CN117242374A

CN117242374A - Polarizing plate with retardation layer, method for producing same, and image display device using polarizing plate with retardation layer

Info

Publication number: CN117242374A
Application number: CN202280022202.9A
Authority: CN
Inventors: 林大辅; 菅野亮
Original assignee: Nitto Denko Corp
Current assignee: Nitto Denko Corp
Priority date: 2021-03-22
Filing date: 2022-02-07
Publication date: 2023-12-15
Also published as: KR20230145479A; JP2022146118A; WO2022201907A1; TW202248691A

Abstract

The invention provides a polarizing plate with a phase difference layer, which can realize an image display device with suppressed reflection hue change under high temperature environment. The polarizing plate with a retardation layer according to an embodiment of the present invention includes: a polarizing plate including a polarizer and a protective layer disposed on at least one side of the polarizer; a first retardation layer disposed on the opposite side of the polarizing plate from the viewing side; and a second phase difference layer bonded to the opposite side of the first phase difference layer from the polarizing plate via an adhesive layer. The first retardation layer is a retardation layer other than the C plate, and the second retardation layer is the C plate. In one embodiment, the adhesive layer includes an active energy ray-curable adhesive, and the curing shrinkage of the adhesive is 5% or more. In another embodiment, the laminate of the first phase difference layer and the second phase difference layer is annealed.

Description

Polarizing plate with retardation layer, method for producing same, and image display device using polarizing plate with retardation layer

Technical Field

The present invention relates to a polarizing plate with a retardation layer, a method for producing the same, and an image display device using the polarizing plate with a retardation layer.

Background

In recent years, image display devices typified by liquid crystal display devices and Electroluminescence (EL) display devices (for example, organic EL display devices and inorganic EL display devices) have been rapidly spreading. In an image display device, a polarizing plate and a phase difference plate are typically used. In terms of practicality, a polarizing plate with a retardation layer, which is formed by integrating a polarizing plate and a retardation plate, is widely used, but recently, demands for thinning of an image display device are increasing, and accordingly, demands for thinning of a polarizing plate with a retardation layer are increasing. As one method for coping with the thinning of a polarizing plate with a retardation layer, a polarizing plate with a retardation layer using a retardation layer in which a liquid crystal compound is fixed in an aligned state has been proposed. However, an image display device using such a polarizing plate with a retardation layer has a problem in that the reflected color phase changes greatly in a high-temperature environment.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open No. 2020-064274

Disclosure of Invention

Problems to be solved by the invention

The present invention has been made to solve the above-described problems, and a main object of the present invention is to provide a polarizing plate with a retardation layer for an image display device capable of suppressing a change in reflection hue in a high-temperature environment.

Means for solving the problems

The polarizing plate with a retardation layer according to an embodiment of the present invention includes: a polarizing plate including a polarizer and a protective layer disposed on at least one side of the polarizer; a first retardation layer disposed on the opposite side of the polarizing plate from the viewing side (which may also be referred to as "viewing side"); and a second phase difference layer bonded to the opposite side of the first phase difference layer from the polarizing plate via an adhesive layer. The first retardation layer is a retardation layer other than a C plate, and the second retardation layer is a C plate. In one embodiment, the adhesive layer includes an active energy ray-curable adhesive having a cure shrinkage of 5% or more. In another embodiment, the laminate of the first phase difference layer and the second phase difference layer is annealed.

In one embodiment, the first retardation layer exhibits refractive index characteristics such that nx > ny.gtoreq.nz, re (550) is 100nm to 200nm, and satisfies Re (450) < Re (550); the second phase difference layer exhibits refractive index characteristics of nz > nx=ny. Re (450) and Re (550) are in-plane retardation measured at 23℃by light having wavelengths of 450nm and 550nm, respectively.

In one embodiment, the first phase difference layer and the second phase difference layer are alignment cured layers of a liquid crystal compound.

According to another aspect of the present invention, there is provided a method for producing the polarizing plate with a retardation layer. The manufacturing method comprises the following steps: forming the first phase difference layer on a first substrate; forming the second phase difference layer on a second substrate; and bonding the first retardation layer of the laminate of the first base material and the first retardation layer to the second retardation layer of the laminate of the second base material and the second retardation layer via an active energy ray-curable adhesive, thereby forming an intermediate laminate.

In one embodiment, the active energy ray-curable adhesive has a cure shrinkage of 5% or more. In this case, the manufacturing method includes: when forming the intermediate laminate, re (550) of the first retardation layer is increased by 0.5nm or more.

In another embodiment, the above-described method of manufacturing further comprises annealing the intermediate laminate. In this case, the manufacturing method includes: re (550) of the first retardation layer is increased by 0.5nm or more by the annealing treatment. In one embodiment, the annealing treatment is performed at a treatment temperature of 80 ℃ or higher and for a treatment time of 1 minute or longer.

According to still another aspect of the present invention, there is provided an image display apparatus. The image display device includes the polarizing plate with a retardation layer.

Effects of the invention

According to the embodiment of the present invention, a polarizing plate with a retardation layer capable of realizing an image display device in which a change in reflection hue under a high-temperature environment is suppressed can be obtained.

Drawings

Fig. 1 is a schematic cross-sectional view of a polarizing plate with a retardation layer according to an embodiment of the present invention.

Fig. 2 is a flowchart including a schematic cross-sectional view for explaining a process of manufacturing a polarizing plate with a retardation layer according to an embodiment of the present invention.

Detailed Description

Hereinafter, 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 the present specification are as follows.

(1) Refractive index (nx, ny, nz)

"nx" is a refractive index in a direction in which the refractive index in the plane reaches the maximum (i.e., the slow axis direction), "ny" is a refractive index in a direction orthogonal to the slow axis in the plane (i.e., the fast axis direction), and "nz" is a refractive index in the thickness direction.

(2) In-plane phase difference (Re)

"Re (λ)" is the in-plane retardation obtained by measurement at 23℃with light having a wavelength of λ nm. For example, "Re (550)" is the in-plane retardation obtained by measurement with light having a wavelength of 550nm at 23 ℃. Re (λ) is represented by the formula: re (λ) = (nx-ny) ×d.

(3) Retardation in thickness direction (Rth)

"Rth (λ)" is a phase difference in the thickness direction measured at 23℃by light having a wavelength of λ nm. For example, "Rth (550)" is a phase difference in the thickness direction measured at 23℃with light having a wavelength of 550 nm. Rth (λ) is represented by the formula: rth (λ) = (nx-nz) ×d.

(4) Nz coefficient

The Nz coefficient is obtained by nz=rth/Re.

(5) Angle of

In the present specification, when referring to an angle, the angle includes both a clockwise direction and a counterclockwise direction with respect to a reference direction. Thus, for example, "45" means ± 45 °.

A. Integral structure of polarizing plate with phase difference layer

Fig. 1 is a schematic cross-sectional view of a polarizing plate with a retardation layer according to an embodiment of the present invention. The polarizing plate 100 with a retardation layer illustrated in the drawing typically has a polarizing plate 10, a first retardation layer 21, and a second retardation layer 22 in this order from the viewing side. The polarizing plate 10 includes a polarizer 11 and a protective layer disposed on at least one side of the polarizer 11. In the illustrated example, the protective layers (the visible side protective layer 12 and the inner protective layer 13) are disposed on both sides of the polarizer 11, but one of the visible side protective layer 12 and the inner protective layer 13 may be omitted depending on the purpose or the like. The first retardation layer 21 is typically bonded to the opposite side of the polarizing plate 10 from the viewing side via the 1 st adhesive layer 40. The second retardation layer 22 is bonded to the first retardation layer 21 on the opposite side of the polarizing plate 10 via the adhesive layer 30.

In the embodiment of the present invention, the first phase difference layer 21 is a phase difference layer other than a C plate, and the second phase difference layer 22 is a C plate. The first retardation layer 21 typically exhibits refractive index characteristics of nx > ny.gtoreq.nz. That is, the first retardation layer may be a positive a plate (nx > ny=nz) or a negative B plate (nx > ny > nz). Further, re (550) of the first retardation layer is preferably 100nm to 200nm, and it is preferable that Re (450) < Re (550) is satisfied. The second phase difference layer 22 typically exhibits refractive index characteristics of nz > nx=ny. That is, the second phase difference layer may be a positive C plate. If the first phase difference layer and the second phase difference layer are configured as described above, a polarizing plate with a phase difference layer having excellent antireflection characteristics can be realized.

The first phase difference layer and the second phase difference layer are typically alignment cured layers of liquid crystal compounds (hereinafter, may be simply referred to as liquid crystal alignment cured layers). By using a liquid crystal compound, the difference between nx and ny of the obtained retardation layer can be significantly increased as compared with a non-liquid crystal material, and thus the thickness of the first retardation layer for obtaining a desired in-plane retardation can be significantly reduced. In addition, the second phase difference layer (positive C plate) can be formed with a very thin thickness. As a result, the polarizing plate with the retardation layer can be further thinned. The term "alignment cured layer" as used herein refers to a layer in which a liquid crystal compound is aligned in a specific direction within the layer and the alignment state thereof is fixed. The term "alignment cured layer" is a concept including an alignment cured layer obtained by curing a liquid crystal monomer. The first retardation layer is typically oriented (horizontally oriented) with the rod-like liquid crystal compound aligned in the slow axis direction of the retardation layer; the second phase difference layer is typically oriented with the rod-like liquid crystal compound perpendicular to the film surface (homeotropic alignment).

In the embodiment of the present invention, the adhesive layer 30 contains an active energy ray-curable adhesive. The cure shrinkage of the adhesive is typically 5% or more. Further, the laminate of the first retardation layer and the second retardation layer is typically subjected to an annealing treatment. With the above configuration, re (550) of the laminate of the first phase difference layer and the second phase difference layer (substantially the first phase difference layer) can be increased as compared with the case where the curing shrinkage rate of the adhesive is small and/or the case where the laminate of the first phase difference layer and the second phase difference layer is not annealed. As a result, the front reflection color phase a and b values at the initial stage (before being placed in a high-temperature environment) of the image display device can be set at L ^* a ^* b ^* The chromaticity diagram in the color space is shifted in advance in the direction of change in the high-temperature environment. Therefore, the change Δa of the reflected hue under a high-temperature environment (for example, after a endurance test) can be reduced ^* b ^* . Such an effect is remarkable when the retardation layer is a liquid crystal alignment cured layer. That is, the liquid crystal alignment cured layer is susceptible to dimensional shrinkage of the polarizing plate under a high temperature environment, and there is a phase difference layer compared with the resin filmChange Δa in reflected hue ^* b ^* And a greater tendency. Here, by shifting the initial front reflection hue a value and b value in advance in the direction of change in the high-temperature environment (by the influence of the previously-subjected dimensional shrinkage) as described above, the influence of the dimensional shrinkage of the polarizing plate in the high-temperature environment can be reduced, and as a result, the reflection hue change Δa can be reduced ^* b ^* 。

In terms of practicality, the second adhesive layer is provided on the second retardation layer 22 on the opposite side to the polarizing plate 10 (i.e., as the outermost layer on the opposite side to the visible side), so that the polarizing plate with the retardation layer can be attached to the image display panel. Further, it is preferable that: a release film (not shown) is temporarily adhered to the surface of the second adhesive layer 50 until the polarizing plate with the retardation layer is used. By temporarily adhering the release film, the second adhesive layer 50 can be protected, and the polarizing plate with the retardation layer can be wound and formed into a roll.

The total thickness of the polarizing plate with the retardation layer is preferably 120 μm or less, more preferably 100 μm or less, and still more preferably 80 μm or less. The lower limit of the total thickness may be 45 μm, for example. The polarizing plate with a retardation layer having the above total thickness can have extremely excellent flexibility and bending durability. As a result, the polarizing plate with the retardation layer can be suitably applied particularly to a curved image display device and/or an image display device that can be curved or bent. The total thickness of the polarizing plate with the retardation layer is the total thickness from the visible side protective layer 12 (where present) to the second retardation layer 22. That is, the total thickness of the polarizing plate with the retardation layer does not include the thickness of the second adhesive layer 50.

The polarizing plate with the retardation layer may further include other optical functional layers. The kind, characteristics, number, combination, arrangement position, and the like of the optical functional layers that can be provided on the polarizing plate with the retardation layer can be appropriately set according to the purpose. For example, the polarizing plate with a retardation layer may further have a conductive layer or an isotropic substrate with a conductive layer (neither shown). The conductive layer or the isotropic substrate with a conductive layer is typically disposed outside the second phase difference layer 22 (on the opposite side of the polarizer 10). In the case of an isotropic substrate provided with a conductive layer or with a conductive layer, the polarizing plate with a phase difference layer can be applied to a so-called internal touch panel type input display device in which a touch sensor is assembled between an image display panel and the polarizing plate. For example, the polarizing plate with a retardation layer may further include another retardation layer. The optical characteristics (for example, refractive index characteristics, in-plane retardation, nz coefficient, photoelastic modulus), thickness, arrangement position, and the like of the other retardation layer can be appropriately set according to the purpose.

The polarizing plate with the retardation layer may be monolithic or elongated. In the present specification, "elongated" means an elongated shape having a length relatively long with respect to the width, and includes, for example, an elongated shape having a length of 10 times or more, preferably 20 times or more with respect to the width. The long polarizing plate with the retardation layer can be wound in a roll.

Hereinafter, the constituent elements of the polarizing plate with a retardation layer will be described in more detail.

B. Polarizing plate

B-1 polarizer

As the polarizer 11, any suitable polarizer may be used. For example, the resin film forming the polarizer may be a single-layer resin film or a laminate of two or more layers.

Specific examples of the polarizer made of a single-layer resin film include hydrophilic polymer films such as polyvinyl alcohol (PVA, polyvinyl Alcohol) films, partially formalized PVA films, and ethylene-vinyl acetate copolymer partially saponified films, films obtained by dyeing and stretching a film using a dichroic substance such as iodine or a dichroic dye, and polyene oriented films such as a dehydrated product of PVA or a dehydrochlorination product of polyvinyl chloride. In view of excellent optical characteristics, a polarizer obtained by dyeing a PVA-based film with iodine and uniaxially stretching the film is preferably used.

The dyeing with iodine is performed, for example, by immersing the PVA-based film in an aqueous iodine solution. The stretching ratio of the uniaxial stretching is preferably 3 to 7 times. Stretching may be performed after dyeing treatment, or stretching may be performed while dyeing. Alternatively, the fabric may be dyed after stretching. The PVA-based film is subjected to swelling treatment, crosslinking treatment, washing treatment, drying treatment, and the like as needed. For example, by immersing the PVA-based film in water before dyeing and washing with water, not only dirt or an anti-blocking agent on the surface of the PVA-based film can be washed, but also the PVA-based film can be swelled to prevent uneven dyeing.

Specific examples of the polarizer obtained by using the laminate include a laminate of a resin substrate and a PVA-based resin layer (PVA-based resin film) laminated on the resin substrate, and a polarizer obtained by coating a laminate of a resin substrate and a PVA-based resin layer formed on the resin substrate. A polarizer obtained by using a laminate of a resin substrate and a PVA-based resin layer formed on the resin substrate can be produced, for example, by the following steps: coating a PVA-based resin solution on a resin substrate, drying the same, and forming a PVA-based resin layer on the resin substrate, thereby obtaining a laminate of the resin substrate and the PVA-based resin layer; the laminate was stretched and dyed to prepare a polarizer from the PVA-based resin layer. In the present embodiment, stretching typically includes immersing the laminate in an aqueous boric acid solution and stretching. Further, if necessary, stretching may further include air-stretching the laminate at a high temperature (for example, 95 ℃ or higher) before stretching in the aqueous boric acid solution. The obtained laminate of the resin substrate and the polarizer may be used as it is (that is, the resin substrate may be used as a protective layer for the polarizer), or the resin substrate may be peeled from the laminate of the resin substrate and the polarizer, and any appropriate protective layer according to the purpose may be laminated on the peeled surface. Details of the method for producing the polarizer are described in, for example, japanese patent application laid-open No. 2012-73580 and japanese patent No. 6470455. The entire disclosure of the above publication is incorporated by reference into the present specification.

The thickness of the polarizer is preferably 15 μm or less, more preferably 12 μm or less, further preferably 10 μm or less, particularly preferably 8 μm or less. On the other hand, the thickness of the polarizer is preferably 1 μm or more, more preferably 2 μm or more, and still more preferably 3 μm or more. When the thickness of the polarizer is in such a range, curling at the time of heating can be favorably suppressed, and excellent durability of appearance at the time of heating can be obtained.

The polarizer preferably exhibits absorption dichroism at any wavelength from 380nm to 780 nm. The polarizer has a monomer transmittance of, for example, 41.5% to 46.0%, preferably 43.0% to 46.0%, and more preferably 44.5% to 46.0%. The degree of polarization of the polarizer is preferably 97.0% or more, more preferably 99.0% or more, and still more preferably 99.9% or more.

B-2. Protective layer

The visible side protective layer 12 and the inner protective layer 13 each comprise any suitable film that can be used as a protective layer for a polarizer. Specific examples of the material of the main component of the film include cellulose resins such as triacetyl cellulose (TAC, triacetyl Cellulose), and transparent resins such as polyester resins, polyvinyl alcohol resins, polycarbonate resins, polyamide resins, polyimide resins, polyether sulfone resins, polysulfone resins, polystyrene resins, cyclic olefin resins (for example, polynorbornene resins), polyolefin resins, (meth) acrylic resins, and acetate resins. Further, a thermosetting resin such as a (meth) acrylic resin, a urethane resin, a (meth) acrylic urethane resin, an epoxy resin, or a silicone resin, an ultraviolet curable resin, or the like may be mentioned. In addition, for example, a vitreous polymer such as a siloxane polymer may be used. In addition, a polymer film described in Japanese patent application laid-open No. 2001-343529 (WO 01/37007) can also be used. As a material of the film, for example, a resin composition containing a thermoplastic resin having a substituted or unsubstituted imide group in a side chain and a thermoplastic resin having a substituted or unsubstituted phenyl group and a nitrile group in a side chain, for example, a resin composition having an alternating copolymer containing isobutylene and N-methylmaleimide and an acrylonitrile-styrene copolymer can be used. The polymer film may be, for example, an extrusion molded product of the above resin composition.

As described below, the polarizing plate with the retardation layer is typically disposed on the visible side of the image display device, and the visible side protective layer 12 is disposed on the visible side thereof. Accordingly, the visible side protective layer 12 may be subjected to surface treatments such as hard coat treatment, antireflection treatment, anti-blocking treatment, and antiglare treatment, as necessary. Further, if necessary, the visibility of the visible side protective layer 12 may be improved by a process (typically, a (elliptical) circularly polarized light function and an ultra-high phase difference) for improving visibility through polarized sunglasses. By performing such a treatment, excellent visibility can be achieved even when the display screen is visually recognized through a polarized lens such as polarized sunglasses. Therefore, the polarizing plate with the retardation layer can be suitably used for an image display device which can be used outdoors. The material constituting the visible side protective layer is preferably a cyclic olefin-based resin (for example, polynorbornene-based resin) or a cellulose-based resin (for example, TAC).

The thickness of the visible side protective layer 12 is preferably 5 μm to 80 μm, more preferably 10 μm to 40 μm, and still more preferably 10 μm to 30 μm. When the surface treatment is performed, the thickness of the visible side protective layer is a thickness including the thickness of the surface treatment layer.

The inner protective layer 13 is preferably optically isotropic in one embodiment. In the present specification, "optically isotropic" means that the in-plane retardation Re (550) is 0nm to 10nm and the retardation Rth (550) in the thickness direction is-10 nm to +10nm. The thickness of the inner protective layer 13 is preferably 5 μm to 80 μm, more preferably 10 μm to 40 μm, and still more preferably 10 μm to 30 μm. The material constituting the inner protective layer may preferably be a cyclic olefin-based (for example, polynorbornene-based), a cellulose-based resin (for example, TAC), or an acrylic resin.

C. Phase difference layer

C-1. First phase difference layer

The first retardation layer 21 typically functions as a λ/4 plate. The first retardation layer is typically provided for imparting an antireflection property to the image display device. The first retardation layer typically exhibits refractive index characteristics of nx > ny.gtoreq.nz as described above. The in-plane retardation Re (550) of the first retardation layer is preferably 100nm to 200nm, more preferably 110nm to 170nm, and still more preferably 120nm to 160nm as described above. Here, "ny=nz" includes not only the case where ny and nz are completely equal but also the case where ny and nz are substantially equal. Therefore, in the range where the effect of the present invention is not impaired, the case where ny > nz or ny < nz may exist.

The Nz coefficient of the retardation layer is preferably 0.9 to 1.5, more preferably 0.9 to 1.3. By satisfying such a relationship, an image display device having a very excellent reflection hue can be obtained.

The first phase difference layer preferably exhibits an inverse wavelength dispersion characteristic in which the phase difference value increases according to the wavelength of the measurement light. That is, the first retardation layer preferably satisfies the relationship of Re (450) < Re (550) as described above. The first retardation layer preferably satisfies Re (550 < Re (650)), re (450)/Re (550) of the first retardation layer is preferably 0.8 or more and less than 1, more preferably 0.8 to 0.95, re (650)/Re (550) of the first retardation layer is preferably 1.0 or more and less than 1.15, more preferably 1.03 to 1.1, and very excellent antireflective properties can be achieved with the above-described configuration.

The angle between the slow axis of the retardation layer and the absorption axis of the polarizer is preferably 40 ° to 50 °, more preferably 42 ° to 48 °, and still more preferably about 45 °. If the angle is in the above range, an image display device having very excellent antireflection characteristics can be obtained by using the phase difference layer as a λ/4 plate as described above.

The first retardation layer may be typically a liquid crystal alignment cured layer as described above. As described above, by using a liquid crystal compound, the difference between nx and ny of the obtained retardation layer can be significantly increased as compared with a non-liquid crystal material, and thus the thickness of the first retardation layer for obtaining a desired in-plane retardation can be significantly reduced. The first retardation layer is typically oriented (horizontally oriented) with the rod-like liquid crystal compound aligned in the slow axis direction of the retardation layer as described above.

Examples of the liquid crystal compound include a liquid crystal compound having a liquid crystal phase as a nematic phase (nematic liquid crystal). As the liquid crystal compound, for example, a liquid crystal polymer or a liquid crystal monomer can be used. The liquid crystal property of the liquid crystal compound may be expressed by a lyotropic type or a thermotropic type. The liquid crystal polymer and the liquid crystal monomer may be used alone or in combination.

When the liquid crystal compound is a liquid crystal monomer, the liquid crystal monomer is preferably a polymerizable monomer or a crosslinkable monomer. Since the alignment state of the liquid crystal monomer can be fixed by polymerizing or crosslinking (i.e., curing) the liquid crystal monomer. After the liquid crystal monomers are aligned, for example, if the liquid crystal monomers are polymerized or crosslinked with each other, the above-described alignment state can be fixed thereby. Here, although polymers are formed by polymerization and three-dimensional network structures are formed by crosslinking, they are non-liquid crystalline. Therefore, the first retardation layer formed does not undergo transition to a liquid crystal phase, a glass phase, or a crystal phase due to, for example, a temperature change peculiar to the liquid crystalline compound. As a result, the first retardation layer is extremely excellent in stability against temperature change.

The temperature range in which the liquid crystal monomer exhibits liquid crystallinity varies depending on the kind thereof. Specifically, the temperature is preferably in the range of 40 to 120 ℃, more preferably 50 to 100 ℃, and most preferably 60 to 90 ℃.

As the liquid crystal monomer, any suitable liquid crystal monomer may be used. For example, the polymerizable mesogenic compounds described in Japanese patent application laid-open No. 2002-533742 (WO 00/37585), EP358208 (US 5211877), EP66137 (US 4388453), WO93/22397, EP0261712, DE19504224, DE4408171, GB2280445 and the like can be used.

The thickness of the first retardation layer is typically set to a thickness that can function properly as a λ/4 plate. The thickness of the first retardation layer is preferably 0.5 μm to 7 μm, more preferably 1 μm to 5 μm. By using the liquid crystal compound, an in-plane retardation equivalent to that of the resin film can be achieved at a significantly thinner thickness than the resin film.

C-2 second phase difference layer

The second phase difference layer 22 may be a positive C plate whose refractive index characteristics show a relationship of nz > nx=ny, as described above. By using the positive C plate as the second phase difference layer, reflection in an oblique direction can be well prevented, and a wide viewing angle of an antireflection function becomes possible. In this case, the retardation Rth (550) in the thickness direction of the second phase difference layer is preferably-50 nm to-300 nm, more preferably-70 nm to-250 nm, still more preferably-90 nm to-200 nm, and particularly preferably-100 nm to-180 nm. Here, "nx=ny" includes not only the case where nx and ny are exactly equal but also the case where nx and ny are substantially equal. That is, the in-plane phase difference Re (550) of the second phase difference layer may be below 10nm.

The second phase difference layer may be formed of any suitable material. The second phase difference layer is preferably a film containing a liquid crystal material fixed to be vertically aligned. The vertically orientable liquid crystal material (liquid crystal compound) may be a liquid crystal monomer or a liquid crystal polymer. Specific examples of the method for forming the liquid crystal compound and the retardation layer include those described in [0020] to [0028] of JP-A-2002-333642 and methods for forming the retardation layer. In this case, the thickness of the second phase difference layer is preferably 0.5 μm to 10 μm, more preferably 0.5 μm to 8 μm, and still more preferably 0.5 μm to 5 μm.

D. Adhesive layer

The adhesive layer 30 contains an active energy ray-curable adhesive as described above. The cure shrinkage of the adhesive is typically 5% or more, preferably 7% or more, more preferably 10% or more, and even more preferably 14% or more, as described above. The upper limit of the cure shrinkage of the adhesive may be 20%, for example. With such a configuration, re (550) of the laminate of the first phase difference layer and the second phase difference layer (substantially the first phase difference layer) can be increased, and the front reflection hue a and b at the initial stage (before being placed in a high-temperature environment) of the image display device can be set to L ^* a ^* b ^* The chromaticity diagram in the color space is shifted in advance in the direction of change in the high-temperature environment. Therefore, the change Δa of the reflected hue under a high-temperature environment (for example, after a endurance test) can be reduced ^* b ^* . Further, when the laminate of the first retardation layer and the second retardation layer is annealed, the above-described effect may be obtained even when the curing shrinkage rate of the adhesive is smaller than the above-described range (for example, 3%).

As the active energy ray-curable adhesive, any suitable active energy ray-curable adhesive may be used as long as the curing shrinkage ratio can be in the above range. Examples of the active energy ray-curable adhesive include ultraviolet ray-curable adhesives and electron beam-curable adhesives. In addition, from the viewpoint of curing mechanism, examples of the active energy ray-curable adhesive include radical-curable adhesives, cationic-curable adhesives, anionic-curable adhesives, and mixtures of radical-curable adhesives and cationic-curable adhesives. Typically, a radical-curable ultraviolet-curable adhesive is used. Because of excellent versatility and easy adjustment of characteristics (constitution).

The active energy ray-curable adhesive typically contains a monofunctional component, a polyfunctional component (curing component), and a photopolymerization initiator. The monofunctional components and the polyfunctional components are each typically a radically polymerizable compound. Examples of the preferable monofunctional component include higher alkyl esters of (meth) acrylic acid and modified products thereof. Specific examples thereof include isostearyl acrylate, lauryl acrylate, acryloylmorpholine and epsilon-caprolactone modified with hydroxyalkyl unsaturated fatty acid. Examples of the preferable polyfunctional component include monomers and/or oligomers having 2 or more functional groups such as a (meth) acrylate group and a (meth) acrylamide group. Specific examples thereof include polyethylene glycol diacrylate, trimethylpropane triacrylate, and glycerol triacrylate. Specific examples of the monofunctional component or the polyfunctional component other than the above include tripropylene glycol diacrylate, 1, 9-nonanediol diacrylate, tricyclodecane dimethanol diacrylate, phenoxydiethylene glycol acrylate, cyclic trimethylolpropane formal acrylate, dioxane glycol diacrylate, EO-modified diglycerol tetraacrylate, gamma-butyrolactone acrylate, N-methylpyrrolidone, hydroxyethyl acrylamide, N-methylolacrylamide, N-methoxymethacrylamide, N-ethoxymethacrylamide and 9-vinylcarbazole. In one embodiment, the monofunctional or polyfunctional component has a cyclic structure. Specific examples thereof include acryloylmorpholine, gamma-butyrolactone acrylate, epsilon-caprolactone modified with an unsaturated fatty acid hydroxyalkyl ester, N-methylpyrrolidone, and 9-vinylcarbazole. The monofunctional component or the polyfunctional component may be used alone or in combination of 2 or more.

The active energy ray-curable adhesive may further contain a cationically polymerizable compound, if necessary. The cationically polymerizable compound may be monofunctional or polyfunctional. Examples of the monofunctional cationically polymerizable compound include p-tert-butylphenyl glycidyl ether and 3-ethyl-3- [ (2-ethylhexyl) oxy ] oxetane. Examples of the polyfunctional cationically polymerizable compound include 3-ethyl-3- { [ (3-ethyloxetan-3-yl) methoxy ] methyl } oxetan. As the cationically polymerizable compound, a silane coupling agent may be used. Examples of the silane coupling agent include 3-glycidoxypropyl trimethoxysilane.

The active energy ray-curable adhesive may further contain an acrylic oligomer, if necessary. The molecular weight of the acrylic oligomer can be appropriately set according to the purpose.

The active energy ray-curable adhesive may further contain a plasticizer (for example, an oligomer component), a crosslinking agent, a diluent, and the like, depending on the purpose. By adjusting the types, combinations, and blending ratios of these components, as well as the monofunctional component, the polyfunctional component, the cationically polymerizable compound, the acrylic oligomer, and the photopolymerization initiator, an active energy ray curable adhesive having a desired cure shrinkage ratio can be obtained. Further, the above-mentioned components may be commercially available ones.

The thickness of the cured active energy ray-curable adhesive is preferably 0.1 μm to 3.0 μm.

Details of the active energy ray-curable adhesive are described in, for example, japanese patent application laid-open No. 2018-017996. The description of this publication is incorporated by reference into this specification.

E. Adhesive layer

The first adhesive layer 40 and the second adhesive layer 50 may be formed of any suitable adhesive according to the purpose, and thus detailed description thereof will be omitted.

F. Method for manufacturing polarizing plate with phase difference layer

Embodiments of the present invention also include a method for manufacturing the polarizing plate with a retardation layer. The manufacturing method comprises the following steps: forming a first phase difference layer on a first substrate; forming a second phase difference layer on a second substrate; and bonding the first retardation layer of the laminate of the first base material and the first retardation layer to the second retardation layer of the laminate of the second base material and the second retardation layer via an active energy ray-curable adhesive, thereby forming an intermediate laminate. A typical example of this manufacturing method will be described below with reference to fig. 2.

First, as shown in fig. 2 (a), the first retardation layer 21 is formed on the first substrate 61. The first substrate may be any suitable resin film. Specific examples thereof include cellulose resin films such as triacetyl cellulose (TAC) films, polyester films such as polyethylene terephthalate (PET, polyethylene Terephthalate) films, and acrylic resin films. TAC films are preferred. The first phase difference layer may be typically formed by: an alignment treatment is performed on the surface of the first substrate, a coating liquid containing a liquid crystal compound is applied to the surface, the liquid crystal compound is aligned in a direction corresponding to the alignment treatment, and the alignment state is fixed. As the orientation treatment, any suitable orientation treatment may be employed. Specifically, a mechanical alignment treatment, a physical alignment treatment, and a chemical alignment treatment can be cited. Specific examples of the mechanical orientation treatment include a rubbing treatment and a stretching treatment. Specific examples of the physical alignment treatment include a magnetic field alignment treatment and an electric field alignment treatment. Specific examples of the chemical alignment treatment include oblique vapor deposition and photo-alignment treatment. The process conditions of the various orientation processes may employ any suitable conditions according to purposes. The alignment of the liquid crystal compound is performed by performing a treatment at a temperature at which a liquid crystal phase is exhibited, depending on the kind of the liquid crystal compound. By performing such a temperature treatment, the liquid crystal compound is brought into a liquid crystal state, and the liquid crystal compound is aligned in accordance with the alignment treatment direction of the substrate surface. In one embodiment, the fixing of the alignment state is performed by cooling the liquid crystal compound aligned as described above. In the case where the liquid crystal compound is a polymerizable monomer or a crosslinkable monomer, the alignment state is fixed by subjecting the liquid crystal compound thus aligned to a polymerization treatment or a crosslinking treatment. Thus, the first retardation layer 21 is formed on the first substrate 61.

On the other hand, as shown in fig. 2 (b), the second phase difference layer 22 is formed on the second base material 62. The second substrate may be any suitable resin film. Embodiments are as described above with respect to the first substrate. The second substrate is preferably a PET film. The second phase difference layer is formed, for example, as described above using the liquid crystal compounds described in [0020] to [0028] of Japanese unexamined patent publication No. 2002-333642. Thus, the second phase difference layer 22 is formed on the second base material 62.

Then, as shown in fig. 2 (c), the first retardation layer 21 and the second retardation layer 22 in each of the obtained laminated bodies are bonded via an active energy ray curable adhesive, thereby forming an intermediate laminated body. The active energy ray-curable adhesive is as described in item D above. More specifically, for example, an active energy ray-curable adhesive is applied to the surface of the second phase difference layer, and the first phase difference layer is brought into contact (typically, bonded) with the surface thereof to form a precursor of the intermediate laminate, and if necessary, the precursor is heated and irradiated with a specific cumulative amount of active energy rays (for example, ultraviolet rays) to cure the adhesive, thereby forming the intermediate laminate. Here, the cure shrinkage of the active energy ray-curable adhesive is typically 5% or more as described above. When the cure shrinkage is within such a range, the Re (550) of the first retardation layer can be increased by the shrinkage in forming the intermediate laminate, preferably by 0.5nm or more, more preferably by 1.0nm or more, still more preferably by 1.5nm or more, particularly preferably by 2.5nm or more, and particularly preferably by 3.0nm or more. As a result, the front reflection color phase a and b values at the initial stage (before being placed in a high-temperature environment) of the image display device can be set at L ^* a ^* b ^* The chromaticity diagram in the color space is shifted in advance in the direction of change in the high-temperature environment. Therefore, the change Δa of the reflected hue under a high-temperature environment (for example, after a endurance test) can be reduced ^* b ^* . However, in the case of performing the annealing treatment described below, even if the cure shrinkage is less than 5%, the effects of the embodiments of the present invention may be obtained.

Then, as shown in FIG. 2 (d), the intermediate laminate is subjected toAnd (5) annealing treatment. The treatment temperature of the annealing treatment is preferably 80℃or higher, more preferably 90℃or higher, still more preferably 95℃or higher, and particularly preferably 100℃or higher. The upper limit of the treatment temperature may be, for example, 120 ℃. The processing time may vary depending on the processing temperature. The treatment time is preferably 1 minute or more, more preferably 3 minutes or more, still more preferably 7 minutes or more, and particularly preferably 10 minutes or more. The upper limit of the treatment time may be, for example, 20 minutes. By performing the annealing treatment, re (550) of the first retardation layer can be increased by preferably 0.5nm or more, more preferably 1.0nm or more, still more preferably 1.5nm or more, particularly preferably 2.5nm or more, and particularly preferably 3.0nm or more. As a result, the front reflection color phase a and b values at the initial stage (before being placed in a high-temperature environment) of the image display device can be set at L ^* a ^* b ^* The chromaticity diagram in the color space is shifted in advance in the direction of change in the high-temperature environment. Therefore, the change Δa of the reflected hue under a high-temperature environment (for example, after a endurance test) can be reduced ^* b ^* . However, when the curing shrinkage of the active energy ray curable adhesive is 5% or more as described above, the effect of the embodiment of the present invention may be obtained even without performing the annealing treatment.

Preferably, it is: an intermediate laminate may be formed using an active energy ray-curable adhesive having a cure shrinkage of 5% or more, and the intermediate laminate may be subjected to an annealing treatment. As a result, re (550) of the first retardation layer can be further increased.

Then, as shown in fig. 2 (e), the first base material 61 is peeled off from the intermediate laminate, and the 1 st adhesive layer 40 is disposed on the peeled surface (the surface of the first retardation layer 21), and the polarizing plate is bonded via the 1 st adhesive layer 40. Since the polarizing plate can be manufactured by any appropriate method, a detailed description of a manufacturing method of the polarizing plate is omitted. In terms of practicality, as shown in fig. 2 (f), the second base material 62 is peeled off and removed, and the second adhesive layer 50 is disposed on the peeled surface (the surface of the second phase difference layer 22). For example, the second adhesive layer is formed on a release film (not shown), and the laminate of the second adhesive layer and the release film is disposed so that the second adhesive layer contacts the surface of the second phase difference layer. Thus, a polarizing plate with a retardation layer can be produced. The release film is removed when the polarizing plate with the retardation layer is used.

G. Image display device

The polarizing plate with a retardation layer according to any one of items A to F above can be applied to an image display device. Accordingly, an embodiment of the present invention includes an image device using such a polarizing plate with a retardation layer. An image display device according to an embodiment of the present invention is typically provided with the polarizing plate with a retardation layer described in the above items a to F on the visible side thereof. The polarizing plate with the retardation layer is laminated such that the retardation layer is on the image display panel side (such that the polarizing plate is on the viewing side). As the image display device, a liquid crystal display device, an organic Electroluminescence (EL) display device, and an inorganic EL display device are typically exemplified. In one embodiment, an image display device (for example, an organic EL display device) has a curved shape (substantially curved display screen), and/or can be curved or bent.

Examples

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 indicated, "parts" and "%" in examples and comparative examples are based on weight.

(1) Shrinkage on curing

The ultraviolet curable adhesives used in examples and comparative examples were used to measure cure shrinkage using a resin cure shrinkage stress measuring device "EU201" manufactured by settech corporation.

(2) Value of phase difference rise

The first retardation layer (before the intermediate layer stack was produced) and the intermediate layer stack (after the annealing treatment in the case of annealing treatment) produced in the examples and comparative examples were subjected to in-plane retardation measurement using a retardation measurement device (product name "axi Scan") manufactured by Axometrics corporation. The in-plane phase difference was measured at a wavelength of 550nm and at a temperature of 23 ℃. The difference between the in-plane retardation of the intermediate laminate and the in-plane retardation of the first retardation layer before the production of the intermediate laminate is set to a "retardation rise value". The in-plane retardation of the intermediate laminate is substantially the in-plane retardation of the first retardation layer in the laminate.

(3)Δa ^* b ^*

The polarizing plates with retardation layers obtained in examples and comparative examples were bonded to an alkali-free glass plate to prepare test samples. The test sample was subjected to a durability test at 80℃for 500 hours. Test samples before and after the endurance test were placed on a mirror plate, and the a value and the b value were measured using a spectrocolorimeter and a colorimeter "CM-26d" manufactured by Konica Minolta, inc., and the difference was set as Δa ^* b ^* 。

Production examples 1 to 4: preparation of ultraviolet-curable adhesives A to D

The components shown in Table 1 were mixed in the ratios shown in Table 1 to prepare ultraviolet curable adhesives A to D. The cure shrinkage of the uv curable adhesives a to D are shown in table 1. The meanings of the terms shown in table 1 are as follows.

ACMO: acryloylmorpholine manufactured by KJ Chemicals Co

PLACCEL FA1DDM: unsaturated fatty acid hydroxyalkyl ester modified epsilon-caprolactone manufactured by Daicel company

ISTA: isostearyl acrylate manufactured by Osaka organic chemical industry Co

Light Acrylate L-A: lauryl acrylate manufactured by co-Rong chemical Co

Ext> Lightext> Acrylateext> 14ext> EGext> -ext> Aext>:ext> Polyethylene glycol diacrylate manufactured by Cogrong chemical Co Ltd

Light Acrylate TMP-A: trimethylpropane triacrylate manufactured by co-Rong chemical Co., ltd

Aromix M-930: glycerol triacrylate manufactured by east Asia Synthesis Co

KBM-403: 3-glycidoxypropyl trimethoxysilane from the company Xinyue chemical industry

EX-146: p-tert-butylphenyl glycidyl ether manufactured by Nagase ChemteX Co

OXT-212: 3-Ethyl-3- [ (2-ethylhexyl) oxy ] oxetane manufactured by east Asia Synthesis Co., ltd

OXT-221: 3-ethyl-3- { [ (3-ethyloxetan-3-yl) methoxy ] methyl } oxetan manufactured by east Asia Synthesis Co., ltd

ARUFON UP-1190: manufactured by east Asia Synthesis Co Ltd

ARUFON UG-4010: manufactured by east Asia Synthesis Co Ltd

Omnirad 819: manufactured by IGMresin Co

CPI-110P: san-Apro Co

TABLE 1

Example 1

1. Manufacture of polarizer

As the thermoplastic resin substrate, an amorphous isophthalic acid-copolymerized polyethylene terephthalate film (thickness: 100 μm) having a long shape, a water absorption of 0.75% and a Tg of about 75℃was used. Corona treatment is performed on one side of the resin base material.

Polyvinyl alcohol (polymerization degree 4200, saponification degree 99.2 mol%) and acetoacetyl-modified PVA (trade name "GOHSEFIMER Z410" manufactured by Nippon chemical industry Co., ltd.) were blended in an amount of 9:1 to 100 parts by weight of the mixed PVA-based resin, 13 parts by weight of potassium iodide was added and dissolved in water, to prepare an aqueous PVA solution (coating liquid).

The PVA aqueous solution was applied to the corona treated surface of the resin substrate and dried at 60 ℃ to form a PVA-based resin layer having a thickness of 13 μm, thereby producing a laminate.

The obtained laminate was subjected to free-end uniaxial stretching to 2.4 times in the machine direction (longitudinal direction) between rolls having different peripheral speeds in an oven at 130 ℃.

Subsequently, the laminate was immersed in an insolubilization bath (an aqueous boric acid solution obtained by mixing 4 parts by weight of boric acid with 100 parts by weight of water) at a liquid temperature of 40 ℃ for 30 seconds (insolubilization treatment).

Then, the resultant polarizing film was immersed in a dyeing bath (an aqueous iodine solution obtained by mixing iodine and potassium iodide in a weight ratio of 1:7 with respect to 100 parts by weight of water) at a liquid temperature of 30℃for 60 seconds while adjusting the concentration so that the monomer transmittance (Ts) of the finally obtained polarizing film became a desired value (dyeing treatment).

Then, the resultant mixture was immersed in a crosslinking bath (aqueous boric acid solution obtained by mixing 3 parts by weight of potassium iodide with 5 parts by weight of boric acid per 100 parts by weight of water) at a liquid temperature of 40℃for 30 seconds (crosslinking treatment).

Thereafter, the laminate was uniaxially stretched in the machine direction (longitudinal direction) between rolls having different peripheral speeds while being immersed in an aqueous boric acid solution (boric acid concentration 4.0 wt% and potassium iodide 5.0 wt%) having a liquid temperature of 70 ℃ so that the total stretching ratio became 5.5 times (in-water stretching treatment).

Thereafter, the laminate was immersed in a washing bath (aqueous solution obtained by mixing 4 parts by weight of potassium iodide with 100 parts by weight of water) having a liquid temperature of 20 ℃ (washing treatment).

Thereafter, the resultant was dried in an oven maintained at 90℃and then contacted with a heated roll of SUS having a surface temperature of 75℃for about 2 seconds (drying shrinkage treatment). The shrinkage in the width direction of the laminate subjected to the drying shrinkage treatment was 5.2%.

Thus, a polarizer having a thickness of 5 μm was formed on the resin substrate.

2. Manufacture of polarizer

An HC-COP film was bonded to the polarizer surface of the laminate of the resin substrate and polarizer obtained as described above via an ultraviolet curable adhesive. Specifically, the cured adhesive was applied so that the thickness of the cured adhesive became 1.0 μm, and the cured adhesive was bonded by using a roll press. Thereafter, UV (Ultraviolet) light is irradiated from the HC-TAC film side and the adhesive is cured. The HC-COP film is a film in which a Hard Coat (HC) layer (thickness of 2 μm) is formed on a cycloolefin resin (COP) film (thickness of 25 μm), and is bonded so that the COP film is on the polarizer side. Then, the resin substrate was peeled off, and a TAC film having Re (550) of about 0nm to 2nm was bonded to the peeled off surface in the same manner as described above. Thus, a polarizing plate was obtained.

3. Fabrication of liquid crystal alignment cured layer constituting retardation layer

3-1. First phase difference layer

To 400 parts of Cyclopentanone (CPN), 55 parts of the compound represented by formula (I), 25 parts of the compound represented by formula (II), and 20 parts of the compound represented by formula (III) were added, and after heating and stirring at 60 ℃ to dissolve the compounds, the solution was returned to room temperature after confirming the dissolution, 3 parts of Irgacure 907 (manufactured by BASF Japan corporation), 0.2 part of MEGAFAC F-554 (manufactured by DIC corporation), and 0.1 part of p-Methoxyphenol (MEHQ) were added, and further stirred to obtain a solution. The solution was transparent and homogeneous. The obtained solution was filtered through a 0.20 μm membrane filter to obtain a polymerizable composition. On the other hand, a polyimide solution for an alignment film was coated on a TAC substrate using a spin coating method, dried at 100 ℃ for 10 minutes, and then baked at 200 ℃ for 60 minutes, thereby obtaining a coating film. The obtained coating film was subjected to a rubbing treatment to form an alignment film. The rubbing treatment was performed using a commercially available rubbing device. The polymerizable composition obtained above was applied to the surface of the alignment film by spin coating, and dried at 100℃for 2 minutes. After cooling the obtained coating film to room temperature, it was cooled to 30mW/cm by using a high-pressure mercury lamp ² The intensity of (a) was irradiated with an external light for 30 seconds Zhong Zi to obtain a liquid crystal alignment cured layer (thickness: 4 μm). The in-plane phase difference Re (550) of the liquid crystal alignment cured layer was 130nm. In addition, the liquid crystal alignment cured layer had Re (450)/Re (550) of 0.851, showing the reverse wavelength dispersion characteristics.

[ chemical formula 1 ]]

[ chemical 2]

3-2 second phase difference layer

A liquid crystal coating liquid was prepared by dissolving 20 parts by weight of a side chain type liquid crystal polymer represented by the following chemical formula (1) (wherein numerals 65 and 35 in the formula represent mol% of monomer units, and are simply represented by block polymers: weight average molecular weight 5000), 80 parts by weight of a polymerizable liquid crystal (manufactured by BASF: paliocolarLC 242) exhibiting a nematic liquid crystal phase, and 5 parts by weight of a photopolymerization initiator (manufactured by Ciba Specialty Chemicals: irgacure 907) in 200 parts by weight of cyclopentanone. Then, the coating liquid was applied to the PET substrate subjected to the vertical alignment treatment by a bar coater, and then heated and dried at 80 ℃ for 4 minutes, thereby aligning the liquid crystal. The liquid crystal layer was cured by irradiating ultraviolet rays thereto, and a second phase difference layer (thickness 3 μm) exhibiting refractive index characteristics of nz > nx=ny was formed on the substrate.

[ chemical 3]

4. Production of polarizing plate with retardation layer

The first retardation layer and the second retardation layer in each of the laminated bodies obtained in the above 3-1 and 3-2 were bonded via a UV adhesive a (thickness after curing 1 μm), thereby forming an intermediate laminated body. The intermediate laminate was subjected to an annealing treatment at 100℃for 10 minutes. The TAC base material was peeled off from the intermediate laminate after the annealing treatment, and an acrylic adhesive (thickness 5 μm) was disposed on the surface of the first retardation layer, and a polarizing plate was bonded via the acrylic adhesive. At this time, the polarizing plate was bonded so that the TAC film was on the first retardation layer side. Next, the PET substrate was peeled off, and a laminate of an acrylic adhesive (26 μm in thickness)/a release film was disposed on the surface of the second phase difference layer. Thus, a polarizing plate with a retardation layer was produced. The obtained polarizing plate with a retardation layer was subjected to the evaluation of (3) above. The results are shown in Table 2.

Examples 2 to 13 and comparative examples 1 to 3

A polarizing plate with a retardation layer was obtained in the same manner as in example 1, except that the UV adhesive shown in table 2 was used and the intermediate laminate was annealed under the conditions shown in table 2. The obtained polarizing plate with a retardation layer was subjected to the same evaluation as in example 1. The results are shown in Table 2. In table 2, "none" in the column of annealing treatment indicates that annealing treatment was not performed.

TABLE 2

[ evaluation ]

As is clear from Table 2, the polarizing plate with a retardation layer according to the example of the present invention has a smaller Δa than that of the comparative example ^* b ^* Smaller. That is, it is understood that the polarizing plate with a retardation layer according to the embodiment of the present invention can realize an image display device in which the change in reflection hue under a high-temperature environment is suppressed.

[ Industrial applicability ]

The polarizing plate with a retardation layer of the present invention is suitably used as a circular polarizing plate for antireflection of an image display device.

Symbol description

10: polarizing plate

11: polarizer

12: protective layer

13: protective layer

21: first phase difference layer

22: second phase difference layer

30: adhesive layer

40: first adhesive layer

50: second adhesive layer

100: polarizing plate with phase difference layer

Claims

1. A polarizing plate with a retardation layer, comprising: a polarizing plate including a polarizer and a protective layer disposed on at least one side of the polarizer; a first retardation layer disposed on the opposite side of the polarizing plate from the viewing side; and a second phase difference layer bonded to the opposite side of the first phase difference layer from the polarizing plate via an adhesive layer,

the first phase difference layer is a phase difference layer other than a C plate, the second phase difference layer is a C plate,

The adhesive layer contains an active energy ray-curable adhesive, and the adhesive has a cure shrinkage rate of 5% or more.

2. A polarizing plate with a retardation layer, comprising: a polarizing plate including a polarizer and a protective layer disposed on at least one side of the polarizer; a first retardation layer disposed on the opposite side of the polarizing plate from the viewing side; and a second phase difference layer bonded to the opposite side of the first phase difference layer from the polarizing plate via an adhesive layer,

the laminate of the first phase difference layer and the second phase difference layer is annealed.

3. The polarizing plate with a retardation layer as claimed in claim 1 or 2, wherein the first retardation layer exhibits refractive index characteristics of nx > ny.gtoreq.nz, re (550) is 100nm to 200nm and satisfies the relationship of Re (450) < Re (550),

the second phase difference layer exhibits refractive index characteristics of nz > nx=ny,

re (450) and Re (550) are in-plane retardation measured at 23℃by light having wavelengths of 450nm and 550nm, respectively.

4. The polarizing plate with a retardation layer as claimed in claim 3, wherein the first retardation layer and the second retardation layer are alignment cured layers of liquid crystal compounds.

5. The method for producing a polarizing plate with a retardation layer according to claim 1, comprising:

forming the first phase difference layer on a first substrate;

forming the second phase difference layer on a second substrate; and

bonding the first retardation layer of the laminate of the first base material and the first retardation layer to the second retardation layer of the laminate of the second base material and the second retardation layer via an active energy ray curable adhesive to form an intermediate laminate,

the curing shrinkage rate of the active energy ray curing adhesive is more than 5%.

6. The manufacturing method according to claim 5, comprising: when the intermediate laminate is formed, re (550) of the first retardation layer is increased by 0.5nm or more.

7. The method for producing a polarizing plate with a retardation layer according to claim 2, comprising:

forming the first phase difference layer on a first substrate;

forming the second phase difference layer on a second substrate;

bonding the first retardation layer of the laminate of the first base material and the first retardation layer to the second retardation layer of the laminate of the second base material and the second retardation layer via an active energy ray-curable adhesive, thereby forming an intermediate laminate; and

The intermediate laminate is annealed.

8. The method according to claim 7, wherein the annealing treatment is performed at a treatment temperature of 80 ℃ or higher and a treatment time of 1 minute or higher.

9. The manufacturing method according to claim 7 or 8, comprising: re (550) of the first retardation layer is increased by 0.5nm or more by the annealing treatment.

10. An image display device comprising the polarizing plate with a retardation layer according to any one of claims 1 to 4.