer, and cut into dimensions of 50 mm × 50 mm.
The smartphone (Galaxy-S5 manufactured by Samsung Radio Co., Ltd.) was disassembled and the organic EL panel of the organic EL display device was taken out. The polarizing film attached to the organic EL panel was peeled off, and instead the polarizing plate with a retardation layer cut out to 50 mm × 50 mm was attached via the adhesive layer to obtain an organic EL panel. . The organic EL panel on which the polarizing plate with a retardation plate was bonded was attached to the smartphone to obtain the organic EL display device of this example. A white image was displayed on the organic EL display device, and the visibility was evaluated through polarized sunglasses in a white image state. The evaluation results are shown in Table 1.

<Example 2>
(Preparation of retardation film C constituting the second retardation layer)
In a reaction vessel equipped with a stirrer, 27.0 kg of 2,2-bis (4-hydroxyphenyl) -4-methylpentane and 0.8 kg of tetrabutylammonium chloride were dissolved in 250 L of sodium hydroxide solution. To this solution, a solution prepared by dissolving 13.5 kg of terephthalic acid chloride and 6.30 kg of isophthalic acid chloride in 300 L of toluene was added at a time while stirring, and stirred at room temperature for 90 minutes to obtain a polycondensation solution. Thereafter, the polycondensation solution was allowed to stand and separate to separate a toluene solution containing polyarylate. Next, the separation liquid was washed with acetic acid water and further washed with ion exchange water, and then poured into methanol to precipitate polyarylate. The precipitated polyarylate was filtered and dried under reduced pressure to obtain 34.1 kg of white polyarylate (yield 92%).
10 kg of the resulting polyarylate was dissolved in 73 kg of toluene to prepare a coating solution. Thereafter, the coating solution is directly applied onto a shrinkable film (longitudinal uniaxially stretched polypropylene film, manufactured by Tokyo Ink Co., Ltd., trade name “Noblen”), and the coating film is dried at a temperature of 60 ° C. for 5 minutes. And dried at 80 ° C. for 5 minutes to form a shrinkable film / birefringent layer laminate. The obtained laminate is stretched at a stretching temperature of 155 ° C. at a stretching temperature of 155 ° C. and stretched at a shrinkage ratio of 0.80 in the MD direction and 1.17 times in the TD direction, whereby a retardation film C is formed on the shrinkable film. Formed. Subsequently, the retardation film C was peeled from the shrinkable film. The thickness of the retardation film C was 17 μm, Re (550) was 270 nm, Rth (550) was 135 nm, Re (450) / Re (550) was 1.10, and the Nz coefficient was 0.50. The slow axis direction of the retardation film C was 90 ° with respect to the longitudinal direction.

(Preparation of polarizing plate with retardation layer)
The retardation film A was bonded so that the angle formed between the slow axis and the absorption axis of the polarizer was substantially 45 °, and the retardation film C was used instead of the retardation film B. The angle between the retardation axis of the retardation film C and the retardation axis of the retardation film A is substantially 45 °, and the retardation axis of the retardation film C and the absorption axis of the polarizer are A polarizing plate with a retardation layer was produced in the same manner as in Example 1 except that they were bonded so as to be substantially orthogonal.

(Production of liquid crystal display device)
Take out the liquid crystal panel from the liquid crystal display device of the smartphone (SONY Xperia Z4: the backlight emission spectrum is discontinuous) equipped with an IPS liquid crystal display device, remove the polarizing plate placed on the viewing side of the liquid crystal cell, The glass surface of the liquid crystal cell was washed. Subsequently, on the surface on the viewing side of the liquid crystal cell, the surface on the phase difference film C side of the polarizing plate with the retardation plate, so that the absorption axis of the polarizer is orthogonal to the initial alignment direction of the liquid crystal cell, A liquid crystal panel was obtained by laminating with an acrylic adhesive (thickness 20 μm). The liquid crystal panel on which the polarizing plate with a retardation plate was laminated was attached to the smartphone to obtain the liquid crystal display device of this example. A white image was displayed on the liquid crystal display device, and the visibility was evaluated through polarized sunglasses in a white image state. The evaluation results are shown in Table 1.

<Comparative Example 1>
(Preparation of retardation film D constituting first retardation layer)
A retardation film D was obtained by stretching a commercially available Arton film (manufactured by JSR Corporation, thickness 70 μm). Re (550) of the obtained retardation film D was 140 nm, Rth (550) was 168 nm, and Re (450) / Re (550) was 1.00. The slow axis direction of the retardation film D was 135 ° with respect to the longitudinal direction.

(Preparation of polarizing plate with retardation layer)
The retardation film D was used in place of the retardation film A, and the retardation film B was bonded so that the angle between the slow axis and the absorption axis of the polarizer was substantially 45 °. A polarizing plate with a retardation layer was produced in the same manner as in Example 1 except that the slow axis and the slow axis of the retardation film D were bonded so as to be substantially perpendicular to each other.

(Production of organic EL display device)
An organic EL display device was produced in the same manner as in Example 1 except that the above polarizing plate with retardation layer was used. A white image was displayed on the organic EL display device, and the visibility was evaluated through polarized sunglasses in a white image state. The evaluation results are shown in Table 1.

<Comparative Example 2>
(Preparation of retardation film E constituting the first retardation layer)
Phosgene as the carbonate precursor, (A) 2,2-bis (4-hydroxyphenyl) propane as the aromatic dihydric phenol component, and (B) 1,1-bis (4-hydroxyphenyl) -3,3,5- Using trimethylcyclohexane, the repeating unit of the following chemical formulas (I) and (II) having a weight ratio of (A) :( B) of 4: 6 and a weight average molecular weight (Mw) of 60,000 according to a conventional method Polycarbonate resin [number average molecular weight (Mn) = 33,000, Mw / Mn = 1.78] was obtained. 70 parts by weight of the above polycarbonate resin and 30 parts by weight of a styrene resin having a weight average molecular weight (Mw) of 1,300 [number average molecular weight (Mn) = 716, Mw / Mn = 1.78] (Sanyo Kasei Heimer SB75) Was added to 300 parts by weight of dichloromethane and stirred and mixed at room temperature for 4 hours to obtain a transparent solution. This solution was cast on a glass plate and allowed to stand at room temperature for 15 minutes, then peeled off from the glass plate, dried in an oven at 80 ° C. for 10 minutes, and then at 120 ° C. for 20 minutes, and had a thickness of 40 μm and a glass transition temperature (Tg ) Obtained a polymer film of 140 ° C. The polymer film obtained had a light transmittance of 93% at a wavelength of 590 nm. The in-plane retardation value of the polymer film: Re (590) was 5.0 nm, and the retardation value in the thickness direction: Rth (590) was 12.0 nm. The average refractive index was 1.576.
A retardation film E was obtained by stretching the obtained polymer film. Re (550) of the obtained retardation film E was 140 nm, Rth (550) was 168 nm, and Re (450) / Re (550) was 1.06. The slow axis direction of the retardation film E was 135 ° with respect to the longitudinal direction.

(Preparation of polarizing plate with retardation layer)
The retardation film E was used in place of the retardation film A, and the retardation film B was bonded so that the angle between the slow axis and the absorption axis of the polarizer was substantially 45 °. A polarizing plate with a retardation layer was produced in the same manner as in Example 1 except that the slow axis and the slow axis of the retardation film E were bonded so as to be substantially perpendicular to each other.

The polarizing plate with a retardation layer of the present invention can be suitably used for image display devices such as liquid crystal display devices and organic EL display devices.

DESCRIPTION OF SYMBOLS 10 1st phase difference layer 20 Polarizer 30 Adhesive layer 40 Separator 50 2nd phase difference layer 100 Polarizing plate 101 with phase difference layer Polarizing plate with phase difference layer

Claims

Long,
A retardation layer, a polarizer, and an adhesive layer are provided in this order,
The in-plane retardation Re (550) of the retardation layer is 100 nm to 180 nm, satisfies the relationship of Re (450) <Re (550) <Re (650), and the refractive index ellipsoid of the retardation layer Indicates a relationship of nx>nz> ny, and the Nz coefficient is 0.2 to 0.8.
Polarizing plate with retardation layer.
The polarizing plate with a retardation layer according to claim 1, wherein an angle formed between a slow axis of the retardation layer and an absorption axis of the polarizer is 125 ° to 145 °.
Further comprising another retardation layer between the polarizer and the pressure-sensitive adhesive layer,
The in-plane retardation Re (550) of the other retardation layer is 100 nm to 180 nm, and the refractive index ellipsoid of the other retardation layer shows a relationship of nx> ny ≧ nz.
The polarizing plate with a retardation layer according to claim 1.
Further comprising another retardation layer between the polarizer and the pressure-sensitive adhesive layer,
The in-plane retardation Re (550) of the other retardation layer is 150 nm to 350 nm, and the refractive index ellipsoid of the other retardation layer shows a relationship of nx>nz> ny.
The polarizing plate with a retardation layer according to claim 1.
The polarizing plate with a retardation layer according to claim 3, wherein a slow axis of the retardation layer and a slow axis of the other retardation layer are substantially perpendicular to each other.
The polarizing plate with a retardation layer according to claim 4, wherein an angle formed between the slow axis of the retardation layer and the slow axis of the other retardation layer is 35 ° to 55 °.
The polarizing plate with a retardation layer according to claim 5 or 6, wherein an in-plane retardation of the other retardation layer satisfies a relationship of Re (450) <Re (550) <Re (650).
The polarizing plate with a retardation layer according to any one of claims 1 to 7, wherein a separator is temporarily attached to the outside of the pressure-sensitive adhesive layer.
The polarizing plate with a retardation layer according to claim 1, which is in a roll shape.
An image display device comprising the cut polarizing plate with a retardation layer according to claim 1 on the viewing side, wherein the retardation layer of the polarizing plate with the retardation layer is disposed on the viewing side.
The image display device according to claim 10, which is a liquid crystal display device or an organic electroluminescence display device provided with a backlight source having a discontinuous emission spectrum.