Polarizing plate with phase difference layer and organic electroluminescence display device using the same

Abstract

The present application provides a polarizing plate with a phase difference layer that can significantly suppress discoloration when applied to an organic EL display device. The polarizing plate with a phase difference layer of an embodiment of the present application has a polarizer and a barrier layer disposed on one side of the polarizer and containing a phase difference layer, the barrier layer having a transmission amount of ammonia gas of 70 g / m 2 • 24 h or less.

Description

TECHNICAL FIELD

[0001] The present application relates to a polarizing plate with a phase difference layer and an organic electroluminescence (EL) display device using the same. BACKGROUND

[0002] In recent years, with the popularization of thin display devices, a display device (organic EL display device) equipped with an organic EL panel has been proposed. The organic EL panel has a metal layer having high reflectivity, and thus is likely to cause problems such as reflection of external light and mirroring of a background. Therefore, it is known that these problems are prevented by providing a circularly polarizing plate on the visual side (for example, Patent Document 1 and Patent Document 2). However, the circularly polarizing plate provided in the organic EL display device has a problem of being likely to discolor.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT DOCUMENTS

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2002-372622

[0006] Patent Document 2: Japanese Patent No. 3325560 SUMMARY

[0007] PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] The present application has been made to solve the above-described conventional problems, and has a main object to provide a polarizing plate with a phase difference layer that can significantly suppress discoloration when applied to an organic EL display device.

[0009] MEANS FOR SOLVING THE PROBLEMS

[0010] According to an embodiment of the present application, a polarizing plate with a phase difference layer is provided. The polarizing plate with a phase difference layer has a polarizer and a barrier layer disposed on one side of the polarizer and containing a phase difference layer, the barrier layer having an ammonia permeation amount of 70 g / m 2 or less per 24 hours.

[0011] In one embodiment, the phase difference layer has an ammonia permeation amount of 70 g / m 2 or less per 24 hours.

[0012] In one embodiment, the barrier layer contains a protective layer of the polarizer.

[0013] In one embodiment, the protective layer has an ammonia permeation amount of 70 g / m 2 or less per 24 hours.

[0014] In one embodiment, the polarizing plate with a phase difference layer has a protective layer disposed on the other side of the polarizer.

[0015] In one embodiment, the single transmittance of the polarizer described above is 40% or more and 45% or less.

[0016] In one embodiment, the Re(450) / Re(550) of the phase difference layer described above is 0.8 or more and less than 1.

[0017] In one embodiment, the thickness of the polarizer described above is 10 μm or less.

[0018] In one embodiment, the thickness of the polarizing plate with phase difference layer described above is 150 μm or less.

[0019] According to another aspect of the present application, there is provided an organic electroluminescent display device. The organic electroluminescent display device has the polarizing plate with phase difference layer described above.

[0020] Effects of Invention

[0021] According to the embodiments of the present application, in the polarizing plate with phase difference layer, by providing a layer satisfying a prescribed transmittance of ammonia gas on one side of the polarizer, it is possible to realize a polarizing plate with phase difference layer that can significantly suppress discoloration when applied to an organic EL display device. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a schematic cross-sectional view showing the outline configuration of the polarizing plate with phase difference layer of one embodiment of the present application.

[0023] Figure 2 is a schematic cross-sectional view showing the outline configuration of the polarizing plate with phase difference layer of one embodiment of the present application. DETAILED DESCRIPTION

[0024] Hereinafter, the embodiments of the present application will be described, but the present application is not limited to these embodiments.

[0025] (Definitions of Terms and Symbols)

[0026] The definitions of the terms and symbols in this specification are described below.

[0027] (1) Refractive Indexes (nx, ny, nz)

[0028] "nx" is the refractive index in the direction in which the refractive index in the plane becomes the largest (i.e., the slow axis direction), "ny" is the refractive index in the direction in the plane orthogonal to the slow axis (i.e., the fast axis direction), and "nz" is the refractive index in the thickness direction.

[0029] (2) In-Plane Phase Difference (Re)

[0030] "Re(λ)" is an in-plane retardation at 23°C measured by light of wavelength λ nm. For example, "Re(550)" is an in-plane retardation at 23°C measured by light of wavelength 550 nm. When the thickness of a layer (film) is set to d (nm), Re(λ) is calculated by the formula: Re(λ) = (nx-ny) x d.

[0031] (3) Thickness-direction phase difference (Rth)

[0032] "Rth(λ)" is a thickness-direction phase difference at 23°C measured by light of wavelength λ nm. For example, "Rth(550)" is a thickness-direction phase difference at 23°C measured by light of wavelength 550 nm. When the thickness of a layer (film) is set to d (nm), Rth(λ) is calculated by the formula: Rth(λ) = (nx-nz) x d.

[0033] (4) Nz coefficient

[0034] The Nz coefficient is calculated by Nz = Rth / Re.

[0035] (5) Angle

[0036] When an angle is mentioned in the present specification, the angle includes both clockwise and counterclockwise with respect to a reference direction. Thus, for example, "45°" means ±45°.

[0037] A. Polarizing plate with phase difference layer

[0038] Figure 1 is a schematic cross-sectional view showing the outline configuration of a polarizing plate with a phase difference layer according to an embodiment of the present application. The polarizing plate with a phase difference layer 100 has a polarizer 11, a protective layer (visual side protective layer) 12 disposed on the visual side of the polarizer 11, and a barrier layer 30 disposed on the side opposite the visual side of the polarizer 11. The barrier layer 30 includes, in order from the visual side, a protective layer (inner side protective layer) 13 of the polarizer 11 and a phase difference layer 20. As such, the protective layer 13 is disposed on the side opposite the visual side of the polarizer 11, but the protective layer 13 can be omitted depending on the purpose or the like. Specifically, the barrier layer 30 can not include the protective layer 13. For example, in the case where the phase difference layer 20 is composed of a stretched film of a resin film and can function as a protective layer of the polarizer, the protective layer 13 can be omitted. On the other hand, in the case where the phase difference layer 20 is an oriented cured layer of a liquid crystal compound, the protective layer 13 is typically disposed. The phase difference layer 20 can be a single layer or can have a laminated structure of two or more layers. Note that the laminate of the polarizer and the protective layer is referred to as a polarizing plate. In the illustrated example, the polarizing plate 10 has the polarizer 11 and the protective layers 12 and 13.

[0039] The thickness of the polarizing plate with a phase difference layer (the thickness from the visible side protective layer to the phase difference layer) is preferably 150 μm or less, more preferably 120 μm or less, further preferably 100 μm or less, and particularly preferably 80 μm or less. The lower limit of the thickness of the polarizing plate with a phase difference layer is preferably 20 μm, and more preferably 45 μm. Such a polarizing plate with a phase difference layer can have, for example, excellent flexibility and bending durability. As a result, the polarizing plate with a phase difference layer can be applied to an organic EL display device that can be bent, flexed, folded, rolled, or the like.

[0040] Although not shown, the polarizing plate with a phase difference layer can further have other functional layers. The kind, properties, number, combination, arrangement, and the like of the functional layers of the polarizing plate with a phase difference layer can be appropriately set according to the purpose. For example, the polarizing plate with a phase difference layer can further have a conductive layer or an isotropic substrate with a conductive layer. The polarizing plate with a phase difference layer having a conductive layer or an isotropic substrate with a conductive layer can be applied, for example, to an organic EL display device in which a touch sensor is incorporated inside an organic EL panel. As another example, the polarizing plate with a phase difference layer can further have another phase difference layer. The optical properties (e.g., refractive index properties, in-plane retardation, Nz coefficient, photoelastic coefficient), thickness, arrangement, and the like of the other phase difference layer can be appropriately set according to the purpose. As a specific example, another phase difference layer (typically, a layer imparting (elliptical) circularly polarizing function, a layer imparting ultra-high retardation) that improves visibility when viewed through polarized sunglasses can be provided on the visible side of the polarizing plate 10. By having such a layer, even when a display image is viewed through a polarizing lens such as polarized sunglasses, excellent visibility can be achieved. Thus, the resulting polarizing plate (polarizing plate with a phase difference layer) can be appropriately applied to an image display device that can be used outdoors.

[0041] Each member constituting the polarizing plate with a phase difference layer can be laminated via an arbitrary appropriate adhesive layer (not shown). As specific examples of the adhesive layer, an adhesive layer, a binder layer can be given. Specifically, the phase difference layer 20 can be attached to the polarizer 11 or the protective layer 13 via an adhesive layer (preferably, an active energy ray hardening type adhesive is used), or can be attached to the polarizer 11 or the protective layer 13 via a binder layer (e.g., an acrylic binder). In the case where the phase difference layer 20 has a laminated structure of two or more layers, each phase difference layer is attached, for example, via an adhesive layer (preferably, an active energy ray hardening type adhesive is used). The barrier layer 30 can also include an adhesive layer arranged between the polarizer 11 and the phase difference layer 20.

[0042] Although not shown, in practical applications, an adhesive layer is provided on the side of the phase difference layer 20 opposite the side on which the polarizer 11 is disposed (specifically, as the outermost layer on the side opposite the viewable side), and the polarizing plate with phase difference layer is made attachable to the organic EL panel main body. Furthermore, a release film (separator) is temporarily attached to the surface of the adhesive layer before the polarizing plate with phase difference layer is put into use. By temporarily attaching the release film, the adhesive layer can be protected, and a roll of the polarizing plate with phase difference layer can be formed.

[0043] The polarizing plate with phase difference layer can be in a long strip shape or in a single sheet shape. Here, the "long strip shape" refers to an elongated shape in which the length is sufficiently longer than the width, for example, an elongated shape in which the length is 10 times or more, preferably 20 times or more, the width. The polarizing plate with phase difference layer in a long strip shape can be wound into a roll shape.

[0044] A-1. Barrier Layer

[0045] The ammonia gas permeation amount of the barrier layer 30 is 70 g / m 2 • 60 g / m2or less, preferably 24 h 2 • 50 g / m2or less, more preferably 24 h 2 • 40 g / m2or less, further preferably 24 h 2 • 30 g / m2or less, particularly preferably 24 h 2 • 24 h. By providing such a barrier layer, discoloration can be significantly suppressed. The present inventors have faced the new problem of discoloration of the polarizing plate with phase difference layer when the polarizing plate with phase difference layer is applied to an organic EL display device, and have conducted intensive research on this problem, and as a result, have found that the cause of discoloration is ammonia (essentially ammonium ions) originating from the members that constitute the organic EL panel. By blocking the ammonia reaching the polarizer 11 as much as possible using such a barrier layer 30, discoloration can be significantly suppressed. Specifically, decomposition of the dichroic substance (typically, iodine complex) contained in the polarizer can be suppressed. The ammonia gas permeation amount of the barrier layer 30 is, for example, 3.0 g / m 2 • 24 h or more.

[0046] The ammonia gas permeation amount of the barrier layer 30 can be satisfied by at least one layer contained in the barrier layer 30, or can be satisfied by a combination of two or more layers contained in the barrier layer 30. Specifically, the ammonia gas permeation amount of the barrier layer 30 described above can be achieved by the protective layer 13 of the polarizer 11, can be achieved by the phase difference layer 20, can be achieved by the above-mentioned adhesive layer (for example, adhesive layer), or can be achieved by a combination of these. In one embodiment, the ammonia gas permeation amount of both the phase difference layer 20 and the protective layer 13, or either one, is 70 g / m 2 • 24 h or less.

[0047] The above-mentioned permeation amount of ammonia can be determined from the permeation amount of aqueous ammonia and the permeation amount of water, and the difference therebetween.

[0048] A-2. Polarizer

[0049] The above-mentioned polarizer is typically a film containing a dichroic substance (typically iodine).

[0050] For example, from the viewpoint of thinness, the thickness of the polarizer is preferably 15 μm or less, more preferably 12 μm or less, further preferably 10 μm or less, and particularly preferably 8 μm or less. On the other hand, the thickness of the polarizer is preferably 1 μm or more, more preferably 2 μm or more, and further preferably 3 μm or more. If the thickness of the polarizer is in such a range, for example, curling at the time of heating can be favorably suppressed, and good appearance durability at the time of heating can be obtained.

[0051] The polarizer preferably exhibits absorption dichroism at any wavelength in the range of 380 nm to 780 nm. The monomer transmittance of the polarizer is, for example, 40.0% or more, preferably 41.5% or more, more preferably 43.0% or more, and further preferably 44.5% or more. On the other hand, the monomer transmittance is, for example, 46.0% or less, and can be 45.0% or less. The polarizing degree of the polarizer is preferably 97.0% or more, more preferably 99.0% or more, and further preferably 99.9% or more.

[0052] The polarizer can be produced by any appropriate method. Specifically, the polarizer can be produced from a single-layered resin film, or can be produced using a laminate of two or more layers.

[0053] The method of producing the polarizer from the above-mentioned single-layered resin film typically includes dyeing treatment using a dichroic substance such as iodine or a dichroic dye, and stretching treatment. As the resin film, for example, a polyvinyl alcohol (PVA)-based film, a partially formacetylized PVA-based film, an ethylene-vinyl acetate copolymer-based partially saponified film, or the like is used. Preferably, from the viewpoint of excellent optical properties, the PVA-based film is dyed with iodine and uniaxially stretched to obtain the polarizer.

[0054] The above-mentioned dyeing with iodine is performed, for example, by immersing the PVA-based film in an aqueous iodine solution. The stretching ratio of the above-mentioned uniaxial stretching is preferably 3 to 7 times. The stretching can be performed after the dyeing, or can be performed while dyeing. Further, the dyeing can be performed after the stretching. The PVA-based film is subjected to swelling treatment, crosslinking treatment, washing treatment, drying treatment, or the like as needed. For example, by immersing the PVA-based film in water before the dyeing to perform water washing, not only dirt or an anti-blocking agent on the surface of the PVA-based film can be washed away, but also the PVA-based film can be swelled to prevent uneven dyeing, and the like.

[0055] As a specific example of the polarizer obtained using the above-described laminate, a polarizer obtained using a laminate of a resin substrate and a PVA-based resin layer (PVA-based resin film) laminated on the resin substrate, or a laminate of a resin substrate and a PVA-based resin layer formed by coating on the resin substrate can be given. The polarizer obtained using a laminate of a resin substrate and a PVA-based resin layer formed by coating on the resin substrate is, for example, produced by forming a PVA-based resin layer on a resin substrate by coating a PVA-based resin solution on the resin substrate and drying it, obtaining a laminate of a resin substrate and a PVA-based resin layer, and stretching and dyeing the laminate to make the PVA-based resin layer into a polarizer. In the present embodiment, it is preferable that a polyvinyl alcohol-based resin layer containing a halide and a polyvinyl alcohol-based resin be formed on one side of the resin substrate. Stretching typically includes immersing the laminate in an aqueous boric acid solution and stretching it. Further, the stretching can further include, as necessary, aerial stretching of the laminate at a high temperature (e.g., 95°C or higher) before stretching in the aqueous boric acid solution. Furthermore, in the present embodiment, it is preferable that the laminate be subjected to a drying shrinkage treatment by being heated while being conveyed in the longitudinal direction to shrink by 2% or more in the width direction. Typically, the production method of the present embodiment includes sequentially applying an aerial auxiliary stretching treatment, a dyeing treatment, an underwater stretching treatment, and a drying shrinkage treatment to the laminate. By introducing the auxiliary stretching, even in the case where PVA is coated on a thermoplastic resin, the crystallinity of the PVA can be improved, and high optical properties can be achieved. Furthermore, by simultaneously improving the orientation of the PVA in advance, the orientation of the PVA can be prevented from decreasing, dissolving, and the like when immersed in water in the subsequent dyeing step, stretching step, and the like, and high optical properties can be achieved. Further, in the case where the PVA-based resin layer is immersed in a liquid, compared to the case where the PVA-based resin layer does not contain a halide, the disorder of the orientation of the polyvinyl alcohol molecules and the decrease in the orientation can be suppressed. Thus, the optical properties of the polarizer obtained by the treatment steps in which the laminate is immersed in a liquid such as the dyeing treatment and the underwater stretching treatment can be improved. Further, by shrinking the laminate in the width direction using the drying shrinkage treatment, the optical properties can be improved. The obtained laminate of a resin substrate / polarizer can be used as it is (i.e., the resin substrate can be used as a protective layer for the polarizer), or can be used after the resin substrate is peeled from the laminate of a resin substrate / polarizer, on the peeled surface or the surface on the side opposite to the peeled surface, with a protective layer of any appropriate kind corresponding to the purpose being laminated. Details of such a production method of a polarizer are described, for example, in Japanese Patent Application Publication No. 2012-73580, Japanese Patent No. 6470455. The entire contents of these publications are incorporated herein by reference.

[0056] A-3. Protective layer

[0057] The protective layer described above is composed of any suitable film that can be used as a protective layer for a polarizer. As a material constituting the protective layer, for example, a cellulose-based resin such as triacetyl cellulose (TAC), a cyclic olefin-based resin such as poly norbornene, a (meth)acrylic resin, a polyester-based resin such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), a polyolefin-based resin such as polyethylene, and a polycarbonate-based resin can be exemplified. As a representative example of the (meth)acrylic resin, a (meth)acrylic resin having a lactone ring structure can be exemplified. The (meth)acrylic resin having a lactone ring structure is described, for example, in Japanese Patent Application Publication No. 2000-230016, Japanese Patent Application Publication No. 2001-151814, Japanese Patent Application Publication No. 2002-120326, Japanese Patent Application Publication No. 2002-254544, and Japanese Patent Application Publication No. 2005-146084. These publications are hereby incorporated by reference in their entirety into the present specification.

[0058] The polarizing plate with a phase difference layer is typically disposed on the viewable side of the organic EL display device, and for the protective layer 12 on the viewable side, surface treatment such as hard coat treatment, anti-reflection treatment, anti-sticking treatment, anti-glare treatment, and the like can be performed as necessary.

[0059] The thickness of the protective layer 12 on the viewable side can be appropriately set. The thickness of the protective layer 12 on the viewable side is preferably from 10 μm to 80 μm, more preferably from 15 μm to 70 μm, and further preferably from 20 μm to 50 μm. Note that in the case where surface treatment is performed, the thickness of the protective layer 12 on the viewable side is the thickness including the thickness of the surface treatment layer.

[0060] In one embodiment, the protective layer 13 has an ammonia permeation amount of 70 g / m 2 • 24 h or less, preferably 60 g / m 2 • 24 h or less, more preferably 50 g / m 2 • 24 h or less, further preferably 40 g / m 2 • 24 h or less, particularly preferably 30 g / m 2 • 24 h or less. In this case, as a material constituting the protective layer 13, at least one selected from the group consisting of a cellulose-based resin, a cyclic olefin-based resin, and a polyester-based resin is preferably used.

[0061] In one embodiment, the protective layer 13 is preferably optically isotropic. The term "optically isotropic" in the present specification 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. The thickness of the protective layer 13 can be appropriately set, for example, in accordance with the desired permeation amount of ammonia. The thickness of the protective layer 13 is preferably 10 μm to 80 μm, more preferably 20 μm to 70 μm, and further preferably 30 μm to 50 μm. In the case where the retardation layer 20 is a stretched film of a resin film, the protective layer 13 can be omitted, for example, from the viewpoint of thinness.

[0062] A-4. Retardation Layer

[0063] The retardation layer 20 can be a single layer or can have a stacked structure (essentially a two-layer structure).

[0064] In the case where the retardation layer 20 is a single layer, the retardation layer 20 typically functions as a λ / 4 plate. The retardation layer is typically provided in order to impart antireflection properties to the organic EL display device. The retardation layer typically exhibits a refractive index characteristic showing the relationship nx>ny=nz. The in-plane retardation Re(550) of the retardation layer is preferably 100 nm to 190 nm, more preferably 110 nm to 170 nm, and further preferably 120 nm to 160 nm. Note that "ny=nz" here includes not only the case where ny and nz are exactly equal but also the case where they are substantially equal. Thus, ny>nz or ny<nz can sometimes occur within a range that does not impair the effects of the present application.

[0065] The Nz coefficient of the retardation layer is preferably 0.9 to 1.5, and more preferably 0.9 to 1.3. By satisfying such a relationship, an organic EL display device having a very excellent reflected color tone can be obtained.

[0066] In the case where the retardation layer is a single layer, the retardation layer preferably exhibits a reverse dispersion wavelength characteristic in which the phase difference value increases in accordance with the wavelength of the measuring light. In this case, the Re(450) / Re(550) of the retardation layer is preferably 0.8 or higher and lower than 1, and more preferably 0.8 or higher and 0.95 or lower. If the configuration is such, a very excellent antireflection property can be achieved.

[0067] The angle formed by the slow axis of the retardation layer and the absorption axis of the polarizer is preferably 40° to 50°, more preferably 42° to 48°, and further preferably about 45°. If the angle is in such a range, by making the retardation layer a λ / 4 plate as described above, an organic EL display device having a very excellent antireflection property can be obtained.

[0068] The phase difference layer can be formed of any suitable material as long as it satisfies the above-described characteristics. Specifically, the phase difference layer can be a stretched film of a resin film or an oriented and cured layer of a liquid crystal compound (hereinafter, liquid crystal oriented and cured layer).

[0069] In the case where the phase difference layer is a stretched film of a resin film, as a representative example of the resin constituting the resin film, a polycarbonate-based resin or a polyester carbonate-based resin (hereinafter, sometimes simply referred to as a polycarbonate-based resin) can be listed. As the polycarbonate-based resin, any suitable polycarbonate-based resin can be used as long as it provides a desired moisture permeability. For example, the polycarbonate-based resin contains a structural unit derived from a fluorene-based dihydroxy compound, a structural unit derived from an isosorbide-based dihydroxy compound, and a structural unit derived from at least one dihydroxy compound selected from the group consisting of alicyclic glycol, alicyclic dimethanol, diethylene glycol, triethylene glycol, or polyethylene glycol, and an alkylene glycol or a spiro glycol. It is preferable that the polycarbonate-based resin contain a structural unit derived from a fluorene-based dihydroxy compound, a structural unit derived from an isosorbide-based dihydroxy compound, a structural unit derived from alicyclic dimethanol, and / or a structural unit derived from diethylene glycol, triethylene glycol, or polyethylene glycol; it is further preferable that the polycarbonate-based resin contain a structural unit derived from a fluorene-based dihydroxy compound, a structural unit derived from an isosorbide-based dihydroxy compound, and a structural unit derived from diethylene glycol, triethylene glycol, or polyethylene glycol. The polycarbonate-based resin can contain a structural unit derived from another dihydroxy compound as needed. The phase difference layer can be formed by stretching a film composed of the above-described polycarbonate-based resin under any suitable stretching conditions. Note that the details of the polycarbonate-based resin and the method of forming the phase difference layer are described, for example, in Japanese Patent Application Publication No. 2014-10291, Japanese Patent Application Publication No. 2014-26266, Japanese Patent Application Publication No. 2015-212816, Japanese Patent Application Publication No. 2015-212817, Japanese Patent Application Publication No. 2015-212818, Japanese Patent Application Publication No. 2017-54093, Japanese Patent Application Publication No. 2018-60014. The descriptions in these publications are incorporated herein by reference.

[0070] In the case where the phase difference layer is a liquid crystal alignment cured layer, by using a liquid crystal compound, the difference between nxand nyof the obtained phase difference layer can be made larger than that of a non-liquid crystal material, and thus the thickness of the phase difference layer for obtaining a desired in-plane phase difference can be made smaller. As a result, further thinning of the polarizing plate with the phase difference layer (as a result, the organic EL display device) can be achieved. The "alignment cured layer" in the present specification is a layer in which a liquid crystal compound is aligned in a prescribed direction within the layer and the alignment state thereof is fixed. Note that the "alignment cured layer" is a concept including an alignment hardened layer obtained by hardening a liquid crystal monomer. In the present embodiment, the liquid crystal compound, which is typically rod-shaped, is aligned in a state of being aligned in the slow axis direction of the phase difference layer (parallel alignment). Specific examples of the liquid crystal compound and details of the formation method of the liquid crystal alignment cured layer are described in, for example, Japanese Patent Application Laid-Open No. 2006-163343 and Japanese Patent Application Laid-Open No. 2006-178389. The descriptions of these publications are incorporated herein by reference in its entirety.

[0071] The thickness of the phase difference layer can be typically set to a thickness at which the function as a λ / 4 plate can be suitably performed. In the case where the phase difference layer is a stretched film of a resin film, the thickness of the phase difference layer can be, for example, 10 μm to 60 μm. In the case where the phase difference layer is a liquid crystal alignment cured layer, the thickness of the phase difference layer can be, for example, 1 μm to 5 μm.

[0072] In the case where the phase difference layer 20 has a layered structure, the phase difference layer typically has a two-layer structure of a first liquid crystal alignment cured layer and a second liquid crystal alignment cured layer. In this case, either one of the first liquid crystal alignment cured layer or the second liquid crystal alignment cured layer can function as a λ / 2 plate, and the other can function as a λ / 4 plate. Here, a case where the first liquid crystal alignment cured layer functions as a λ / 2 plate and the second liquid crystal alignment cured layer functions as a λ / 4 plate will be described, but they can also be reversed. The thickness of the first liquid crystal alignment cured layer can be adjusted in a manner to obtain a desired in-plane phase difference of a λ / 2 plate, and can be, for example, 2.0 μm to 4.0 μm. The thickness of the second liquid crystal alignment cured layer can be adjusted in a manner to obtain a desired in-plane phase difference of a λ / 4 plate, and can be, for example, 1.0 μm to 2.5 μm. The in-plane phase difference Re(550) of the first liquid crystal alignment cured layer is preferably 200 nm to 300 nm, more preferably 230 nm to 290 nm, and further preferably 250 nm to 280 nm. The in-plane phase difference Re(550) of the second liquid crystal alignment cured layer is preferably 100 nm to 190 nm, more preferably 110 nm to 170 nm, and further preferably 120 nm to 160 nm, as described above. The angle formed by the slow axis of the first liquid crystal alignment cured layer and the absorption axis of the polarizer is preferably 10° to 20°, more preferably 12° to 18°, and further preferably about 15°. The angle formed by the slow axis of the second liquid crystal alignment cured layer and the absorption axis of the polarizer is preferably 70° to 80°, more preferably 72° to 78°, and further preferably about 75°. If such a configuration is employed, a characteristic close to an ideal inverse wavelength dispersion characteristic can be obtained, and as a result, a very excellent antireflection characteristic can be achieved.

[0073] In one embodiment, the phase difference layer 20 has a transmittance of 70 g / m 2 • 60 g / m 2 • 50 g / m 2 • 40 g / m 2 • 30 g / m 2 • 24 h or less. In this case, as the phase difference layer 20, a stretched film of the above-described resin film is preferably used. As the constituent material of the protective layer 13 combined with the stretched film of the resin film, i.e., the phase difference layer 20, at least one selected from the group consisting of a cyclic olefin-based resin and a polyester-based resin is preferably used. According to such a combination, discoloration can be remarkably suppressed.

[0074] As the constituent material of the protective layer 13 combined with the liquid crystal alignment cured layer, i.e., the phase difference layer 20, a cellulose-based resin is preferably used. According to such a combination, discoloration can be remarkably suppressed.

[0075] B. Organic EL display device

[0076] The polarizing plate with a phase difference layer described above can be applied to an organic EL display device. Therefore, the organic EL display device of the embodiment of the present application has the polarizing plate with a phase difference layer described above.

[0077] Figure 2 is a schematic cross-sectional view showing a state in which the polarizing plate with a phase difference layer is arranged on the organic EL panel in the organic EL display device of the embodiment of the present application. The polarizing plate with a phase difference layer 100 is arranged in a manner that the blocking layer 30 thereof becomes the organic EL panel main body 40 side as compared with the polarizer 11. Specifically, the polarizing plate with a phase difference layer 100 is attached on the organic EL panel main body 40 via an adhesive layer (not shown). The organic EL panel main body 40 has a substrate 60, and an upper structure layer 80 including a circuit layer containing a thin film transistor (TFT) or the like, an organic light emitting diode (OLED), a sealing film sealing the OLED, and the like. In the upper structure layer 80, for example, a nitrogen-containing layer (for example, a nitride layer) is included, and ammonia (ammonium ion) can be generated from the upper structure layer 80. According to the polarizing plate with a phase difference layer described above, discoloration can be significantly suppressed in the organic EL display device. Furthermore, the problem of discoloration can be solved without designing a change in the configuration of the organic EL panel main body.

[0078] For example, in the case where a flexible substrate (for example, a resin substrate) is used as the substrate 60, the resulting organic EL display device can be implemented to be bent, curved, folded, rolled, or the like.

[0079] Example

[0080] Hereinafter, the present application will be specifically described by way of examples, but the present application is not limited by these examples. The measuring method of each property is described below. Note that, unless otherwise specifically noted, "parts" and "%" in the examples and comparative examples are on a weight basis.

[0081] (1) Thickness

[0082] The thickness of 10 μm or less was measured using an interference film thickness meter (Otsuka Electronics Co., Ltd., product name "MCPD-3000"). The thickness exceeding 10 μm was measured using a digital micrometer (ANRITSU Corporation, product name "KC-351C").

[0083] (2) Ammonia gas permeation amount

[0084] Two cups A and B were prepared, 150 g of 10% ammonia aqueous solution was added to cup A, and 150 g of water was added to cup B. A test piece (film) cut in a circle having a diameter of 6 cm was sealed, and the cups A and B were left to stand in an oven set at 40°C (under atmospheric pressure) for 24 hours in this state. The weight change of the cups A and B before and after the standing was measured. The difference between the weight change of cup A (amount of permeation of ammonia and water) and the weight change of cup B (amount of permeation of water) was calculated, and the amount of permeation of ammonia (g / m 2 24h) was obtained.

[0085] [Example 1]

[0086] 1. Production of polarizer

[0087] As the thermoplastic resin substrate, an amorphous copolymerized polyethylene terephthalate film of isophthalic acid (lengthy, water absorption 0.75%, Tg about 75°C) having a thickness of 100 μm was used. Corona treatment was performed on one side of the resin substrate.

[0088] 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 acetyl acetyl-modified PVA (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name "GOHSEFIMER Z410") at a ratio of 9:1, 13 parts by weight of potassium iodide was added, and the resulting substance was dissolved in water to prepare a PVA aqueous solution (coating solution).

[0089] A PVA-based resin layer having a thickness of 13 μm was formed by applying the above PVA aqueous solution to the corona-treated surface of the resin substrate and drying at 60°C, and a laminate was produced.

[0090] The resulting laminate was subjected to free-end uniaxial stretching to 2.4 times in the longitudinal direction (lengthwise direction) at different circumferential speeds between rollers in an oven at 130°C (overhead assisted stretching treatment).

[0091] Next, the laminate was immersed in an insolubilization bath (boric acid aqueous solution obtained by adding 4 parts by weight of boric acid to 100 parts by weight of water) at a liquid temperature of 40°C for 30 seconds (insolubilization treatment).

[0092] Next, the laminate was immersed in a dyeing bath (iodine aqueous solution obtained by adding iodine and potassium iodide at a weight ratio of 1:7 to 100 parts by weight of water) at a liquid temperature of 30°C for 60 seconds while adjusting the concentration so that the monomer transmittance (Ts) of the finally obtained polarizing film becomes 43.0% (dyeing treatment).

[0093] Next, the laminate was immersed in a crosslinking bath (boric acid aqueous solution obtained by adding 3 parts by weight of potassium iodide and 5 parts by weight of boric acid to 100 parts by weight of water) at a liquid temperature of 40°C for 30 seconds (crosslinking treatment).

[0094] After that, the laminate was uniaxially stretched (water stretching treatment) in the longitudinal direction (lengthwise direction) at a total stretching ratio of 5.5 times while being immersed in an aqueous boric acid solution (boric acid concentration 4.0% by weight, potassium iodide 5.0% by weight) at a liquid temperature of 70°C while being passed between rollers having different circumferential speeds.

[0095] After that, the laminate was immersed in a washing bath (aqueous solution obtained by mixing 4 parts by weight of potassium iodide with respect to 100 parts by weight of water) at a liquid temperature of 20°C (washing treatment).

[0096] After that, while being dried in an oven maintained at 90°C, the laminate was contacted with a heating roller made of SUS having a surface temperature maintained at 75°C for about 2 seconds (drying shrinkage treatment). The shrinkage ratio in the width direction of the laminate subjected to the drying shrinkage treatment was 5.2%.

[0097] By such an operation, a polarizer having a thickness of 5 μm was formed on the resin substrate.

[0098] 2. Production of Polarizing Plate

[0099] The polarizer surface of the laminate of the resin substrate / polarizer obtained in the above was bonded with a TAC film having a thickness of 25 μm via an ultraviolet hardening type adhesive. Specifically, coating was performed in such a manner that the thickness of the hardening type adhesive became 1.0 μm, and bonding was performed using a roll machine. After that, the adhesive was hardened by irradiating UV light from the TAC film side. Next, the resin substrate was peeled from the polarizer, and the peeling surface was bonded with a cyclic olefin resin film (thickness 13 μm, ammonia permeation amount 54 g / m 2 24 h: the following, COP film). By such an operation, a polarizing plate having a constitution of TAC film / polarizer / COP film was obtained.

[0100] 3. Production of Phase Difference Film Constituting Phase Difference Layer

[0101] 3-1. Polymerization of Polycarbonic Resin

[0102] Polymerization was performed using a batch polymerization device including two vertical reactors equipped with stirring wings and reflux coolers controlled to 100°C. Bis[9-(2-phenoxy carbonyl ethyl) fluorene-9-yl]methane 29.60 parts by mass (0.046 mol), isosorbide (ISB) 29.21 parts by mass (0.200 mol), spirodiol (SPG) 42.28 parts by mass (0.139 mol), diphenyl carbonate (DPC) 63.77 parts by mass (0.298 mol), and calcium acetate monohydrate 1.19 x 10 -2 parts by mass (6.78 x 10 -5mol). After the inside of the reactor was replaced with nitrogen under reduced pressure, the reactor was warmed with a heating medium, and stirring was started when the inside temperature reached 100°C. Forty minutes after the start of the temperature increase, the inside temperature reached 220°C, and the temperature was controlled so as to maintain this temperature while reducing the pressure. After the temperature reached 220°C, the pressure was set to 13.3 kPa over 90 minutes. The phenol vapor produced as a byproduct of the polymerization was introduced into a reflux cooler at 100°C, and some of the monomer components contained in the phenol vapor were returned to the reactor. The uncondensed phenol vapor was introduced into a condenser at 45°C and was recovered. After the inside of the first reactor was temporarily returned to atmospheric pressure by introducing nitrogen, the oligomerized reaction solution in the first reactor was transferred to the second reactor. Subsequently, the temperature in the second reactor was increased and the pressure was reduced, and the temperature was set to 240°C and the pressure was set to 0.2 kPa over 50 minutes. Thereafter, the polymerization was performed until the prescribed stirring power was reached. At the time when the prescribed power was reached, the pressure was returned to atmospheric pressure by introducing nitrogen into the reactor, and the resulting polyester carbonate resin was extruded into water, and the strands were cut to obtain pellets.

[0103] 3-2. Production of phase difference film

[0104] After the resulting polyester carbonate resin (pellets) were vacuum-dried at 80°C for 5 hours, a film was produced using a film production apparatus equipped with a single-screw extruder (Toshiba Machine Co., Ltd., cylinder set temperature: 250°C), a T die (width: 200 mm, set temperature: 250°C), a chill roll (set temperature: 120 to 130°C), and a winder. The resulting long resin film was stretched in the width direction at a stretching temperature of 133°C and a stretching ratio of 2.8 times to obtain a phase difference film having a thickness of 47 μm. The Re(550) of the resulting phase difference film was 141 nm, the Re(450) / Re(550) was 0.82, and the Nz coefficient was 1.12. In addition, the ammonia permeation amount of the resulting phase difference film was 10 g / m 2 for 24 hours.

[0105] 4. Preparation of adhesive

[0106] 4-1. Preparation of acrylic polymer

[0107] Into a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen introduction tube, and a cooler, a monomer mixture containing 91 parts of butyl acrylate, 6 parts of acryloyl morpholine (ACMO), 2.7 parts of acrylic acid, and 0.3 parts of 4-hydroxybutyl acrylate was put. Further, 0.1 part of 2,2'-azobisisobutyronitrile as a polymerization initiator was put together with 100 parts of ethyl acetate with respect to 100 parts of the monomer mixture, and after nitrogen replacement was performed while slowly stirring and introducing nitrogen, a polymerization reaction was performed for 8 hours while keeping the liquid temperature in the flask at around 55°C to prepare an acrylic polymer solution.

[0108] 4-2. Preparation of the adhesive

[0109] To 100 parts of the obtained acrylic polymer solution in terms of solid content, 0.1 parts of trimethylolpropane / tolylene diisocyanate adduct (manufactured by DKS Co., Ltd., trade name "Coronate L"), 0.3 parts of peroxide crosslinking agent (benzoyl peroxide), and 0.2 parts of epoxy group-containing silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "KBM-403") were added to obtain an adhesive. The ammonia permeation amount of the obtained adhesive (thickness 20 μm) was 118 g / m 2 ·24 h.

[0110] 5. Production of polarizing plate with retardation layer

[0111] The COP film surface of the polarizing plate obtained in the above 2. was attached to the retardation film obtained in the above 3. via the adhesive (thickness 20 μm) obtained in the above 4.. At this time, the attachment was performed in such a manner that the absorption axis of the polarizer and the slow axis of the retardation film form an angle of 45°. In this way, a polarizing plate with retardation layer was obtained.

[0112] [Example 2]

[0113] In the production of the polarizing plate, a PET film (thickness 30 μm, ammonia permeation amount 53 g / m 2 ·24 h) was used instead of the COP film, and otherwise the same operation as in Example 1 was performed to obtain a polarizing plate with retardation layer.

[0114] [Example 3]

[0115] In the production of the polarizing plate, a TAC film (thickness 25 μm, ammonia permeation amount 30 g / m 2 ·24 h) was used instead of the COP film, and otherwise the same operation as in Example 1 was performed to obtain a polarizing plate with retardation layer.

[0116] [Example 4]

[0117] In the production of the polarizing plate, an acrylic film having a lactone ring structure (thickness 20 μm, ammonia permeation amount 78 g / m 2 ·24 h) was used instead of the COP film, and otherwise the same operation as in Example 1 was performed to obtain a polarizing plate with retardation layer.

[0118] [Example 5]

[0119] In the production of the polarizing plate, the COP film was attached to the polarizer without using the ultraviolet-hardening adhesive, and otherwise the same operation as in Example 1 was performed to obtain a polarizing plate with retardation layer.

[0120] [Example 6]

[0121] As the phase difference layer, a liquid crystal alignment cured layer described below was used, and otherwise, the same operation as in Example 1 was performed to obtain a polarizing plate with a phase difference layer.

[0122] (Production of liquid crystal alignment cured layer constituting phase difference layer)

[0123] After 55 parts of a compound represented by Formula (I), 25 parts of a compound represented by Formula (II), and 20 parts of a compound represented by Formula (III) were added to cyclopentanone (CPN) 400 parts, it was dissolved by warming to 60°C and stirring, and after confirming dissolution, it was returned to room temperature, 3 parts of Irgacure 907 (manufactured by BASF Japan Ltd.), 0.2 parts of MEGAFAC F-554 (manufactured by DIC Corporation), and 0.1 parts of p-methoxyphenol (MEHQ) were added, and further stirring was performed to obtain a solution. The solution was transparent and uniform. The obtained solution was filtered with a 0.20-μm membrane filter to obtain a polymerizable composition. On the other hand, an alignment film was formed on a glass substrate having a thickness of 0.7 mm by coating a polyimide solution using a spin coating method, drying at 100°C for 10 minutes, and baking at 200°C for 60 minutes to obtain a coating film. The obtained coating film was subjected to rubbing treatment to form an alignment film. The rubbing treatment was performed using a commercially available rubbing device. The polymerizable composition obtained in the above was coated on the substrate (essentially the alignment film) by a spin coating method, and dried at 100°C for 2 minutes. After the obtained coated film was cooled to room temperature, it was irradiated with ultraviolet rays for 30 seconds at an intensity of 30 mW / cm 2 The in-plane retardation Re(550) of the obtained liquid crystal alignment cured layer was 130 nm, Re(450) / Re(550) was 0.851, and the liquid crystal alignment cured layer showed reverse dispersion wavelength characteristics. In addition, the ammonia permeation amount of the obtained liquid crystal alignment cured layer was 103 g / m 2 ·24h.

[0124] [Chemical Formula 1]

[0125]

[0126] [Chemical Formula 2]

[0127]

[0128] [Example 7]

[0129] In the production of the polarizing plate, a TAC film (thickness 25 μm, ammonia permeation amount 30 g / m 2• 24h) instead of the COP film; and, as the phase difference layer, the liquid crystal alignment cured layer was used, and otherwise, the same operation as in Example 1 was performed to obtain a polarizing plate with a phase difference layer.

[0130] [Comparative Example 1]

[0131] In the production of the polarizing plate, a TAC film having a thickness of 40 μm was used instead of the TAC film having a thickness of 25 μm, and an acrylic film having a lactone ring structure (thickness 20 μm, ammonia permeation amount 78 g / m 2 • 24h) instead of the COP film; and, as the phase difference layer, the liquid crystal alignment cured layer was used, and otherwise, the same operation as in Example 1 was performed to obtain a polarizing plate with a phase difference layer.

[0132] [Comparative Example 2]

[0133] In the production of the polarizing plate, a TAC film having a thickness of 40 μm was used instead of the TAC film having a thickness of 25 μm; and, as the phase difference layer, the liquid crystal alignment cured layer was used, and otherwise, the same operation as in Example 5 was performed to obtain a polarizing plate with a phase difference layer.

[0134] [Comparative Example 3]

[0135] In the production of the polarizing plate, an acrylic film having a lactone ring structure (thickness 20 μm) was used instead of the TAC film having a thickness of 25 μm, and an acrylic film having a lactone ring structure (thickness 20 μm, ammonia permeation amount 78 g / m 2 • 24h) instead of the COP film; and, as the phase difference layer, the liquid crystal alignment cured layer was used, and otherwise, the same operation as in Example 1 was performed to obtain a polarizing plate with a phase difference layer.

[0136] The following evaluations were performed for the Examples and Comparative Examples. The evaluation results are summarized in Table 1 together with the constitution of the polarizing plate with a phase difference layer (barrier layer).

[0137] <Evaluation>

[0138] 〇Monomer transmittance and degree of polarization

[0139] For the polarizing plate of the Examples and Comparative Examples, the monomer transmittance Ts, parallel transmittance Tp, and orthogonal transmittance Tc measured using a UV-visible spectrophotometer ("LPF-2000" manufactured by Otsuka Electronics Co., Ltd.) were respectively set as Ts, Tp, and Tc of a polarizer. These Ts, Tp, and Tc are Y values measured by a 2-degree field of view (C light source) of JIS Z 8701 and subjected to visibility correction. From the obtained Tp and Tc, the degree of polarization P was calculated by the following equation.

[0140] Polarization degree P (%) = {(Tp - Tc) / (Tp + Tc)} 1 / 2 x 100

[0141] Ammonia discoloration test

[0142] In a glass bottle (cylindrical shape with a diameter of 30 mm and a depth of 50 mm), 10 g of a 10% ammonia aqueous solution was added, and the opening of the glass bottle was covered with the polarizing plate with a retardation layer obtained in the examples and comparative examples (the retardation layer was in contact with the opening) and was sealed. In this state, the glass bottle was heated at 65°C for 2 hours. After the heating, the polarization degree of the portion corresponding to the opening of the glass bottle was measured, and the polarization degree of the polarizing plate with a retardation layer (essentially a polarizer) before the heating was set as P, and the polarization degree after the heating was set as P'. ΔP was calculated from the following formula. The smaller ΔP is, the more the discoloration caused by ammonia is suppressed.

[0143] ΔP = P - P'

[0144] [Table 1]

[0145]

[0146] In the examples, the polarizing plate with a retardation layer was obtained, in which ΔP was lower than 20%, and the polarization degree did not substantially change (no discoloration) even when exposed to ammonia. On the other hand, in the comparative examples, it was confirmed that the polarization degree was greatly reduced, and the polarizing function substantially disappeared.

[0147] Industrial applicability

[0148] The polarizing plate with a retardation layer of the present application is suitably used, for example, as a circular polarizing plate for anti-reflection for an organic EL display device.

[0149] Explanation of symbols

[0150] 10 Polarizing plate

[0151] 11 Polarizer

[0152] 12 Protective layer (protective layer on the visible side)

[0153] 13 Protective layer (protective layer on the inner side)

[0154] 20 Retardation layer

[0155] 30 Barrier layer

[0156] 100 Polarizing plate with a retardation layer

Claims

1. A polarizing plate with a phase difference layer, comprising: a polarizer; and a barrier layer disposed on one side of the polarizer and comprising a protective layer and a phase difference layer of the polarizer; the protective layer is composed of at least one selected from the group consisting of a cyclic olefin resin and a polyester resin, the phase difference layer is composed of a polycarbonate resin, 4. The polarizing plate with a phase difference layer according to any one of claims 1 to 3, comprising a protective layer disposed on the other side of the polarizer. The single transmittance of the polarizer is 40% or more and 45% or less. The Re(450) / Re(550) of the phase difference layer is 0.8 or more and less than 1. The barrier layer has an ammonia permeation amount of 70 g / m 2 • 24 h or less.

2. The polarizing plate with phase difference layer according to claim 1, wherein, The phase difference layer has an ammonia gas permeation amount of 70 g / m 2 • 24 h or less.

3. The polarizing plate with phase difference layer according to claim 1, wherein, The protective layer has an ammonia permeation amount of 70 g / m 2 • 24 h or less. The thickness of the polarizer is 10 μm or less.

5. The polarizing plate with a phase difference layer according to any one of claims 1 to 4, wherein, 8. The polarizing plate with a phase difference layer according to any one of claims 1 to 7, having a thickness of 150 μm or less.

6. The polarizing plate with phase difference layer according to any one of claims 1 to 5, wherein, 9. An organic electroluminescent display device comprising the polarizing plate with a phase difference layer according to any one of claims 1 to 8.

7. The polarizing plate with phase difference layer according to any one of claims 1 to 6, wherein, ​ ​ ​

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