Polarizing plate set and liquid crystal panel

Abstract

The present application provides a polarizing plate set in which warping of a liquid crystal panel is suppressed. A polarizing plate set including a front-side polarizing plate disposed on a viewing side of a liquid crystal cell and a back-side polarizing plate disposed on a back side of the liquid crystal cell, the front-side polarizing plate and the back-side polarizing plate including a polarizing film, when a distance from a face of the polarizing film contained in the front-side polarizing plate on a liquid crystal cell side to a face of the front-side polarizing plate on the liquid crystal cell side is set as L1 (μm) and a distance from a face of the polarizing film contained in the back-side polarizing plate on the liquid crystal cell side to a face of the back-side polarizing plate on the liquid crystal cell side is set as L2 (μm), at least either one of L1 (μm) and L2 (μm) is 35 μm or less, and a moisture permeability of at least one selected from the front-side polarizing plate and the back-side polarizing plate at a temperature of 40°C and a humidity of 90% RH on the liquid crystal cell side of the polarizing film is 400 g / m 2 • Resin layer of 24 hours or less.

Description

Technical Field

[0001] This invention relates to polarizing plate assemblies and liquid crystal panels. Background Technology

[0002] In image display devices and the like, liquid crystal panels are used in which polarizers are disposed on the viewing side and the back side of the liquid crystal cell, respectively. It is known that liquid crystal panels sometimes warp when used in high-temperature environments (Patent Documents 1 and 2).

[0003] Patent Document 1 proposes reducing the warpage of a liquid crystal panel under high-temperature conditions by ensuring that the tensile elastic modulus of the protective layer in the polarizer on the side of the polarizer assembly that is warped into a concave shape satisfies a specified formula. Patent Document 2 proposes reducing the warpage of a liquid crystal panel under high-temperature conditions by making the distance from the side of the polarizer of the integrated front panel polarizer away from the front panel to the liquid crystal cell greater than the distance from the side of the polarizer of the rear panel polarizer closer to the front panel to the liquid crystal cell. Patent Document 3 proposes a liquid crystal display device that, in order to reduce the warpage of the liquid crystal panel generated during pressure degassing, sets a specific ratio to the values ​​calculated from the thickness, elastic modulus, and dimensional change rate of the polarizer, as well as the distance from the polarizer to the liquid crystal cell.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2018-72533

[0007] Patent Document 2: Japanese Patent Application Publication No. 2017-83857

[0008] Patent Document 3: International Publication No. 2015 / 156250 Summary of the Invention

[0009] The problem that the invention aims to solve

[0010] Warping in high-temperature environments (e.g., 85°C) is mostly due to the shrinkage of the polarizer (hereinafter also referred to as PVA polarizer), which includes a polyvinyl alcohol resin film as a component of the polarizer adhered to the panel, when heated. PVA polarizers, in particular, tend to shrink significantly in the stretching direction due to heating. Such warping of liquid crystal panels caused by PVA polarizers can sometimes be reduced by the polarizer assembly described in the aforementioned patent documents.

[0011] On the other hand, for example, when transporting LCD TV modules by sea, the backlight can sometimes cause warping of the LCD panel after the packaging is opened and the backlight is turned on. As LCD TVs become larger, the warping of polarizing plates used in large LCD TVs increases due to their larger area, relative to the small dimensional changes between the front and back polarizing plates. Therefore, suppressing warping becomes very important compared to applications with smaller areas.

[0012] The object of the present invention is to provide a polarizing plate assembly that suppresses warping of a liquid crystal panel.

[0013] Methods for solving problems

[0014] The present invention provides the following polarizing plate assembly and liquid crystal panel.

[0015] [1] A polarizing plate assembly comprising a front-side polarizing plate disposed on the viewing side of a liquid crystal cell and a back-side polarizing plate disposed on the back side of the liquid crystal cell.

[0016] The aforementioned front-side polarizing plate and the aforementioned back-side polarizing plate include polarizing filters.

[0017] When the distance from the surface of the polarizer included in the front polarizer to the surface of the liquid crystal cell on the front polarizer is defined as L1 (μm), and the distance from the surface of the polarizer included in the back polarizer to the surface of the liquid crystal cell on the back polarizer is defined as L2 (μm), at least either L1 (μm) or L2 (μm) is 35 μm or less.

[0018] At least one of the aforementioned front-side polarizer and the aforementioned back-side polarizer has a permeability of 400 g / m³ at a temperature of 40°C and a humidity of 90% RH on the liquid crystal cell side of the aforementioned polarizer. 2 • Resin layer for less than 24 hours.

[0019] [2] According to the polarizing plate assembly described in [1], the sum of L1 (μm) and L2 (μm) is 60 μm or less.

[0020] [3] According to the polarizing plate assembly described in [1] or [2], the absolute value of the difference between L1 (μm) and L2 (μm) is 3 μm or less.

[0021] [4] According to any one of [1] to [3], the polarizing plates contained in the front polarizing plate and the back polarizing plate have substantially the same thickness.

[0022] [5] According to any one of [1] to [4], the polarizing plate assembly wherein both the front polarizing plate and the back polarizing plate have a permeability of 400 g / m² at a temperature of 40°C and a humidity of 90% RH on the liquid crystal cell side of the polarizing plate. 2 • Resin layer for less than 24 hours.

[0023] [6] According to any one of [1] to [5], the front polarizer and the back polarizer both contain a cyclic cyclic olefin resin film on the liquid crystal cell side of the polarizer.

[0024] [7] According to any one of [1] to [6], the front polarizer and the back polarizer each contain a triacetyl cellulose resin film on the side of the polarizer opposite to the liquid crystal cell.

[0025] [8] A liquid crystal panel comprising a polarizing plate assembly and a liquid crystal cell as described in any one of [1] to [7].

[0026] Invention Effects

[0027] According to the present invention, a polarizing plate assembly is provided that suppresses warping of a liquid crystal panel. Attached Figure Description

[0028] Figure 1 This is a schematic cross-sectional view showing the layer structure of the polarizing plate assembly of the present invention.

[0029] Figure 2 This is a schematic cross-sectional view showing another layer of the polarizing plate assembly of the present invention. Detailed Implementation

[0030] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings, but the present invention is not limited to the following embodiments. In all the following drawings, the scale has been appropriately adjusted for ease of understanding of the constituent elements, and the scale of each constituent element shown in the drawings may not be consistent with the actual scale of the constituent elements.

[0031] <Polarizing Plate Assembly>

[0032] Reference Figure 1 One embodiment of the polarizing plate assembly of the present invention will be described. Figure 1 The polarizing plate assembly 1 shown consists of a front-side polarizing plate 100 disposed on the viewing side of the liquid crystal cell 300 and a back-side polarizing plate 200 disposed on the back side of the liquid crystal cell 300. The front-side polarizing plate 100 and the back-side polarizing plate 200 can be of the same type or different types. By attaching the polarizing plate assembly to the liquid crystal cell, a liquid crystal panel can be manufactured.

[0033] The front-side polarizer 100 and the back-side polarizer 200 can be square, for example, preferably square with a long side and a short side, and more preferably rectangular. The size of the front-side polarizer 100 and the back-side polarizer 200 is preferably a square shape with a long side of 660 mm or more and a short side of 370 mm or more (equivalent to a 32-inch type), preferably a square shape with a long side of 800 mm or more and a short side of 450 mm or more (equivalent to a 40-inch type). Furthermore, the size of the front-side polarizer 100 and the back-side polarizer 200 is preferably a square shape with a long side of 1000 mm or more and a short side of 550 mm or more (equivalent to a 50-inch type), preferably a square shape with a long side of 1300 mm or more and a short side of 700 mm or more (equivalent to a 60-inch type).

[0034] The polarizer assembly 1 can be arranged in the liquid crystal cell such that the transmission axes of the front-side polarizer 100 and the back-side polarizer 200 are substantially perpendicular to each other. The angle between the transmission axis of the back-side polarizer 200 and the transmission axis of the front-side polarizer 100 can be, for example, in the range of 90±5°, preferably in the range of 90±1°, and more preferably in the range of 90±0.5°.

[0035] The top-view shape of the front-side polarizer 100, the back-side polarizer 200, and the liquid crystal cell 300 can be, for example, square, preferably a square shape with a long side and a short side, and more preferably rectangular. When the top-view shape of the front-side polarizer 100, the back-side polarizer 200, and the liquid crystal cell 300 is rectangular, the polarizer assembly 1 can be arranged such that the absorption axis direction of the polarizer of the front-side polarizer 100 is approximately parallel to the long side direction of the liquid crystal cell, and the absorption axis direction of the polarizer of the back-side polarizer 200 is approximately parallel to the short side direction of the liquid crystal cell; or it can be arranged such that the absorption axis direction of the polarizer of the front-side polarizer 100 is approximately parallel to the short braiding direction of the liquid crystal cell, and the absorption axis direction of the polarizer of the back-side polarizer 200 is approximately parallel to the long braiding direction of the liquid crystal cell. "Approximately parallel" means, for example, that the angle formed by the absorption axis of the polarizer and the long or short side of the liquid crystal cell can be 5° or less, preferably 3° or less, and more preferably 1° or less.

[0036] Although not shown, both the front-side polarizer 100 and the back-side polarizer 200 include polarizers and resin layers. Additionally, both the front-side polarizer 100 and the back-side polarizer 200 include an adhesive layer (not shown) for bonding them to the liquid crystal cell. Besides the polarizers and the resin layer described later, the front-side polarizer 100 and the back-side polarizer 200 may also include, for example, an adhesive layer, a phase retardation layer, and a protective film.

[0037] Regarding polarizer assembly 1, when the distance from the surface of the polarizer included in the front polarizer 100 to the surface of the liquid crystal cell 300 side of the front polarizer 100 is set as L1 (μm), and the distance from the surface of the polarizer included in the back polarizer 200 to the surface of the liquid crystal cell 300 side of the back polarizer 200 is set as L2 (μm), at least either L1 (μm) or L2 (μm) is 35 μm or less, and the permeability (hereinafter, for simplicity, also referred to as permeability) of at least one of the front polarizer 100 and the back polarizer 200 at a temperature of 40°C and a humidity of 90% RH on the side of the polarizer is 400 g / m². 2 • Resin layer with a lifespan of 24 hours or less (not shown). The surface of the front polarizer 100 on the liquid crystal cell 300 side and the surface of the back polarizer 200 on the liquid crystal cell 300 side refer to the surface of the adhesive layer (excluding the separator) contained in the front polarizer 100 and the back polarizer 200 on the liquid crystal cell side.

[0038] The inventors have discovered that when a polarizer, a component of a polarizer attached to a liquid crystal cell, is exposed to a high-humidity environment for an extended period, moisture is gradually absorbed. If the backlight is then turned on and time passes, the polarizer deforms as the moisture moves, leading to warping of the liquid crystal cell. For example, when transporting LCD TV modules by ship, the high humidity at the bottom of the ship causes the polarizer attached to the liquid crystal cell to become hygroscopic over time. When the packaging is opened in this state, methods that only reduce the contractile force of the polarizer and the polarizer plate are insufficient to prevent moisture intrusion from the outside, resulting in increased water absorption and consequently, increased deformation. The inventors have conducted in-depth research and found that by setting at least one of L1 (μm) and L2 (μm) to 35 μm or less, and by having at least one of the front-side and back-side polarizers with a resin layer on the liquid crystal cell side of the polarizer having a moisture permeability of 400 g / m²·24hr or less, there is a tendency to easily reduce the warping of the liquid crystal panel. This is presumably because it can suppress the intrusion of moisture from the liquid crystal cell side of the polarizer and reduce the energy of strain that accumulates on the side closer to the liquid crystal cell than the polarizer.

[0039] From the viewpoint of the warpage of the liquid crystal panel, at least either L1 (μm) or L2 (μm) is preferably 30 μm or less, more preferably 25 μm or less, and even more preferably 20 μm or less. In this specification, the warpage can be measured according to the method described in the embodiments section below.

[0040] From the viewpoint of the warpage of the liquid crystal panel, L1 (μm) and L2 (μm) are both preferably 35 μm or less, more preferably 30 μm or less, even more preferably 25 μm or less, and particularly preferably 20 μm or less.

[0041] From the viewpoint of the warpage of the liquid crystal panel, the sum of L1 (μm) and L2 (μm) is preferably 60 μm or less, more preferably 50 μm or less, and even more preferably 40 μm or less.

[0042] To ensure that the strain forces exerted on the liquid crystal cell by the front-side polarizer and the back-side polarizer are equal and cancel each other out, L1 (μm) and L2 (μm) can be set to the same level. From the viewpoint of the warpage of the liquid crystal panel, the absolute value of the difference between L1 (μm) and L2 (μm) is preferably 3 μm or less, more preferably 2 μm or less, even more preferably 1 μm or less, and particularly preferably 0.

[0043] [Polarizing filter]

[0044] Polarizers have the following properties: they absorb linearly polarized light with a vibration plane parallel to its absorption axis and transmit linearly polarized light with a vibration plane orthogonal to the absorption axis (parallel to the transmission axis). A component consisting of a polarizer and a resin layer laminated together is also called a linear polarizer.

[0045] Polarizing films can be films on known polyvinyl alcohol resins with iodine adsorbed on them. Polarizing films can be manufactured, for example, by the following steps: uniaxial stretching of the polyvinyl alcohol resin, dyeing the polyvinyl alcohol resin with iodine to adsorb the iodine, treating the iodine-adsorbed polyvinyl alcohol resin with an aqueous boric acid solution, and washing with water after treatment with the aqueous boric acid solution.

[0046] Polyvinyl alcohol-based resins are obtained by saponifying polyvinyl acetate-based resins. Besides polyvinyl acetate as a homopolymer of vinyl acetate, copolymers of vinyl acetate and other monomers capable of copolymerizing with it can also be used as polyvinyl acetate-based resins. Examples of other monomers capable of copolymerizing with vinyl acetate include unsaturated carboxylic acid compounds, olefin compounds, vinyl ether compounds, unsaturated sulfone compounds, and (meth)acrylamide compounds having an ammonium group. In this specification, "(meth)acrylic acid" refers to at least one selected from acrylic acid and methacrylic acid. The same applies to "(meth)acrylate" and the like.

[0047] The degree of saponification of polyvinyl alcohol (PVA) resins is typically between 85 mol% and 100 mol%, preferably 98 mol% or higher. PVA resins can be modified, and aldehyde-modified PVA such as polyvinyl formal or polyvinyl acetal can also be used. The degree of polymerization of PVA resins is typically between 1000 and 10000, preferably between 1500 and 5000.

[0048] From the viewpoint that low water absorption is preferable, the thickness of the polarizer is preferably 30 μm or less, more preferably 25 μm or less, even more preferably 20 μm or less, and particularly preferably 15 μm or less. The thickness of the polarizer is typically 2 μm or more, preferably 3 μm or more, and for example, 5 μm or more. To counteract the deformation of the polarizers in the front-side polarizer 100 and the back-side polarizer 200, it is preferable to use polarizers of substantially the same thickness in both the front-side polarizer 100 and the back-side polarizer 200.

[0049] [Resin Layer]

[0050] The resin layer can be applied directly to one or both sides of the polarizer, or with the aid of an adhesive layer described later, and serves to protect the polarizer, especially its surface. The resin layer can be an optically transparent thermoplastic resin film or coating. In the case where the front-side polarizer 100 and the back-side polarizer 200 contain multiple resin layers, the resin layers can be of the same type or different types.

[0051] Thermoplastic resin film can be laminated to one or both sides of a polarizing film. As a thermoplastic resin film, for example, it can be a thermoplastic resin film that is light-transmitting, preferably optically transparent. Examples include chain polyolefin resins (polyethylene resins, polypropylene resins, polymethylpentene resins, etc.), cyclic polyolefin resins (norbornene resins, etc.); cellulose resins such as triacetyl cellulose; polyester resins such as polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate; polycarbonate resins; ethylene-vinyl acetate resins; polystyrene resins; polyamide resins; polyetherimide resins; (meth)acrylic resins such as poly(meth)acrylate resins; polyimide resins; polyethersulfone resins; polysulfone resins; polyvinyl chloride resins; polyvinylidene chloride resins; polyvinyl alcohol resins; polyvinyl alcohol acetal resins; polyetherketone resins; polyetheretherketone resins; polyethersulfone resins; and polyamide-imide resins. Thermoplastic resins can be used alone or in combination of two or more. Among them, from the viewpoint of strength and light transmittance, triacetyl cellulose resin films, cyclic polyolefin resin films, and (meth)acrylic resin films are preferred.

[0052] Thermoplastic resin films may or may not have a phase difference. Thermoplastic resin films can contain, as needed, plasticizers, ultraviolet absorbers, infrared absorbers, colorants such as pigments and dyes, fluorescent whitening agents, dispersants, heat stabilizers, light stabilizers, antistatic agents, antioxidants, lubricants, etc.

[0053] The thickness of the thermoplastic resin film can be, for example, 60 μm or less, but from the viewpoint of reducing the distance between the polarizer and the liquid crystal cell, it is preferably 50 μm or less, more preferably 40 μm or less. Additionally, it is typically 1 μm or more, preferably 5 μm or more, and even more preferably 15 μm or more.

[0054] Surface treatment layers (coatings) such as hard coatings, anti-reflective layers, and antistatic layers can also be formed on the surface of the thermoplastic resin film opposite to the polarizer.

[0055] By applying a hard coating to a thermoplastic resin film, a resin film with improved hardness and scratch resistance can be produced. The hard coating can be formed from a cured composition of a hard coating forming material containing an active energy radiation-curable resin. Examples of UV-curable resins include acrylic resins, silicone resins, polyester resins, urethane resins, amide resins, and epoxy resins. To improve strength, the hard coating may contain additives. Additives are not limited and examples include inorganic microparticles, organic microparticles, or mixtures thereof.

[0056] The resin layer as a coating film can be, for example, a coating composition formed by coating and curing the composition used in the aforementioned hard coating layer, a cationic curable composition such as epoxy resin, or a free radical curable composition such as (meth)acrylate. Alternatively, the resin layer as a coating film can be formed by coating the surface of the polarizer with an aqueous solution of a polyvinyl alcohol-based resin or the like and then drying it. The resin layer as a coating film may, as needed, contain plasticizers, ultraviolet absorbers, infrared absorbers, colorants such as pigments and dyes, fluorescent whitening agents, dispersants, heat stabilizers, light stabilizers, antistatic agents, antioxidants, lubricants, etc.

[0057] The thickness of the resin layer as a coating film can be, for example, 30 μm or less, preferably 25 μm or less, more preferably 20 μm or less, even more preferably 15 μm, and particularly preferably 10 μm. The thickness of the resin layer as a coating film can be, for example, 0.1 μm or more.

[0058] [Water permeability is 400g / m³] 2 • Resin layer for less than 24 hours

[0059] At least one of the front-side polarizer 100 and the back-side polarizer 200 contains a permeability of 400 g / m² on the liquid crystal cell side of the polarizer.2 • A resin layer with a permeability of 24 hours or less (hereinafter, for simplicity, it is also referred to as a low-permeability resin layer). In this specification, permeability can be measured according to the method described in the examples section below.

[0060] From the perspective of LCD panel warpage, a low moisture permeability resin layer preferably contains a moisture permeability of 300 g / m². 2 • Less than 24 hours, more preferably 200g / m 2 • Less than 24 hours, preferably 100g / m 2 • Less than 24 hours, preferably 80g / m 2 • Resin layer with a lifespan of less than 24 hours. A low-permeability resin layer can be, for example, 10 g / m³. 2 • 24 hours or more, preferably 30g / m 2 ·More than 24hr.

[0061] Preferably, both the front-side polarizer 100 and the back-side polarizer 200 comprise a low-humidity-permeability resin layer. When both the front-side polarizer 100 and the back-side polarizer 200 comprise a low-humidity-permeability resin layer, the low-humidity-permeability resin layers can be of the same type or different types. Besides the aforementioned thermoplastic resin films and coatings, the low-humidity-permeability resin layer can also be a stretched thermoplastic resin film, a coating prepared by casting, or a layer of cured material containing a photocurable resin composition. Preferably, the low-humidity-permeability resin layer is a thermoplastic resin film comprising a resin with cyclic polyolefins as the main monomer.

[0062] [Adhesive Layer]

[0063] The bonding layer can be a layer that bonds the polarizer to the resin layer. The bonding layer can be formed by an adhesive or binder. Examples of adhesives include UV-curable adhesives and other active energy radiation-curable adhesives, aqueous solutions of polyvinyl alcohol resins or aqueous solutions containing crosslinking agents, and urethane emulsion adhesives. When a thermoplastic resin film is bonded to both sides of the polarizer, the adhesives forming the two bonding layers can be of the same type or different types. For example, when a thermoplastic resin film is bonded to both sides, one side can be bonded using an aqueous adhesive, and the other side can be bonded using an active energy radiation-curable adhesive. UV-curable adhesives can be mixtures of free radical polymerizable (meth)acrylic compounds and photofree radical polymerization initiators, or mixtures of cationic polymerizable epoxy compounds and photocationic polymerization initiators. Alternatively, cationic polymerizable epoxy compounds and free radical polymerizable (meth)acrylic compounds can be used together, with both photocationic polymerization initiators and photofree radical polymerization initiators used as initiators. The thickness of the adhesive can be, for example, greater than 0.1 μm and less than 5 μm.

[0064] When using active energy radiation-curing adhesives, the adhesive is cured by irradiating it with active energy radiation after bonding. The source of the active energy radiation is not particularly limited, but active energy radiation (ultraviolet light) with a luminescence distribution at wavelengths below 400 nm is preferred. Specifically, low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, chemical lamps, black light lamps, microwave-excited mercury lamps, and metal halide lamps are preferred.

[0065] To improve the adhesion between the polarizer and the thermoplastic resin film, surface treatments such as corona treatment, flame treatment, plasma treatment, ultraviolet irradiation treatment, primer coating treatment, and saponification treatment can be applied to the bonding surfaces of at least one of the polarizer and the thermoplastic resin film before bonding.

[0066] When the bonding layer is formed by an adhesive, the thickness of the bonding layer can be, for example, 0.01 μm or more and 10 μm.

[0067] The adhesive used as the bonding layer can be, for example, a pressure-sensitive adhesive (hereinafter also referred to as an adhesive).

[0068] The adhesive can be composed of an adhesive composition with resins such as (meth)acrylic acid resins, rubber resins, urethane resins, ester resins, silicone resins, and polyvinyl ether resins as the main components. From the viewpoints of transparency, weather resistance, heat resistance, and storage modulus, an adhesive composition with (meth)acrylic acid resin as the base polymer is preferred. The adhesive composition can be either an active energy radiation-cured type or a thermosetting type.

[0069] The (meth)acrylic resin (base polymer) used in the adhesive composition is, for example, a polymer or copolymer with one or more (meth)acrylate monomers such as butyl (meth)acrylate, ethyl (meth)acrylate, isooctyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate. It is preferable to copolymerize the polar monomer with the base polymer. Examples of polar monomers include, for example, (meth)acrylic acid, 2-hydroxypropyl (meth)acrylate, hydroxyethyl (meth)acrylate, (meth)acrylamide, N,N-dimethylaminoethyl (meth)acrylate, and glycidyl (meth)acrylate, which have carboxyl, hydroxyl, amide, amino, or epoxy groups.

[0070] The adhesive composition may contain only the aforementioned base polymer, but typically also contains a crosslinking agent. Examples of crosslinking agents include crosslinking agents that are divalent or higher metal ions forming a carboxylic acid metal salt with a carboxyl group; crosslinking agents that are polyamine compounds forming an amide bond with a carboxyl group; crosslinking agents that are polyepoxide compounds or polyols forming an ester bond with a carboxyl group; and crosslinking agents that are polyisocyanate compounds forming an amide bond with a carboxyl group. Among these, polyisocyanate compounds are preferred.

[0071] In the case where the bonding layer is formed by an adhesive, for example, an adhesive liquid can be prepared by dissolving or dispersing the adhesive composition in an organic solvent such as toluene or ethyl acetate, and then directly applied to the bonding surface to form an adhesive layer; or an adhesive layer can be formed in sheet form on a diaphragm that has undergone a demolding treatment and then transferred to the bonding surface, etc.

[0072] The membrane can be a membrane containing polyethylene resins such as polyethylene, polypropylene resins such as polypropylene, polyester resins such as polyethylene terephthalate, etc. Among them, a stretch membrane of polyethylene terephthalate is preferred.

[0073] Adhesives can contain any components, such as glass fibers, glass beads, resin beads, fillers containing metal powder or other inorganic powders, pigments, colorants, antioxidants, ultraviolet absorbers, antistatic agents, etc.

[0074] Examples of antistatic agents include ionic compounds, conductive microparticles, and conductive polymers, with ionic compounds being preferred.

[0075] The cationic components that make up ionic compounds can be either inorganic or organic cations.

[0076] Examples of organic cations include pyridinium cations, imidazolium cations, ammonium cations, sulfonium cations, phosphonium cations, piperidinium cations, and pyrrolidineium cations. Examples of inorganic cations include lithium ions and potassium ions.

[0077] On the other hand, the anionic component constituting the ionic compound can be an inorganic anion or an organic anion. From the perspective of providing an ionic compound with excellent antistatic properties, anionic components containing fluorine atoms are preferred. Examples of anionic components containing fluorine atoms include hexafluorophosphate anion [(PF6]]. - )], Bis(trifluoromethanesulfonyl)imide anion [(CF3SO2)2N - [Anion, bis(fluorosulfonyl)imide anion [(FSO2)2N] - Anions, etc.

[0078] The thickness of the adhesive layer formed by the adhesive can be, for example, 30 μm or less, preferably 25 μm or less, and more preferably 20 μm or less. The thickness of the adhesive layer formed by the adhesive can be, for example, 1 μm or more, preferably 2 μm or more, and more preferably 3 μm or more.

[0079] To improve adhesion, surface treatments such as corona treatment, flame treatment, plasma treatment, ultraviolet irradiation treatment, primer coating treatment, and saponification treatment can be applied to the bonding surfaces.

[0080] [Adhesive layer]

[0081] The adhesive layer can function to bond the front-side polarizer 100 and the back-side polarizer 200 to the liquid crystal cell 300. As the adhesive constituting the adhesive layer, conventionally known adhesives can be used without particular limitation, such as those exemplified in the above-described bonding layer. Alternatively, it can be an active energy ray curable adhesive, a thermosetting adhesive, etc. The adhesive layer can have a diaphragm.

[0082] [Phase difference layer]

[0083] The front-side polarizer 100 and the back-side polarizer 200 may include a phase retardation layer between the polarizer and the liquid crystal cell. The phase retardation layer may be a single layer or a stack of phase retardation layers containing two or more phase retardation layers. The phase retardation layer may be stacked on the polarizer or linear polarizer using the aforementioned bonding layer.

[0084] As a phase retardation layer, it can be a positive A layer or a positive C layer, such as a λ / 4 layer or a λ / 2 layer. The phase retardation layer can be formed from a liquid crystal cured layer containing a polymeric liquid crystal compound, or from a resin film exemplified as a material of the aforementioned thermoplastic resin film. The film-like phase retardation layer 130 may further include an alignment layer and a substrate.

[0085] The phase retardation layer preferably includes a λ / 4 layer, more preferably a λ / 4 layer, and at least one of a λ / 2 layer and a positive C layer. When the phase retardation layer includes a λ / 2 layer, it can be stacked such that the λ / 2 layer and the λ / 4 layer are stacked sequentially from the polarizer side. When the phase retardation layer includes a positive C layer, it can be stacked such that the λ / 4 layer and the positive C layer are stacked sequentially from the polarizer side, or it can be stacked such that the positive C layer and the λ / 4 layer are stacked sequentially from the polarizer side.

[0086] The thickness of the phase retardation layer can be, for example, 0.1 μm or more and 50 μm or less, preferably 1 μm or more and 30 μm or less, and more preferably 0.5 μm or more and 15 μm or less.

[0087] [Protective film]

[0088] The front-side polarizer 100 and the back-side polarizer 200 may also have protective films on the side opposite to the liquid crystal cell 300. The protective film may be peeled off along with its adhesive layer after the polarizer is attached to the liquid crystal cell or other optical components.

[0089] The protective film, for example, consists of a substrate film and an adhesive layer laminated thereon. Regarding the adhesive layer, the description of the bonding layer described above applies. The resin constituting the substrate film can be, for example, a polyethylene-based resin such as polyethylene, a polypropylene-based resin such as polypropylene, a polyester-based resin such as polyethylene terephthalate or polyethylene naphthalate, or a thermoplastic resin such as polycarbonate. A polyester-based resin such as polyethylene terephthalate is preferred.

[0090] The thickness of the protective film is not particularly limited, but is preferably set to a range of 20 μm or more and 200 μm or less. If the thickness of the substrate is 20 μm or more, there is a tendency to easily impart strength to the front polarizer 100 and the back polarizer 200.

[0091] [Layer Structure of Polarizing Plate Assembly]

[0092] Reference Figure 2 One embodiment of the polarizing plate assembly of the present invention will be described. Figure 2 The polarizing plate assembly 2 shown comprises a front-side polarizing plate 101 disposed on the observation side of the liquid crystal cell 300 and a back-side polarizing plate 201 disposed on the back side of the liquid crystal cell 300. The front-side polarizing plate 101 and the back-side polarizing plate 201 respectively include polarizers 130 and 230. The front-side polarizing plate 101 further includes a resin layer 110, a low-humidity-permeability resin layer 150, bonding layers 120 and 140, and an adhesive layer 160. Additionally, as... Figure 1 As shown, the back polarizing plate 201 also includes a resin layer 210, a low moisture permeability resin layer 250, bonding layers 220 and 240, and an adhesive layer 260.

[0093] [Manufacturing method of polarizing plate]

[0094] The front-side polarizer and the back-side polarizer can be manufactured, for example, by bonding the layers together using an adhesive layer. In the case of bonding, to improve the adhesion, it is preferable to perform a surface activation treatment, such as corona treatment, on one or both of the bonding surfaces.

[0095] The adhesive layer can be prepared in the form of an adhesive sheet. The adhesive sheet can be made, for example, by dissolving or dispersing an adhesive composition in an organic solvent such as toluene or ethyl acetate to prepare an adhesive liquid, forming a sheet-like layer containing the adhesive on a release film that has undergone a demolding treatment, and further bonding other release films onto this adhesive layer. The layers can be bonded by bonding an adhesive sheet with one release film peeled off to a layer (e.g., a polarizing plate), then peeling off another release film, and bonding another layer (e.g., a liquid crystal cell).

[0096] As a method for applying adhesive liquid to the release film, conventional coating techniques using mold coating machines, comma coating machines, reverse roller coating machines, gravure coating machines, bar coating machines, wire bar coating machines, doctor blade coating machines, air knife coating machines, etc., are acceptable.

[0097] The release film is preferably composed of a plastic film and a release layer. Examples of plastic films include polyester films such as polyethylene terephthalate films, polybutylene terephthalate films, and polyethylene naphthalate films, and polyolefin films such as polypropylene films. The release layer can be formed, for example, from a release layer forming composition. The main component (resin) constituting the release layer forming composition is not particularly limited, and examples include silicone resins, alkyd resins, acrylic resins, and long-chain alkyl resins.

[0098] [Liquid Crystal Unit]

[0099] A liquid crystal cell has two cell substrates and a liquid crystal layer sandwiched between these substrates. The cell substrates are typically made of glass, but can also be plastic substrates. Furthermore, the liquid crystal cells used in the liquid crystal panel of this invention can themselves be composed of various cells employed in the art (e.g., cells known as IPS, VA, TN, etc., as driving modes).

[0100] [LCD panel]

[0101] LCD panels can be manufactured by attaching polarizing plates to liquid crystal cells using an adhesive layer.

[0102] Example

[0103] The present invention will be further described in detail below through examples. Unless otherwise specified, "%" and "parts" in the examples refer to mass % and mass parts.

[0104] [Thickness Measurement]

[0105] Measurements were performed using a digital micrometer (MH-15M, manufactured by Nikon Corporation).

[0106] [Determination of warpage]

[0107] Two polarizing plates prepared in the examples and comparative examples were bonded to a glass unit to obtain a glass panel. The panel was placed at a temperature of 25°C and a humidity of 90% for 72 hours, and then at room temperature for 1 hour. Additionally, it was placed at a temperature of 40°C and a humidity of 55% for 24 hours.

[0108] With the front polarizer facing up, place the glass panel on the measuring stage of a two-dimensional measuring instrument (NEXIV VMR-12072, manufactured by Nikon Corporation). Next, align the focal point with the surface of the measuring stage. Using this as a reference, align the focal point with the four corners, the center of each of the four sides, and the center of the glass panel surface. After measuring the distance from the focal point used as the reference, determine the longest distance from the measuring stage in absolute terms. Warpage at the edge of the observation side panel of the glass panel is defined as positive warpage, and warpage at the edge of the back side panel is defined as negative warpage. For both the example and the comparative example, two measuring samples were prepared for measurement, and the average of the longest distances mentioned above was determined as the warpage amount.

[0109] [Measurement of moisture permeability]

[0110] For low moisture permeability resin layers, a constant temperature and humidity bath is used. Under the conditions of 40℃ temperature, 90%RH relative humidity, and 24-hour measurement time, the water vapor transmission rate is determined by the moisture permeability test method (cup method, according to JIS Z 0208) and used as the moisture permeability.

[0111] <Example 1>

[0112] A 30 μm thick polyvinyl alcohol film (average degree of polymerization approximately 2400, degree of saponification ≥ 99.9 mol%) was uniaxially stretched approximately 5 times in length using a dry stretching method. Then, while maintaining tension, it was immersed in pure water at 60°C for 1 minute, followed by immersion in an aqueous solution at 28°C with an iodine / potassium iodide / water weight ratio of 0.05 / 5 / 100 for 60 seconds. Next, it was immersed in an aqueous solution at 72°C with a potassium iodide / boric acid / water weight ratio of 8.5 / 8.5 / 100 for 300 seconds. Finally, it was washed with pure water at 26°C for 20 seconds and dried at 65°C to obtain a 12 μm thick polarizer with iodine adsorption oriented onto the polyvinyl alcohol film.

[0113] Next, the following aqueous adhesive was applied to both sides of the polarizer with a thickness of 2 μm: 3 parts by weight of carboxyl-modified polyvinyl alcohol (KL-318 manufactured by Kuraray Co., Ltd.) were dissolved in water to prepare an aqueous solution. Water-soluble polyamide epoxy resin (Sumirez manufactured by Sumitomo Chemical Co., Ltd.) was then mixed into the prepared aqueous solution at a ratio of 1.5 parts by weight to 100 parts by weight of water. A water-based adhesive, consisting of Resin (registered trademark) 650 (30) with a solid content of 30% by weight, was applied to a 25 μm thick triacetyl cellulose membrane (trade name "KC2UA" manufactured by Konica Minolta Co., Ltd.) (hereinafter also referred to as TAC) as a resin layer. On the other side, a 13 μm thick cyclic olefin resin membrane (trade name "ZEONOR (registered trademark)" manufactured by ZEON Co., Ltd. of Japan, with an in-plane phase difference Re = 0.8 nm at a wavelength of 590 nm) (hereinafter also referred to as COP) was applied to the COP side. Then, a 5 μm thick adhesive (an adhesive layer containing an acrylic adhesive, manufactured by Lintec Co., Ltd.) was applied to the COP side to obtain a linear polarizer consisting of a TAC / adhesive layer / polarizer / adhesive layer / COP / adhesive layer.

[0114] Cut out the front and back side polarizers from the fabricated polarizer, and fabricate the glass panel as follows. First, cut the front side polarizer to a size of 130mm (absorption axis direction) × 90mm (transmission axis direction) and the back side polarizer to a size of 90mm (absorption axis direction) × 130mm (transmission axis direction). Then, cut the front side polarizer to a diagonal 7-inch size with the absorption axis of the front side polarizer parallel to the short side of the glass unit and the absorption axis of the back side polarizer parallel to the long side of the glass unit, thus obtaining the polarizer assembly.

[0115] The cut polarizing plates were bonded to the glass unit with their short sides parallel to the short side of the glass unit using an adhesive layer. The thickness of the glass unit used was 0.4 mm. L1 and L2 were both 20 μm. The warpage of the resulting glass panel was measured. The results are shown in Table 1.

[0116] <Comparative Example 1>

[0117] The adhesive layer used in Example 1 was changed to a thickness of 25 μm. Otherwise, the polarizing plate assembly was fabricated in the same manner as in Example 1. L1 and L2 were both 40 μm. The results are shown in Table 1.

[0118] [Table 1]

[0119]

[0120] Explanation of reference numerals in the attached figures

[0121] 1, 2: Polarizing plate assembly; 100: Front-side polarizing plate; 110, 210: Resin layer; 120, 220: Adhesive layer; 130, 230: Polarizing film; 140, 240: Adhesive layer; 150, 250: Low moisture permeability resin layer; 160, 260: Adhesive layer; 200: Back-side polarizing plate; 300: Liquid crystal unit; L1, L2: Distance

Claims

1. A polarizing plate assembly comprising a front-side polarizing plate disposed on the viewing side of a liquid crystal cell and a back-side polarizing plate disposed on the back side of the liquid crystal cell. The front-side polarizing plate and the back-side polarizing plate include polarizing filters. When the distance from the surface of the polarizer included in the front polarizer to the surface of the liquid crystal cell on the front polarizer is defined as L1, and the distance from the surface of the polarizer included in the back polarizer to the surface of the liquid crystal cell on the back polarizer is defined as L2, both L1 and L2 are 20 μm or less. The units for L1 and L2 are μm. At least one of the front-side polarizer and the back-side polarizer has a permeability of 400 g / m³ at a temperature of 40°C and a humidity of 90% RH on the liquid crystal cell side of the polarizer. 2 • Resin layers less than 24 hours The front polarizer and the back polarizer are square in shape with a long side and a short side. The absorption axis of the front polarizer is parallel to the short side, and the absorption axis of the back polarizer is parallel to the long side.

2. A polarizing plate assembly comprising a front-side polarizing plate disposed on the viewing side of a liquid crystal cell and a back-side polarizing plate disposed on the back side of the liquid crystal cell. The front-side polarizing plate and the back-side polarizing plate include polarizing filters. When the distance from the surface of the polarizer included in the front polarizer to the surface of the liquid crystal cell on the front polarizer is defined as L1, and the distance from the surface of the polarizer included in the back polarizer to the surface of the liquid crystal cell on the back polarizer is defined as L2, both L1 and L2 are 20 μm or less. The units for L1 and L2 are μm. At least one of the front-side polarizer and the back-side polarizer has a permeability of 400 g / m³ at a temperature of 40°C and a humidity of 90% RH on the liquid crystal cell side of the polarizer. 2 • Resin layers less than 24 hours The front polarizer and the back polarizer are square in shape with a long side and a short side. The absorption axis of the front polarizer is parallel to the long side, and the absorption axis of the back polarizer is parallel to the short side.

3. The polarizing plate assembly according to claim 1 or 2, wherein, The sum of L1 and L2 is less than 40 μm, where the units of L1 and L2 are μm.

4. The polarizing plate assembly according to claim 1 or 2, wherein, The absolute value of the difference between L1 and L2 is less than 3 μm, where the units of L1 and L2 are μm.

5. The polarizing plate assembly according to claim 1 or 2, wherein, The polarizers contained in the front polarizer and the back polarizer have substantially the same thickness.

6. The polarizing plate assembly according to claim 1 or 2, wherein, Both the front-side polarizer and the back-side polarizer have a permeability of 400 g / m³ at a temperature of 40°C and a humidity of 90% RH on the side of the polarizer's liquid crystal cell. 2 • Resin layer for less than 24 hours.

7. The polarizing plate assembly according to claim 1 or 2, wherein, Both the front-side polarizer and the back-side polarizer contain a cyclic olefin resin film on the liquid crystal cell side of the polarizer.

8. The polarizing plate assembly according to claim 1 or 2, wherein, Both the front-side polarizer and the back-side polarizer contain a triacetyl cellulose resin film on the side of the polarizer opposite to the liquid crystal cell.

9. A liquid crystal panel comprising a polarizing plate assembly and a liquid crystal cell as described in any one of claims 1 to 8.

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