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

Abstract

To provide a thin polarizing plate with a phase difference layer that can suppress metal corrosion. [Solution] The polarizing plate with a phase difference layer according to an embodiment of the present invention comprises a polarizing plate including a polarizing film containing iodine and having a first main surface and a second main surface facing each other, an adhesive layer disposed on the second main surface side of the polarizing film, a phase difference layer disposed between the polarizing film and the adhesive layer, and an inorganic film containing silicon disposed between the polarizing film and the adhesive layer, wherein the thickness of the laminated portion from the polarizing plate to the layer adjacent to the adhesive layer is 50 μm or less.

Description

[Technical Field]

[0001] The present invention relates to a polarizing plate with a phase difference layer and an image display device using the same. [Background technology]

[0002] Image display devices, such as liquid crystal displays and electroluminescent (EL) displays (e.g., organic EL displays and inorganic EL displays), are rapidly becoming widespread. Typically, polarizers and phase difference plates are used in image display devices. In practical terms, polarizers with an integrated phase difference layer are widely used (e.g., Patent Document 1).

[0003] In recent years, with the growing demand for thinner image display devices, there has also been a strong demand for thinner polarizing plates with phase difference layers. For example, the possibility of bending, flexing, folding, and winding image display devices using flexible substrates (e.g., resin substrates) has been explored, and there is a need for thin polarizing plates with phase difference layers that can accommodate these processes. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Patent No. 3325560 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] Thinning of polarizing plates with phase difference layers can be achieved, for example, by omitting or thinning the protective layer of the polarizing film included in the polarizing plate, or by thinning the phase difference layer (phase difference film). However, if thin polarizing plates with phase difference layers are used in image display devices, the metal parts of the image display device (e.g., electrodes, wiring) may corrode. Such metal corrosion is particularly pronounced in high-temperature, high-humidity environments.

[0006] The present invention has been made in view of the above, and its main objective is to provide a thin polarizing plate with a phase difference layer that can suppress metal corrosion. [Means for solving the problem]

[0007] A polarizing plate with a phase difference layer according to an embodiment of the present invention comprises a polarizing plate containing a polarizing film having a first main surface and a second main surface facing each other and containing iodine; an adhesive layer disposed on the second main surface side of the polarizing film; a phase difference layer disposed between the polarizing film and the adhesive layer; and an inorganic film containing silicon disposed between the polarizing film and the adhesive layer, wherein the thickness of the laminated portion from the polarizing plate to the layer adjacent to the adhesive layer is 50 μm or less. In one embodiment, the polarizing film, the phase difference layer, and the inorganic film are arranged in this order. In one embodiment, the inorganic film is disposed in direct contact with the phase difference layer. In one embodiment, the thickness of the inorganic film is less than 400 nm. In one embodiment, the thickness of the inorganic film is 50 nm or more. In one embodiment, the inorganic film comprises at least one selected from the group consisting of silicon dioxide, silicon carbide, and composites thereof. In one embodiment, the inorganic film is a vapor-deposited film. In one embodiment, the moisture permeability of the laminated portion of the polarizing film from the layer adjacent to the second main surface to the layer adjacent to the adhesive layer at 40°C and 92% RH is 50 g / m². 2 • Less than 24 hours In one embodiment, the phase difference layer is an orientation-solidified layer of a liquid crystal compound. According to another aspect of the present invention, an image display device is provided. This image display device has the above-described polarizing plate with a phase difference layer. [Effects of the Invention]

[0008] According to the polarizing plate with a phase difference layer in the embodiment of the present invention, metal corrosion can be suppressed.

Brief Description of the Drawings

[0009] [Figure 1] It 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. [Figure 2] In an organic EL display device according to one embodiment of the present invention, it is a schematic cross-sectional view showing a schematic state in which a polarizing plate with a retardation layer is arranged on an organic EL panel.

Embodiments for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to these embodiments. For the sake of clearer explanation, in the drawings, the widths, thicknesses, shapes, etc. of each part may be schematically represented compared to the embodiments, but this is merely an example and does not limit the interpretation of the present invention. Also, for the drawings, the same or equivalent elements may be denoted by the same reference numerals, and duplicate explanations may be omitted.

[0011] (Definitions 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 in which 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 Retardation (Re) "Re(λ)" is the in-plane retardation measured with light of wavelength λ nm at 23°C. For example, "Re(550)" is the in-plane retardation measured with light of wavelength 550 nm at 23°C. Re(λ) is obtained by the formula: Re(λ) = (nx - ny) × d when the thickness of the layer (film) is d (nm). (3) Retardation in the Thickness Direction (Rth) "Rth(λ)" is the retardation in the thickness direction measured with light of wavelength λ nm at 23°C. For example, "Rth(550)" is the retardation in the thickness direction measured with light of wavelength 550 nm at 23°C. Rth(λ) can be 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°.

[0012] FIG. 1 is a schematic cross-sectional view showing the 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 includes a polarizing film 11 having first and second main surfaces 11a and 11b facing each other, a protective layer 12 disposed on the first main surface 11a side of the polarizing film 11, and a retardation layer 20, an inorganic film 30, and an adhesive layer 40 disposed on the second main surface 11b side of the polarizing film 11. No protective layer is disposed between the polarizing film 11 and the retardation layer 20, and the retardation layer 20 is disposed adjacent to the polarizing film 11 and can function as a protective layer for the polarizing film 11. According to such a configuration, the thickness of the polarizing plate with a retardation layer described below can be achieved favorably. The polarizing plate 100 with a retardation layer is typically disposed such that the polarizing film 11 is on the viewing side rather than the retardation layer 20 in an image display device. In one embodiment, the protective layer 12 is located on the outermost surface of the image display device. The polarizing plate 100 with a retardation layer can be obtained, for example, by laminating a polarizing plate 10 obtained by laminating the polarizing film 11 and the protective layer 12, and other layers.

[0013] In the illustrated example, the polarizing plate 10 includes the polarizing film 11 and the protective layer 12 disposed on the first main surface 11a side of the polarizing film 11, but the protective layer 12 may be omitted. Also, although the retardation layer 20 has a laminated structure including a first retardation layer 21 and a second retardation layer 22, different from the illustrated example, the retardation layer 20 may have a laminated structure of three or more layers or may be a single layer.

[0014] Each component constituting the polarizing plate with a phase difference layer can be laminated via any suitable adhesive layer (not shown). Specific examples of adhesive layers include adhesive layers and tack layers. For example, the protective layer 12 is bonded to the polarizing film 11 via an adhesive layer (preferably using an active energy ray curable adhesive). For example, the phase difference layer 20 is bonded to the polarizing film 11 via an adhesive layer (preferably using an active energy ray curable adhesive). As shown in the figure, if the phase difference layer 20 has a laminated structure of two or more layers, the phase difference layers are bonded to each other, for example, via an adhesive layer (preferably using an active energy ray curable adhesive). The thickness of the adhesive layer is preferably 0.4 μm or more, more preferably 0.4 μm to 3.0 μm, and even more preferably 0.6 μm to 2.2 μm.

[0015] The adhesive layer 40, positioned on the second main surface 11b side of the polarizing film 11, allows the polarizing plate 100 with a phase difference layer to be attached to an image display panel included in an image display device. Although not shown, a release liner is practically bonded to the surface of the adhesive layer 40. The release liner can be temporarily attached until the polarizing plate with a phase difference layer is put into use. By using the release liner, for example, the adhesive layer is protected and roll formation of the polarizing plate with a phase difference layer is possible.

[0016] An inorganic film 30 is placed between the polarizing film 11 and the adhesive layer 40. By using the inorganic film 30, corrosion of the metal can be suppressed while contributing to the thinning of the polarizing plate with a phase difference layer. The arrangement of the inorganic film 30 is not particularly limited, but from the viewpoint of preventing cosmetic defects (e.g., the occurrence of cracks), it is preferable that the inorganic film 30 be placed on the side of the phase difference layer 20 where the polarizing film 11 is not placed, as shown in the figure. The inorganic film 30 is placed, for example, in direct contact with the phase difference layer 20. With such a configuration, it is possible to contribute to the thinning of the polarizing plate with a phase difference layer.

[0017] A polarizing plate with a phase difference layer may be elongated or in sheet form. Here, "elongated" refers to a slender shape in which the length is sufficiently longer than the width, for example, a slender shape in which the length is 10 times or more, preferably 20 times or more, than the width. An elongated polarizing plate with a phase difference layer can be wound into a roll.

[0018] The thickness of the laminated portion from the polarizing plate 10 (protective layer 12) to the layer adjacent to the adhesive layer 40 (inorganic film 30 in the illustrated example) (sometimes simply referred to as "thickness of the polarizing plate with phase difference layer") is, for example, 60 μm or less, preferably 50 μm or less, and more preferably 40 μm or less. Such a thickness contributes to the thinning of the image display device and, for example, makes it possible to mount components (such as batteries) to accommodate larger screens. It can also be well adapted to deformable image display devices such as those that can be curved, bent, folded, or rolled up. On the other hand, the thickness of the polarizing plate with phase difference layer is, for example, 10 μm or more.

[0019] The thickness of the polarizing plate with a phase difference layer mentioned above includes the thickness of the adhesive layer. For example, it includes the thickness of an adhesive layer that may be placed between the protective layer and the polarizing film, an adhesive layer that may be placed between the polarizing film and the phase difference layer, and an adhesive layer that may be placed between phase difference layers if the phase difference layer has a laminated structure. However, the thickness of the polarizing plate with a phase difference layer does not include the thickness of the adhesive layer used to adhere the polarizing plate with a phase difference layer to an external substrate such as a panel or glass.

[0020] The moisture permeability of the laminated portion from the layer adjacent to the second main surface 11b of the polarizing film 11 to the layer adjacent to the adhesive layer 40 at 40°C and 92% RH is preferably 200 g / m². 2 • Less than 24 hours, more preferably 150 g / m² 2 • Less than 24 hours, and more preferably 100 g / m² 2 • Less than 24 hours, and particularly preferably 50 g / m² 2• Less than 24 hours. With this configuration, metal corrosion can be suppressed more effectively. Specifically, the elution and migration of iodine from the polarizing film can be suppressed. On the other hand, the moisture permeability of the laminated portion from the layer adjacent to the second main surface of the polarizing film to the layer adjacent to the adhesive layer at 40°C and 92% RH is, for example, 1 g / m². 2 • The time between installations must be 24 hours or longer. Note that "adjacent" includes not only directly adjacent installations but also those adjacent via an adhesive layer.

[0021] A. Polarizing plate The above polarizing plate includes a polarizing film and a protective layer. Typically, a polarizing plate can be obtained by laminating a polarizing film and a protective layer with an adhesive layer in between.

[0022] A-1. Polarizing film The polarizing film described above is typically a resin film containing a dichroic substance. Iodine is preferably used as the dichroic substance. Examples of resin films include hydrophilic polymer films such as polyvinyl alcohol (PVA) films, partially formalized PVA films, and partially saponified ethylene-vinyl acetate copolymer films.

[0023] The thickness of the polarizing film is preferably 12 μm or less, more preferably 10 μm or less, and even more preferably 8 μm or less. On the other hand, the thickness of the polarizing film is preferably 1 μm or more.

[0024] The polarizing film preferably exhibits absorption dichroism at any wavelength between 380 nm and 780 nm. The transmittance of the polarizing film alone is, for example, 41.5% to 48.0%, preferably 42.0% to 46.0%. The degree of polarization of the polarizing film is, for example, 90.0% or higher, preferably 99.0% or higher, and more preferably 99.9% or higher.

[0025] Polarizing films can be fabricated by any suitable method. Specifically, polarizing films may be made from a single layer of resin film, or from a laminate of two or more layers.

[0026] The method for producing a polarizing film from the above-mentioned single-layer resin film typically involves dyeing the resin film with a dichroic substance such as iodine or a dichroic dye, and then stretching it. Examples of hydrophilic polymer films used as the resin film include polyvinyl alcohol (PVA) films, partially formalized PVA films, and partially saponified ethylene-vinyl acetate copolymer films. This method may further include insolubilization treatment, swelling treatment, crosslinking treatment, etc. Since such manufacturing methods are well-known and commonly used in this industry, a detailed explanation is omitted.

[0027] A polarizing film obtained using the above laminate can be made, for example, using a laminate of a resin substrate and a resin film or resin layer (typically a PVA-based resin layer). Specifically, it can be made by applying a PVA-based resin solution to a resin substrate, drying it to form a PVA-based resin layer on the resin substrate, and obtaining a laminate of a resin substrate and a PVA-based resin layer; and stretching and dyeing the laminate to make the PVA-based resin layer a polarizing film. In this embodiment, preferably, a PVA-based resin layer containing a halide and a PVA-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. Furthermore, stretching may further include, if necessary, air-stretching the laminate at a high temperature (e.g., 95°C or higher) before stretching in the aqueous boric acid solution. In addition, in this embodiment, preferably, the laminate is subjected to a drying shrinkage treatment in which it shrinks by 2% or more in the width direction by heating while being transported in the longitudinal direction. Typically, the manufacturing method of this embodiment involves subjecting the laminate to an air-assisted stretching treatment, a dyeing treatment, a water-assisted stretching treatment, and a drying shrinkage treatment in that order. By introducing auxiliary stretching, it is possible to increase the crystallinity of PVA even when PVA is coated on a thermoplastic resin, thereby achieving high optical properties. At the same time, by increasing the orientation of PVA in advance, problems such as a decrease in the orientation of PVA and dissolution can be prevented when immersed in water during the subsequent dyeing and stretching processes, thereby achieving high optical properties. Furthermore, when the PVA-based resin layer is immersed in a liquid, the disorder of the orientation of PVA molecules and the decrease in orientation can be suppressed compared to when the PVA-based resin layer does not contain halides, thereby achieving high optical properties. Furthermore, by shrinking the laminate in the width direction through the drying shrinkage treatment, high optical properties can be achieved. A polarizing plate can be obtained by laminating a protective layer on the peeled surface obtained by peeling the resin substrate from the obtained resin substrate / polarizing film laminate, or on the surface opposite to the peeled surface. Details of the method for manufacturing such polarizing films are described, for example, in Japanese Patent Publication No. 2012-73580 and Japanese Patent No. 6470455. The entire contents of these publications are incorporated herein by reference.

[0028] A-2.Protective layer The protective layer described above can be formed from any suitable film that can be used as a protective layer for a polarizing film. Specific examples of materials that make up the main component of the film include cellulosic resins such as triacetylcellulose (TAC), polyester, polyvinyl alcohol, polycarbonate, polyamide, polyimide, polyethersulfone, polysulfone, polystyrene, cycloolefins such as polynorbornene, polyolefins, (meth)acrylic, and acetate resins.

[0029] In the polarizing plate with a phase difference layer according to the embodiment of the present invention, the polarizing plate is typically placed on the viewing side of an image display device, and the protective layer is also placed on the viewing side. Therefore, the protective layer may be subjected to surface treatments such as hard coat (HC) treatment, anti-reflective treatment, anti-sticking treatment, and anti-glare treatment as needed.

[0030] The thickness of the protective layer is preferably less than 30 μm, and more preferably 28 μm or less. On the other hand, the thickness of the protective layer is preferably 11 μm or more, and more preferably 13 μm or more. If the above surface treatment is applied, the thickness of the protective layer includes the thickness of the surface treatment layer.

[0031] B. Retardation layer The thickness of the phase difference layer, depending on its configuration (whether it is a single layer or has a laminated structure), is preferably 10 μm or less, more preferably 8 μm or less, and even more preferably 7 μm or less. On the other hand, the thickness of the phase difference layer is, for example, 0.5 μm or more. Note that if the phase difference layer has a laminated structure, "thickness of the phase difference layer" means the sum of the thicknesses of each phase difference layer. Specifically, "thickness of the phase difference layer" does not include the thickness of the adhesive layer.

[0032] Preferably, an orientation-solidified layer of liquid crystal compounds (liquid crystal orientation-solidified layer) is used as the phase difference layer. By using a liquid crystal compound, for example, the difference between nx and ny in the resulting phase difference layer can be made significantly larger compared to non-liquid crystal materials, so the thickness of the phase difference layer required to obtain the desired in-plane phase difference can be significantly reduced. Therefore, a remarkable reduction in the thinness of the polarizing plate with a phase difference layer can be achieved. In this specification, "orientation-solidified layer" refers to a layer in which liquid crystal compounds are oriented in a predetermined direction within the layer, and this orientation state is fixed. Note that "orientation-solidified layer" is a concept that includes orientation-hardened layers obtained by hardening liquid crystal monomers as described later. In the phase difference layer, typically, rod-shaped liquid crystal compounds are oriented in a state where they are aligned along the slow phase axis direction of the phase difference layer (homogenous orientation).

[0033] The above-mentioned liquid crystal alignment solidification layer can be formed by applying an alignment treatment to the surface of a predetermined substrate, coating the surface with a coating liquid containing a liquid crystal compound to orient the liquid crystal compound in a direction corresponding to the alignment treatment, and fixing the alignment state. Any appropriate alignment treatment can be used as the alignment treatment. Specifically, these include mechanical alignment treatment, physical alignment treatment, and chemical alignment treatment. Specific examples of mechanical alignment treatment include rubbing treatment and stretching treatment. Specific examples of physical alignment treatment include magnetic field alignment treatment and electric field alignment treatment. Specific examples of chemical alignment treatment include oblique deposition and photo-alignment treatment. Any appropriate treatment conditions can be adopted for each type of alignment treatment depending on the purpose.

[0034] The orientation of liquid crystal compounds is achieved by treating them at a temperature that exhibits the liquid crystal phase, depending on the type of liquid crystal compound. This temperature treatment causes the liquid crystal compound to enter a liquid crystal state, and it then orients according to the orientation treatment direction on the substrate surface.

[0035] In one embodiment, the orientation state is fixed by cooling the liquid crystal compound oriented as described above. If the liquid crystal compound is a polymerizable monomer or a crosslinkable monomer, the orientation state is fixed by subjecting the liquid crystal compound oriented as described above to a polymerization treatment or a crosslinking treatment.

[0036] Specific examples of liquid crystal compounds and details of the method for forming the orientation solidified layer are described in Japanese Patent Publication No. 2006-163343. The description in said publication is incorporated herein by reference.

[0037] As described above, the phase difference layer may be a single layer or may have a laminated structure of two or more layers.

[0038] Unlike the illustrated example, when the phase difference layer is a single layer, the phase difference layer can function as a λ / 4 plate. Specifically, the Re(550) of the phase difference layer is preferably 100 nm to 180 nm, more preferably 110 nm to 170 nm, and even more preferably 110 nm to 160 nm. The thickness of the phase difference layer can be adjusted to obtain the desired in-plane phase difference of the λ / 4 plate. When the phase difference layer is the liquid crystal alignment solidification layer described above, its thickness is, for example, 1.0 μm to 2.5 μm. In this embodiment, the angle between the slow axis of the phase difference layer and the absorption axis of the polarizing film is preferably 40° to 50°, more preferably 42° to 48°, and even more preferably 44° to 46°. Furthermore, it is preferable that the phase difference layer exhibits inverse dispersion wavelength characteristics in which the phase difference value increases with the wavelength of the measured light.

[0039] As shown in the figure, when the retardation layer 20 has a laminated structure, the retardation layer 20 has a two-layer laminated structure in which, for example, a first retardation layer (H layer) 21 and a second retardation layer (Q layer) 22 are arranged in order from the polarizer 10 side. The H layer can typically function as a λ / 2 plate, and the Q layer can typically function as a λ / 4 plate. Specifically, Re(550) of the H layer is preferably 200 nm to 300 nm, more preferably 220 nm to 290 nm, and still more preferably 230 nm to 280 nm; Re(550) of the Q layer is preferably 100 nm to 180 nm, more preferably 110 nm to 170 nm, and still more preferably 110 nm to 150 nm. The thickness of the H layer can be adjusted so that the desired in-plane retardation of the λ / 2 plate is obtained. When the H layer is the above-described liquid crystal alignment solidified layer, its thickness is, for example, 2.0 μm to 4.0 μm. The thickness of the Q layer can be adjusted so that the desired in-plane retardation of the λ / 4 plate is obtained. When the Q layer is the above-described liquid crystal alignment solidified layer, its thickness is, for example, 0.5 μm to 2.5 μm. In the present embodiment, the angle formed by the slow axis of the H layer and the absorption axis of the polarizing film is preferably 10° to 20°, more preferably 12° to 18°, and still more preferably 12° to 16°; the angle formed by the slow axis of the Q layer and the absorption axis of the polarizing film is preferably 70° to 80°, more preferably 72° to 78°, and still more preferably 72° to 76°. When the retardation layer 20 has a laminated structure, each layer (for example, the H layer and the Q layer) may exhibit an inverse dispersion wavelength characteristic in which the retardation value increases according to the wavelength of the measurement light, a positive wavelength dispersion characteristic in which the retardation value decreases according to the wavelength of the measurement light, or a flat wavelength dispersion characteristic in which the retardation value hardly changes depending on the wavelength of the measurement light.

[0040] The retardation layer (when having a laminated structure, at least one layer) typically exhibits a refractive index characteristic showing a relationship of nx > ny = nz. Note that "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 not impairing the effects of the present invention, ny > nz or ny < nz may occur. The Nz coefficient of the retardation layer is preferably 0.9 to 1.5, and more preferably 0.9 to 1.3.

[0041] As described above, the phase difference layer is preferably a liquid crystal alignment solidification layer. Examples of the liquid crystal compound include a liquid crystal compound in which the liquid crystal phase is a nematic phase (nematic liquid crystal). Examples of such liquid crystal compounds include liquid crystal polymers and liquid crystal monomers. The mechanism by which the liquid crystal properties of the liquid crystal compound are expressed can be either lyotropic or thermotropic. Liquid crystal polymers and liquid crystal monomers may be used individually or in combination.

[0042] When the liquid crystal compound is a liquid crystal monomer, it is preferable that the liquid crystal monomer is a polymerizable monomer and a crosslinkable monomer. This is because the orientation state of the liquid crystal monomer can be fixed by polymerizing or crosslinking (i.e., curing) the liquid crystal monomer. After oriented the liquid crystal monomer, for example, polymerizing or crosslinking the liquid crystal monomers together can thereby fix the orientation state. Here, polymers are formed by polymerization and a three-dimensional network structure is formed by crosslinking, but these are non-liquid crystal. Therefore, the formed phase difference layer does not undergo transitions to liquid crystal phase, glass phase, or crystalline phase due to temperature changes, which is characteristic of liquid crystal compounds. As a result, the phase difference layer becomes an extremely stable phase difference layer that is not affected by temperature changes.

[0043] The temperature range in which liquid crystal monomers exhibit liquid crystalline properties varies depending on the type. Specifically, the temperature range is preferably 40°C to 120°C, more preferably 50°C to 100°C, and most preferably 60°C to 90°C.

[0044] Any suitable liquid crystal monomer can be used as the above-mentioned liquid crystal monomer. For example, polymerizable mesogenic compounds described in JP 2002-533742 (WO00 / 37585), EP358208 (US5211877), EP66137 (US4388453), WO93 / 22397, EP0261712, DE19504224, DE4408171, and GB2280445 can be used. Specific examples of such polymerizable mesogenic compounds include, for example, BASF's trade name LC242, Merck's trade name E7, and Wacker-Chem's trade name LC-Silicon-CC3767. Nematic liquid crystal monomers are preferred as the liquid crystal monomer.

[0045] C. Inorganic membrane The inorganic film 30 contains silicon. Specifically, it contains a silicon compound. Examples of silicon compounds include silicon oxide, silicon nitride, silicon carbide, and composites thereof. Preferably, the inorganic film contains at least one selected from the group consisting of silicon oxide, silicon carbide, and composites thereof. By providing such an inorganic film, metal corrosion can be suppressed. Specifically, metal corrosion can be suppressed by preventing the movement of iodine contained in (or eluted from) the polarizing film.

[0046] The thickness of the inorganic film is, for example, 50 nm or more, preferably 70 nm or more, and more preferably 90 nm or more. With such a thickness, metal corrosion can be suppressed more effectively. On the other hand, the thickness of the inorganic film is preferably less than 400 nm, more preferably 350 nm or less, even more preferably 300 nm or less, particularly preferably 250 nm or less, and may even be 200 nm or less. By employing an inorganic film, metal corrosion can be suppressed well even with such a thickness. Furthermore, with such a thickness, cosmetic defects (e.g., the occurrence of cracks) can be prevented.

[0047] Inorganic films can be deposited by any suitable method. For example, they can be deposited by physical deposition such as vacuum deposition or sputtering, or by chemical deposition. In the case of chemical deposition, plasma chemical vapor deposition (CVD) is preferred because it allows for film deposition at low temperatures and does not cause thermal damage to the film to be deposited. Specifically, the inorganic film is a deposited film. In this case, the inorganic film can be deposited directly onto the surface of an adjacent layer (e.g., a phase difference layer, a polarizing film). The inorganic film may be partially formed in the region that overlaps with the polarizing film in a plan view, but it is preferable that it be formed over the entire film.

[0048] D.Adhesive layer The thickness of the adhesive layer 40 is preferably 10 μm to 20 μm. The adhesive layer can be composed of any suitable adhesive. Specific examples include acrylic adhesives, rubber adhesives, silicone adhesives, polyester adhesives, urethane adhesives, epoxy adhesives, and polyether adhesives. By adjusting the type, number, combination, and blending ratio of monomers forming the base resin of the adhesive, as well as the amount of crosslinking agent, reaction temperature, reaction time, etc., an adhesive with desired properties for a particular purpose can be prepared. The base resin of the adhesive may be used alone or in combination of two or more types. The base resin is preferably an acrylic resin (specifically, the adhesive layer is preferably composed of an acrylic adhesive).

[0049] E. Fabrication of polarizing plates with phase difference layer A polarizing plate with a phase difference layer according to an embodiment of the present invention can typically be obtained by laminating the polarizing plate and the phase difference layer. The lamination of the polarizing plate and the phase difference layer is carried out, for example, by conveying them on a roll (so-called roll-to-roll). Lamination is typically carried out by transferring a liquid crystal alignment solidification layer formed on a substrate. As shown in the figure, if the phase difference layer has a laminated structure, each phase difference layer may be sequentially laminated (transferred) onto the polarizing plate, or a laminate in which phase difference layers have been pre-laminated may be laminated (transferred) onto the polarizing plate.

[0050] The inorganic film described above can be deposited at an appropriate time so that it is positioned in the desired location. Specifically, it may be deposited before lamination of the polarizing plate and the phase difference layer, or it may be deposited after lamination of the polarizing plate and the phase difference layer.

[0051] F. Image display device The polarizing plate with a phase difference layer described above can be applied to an image display device. Therefore, an image display device according to an embodiment of the present invention has the polarizing plate with a phase difference layer described above.

[0052] Figure 2 is a schematic diagram showing the general configuration of an image display device according to one embodiment of the present invention, using an organic EL display device as an example. Specifically, it is a schematic cross-sectional view showing the general state in which a polarizing plate with a phase difference layer is arranged on an organic EL panel in an organic EL display device according to one embodiment of the present invention. In the organic EL panel 200, the polarizing plate with a phase difference layer 100 is arranged such that the inorganic film 30 is on the organic EL panel body 70 side than the polarizing film 11. Specifically, the polarizing plate with a phase difference layer 100 is attached to the organic EL panel body 70 by an adhesive layer 40.

[0053] The organic EL panel body 70 includes a substrate 71 and an upper structure layer 72 including a circuit layer containing thin-film transistors (TFTs), organic light-emitting diodes (OLEDs), and a sealing film that encapsulates the OLEDs. For example, when a flexible substrate (e.g., a resin substrate) is used as the substrate 71, the resulting organic EL display device can be curved, bent, folded, and wound up. The upper structure layer 72 includes metal layers such as wiring layers and electrode layers, and these metal layers can be corroded by iodine contained in the polarizing film 11. Specifically, metal elution can occur due to oxidation-reduction reactions between the metal contained in the metal layers and iodine. Such reactions can be accelerated, for example, under high temperature and high humidity conditions. With the above-described polarizing plate with a phase difference layer, corrosion of metals contained in the image display device body can be significantly suppressed. Furthermore, the problem of metal corrosion can be solved without redesigning the configuration of the image display device body. [Examples]

[0054] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. The thickness and moisture permeability values ​​were measured using the measurement methods described below. 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 a scanning electron microscope (JEOL Ltd., product name "JSM-7100F"). Thicknesses exceeding 10 μm were measured using a digital micrometer (Anritsu Corporation, product name "KC-351C"). 2. Moisture permeability The moisture permeability was determined using the cup method (JIS Z 0208).

[0055] [Example 1] (Fabrication of polarizing plates) As a thermoplastic resin substrate, an amorphous isophthalic copolymer polyethylene terephthalate film (thickness: 100 μm) in a long length with a Tg of approximately 75°C was used, and one side of this resin substrate was subjected to corona treatment. A PVA aqueous solution (coating solution) was prepared by dissolving 100 parts by weight of a PVA-based resin, which was prepared by mixing polyvinyl alcohol (degree of polymerization 4200, degree of saponification 99.2 mol%) and acetoacetyl-modified PVA (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name "Gosephymer") in a weight ratio of 9:1, with 13 parts by weight of potassium iodide. A PVA aqueous solution was applied to the corona-treated surface of a resin substrate and dried at 60°C to form a 13 μm thick PVA-based resin layer, thereby creating a laminate. The resulting laminate was uniaxially stretched 2.4 times in the longitudinal direction (longitudinal direction) in an oven at 130°C (air-assisted stretching). Next, the laminate was immersed for 30 seconds in an insolubilization bath at a liquid temperature of 40°C (a boric acid aqueous solution obtained by mixing 4 parts by weight of boric acid with 100 parts by weight of water) (insolubilization treatment). Next, the polarizing film was immersed for 60 seconds in a staining bath at a liquid temperature of 30°C (an iodine aqueous solution obtained by mixing iodine and potassium iodide in a weight ratio of 1:7 with 100 parts by weight of water) while adjusting the concentration so that the transmittance (Ts) of the final polarizing film would be the desired value (staining treatment). Next, the material was immersed for 30 seconds in a crosslinking bath at a liquid temperature of 40°C (a boric acid aqueous solution obtained by mixing 3 parts by weight of potassium iodide and 5 parts by weight of boric acid with 100 parts by weight of water) (crosslinking treatment). Subsequently, the laminate was immersed in a boric acid aqueous solution (boric acid concentration 4% by weight, potassium iodide concentration 5% by weight) at a liquid temperature of 70°C, and uniaxially stretched in the longitudinal direction (longitudinal direction) between rolls with different peripheral speeds to achieve a total stretch ratio of 5.5 times (underwater stretching treatment). Subsequently, 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). Subsequently, the material was dried in an oven maintained at approximately 90°C while being brought into contact with a SUS (stainless steel) heated roll whose surface temperature was maintained at approximately 75°C (drying shrinkage treatment). In this way, a polarizing film with a thickness of 5.4 μm was formed on the resin substrate, and a laminate having a resin substrate / polarizing film structure was obtained.

[0056] A COP film with an HC layer formed on it was bonded to the polarizing film side of the obtained laminate as a protective layer via an ultraviolet-curable adhesive (thickness after curing: 1.5 μm). Subsequently, the resin substrate was peeled off from the polarizing film to obtain a polarizing plate having the structure of HC layer / COP film / adhesive layer / polarizing film. The COP film with the HC layer was obtained by forming a 2 μm thick hard coat layer on a cycloolefin-based unstretched film (manufactured by Zeon Corporation, 25 μm thick).

[0057] (Fabrication of phase difference layer) A liquid crystal composition (coating solution) was prepared by dissolving 10 g of a polymerizable liquid crystal exhibiting a nematic liquid crystal phase (BASF: trade name "Paliocolor LC242", represented by the following formula) and 3 g of a photopolymerization initiator for the polymerizable liquid crystal compound (BASF: trade name "Irgacure 907") in 40 g of toluene. [ka]

[0058] The surface of a polyethylene terephthalate (PET) film (38 μm thick) was rubbed using a rubbing cloth to perform an orientation treatment. The orientation direction was set so that, when bonded to a polarizing plate, it was 15° from the viewing side relative to the direction of the absorption axis of the polarizing film. The liquid crystal coating solution was applied to this orientation-treated surface using a bar coater and heated and dried at 90°C for 2 minutes to orient the liquid crystal compound. The liquid crystal layer thus formed was subjected to a metal halide lamp treatment of 1 mJ / cm². 2 A liquid crystal alignment solidification layer A (H layer) was formed on a PET film by irradiating it with light and curing the liquid crystal layer. The thickness of liquid crystal alignment solidification layer A was 2.5 μm, and the in-plane phase difference Re(550) was 270 nm. Furthermore, liquid crystal alignment solidification layer A exhibited refractive index characteristics of nx>ny=nz.

[0059] A liquid crystal alignment solidification layer B (Q layer) was formed on a PET film in the same manner as described above, except that the coating thickness was changed and the orientation direction was set to 75° from the viewing side relative to the direction of the absorption axis of the polarizing film. The thickness of the liquid crystal alignment solidification layer B was 1.5 μm, and the in-plane phase difference Re(550) was 140 nm. Furthermore, the liquid crystal alignment solidification layer B exhibited refractive index characteristics of nx>ny=nz.

[0060] (Fabrication of polarizing plates with phase difference layer) On the polarizing film side of the obtained polarizing plate, the obtained liquid crystal alignment cured layer A (H layer) and liquid crystal alignment cured layer B (Q layer) were transferred in this order. At this time, the transfer (lamination) was performed such that the angle formed by the absorption axis of the polarizing film and the slow axis of the alignment cured layer A was 15°, and the angle formed by the absorption axis of the polarizing film and the slow axis of the alignment cured layer B was 75°. Each transfer was performed via an ultraviolet curable adhesive (thickness after curing: 1 μm) while being roll-conveyed.

[0061] Thereafter, a silicon oxycarbide film with a thickness of 100 nm was formed on the surface of the liquid crystal alignment cured layer B. Specifically, a polarizing plate with a liquid crystal alignment cured layer laminated thereon was set in a roll-to-roll type CVD film forming apparatus, and the inside of the vacuum chamber was evacuated to 1×10 -3 Pa. After that, while the polarizing plate was being run, hexamethyldisiloxane (HMDSO) vaporized by heating, which is a film forming material, and oxygen were introduced into the chamber at flow rates of 25 sccm and 700 sccm, respectively, to make the pressure about 1.0 Pa, and discharge was performed under the conditions of a frequency of 80 kHz and a power of 1.0 kW of a plasma generation power source to generate plasma and perform film formation. Next, an adhesive layer with a thickness of 15 μm was formed on the surface of the silicon oxycarbide film with an acrylic adhesive to obtain a polarizing plate with a retardation layer. In the obtained polarizing plate with a retardation layer, the moisture permeability at 40 °C and 92% RH of the laminated portion from the liquid crystal alignment cured layer A to the silicon oxycarbide film was 40 g / m 2 ·24 h.

[0062] [Example 2] A polarizing plate with a retardation layer was obtained in the same manner as in Example 1 except that the thickness of the silicon oxycarbide film was 200 nm. In the obtained polarizing plate with a retardation layer, the moisture permeability at 40 °C and 92% RH of the laminated portion from the liquid crystal alignment cured layer A to the silicon oxycarbide film was 30 g / m 2 ·24 h.

[0063] [Example 3] A polarizing plate with a phase difference layer was obtained in the same manner as in Example 1, except that a 100 nm thick silicon oxide film was deposited by reactive sputtering instead of depositing a 100 nm thick silicon oxide carbide film. The silicon oxide film was deposited by attaching a pure Si target (manufactured by Daido Steel Co., Ltd.) to an AC sputtering apparatus (AC: 40 kHz), setting a polarizing plate with a liquid crystal alignment solidification layer laminated on top, and using a vacuum of 1.0 × 10⁻⁶. -4 After evacuating to a pressure of Pa, Ar gas and oxygen (O2) gas were introduced into the chamber so that the oxygen partial pressure (O2 / (Ar+O2)) was 0.05, resulting in a pressure of approximately 0.15 Pa and a power density of 2.23 W / cm². 2 This was done by discharging under the following conditions. In the resulting polarizing plate with a phase difference layer, the moisture permeability of the laminated portion from the liquid crystal alignment solidification layer A to the silicon oxide film at 40°C and 92%RH is 30 g / m². 2 It was 24 hours.

[0064] [Example 4] A polarizing plate with a phase difference layer was obtained in the same manner as in Example 1, except that the thickness of the silicon oxide carbide film was set to 400 nm. In the resulting polarizing plate with a phase difference layer, the moisture permeability of the laminated portion from the liquid crystal alignment solidification layer A to the silicon oxide carbide film at 40°C and 92%RH is 20 g / m². 2 It was 24 hours.

[0065] [Example 5] A silicon oxide carbide film was formed on the polarizing film surface of a polarizing plate obtained in the same manner as in Example 1, under the same conditions as in Example 2. Then, liquid crystal alignment solidification layer A (H layer) and liquid crystal alignment solidification layer B (Q layer) were transferred to the surface of the silicon oxide carbide film in the same manner as in Example 1, in that order. Subsequently, an adhesive layer with a thickness of 15 μm was formed on the surface of the liquid crystal alignment solidification layer B using an acrylic adhesive to obtain a polarizing plate with a phase difference layer. In the resulting polarizing plate with a phase difference layer, the moisture permeability of the laminated portion from the silicon oxide carbide film to the liquid crystal alignment solidification layer B at 40°C and 92%RH is 30 g / m². 2 It was 24 hours.

[0066] [Comparative Example 1] A polarizing plate with a phase difference layer was obtained in the same manner as in Example 1, except that a silicon oxide carbide film was not formed. In the resulting polarizing plate with a phase difference layer, the moisture permeability of the laminated portion from liquid crystal alignment solidification layer A to liquid crystal alignment solidification layer B at 40°C and 92%RH is 400-500 g / m². 2 It was 24 hours.

[0067] [Comparative Example 2] A polarizing plate with a phase difference layer was obtained in the same manner as in Example 1, except that a 400 nm thick organic film was formed instead of a 100 nm thick silicon oxide carbide film. Specifically, 15 parts of acrylic resin (manufactured by Kusumoto Chemical Co., Ltd., product name "B-811") and 85 parts (on a solid content basis) of thermoplastic epoxy resin (manufactured by Mitsubishi Chemical Corporation, product name "jER(registered trademark) YX6954BH30") were dissolved in 80 parts of methyl ethyl ketone to obtain a resin solution (20%). This resin solution was applied to the surface of liquid crystal alignment solidification layer B using a wire bar, and the applied film was dried at 60°C for 5 minutes to form an organic film. In the resulting polarizing plate with a phase difference layer, the moisture permeability of the laminated portion from the liquid crystal alignment solidification layer A to the organic film at 40°C and 92%RH is 400-500 g / m². 2 It was 24 hours.

[0068] [Reference example 1] A polarizing plate with a phase difference layer was obtained in the same manner as in Example 1, except that the polarizing plate shown below was used as the polarizing plate, a silicon oxide carbide film was not formed, and the thickness of the adhesive layer was set to 30 μm.

[0069] (Fabrication of polarizing plates) A 12 μm thick polarizing film was fabricated by uniaxially stretching a 30 μm thick polyvinyl alcohol (PVA) resin film (manufactured by Kuraray, product name "PE3000") in the longitudinal direction using a roll stretching machine to 5.9 times its length, while simultaneously applying swelling, dyeing, crosslinking, and washing treatments in that order, and finally drying treatment. The above swelling treatment involved stretching the material 2.2 times while treating it with pure water at 20°C. Next, the dyeing treatment involved stretching the material 1.4 times while treating it in an aqueous solution at 30°C with an iodine-to-potassium iodide weight ratio of 1:7, where the iodine concentration was adjusted so that the resulting polarizing film had a single-layer transmittance of 45.0%. Next, the crosslinking treatment was performed in two stages. In the first stage, the material was stretched 1.2 times while treating it in an aqueous solution of boric acid and potassium iodide at 40°C. The boric acid content of the aqueous solution for the first stage of crosslinking was 5.0% by weight, and the potassium iodide content was 3.0% by weight. In the second stage of crosslinking, the material was stretched 1.6 times while treating it in an aqueous solution of boric acid and potassium iodide at 65°C. The boric acid content of the aqueous solution for the second stage of crosslinking was 4.3% by weight, and the potassium iodide content was 5.0% by weight. Next, the washing treatment was performed with an aqueous potassium iodide solution at 20°C. The potassium iodide content of the washing solution was 2.6% by weight. Finally, the polarizing film was obtained by drying at 70°C for 5 minutes.

[0070] A TAC film (thickness 25 μm) with an HC layer (thickness 7 μm) formed on both sides via a polyvinyl alcohol-based adhesive, and a TAC film with a thickness of 25 μm, were bonded to each side of the obtained polarizing film to obtain a polarizing plate having the structure of HC layer / TAC film / adhesive layer / polarizing film / adhesive layer / TAC film. In the resulting polarizing plate with a phase difference layer, the moisture permeability of the laminated portion from the TAC film to the liquid crystal alignment solidification layer B at 40°C and 92%RH is 300-400 g / m². 2 It was 24 hours.

[0071] [Reference example 2] A polarizing plate obtained in the same manner as in Reference Example 1 was bonded to the following phase difference film via an acrylic adhesive (thickness 5 μm). Then, a 15 μm thick adhesive layer was formed on the surface of the phase difference film using the acrylic adhesive to obtain a polarizing plate with a phase difference layer. The phase difference film was bonded so that the absorption axis of the polarizing film and the slow phase axis of the phase difference film formed a 45° angle. In the resulting polarizing plate with a phase difference layer, the moisture permeability of the laminated portion from the TAC film to the phase difference film at 40°C and 92%RH is 60 g / m². 2 It was 24 hours.

[0072] (Preparation of phase difference film) Polymerization was carried out using a batch polymerization apparatus consisting of two vertical reactors equipped with stirring blades and reflux condensers controlled to 100°C. The mixture consisted of 29.60 parts by mass (0.046 mol) of bis[9-(2-phenoxycarbonylethyl)fluoren-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 × 10⁻¹⁶ calcium acetate monohydrate as a catalyst. -2 Part of mass (6.78×10 -5 A mol (mol) of polymer was added. After purging the reactor with reduced pressure using nitrogen, the reactor was heated with a heat transfer medium, and stirring was started when the internal temperature reached 100°C. Forty minutes after the start of heating, the internal temperature was raised to 220°C, and while controlling the pressure to maintain this temperature, the pressure was reduced to 13.3 kPa 90 minutes after reaching 220°C. The phenol vapor produced as a by-product of the polymerization reaction was directed to a reflux condenser at 100°C, and the monomer components contained in the phenol vapor were returned to the reactor. The uncondensed phenol vapor was directed to a condenser at 45°C and recovered. Nitrogen was introduced into the first reactor to restore the pressure to atmospheric pressure, and then the oligomerized reaction mixture in the first reactor was transferred to the second reactor. Next, heating and depressurization in the second reactor were started, and the internal temperature reached 240°C and the pressure 0.2 kPa in 50 minutes. Polymerization was then allowed to proceed until the predetermined stirring power was reached. Once the predetermined power level was reached, nitrogen was introduced into the reactor to restore pressure, and the resulting polyester carbonate resin was extruded into water. The strands were then cut to obtain pellets.

[0073] The obtained polyester carbonate resin (pellets) was vacuum-dried at 80°C for 5 hours. Then, a long resin film with a thickness of 135 μm was produced using a film-making apparatus 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: 120~130°C), and a winding machine. 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 phase difference film with a thickness of 50 μm. The Re(550) of the obtained phase difference film was 141 nm, the Re(450) / Re(550) was 0.82, and the Nz coefficient was 1.12.

[0074] The following evaluations were conducted on the examples and comparative examples. The evaluation results are summarized in Table 1. <Rating> 1. Corrosive A silver nanowire solution (MERCK, nanowire size: 115 nm in diameter, 20 μm to 50 μm in length, 0.5% solids isopropyl alcohol (IPA) solution) was applied to one side of a 50 μm polyethylene terephthalate (PET) film using a wire bar to a wet film thickness of 15 μm, and dried in a 100°C oven for 5 minutes to form a silver nanowire coating. Next, an overcoat solution (solids concentration: approximately 1%) containing 99 parts methyl isobutyl ketone (MIBK), 1 part pentaerythritol tetraacrylate (PETA), and 0.03 parts photopolymerization initiator (BASF, product name "Irgacure 907") was applied to the surface of the silver nanowire coating using a wire bar to a wet film thickness of 10 μm, and dried in a 100°C oven for 5 minutes. Next, the overcoat coating was cured by irradiation with active energy rays to produce a metal film having the structure of PET film / silver nanowire layer / overcoat layer (thickness 100 nm). This metal film was bonded to a 0.5 mm thick glass plate using an adhesive (15 μm) to obtain a laminate of metal film / adhesive / glass plate. The resistance of the obtained laminate was measured using a non-contact resistance meter (Napson Corporation, product name "EC-80") and was found to be 50 Ω / □. The obtained polarizing plate with a phase difference layer was bonded to the surface of the overcoat layer of the metal film of the laminate to create a test sample. The resistance value of this test sample was measured using a non-contact resistance meter and was taken as the initial resistance value. Furthermore, the test sample was subjected to a reliability test (left in an environment of 85°C and 85%RH for 240 hours, and then left in an environment of 23°C and 55%RH for 2 hours), and the resistance value was measured in the same manner as above. The resistance increase rate was calculated using the following formula and evaluated according to the following criteria. Resistance increase rate (%) = {(Resistance after reliability test - Initial resistance) / Initial resistance} × 100 (Evaluation Criteria) Good: Resistance increase rate is less than 2000% Defective: Resistance increase rate of 2000% or more 2. Exterior After bonding the resulting polarizing plate with a phase difference layer to alkali-free glass, it was left in an environment of 85°C and 85% RH for 240 hours. The appearance was then visually inspected to check for cracks and delamination.

[0075] [Table 1]

[0076] In each example, it can be seen that metal corrosion is suppressed. In Examples 4 and 5, cracks were observed in the silicon oxide carbide film. In Reference Examples 1 and 2, delamination was observed between the polarizing plate with phase difference layer (adhesive layer) and the glass. [Industrial applicability]

[0077] Polarizing plates with a phase difference layer according to embodiments of the present invention can be used in image display devices and are also suitably used in curved, bendable, foldable, or rollable image display devices. Typical image display devices include liquid crystal displays, organic EL displays, and inorganic EL displays. [Explanation of Symbols]

[0078] 10 Polarizing plates 11 Polarizing film 12 protective layers 20-bit phase difference layer 21 First phase difference layer 22 Second phase difference layer 30 Inorganic membranes 40 adhesive layer 100-position phase difference layer polarizing plate

Claims

[Claim 1] A polarizing plate containing a polarizing film having a first principal surface and a second principal surface facing each other and containing iodine, An adhesive layer disposed on the second main surface side of the polarizing film, A phase difference layer disposed between the polarizing film and the adhesive layer, Displaced between the polarizing film and the adhesive layer, the film includes an inorganic film containing silicon. The thickness of the laminated portion from the polarizing plate to the layer adjacent to the adhesive layer is 50 μm or less. Polarizing plate with retardation layer.

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