Phase difference layer-containing polarizing plate and organic electroluminescence display device using the same

Abstract

To provide a retardation layer attached polarizing plate that remarkably suppresses discoloration when being applied to an organic EL display device.SOLUTION: A retardation layer attached polarizing plate 100 has a polarizer 11 and a block layer 30 arranged on one side of the polarizer and including a retardation layer 20. An amount of permeation of ammonia gas in the block layer is 70 g / m2 24 h or less.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] In recent years, with the spread of thin displays, displays (organic EL display devices) equipped with organic EL panels have been proposed. Since the organic EL panel has a highly reflective metal layer, problems such as external light reflection and background reflection are likely to occur. Therefore, it is known to prevent these problems by providing a circular polarizing plate on the viewing side (for example, Patent Document 1 and Patent Document 2). However, the circular polarizing plate provided in the organic EL display device has a problem of being easily decolorized.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present invention has been made to solve the above-described conventional problems, and a main object thereof is to provide a polarizing plate with a retardation layer in which decolorization is significantly suppressed when applied to an organic EL display device.

Means for Solving the Problems

[0005] According to an embodiment of the present invention, a polarizing plate with a retardation layer is provided. The polarizing plate with a retardation layer has a polarizer and a block layer disposed on one side of the polarizer and including a retardation layer, and the permeation amount of ammonia gas through the block layer is 70 g / m 2 ·24 h or less. In one embodiment, the ammonia gas permeation rate of the retardation layer is 70 g / m 2 ·24 h or less. In one embodiment, the block layer includes a protective layer for the polarizer. In one embodiment, the ammonia gas permeation rate of the protective layer is 70 g / m 2 ·24 h or less. In one embodiment, the polarizer with a retardation layer has a protective layer disposed on the other side of the polarizer. In one embodiment, the single transmittance of the polarizer is 40% or more and 45% or less. In one embodiment, Re(450) / Re(550) of the retardation layer is 0.8 or more and less than 1. In one embodiment, the thickness of the polarizer is 10 μm or less. In one embodiment, the thickness of the polarizer with a retardation layer is 150 μm or less. According to another aspect of the present invention, an organic electroluminescence display device is provided. This organic electroluminescence display device has the above-mentioned polarizer with a retardation layer.

Advantages of the Invention

[0006] According to an embodiment of the present invention, in a polarizer with a retardation layer, by providing a layer that satisfies a predetermined ammonia gas permeation rate on one side of the polarizer, a polarizer with a retardation layer in which decoloration is significantly suppressed when applied to an organic EL display device can be realized.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0008] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to these embodiments.

[0009] (Definition of Terms and Symbols) The definitions of the terms and symbols in this specification are as follows. (1) Refractive Index (nx, ny, nz) “nx” is the refractive index in the direction where the in-plane refractive index is maximum (i.e., the slow axis direction), “ny” is the refractive index in the direction orthogonal to the slow axis in the plane (i.e., the fast axis direction), and “nz” is the refractive index in the thickness direction. (2) In-Plane Phase Difference (Re) “Re(λ)” is the in-plane phase difference measured with light of wavelength λ nm at 23°C. For example, “Re(550)” is the in-plane phase difference measured with light of wavelength 550 nm at 23°C. Re(λ) is obtained by the formula: Re(λ) = (nx - ny) × d, where d (nm) is the thickness of the layer (film). (3) Phase Difference in the Thickness Direction (Rth) “Rth(λ)” is the phase difference in the thickness direction measured with light of wavelength λ nm at 23°C. For example, “Rth(550)” is the phase difference in the thickness direction measured with light of wavelength 550 nm at 23°C. Rth(λ) is obtained by the formula: Rth(λ) = (nx - nz) × d, where d (nm) is the thickness of the layer (film). (4) Nz Coefficient The Nz coefficient is obtained by Nz = Rth / Re. (5) Angle When referring to an angle in this specification, the angle includes both clockwise and counterclockwise directions with respect to the reference direction. Therefore, for example, “45°” means ±45°.

[0010] A. Polarizing Plate with a Phase Difference Layer FIG. 1 is a schematic cross-sectional view showing a schematic configuration of a polarizing plate with a retardation layer according to one embodiment of the present invention. The polarizing plate 100 with a retardation layer has a polarizer 11, a protective layer (visually recognizable side protective layer) 12 disposed on the visually recognizable side of the polarizer 11, and a block layer 30 disposed on the side opposite to the visually recognizable side of the polarizer 11. The block layer 30 includes a protective layer (inner protective layer) 13 of the polarizer and a retardation layer 20 in this order from the visually recognizable side. Thus, although the protective layer 13 is disposed on the side opposite to the visually recognizable side of the polarizer 11, the protective layer 13 may be omitted depending on the purpose and the like. Specifically, the block layer 30 may not include the protective layer 13. For example, when the retardation layer 20 is formed of a stretched film of a resin film and can also serve as a protective layer of the polarizer, the protective layer 13 may be omitted. On the other hand, when the retardation layer 20 is an alignment solidification layer of a liquid crystal compound, typically, the protective layer 13 is disposed. The retardation layer 20 may be a single layer or may have a laminated structure in which two or more layers are laminated. Note that a laminate of a polarizer and a protective layer is referred to as a polarizing plate. In the illustrated example, the polarizing plate 10 has a polarizer 11 and protective layers 12 and 13.

[0011] The thickness of the polarizing plate with a retardation layer (the thickness from the visually recognizable side protective layer to the retardation layer) is preferably 150 μm or less, more preferably 120 μm or less, still more preferably 100 μm or less, and particularly preferably 80 μm or less. The lower limit of the thickness of the polarizing plate with a retardation layer is preferably 20 μm, more preferably 45 μm. Such a polarizing plate with a retardation layer can have, for example, excellent flexibility and bending durability. As a result, the polarizing plate with a retardation layer can be applied to an organic EL display device capable of being curved, bent, folded, wound, or the like.

[0012] Although not shown, the polarizing plate with a retardation layer may further have other functional layers. The type, characteristics, number, combination, arrangement, etc. of the functional layers that the polarizing plate with a retardation layer can have can be appropriately set according to the purpose. For example, the polarizing plate with a retardation layer may further have a conductive layer or an isotropic substrate with a conductive layer. The polarizing plate with a retardation layer having a conductive layer or an isotropic substrate with a conductive layer is applied, for example, to an organic EL display device in which a touch sensor is incorporated inside the organic EL panel. As another example, the polarizing plate with a retardation layer may further have other retardation layers. The optical characteristics (e.g., refractive index characteristics, in-plane retardation, Nz coefficient, photoelastic coefficient), thickness, arrangement, etc. of the other retardation layers can be appropriately set according to the purpose. As a specific example, on the viewing side of the polarizing plate 10, other retardation layers (typically, a layer that imparts an (elliptical) polarization function, a layer that imparts an ultra-high retardation) that improve the visibility when viewing through polarized sunglasses may be provided. By having such a layer, excellent visibility can be realized even when the display screen is viewed through a polarizing lens such as polarized sunglasses. Therefore, the obtained polarizing plate (polarizing plate with a retardation layer) can also be suitably applied to an image display device used outdoors.

[0013] Each member constituting the polarizing plate with a retardation layer can be laminated via any appropriate adhesive layer (not shown). Specific examples of the adhesive layer include an adhesive layer and a pressure-sensitive adhesive layer. Specifically, the retardation layer 20 may be bonded to the polarizer 11 or the protective layer 13 via an adhesive layer (preferably, using an active energy ray-curable adhesive), or may be bonded to the polarizer 11 or the protective layer 13 via a pressure-sensitive adhesive layer (e.g., an acrylic pressure-sensitive adhesive). When the retardation layer 20 has a laminated structure of two or more layers, each retardation layer is bonded, for example, via an adhesive layer (preferably, using an active energy ray-curable adhesive). The block layer 30 may include an adhesive layer disposed between the polarizer 11 and the retardation layer 20.

[0014] Although not shown, in practice, an adhesive layer is provided on the side opposite to the side where the polarizer 11 of the retardation layer 20 is disposed (specifically, as the outermost layer on the side opposite to the viewing side), and the polarizing plate with a retardation layer can be attached to the organic EL panel body. Further, it is preferable that a release film (separator) is temporarily attached to the surface of the adhesive layer until the polarizing plate with a retardation layer is put into use. By temporarily attaching the release film, the adhesive layer is protected and the polarizing plate with a retardation layer can be formed into a roll.

[0015] The polarizing plate with a retardation layer may 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 long with respect to 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 a retardation layer in a long strip shape can be wound into a roll.

[0016] A-1. Block layer The block layer 30 has an ammonia gas 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, still more preferably 40 g / m 2 ·24 h or less, particularly preferably 30 g / m 2 ·24 h or less. By providing such a block layer, decolorization can be significantly suppressed. The inventors of the present invention faced a new problem that the polarizing plate with a retardation layer is decolorized when the polarizing plate with a retardation layer is applied to an organic EL display device, and as a result of intensive studies on this problem, it was found that the cause of decolorization is ammonia (substantially ammonium ions) derived from the members constituting the organic EL panel. By such a block layer 30, ammonia reaching the polarizer 11 can be blocked as much as possible, and decolorization can be significantly suppressed. Specifically, decomposition of the dichroic substance (typically, an iodine complex) contained in the polarizer can be suppressed. The ammonia gas permeation amount of the block layer 30 is, for example, 3.0 g / m 2 ·24 h or more.

[0017] The permeation amount of ammonia gas in the block layer 30 may be satisfied by at least one layer included in the block layer 30, or may be satisfied by a combination of two or more layers included in the block layer 30. Specifically, the permeation amount of ammonia gas in the block layer 30 may be achieved by the protective layer 13 of the polarizer 11, may be achieved by the retardation layer 20, may be achieved by the adhesive layer (for example, an adhesive layer), or may be achieved by a combination thereof. In one embodiment, the permeation amount of ammonia gas in both or either of the retardation layer 20 and the protective layer 13 is 70 g / m 2 ·24 h or less.

[0018] The permeation amount of the ammonia gas can be determined from the difference by measuring the permeation amount of an aqueous ammonia solution and the permeation amount of water.

[0019] A-2. Polarizer The polarizer is typically a film containing a dichroic substance (typically, iodine).

[0020] The thickness of the polarizer is, for example, preferably 15 μm or less, more preferably 12 μm or less, still more preferably 10 μm or less, and particularly preferably 8 μm or less from the viewpoint of thinning. On the other hand, the thickness of the polarizer is preferably 1 μm or more, more preferably 2 μm or more, and still more preferably 3 μm or more. If the thickness of the polarizer is within such a range, curling during heating can be suppressed well, and good appearance durability during heating can be obtained.

[0021] The polarizer preferably exhibits absorption dichroism at any wavelength in the range of 380 nm to 780 nm. The single transmittance of the polarizer is, for example, 40.0% or more, preferably 41.5% or more, more preferably 43.0% or more, and still more preferably 44.5% or more. On the other hand, the single transmittance is, for example, 46.0% or less, and may be 45.0% or less. The degree of polarization of the polarizer is preferably 97.0% or more, more preferably 99.0% or more, and still more preferably 99.9% or more.

[0022] The polarizer can be produced by any suitable method. Specifically, the polarizer may be produced from a single-layer resin film or may be produced using a laminate of two or more layers.

[0023] The method for manufacturing a polarizer from the above single-layer resin film typically includes subjecting the resin film to a dyeing treatment with a dichroic substance such as iodine or a dichroic dye and a stretching treatment. As the resin film, for example, a hydrophilic polymer film such as a polyvinyl alcohol (PVA) - based film, a partially formalized PVA - based film, or a partially saponified ethylene - vinyl acetate copolymer - based film is used. Preferably, since it has excellent optical properties, a PVA - based film is dyed with iodine and uniaxially stretched to obtain a polarizer.

[0024] The dyeing with iodine is performed, for example, by immersing the PVA - based film in an iodine aqueous solution. The stretching ratio of the uniaxial stretching is preferably 3 to 7 times. The stretching may be performed after dyeing, may be performed while dyeing, or may be performed after stretching and then dyeing. If necessary, the PVA - based film is subjected to a swelling treatment, a cross - linking treatment, a washing treatment, a drying treatment, etc. For example, by immersing the PVA - based film in water and washing it before dyeing, not only can the dirt on the surface of the PVA - based film and the anti - blocking agent be washed away, but also the PVA - based film can be swollen to prevent uneven dyeing.

[0025] As specific examples of the polarizer obtained using the above laminate, there may be mentioned a laminate of a resin substrate and a PVA-based resin layer (PVA-based resin film) laminated on the resin substrate, or a polarizer obtained using a laminate of a resin substrate and a PVA-based resin layer formed by coating on the resin substrate. The polarizer obtained using a laminate of a resin substrate and a PVA-based resin layer formed by coating on the resin substrate can be produced, for example, by applying a PVA-based resin solution to the resin substrate and drying it to form a PVA-based resin layer on the resin substrate to obtain a laminate of the resin substrate and the PVA-based resin layer; stretching and dyeing the laminate to make the PVA-based resin layer a polarizer. In the present embodiment, preferably, a PVA-based resin layer containing a halide and a polyvinyl alcohol-based resin is formed on one side of the resin substrate. Stretching typically includes immersing the laminate in an aqueous boric acid solution and stretching it. Further, stretching may further include air stretching the laminate at a high temperature (for example, 95° C. or higher) before stretching in the aqueous boric acid solution, if necessary. In addition, in the present embodiment, preferably, the laminate is subjected to a dry shrinkage treatment in which it is heated while being conveyed in the longitudinal direction to shrink by 2% or more in the width direction. Typically, the manufacturing method of the present embodiment includes subjecting the laminate to an air-assisted stretching treatment, a dyeing treatment, an underwater stretching treatment, and a dry shrinkage treatment in this order. By introducing the auxiliary stretching, even when PVA is applied on a thermoplastic resin, it becomes possible to enhance the crystallinity of PVA and achieve high optical properties. At the same time, by enhancing the orientation of PVA in advance, problems such as a decrease in the orientation of PVA or dissolution when immersed in water in the subsequent dyeing step or stretching step can be prevented, and high optical properties can be achieved. Further, when the PVA-based resin layer is immersed in a liquid, compared with the case where the PVA-based resin layer does not contain a halide, the disturbance of the orientation of polyvinyl alcohol molecules and the decrease in the orientation can be suppressed. Thereby, the optical properties of the polarizer obtained through treatment steps such as a dyeing treatment and an underwater stretching treatment, which are performed by immersing the laminate in a liquid, can be improved. Further, by shrinking the laminate in the width direction by the dry shrinkage treatment, the optical properties can be improved.The obtained resin substrate / polarizer laminate may be used as it is (i.e., the resin substrate may be used as the protective layer of the polarizer), or an arbitrary appropriate protective layer according to the purpose may be laminated on the peeled surface of the resin substrate peeled from the resin substrate / polarizer laminate or on the surface opposite to the peeled surface and used. Details of such a method for manufacturing a polarizer are described, for example, in JP-A-2012-73580 and Japanese Patent No. 6470455. The entire descriptions of these publications are incorporated herein by reference.

[0026] A-3. Protective Layer The above protective layer is composed of any appropriate film that can be used as the protective layer of the polarizer. Examples of the material constituting the protective layer include cellulose resins such as triacetyl cellulose (TAC), cycloolefin resins such as polynorbornene, (meth)acrylic resins, polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyolefin resins such as polyethylene, and polycarbonate resins. Representative examples of the (meth)acrylic resin include (meth)acrylic resins having a lactone ring structure. (Meth)acrylic resins having a lactone ring structure are described, for example, in JP-A-2000-230016, JP-A-2001-151814, JP-A-2002-120326, JP-A-2002-254544, and JP-A-2005-146084. The entire descriptions of these publications are incorporated herein by reference.

[0027] The retardation layer - equipped polarizing plate is typically disposed on the viewing side of the organic EL display device, and the viewing - side protective layer 12 may be subjected to surface treatments such as hard - coat treatment, antireflection treatment, anti - sticking treatment, and antiglare treatment as required.

[0028] The thickness of the viewing - side protective layer 12 can be appropriately set. The thickness of the viewing - side protective layer 12 is preferably 10 μm to 80 μm, more preferably 15 μm to 70 μm, and even more preferably 20 μm to 50 μm. When a surface treatment is performed, the thickness of the viewing - side protective layer 12 is the thickness including the thickness of the surface treatment layer.

[0029] In one embodiment, the permeation amount of ammonia gas through the protective layer 13 is 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, still more preferably 40 g / m 2 ·24 h or less, particularly preferably 30 g / m 2 ·24 h or less. In this case, as the material constituting the protective layer 13, at least one selected from cellulose-based resins, cycloolefin-based resins, and polyester-based resins is preferably used.

[0030] In one embodiment, the protective layer 13 is preferably optically isotropic. As used herein, "optically isotropic" means that the in-plane retardation Re(550) is 0 nm to 10 nm and the retardation in the thickness direction Rth(550) is -10 nm to +10 nm. The thickness of the protective layer 13 can be appropriately set according to, for example, the desired permeation amount of ammonia gas. The thickness of the protective layer 13 is preferably 10 μm to 80 μm, more preferably 20 μm to 70 μm, and still more preferably 30 μm to 50 μm. When the retardation layer 20 is a stretched film of a resin film, for example, from the viewpoint of thinning, the protective layer 13 may be omitted.

[0031] A-4. Retardation layer The retardation layer 20 may be a single layer or may have a laminated structure (substantially a two-layer structure).

[0032] When the retardation layer 20 is a single layer, the retardation layer 20 can typically function as a λ / 4 plate. The retardation layer is typically provided to impart antireflection characteristics to the organic EL display device. The retardation layer typically exhibits a refractive index characteristic showing the relationship of 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 even more preferably 120 nm to 160 nm. Here, "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 a range that does not impair the effects of the present invention, ny > nz or ny < nz may occur.

[0033] The Nz coefficient of the retardation layer is preferably 0.9 to 1.5, more preferably 0.9 to 1.3. By satisfying such a relationship, an organic EL display device having a very excellent reflection hue can be obtained.

[0034] When the retardation layer is a single layer, the retardation layer preferably exhibits an inverse dispersion wavelength characteristic in which the retardation value increases according to the wavelength of the measurement light. In this case, Re(450) / Re(550) of the retardation layer is preferably 0.8 or more and less than 1, more preferably 0.8 or more and 0.95 or less. With such a configuration, very excellent antireflection characteristics can be realized.

[0035] The angle formed between the slow axis of the retardation layer and the absorption axis of the polarizer is preferably 40° to 50°, more preferably 42° to 48°, and even more preferably about 45°. If the angle is within such a range, by using the retardation layer as a λ / 4 plate as described above, an organic EL display device having very excellent antireflection characteristics can be obtained.

[0036] The retardation layer can be composed of any appropriate material as long as it can satisfy the above characteristics. Specifically, the retardation layer may be a stretched film of a resin film or an alignment cured layer of a liquid crystal compound (hereinafter referred to as a liquid crystal alignment cured layer).

[0037] When the phase difference layer is a stretched film of a resin film, representative examples of the resin constituting the resin film include polycarbonate resins or polyester carbonate resins (hereinafter sometimes simply referred to as polycarbonate resins). As the polycarbonate resin, any appropriate polycarbonate resin can be used as long as the desired moisture permeability can be obtained. For example, the polycarbonate resin includes a structural unit derived from a fluorene-based dihydroxy compound, a structural unit derived from an isosorbide-based dihydroxy compound, an alicyclic diol, an alicyclic dimethanol, di-, tri- or polyethylene glycol, and a structural unit derived from at least one dihydroxy compound selected from the group consisting of alkylene glycol or spiro glycol. Preferably, the polycarbonate resin includes a structural unit derived from a fluorene-based dihydroxy compound, a structural unit derived from an isosorbide-based dihydroxy compound, a structural unit derived from an alicyclic dimethanol and / or a structural unit derived from di-, tri- or polyethylene glycol; more preferably, it includes a structural unit derived from a fluorene-based dihydroxy compound, a structural unit derived from an isosorbide-based dihydroxy compound, and a structural unit derived from di-, tri- or polyethylene glycol. The polycarbonate resin may optionally include structural units derived from other dihydroxy compounds. The phase difference layer can be formed by stretching a film composed of the polycarbonate resin as described above under any appropriate stretching conditions. The details of the polycarbonate resin and the method for forming the phase difference layer are described, for example, in JP-A Nos. 2014-10291, 2014-26266, 2015-212816, 2015-212817, 2015-212818, 2017-54093, and 2018-60014. The descriptions of these publications are incorporated herein by reference.

[0038] When the retardation layer is a liquid crystal alignment solidification layer, by using a liquid crystal compound, the difference between nx and ny of the obtained retardation layer can be made significantly larger than that of a non-liquid crystal material. Therefore, the thickness of the retardation layer for obtaining a desired in-plane retardation can be made significantly smaller. As a result, further thinning of the polarizing plate with a retardation layer (and as a result, the organic EL display device) can be achieved. In this specification, the "alignment solidification layer" refers to a layer in which a liquid crystal compound is aligned in a predetermined direction within the layer and the alignment state is fixed. Note that the "alignment solidification layer" is a concept that includes an alignment cured layer obtained by curing a liquid crystal monomer. In the present embodiment, typically, rod-shaped liquid crystal compounds are aligned in a state aligned in the slow axis direction of the retardation layer (homogeneous alignment). Specific examples of the liquid crystal compound and details of the method for forming the liquid crystal alignment solidification layer are described, for example, in JP-A-2006-163343 and JP-A-2006-178389. The descriptions in these publications are incorporated herein by reference.

[0039] The thickness of the retardation layer can typically be set to a thickness that can function appropriately as a λ / 4 plate. When the retardation layer is a stretched film of a resin film, the thickness of the retardation layer can be, for example, 10 μm to 60 μm. When the retardation layer is a liquid crystal alignment solidification layer, the thickness of the retardation layer can be, for example, 1 μm to 5 μm.

[0040] When the retardation layer 20 has a laminated structure, the retardation layer typically has a two-layer structure of a first liquid crystal alignment solidified layer and a second liquid crystal alignment solidified layer. In this case, either the first liquid crystal alignment solidified layer or the second liquid crystal alignment solidified layer can function as a λ / 2 plate, and the other can function as a λ / 4 plate. Here, the case where the first liquid crystal alignment solidified layer can function as a λ / 2 plate and the second liquid crystal alignment solidified layer can function as a λ / 4 plate will be described, but these may be reversed. The thickness of the first liquid crystal alignment solidified layer can be adjusted so as to obtain a desired in-plane retardation of the λ / 2 plate, and can be, for example, 2.0 μm to 4.0 μm. The thickness of the second liquid crystal alignment solidified layer can be adjusted so as to obtain a desired in-plane retardation of the λ / 4 plate, and can be, for example, 1.0 μm to 2.5 μm. The in-plane retardation Re(550) of the first liquid crystal alignment solidified layer is preferably 200 nm to 300 nm, more preferably 230 nm to 290 nm, and still more preferably 250 nm to 280 nm. The in-plane retardation Re(550) of the second liquid crystal alignment solidified layer is, as described above, preferably 100 nm to 190 nm, more preferably 110 nm to 170 nm, and still more preferably 120 nm to 160 nm. The angle formed by the slow axis of the first liquid crystal alignment solidified layer and the absorption axis of the polarizer is preferably 10° to 20°, more preferably 12° to 18°, and still more preferably about 15°. The angle formed by the slow axis of the second liquid crystal alignment solidified layer and the absorption axis of the polarizer is preferably 70° to 80°, more preferably 72° to 78°, and still more preferably about 75°. With such a configuration, it is possible to obtain characteristics close to ideal inverse wavelength dispersion characteristics, and as a result, very excellent antireflection characteristics can be realized.

[0041] In one embodiment, the ammonia gas permeation amount of the retardation layer 20 is 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, still more preferably 40 g / m 2 ·24 h or less, particularly preferably 30 g / m 2· It is less than 24 h. In this case, as the retardation layer 20, preferably, the stretched film of the above resin film is used. As a constituent material of the protective layer 13 combined with the retardation layer 20 which is a stretched film of a resin film, it is preferable to use at least one selected from a cycloolefin resin and a polyester resin. According to such a combination, decoloration can be extremely remarkably suppressed.

[0042] As a constituent material of the protective layer 13 combined with the retardation layer 20 which is a liquid crystal alignment cured layer, it is preferable to use a cellulose resin. According to such a combination, decoloration can be extremely remarkably suppressed.

[0043] B. Organic EL display device The polarizing plate with a retardation layer can be applied to an organic EL display device. Therefore, the organic EL display device according to an embodiment of the present invention has the polarizing plate with a retardation layer.

[0044] FIG. 2 is a schematic cross-sectional view showing an outline of a state where a polarizing plate with a retardation layer is disposed on an organic EL panel in an organic EL display device according to one embodiment of the present invention. The polarizing plate with a retardation layer 100 is disposed such that its block layer 30 is on the organic EL panel main body 40 side rather than the polarizer 11. Specifically, the polarizing plate with a retardation layer 100 is attached to the organic EL panel main body 40 via an adhesive layer (not shown). The organic EL panel main body 40 has a substrate 60, a circuit layer including a thin film transistor (TFT) or the like, an organic light emitting diode (OLED), and an upper structure layer 80 including a sealing film or the like for sealing the OLED. The upper structure layer 80 includes, for example, a nitrogen-containing layer (for example, a nitride layer), and ammonia (ammonium ions) can be generated from the upper structure layer 80. According to the polarizing plate with a retardation layer, decoloration can be remarkably suppressed in an organic EL display device. Further, the problem of decoloration can be solved without changing the design of the configuration of the organic EL panel main body.

[0045] For example, when a flexible substrate (for example, a resin substrate) is used as the substrate 60, the obtained organic EL display device can achieve bending, flexing, folding, winding, and the like.

Example

[0046] The present invention will be specifically described below with reference to examples, but the present invention is not limited by these examples. The measurement methods for each property are as follows. Unless otherwise specified, "parts" and "%" in the examples and comparative examples are based on weight. (1) Thickness For a thickness of 10 μm or less, it was measured using an interference film thickness meter (manufactured by Otsuka Electronics Co., Ltd., product name "MCPD-3000"). For a thickness exceeding 10 μm, it was measured using a digital micrometer (manufactured by Anritsu Corporation, product name "KC-351C"). (2) Permeation amount of ammonia gas Two cups A and B were prepared. 150 g of a 10% aqueous ammonia solution was placed in cup A, and 150 g of water was placed in cup B. The test piece (film) cut into a circle with a diameter of 6 cm was used to seal them. In this state, cups A and B were left standing in an oven (under atmospheric pressure) set at 40 °C for 24 hours, and the weight changes of cups A and B before and after standing were measured. The difference between the weight change amount of cup A (permeation amount of ammonia gas and water) and the weight change amount of cup B (permeation amount of water) was calculated to obtain the permeation amount of ammonia gas (g / m 2 ·24 h).

[0047] [Example 1] 1. Preparation of polarizer As the thermoplastic resin substrate, an amorphous isophthalic copolyethylene terephthalate film (thickness: 100 μm) in a long strip shape with a water absorption rate of 0.75% and a Tg of about 75 °C was used. One side of the resin substrate was subjected to corona treatment. 13 parts by weight of potassium iodide was added to 100 parts by weight of a PVA-based resin obtained by mixing polyvinyl alcohol (degree of polymerization 4200, saponification degree 99.2 mol%) and acetoacetyl-modified PVA (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., product name "Gosefimer Z410") in a ratio of 9:1, and the mixture was dissolved in water to prepare a PVA aqueous solution (coating solution). The above PVA aqueous solution was applied to 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 producing a laminate. The obtained laminate was uniaxially stretched 2.4 times in the longitudinal direction (length direction) between rolls with different peripheral speeds in an oven at 130°C with free ends (air-assisted stretching treatment). Next, the laminate was immersed in an insolubilization bath at a liquid temperature of 40°C (an aqueous boric acid solution obtained by mixing 4 parts by weight of boric acid with 100 parts by weight of water) for 30 seconds (insolubilization treatment). Next, the laminate was immersed in a dyeing bath at a liquid temperature of 30°C (an aqueous iodine solution obtained by mixing iodine and potassium iodide in a weight ratio of 1:7 with 100 parts by weight of water) for 60 seconds while adjusting the concentration so that the single transmittance (Ts) of the finally obtained polarizing film was 43.0% (dyeing treatment). Next, the laminate was immersed in a crosslinking bath at a liquid temperature of 40°C (an aqueous boric acid 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). Thereafter, while immersing the laminate in an aqueous boric acid solution at a liquid temperature of 70°C (boric acid concentration 4.0% by weight, potassium iodide 5.0% by weight), uniaxial stretching was performed in the longitudinal direction (length direction) between rolls with different peripheral speeds so that the total stretching ratio was 5.5 times (stretching treatment in water). Thereafter, the laminate was immersed in a washing bath at a liquid temperature of 20°C (an aqueous solution obtained by mixing 4 parts by weight of potassium iodide with 100 parts by weight of water) (washing treatment). Thereafter, while drying in an oven maintained at 90°C, it was brought into contact with a SUS heating roll maintained at a surface temperature of 75°C for about 2 seconds (dry shrinkage treatment). The shrinkage rate in the width direction of the laminate by the dry shrinkage treatment was 5.2%. In this way, a polarizer with a thickness of 5 μm was formed on the resin substrate.

[0048] 2. Production of a polarizing plate A TAC film with a thickness of 25 μm was laminated onto the surface of the polarizer of the resin substrate / polarizer laminate obtained above via an ultraviolet curable adhesive. Specifically, the curable adhesive was applied so that its thickness became 1.0 μm, and they were laminated using a roll machine. Then, UV light was irradiated from the TAC film side to cure the adhesive. Next, the resin substrate was peeled off from the polarizer, and a cycloolefin-based resin film (thickness 13 μm, ammonia gas permeation amount 54 g / m 2 ·24 h: hereinafter referred to as COP film) was laminated in the same manner as above. In this way, a polarizing plate having a configuration of TAC film / polarizer / COP film was obtained.

[0049] 3. Production of the retardation film constituting the retardation layer 3-1. Polymerization of polyester carbonate-based resin Polymerization was carried out using a batch polymerization apparatus consisting of two vertical reactors equipped with stirring blades and a reflux condenser controlled at 100 °C. 29.60 parts by mass (0.046 mol) of bis[9-(2-phenoxycarbonylethyl)fluorene-9-yl]methane, 29.21 parts by mass (0.200 mol) of isosorbide (ISB), 42.28 parts by mass (0.139 mol) of spiroglycol (SPG), 63.77 parts by mass (0.298 mol) of diphenyl carbonate (DPC), and 1.19×10 -2 parts by mass (6.78×10 -5(A certain number of moles) were charged. After replacing the inside of the reactor with nitrogen under reduced pressure, it was heated with a heat medium, and stirring was started when the internal temperature reached 100°C. After 40 minutes from the start of temperature increase, the internal temperature reached 220°C, and while controlling to maintain this temperature, reduced pressure was started and it was made 13.3 kPa in 90 minutes after reaching 220°C. The phenol vapor by-produced along with the polymerization reaction was led to a reflux condenser at 100°C, the monomer components contained in a small amount in the phenol vapor were returned to the reactor, and the phenol vapor that did not condense was led to a condenser at 45°C and recovered. Nitrogen was introduced into the first reactor to once restore the pressure to atmospheric pressure, and then the oligomerized reaction solution in the first reactor was transferred to the second reactor. Next, heating and reduced pressure in the second reactor were started, and the internal temperature was made 240°C and the pressure was made 0.2 kPa in 50 minutes. Thereafter, the polymerization was allowed to proceed until a predetermined stirring power was reached. When the predetermined power was reached, nitrogen was introduced into the reactor to restore the pressure, and the produced polyester carbonate resin was extruded into water, and the strands were cut to obtain pellets.

[0050] 3-2. Preparation of the retardation film The obtained polyester carbonate resin (pellets) was vacuum dried at 80°C for 5 hours, and then a film forming apparatus equipped with a single screw extruder (manufactured by 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 - 130°C) and a winder was used to produce a long resin film with a thickness of 135 μm. The obtained 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 retardation film with a thickness of 47 μm. Re(550) of the obtained retardation film was 141 nm, Re(450) / Re(550) was 0.82, and the Nz coefficient was 1.12. Also, the permeation amount of ammonia gas of the obtained retardation film was 10 g / m 2 ·24 h.

[0051] 4. Preparation of the adhesive 4-1. Preparation of the acrylic polymer A monomer mixture containing 91 parts of butyl acrylate, 6 parts of acryloyl morpholine (ACMO), 2.7 parts of acrylic acid and 0.3 part of 4-hydroxybutyl acrylate was charged into a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube and a cooler. Further, 0.1 part of 2,2'-azobisisobutyronitrile as a polymerization initiator was charged together with 100 parts of ethyl acetate per 100 parts of this monomer mixture, and nitrogen gas was introduced while gently stirring for nitrogen substitution. After that, the polymerization reaction was carried out for 8 hours while maintaining the liquid temperature in the flask at around 55 °C to prepare an acrylic polymer solution.

[0052] 4-2. Preparation of Adhesive To 100 parts of the solid content of the obtained acrylic polymer solution, 0.1 part of trimethylolpropane / toluene diisocyanate adduct (manufactured by Tosoh Corporation, trade name "Coronate L"), 0.3 part of a peroxide crosslinking agent (benzoyl peroxide) and 0.2 part of an epoxy group-containing silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "KBM-403") were blended to obtain an adhesive. The permeation amount of ammonia gas of the obtained adhesive (thickness 20 μm) was 118 g / m 2 ·24 h.

[0053] 5. Production of Polarizing Plate with Retardation Layer The retardation film obtained in the above 3. was laminated on the COP film surface of the polarizing plate obtained in the above 2. through the adhesive (thickness 20 μm) obtained in the above 4. At this time, it was laminated so that the absorption axis of the polarizer and the slow axis of the retardation film formed an angle of 45°. In this way, a polarizing plate with a retardation layer was obtained.

[0054] [Example 2] In the production of the polarizing plate, a PET film (thickness 30 μm, ammonia gas permeation amount 53 g / m 2 ·24 h) was used instead of the COP film, and a polarizing plate with a retardation layer was obtained in the same manner as in Example 1.

[0055] [Example 3] In the production of the polarizing plate, a TAC film (thickness 25 μm, ammonia gas permeation amount 30 g / m 2 ·24 h) was used instead of the COP film, and a retardation layer - attached polarizing plate was obtained in the same manner as in Example 1.

[0056] [Example 4] In the production of the polarizing plate, an acrylic film having a lactone ring structure (thickness 20 μm, ammonia gas permeation amount 78 g / m 2 ·24 h) was used instead of the COP film, and a retardation layer - attached polarizing plate was obtained in the same manner as in Example 1.

[0057] [Example 5] In the production of the polarizing plate, a COP film was not laminated to the polarizer using an ultraviolet - curable adhesive, and a retardation layer - attached polarizing plate was obtained in the same manner as in Example 1.

[0058] [Example 6] A retardation layer - attached polarizing plate was obtained in the same manner as in Example 1, except that the following liquid crystal alignment curing layer was used as the retardation layer.

[0059] (Production of the liquid crystal alignment curing layer constituting the retardation layer) 55 parts of the compound represented by the formula (I), 25 parts of the compound represented by the formula (II), and 20 parts of the compound represented by the formula (III) were added to 400 parts of cyclopentanone (CPN), and then heated to 60 °C and stirred to dissolve. After dissolution was confirmed, the temperature was returned to room temperature, and 3 parts of Irgacure 907 (manufactured by BASF Japan Ltd.), 0.2 part of Megafac F-554 (manufactured by DIC Corporation), and 0.1 part of p-methoxyphenol (MEHQ) were added, followed by further stirring to obtain a solution. The solution was transparent and homogeneous. The obtained solution was filtered through a 0.20 μm membrane filter to obtain a polymerizable composition. On the other hand, a polyimide solution for an alignment film was applied to a glass substrate with a thickness of 0.7 mm using a spin coating method, dried at 100 °C for 10 minutes, and then fired at 200 °C for 60 minutes to obtain a coating film. The obtained coating film was subjected to a rubbing treatment to form an alignment film. The rubbing treatment was performed using a commercially available rubbing apparatus. The polymerizable composition obtained above was applied to the substrate (substantially the alignment film) by a spin coating method and dried at 100 °C for 2 minutes. After the obtained coating film was cooled to room temperature, ultraviolet rays were irradiated for 30 seconds at an intensity of 30 mW / cm 2 to obtain a liquid crystal alignment cured layer. 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 exhibited reverse dispersion wavelength characteristics. Also, the permeation amount of ammonia gas through the obtained liquid crystal alignment cured layer was 103 g / m 2 ·24 h.

[0060] [Chemical formula] [Chemical formula]

[0061] [Example 7] In the production of a polarizing plate, instead of a COP film, a TAC film (thickness 25 μm, ammonia gas permeation amount 30 g / m 2· Using it for 24 hours), and using the above liquid crystal alignment cured layer as the retardation layer, when laminating to the polarizing plate, a polarizing plate with a retardation layer was obtained in the same manner as in Example 1 except that an ultraviolet curable adhesive (thickness 1.0 μm) was used instead of the above adhesive.

[0062] [Comparative Example 1] In the production of the polarizing plate, a 40-μm-thick TAC film was used instead of the 25-μm-thick TAC film, and an acrylic film having a lactone ring structure (thickness 20 μm, ammonia gas permeation amount 78 g / m 2 · Using it for 24 hours), and obtaining a polarizing plate with a retardation layer in the same manner as in Example 1 except that the above liquid crystal alignment cured layer was used as the retardation layer.

[0063] [Comparative Example 2] In the production of the polarizing plate, a 40-μm-thick TAC film was used instead of the 25-μm-thick TAC film, and a polarizing plate with a retardation layer was obtained in the same manner as in Example 5 except that the above liquid crystal alignment cured layer was used as the retardation layer.

[0064] [Comparative Example 3] In the production of the polarizing plate, an acrylic film having a lactone ring structure (thickness 20 μm) was used instead of the 25-μm-thick TAC film, and an acrylic film having a lactone ring structure (thickness 20 μm, ammonia gas permeation amount 78 g / m 2 · Using it for 24 hours), and obtaining a polarizing plate with a retardation layer in the same manner as in Example 1 except that the above liquid crystal alignment cured layer was used as the retardation layer.

[0065] The following evaluations were performed on the examples and comparative examples. The evaluation results are summarized in Table 1 together with the configuration of the polarizing plate with a retardation layer (block layer). <Evaluation> 〇Single transmittance and degree of polarization For the polarizing plates of the examples and comparative examples, the single transmittance Ts, parallel transmittance Tp, and orthogonal transmittance Tc measured using an ultraviolet-visible spectrophotometer ("LPF-2000" manufactured by Otsuka Electronics Co., Ltd.) were taken as the Ts, Tp, and Tc of the polarizer, respectively. These Ts, Tp, and Tc are Y values that were measured with a 2-degree field of view (C light source) in JIS Z8701 and subjected to visual sensitivity correction. From the obtained Tp and Tc, the degree of polarization P was determined by the following formula. Degree of polarization P (%) = {(Tp - Tc) / (Tp + Tc)} 1 / 2 × 100 〇Ammonia decolorization test Put 10 g of a 10% aqueous ammonia solution into a glass bottle (cylindrical with a diameter of 30 mm and a depth of 50 mm), cover the opening of the glass bottle with the retardation film-attached polarizing plate obtained in the examples and comparative examples (with the retardation film in contact with the opening), seal it, and heat the glass bottle at 65 °C for 2 hours in this state. After heating, measure the degree of polarization at the location corresponding to the opening of the glass bottle. Taking the degree of polarization before heating of the retardation film-attached polarizing plate (substantially the polarizer) as P and the degree of polarization after heating as P', ΔP was calculated from the following formula. The smaller ΔP is, the more the decolorization by ammonia is suppressed. ΔP = P - P'

[0066]

Table 1

[0067] In the examples, ΔP is less than 20%, and a retardation film-attached polarizing plate can be obtained in which the degree of polarization hardly changes (does not decolorize) even when exposed to ammonia. On the other hand, in the comparative examples, it was confirmed that the degree of polarization decreased significantly and the polarization function almost disappeared in some cases.

Industrial applicability

[0068] The retardation film-attached polarizing plate of the present invention is suitably used, for example, as a circular polarizing plate for antireflection of an organic EL display device.

Explanation of symbols

[0069] 10 Polarizing plate 11 Polarizer 12 Protective layer (visible side protective layer) 13 Protective layer (inner protective layer) 20 Retardation layer 30 Block layer 100 Polarizing plate with retardation layer

Claims

1. A polarizer, and a block layer disposed on one side of the polarizer and including a protective layer and a retardation layer of the polarizer. The protective layer is made of a polyester resin, the retardation layer is made of a polycarbonate resin, the ammonia gas permeation amount of the block layer is 70 g / m ２ ·24 h or less, A polarizing plate with a retardation layer.

2. The ammonia gas permeation amount of the retardation layer is 70 g / m ２ ·24 h or less. The polarizing plate with a retardation layer according to claim 1.

3. The ammonia gas permeation amount of the protective layer is 70 g / m ２ ·24 h or less. The polarizing plate with a retardation layer according to claim 1 or 2.

4. Having a protective layer disposed on the other side of the polarizer. The polarizing plate with a retardation layer according to any one of claims 1 to 3.

5. The single transmittance of the polarizer is 40% or more and 45% or less. The polarizing plate with a retardation layer according to any one of claims 1 to 4.

6. Re(450) / Re(550) of the retardation layer is 0.8 or more and less than 1. The polarizing plate with a retardation layer according to any one of claims 1 to 5.

7. The thickness of the polarizer is 10 μm or less. The polarizing plate with a retardation layer according to any one of claims 1 to 6.

8. The thickness is 150 μm or less. The polarizing plate with a retardation layer according to any one of claims 1 to 7.

9. An organic electroluminescence display device having the polarizing plate with a retardation layer according to any one of claims 1 to 8.

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