JP2022106205A - Laminate and method for manufacturing polarizing plate with retardation layer - Google Patents

Abstract

To provide a polarizing plate with a retardation layer whose warpage is prevented.SOLUTION: A laminate according to an embodiment of the present invention is a laminate having a first protective film, a polarizing plate including a polarizer and a protective layer arranged on at least one side of the polarizer, a retardation layer, and a second protective film in this order. The total of the thickness of the polarizing plate and the thickness of the retardation layer is 70 μm or less. The center in the thickness direction of the polarizer is located within a range of 10% or less of half the thickness of the laminate from the center in the thickness direction of the laminate.SELECTED DRAWING: Figure 4

Description

The present invention relates to a method for manufacturing a laminated body and a polarizing plate with a retardation layer.

Image display devices represented by liquid crystal displays and electroluminescence (EL) display devices (for example, organic EL display devices and inorganic EL display devices) are rapidly becoming widespread. A polarizing plate and a retardation plate are typically used in an image display device. Practically, a polarizing plate with a retardation layer in which a polarizing plate and a retardation plate are integrated is widely used (for example, Patent Document 1). In recent years, the possibility of bending, bending, folding, and winding of an image display device using a flexible substrate (for example, a resin substrate) has been studied. As a polarizing plate with a retardation layer used in such an image display device, a thin polarizing plate with a retardation layer is desired. However, the thin polarizing plate with a retardation layer has a problem that warpage is likely to occur.

Japanese Patent No. 3325560

The present invention has been made to solve the above-mentioned conventional problems, and a main object thereof is to provide a polarizing plate with a retardation layer in which warpage is suppressed.

According to an embodiment of the present invention, a laminate is provided. This laminate has a first protective film, a polarizing plate including a polarizing element and a protective layer arranged on at least one side of the polarizing element, a retardation layer, and a second protective film in this order. The total thickness of the polarizing plate and the thickness of the retardation layer is 70 μm or less, and the center of the polarizing element in the thickness direction is half of the thickness direction of the laminate. It is located within the range of 10% or less of the thickness.
In one embodiment, the ratio of the thickness of the polarizing plate to the thickness of the retardation layer is 5 or more.
In one embodiment, the polarizing plate has a protective layer arranged only on the side of the polarizing element on which the retardation layer is not arranged.
In one embodiment, the retardation layer is an oriented solidified layer of a liquid crystal compound.
In one embodiment, the thickness of the first protective film is 15 μm or more and 90 μm or less.
In one embodiment, the thickness of the second protective film is 40 μm or more.
According to another embodiment of the present invention, there is provided a method for manufacturing a polarizing plate with a retardation layer. This manufacturing method includes preparing the laminate and storing the laminate.
In one embodiment, the manufacturing method comprises laminating the polarizing plate and the retardation layer to obtain a laminate precursor.
In one embodiment, the production method comprises cutting the laminate precursor into a single-wafer shape.
In one embodiment, the manufacturing method comprises laminating the polarizing plate and the retardation layer using an active energy ray-curable adhesive.
In one embodiment, the thickness of the active energy ray-curable adhesive after curing is 0.4 μm or more.
In one embodiment, the manufacturing method comprises humidifying the laminate prior to storage.

According to the embodiment of the present invention, in a laminated body having a polarizing plate and a retardation layer, the center of the polarizing element is positioned within a predetermined range to obtain a polarizing plate with a retardation layer in which warpage is suppressed. Can be done.

It is a schematic sectional drawing which shows the schematic structure of the laminated body which concerns on 1st Embodiment of this invention. It is a schematic sectional drawing which shows the schematic structure of the laminated body which concerns on 2nd Embodiment of this invention. It is sectional drawing which shows an example of the warped state of a laminated body precursor. It is a figure for demonstrating the positional relationship between the center of a polarizing element, and the center of a laminated body.

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

(Definition of terms and symbols)
Definitions of terms and symbols herein are as follows.
(1) Refractive index (nx, ny, nz)
"Nx" is the refractive index in the direction in which the refractive index in the plane is maximized (that is, the direction of the slow phase axis), and "ny" is the direction orthogonal to the slow phase axis in the plane (that is, the direction of the phase advance axis). Is the refractive index of, and "nz" is the refractive index in the thickness direction.
(2) In-plane phase difference (Re)
“Re (λ)” is an in-plane phase difference measured with light having a wavelength of λ nm at 23 ° C. For example, "Re (550)" is an in-plane phase difference measured with light having a wavelength of 550 nm at 23 ° C. Re (λ) is obtained by the formula: Re (λ) = (nx−ny) × d, where d (nm) is the thickness of the layer (film).
(3) Phase difference in the thickness direction (Rth)
“Rth (λ)” is a phase difference in the thickness direction measured with light having a wavelength of λ nm at 23 ° C. For example, "Rth (550)" is a phase difference in the thickness direction measured with light having a wavelength of 550 nm at 23 ° C. Rth (λ) is obtained by the formula: Rth (λ) = (nx-nz) × d, where d (nm) is the thickness of the layer (film).
(4) Nz coefficient The Nz coefficient is obtained by Nz = Rth / Re.
(5) Angle When referring to an angle herein, the angle includes both clockwise and counterclockwise with respect to the reference direction. Therefore, for example, "45 °" means ± 45 °.

A method for manufacturing a polarizing plate with a retardation layer according to one embodiment of the present invention is to prepare a laminate having a polarizing plate containing a polarizing element and a retardation layer, and to put the laminate under a predetermined environment. Includes placing and humidifying.

A. Laminated Body FIG. 1 is a schematic cross-sectional view showing a schematic configuration of a laminated body according to the first embodiment of the present invention. The laminate 100 has a first protective film 31, a polarizing plate 10, a retardation layer 20, and a second protective film 32 in this order from the visual recognition side. In the illustrated example, the polarizing plate 10 includes a polarizing element 11 and a protective layer 12 arranged on the visible side of the polarizing element 11 (the side on which the retardation layer 20 is not arranged), and has a phase difference from the polarizing element 11. No protective layer is arranged between the layer 20 and the layer 20. According to such a form, for example, the thickness, total thickness, and thickness ratio of the polarizing plate described later can be satisfactorily achieved.

Although not shown, a protective layer may be further included on the other side of the polarizing element 11 (between the polarizing element 11 and the retardation layer 20).

FIG. 2 is a schematic cross-sectional view showing a schematic configuration of a laminated body according to a second embodiment of the present invention. In the first embodiment, the retardation layer 20 is a single layer, whereas in the second embodiment, the retardation layer 20 has a laminated structure including the first retardation layer 21 and the second retardation layer 22. have. Unlike the illustrated example, the retardation layer 20 may have a laminated structure of three or more layers.

Although not shown, the laminate may further have other functional layers. The types, characteristics, numbers, combinations, arrangements, and the like of the functional layers that the laminated body can have can be appropriately set according to the purpose. For example, the laminate may further have a conductive layer or an isotropic substrate with a conductive layer. The conductive layer or the isotropic base material with the conductive layer is typically arranged between the retardation layer 20 and the second protective film 32. A laminate having a conductive layer or an isotropic substrate with a conductive layer (polarizing plate with a retardation layer) is applied to, for example, an image display device in which a touch sensor is incorporated inside an image display panel. As another example, the laminate may further have other retardation layers. The optical characteristics (for example, refractive index characteristics, in-plane retardation, Nz coefficient, photoelastic coefficient), thickness, arrangement, and the like of the other retardation layers can be appropriately set according to the purpose. As a specific example, on the visual recognition side of the polarizing element 11, another retardation layer (typically, a layer that imparts a (elliptical) circular polarization function) that improves visibility when visually recognizing through polarized sunglasses, a super A layer that imparts a high phase difference) may be provided. By having such a layer, excellent visibility can be realized even when the display screen is visually recognized through a polarizing lens such as polarized sunglasses. Therefore, the obtained polarizing plate with a retardation layer can be suitably applied to an image display device that can be used outdoors.

Each member constituting the laminate may be laminated via any suitable adhesive layer (not shown). Specific examples of the adhesive layer include an adhesive layer and an adhesive layer. For example, the first protective film 31 is attached to the polarizing plate 10 via the pressure-sensitive adhesive layer. The first protective film 31 is used until the polarizing plate with a retardation layer obtained by the embodiment of the present invention is used (until it is laminated on an image display panel), or the final product (image display device). It may be peeled off in the manufacturing process, or it may be mounted as it is in the final product.

For example, the second protective film 32 is attached to the retardation layer 20 via the pressure-sensitive adhesive layer. Practically, the second protective film 32 can function as a release film (separator) to be temporarily attached until the polarizing plate with a retardation layer obtained by the embodiment of the present invention is put into use. By temporarily attaching the release film, for example, it is possible to protect the pressure-sensitive adhesive layer and form a roll of the laminated body.

For example, the retardation layer 20 is attached to the polarizing plate 10 via an adhesive layer (preferably using an active energy ray-curable adhesive). When the retardation layer 20 has a laminated structure of two or more layers, the respective retardation layers are bonded via an adhesive layer (preferably using an active energy ray-curable adhesive).

A-1. Polarizing plate The above polarizing plate includes a polarizing element and a protective layer. The thickness of the polarizing plate is preferably 20 μm or more, more preferably 25 μm or more, although it depends on the number of protective layers contained. On the other hand, the thickness of the polarizing plate is preferably 40 μm or less, more preferably 36 μm or less, and further preferably 33 μm or less. The thickness of the polarizing plate does not include the thickness of the adhesive layer (for example, the adhesive layer) when laminating the polarizing element and the protective layer.

The above-mentioned polarizing element is typically a resin film containing a dichroic substance (for example, iodine). Examples of the resin film include a hydrophilic polymer film such as a polyvinyl alcohol (PVA) -based film, a partially formalized PVA-based film, and an ethylene / vinyl acetate copolymer-based partially saponified film.

The thickness of the splitter is preferably 15 μm or less, more preferably 12 μm or less, and further preferably 10 μm or less. On the other hand, the thickness of the polarizing element is preferably 1 μm or more.

The splitter preferably exhibits absorption dichroism at any wavelength of 380 nm to 780 nm. The simple substance transmittance of the substituent is, for example, 41.5% to 46.0%, preferably 42.0% to 46.0%, and more preferably 44.5% to 46.0%. The degree of polarization of the polarizing element is preferably 97.0% or more, more preferably 99.0% or more, and further preferably 99.9% or more.

The protective layer may be formed of any suitable film that can be used as a protective layer for the stator. Specific examples of the material that is the main component of the film include cellulosic resins such as triacetylcellulose (TAC), polyesters, polyvinyl alcohols, polycarbonates, polyamides, polyimides, polyethersulfones, and polysulfones. Examples thereof include polystyrene-based, cycloolefin-based resins such as polysulfone, polyolefin-based, (meth) acrylic-based, and acetate-based resins.

The polarizing plate with a retardation layer obtained by the embodiment of the present invention is typically arranged on the visual recognition side of an image display device, and the protective layer 12 is arranged on the visual recognition side. Therefore, the protective layer 12 may be subjected to surface treatment such as hard coat (HC) treatment, antireflection treatment, anti-sticking treatment, and anti-glare treatment, if necessary.

The thickness of the protective layer 12 is preferably 5 μm to 80 μm, more preferably 10 μm to 40 μm, and even more preferably 10 μm to 30 μm. When the surface treatment is applied, the thickness of the protective layer 12 is the thickness including the thickness of the surface treatment layer.

The protective layer (not shown) disposed between the splitter 11 and the retardation layer 20 is preferably optically isotropic in one embodiment. As used herein, "optically isotropic" means that the in-plane retardation Re (550) is 0 nm to 10 nm and the thickness direction retardation Rth (550) is -10 nm to +10 nm. Say. The thickness of the protective layer arranged between the polarizing element 11 and the retardation layer 20 is preferably 5 μm to 80 μm, more preferably 10 μm to 40 μm, and further preferably 10 μm to 30 μm.

The polarizing plate can be made by any suitable method. Specifically, the polarizing plate may contain a polarizing element made from a single-layer resin film, or may contain a polarizing element obtained by using a laminated body having two or more layers.

The method for producing a polarizing element from the single-layer resin film typically includes subjecting the resin film to a dyeing treatment and a stretching treatment with a dichroic substance such as iodine or a dichroic dye. As the resin film, as described above, for example, a hydrophilic polymer film such as a polyvinyl alcohol (PVA) -based film, a partially formalized PVA-based film, and an ethylene / vinyl acetate copolymer-based partially saponified film is used. The method may further include insolubilization treatment, swelling treatment, cross-linking treatment and the like. A polarizing plate can be obtained by laminating a protective layer on at least one of the obtained polarizing elements. Since such a manufacturing method is well-known and customary in the art, detailed description thereof will be omitted.

Specific examples of the polarizing element obtained by using the above-mentioned laminate include a laminate of a resin base material and a PVA-based resin layer (PVA-based resin film) laminated on the resin base material, or a resin base material and the said material. Examples thereof include a polarizing element obtained by using a laminate with a PVA-based resin layer coated and formed on a resin base material. The ligand obtained by using the laminate of the resin base material and the PVA-based resin layer coated and formed on the resin base material is, for example, a resin base material obtained by applying a PVA-based resin solution to the resin base material and drying the resin base material. It is produced by forming a PVA-based resin layer on top of the PVA-based resin layer to obtain a laminate of a resin base material and a PVA-based resin layer; obtain. In the present embodiment, a polyvinyl alcohol-based resin layer containing a halide and a polyvinyl alcohol-based resin is preferably formed on one side of the resin base material. Stretching typically involves immersing the laminate in an aqueous boric acid solution for stretching. Further, stretching may further comprise, if necessary, stretching the laminate in the air at a high temperature (eg, 95 ° C. or higher) prior to stretching in boric acid aqueous solution. In addition, in the present embodiment, preferably, the laminate is subjected to a drying shrinkage treatment in which the laminate is shrunk by 2% or more in the width direction by heating while being conveyed in the longitudinal direction. Typically, the production method of the present embodiment includes subjecting the laminate to an aerial auxiliary stretching treatment, a dyeing treatment, an underwater stretching treatment, and a drying shrinkage treatment in this order. By introducing the auxiliary stretching, even when PVA is applied on the thermoplastic resin, the crystallinity of PVA can be enhanced and high optical characteristics can be achieved. At the same time, by increasing the orientation of PVA in advance, it is possible to prevent problems such as deterioration of PVA orientation and dissolution when immersed in water in a subsequent dyeing step or stretching step, and high optical characteristics. Will be possible to achieve. Further, when the PVA-based resin layer is immersed in a liquid, the disorder of the orientation of the polyvinyl alcohol molecule and the decrease in the orientation can be suppressed as compared with the case where the PVA-based resin layer does not contain a halide. This makes it possible to improve the optical characteristics of the polarizing element obtained through a treatment step of immersing the laminate in a liquid, such as a dyeing treatment and a stretching treatment in water. Further, the optical characteristics can be improved by shrinking the laminated body in the width direction by the drying shrinkage treatment. The obtained resin base material / polarizing element laminate may be used as it is (that is, the resin base material may be used as a protective layer for the polarizing element), and the resin base material is peeled off from the resin base material / polarizing element laminate. Any suitable protective layer according to the purpose may be laminated and used on the peeled surface or the surface opposite to the peeled surface. Details of the method for producing such a polarizing element are described in, for example, Japanese Patent Application Laid-Open No. 2012-73580 and Japanese Patent No. 6470455. The entire description of these publications is incorporated herein by reference.

A-2. Phase difference layer The thickness of the retardation layer is preferably 8 μm or less, and more preferably 5 μm or less, although it depends on the structure (whether it is a single layer or has a laminated structure). On the other hand, the thickness of the retardation layer is, for example, 1 μm or more. When the retardation layer has a laminated structure, the "thickness of the retardation layer" means the total thickness of each retardation layer. Specifically, the "thickness of the retardation layer" does not include the thickness of the adhesive layer (for example, the adhesive layer).

As the retardation layer, an oriented solidified layer of a liquid crystal compound (liquid crystal oriented solidified layer) is preferably used. By using a liquid crystal compound, the difference between nx and ny of the obtained retardation layer can be significantly increased as compared with the non-liquid crystal material, so that the thickness of the retardation layer for obtaining a desired in-plane retardation can be obtained. Can be made much smaller. Therefore, it is possible to realize a remarkable reduction in thickness of the polarizing plate with a retardation layer. As used herein, the term "aligned solidified layer" refers to a layer in which a liquid crystal compound is oriented in a predetermined direction within the layer and the oriented state is fixed. The "oriented solidified layer" is a concept including an oriented cured layer obtained by curing a liquid crystal monomer as described later. In the retardation layer, the rod-shaped liquid crystal compounds are typically oriented in a state of being aligned in the slow axis direction of the retardation layer (homogeneous orientation).

In the liquid crystal alignment solidification layer, the surface of a predetermined base material is subjected to an orientation treatment, and a coating liquid containing a liquid crystal compound is applied to the surface to orient the liquid crystal compound in a direction corresponding to the alignment treatment. It can be formed by fixing the orientation state. As the orientation treatment, any appropriate orientation treatment can be adopted. Specific examples thereof include mechanical orientation treatment, physical orientation treatment, and chemical orientation treatment. Specific examples of the mechanical orientation treatment include a rubbing treatment and a stretching treatment. Specific examples of the physical orientation treatment include magnetic field orientation treatment and electric field orientation treatment. Specific examples of the chemical alignment treatment include an orthorhombic vapor deposition method and a photoalignment treatment. As the treatment conditions for various orientation treatments, any appropriate conditions may be adopted depending on the purpose.

The orientation of the liquid crystal compound is performed by treating at a temperature indicating the liquid crystal phase according to the type of the liquid crystal compound. By performing such temperature treatment, the liquid crystal compound takes a liquid crystal state, and the liquid crystal compound is oriented according to the orientation treatment direction of the surface of the substrate.

In one embodiment, the orientation state is fixed by cooling the liquid crystal compound oriented as described above. When the liquid crystal compound is a polymerizable monomer or a crosslinkable monomer, the orientation state is fixed by subjecting the liquid crystal compound oriented as described above to a polymerization treatment or a crosslinking treatment.

Specific examples of the liquid crystal compound and details of the method for forming the oriented solidified layer are described in JP-A-2006-163343. The description of this publication is incorporated herein by reference.

As described above, the retardation layer 20 may be a single layer or may have a laminated structure of two or more layers.

As shown in FIG. 1, in one embodiment where the retardation layer 20 is a single layer, the retardation layer 20 can function as a λ / 4 plate. Specifically, the Re (550) of the retardation layer is preferably 100 nm to 180 nm, more preferably 110 nm to 170 nm, and further preferably 110 nm to 160 nm. The thickness of the retardation layer can be adjusted to obtain the desired in-plane retardation of the λ / 4 plate. When the retardation layer is the liquid crystal alignment solidification layer described above, the thickness thereof is, for example, 1.0 μm to 2.5 μm. In the present embodiment, the angle formed by the slow axis of the retardation layer and the absorption axis of the polarizing element is preferably 40 ° to 50 °, more preferably 42 ° to 48 °, and even more preferably 44. ° to 46 °. In the present embodiment, the retardation layer preferably exhibits a reverse dispersion wavelength characteristic in which the retardation value increases with the wavelength of the measurement light. In this embodiment, the laminated body is a layer (other retardation layers, shown) arranged between the retardation layer 20 and the second protective film 32 and exhibiting a refractive index characteristic of nz> nz = ny. Can have more).

In another embodiment where the retardation layer 20 is a single layer, the retardation layer 20 can function as a λ / 2 plate. Specifically, the Re (550) of the retardation layer is preferably 200 nm to 300 nm, more preferably 230 nm to 290 nm, and further preferably 230 nm to 280 nm. The thickness of the retardation layer can be adjusted to obtain the desired in-plane retardation of the λ / 2 plate. When the retardation layer is the liquid crystal alignment solidification layer described above, the thickness thereof is, for example, 2.0 μm to 4.0 μm. In the present embodiment, the angle formed by the slow axis of the retardation layer and the absorption axis of the polarizing element is preferably 10 ° to 20 °, more preferably 12 ° to 18 °, still more preferably 12. ° to 16 °.

As shown in FIG. 2, when the retardation layer 20 has a laminated structure, the retardation layer 20 is, for example, the first retardation layer (H layer) 21 and the second retardation layer (Q layer) in order from the polarizing plate side. ) 22 is arranged, and has a two-layer laminated structure. The H layer can typically function as a λ / 2 plate, and the Q layer can typically function as a λ / 4 plate. Specifically, the Re (550) of the H layer is preferably 200 nm to 300 nm, more preferably 220 nm to 290 nm, still more preferably 230 nm to 280 nm; and the Re (550) of the Q layer is preferably. It is 100 nm to 180 nm, more preferably 110 nm to 170 nm, and even more preferably 110 nm to 150 nm. The thickness of the H layer can be adjusted to obtain the desired in-plane phase difference of the λ / 2 plate. When the H layer is the liquid crystal oriented solidified layer described above, the thickness thereof is, for example, 2.0 μm to 4.0 μm. The thickness of the Q layer can be adjusted to obtain the desired in-plane phase difference of the λ / 4 plate. When the Q layer is the liquid crystal oriented solidified layer described above, the thickness thereof is, for example, 1.0 μm to 2.5 μm. In the present embodiment, the angle formed by the slow axis of the H layer and the absorption axis of the stator is preferably 10 ° to 20 °, more preferably 12 ° to 18 °, and even more preferably 12 °. The angle between the slow axis of the Q layer and the absorption axis of the stator is preferably 70 ° to 80 °, more preferably 72 ° to 78 °, and even more preferably 72 °. It is ~ 76 °. When the retardation layer 20 has a laminated structure, each layer (for example, H layer and Q layer) may exhibit a reverse dispersion wavelength characteristic in which the retardation value increases according to the wavelength of the measurement light, and the retardation may be exhibited. It may show a positive wavelength dispersion characteristic in which the value becomes smaller according to the wavelength of the measurement light, or may show a flat wavelength dispersion characteristic in which the phase difference value hardly changes depending on the wavelength of the measurement light.

The retardation layer 20 (each layer in the case of having a laminated structure) typically shows a relationship in which the refractive index characteristic is nx> ny = nz. It should be noted that "ny = nz" includes not only the case where ny and nz are completely equal, but also the case where they are substantially equal. Therefore, ny> nz or ny <nz may occur within a range that does not impair the effect of the present invention. The Nz coefficient of the retardation layer is preferably 0.9 to 1.5, and more preferably 0.9 to 1.3.

As described above, the retardation layer is preferably a liquid crystal oriented solidifying layer. Examples of the liquid crystal compound include a liquid crystal compound (nematic liquid crystal) in which the liquid crystal phase is a nematic phase. As such a liquid crystal compound, for example, a liquid crystal polymer or a liquid crystal monomer can be used. The liquid crystal expression mechanism of the liquid crystal compound may be either lyotropic or thermotropic. 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 and a crosslinkable monomer. This is because the orientation state of the liquid crystal monomer can be fixed by polymerizing or cross-linking (that is, curing) the liquid crystal monomer. After the liquid crystal monomers are oriented, for example, if the liquid crystal monomers are polymerized or crosslinked with each other, the oriented state can be fixed. Here, the polymer is formed by polymerization, and the three-dimensional network structure is formed by crosslinking, but these are non-liquid crystal. Therefore, the formed retardation layer does not undergo a transition to a liquid crystal phase, a glass phase, or a crystal phase due to a temperature change peculiar to a liquid crystal compound, for example. As a result, the retardation layer becomes an extremely stable retardation layer that is not affected by temperature changes.

The temperature range in which the liquid crystal monomer exhibits liquid crystallinity differs depending on the type. Specifically, the temperature range is preferably 40 ° C. to 120 ° C., more preferably 50 ° C. to 100 ° C., and most preferably 60 ° C. to 90 ° C.

As the liquid crystal monomer, any suitable liquid crystal monomer can be adopted. For example, the polymerizable mesogen compounds described in Special Table 2002-533742 (WO00 / 37585), EP358208 (US5211877), EP66137 (US43884553), WO93 / 22397, EP0261712, DE19504224, DE4408171, and GB2280445 can be used. Specific examples of such a polymerizable mesogen compound include, for example, BASF's trade name LC242, Merck's trade name E7, and Wacker-Chem's trade name LC-Silicon-CC3767. As the liquid crystal monomer, a nematic liquid crystal monomer is preferable.

A-3. Relationship between the thickness of the polarizing plate and the retardation layer The total of the thickness of the polarizing plate and the thickness of the retardation layer (sometimes referred to simply as “total thickness”) is 70 μm or less, preferably 50 μm or less. Yes, more preferably 45 μm or less, still more preferably 40 μm or less. With such a total thickness, the above-mentioned warpage problem tends to occur easily. On the other hand, the total thickness is, for example, 25 μm or more.

The ratio of the thickness of the polarizing plate to the thickness of the retardation layer (thickness of the polarizing plate / thickness of the retardation layer, sometimes simply referred to as “thickness ratio”) is, for example, 5 or more, preferably 8 or more. Yes, more preferably 10 or more. At such a thickness ratio, the problem of warpage tends to occur easily. On the other hand, the thickness ratio is preferably 30 or less, more preferably 25 or less.

A-4. First Protective Film The first protective film 31 can be made of any suitable material. Specific examples of the forming material include polyester polymers such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polybutylene terephthalate (PBT); cellulose polymers such as diacetyl cellulose and triacetyl cellulose; polycarbonate polymers; poly. Examples thereof include (meth) acrylic polymers such as methyl methacrylate; and cycloolefin polymers such as polynorbornene; These may be used alone or in combination of two or more.

The thickness of the first protective film is, for example, 10 μm or more and 100 μm or less, preferably 15 μm or more and 90 μm or less, and more preferably 25 μm or more and 80 μm or less.

The first protective film preferably has a moisture permeability of 30 g / ^m 2.24 h or less at 40 ° C. and 92% RH, and more preferably ²⁰ g / m 2.24 h or less. According to such a first protective film, for example, in the humidification treatment described later, moisture can be appropriately imparted to the laminated body (preferably a polarizing element). On the other hand, the moisture permeability of the first protective film at 40 ° C. and 92% RH is, for example, ⁵ g / m 2.24 h or more.

As described above, the first protective film 31 can be attached to the polarizing plate 10 via the pressure-sensitive adhesive layer. Any suitable configuration can be adopted as the pressure-sensitive adhesive layer. Specific examples include acrylic adhesives, rubber adhesives, silicone adhesives, polyester adhesives, urethane adhesives, epoxy adhesives, and polyether adhesives. A pressure-sensitive adhesive having desired characteristics according to the purpose by adjusting the type, number, combination and blending ratio of the monomers forming the base resin of the pressure-sensitive adhesive, as well as the blending amount of the cross-linking agent, the reaction temperature, the reaction time and the like. Can be prepared. The base resin of the pressure-sensitive adhesive may be used alone or in combination of two or more. The base resin is preferably an acrylic resin (specifically, the pressure-sensitive adhesive layer is preferably composed of an acrylic pressure-sensitive adhesive). The thickness of the pressure-sensitive adhesive layer is, for example, 5 μm to 15 μm. The storage elastic modulus of the pressure-sensitive adhesive layer at 25 ° C. is, for example, 1.0 × 10 ⁵ Pa to 1.0 × 10 ⁷ Pa.

In one embodiment, a laminate (hereinafter referred to as “surface protective film”) in which the pressure-sensitive adhesive layer is previously formed on the first protective film is used. The thickness of the surface protective film is preferably 20 μm to 100 μm, and more preferably 30 μm to 90 μm. As described above, when the first protective film is peeled off, it can be peeled off together with the pressure-sensitive adhesive layer (with the surface protective film).

A-5. Second Protective Film The second protective film 32 may be constructed of any suitable plastic film. Specific examples of the plastic film include polyethylene terephthalate (PET) film, polyethylene film, and polypropylene film. As described above, the second protective film 32 can function as a separator. Specifically, as the second protective film 32, a plastic film whose surface is coated with a release agent is preferably used. Specific examples of the release agent include a silicone-based release agent, a fluorine-based release agent, and a long-chain alkyl acrylate-based release agent.

The thickness of the second protective film is, for example, 30 μm or more, preferably 40 μm or more, more preferably 45 μm or more, and further preferably 50 μm or more. On the other hand, the thickness of the second protective film is, for example, 100 μm or less, preferably 80 μm or less.

The ^second protective film preferably has a moisture permeability of 30 g / m 2.24 h or less at 40 ° C. and 92% RH, and more preferably ²⁰ g / m 2.24 h or less. According to such a second protective film, for example, in the humidification treatment described later, moisture can be appropriately imparted to the laminated body (preferably a polarizing element). On the other hand, the moisture permeability of the second protective film at 40 ° C. and 92% RH is, for example, ⁵ g / m 2.24 h or more.

A-6. Preparation of Laminated Body For example, the laminated body 100 is formed by laminating a polarizing plate 10 and a retardation layer 20 to prepare a laminated body precursor, and the obtained laminated body precursor is combined with a first protective film 31 and a second protective film. It can be obtained by laminating 32.

The lamination of the polarizing plate 10 and the retardation layer 20 is performed, for example, while transporting them in a roll (by so-called roll-to-roll). Lamination is typically performed by transferring a liquid crystal oriented solidified layer formed on a substrate. As shown in FIG. 2, when the retardation layer has a laminated structure, each retardation layer may be sequentially laminated (transferred) on the polarizing plate, and the laminate of the retardation layer may be laminated on the polarizing plate (). (Transfer) may be performed.

The transfer is performed, for example, using an active energy ray-curable adhesive. The thickness of the active energy ray-curable adhesive after curing (thickness of the adhesive layer) is, for example, 0.2 μm to 3.0 μm, preferably 0.4 μm to 2.0 μm, and more preferably 0.6 μm. It is ~ 1.5 μm. The warp is caused by, for example, an adhesive used for laminating the polarizing plate and the retardation layer (specifically, shrinkage of the active energy ray-curable adhesive during curing), and the polarizing plate 10 and the retardation layer. Warpage may occur in the laminate precursor obtained by laminating 20 and the laminate.

FIG. 3 is a cross-sectional view showing an example of the warped state of the laminated body precursor. In FIG. 3, hatching is omitted in the cross section of the laminated body precursor in order to make the figure easier to see. In the example shown in FIG. 3, the laminated precursor 90 has a convex warp on the polarizing plate 10 side. Warpage tends to occur along the absorption axis direction of the polarizing plate 10 (polarizer 11).

The lamination of the polarizing plate 10 and the retardation layer 20 is preferably performed in an environment where the amount of water vapor (A1) is 10.2 g / m ³ or less. The amount of water vapor (A1) in the lamination is more preferably 6.0 g / m ³ to 10.0 g / m ³ , and further preferably 8.0 g / m ³ to 9.5 g / m ³ . By laminating in an environment where the amount of water vapor (A1) is in such a range, for example, the effect of the humidification treatment described later becomes remarkable. Such an amount of water vapor (A1) in the lamination can be realized, for example, by changing the relative humidity in the temperature range of 18 ° C. to 25 ° C. depending on the temperature. The amount of water vapor (A1) can be achieved, for example, by setting the relative humidity to 65% RH or less when the temperature is 18 ° C; and also, for example, when the temperature is 20 ° C, the relative humidity. It can be achieved by setting the relative humidity to 55% RH or less; and for example, when the temperature is 23 ° C., it can be realized by setting the relative humidity to 45% RH or less. The lower limit of relative humidity can be, for example, 30% RH.

As mentioned above, if the laminate further comprises other functional layers (eg, conductive layers, other retardation layers), the functional layers may be laminated or formed in predetermined positions in any suitable manner.

The lamination of the laminate precursor having the polarizing plate 10 and the retardation layer 20 and the first protective film 31 is performed, for example, by laminating the surface protective film. The lamination of the laminate precursor and the second protective film 32 is performed, for example, by using an adhesive. The thickness of the pressure-sensitive adhesive (thickness of the pressure-sensitive adhesive layer arranged between the retardation layer 20 and the second protective film 32) is preferably 10 μm to 20 μm.

The laminate can be subjected to a humidification treatment. By subjecting the laminate to a humidifying treatment, moisture is imparted to the laminate (preferably a polarizing element), and the warp generated after the above-mentioned polarizing plate and the retardation layer are laminated can be corrected. It is preferable that the laminated body is not warped during storage described later.

The humidification treatment is performed, for example, by placing the laminate in an environment of 18 ° C. to 34 ° C. and 60% RH to 90% RH. The amount of water vapor (A2) during the humidification treatment is preferably 10.5 g / m ³ to 30 g / m ³ , and more preferably 11 g / m ³ to 20 g / m ³ .

The amount of water vapor (A2) during the humidification treatment can be realized, for example, by setting the relative humidity to 80% RH or more when the temperature is 18 ° C; and for example, when the temperature is 20 ° C. Can be achieved by setting the relative humidity to 60% RH or higher; and for example, when the temperature is 23 ° C., it can be realized by setting the relative humidity to 50% RH or higher. The upper limit of relative humidity can be, for example, 100% RH.

In one embodiment, the laminate is humidified in an environment satisfying a water vapor amount larger than the water vapor amount (A1). More specifically, the difference between the amount of water vapor (A2) during the humidification treatment and the amount of water vapor (A1) is preferably 0.5 g / m ³ or more, and more preferably 1.0 g / m ³ to 28 g. / M3, more preferably 1.0 g / m ³ to 12 g / m ³ , particularly preferably 1.5 g / m ³ to 10 g / m ^{3 , and most preferably 1.5 g / m 3 to} . It is 8 g / m ³ . By humidifying under such conditions, an appropriate amount of water can be imparted to the laminate. More specifically, water can be imparted to the laminate without shrinking the laminate. In the humidification treatment, if the amount of water applied to the laminate is too large, for example, a warp in which the initial warp and the convex direction are opposite to each other and / or a warp in a direction orthogonal to the initial warp direction occurs in the plane. In some cases.

The humidification treatment time is preferably 6 hours or more, more preferably 12 hours or more, and further preferably 18 hours or more. On the other hand, the humidification treatment time is, for example, 48 hours or less.

A-7. Positional Relationship between Polarizer and Laminate In the laminate, the center of the polarizing element in the thickness direction is located within a range of 10% or less of the thickness of half the thickness of the laminate from the center in the thickness direction of the laminate. According to such a positional relationship, it is possible to suppress the occurrence of warpage due to changes in temperature and humidity. As a result, a polarizing plate with a retardation layer in which warpage is suppressed can be obtained. The center in the thickness direction of the polarizing element is preferably located within a range of 8% or less of the thickness of half the thickness of the laminate from the center in the thickness direction of the laminate, and from the center in the thickness direction of the laminate to half of the laminate. It is more preferably located within the range of 4% or less of the thickness.

FIG. 4 is a diagram for explaining the positional relationship between the center of the polarizing element and the center of the laminated body. In FIG. 4, hatching is omitted in some layers of the laminated body in order to make the figure easier to see. The laminate 100 includes a surface protective film 50 including a first protective film 31 and an adhesive layer 52, a polarizing plate 10 including a protective layer 12 and a polarizing element 11, an adhesive layer 54, a first retardation layer 21, and an adhesive layer. 56, a second retardation layer 22, an adhesive layer 58, and a second protective film (separator) 32 are provided in this order. As described above, in the thickness direction, the distance d between the center 11a of the polarizing element 11 and the center 100a of the laminated body 100 is set within a range of 10% or less of half the thickness T of the laminated body 100. In the illustrated example, the center 11a of the polarizing element 11 is located on the retardation layer 21 and 22 side of the center 100a of the laminate 100 in the thickness direction, but is on the protective layer 12 side of the center 100a of the laminate 100. It may be located in. In one embodiment, the position of the center of the stator with respect to the center of the laminate is controlled by adjusting the thickness of the first protective film and the thickness of the second protective film.

B. Method for manufacturing a polarizing plate with a retardation layer The method for manufacturing a polarizing plate with a retardation layer according to one embodiment of the present invention is to prepare the above-mentioned laminate and store (including transport) the laminate. including. Specifically, the laminate is used as a polarizing plate with a retardation layer after storage. According to the above-mentioned laminated body, it is possible to suppress the occurrence of warpage during storage (specifically, due to changes in temperature and humidity). As a result, the obtained polarizing plate with a retardation layer is suppressed in warpage, and can be well laminated on an image display panel, for example.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples. The thickness and the moisture permeability are values measured by the following measuring methods. Unless otherwise specified, "parts" and "%" in Examples and Comparative Examples are based on weight.
<Thickness>
The thickness of 10 μm or less was measured using a scanning electron microscope (manufactured by JEOL Ltd., product name “JSM-7100F”). Thicknesses exceeding 10 μm were measured using a digital micrometer (manufactured by Anritsu, product name “KC-351C”).
<Humidity permeability>
Moisture permeability was determined by the cup method (JIS Z 0208).

[Example 1]
(Manufacturing of polarizing plate)
As the thermoplastic resin base material, an amorphous isophthal copolymerized polyethylene terephthalate film (thickness: 100 μm) having a long shape and a Tg of about 75 ° C. was used, and one side of this resin base material was subjected to corona treatment. ..
100 parts by weight of PVA-based resin in which polyvinyl alcohol (polymerization degree 4200, saponification degree 99.2 mol%) and acetacetyl-modified PVA (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name "Gosefimer") are mixed at a ratio of 9: 1. A PVA aqueous solution (coating solution) was prepared by dissolving 13 parts by weight of potassium iodide in water.
The PVA aqueous solution was applied to the corona-treated surface of the resin base material and dried at 60 ° C. to form a PVA-based resin layer having a thickness of 13 μm, and a laminate was prepared.
The obtained laminate was uniaxially stretched 2.4 times in the vertical direction (longitudinal direction) in an oven at 130 ° C. (aerial auxiliary stretching treatment).
Next, the laminate was immersed in an insolubilizing bath at a liquid temperature of 40 ° C. (a boric acid aqueous solution obtained by blending 4 parts by weight of boric acid with 100 parts by weight of water) for 30 seconds (insolubilization treatment).
Next, in a dyeing bath having a liquid temperature of 30 ° C. (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), the polarizing element finally obtained is charged. It was immersed for 60 seconds while adjusting the concentration so that the single transmittance (Ts) became a desired value (staining treatment).
Then, it was immersed in a cross-linked bath having a liquid temperature of 40 ° C. (a boric acid aqueous solution obtained by blending 3 parts by weight of potassium iodide and 5 parts by weight of boric acid with respect to 100 parts by weight of water) for 30 seconds. (Crossing treatment).
Then, while immersing the laminate in a boric acid aqueous solution (boric acid concentration 4% by weight, potassium iodide concentration 5% by weight) at a liquid temperature of 70 ° C., the total in the longitudinal direction (longitudinal direction) between rolls having different peripheral speeds. Uniaxial stretching was performed so that the stretching ratio was 5.5 times (underwater stretching treatment).
Then, the laminate was immersed in a washing bath having a liquid temperature of 20 ° C. (an aqueous solution obtained by blending 4 parts by weight of potassium iodide with 100 parts by weight of water) (cleaning treatment).
Then, while drying in an oven kept at about 90 ° C., the sauce was brought into contact with a heating roll made of SUS whose surface temperature was kept at about 75 ° C. (dry shrinkage treatment).
In this way, a polarizing element having a thickness of about 5 μm was formed on the resin substrate, and a laminate having a resin substrate / polarizing element configuration was obtained.

An HC-COP film (thickness 27 μm) was attached as a protective layer to the polarizing element side of the obtained laminate via an ultraviolet curable adhesive. The HC-COP film is a film in which an HC layer (thickness 2 μm) is formed on a cycloolefin resin (COP) film (thickness 25 μm), and the COP film is bonded so as to be on the splitter side. Then, the resin base material was peeled off from the polarizing element to obtain a polarizing plate having an HC-COP film (protective layer) / polarizing element.

(Preparation of retardation layer)
10 g of a polymerizable liquid crystal exhibiting a nematic liquid crystal phase (manufactured by BASF: trade name "Pariocolor LC242", represented by the following formula) and a photopolymerization initiator (manufactured by BASF: trade name "Irgacure 907") for the polymerizable liquid crystal compound. ”) 3 g was dissolved in 40 g of toluene to prepare a liquid crystal composition (coating liquid).

The surface of a polyethylene terephthalate (PET) film (thickness 38 μm) was rubbed with a rubbing cloth and subjected to an orientation treatment. The direction of the alignment treatment was set to be 15 ° when viewed from the visual recognition side with respect to the direction of the absorption axis of the polarizing element when the polarizing plate was attached. The liquid crystal coating liquid was applied to the alignment-treated surface with a bar coater, and the liquid crystal compound was oriented by heating and drying at 90 ° C. for 2 minutes. The liquid crystal layer thus formed is irradiated with light of 1 mJ / cm ² using a metal halide lamp to cure the liquid crystal layer, whereby a liquid crystal oriented solidified layer A (H layer) is formed on the PET film. did. The thickness of the liquid crystal oriented solidified layer A was 2.5 μm, and the in-plane retardation Re (550) was 270 nm. Further, the liquid crystal oriented solidified layer A showed a refractive index characteristic of nx> ny = nz.

On the PET film in the same manner as above, except that the coating thickness was changed and the orientation processing direction was set to be 75 ° when viewed from the visual side with respect to the direction of the absorber's absorption axis. A liquid crystal oriented solidified layer B (Q layer) was formed. The thickness of the liquid crystal oriented solidified layer B was 1.5 μm, and the in-plane retardation Re (550) was 140 nm. Further, the liquid crystal oriented solidified layer B exhibited a refractive index characteristic of nx> ny = nz.

(Preparation of laminated body)
The obtained liquid crystal oriented solidified layer A (H layer) and the liquid crystal oriented solidified layer B (Q layer) were transferred in this order to the polarizing element side of the obtained polarizing plate. At this time, the angle between the absorption axis of the splitter and the slow axis of the oriented solidification layer A is 15 °, and the angle between the absorption axis of the splitter and the slow axis of the oriented solidification layer B is 75 °. Transferred (bonded). The transfer of the liquid crystal oriented solidified layer A (H layer) was performed via an ultraviolet curable adhesive (thickness 0.5 μm). The transfer of the liquid crystal oriented solidified layer B (Q layer) was performed via an ultraviolet curable adhesive (thickness 1.5 μm). In this way, a laminated precursor was obtained. The transfer was performed while transporting the rolls. Further, the transfer was carried out in an environment with a water vapor content of 9.3 g / m ³ (23 ° C. and 45% RH).
The total thickness of the obtained laminated precursor was 36 μm, and the thickness ratio was 8.

The obtained elongated laminate precursor was cut along the direction of 45 ° with respect to the longitudinal direction and the width direction (direction orthogonal to the longitudinal direction), and a 165 mm × 80 mm single-wafer laminate precursor was cut. Got The longitudinal direction corresponds to the absorption axis direction of the substituent.

Next, a surface protective film (thickness 48 μm) was attached to the protective layer side of the polarizing plate of the laminate precursor. The surface protective film is a PET-based film (thickness 38 μm, moisture permeability 18 g / ^m 2.24 h) on which an adhesive layer (thickness 10 μm) is formed.
Further, (PET film, thickness 50 μm, moisture permeability 13 g / ^m 2.24 h) is bonded to the liquid crystal oriented solidified layer B (Q layer) side of the laminate precursor via an adhesive layer (thickness 15 μm). , A single-wafer-shaped laminate having a size of 165 mm × 80 mm was obtained.

(Humidification treatment)
The obtained single-wafer-like laminate was placed in an environment of 23 ° C. and 60% RH (water vapor amount was 12.4 g / m ³ ) for 24 hours to correct the warp generated in the laminate precursor.

[Example 2]
In the production of the laminate, a surface protective film having a thickness of 60 μm (PET film (thickness 50 μm, moisture permeability 13 g / ^m 2.24 h) and an adhesive layer (thickness 10 μm)) was placed on the protective layer side of the polarizing plate of the laminate precursor. A laminated body was obtained in the same manner as in Example 1 except that the film on which the above was formed was bonded.

[Example 3]
In the production of the laminate, a surface protective film having a thickness of 60 μm (PET film (thickness 50 μm, moisture permeability 13 g / ^m 2.24 h) and an adhesive layer (thickness 10 μm)) is placed on the protective layer side of the polarizing plate of the laminate precursor. A separator (PET film, thickness 75 μm, moisture permeability 10 g / ^m 2.24 h) was attached to the liquid crystal oriented solidified layer B (Q layer) side of the laminate precursor. A laminated body was obtained in the same manner as in Example 1 except that the film was bonded via a pressure-sensitive adhesive layer (thickness: 15 μm).

[Example 4]
In the production of the laminate, a surface protective film having a thickness of 85 μm (PET film (thickness 75 μm, moisture permeability 10 g / ^m 2.24 h) and an adhesive layer (thickness 10 μm)) is placed on the protective layer side of the polarizing plate of the laminate precursor. A separator (PET film, thickness 75 μm, moisture permeability 10 g / ^m 2.24 h) was attached to the liquid crystal oriented solidified layer B (Q layer) side of the laminate precursor. A laminated body was obtained in the same manner as in Example 1 except that the film was bonded via a pressure-sensitive adhesive layer (thickness: 15 μm).

[Comparative Example 1]
In the production of the laminate, a separator (PET film, thickness 38 μm, moisture permeability 18 g / ^m 2.24 h) is attached to the liquid crystal oriented solidified layer B (Q layer) side of the laminate precursor, and an adhesive layer (thickness 15 μm) is applied. A laminated body was obtained in the same manner as in Example 1 except that the laminates were bonded to each other.

[Comparative Example 2]
In the production of the laminate, a separator (PET film, thickness 75 μm, moisture permeability 10 g / ^m 2.24 h) is attached to the liquid crystal oriented solidified layer B (Q layer) side of the laminate precursor, and an adhesive layer (thickness 15 μm) is applied. A laminated body was obtained in the same manner as in Example 1 except that the laminates were bonded to each other.

[Comparative Example 3]
In the production of the laminate, a surface protective film having a thickness of 60 μm (PET film (thickness 50 μm, moisture permeability 13 g / ^m 2.24 h) and an adhesive layer (thickness 10 μm)) is placed on the protective layer side of the polarizing plate of the laminate precursor. A separator (PET film, thickness 38 μm, moisture permeability 18 g / ^m 2.24 h) was attached to the liquid crystal oriented solidified layer B (Q layer) side of the laminate precursor. A laminated body was obtained in the same manner as in Example 1 except that the film was bonded via a pressure-sensitive adhesive layer (thickness: 15 μm).

[Comparative Example 4]
In the production of the laminate, a surface protective film having a thickness of 85 μm (PET film (thickness 75 μm, moisture permeability 10 g / ^m 2.24 h) and an adhesive layer (thickness 10 μm)) is placed on the protective layer side of the polarizing plate of the laminate precursor. A separator (PET film, thickness 38 μm, moisture permeability 18 g / ^m 2.24 h) was attached to the liquid crystal oriented solidified layer B (Q layer) side of the laminate precursor. A laminated body was obtained in the same manner as in Example 1 except that the film was bonded via a pressure-sensitive adhesive layer (thickness: 15 μm).

[Comparative Example 5]
In the production of the laminate, a surface protective film having a thickness of 85 μm (PET film (thickness 75 μm, moisture permeability 10 g / ^m 2.24 h) and an adhesive layer (thickness 10 μm)) is placed on the protective layer side of the polarizing plate of the laminate precursor. A separator (PET film, thickness 50 μm, moisture permeability 13 g / ^m 2.24 h) was attached to the liquid crystal oriented solidified layer B (Q layer) side of the laminate precursor. A laminated body was obtained in the same manner as in Example 1 except that the film was bonded via a pressure-sensitive adhesive layer (thickness: 15 μm).

<Evaluation>
The humidified laminates of each Example and Comparative Example were stored in an environment of 23 ° C. and 55% RH for 48 hours, and the change in warpage before and after storage was measured.
Specifically, a test piece having a size of 140 mm × 70 mm was cut out from the laminated body. At this time, the stator was cut out so that the absorption axis direction was the long side direction. The height of the highest portion from the flat surface was measured when the cut-out test piece was placed on a flat surface so that the separator side was on the flat surface side, and the amount of warpage was determined. Here, the case where the warp is convex on the stationary surface side is defined as "positive (+)", and the case where the warp is convex on the opposite side to the stationary surface is defined as "negative (-)". Next, the difference between the amount of warpage of the laminated body before storage and the amount of warpage of the laminated body after storage was determined.
The evaluation results are summarized in Table 1 together with the center position of the modulator. The center position (%) of the polarizing element in Table 1 is determined by the formula: d ÷ using the distance d between the center of the polarizing element and the center of the laminated body in the thickness direction and the thickness T of the laminated body shown in FIG. It is obtained by (T / 2) × 100. The change in warpage (mm) in Table 1 is an average value of three measurement samples.

As is clear from Table 1, in the examples, the change in warpage is small. Specifically, the corrected state of the warp generated in the laminated body precursor is well maintained.

The polarizing plate with a retardation layer according to one embodiment of the present invention is used as a polarizing plate with a retardation layer of an image display device, and in particular, an image display device that is curved, bent, folded, or windable. Can be suitably used for. Typical examples of the image display device include a liquid crystal display device, an organic EL display device, and an inorganic EL display device.

10 Polarizing plate 11 Polarizer 11a Center of splitter 12 Protective layer 20 Phase difference layer 21 First phase difference layer (H layer)
22 Second phase difference layer (Q layer)
31 First protective film 32 Second protective film 90 Laminated precursor 100 Laminated 100a Center of laminated body

Claims (12)

With the first protective film,
A polarizing plate including a polarizing element and a protective layer arranged on at least one side of the polarizing element.
With the retardation layer,
A laminate having a second protective film in this order,
The total of the thickness of the polarizing plate and the thickness of the retardation layer is 70 μm or less.
The center of the polarizing element in the thickness direction is located within a range of 10% or less of the thickness of half the thickness of the laminate from the center of the laminate in the thickness direction.
Laminated body. The laminate according to claim 1, wherein the ratio of the thickness of the polarizing plate to the thickness of the retardation layer is 5 or more. The laminate according to claim 1 or 2, wherein the polarizing plate has a protective layer arranged only on the side of the polarizing element on which the retardation layer is not arranged. The laminate according to any one of claims 1 to 3, wherein the retardation layer is an orientation-solidified layer of a liquid crystal compound. The laminate according to any one of claims 1 to 4, wherein the thickness of the first protective film is 15 μm or more and 90 μm or less. The laminate according to any one of claims 1 to 5, wherein the thickness of the second protective film is 40 μm or more. Preparing the laminate according to any one of claims 1 to 6 and
To store the laminate,
A method for manufacturing a polarizing plate with a retardation layer. The manufacturing method according to claim 7, wherein the polarizing plate and the retardation layer are laminated to obtain a laminated body precursor. The production method according to claim 8, which comprises cutting the laminate precursor into a single-wafer shape. The production method according to any one of claims 7 to 9, which comprises laminating the polarizing plate and the retardation layer using an active energy ray-curable adhesive. The production method according to claim 10, wherein the thickness of the active energy ray-curable adhesive after curing is 0.4 μm or more. The production method according to any one of claims 7 to 11, which comprises subjecting the laminate to a humidifying treatment before storage.

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