Method for manufacturing laminates and polarizing plates with phase retardation layers

Abstract

This invention provides a polarizing plate with a phase retardation layer that suppresses warping. An embodiment of this invention comprises, in sequence: a first protective film, a polarizing plate including a polarizing element and a protective layer disposed on at least one side of the polarizing element, a phase retardation layer, and a second protective film. The combined thickness of the polarizing plate and the phase retardation layer is 70 μm or less, and the center of the polarizing element in the thickness direction is located within a range of less than 10% of half the thickness of the stacked body from the center in the thickness direction.

Description

Technical Field

[0001] This invention relates to a method for manufacturing a laminate and a polarizing plate with a phase retardation layer. Prior Technology

[0002] Image display devices, represented by liquid crystal displays and electroluminescent (EL) displays (e.g., organic EL displays and inorganic EL displays), are rapidly gaining popularity. Image display devices typically utilize polarizing plates and retardation plates. In practical applications, polarizing plates with an integral retardation layer, integrating the polarizing plate and retardation plate, are widely used (e.g., Patent Document 1). In recent years, research has been conducted on the possibility of using flexible substrates (e.g., resin substrates) to achieve bending, folding, and rolling of image display devices. As a polarizing plate with an retardation layer for such image display devices, a thin polarizing plate with an retardation layer is required. However, thin polarizing plates with an retardation layer are prone to warping. [Previous Technical Documents] [Patent Literature]

[0003] [Patent Document 1] Japanese Patent No. 3325560 Summary of the Invention

[0004] [The problem the invention aims to solve] [ ] The present invention was made to solve the aforementioned problems, and its main objective is to provide a polarizing plate with a phase difference layer that suppresses warping. [Technical means to solve the problem]

[0005] According to an embodiment of the present invention, a laminate is provided. The laminate sequentially comprises: a first protective film, a polarizing plate including a polarizing element and a protective layer disposed on at least one side of the polarizing element, a retardation layer, and a second protective film, wherein the combined thickness of the polarizing plate and the retardation layer is 70 μm or less, and the center of the polarizing element in the thickness direction is located within a range of less than 10% of half the thickness of the laminate from the center of the laminate in the thickness direction. In one embodiment, the ratio of the thickness of the polarizing plate to the thickness of the phase retardation layer is 5 or more. In one embodiment, in the polarizing plate, a protective layer is provided only on the side of the polarizing element where the phase difference layer is not disposed. In one embodiment, the phase retardation layer is an alignment and curing 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, a method for manufacturing a polarizing plate with a phase retardation layer is provided. The manufacturing method includes: preparing the aforementioned laminate; and storing the aforementioned laminate. In one embodiment, the manufacturing method includes: depositing the polarizing plate and the phase difference layer to obtain a laminate precursor. In one embodiment, the manufacturing method includes cutting the laminate precursor into a single sheet. In one embodiment, the manufacturing method includes: laminating the polarizing plate and the phase difference layer using an active energy line hardening adhesive. In one embodiment, the thickness of the above-mentioned active energy line curing adhesive after curing is 0.4 μm or more. In one embodiment, the manufacturing method includes: humidifying the laminate before storage. [Effects of the Invention]

[0006] According to an embodiment of the present invention, by positioning the center of the polarizing element within a specific range in a laminate having a polarizing plate and a retardation layer, a polarizing plate with a retardation layer whose warpage is suppressed can be obtained. Simple Explanation of the Diagram

[0007] Figure 1 is a schematic cross-sectional view showing the schematic structure of the laminate according to the first embodiment of the present invention. Figure 2 is a schematic cross-sectional view showing the schematic structure of the laminate according to the second embodiment of the present invention. Figure 3 is a cross-sectional view showing an example of the warped state of a laminate precursor. Figure 4 is a diagram used to illustrate the positional relationship between the center of the polarizing element and the center of the laminate. Implementation

[0008] The following describes embodiments of the present invention, but the present invention is not limited to these embodiments.

[0009] (Definitions of terms and symbols) The definitions of terms and symbols used in this specification are as follows. (1) Refractive index (nx, ny, nz) "nx" refers to the refractive index in the direction where the in-plane refractive index is the maximum (i.e., the direction of the late phase axis), "ny" refers to the refractive index in the direction orthogonal to the late phase axis in the plane (i.e., the direction of the advanced phase axis), and "nz" refers to the refractive index in the thickness direction. (2) In-plane phase difference (Re) "Re(λ)" is the in-plane phase difference measured at 23°C using light with a wavelength of λ nm. For example, "Re(550)" is the in-plane phase difference measured at 23°C using light with a wavelength of 550 nm. When the thickness of the layer (film) is set as d (nm), Re(λ) can be obtained by the formula Re(λ)=(nx-ny)×d. (3) Phase difference (Rth) in the thickness direction "Rth(λ)" is the phase difference in the thickness direction measured at 23°C using light with a wavelength of λnm. For example, "Rth(550)" is the phase difference in the thickness direction measured at 23°C using light with a wavelength of 550 nm. When the thickness of the layer (film) is set as d (nm), Rth(λ) can be obtained by the formula Rth(λ)=(nx-nz)×d. (4) Nz coefficient The Nz coefficient can be obtained by Nz=Rth / Re. (5) Angle When referring to angles in this specification, the angle includes both clockwise and counterclockwise directions relative to a reference direction. Therefore, for example, "45°" refers to ±45°.

[0010] A method for manufacturing a polarizing plate with a phase retardation layer according to one embodiment of the present invention includes: preparing a laminate having a polarizing plate containing polarizing elements and a phase retardation layer; and placing the laminate in a specific environment for humidification treatment.

[0011] A. Laminated body Figure 1 is a schematic cross-sectional view showing the schematic configuration of a laminate according to a first embodiment of the present invention. The laminate 100, from the viewing side, sequentially includes a first protective film 31, a polarizing plate 10, a retardation layer 20, and a second protective film 32. In the example shown, the polarizing plate 10 includes a polarizing element 11 and a protective layer 12 disposed on the viewing side of the polarizing element 11 (the side without the retardation layer 20), and no protective layer is disposed between the polarizing element 11 and the retardation layer 20. According to this configuration, for example, the following polarizing plate thickness, total thickness, and thickness ratio can be well achieved.

[0012] Although not shown in the figure, a protective layer may be further included on the other side of the polarizing element 11 (between the polarizing element 11 and the phase difference layer 20).

[0013] Figure 2 is a schematic cross-sectional view showing the schematic structure of the laminate according to the second embodiment of the present invention. In the first embodiment described above, the phase retardation layer 20 is considered as a single layer. In contrast, in the second embodiment, the phase retardation layer 20 has a laminated structure including a first phase retardation layer 21 and a second phase retardation layer 22. Alternatively, unlike the example in the figure, the phase retardation layer 20 may have a laminated structure with three or more layers.

[0014] Although not illustrated, the laminate may further have other functional layers. The types, characteristics, number, combination, and configuration of the functional layers that the laminate may 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 attached. The conductive layer or the isotropic substrate with a conductive layer is typically disposed between the retardation layer 20 and the second protective film 32. Furthermore, a laminate with a conductive layer or an isotropic substrate with a conductive layer (a polarizing plate with a retardation layer) is used, for example, in an image display device in which a touch sensor is assembled inside an image display panel. As another example, the laminate may further have other retardation layers. The optical characteristics (e.g., refractive index characteristics, in-plane retardation, Nz coefficient, photoelastic coefficient), thickness, and configuration of the other retardation layers can be appropriately set according to the purpose. As a specific example, other phase retardation layers (typically layers that impart (elliptical) polarization or provide ultra-high phase retardation) can be provided on the viewing side of the polarizing element 11 to improve visibility when viewed through polarized sunglasses. With such layers, excellent visibility can be achieved even when viewing the displayed image through polarized lenses such as polarized sunglasses. Therefore, the resulting polarizing plate with a phase retardation layer can also be suitable for use in image display devices that can be used outdoors.

[0015] The components constituting the laminate can be laminated via any suitable adhesive layer (not shown). Specific examples of adhesive layers include adhesive layers and bonding agents. For example, the first protective film 31 is attached to the polarizing plate 10 via an adhesive layer. The first protective film 31 can be retained until the polarizing plate with the phase retardation layer obtained by means of the present invention is put into use (before being laminated to the image display panel), or it can be peeled off during the manufacturing process of the final product (image display device), or it can be directly mounted on the final product.

[0016] For example, the second protective film 32 can be adhered to the retardation layer 20 via an adhesive layer. In practice, the second protective film 32 can function as a temporarily adhered release film (isolation film) before the polarizing plate with the retardation layer obtained by means of the embodiments of the present invention is put into use. By temporarily adhering the release film, for example, the adhesive layer can be protected and a roll of laminate can be formed.

[0017] For example, the retardation layer 20 is bonded to the polarizing plate 10 via an adhesive layer (preferably using an active energy line curing adhesive). When the retardation layer 20 has a multilayer structure with two or more layers, each retardation layer is bonded together via an adhesive layer (preferably using an active energy line curing adhesive).

[0018] A-1.Polarizing plate The aforementioned polarizing plate includes a polarizing element and a protective layer. The thickness of the polarizing plate also depends on the number of protective layers included, but is preferably 20 μm or more, more preferably 25 μm or more. On the other hand, the thickness of the polarizing plate is preferably 40 μm or less, more preferably 36 μm or less, and even more preferably 33 μm or less. Furthermore, regarding the thickness of the polarizing plate, when an adhesive layer (e.g., an adhesive layer) is used when laminating the polarizing element and the protective layer, the thickness does not include the thickness of the adhesive layer.

[0019] The aforementioned polarizing element is typically a resin film containing a dichroic substance (e.g., iodine). Examples of resin films include hydrophilic polymer films such as polyvinyl alcohol (PVA) films, partially formalized PVA films, and partially saponified ethylene-vinyl acetate copolymer films.

[0020] The thickness of the polarizing element is preferably 15 μm or less, more preferably 12 μm or less, and even more preferably 10 μm or less. On the other hand, the thickness of the polarizing element is preferably 1 μm or more.

[0021] The polarizing element preferably exhibits absorption dichroism at any wavelength within the range of 380 nm to 780 nm. The transmittance of the polarizing element is, for example, 41.5% to 46.0%, more preferably 42.0% to 46.0%, and even more preferably 44.5% to 46.0%. The polarization degree of the polarizing element is preferably 97.0% or higher, even more preferably 99.0% or higher, and even more preferably 99.9% or higher.

[0022] The aforementioned protective layer can be formed from any suitable film capable of serving as a protective layer for a polarizing element. Specific examples of materials that constitute the main component of such a film include: cellulose resins such as triacetyl cellulose (TAC), polyester resins, polyvinyl alcohol resins, polycarbonate resins, polyamide resins, polyimide resins, polyether resins, polyurethane resins, polystyrene resins, cycloolefin resins such as polynorcamphene, polyolefin resins, (meth)acrylic acid resins, acetate resins, and the like.

[0023] A polarizing plate with a phase décor layer obtained by means of an embodiment of the present invention is typically disposed on the viewing side of an image display device, and a protective layer 12 is disposed on the viewing side. Therefore, the protective layer 12 can be subjected to surface treatments such as hard coating (HC), anti-reflection treatment, anti-adhesion treatment, and anti-glare treatment as needed.

[0024] 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. Furthermore, when the above-mentioned surface treatment has been performed, the thickness of the protective layer 12 includes the thickness of the surface treatment layer.

[0025] In one embodiment, the protective layer (not shown) disposed between the polarizing element 11 and the retardation layer 20 is preferably optically isotropic. In this specification, "optically isotropic" means that the in-plane phase difference Re(550) is 0 nm to 10 nm, and the phase difference Rth(550) in the thickness direction is -10 nm to +10 nm. The thickness of the protective layer disposed 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 even more preferably 10 μm to 30 μm.

[0026] Polarizing plates can be manufactured by any suitable method. Specifically, a polarizing plate may include a polarizing element made of a single layer of resin film, or it may include a polarizing element obtained by using two or more layers of laminate.

[0027] A representative method for manufacturing a polarizing element from the aforementioned single-layer resin film includes: subjecting the resin film to a dyeing treatment using dichroic substances such as iodine or dichroic dyes, and a stretching treatment. As mentioned above, the resin film can be, for example, a hydrophilic polymer film such as a polyvinyl alcohol (PVA) film, a partially formalized PVA film, or an ethylene-vinyl acetate copolymer partially saponified film. The method may further include insolubility treatment, swelling treatment, crosslinking treatment, etc. By applying a protective layer to at least one area layer of the obtained polarizing element, a polarizing plate can be obtained. This manufacturing method is well-known and commonly used in the art, therefore detailed description is omitted.

[0028] As a specific example of a polarizing element obtained using the above-described laminate, examples include: a polarizing element obtained using a resin substrate and a laminate of a PVA-based resin layer (PVA-based resin film) deposited on the resin substrate, or a polarizing element obtained using a resin substrate and a laminate coated with a PVA-based resin layer formed on the resin substrate. A polarizing element obtained using a resin substrate and a laminate coated with a PVA-based resin layer formed on the resin substrate can be manufactured, for example, by: coating a PVA-based resin solution onto a resin substrate and drying it to form a PVA-based resin layer on the resin substrate, thus obtaining a laminate of the resin substrate and the PVA-based resin layer; stretching and dyeing the laminate to form a polarizing element from the PVA-based resin layer. In this embodiment, it is preferable to form a polyvinyl alcohol-based resin layer comprising a halide and a polyvinyl alcohol-based resin on one side of the resin substrate. Stretching typically includes immersing the laminate in an aqueous boric acid solution for stretching. Furthermore, the stretching can be further enhanced as needed by subjecting the laminate to aerial stretching at a high temperature (e.g., above 95°C) before stretching in a boric acid aqueous solution. Additionally, in this embodiment, it is preferable to subject the laminate to a drying shrinkage treatment, which involves heating it while transporting it in the length direction, causing it to shrink by more than 2% in the width direction. Typically, the manufacturing method of this embodiment includes sequentially performing aerial assisted stretching, dyeing, underwater stretching, and drying shrinkage treatments on the laminate. By introducing assisted stretching, even when PVA is coated onto a thermoplastic resin, the crystallinity of PVA can be improved, achieving higher optical properties. Furthermore, by simultaneously improving the alignment of PVA beforehand, problems such as reduced alignment or dissolution of PVA can be prevented when immersed in water during subsequent dyeing or stretching steps, achieving higher optical properties. Moreover, when the PVA-based resin layer is immersed in a liquid, compared to the case where the PVA-based resin layer does not contain halides, the disordered alignment and reduced alignment of polyvinyl alcohol molecules can be suppressed. This improves the optical properties of the polarizing element obtained by immersing the laminate in a liquid through dyeing and water-stretching processes. Furthermore, by shrinking the laminate in the width direction through a drying shrinkage process, optical properties are further enhanced. The resulting resin substrate / polarizing element laminate can be used directly (i.e., the resin substrate can be used as a protective layer for the polarizing element), or the resin substrate can be peeled off from the resin substrate / polarizing element laminate and used as any suitable protective layer on the peeled surface or the opposite side of the peeled surface. Detailed descriptions of this method for manufacturing polarizing elements are provided, for example, in Japanese Patent Application Publication No. 2012-73580 and Japanese Patent No. 6470455. The entire contents of these publications are incorporated herein by reference.

[0029] A-2. Phase Difference Layer The thickness of the aforementioned retardation layer also depends on its composition (whether it is a single layer or has a multilayer structure), but it is preferably 8 μm or less, more preferably 5 μm or less. On the other hand, the thickness of the retardation layer may be, for example, 1 μm or more. Furthermore, when the retardation layer has a multilayer structure, the "thickness of the retardation layer" refers to the total thickness of each retardation layer. Specifically, the "thickness of the retardation layer" does not include the thickness of the adhesive layer (e.g., the adhesive layer).

[0030] As the aforementioned retardation layer, an alignment-cured layer using a liquid crystal compound (liquid crystal alignment-cured layer) is preferred. By using a liquid crystal compound, the difference between nx and ny in the obtained retardation layer can be significantly increased compared to non-liquid crystal materials, thus significantly reducing the thickness of the retardation layer used to obtain the desired in-plane retardation. Therefore, a significant reduction in the thinness of the polarizer with the retardation layer can be achieved. In this specification, "alignment-cured layer" refers to a layer in which the liquid crystal compound is aligned in a specific direction within the layer, and its alignment state has been fixed. Furthermore, the concept of "alignment-cured layer" includes alignment-cured layers obtained by curing liquid crystal monomers as described below. In the retardation layer, representatively, rod-shaped liquid crystal compounds are aligned in a state of alignment along the lag axis direction of the retardation layer (horizontal alignment).

[0031] The aforementioned liquid crystal alignment and curing layer can be formed by performing an alignment treatment on the surface of a specific substrate, coating the surface with a coating liquid containing a liquid crystal compound, aligning the liquid crystal compound in a direction corresponding to the alignment treatment, and fixing the alignment state. The alignment treatment can be any suitable method. Specifically, examples include: mechanical alignment treatment, physical alignment treatment, and chemical alignment treatment. Specific examples of mechanical alignment treatment include: friction treatment and stretching treatment. Specific examples of physical alignment treatment include: magnetic field alignment treatment and electric field alignment treatment. Specific examples of chemical alignment treatment include: oblique evaporation and photoalignment treatment. The processing conditions for each alignment treatment can be any suitable method depending on the purpose.

[0032] The alignment of liquid crystal compounds is performed by processing them at a temperature suitable for displaying liquid crystal phases, depending on the type of liquid crystal compound. Through this temperature treatment, the liquid crystal compound exhibits a liquid crystal state, and is aligned accordingly with the alignment treatment direction of the substrate surface.

[0033] In one embodiment, the alignment state is fixed by cooling the liquid crystal compound aligned as described above. When the liquid crystal compound is a polymerizable monomer or a crosslinking monomer, the alignment state is fixed by performing a polymerization or crosslinking treatment on the liquid crystal compound aligned as described above.

[0034] Specific examples of liquid crystal compounds and detailed methods for forming alignment and curing layers are described in Japanese Patent Application Publication No. 2006-163343. The contents of that publication are incorporated herein by reference.

[0035] As mentioned above, the phase difference layer 20 can be a single layer or have a stacked structure of two or more layers.

[0036] As shown in Figure 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 even more preferably 110 nm to 160 nm. The thickness of the retardation layer can be adjusted to obtain the desired in-plane phase difference of the λ / 4 plate. When the retardation layer is the aforementioned liquid crystal alignment and curing layer, its thickness is, for example, 1.0 μm to 2.5 μm. In this embodiment, the angle between the late phase 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 this embodiment, the retardation layer preferably exhibits inverse wavelength dispersion characteristics, where the phase difference value increases accordingly with the wavelength of the measurement light. Furthermore, in this embodiment, the laminate may further have a layer disposed between the retardation layer 20 and the second protective film 32 that exhibits refractive index characteristics of nz>nx=ny (other retardation layers, not shown).

[0037] 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 even more preferably 230 nm to 280 nm. The thickness of the retardation layer can be adjusted to obtain the desired in-plane phase difference of the λ / 2 plate. When the retardation layer is the liquid crystal alignment and curing layer described above, its thickness is, for example, 2.0 μm to 4.0 μm. In this embodiment, the angle between the late phase axis of the retardation layer and the absorption axis of the polarizing element is preferably 10° to 20°, more preferably 12° to 18°, and even more preferably 12° to 16°.

[0038] As shown in FIG. 2, when the retardation layer 20 has a laminated structure, the retardation layer 20 has, for example, a two-layer laminated structure. That is, a first retardation layer (H layer) 21 and a second retardation layer (Q layer) 22 are arranged in order from the polarizing plate side. The H layer can typically function as a λ / 2 plate, and the Q layer can typically function as a λ / 4 plate. Specifically, Re(550) of the H layer is preferably 200 nm to 300 nm, more preferably 220 nm to 290 nm, and still more preferably 230 nm to 280 nm; Re(550) of the Q layer is preferably 100 nm to 180 nm, more preferably 110 nm to 170 nm, and still more preferably 110 nm to 150 nm. The thickness of the H layer can be adjusted in such a way as to obtain the desired in-plane retardation of the λ / 2 plate. When the H layer is the above-mentioned liquid crystal alignment cured layer, its thickness is, for example, 2.0 μm to 4.0 μm. The thickness of the Q layer can be adjusted in such a way as to obtain the desired in-plane retardation of the λ / 4 plate. When the Q layer is the above-mentioned liquid crystal alignment cured layer, its thickness 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 polarizing element is preferably 10° to 20°, more preferably 12° to 18°, and still more preferably 12° to 16°; the angle formed by the slow axis of the Q layer and the absorption axis of the polarizing element is preferably 70° to 80°, more preferably 72° to 78°, and still more preferably 72° to 76°. When the retardation layer 20 has a laminated structure, each layer (for example, the H layer and the Q layer) can exhibit an inverse wavelength dispersion characteristic in which the retardation value increases correspondingly with the wavelength of the measurement light, can exhibit a positive wavelength dispersion characteristic in which the retardation value decreases correspondingly with the increase in the wavelength of the measurement light, or can exhibit a flat wavelength dispersion characteristic in which the retardation value hardly changes with the wavelength of the measurement light.

[0039] Regarding the retardation layer 20 (each layer when having a laminated structure), typically, the refractive index characteristics exhibit a relationship of nx > ny = nz. Furthermore, "ny = nz" includes not only the case where ny and nz are exactly equal but also the case where they are substantially equal. Therefore, within the scope of not impairing the effects of the present invention, there can be cases where ny > nz or ny < nz. The Nz coefficient of the retardation layer is preferably 0.9 to 1.5, more preferably 0.9 to 1.3.

[0040] As described above, the retardation layer is preferably a liquid crystal alignment cured layer. As the above-mentioned liquid crystal compound, for example, a liquid crystal compound having a nematic liquid crystal phase (nematic liquid crystal) can be cited. As such a liquid crystal compound, for example, a liquid crystal polymer or a liquid crystal monomer can be used. The mechanism for expressing the liquid crystallinity of the liquid crystal compound can be lyotropic or thermotropic. The liquid crystal polymer and the liquid crystal monomer can be used alone or in combination.

[0041] When the liquid crystal compound is a liquid crystal monomer, the liquid crystal monomer is preferably a polymerizable monomer or a crosslinking monomer. This is because the alignment state of the liquid crystal monomer can be fixed by polymerizing or crosslinking (i.e., hardening). If, after aligning the liquid crystal monomers, they are then polymerized or crosslinked, this alignment state can be fixed. Here, polymerization forms a polymer, and crosslinking forms a three-dimensional network structure, but these are non-liquid crystals. Therefore, the resulting retardation layer will not, for example, shift to the liquid crystal phase, glass phase, or crystalline phase due to temperature changes characteristic of liquid crystal compounds. As a result, the retardation layer becomes a retardation layer with extremely excellent stability, unaffected by temperature changes.

[0042] The temperature range for liquid crystal display properties varies depending on the type of liquid crystal. Specifically, the preferred temperature range is 40°C to 120°C, a further preferred range is 50°C to 100°C, and the optimal range is 60°C to 90°C.

[0043] The aforementioned liquid crystal monomer can be any suitable liquid crystal monomer. For example, polymerizable liquid crystal precursor compounds described in Japanese Patent Publication No. 2002-533742 (WO00 / 37585), EP358208 (US5211877), EP66137 (US4388453), WO93 / 22397, EP0261712, DE19504224, DE4408171, and GB2280445 can be used. Specific examples of such polymerizable liquid crystal precursor compounds include BASF's trade name LC242, Merck's trade name E7, and Wacker-Chem's trade name LC-Sillicon-CC3767. Nematic liquid crystal monomers are preferred.

[0044] A-3. Relationship between the thickness of the polarizing plate and the phase retardation layer The total thickness of the polarizing plate and the retardation layer (sometimes simply referred to as the "total thickness") is 70 μm or less, preferably 50 μm or less, more preferably 45 μm or less, and even more preferably 40 μm or less. With such a total thickness, there is a tendency for the aforementioned warping problem to easily occur. On the other hand, the total thickness is, for example, 25 μm or more.

[0045] The ratio of the thickness of the polarizing plate to the thickness of the retardation layer (thickness of polarizing plate / thickness of retardation layer, sometimes simply referred to as "thickness ratio") is, for example, 5 or more, preferably 8 or more, and even more preferably 10 or more. With such a thickness ratio, there is a tendency to easily cause the aforementioned warping problem. On the other hand, a thickness ratio of 30 or less is preferred, and more preferably 25 or less.

[0046] A-4. First protective film The first protective film 31 can be formed from any suitable material. Specific examples of forming materials include: polyester polymers such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polybutylene terephthalate (PBT); cellulose polymers such as diacetylcellulose and triacetylcellulose; polycarbonate polymers; (meth)acrylic polymers such as polymethyl methacrylate; and cyclic olefin polymers such as polynorcamphene. These materials can be used alone or in combination of two or more.

[0047] The thickness of the first protective film is, for example, 10 μm to 100 μm, preferably 15 μm to 90 μm, and even more preferably 25 μm to 80 μm.

[0048] The first protective film preferably has a moisture permeability of 30 g / m²·24 h or less, and more preferably 20 g / m²·24 h or less, at 40°C and 92%RH. Based on this first protective film, moisture can be appropriately imparted to the laminate (preferably a polarizing element) during, for example, the humidification treatment described below. On the other hand, the first protective film has a moisture permeability of, for example, 5 g / m²·24 h or more at 40°C and 92%RH.

[0049] As described above, the first protective film 31 can be adhered to the polarizing plate 10 via an adhesive layer. The adhesive layer can have any suitable composition. Specific examples include acrylic adhesives, rubber adhesives, silicone adhesives, polyester adhesives, carbamate adhesives, epoxy adhesives, and polyether adhesives. By adjusting the type, quantity, combination, and mixing ratio of monomers in the base resin forming the adhesive, as well as the amount of crosslinking agent, reaction temperature, and reaction time, an adhesive with desired target properties can be prepared. The base resin of the adhesive can be used alone or in combination of two or more. The base resin is preferably an acrylic resin (specifically, the adhesive layer is preferably composed of an acrylic adhesive). The thickness of the adhesive layer is, for example, 5 μm to 15 μm. The storage modulus of the adhesive layer at 25°C is, for example, 1.0 × 10⁵ Pa to 1.0 × 10⁷ Pa.

[0050] In one embodiment, a laminate (hereinafter referred to as "surface protective film") on which the aforementioned adhesive layer is pre-formed on the first protective film is used. The thickness of the surface protective film is preferably 20 μm to 100 μm, more preferably 30 μm to 90 μm. Furthermore, as described above, when the first protective film is peeled off, the adhesive layer (the entire surface protective film) can be peeled off together.

[0051] A-5. Second protective film The second protective film 32 can be made of any suitable plastic film. Specific examples of plastic films include polyethylene terephthalate (PET) film, polyethylene film, and polypropylene film. As described above, the second protective film 32 can function as a release liner. Specifically, the second protective film 32 is preferably a plastic film with a surface coated with a release agent. Specific examples of release agents include silicone-based release agents, fluorinated release agents, and long-chain alkyl acrylate release agents.

[0052] 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 even more 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.

[0053] The second protective film preferably has a moisture permeability of 30 g / m²·24 h or less, and more preferably 20 g / m²·24 h or less, at 40°C and 92%RH. With this second protective film, for example, moisture can be appropriately imparted to the laminate (preferably a polarizing element) during the humidification process described below. On the other hand, the second protective film has a moisture permeability of, for example, 5 g / m²·24 h or more at 40°C and 92%RH.

[0054] A-6. Fabrication of Laminated Body The laminate 100 can be obtained, for example, by laminating a polarizing plate 10 and a phase difference layer 20 to create a laminate precursor, and then laminating a first protective film 31 and a second protective film 32 onto the obtained laminate precursor.

[0055] The deposition of the polarizing plate 10 and the retardation layer 20 is performed, for example, by rolling them together (in a so-called roll-to-roll manner). Deposition can typically be performed by transferring a liquid crystal alignment and curing layer formed on a substrate. As shown in FIG2, when the retardation layer has a deposited structure, the retardation layers can be deposited (transferred) sequentially onto the polarizing plate, or a deposit of the retardation layers can be deposited (transferred) onto the polarizing plate.

[0056] The above transfer is performed, for example, using an active energy line curing adhesive. The thickness of the cured active energy line curing adhesive (the 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 to 1.5 μm. The above warping is caused, for example, by the adhesive used in the lamination of the polarizing plate and the retardation layer (specifically, the shrinkage of the active energy line curing adhesive during curing), and warping may occur in the laminate precursor obtained by laminating the polarizing plate 10 and the retardation layer 20.

[0057] Figure 3 is a cross-sectional view showing an example of the warping state of a laminate precursor. Furthermore, in Figure 3, the cross-section of the laminate precursor is omitted for ease of observation. In the example shown in Figure 3, a convex warping occurs on the side of the polarizer 10 in the laminate precursor 90. The warping tends to occur along the absorption axis of the polarizer 10 (polarizing element 11).

[0058] The deposition of the polarizing plate 10 and the retardation layer 20 is preferably carried out in an environment where the water vapor concentration (A1) is below 10.2 g / m³. More preferably, the water vapor concentration (A1) during deposition is between 6.0 g / m³ and 10.0 g / m³, and even more preferably between 8.0 g / m³ and 9.5 g / m³. By carrying out deposition in an environment with a water vapor concentration (A1) within this range, the effects obtained, for example, by the humidification treatment described below, become significant. This water vapor concentration (A1) during deposition can be achieved, for example, by varying the relative humidity with temperature within a range of 18°C ​​to 25°C. The water vapor content (A1) can be achieved, for example, at a temperature of 18°C ​​by setting the relative humidity to 65%RH or lower; at a temperature of 20°C by setting the relative humidity to 55%RH or lower; and at a temperature of 23°C by setting the relative humidity to 45%RH or lower. Furthermore, the lower limit of relative humidity can be, for example, 30%RH.

[0059] As described above, when the laminate further has other functional layers (e.g., conductive layers, other phase difference layers), the functional layers can be laminated or formed at specific locations by any appropriate method.

[0060] The lamination of the preform having the polarizing plate 10 and the retardation layer 20 with the first protective film 31 is performed, for example, by bonding the aforementioned surface protective film. The lamination of the preform having the second protective film 32 is performed, for example, using an adhesive. The thickness of the adhesive (the thickness of the adhesive layer disposed between the retardation layer 20 and the second protective film 32) is preferably 10 μm to 20 μm.

[0061] The aforementioned laminate can be humidified. By humidifying the laminate (preferably a polarizing element), moisture can be imparted to it, thereby correcting warpage that occurs after the polarizing plate and retardation layer are laminated. Furthermore, it is preferable that the laminate does not warp during the following storage process.

[0062] The humidification process described above is carried out, for example, by placing the laminate in an environment with a temperature of 18°C ​​to 34°C and a relative humidity of 60% to 90% RH. The water vapor content (A2) during the humidification process is preferably 10.5 g / m³ to 30 g / m³, and more preferably 11 g / m³ to 20 g / m³.

[0063] The water vapor content (A2) during the humidification process described above can be achieved, for example, at a temperature of 18°C ​​by setting the relative humidity to 80%RH or higher; at a temperature of 20°C by setting the relative humidity to 60%RH or higher; and at a temperature of 23°C by setting the relative humidity to 50%RH or higher. Furthermore, the upper limit of the relative humidity can be, for example, 100%RH.

[0064] In one embodiment, the laminate is humidified in an environment where the water vapor content is greater than the aforementioned water vapor content (A1). More specifically, the difference between the water vapor content (A2) and the aforementioned water vapor content (A1) during humidification is preferably 0.5 g / m³ or more, more preferably 1.0 g / m³ to 28 g / m³, even more preferably 1.0 g / m³ to 12 g / m³, particularly preferably 1.5 g / m³ to 10 g / m³, and most preferably 1.5 g / m³ to 8 g / m³. By humidifying under these conditions, an appropriate amount of moisture can be imparted to the laminate. More specifically, moisture can be imparted to the laminate without causing it to shrink. If too much moisture is imparted to the laminate during humidification, for example, initial warping and warping opposite to the direction of the convexity may occur, and / or warping in the plane may occur in a direction orthogonal to the direction of the initial warping.

[0065] The humidification treatment time is preferably 6 hours or more, more preferably 12 hours or more, and even better, 18 hours or more. On the other hand, the humidification treatment time is, for example, less than 48 hours.

[0066] A-7. Positional relationship between polarizing element and laminate In the laminate, the center of the polarizing element in the thickness direction is located within a range of less than 10% of half the thickness of the laminate from the center in the thickness direction. This positional relationship suppresses warping caused by temperature / humidity variations. As a result, a polarizing plate with a retardation layer whose warping is suppressed can be obtained. Preferably, the center of the polarizing element in the thickness direction is located within a range of less than 8% of half the thickness of the laminate from the center in the thickness direction, and more preferably within a range of less than 4% of half the thickness of the laminate from the center in the thickness direction.

[0067] Figure 4 illustrates the positional relationship between the center of the polarizing element and the center of the laminate. Furthermore, for ease of observation, shading is omitted in a portion of the laminate in Figure 4. The laminate 100 sequentially comprises: a surface protective film 50 containing a first protective film 31 and an adhesive layer 52; a polarizing plate 10 containing a protective layer 12 and a polarizing element 11; an adhesive layer 54; a first retardation layer 21; an adhesive layer 56; a second retardation layer 22; an adhesive layer 58; and a second protective film (isolating film) 32. 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 laminate 100 is set to less than 10% of half the thickness T of the laminate 100. In the example shown, in the thickness direction, the center 11a of the polarizing element 11 is located closer to the retardation layers 21 and 22 than the center 100a of the laminate 100, but it can also be located closer to the protective layer 12 than the center 100a of the laminate 100. In one embodiment, the position of the center of the polarizing element relative 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.

[0068] B. Manufacturing method of polarizing plate with phase retardation layer A method for manufacturing a polarizing plate with a retardation layer according to one embodiment of the present invention includes: preparing the aforementioned laminate; and storing (including transporting) the laminate. Specifically, the aforementioned laminate can be used as a polarizing plate with a retardation layer after storage. Based on the aforementioned laminate, warping during storage (specifically, due to changes in temperature / humidity) can be suppressed. As a result, warping of the obtained polarizing plate with a retardation layer is suppressed, for example, it can be well laminated onto an image display panel. [Example]

[0069] The present invention will now be specifically described by way of examples, but the present invention is not limited to these examples. Furthermore, the thickness and moisture permeability are values ​​measured by the methods described below. Also, unless otherwise specified, "parts" and "%" in the examples and comparative examples are based on weight. <Thickness> Thicknesses below 10 μm were measured using a scanning electron microscope (manufactured by Nippon Electronics Co., Ltd., product name "JSM-7100F"). Thicknesses exceeding 10 μm were measured using a digital micrometer (manufactured by Anritsu Co., Ltd., product name "KC-351C"). <Moisture permeability> The permeability is determined by the cup method (JIS Z 0208).

[0070] [Example 1] (Production of polarizing plates) A strip-shaped amorphous polyethylene terephthalate copolymer film (thickness: 100 μm) with a Tg of approximately 75°C and phthalic acid copolymer was used as the thermoplastic resin substrate, and one side of the resin substrate was subjected to corona treatment. To 100 parts by weight of a PVA-based resin prepared by mixing polyvinyl alcohol (degree of polymerization 4200, degree of saponification 99.2 mol%) and acetoacetyl-modified PVA (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name "GOHSEFIMER") in a 9:1 ratio, 13 parts by weight of potassium iodide were added. The resulting substance was dissolved in water to prepare a PVA aqueous solution (coating solution). The above-mentioned PVA aqueous solution is coated on the corona-treated surface of the resin substrate and dried at 60°C to form a PVA-based resin layer with a thickness of 13 μm, thereby obtaining a laminate. The obtained laminate was uniaxially stretched to 2.4 times its original length in an oven at 130°C (air-assisted stretching process). Then, the laminate is immersed in an insoluble bath (an aqueous solution of boric acid prepared by mixing 4 parts by weight of boric acid with 100 parts by weight of water) at a liquid temperature of 40°C for 30 seconds (insoluble treatment). Then, the polarizing element is immersed in a dyeing bath at 30°C (an iodine aqueous solution obtained by mixing iodine and potassium iodide in a weight ratio of 1:7 relative to 100 parts by weight of water) for 60 seconds while adjusting the concentration so that the final polarizing element's monomer transmittance (Ts) becomes the desired value (dyeing treatment). Then, immerse the sample in a crosslinking bath at a liquid temperature of 40°C (a boric acid aqueous solution obtained by mixing 3 parts by weight of potassium iodide and 5 parts by weight of boric acid with 100 parts by weight of water) for 30 seconds (crosslinking treatment). Then, the laminate is immersed in a boric acid aqueous solution (boric acid concentration 4 wt%, potassium iodide concentration 5 wt%) at a liquid temperature of 70°C, and is uniaxially stretched in the longitudinal direction (in-water stretching treatment) between rollers with different circumferential speeds at a total stretch ratio of 5.5. Subsequently, the laminate was immersed in a washing bath at a liquid temperature of 20°C (an aqueous solution of 4 parts by weight of potassium iodide mixed with 100 parts by weight of water) (washing treatment). Subsequently, it is dried in an oven at approximately 90°C while being in contact with SUS heated rollers at a surface temperature of approximately 75°C (drying shrinkage treatment). Thus, a polarizing element with a thickness of about 5 μm is formed on the resin substrate, resulting in a laminate with a resin substrate / polarizing element structure.

[0071] An HC-COP film (27 μm thick) was laminated as a protective layer onto the polarizing element side of the obtained laminate using an ultraviolet-curable adhesive. Furthermore, the HC-COP film is formed on a cyclic olefin resin (COP) film (25 μm thick) with an HC layer (2 μm thick), and was laminated with the COP film serving as the polarizing element side. Then, the resin substrate was peeled off from the polarizing element to obtain a polarizing plate having the HC-COP film (protective layer) / polarizing element configuration.

[0072] (Fabrication of the phase difference layer) A liquid crystal composition (coating solution) was prepared by dissolving 10 g of a polymerizable liquid crystal (manufactured by BASF Corporation; trade name "Paliocolor LC242", represented by the following formula) exhibiting a nematic liquid crystal phase and 3 g of a photopolymerization initiator for the polymerizable liquid crystal compound (manufactured by BASF Corporation; trade name "Irgacure 907") in 40 g of toluene. [Chemistry 1]

[0073] Alignment treatment was performed by rubbing the surface of a polyethylene terephthalate (PET) film (38 μm thick) with a rubbing cloth. The alignment treatment direction was set to 15° relative to the absorption axis of the polarizing element when viewed from the viewing side when bonded to the polarizing plate. The liquid crystal coating liquid described above was applied to the alignment-treated surface using a rod coater and dried at 90°C for 2 minutes to align the liquid crystal compound. The liquid crystal layer formed in this manner was then irradiated with light of 1 mJ / cm² using a metal halide lamp to harden the liquid crystal layer, thereby forming a liquid crystal alignment cured layer A (H layer) on the PET film. The thickness of the liquid crystal alignment cured layer A was 2.5 μm, and the in-plane phase difference Re(550) was 270 nm. Furthermore, the liquid crystal alignment cured layer A exhibited refractive index characteristics of nx > ny = nz.

[0074] The coating thickness was changed, and the alignment treatment direction was set to 75° relative to the absorption axis of the polarizing element when viewed from the viewing side. Otherwise, the same procedure was followed to form a liquid crystal alignment and curing layer B (Q layer) on the PET film. The thickness of the liquid crystal alignment and curing layer B was 1.5 μm, and the in-plane phase difference Re(550) was 140 nm. Furthermore, the liquid crystal alignment and curing layer B exhibited a refractive index characteristic of nx > ny = nz.

[0075] (Fabrication of laminated bodies) The obtained liquid crystal alignment and curing layer A (H layer) and liquid crystal alignment and curing layer B (Q layer) are sequentially transferred to the polarizing element side of the obtained polarizing plate. At this time, the transfer (bonding) is performed with the angle between the absorption axis of the polarizing element and the late phase axis of alignment and curing layer A being 15° and the angle between the absorption axis of the polarizing element and the late phase axis of alignment and curing layer B being 75°. The transfer of liquid crystal alignment and curing layer A (H layer) is performed using a UV-curable adhesive (0.5 μm thick). The transfer of liquid crystal alignment and curing layer B (Q layer) is performed using a UV-curable adhesive (1.5 μm thick). Thus, a laminate precursor is obtained. Furthermore, the transfer is performed while being conveyed by rollers. Furthermore, the transfer is performed in an environment with a water vapor concentration of 9.3 g / m³ (23°C and 45%RH). The total thickness of the obtained laminate precursor was 36 μm, with a thickness ratio of 8.

[0076] The obtained elongated laminate precursor was cut at a 45° angle relative to both the length and width directions (directions orthogonal to the length direction) to obtain a single-sheet laminate precursor measuring 165 mm × 80 mm. Furthermore, the length direction corresponds to the absorption axis direction of the polarizing element.

[0077] Then, a surface protective film (48 μm thick) is bonded to the protective layer side of the polarizing plate of the laminate precursor. Furthermore, the surface protective film is a film with an adhesive layer (10 μm thick) formed on the PET film (38 μm thick, moisture permeability 18 g / m2·24 h). Then, a PET film (50 μm thick, moisture permeability 13 g / m2·24 h) is bonded to the liquid crystal alignment curing layer B (Q layer) side of the laminate precursor via an adhesive layer (15 μm thick) to obtain a single sheet laminate of 165 mm × 80 mm.

[0078] (Humidification treatment) The obtained monolayer was placed in an environment of 23°C and 60%RH (water vapor content of 12.4 g / m3) for 24 hours to correct the warping generated in the above-mentioned laminate precursor.

[0079] [Example 2] In the fabrication of the laminate, a 60 μm thick surface protective film (a film with an adhesive layer (10 μm thick) formed on the protective layer side of the polarizing plate of the laminate precursor) is laminated. Otherwise, the operation is the same as in Example 1 to obtain the laminate.

[0080] [Example 3] In the fabrication of the laminate, a 60 μm thick surface protective film (a film with an adhesive layer (10 μm thick) formed on a PET film (50 μm thick, 13 g / m2·24 h permeability)) is laminated to the protective layer side of the polarizing plate of the laminate precursor, and a release film (PET film, 75 μm thick, 10 g / m2·24 h permeability) is laminated to the liquid crystal alignment and curing layer B (Q layer) side of the laminate precursor via an adhesive layer (15 μm thick). Otherwise, the operation is the same as in Example 1 to obtain the laminate.

[0081] [Example 4] In the fabrication of the laminate, a surface protective film with a thickness of 85 μm (a film with an adhesive layer (thickness of 10 μm) formed on the protective layer side of the polarizing plate of the laminate precursor) is laminated, and a release film (PET film, thickness of 75 μm, moisture permeability of 10 g / m2·24 h) is laminated on the liquid crystal alignment and curing layer B (Q layer) side of the laminate precursor via an adhesive layer (thickness of 15 μm) is laminated. Otherwise, the operation is the same as in Example 1 to obtain the laminate.

[0082] [Comparative Example 1] In the fabrication of the laminate, a release film (PET film, 38 μm thick, moisture permeability 18 g / m2·24 h) is bonded to the liquid crystal alignment and curing layer B (Q layer) side of the laminate precursor via an adhesive layer (15 μm thick). Otherwise, the operation is the same as in Example 1 to obtain the laminate.

[0083] [Comparative Example 2] In the fabrication of the laminate, a release film (PET film, 75 μm thick, moisture permeability 10 g / m2·24 h) is bonded to the liquid crystal alignment and curing layer B (Q layer) side of the laminate precursor via an adhesive layer (15 μm thick). Otherwise, the operation is the same as in Example 1 to obtain the laminate.

[0084] [Comparative Example 3] In the fabrication of the laminate, a 60 μm thick surface protective film (a film with an adhesive layer (10 μm thick) formed on a PET film (50 μm thick, 13 g / m2·24 h permeability)) is laminated to the protective layer side of the polarizing plate of the laminate precursor, and a release film (PET film, 38 μm thick, 18 g / m2·24 h permeability) is laminated to the liquid crystal alignment and curing layer B (Q layer) side of the laminate precursor via an adhesive layer (15 μm thick). Otherwise, the operation is the same as in Example 1 to obtain the laminate.

[0085] [Comparative Example 4] In the fabrication of the laminate, a surface protective film with a thickness of 85 μm (a film with an adhesive layer (thickness of 10 μm) formed on the protective layer side of the polarizing plate of the laminate precursor) is laminated, and a release film (PET film, thickness of 38 μm, moisture permeability of 18 g / m2·24 h) is laminated on the liquid crystal alignment and curing layer B (Q layer) side of the laminate precursor via an adhesive layer (thickness of 15 μm). Otherwise, the operation is the same as in Example 1 to obtain the laminate.

[0086] [Comparative Example 5] In the fabrication of the laminate, a surface protective film with a thickness of 85 μm (a film with an adhesive layer (thickness of 10 μm) formed on the protective layer side of the polarizing plate of the laminate precursor) is laminated, and a release film (PET film, thickness of 50 μm, moisture permeability of 13 g / m2·24 h) is laminated on the liquid crystal alignment and curing layer B (Q layer) side of the laminate precursor via an adhesive layer (thickness of 15 μm) is laminated. Otherwise, the operation is the same as in Example 1 to obtain the laminate.

[0087] <Evaluation> The laminates of each embodiment and comparative example after humidification treatment were stored in an environment of 23°C and 55%RH for 48 hours, and the changes in warpage before and after storage were measured. Specifically, a 140 mm × 70 mm specimen is cut from the laminate. This cutting is done with the absorption axis of the polarizing element aligned with the long side. The height of the highest point from the plane is measured when the cut specimen is left to rest with its separator side aligned with the plane, and the warpage is calculated. Here, warpage protruding on the resting side is designated as "positive (+)", and warpage protruding on the opposite side is designated as "negative (-)". Then, the difference between the warpage of the laminate before and after storage is calculated. The evaluation results, along with the center position of the polarizing element, are summarized in Table 1. Furthermore, the center position (%) of the polarizing element in Table 1 was determined as follows: As shown in Figure 4, it was calculated using the distance d between the center of the polarizing element and the center of the laminate in the thickness direction, and the thickness T of the laminate, according to the formula: d ÷ (T / 2) × 100. Also, the warpage variation (mm) in Table 1 is the average of the three measured samples. [Table 1] Example Comparative example 1 2 3 4 1 2 3 4 5 Thickness of surface protective film (μm) 48 60 60 85 48 48 60 85 85 Thickness of the separator (μm) 50 50 75 75 38 75 38 38 50 Center position of polarizing element (%) 2.6 9.8 4.8 7.5 11.5 11.9 18.5 30.1 21.8 Changes in warping (mm) -1 +3 -2 +2 -5 -6 +6 +10 +7

[0088] As clearly shown in Table 1, the warpage variation is small in the embodiments. Specifically, the corrected state of warpage generated in the laminate precursor is well maintained. [Industrial Applicability]

[0089] The polarizing plate with a phase retardation layer according to one embodiment of the present invention can be used as a polarizing plate with a phase retardation layer in an image display device, and is particularly suitable for use in an image display device that is flexible, or bendable, foldable, or rollable. Typical examples of image display devices include: liquid crystal display devices, organic EL display devices, and inorganic EL display devices.

[0090] 10:Polarizing plate 11: Polarizing element 11a: Center of polarizing element 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 50: Surface protective film 52: Adhesive layer 54: Adhesive layer 56: Adhesive layer 58: Adhesive layer 90: Precursor to a laminate 100: Laminated body 100a: Center of the laminated body d: Distance between the center of the polarizing element and the center of the laminate T: Thickness of the laminate

Claims

1. A laminate comprising, in sequence: a first protective film, a polarizing plate including a polarizing element and a protective layer disposed on at least one side of the polarizing element, a retardation layer, and a second protective film, wherein the combined thickness of the polarizing plate and the retardation layer is 40 μm or less, the ratio of the thickness of the polarizing plate to the thickness of the retardation layer is 5 or more, the thickness of the second protective film is 50 μm or more, the center of the polarizing element in the thickness direction is located within a range of less than 10% of half the thickness of the laminate from the center of the laminate in the thickness direction, and the distance between the center of the polarizing element and the center of the laminate in the thickness direction is d (μm), and the thickness of the laminate is T (μm), wherein the value obtained by formula: d÷(T / 2)×100 is 10 or less.

2. The laminate as claimed in claim 1, wherein the polarizing plate is provided with a protective layer only on the side of the polarizing element where the phase difference layer is not disposed.

3. The laminate as claimed in claim 1 or 2, wherein the phase retardation layer is an alignment and curing layer of a liquid crystal compound.

4. The laminate as claimed in claim 1 or 2, wherein the thickness of the first protective film is 15 μm or more and 90 μm or less.

5. A method for manufacturing a polarizing plate with a phase retardation layer, comprising: Prepare a multilayer body as requested in any of items 1 to 4; And to store the aforementioned laminated body.

6. The manufacturing method as described in claim 5, comprising: The above-mentioned polarizing plate and the above-mentioned phase difference layer are laminated to obtain a laminate precursor.

7. The manufacturing method as described in claim 6, comprising: The aforementioned laminate precursor is cut into single sheets.

8. The manufacturing method as described in claim 5, comprising: The polarizing plate and the phase difference layer are laminated using an active energy line curing adhesive.

9. The manufacturing method of claim 8, wherein the thickness of the above-mentioned active energy line curing adhesive after curing is 0.4 μm or more.

10. The manufacturing method as described in claim 5, comprising: The above-mentioned laminated body was humidified before being stored.

Images