Polarizing plate with retarding layer and organic electroluminescence display device utilize this polarizing plate.

Abstract

The invention relates to a polarizing plate with a delay layer which is substantially prevented from fading when applied to an organic EL display device. The polarizing plate with a delay layer in the design of the invention consists of: a polarizer; and a bulk layer arranged on one side of the polarizer, the bulk layer comprising the delay layer, wherein the bulk layer has an ammonia gas permeability of 70 g / m2.24 hours or less. The invention also relates to an organic electroluminescent display device using this polarizing plate.

Description

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

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

[0002] In recent years, with the spread of thin displays, displays equipped with organic EL panels (organic EL display devices) have been proposed. Because organic EL panels have a highly reflective metal layer, they are prone to problems such as reflection of external light and glare of the background. It is known that providing a circular polarizer on the viewing side can prevent these problems (see, for example, Patent Documents 1 and 2). However, circular polarizers provided in organic EL display devices have the problem of being easily discolored.

[0003] JP 2002-372622 A Japanese Patent No. 3325560 A

[0004] The present invention has been made to solve the above-mentioned conventional problems, and its main object is to provide a polarizing plate with a retardation layer that significantly suppresses discoloration when applied to an organic EL display device.

[0005] According to an embodiment of the present invention, there is provided a polarizing plate with a retardation layer, which comprises a polarizer and a blocking layer including a retardation layer and disposed on one side of the polarizer, and the blocking layer has an ammonia gas permeability of 70 g / m ２ In one embodiment, the ammonia gas permeation amount of the retardation layer is 70 g / m ２ In one embodiment, the blocking layer includes a protective layer for the polarizer. In one embodiment, the ammonia gas permeation amount of the protective layer is 70 g / m ２24 hours or less. In one embodiment, the retardation layer-attached polarizing plate has a protective layer disposed on the other side of the polarizer. In one embodiment, the polarizer has a single transmittance of 40% or more and 45% or less. In one embodiment, the retardation layer has an Re(450) / Re(550) ratio of 0.8 or more and less than 1. In one embodiment, the polarizer has a thickness of 10 μm or less. In one embodiment, the retardation layer-attached polarizing plate has a thickness of 150 μm or less. According to another aspect of the present invention, there is provided an organic electroluminescence display device. The organic electroluminescence display device has the retardation layer-attached polarizing plate.

[0006] According to an embodiment of the present invention, by providing a layer that satisfies a predetermined ammonia gas permeability on one side of the polarizer in a polarizing plate with a retardation layer, it is possible to realize a polarizing plate with a retardation layer that significantly suppresses discoloration when applied to an organic EL display device.

[0007] 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, and FIG. 2 is a schematic cross-sectional view showing an outline of a state in which 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.

[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 terms and symbols used in this specification are as follows. (1) Refractive Index (nx, ny, nz) "nx" is the refractive index in the direction in which the in-plane refractive index is maximum (i.e., the slow axis direction), "ny" is the refractive index in the in-plane direction perpendicular to the slow axis (i.e., the fast axis direction), and "nz" is the refractive index in the thickness direction. (2) In-Plane Retardation (Re) "Re(λ)" is the in-plane retardation measured with light having a wavelength of λ nm at 23°C. For example, "Re(550)" is the in-plane retardation measured with light having a wavelength of 550 nm at 23°C. Re(λ) is calculated by the formula: Re(λ) = (nx - ny) × d, where d (nm) is the thickness of the layer (film). (3) Thickness Direction Retardation (Rth) "Rth(λ)" is the retardation in the thickness direction measured with light having a wavelength of λ nm at 23°C. For example, "Rth(550)" is the retardation in the thickness direction measured with light having a wavelength of 550 nm at 23°C. Rth(λ) is calculated by the formula: Rth(λ) = (nx - nz) x d, where d (nm) is the thickness of the layer (film). (4) Nz coefficient The Nz coefficient is calculated by Nz = Rth / Re. (5) Angle When an angle is mentioned in this specification, the angle includes both clockwise and counterclockwise angles relative to the reference direction. Therefore, for example, "45°" means ±45°.

[0010] A. Retardation Layer-Attached Polarizing Plate FIG. 1 is a schematic cross-sectional view showing the general configuration of a retardation layer-attached polarizing plate according to one embodiment of the present invention. The retardation layer-attached polarizing plate 100 includes a polarizer 11, a protective layer (viewing-side protective layer) 12 arranged on the viewing side of the polarizer 11, and a blocking layer 30 arranged on the opposite side of the polarizer 11 from the viewing side. The blocking layer 30 includes, in this order from the viewing side, a protective layer (inner protective layer) 13 of the polarizer 11 and a retardation layer 20. As described above, the protective layer 13 is arranged on the opposite side of the polarizer 11 from the viewing side, but the protective layer 13 may be omitted depending on the purpose, etc. Specifically, the blocking layer 30 does not need to include the protective layer 13. For example, if the retardation layer 20 is composed of a stretched resin film and can also serve as a protective layer for the polarizer, the protective layer 13 may be omitted. On the other hand, if the retardation layer 20 is an alignment-solidified layer of a liquid crystal compound, the protective layer 13 is typically arranged. The retardation layer 20 may be a single layer or may have a laminated structure in which two or more layers are laminated. 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 retardation layer-attached polarizing plate (thickness from the viewer-side protective layer to the retardation layer) is preferably 150 μm or less, more preferably 120 μm or less, even more preferably 100 μm or less, and particularly preferably 80 μm or less. The lower limit of the thickness of the retardation layer-attached polarizing plate is preferably 20 μm, more preferably 45 μm. Such a retardation layer-attached polarizing plate can have, for example, excellent flexibility and bending durability. As a result, the retardation layer-attached polarizing plate can be applied to an organic EL display device that can be curved, bent, folded, wound, etc.

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

[0013] Each member constituting the retardation layer-attached polarizing plate may 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 laminate structure of two or more layers, the respective retardation layers are bonded to each other via, for example, an adhesive layer (preferably using an active energy ray-curable adhesive). The blocking layer 30 may include an adhesive layer disposed between the polarizer 11 and the retardation layer 20.

[0014] Although not shown, in practice, a pressure-sensitive adhesive layer is provided on the side of the retardation layer 20 opposite to the side on which the polarizer 11 is disposed (specifically, as the outermost layer on the side opposite to the viewing side), so that the retardation layer-attached polarizing plate can be attached to the organic EL panel body. Furthermore, it is preferable that a release film (separator) is temporarily attached to the surface of the pressure-sensitive adhesive layer until the retardation layer-attached polarizing plate is used. Temporarily attaching the release film protects the pressure-sensitive adhesive layer and enables the retardation layer-attached polarizing plate to be formed into a roll.

[0015] The polarizing plate with a retardation layer may be in a long shape or a sheet shape. Here, "long" refers to an elongated shape in which the length is sufficiently longer than the width, for example, 10 times or more, preferably 20 times or more, the length than the width. A long polarizing plate with a retardation layer can be wound into a roll.

[0016] A-1. Blocking layer The blocking layer 30 has an ammonia gas permeability of 70 g / m ２ 24h or less, preferably 60g / m ２ 24 hours or less, more preferably 50 g / m ２ 24 hours or less, more preferably 40 g / m ２ 24 hours or less, particularly preferably 30 g / m ２ - 24 hours or less. By providing such a blocking layer, discoloration can be significantly suppressed. The inventors faced a new problem that a polarizing plate with a retardation layer discolors when applied to an organic EL display device. After extensive research into this problem, they discovered that the cause of discoloration is ammonia (essentially, ammonium ions) derived from the components that make up the organic EL panel. By using such a blocking layer 30, discoloration can be significantly suppressed by blocking as much ammonia as possible from reaching the polarizer 11. Specifically, decomposition of a dichroic substance (typically, an iodine complex) contained in the polarizer can be suppressed. The ammonia gas permeation amount of the blocking layer 30 is, for example, 3.0 g / m ２ ・24 hours or more.

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

[0018] The amount of ammonia gas that permeates can be determined by measuring the amount of permeation of an aqueous ammonia solution and the amount of permeation of water, and calculating the difference between these amounts.

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

[0020] From the viewpoint of achieving a thinner film, the thickness of the polarizer is, for example, preferably 15 μm or less, more preferably 12 μm or less, even more 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 even more preferably 3 μm or more. When the thickness of the polarizer is within this range, for example, curling during heating can be well suppressed, and good appearance durability during heating can be obtained.

[0021] The polarizer preferably exhibits absorptive dichroism at any wavelength between 380 nm and 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 even more preferably 44.5% or more. On the other hand, the single transmittance may be, for example, 46.0% or less, or 45.0% or less. The degree of polarization of the polarizer is preferably 97.0% or more, more preferably 99.0% or more, and even more preferably 99.9% or more.

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

[0023] A method for producing a polarizer from the above-mentioned 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. Examples of the resin film that can be used include hydrophilic polymer films such as polyvinyl alcohol (PVA)-based films, partially formalized PVA-based films, and partially saponified ethylene-vinyl acetate copolymer films. Because of their excellent optical properties, a polarizer is preferably obtained by dyeing a PVA-based film with iodine and uniaxially stretching it.

[0024] The dyeing with iodine is carried out, for example, by immersing the PVA-based film in an aqueous iodine solution. The stretching ratio of the uniaxial stretching is preferably 3 to 7 times. The stretching may be carried out after dyeing or while dyeing. Alternatively, the PVA-based film may be stretched and then dyed. If necessary, the PVA-based film may be subjected to a swelling treatment, a crosslinking treatment, a washing treatment, a drying treatment, or the like. For example, by immersing the PVA-based film in water and washing it before dyeing, it is possible to wash away dirt and antiblocking agents from the surface of the PVA-based film and also to swell the PVA-based film, thereby preventing uneven dyeing and the like.

[0025] Specific examples of polarizers obtained using the laminate include a laminate of a resin substrate and a PVA-based resin layer (PVA-based resin film) laminated on the resin substrate, or a laminate of a resin substrate and a PVA-based resin layer formed by coating on the resin substrate. A 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 the solution 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; and then stretching and dyeing the laminate to convert the PVA-based resin layer into a polarizer. In this embodiment, a polyvinyl alcohol-based resin layer containing a halide and a polyvinyl alcohol-based resin is preferably formed on one side of the resin substrate. The stretching typically involves immersing the laminate in an aqueous boric acid solution and stretching it. Furthermore, the stretching may further include, if necessary, in-air stretching of the laminate at an elevated temperature (e.g., 95°C or higher) before stretching in the aqueous boric acid solution. Additionally, in this embodiment, the laminate is preferably subjected to a drying shrinkage treatment in which the laminate is heated while being transported in the longitudinal direction, thereby shrinking the laminate by 2% or more in the width direction. Typically, the manufacturing method of this embodiment includes subjecting the laminate to an auxiliary in-air stretching treatment, a dyeing treatment, an underwater stretching treatment, and a drying shrinkage treatment, in this order. By introducing auxiliary stretching, it is possible to increase the crystallinity of the PVA, even when the PVA is coated on a thermoplastic resin, thereby achieving high optical properties. Furthermore, by simultaneously increasing the orientation of the PVA in advance, problems such as a decrease in the orientation or dissolution of the PVA when immersed in water in the subsequent dyeing or stretching steps can be prevented, thereby achieving high optical properties. Furthermore, when the PVA-based resin layer is immersed in a liquid, the disordering of the orientation of polyvinyl alcohol molecules and the decrease in the orientation can be suppressed compared to when the PVA-based resin layer does not contain a halide. This can improve the optical properties of a polarizer obtained through treatment steps in which the laminate is immersed in a liquid, such as a dyeing treatment and an underwater stretching treatment. Furthermore, the optical properties can be improved by shrinking the laminate in the width direction through drying shrinkage treatment.The obtained resin substrate / polarizer laminate may be used as is (i.e., the resin substrate may be used as a protective layer for the polarizer), or any suitable protective layer may be laminated depending on the purpose on the surface obtained by peeling the resin substrate from the resin substrate / polarizer laminate or on the surface opposite to the peeled surface. Details of the method for producing such a polarizer are described in, for example, JP 2012-73580 A and Japanese Patent No. 6,470,455 A. The entire disclosures of these publications are incorporated herein by reference.

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

[0027] The polarizing plate with a retardation layer 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 treatment such as hard coating treatment, anti-reflection treatment, anti-sticking treatment, and anti-glare treatment, as necessary.

[0028] The thickness of the viewer-side protective layer 12 can be appropriately set. The thickness of the viewer-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. Note that, if a surface treatment is applied, the thickness of the viewer-side protective layer 12 includes the thickness of the surface treatment layer.

[0029] In one embodiment, the ammonia gas permeation amount of the protective layer 13 is 70 g / m ２ 24h or less, preferably 60g / m ２ 24 hours or less, more preferably 50 g / m ２ 24 hours or less, more preferably 40 g / m ２ 24 hours or less, particularly preferably 30 g / m ２ In this case, the material constituting the protective layer 13 is preferably at least one selected from the group consisting of cellulose-based resins, cycloolefin-based resins, and polyester-based resins.

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

[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, it can typically function as a λ / 4 plate. Retardation layers are typically provided to impart anti-reflection properties to organic EL display devices. Retardation layers typically exhibit a refractive index 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. Note that "ny=nz" here encompasses not only cases where ny and nz are completely equal, but also cases where they are substantially equal. Therefore, there may be cases where ny>nz or ny<nz, as long as the effects of the present invention are not impaired.

[0033] 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 an excellent reflection hue can be obtained.

[0034] When the retardation layer is a single layer, the retardation layer preferably exhibits the inverse dispersion wavelength characteristic, in which the retardation value increases according to the wavelength of the measuring light.In this case, the 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 this configuration, it is possible to realize very excellent anti-reflection properties.

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

[0036] The retardation layer may be made of any appropriate material as long as it satisfies the above-mentioned characteristics. Specifically, the retardation layer may be a stretched resin film or a layer in which a liquid crystal compound is aligned and solidified (hereinafter referred to as a liquid crystal alignment and solidified layer).

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

[0038] When the retardation layer is a liquid crystal alignment solidified layer, the use of a liquid crystal compound can significantly increase the difference between nx and ny of the resulting retardation layer compared to non-liquid crystal materials, thereby significantly reducing the thickness of the retardation layer required to achieve the desired in-plane retardation. As a result, a polarizing plate with a retardation layer (and, consequently, an organic EL display device) can be made even thinner. In this specification, the term "alignment solidified layer" refers to a layer in which liquid crystal compounds are aligned in a predetermined direction within the layer and the alignment state is fixed. The term "alignment solidified layer" encompasses an alignment solidified layer obtained by curing a liquid crystal monomer. In this embodiment, typically, rod-shaped liquid crystal compounds are aligned in the slow axis direction of the retardation layer (homogeneous alignment). Specific examples of liquid crystal compounds and details of methods for forming a liquid crystal alignment solidified layer are described, for example, in JP-A-2006-163343 and JP-A-2006-178389. The disclosures of these publications are incorporated herein by reference.

[0039] The thickness of the retardation layer can be typically set to a thickness that allows it to function appropriately as a λ / 4 plate. When the retardation layer is a stretched 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 solidified 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 consisting 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, we describe a 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, but these may also be reversed. The thickness of the first liquid crystal alignment solidified layer can be adjusted to obtain the 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 to obtain the 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 even more preferably 250 nm to 280 nm. The in-plane retardation Re(550) of the second liquid crystal alignment solidified layer, as described above, is preferably 100 nm to 190 nm, more preferably 110 nm to 170 nm, and even more preferably 120 nm to 160 nm. The angle between 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 even more preferably about 15°. The angle between 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 even more preferably about 75°. With this configuration, it is possible to obtain characteristics close to ideal reverse wavelength dispersion characteristics, and as a result, it is possible to realize extremely excellent antireflection characteristics.

[0041] In one embodiment, the ammonia gas permeation amount of the retardation layer 20 is 70 g / m ２ 24h or less, preferably 60g / m ２ 24 hours or less, more preferably 50 g / m ２ 24 hours or less, more preferably 40 g / m ２ 24 hours or less, particularly preferably 30 g / m ２- 24 hours or less. In this case, a stretched film of the above-mentioned resin film is preferably used as the retardation layer 20. It is preferable to use at least one selected from a cycloolefin resin and a polyester resin as a constituent material of the protective layer 13 to be combined with the retardation layer 20, which is a stretched film of the resin film. With such a combination, discoloration can be significantly suppressed.

[0042] It is preferable to use a cellulose-based resin as a constituent material of the protective layer 13 to be combined with the retardation layer 20, which is a liquid crystal alignment solidified layer. With such a combination, discoloration can be significantly suppressed.

[0043] B. Organic EL Display Device The retardation layer-attached polarizing plate can be applied to an organic EL display device. Accordingly, an organic EL display device according to an embodiment of the present invention includes the retardation layer-attached polarizing plate.

[0044] FIG. 2 is a schematic cross-sectional view illustrating an organic EL panel and a polarizing plate with a retardation layer disposed thereon in an organic EL display device according to one embodiment of the present invention. The retardation layer-attached polarizing plate 100 is disposed such that its blocking layer 30 is closer to the organic EL panel body 40 than the polarizer 11. Specifically, the retardation layer-attached polarizing plate 100 is attached to the organic EL panel body 40 via an adhesive layer (not shown). The organic EL panel body 40 includes a substrate 60 and an upper structure layer 80 including a circuit layer including thin-film transistors (TFTs) and the like, an organic light-emitting diode (OLED), and a sealing film for sealing the OLED. The upper structure layer 80 includes, for example, a nitrogen-containing layer (e.g., a nitride layer), which may generate ammonia (ammonia ions). The retardation layer-attached polarizing plate can significantly suppress discoloration in an organic EL display device. Furthermore, the discoloration problem can be solved without changing the design of the organic EL panel body.

[0045] For example, when a flexible substrate (for example, a resin substrate) is used as the substrate 60, the resulting organic EL display device can be curved, bent, folded, rolled up, and the like.

[0046] The present invention will be described in detail below using examples, but the present invention is not limited to 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: Thicknesses of 10 μm or less were measured using an interference film thickness meter (manufactured by Otsuka Electronics Co., Ltd., product name "MCPD-3000"). Thicknesses exceeding 10 μm were measured using a digital micrometer (manufactured by Anritsu Corporation, product name "KC-351C"). (2) Ammonia Gas Permeability: 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. These were then sealed with a test piece (film) cut into a circle with a diameter of 6 cm. In this state, cups A and B were placed in an oven (atmospheric pressure) set at 40°C for 24 hours, and the weight changes of cups A and B before and after placement were measured. The difference between the weight change of cup A (amount of ammonia gas and water permeated) and the weight change of cup B (amount of water permeated) was calculated, and the amount of ammonia gas permeated (g / m ２ ・24h) was calculated.

[0047] Example 1 1. Preparation of Polarizer A long, amorphous, isophthalic copolymerized polyethylene terephthalate film (thickness: 100 μm) with a water absorption rate of 0.75% and a Tg of approximately 75°C was used as the thermoplastic resin substrate. One side of the resin substrate was subjected to a corona treatment. A PVA-based resin (a 9:1 mixture of polyvinyl alcohol (degree of polymerization: 4200, degree of saponification: 99.2 mol%) and acetoacetyl-modified PVA (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name "GOHSEFIRMER Z410") was prepared by mixing 100 parts by weight of the resin with 13 parts by weight of potassium iodide, and the resulting solution was dissolved in water to prepare an aqueous PVA solution (coating solution). The PVA aqueous solution was applied to the corona-treated surface of the resin substrate and dried at 60°C to form a 13 μm-thick PVA-based resin layer, producing a laminate. The resulting laminate was free-end uniaxially stretched 2.4 times in the longitudinal direction (machine direction) between rolls with different peripheral speeds in an oven at 130°C (in-air auxiliary stretching treatment). The laminate was then immersed in an insolubilizing bath (a boric acid aqueous solution obtained by blending 4 parts by weight of boric acid with 100 parts by weight of water) at a liquid temperature of 40°C for 30 seconds (insolubilization treatment). The laminate was then immersed in a dyeing bath (an iodine aqueous solution obtained by blending iodine and potassium iodide in a weight ratio of 1:7 with 100 parts by weight of water) at a liquid temperature of 30°C for 60 seconds while adjusting the concentration so that the final polarizing film had a single transmittance (Ts) of 43.0% (dyeing treatment). The laminate was then immersed in a crosslinking bath (a boric acid aqueous solution obtained by blending 3 parts by weight of potassium iodide and 5 parts by weight of boric acid with 100 parts by weight of water) at a liquid temperature of 40°C for 30 seconds (crosslinking treatment). The laminate was then immersed in a boric acid aqueous solution (boric acid concentration 4.0 wt %, potassium iodide 5.0 wt %) at a liquid temperature of 70°C and uniaxially stretched in the longitudinal direction (longitudinal direction) between rolls operating at different peripheral speeds to a total stretch ratio of 5.5 (underwater stretching treatment). The laminate was then immersed in a cleaning bath (aqueous solution obtained by blending 4 parts by weight of potassium iodide with 100 parts by weight of water) at a liquid temperature of 20°C (washing treatment). The laminate was then dried in an oven maintained at 90°C and brought into contact with a SUS heated roll maintained at a surface temperature of 75°C for approximately 2 seconds (drying shrinkage treatment). The shrinkage rate of the laminate in the width direction due to the drying shrinkage treatment was 5.2%. In this manner, a polarizer having a thickness of 5 μm was formed on the resin substrate.

[0048] 2. Preparation of Polarizing Plate A 25 μm thick TAC film was bonded to the polarizer surface of the resin substrate / polarizer laminate obtained above via a UV-curable adhesive. Specifically, the curable adhesive was applied to a thickness of 1.0 μm, and the films were bonded using a rolling mill. Thereafter, UV light was irradiated from the TAC film side to cure the adhesive. Next, the resin substrate was peeled from the polarizer, and a cycloolefin resin film (thickness 13 μm, ammonia gas permeability 54 g / m) was applied to the peeled surface. ２ 24h: A ​​COP film (hereinafter referred to as a COP film) was attached to the TAC film in the same manner as above. In this manner, a polarizing plate having a TAC film / polarizer / COP film structure was obtained.

[0049] 3. Preparation of Retardation Film Constituting Retardation Layer 3-1. Polymerization of Polyester Carbonate Resin Polymerization was carried out using a batch polymerization apparatus consisting of two vertical reactors equipped with a stirring blade and a reflux condenser controlled at 100°C. Bis[9-(2-phenoxycarbonylethyl)fluoren-9-yl]methane 29.60 parts by mass (0.046 mol), isosorbide (ISB) 29.21 parts by mass (0.200 mol), spiroglycol (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 × 10 as a catalyst. －２ Parts by mass (6.78×10 －５mol) was charged. After purging the reactor with nitrogen under reduced pressure, heating was performed with a heat medium, and stirring was initiated when the internal temperature reached 100°C. 40 minutes after the start of the temperature increase, the internal temperature reached 220°C, and while controlling to maintain this temperature, pressure reduction was initiated. 90 minutes after reaching 220°C, the pressure was reduced to 13.3 kPa. Phenol vapor by-produced during the polymerization reaction was introduced into a reflux condenser at 100°C, and a small amount of monomer components contained in the phenol vapor were returned to the reactor, while uncondensed phenol vapor was introduced into a condenser at 45°C and recovered. Nitrogen was introduced into the first reactor, and the pressure was temporarily restored to atmospheric pressure. The oligomerized reaction liquid in the first reactor was then transferred to the second reactor. Next, heating and pressure reduction in the second reactor were initiated, and the internal temperature reached 240°C and the pressure reached 0.2 kPa in 50 minutes. Polymerization was then allowed to proceed until the predetermined stirring power was achieved. When the predetermined power was reached, nitrogen was introduced into the reactor to restore pressure, and the polyester carbonate resin produced was extruded into water, and the strands were cut to obtain pellets.

[0050] 3-2. Preparation of Retardation Film The obtained polyester carbonate resin (pellets) was vacuum-dried at 80 ° C. for 5 hours, and then a film-forming device equipped with a single-screw extruder (manufactured by Toshiba Machine Co., Ltd., cylinder setting temperature: 250 ° C.), a T-die (width 200 mm, setting temperature: 250 ° C.), a chill roll (setting temperature: 120 to 130 ° C.) and a winder was used to produce a long resin film having 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 having a thickness of 47 μm. The Re (550) of the obtained retardation film was 141 nm, Re (450) / Re (550) was 0.82, and the Nz coefficient was 1.12. The ammonia gas permeation amount of the obtained retardation film was 10 g / m ２ ・It was 24 hours.

[0051] 4. Preparation of Pressure-Sensitive Adhesive 4-1. Preparation of Acrylic Polymer A monomer mixture containing 91 parts of butyl acrylate, 6 parts of acryloylmorpholine (ACMO), 2.7 parts of acrylic acid, and 0.3 parts of 4-hydroxybutyl acrylate was charged into a four-neck flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser. Furthermore, 0.1 parts of 2,2'-azobisisobutyronitrile as a polymerization initiator was charged together with 100 parts of ethyl acetate to 100 parts of this monomer mixture. Nitrogen gas was introduced with gentle stirring to replace the atmosphere, and the liquid temperature in the flask was maintained at around 55°C while a polymerization reaction was carried out for 8 hours to prepare an acrylic polymer solution.

[0052] 4-2. Preparation of Pressure-Sensitive Adhesive A pressure-sensitive adhesive was obtained by blending 0.1 parts of a trimethylolpropane / tolylene diisocyanate adduct (manufactured by Tosoh Corporation, trade name "Coronate L"), 0.3 parts of a peroxide crosslinking agent (benzoyl peroxide), and 0.2 parts of an epoxy group-containing silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "KBM-403") with 100 parts of the solid content of the obtained acrylic polymer solution. The ammonia gas permeability of the obtained pressure-sensitive adhesive (thickness 20 μm) was 118 g / m. ２ ・It was 24 hours.

[0053] 5. Preparation of a polarizing plate with a retardation layer The retardation film obtained in 3 above was attached to the COP film surface of the polarizing plate obtained in 2 above via the adhesive (thickness 20 μm) obtained in 4 above. At this time, the polarizer was attached 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 a polarizing plate, a PET film (thickness: 30 μm, ammonia gas permeability: 53 g / m) was used instead of a COP film. ２ A polarizing plate with a retardation layer was obtained in the same manner as in Example 1 except that the film thickness was 24 h.

[0055] [Example 3] In the production of a polarizing plate, a TAC film (thickness: 25 μm, ammonia gas permeability: 30 g / m) was used instead of a COP film. ２A polarizing plate with a retardation layer was obtained in the same manner as in Example 1 except that the film thickness was 24 h.

[0056] [Example 4] In the production of a polarizing plate, an acrylic film having a lactone ring structure (thickness: 20 μm, ammonia gas permeability: 78 g / m) was used instead of a COP film. ２ A polarizing plate with a retardation layer was obtained in the same manner as in Example 1 except that the film thickness was 24 h.

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

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

[0059] (Preparation of Liquid Crystal Alignment Solidified Layer Constituting Retardation Layer) 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 400 parts of cyclopentanone (CPN), heated to 60 ° C., stirred to dissolve, and after dissolution was confirmed, the mixture was returned to room temperature, and 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 stirred to obtain a solution. The solution was transparent and uniform. The obtained solution was filtered through a 0.20 μm membrane filter to obtain a polymerizable composition. Meanwhile, a polyimide solution for an alignment film was applied to a 0.7 mm thick glass substrate using a spin coating method, dried at 100 ° C. for 10 minutes, and then baked 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 carried out using a commercially available rubbing device. The polymerizable composition obtained above was applied to a substrate (substantially an alignment film) by spin coating, and dried at 100°C for 2 minutes. After the obtained coating film was cooled to room temperature, it was irradiated with 30 mW / cm using a high-pressure mercury lamp. ２The liquid crystal alignment layer was then irradiated with ultraviolet light at an intensity of 100 nm for 30 seconds to obtain a liquid crystal alignment layer. The in-plane retardation Re(550) of the obtained liquid crystal alignment layer was 130 nm, Re(450) / Re(550) was 0.851, and the liquid crystal alignment layer exhibited reverse dispersion wavelength characteristics. The ammonia gas permeability of the obtained liquid crystal alignment layer was 103 g / m ２ ・It was 24 hours.

[0060]

[0061] [Example 7] In the production of a polarizing plate, a TAC film (thickness: 25 μm, ammonia gas permeability: 30 g / m) was used instead of a COP film. ２ A polarizing plate with a retardation layer was obtained in the same manner as in Example 1, except that a liquid crystal alignment solidified layer was used as the retardation layer, and that an ultraviolet-curable adhesive (thickness: 1.0 μm) was used instead of the pressure-sensitive adhesive when bonding to the polarizing plate.

[0062] [Comparative Example 1] In the production of a polarizing plate, a 40 μm thick TAC film was used instead of a 25 μm thick TAC film, and an acrylic film having a lactone ring structure (thickness: 20 μm, ammonia gas permeability: 78 g / m) was used instead of a COP film. ２ A polarizing plate with a retardation layer was obtained in the same manner as in Example 1, except that the liquid crystal alignment solidified layer was used as the retardation layer.

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

[0064] [Comparative Example 3] In the production of a polarizing plate, an acrylic film (thickness: 20 μm) having a lactone ring structure was used instead of a 25 μm-thick TAC film, and an acrylic film (thickness: 20 μm, ammonia gas permeability: 78 g / m) having a lactone ring structure was used instead of a COP film. ２A polarizing plate with a retardation layer was obtained in the same manner as in Example 1, except that the liquid crystal alignment solidified layer was used as the retardation layer.

[0065] The following evaluations were carried out for 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> ○ Single transmittance and degree of polarization For the polarizing plates of the Examples and Comparative Examples, the single transmittance Ts, parallel transmittance Tp, and crossed transmittance Tc were measured using an ultraviolet-visible spectrophotometer (LPF-2000 manufactured by Otsuka Electronics Co., Ltd.), and were taken as Ts, Tp, and Tc of the polarizer, respectively. These Ts, Tp, and Tc are Y values ​​measured using a 2-degree visual field (C light source) according to JIS Z8701 and corrected for visibility. From the obtained Tp and Tc, the degree of polarization P was calculated using the following formula: Degree of polarization P (%) = {(Tp - Tc) / (Tp + Tc)} １／２ ×100 ○ Ammonia Bleaching Test 10 g of a 10% aqueous ammonia solution was placed in a glass bottle (cylindrical, 30 mm in diameter, 50 mm deep), and the opening of the glass bottle was covered with the retardation layer-attached polarizing plate obtained in the Examples and Comparative Examples (with the retardation layer in contact with the opening) to seal the bottle. In this state, the glass bottle was heated at 65°C for 2 hours. After heating, the degree of polarization was measured at a location corresponding to the opening of the glass bottle, and ΔP was calculated using the following formula, where P is the degree of polarization of the retardation layer-attached polarizing plate (essentially a polarizer) before heating and P' is the degree of polarization after heating. A smaller ΔP means that bleaching by ammonia is more suppressed. ΔP=P-P'

[0066]

[0067] In the examples, ΔP was less than 20%, and a polarizing plate with a retardation layer was obtained in which the polarization degree hardly changed (no bleaching occurred) even when exposed to ammonia. On the other hand, in the comparative examples, the polarization degree was significantly reduced, and some of the polarizing function was almost completely lost.

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

[0069] REFERENCE SIGNS LIST 10 Polarizing plate 11 Polarizer 12 Protective layer (viewing-side protective layer) 13 Protective layer (inner protective layer) 20 Retardation layer 30 Blocking layer 100 Polarizing plate with retardation layer

Claims

1. A polarizer; and a blocking layer that is disposed on one side of the polarizer and includes a retardation layer, wherein the blocking layer has an ammonia gas permeability of 70 g / m ２ A polarizing plate with a retardation layer, the retardation layer having a retardation time of 24 hours or less.

2. The retardation layer has an ammonia gas permeability of 70 g / m ２ The polarizing plate with a retardation layer according to claim 1, wherein the retardation period is 24 hours or less.

3. The polarizing plate with a retardation layer according to claim 1 or 2, wherein the blocking layer includes a protective layer for the polarizer.

4. The ammonia gas permeability of the protective layer is 70 g / m ２ The polarizing plate with a retardation layer according to claim 3, wherein the retardation period is 24 hours or less.

5. The polarizing plate with a retardation layer according to any one of claims 1 to 4, further comprising a protective layer disposed on the other side of the polarizer.

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

7. The polarizing plate with a retardation layer according to claim 1, wherein Re(450) / Re(550) of the retardation layer is 0.8 or more and less than 1.

8. The polarizing plate with a retardation layer according to any one of claims 1 to 7, wherein the polarizer has a thickness of 10 µm or less.

9. The polarizing plate with a retardation layer according to any one of claims 1 to 8, which has a thickness of 150 µm or less.

10. An organic electroluminescence display device comprising the retardation layer-attached polarizing plate according to any one of claims 1 to 9.

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