JP2011033970A - Polarizing plate, method for producing the same, and projection liquid crystal display device - Google Patents

Abstract

A polarizing plate excellent in light resistance and heat resistance capable of sufficiently suppressing deterioration of a polarizer and peeling of the polarizer even when exposed to high-luminance light and a high temperature associated therewith. In addition, the present invention provides a polarizing plate capable of sufficiently suppressing deterioration in image quality of a projected image of an applied liquid crystal display device, a manufacturing method thereof, and a projection type liquid crystal display device using the same.
A polarizer, a single crystal substrate laminated on one surface of the polarizer via a first adhesive layer, and a second adhesive layer on the other surface of the polarizer. A polarizing plate comprising a laminated amorphous substrate, the side surface of the polarizer being coated with a sealing agent, a linear thermal expansion coefficient in a direction parallel to the C axis of the single crystal substrate, and an amorphous A polarizing plate having an absolute value of a difference from the linear thermal expansion coefficient of the conductive substrate of 30 × 10 ⁻⁷ / ° C. or less and having a glass transition temperature different between the first adhesive layer and the second adhesive layer, and A manufacturing method and a projection type liquid crystal display device using the same.
[Selection] Figure 1

Description

  The present invention relates to a polarizing plate suitably used for a projection-type liquid crystal display device such as a front projector and a rear projector, and a method for manufacturing the same. The present invention also relates to a projection type liquid crystal display device using the polarizing plate.

  In order to cope with an increase in screen size, a projection type liquid crystal display device is rapidly spreading for business use and home use instead of a conventional cathode ray tube type display device. In the projection type, after separating the light from the light source into the three primary colors of RGB, each light is passed through a liquid crystal cell, a polarizing plate, etc. in each optical path, and finally enlarged by a projection lens on the screen. This is a method of forming an image and displaying an image. Projection-type liquid crystal display devices are mainly used for business purposes, with front projectors that project images on the front side of the screen when viewed from the viewer's side, and rear projectors that project images on the back side of the screen. It is used as.

  In recent years, projection-type liquid crystal display devices have increased in screen brightness, and accordingly, high-pressure mercury lamps that emit powerful light have come to be used as light sources. For this reason, the polarizing plate installed in the optical path becomes high temperature due to irradiation of high-intensity light, and the deterioration of the polarizer and the distortion of the screen due to the peeling of the polarizer occur, resulting in a decrease in the contrast and the image quality of the projected image. Problem is likely to occur.

  Thus, for example, in Patent Document 1, as shown in FIG. 8, there is a technique for improving the durability of a polarizing plate by attaching glass plates 801 and 802 to both surfaces of a polarizing film 803 via an adhesive layer 804. Proposed. Patent Document 2 proposes a technique of preventing the polarizer from absorbing moisture and suppressing the deterioration of the polarizer by enclosing the polarizer with a glass and a sealing agent having high thermal conductivity.

Japanese Patent Laid-Open No. 10-39138 JP 2008-268842 A

  Currently, an increase in light intensity of a light source is required for a projection type liquid crystal display device. Under such circumstances, the polarizing plate is further required to further improve the light resistance and heat resistance and to suppress the deterioration of the image quality of the projected image.

  Therefore, an object of the present invention is to provide light resistance and heat resistance, which can sufficiently suppress the deterioration of the polarizer and the peeling of the polarizer even when exposed to high-luminance light and the accompanying high temperature. It is an excellent polarizing plate, and a polarizing plate capable of sufficiently suppressing deterioration in image quality of a projected image of an applied liquid crystal display device and a method for manufacturing the same. Another object of the present invention is to provide a projection type liquid crystal display device using the polarizing plate.

The present invention includes a polarizer, a single crystal substrate laminated on one surface of the polarizer via a first adhesive layer, and a second adhesive layer on the other surface of the polarizer. A polarizing plate comprising a laminated amorphous substrate, the side surface of the polarizer being coated with a sealing agent, a linear thermal expansion coefficient in a direction parallel to the C axis of the single crystal substrate, and an amorphous Provided is a polarizing plate having an absolute value of a difference from a linear thermal expansion coefficient of a conductive substrate of 30 × 10 ⁻⁷ / ° C. or less and having a glass transition temperature different between a first adhesive layer and a second adhesive layer. To do.

  In the present invention, the difference between the glass transition temperature of the first adhesive layer and the glass transition temperature of the second adhesive layer is preferably 60 ° C. or higher. One of the first adhesive layer and the second adhesive layer is a layer formed from a pressure-sensitive adhesive, and the other is a layer formed from a thermosetting adhesive or an ultraviolet curable adhesive. It is preferable.

  Preferred examples of the single crystal substrate include a substrate made of quartz and a substrate made of sapphire. The thermal conductivity of the single crystal substrate is preferably 5 W / mK or more.

  The moisture content of the polarizer is preferably 5% by weight or less. Preferred examples of the polarizer include a polarizer obtained by adsorbing and orienting a dichroic dye or iodine on a film made of a polyvinyl alcohol resin, and a polarizer made of a polyvinyl alcohol / polyvinylene block copolymer.

  The polarizing plate of the present invention may further include a retardation film laminated on the surface opposite to the polarizer in the single crystal substrate and / or the amorphous substrate.

  The present invention also provides a method for producing a polarizing plate according to the present invention, comprising: forming a first adhesive layer on one surface of a polarizer and / or one surface of a single crystal substrate; A step of forming a second adhesive layer on the other surface and / or one surface of the amorphous substrate; and a single crystal substrate, a first adhesive layer, a polarizer, a second adhesive layer, and an amorphous substrate There is provided a method for producing a polarizing plate, comprising: a step of obtaining a laminate in which substrates are laminated in this order; and a step of covering a side surface of a polarizer with a sealant.

  In the manufacturing method of the polarizing plate of this invention, it is preferable that formation of a 1st adhesive bond layer and a 2nd adhesive bond layer is performed under reduced pressure. Moreover, it is preferable that the manufacturing method of the polarizing plate of this invention is further equipped with the process of drying a polarizer at the temperature of 130 degrees C or less.

  Furthermore, the present invention provides a projection type liquid crystal display device comprising a liquid crystal cell and the polarizing plate of the present invention disposed on at least one surface of the liquid crystal cell. In the projection-type liquid crystal display device of the present invention, the polarizing plate is preferably arranged so that the amorphous substrate side faces the liquid crystal cell.

  According to the polarizing plate of the present invention, deterioration of the polarizer and peeling of the polarizer can be sufficiently suppressed even when exposed to high-intensity light and a high temperature associated therewith. Degradation of the image quality of the projected image of the apparatus can be sufficiently suppressed. Since the projection-type liquid crystal display device of the present invention uses a polarizing plate that is excellent in light resistance and heat resistance, it has a long life and is excellent in image quality.

It is a schematic sectional drawing which shows a preferable example of the polarizing plate of this invention. It is a schematic sectional drawing which shows another preferable example of the polarizing plate of this invention. It is a schematic sectional drawing which shows another preferable example of the polarizing plate of this invention. It is a schematic sectional drawing which shows another preferable example of the polarizing plate of this invention. It is a schematic sectional drawing which shows another preferable example of the polarizing plate of this invention. It is a figure which shows typically an example of the projection type liquid crystal display device of this invention. It is a figure which shows typically the structure of a light resistance evaluation apparatus. It is a schematic sectional drawing which shows an example of the conventional polarizing plate.

<Polarizing plate>
FIG. 1 is a schematic cross-sectional view showing a preferred example of the polarizing plate of the present invention. As shown in FIG. 1, the polarizing plate of the present invention includes a polarizer 3, a single crystal substrate 1 laminated on one surface of the polarizer 3 via a first adhesive layer 4, and a polarizer 3. And the amorphous substrate 2 laminated on the other surface via the second adhesive layer 5. The side surfaces of the polarizer 3 that are not covered with the single crystal substrate 1 and the amorphous substrate 2 are covered with a sealant 7. Hereinafter, the polarizing plate of the present invention will be described more specifically.

(Polarizer)
As the polarizer 3, for example, a polarizer in which a dichroic dye or iodine is adsorbed and oriented on a resin film such as polyvinyl alcohol resin, polyvinyl acetate resin, ethylene / vinyl acetate (EVA) resin, polyamide resin, or polyester resin. Alternatively, a polarizer made of polyvinyl alcohol / polyvinylene block copolymer can be used. The latter polyvinyl alcohol / polyvinylene block copolymer polarizer is a polyvinyl alcohol film that is molecularly oriented by stretching, etc., exposed to concentrated hydrochloric acid or concentrated sulfuric acid, etc., partially dehydrated, and two colors of polyvinyl alcohol Conjugated dehydration product, a conjugated block of polyvinylene. The copolymer may be used as a polarizer as it is, but usually a material impregnated with boric acid and / or borax is used as the polarizer.

  Among these, a polarizer in which a dichroic dye or iodine is adsorbed and oriented on a polyvinyl alcohol-based resin film is preferably used.

  The polyvinyl alcohol-based resin includes polyvinyl alcohol which is a part of polyvinyl acetate or a completely saponified product; vinyl acetate and other copolymerizable monomers such as saponified EVA resin (for example, ethylene and propylene Olefins, saponified products of copolymers with unsaturated carboxylic acids such as crotonic acid, acrylic acid, methacrylic acid, maleic acid, unsaturated sulfonic acids, vinyl ethers, etc .; polyvinyl formal obtained by modifying polyvinyl alcohol with aldehyde, Polyvinyl acetal and the like are included. A polyvinyl alcohol-based resin film, particularly a resin film made of polyvinyl alcohol, is preferably used from the viewpoints of dichroic dye or iodine adsorption and orientation.

  In the polarizing plate of the present invention, a dichroic dye is more preferably used as being adsorbed and oriented on the polyvinyl alcohol resin film. By selecting dichroic dyes having different wavelength dependencies, polarizers suitable for blue channel polarizing plates, green channel polarizing plates, and red channel polarizing plates of projection type liquid crystal display devices can be respectively produced. it can.

  Examples of the dichroic dye include compounds described in “Development of dichroic dyes for liquid crystal display devices” (Sone et al., Sumitomo Chemical, 2002-II, pages 23 to 30). Includes the following dichroic dyes.

  (A) Formula (I):

(In the formula, Me represents a metal atom selected from a copper atom, a nickel atom, a zinc atom and an iron atom. A ¹ represents an optionally substituted phenyl group or an optionally substituted naphthyl group. B ¹ Represents an optionally substituted naphthyl group, and the oxygen atom bonded to Me and the azo group represented by -N = N- are carbons adjacent to each other on the benzene ring constituting the naphthyl group. R ¹ and R ² are each independently an alkyl group having 1 to 4 carbon atoms, an alkoxyl group having 1 to 4 carbon atoms, a carboxyl group, a sulfoxy group, a sulfonamide group, a sulfone alkylamide group, an amino group Group, acylamino group, halogen atom or nitro group.)
A dichroic dye represented by

  (B) Formula (II) in the form of the free acid:

(In the formula, A ³ and B ³ each independently represent an optionally substituted phenyl group or an optionally substituted naphthyl group, and R ³ and R ⁴ each independently represent a hydrogen atom, a carbon number of 1 An alkyl group of ˜4, an alkoxyl group of 1 to 4 carbon atoms, a carboxyl group, a sulfoxy group, a sulfonamide group, a sulfonealkylamide group, an amino group, a halogen atom or a nitro group, and m is 0 or 1.
A dichroic dye represented by

(C) Formula (III):
^{Q 1 -N = N-Q 2} -X-Q 3 -N = N-Q 4 (III)
(Wherein Q ¹ and Q ⁴ each independently represents an optionally substituted phenyl group or an optionally substituted naphthyl group, and X represents the following formula (III-1):
-N = N- (III-1)
Or following formula (III-2):

The bivalent residue shown by is shown. Q ² and Q ³ each independently represents an optionally substituted phenylene group. ]
The dichroic dye shown by these is mentioned.

  (D) Formula (IV):

(In the formula, Me represents a metal atom selected from a copper atom, a nickel atom, a zinc atom and an iron atom, Q ⁵ and Q ⁶ each independently represents a naphthyl group which may have a substituent, Me The oxygen atom bonded to the azo group and the azo group represented by -N = N- are bonded to carbons adjacent to each other on the benzene ring constituting the naphthyl group, Y is represented by the following formula (IV- 1):
-N = N- (IV-1)
Or following formula (IV-2):

The bivalent residue shown by is shown. R ⁵ and R ⁶ each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxyl group having 1 to 4 carbon atoms or a sulfoxy group. )
A dichroic dye represented by

  Other dichroic dyes other than the above include C-I Direct Yellow 12, C-I Direct Red 31, C-I Direct Red 28, C-I Direct Yellow 44, C.I. Eye Direct Yellow 28, Sea Eye Direct Orange 107, Sea Eye Direct Red 79, Sea Eye Direct Red 2, Sea Eye Direct Red 81, Sea Eye Direct Orange 26, dichroic dyes having color index generic names such as C.I.Direct Orange 39, C.I.Direct Red 247 and C.I.Direct Yellow 142 Is exemplified.

  The dichroic dye may be used in the form of a free acid, or may be used in the form of an amine salt such as an ammonium salt, an ethanolamine salt, or an alkylamine salt. Usually, a lithium salt, a sodium salt, Used in the form of alkali metal salts such as potassium salts. In preparing the polarizer, only one dichroic dye may be used alone, or two or more dichroic dyes may be used in combination.

  The polarizer is manufactured, for example, as follows. First, a dichroic dye is dissolved in water so as to have a concentration of about 0.0001 to 10% by weight to prepare a dye bath. If necessary, a dyeing assistant may be used. For example, it is preferable to dissolve 0.1 to 10% by weight of mirabilite as a dyeing assistant in a dyeing bath.

  Dyeing is performed by immersing a polarizer substrate such as a polyvinyl alcohol-based resin film in the dye bath thus prepared. A preferred dyeing temperature is 40-80 ° C. The dye is oriented prior to dyeing or by stretching the dyed polarizer substrate. Examples of the stretching method include a stretching method by a wet method or a dry method.

  For the purpose of improving the light transmittance, polarization degree, and light resistance of the polarizer, post-treatment such as boric acid treatment may be performed. The boric acid treatment varies depending on the type of polarizer substrate used and the type of dye used, but usually with an aqueous boric acid solution prepared at a concentration in the range of 1 to 15% by weight, preferably 5 to 10% by weight. 30 to 80 ° C., preferably 50 to 80 ° C., by immersing the polarizer substrate. If necessary, the fixing treatment may be performed together with an aqueous solution containing a cationic polymer compound.

  The water content of the polarizer 3 used in the present invention is preferably 5% by weight or less, more preferably 1% by weight or less. In the polarizer formed by adsorbing and orienting the dichroic dye on the polyvinyl alcohol-based resin film, the decomposition of the dichroic dye can be more effectively suppressed by setting the water content to 5% by weight or less. The light resistance of the obtained polarizing plate can be greatly improved.

The water content of the polarizer 3 is measured by air-drying the polarizer at 130 ° C. for 20 minutes in a state where at least one surface thereof is not coated, and determining the proportion of the weight loss of the polarizer. That is, the following formula:
Water content of polarizer (%) = [(W1-W2) / W1] × 100
(W1 is the weight before drying of the polarizer, and W2 is the weight after drying of the polarizer.)
From the above, the water content of the polarizer is calculated.

  Adjustment of the moisture content of the polarizer 3 can be performed by drying the polarizer. As will be described later, the drying process for adjusting the moisture content of the polarizer 3 to 5% by weight or less is performed at a stage where the single crystal substrate 1 and the amorphous substrate 2 are not bonded to the polarizer 3 at all. Alternatively, it may be performed at a stage after the single crystal substrate 1 and / or the amorphous substrate 2 are bonded to the polarizer 3, but one of the single crystal substrate 1 and the amorphous substrate 2 is provided on one side. It is preferable to dry at the stage of being bonded to the substrate because the flatness of the polarizer can be maintained, and moisture removal from the surface where the substrate of the polarizer 3 is not bonded is performed quickly. Further, in this case, there is an advantage that moisture does not enter from the substrate side after drying, and it is easy to maintain the dried state of the polarizer. In addition, when the substrate is bonded to one surface of the polarizer 3 and dried, and the substrate is bonded to the other surface of the polarizer and then dried again, the polarizer can be further dried. preferable.

  As the drying method, a conventionally known method can be used, and examples thereof include a heat drying method and a vacuum drying method. The heat drying method is preferable from the viewpoint of simplicity of production equipment for the polarizing plate. Examples of the heat drying method include a method of putting in a heating oven, a method of irradiating light to the polarizer, and utilizing the heat generated by the polarizer itself by absorption of the light of the polarizer. The heating temperature in the heat drying method is preferably 130 ° C. or less, more preferably 40 ° C. to 130 ° C., regardless of the heating method. By setting the temperature to 40 ° C. or higher, drying can be completed in a relatively short time. By setting the temperature to 130 ° C. or lower, deterioration of the adhesive layer and deterioration of the optical characteristics of the polarizer can be suppressed.

(Single crystal substrate and amorphous substrate)
The absolute value of the difference between the linear thermal expansion coefficient in the direction parallel to the C axis of the single crystal substrate 1 used in the present invention and the linear thermal expansion coefficient of the amorphous substrate 2 is 30 × 10 ⁻⁷ / ° C. or less. Preferably, it is 20 × 10 ⁻⁷ / ° C. or less. If the absolute value of the difference between the linear thermal expansion coefficients is 30 × 10 ⁻⁷ / ° C. or less, the single crystal substrate 1 and the amorphous substrate 2 expand to the same extent under high temperature conditions, so that the polarization plate is deformed. Since the stress acting between the polarizer and the substrate is reduced, peeling between the polarizer and the substrate can be suppressed, and a polarizing plate having excellent heat resistance can be obtained. Here, the linear thermal expansion coefficient is a value measured in accordance with JIS R1618, and is a value measured in the range of 0 ° C to 300 ° C.

Examples of the material of the single crystal substrate 1 used in the present invention include quartz, sapphire, spinel (MgO.Al ₂ O ₃ ), YAG crystal, and fluorite. Among these, those having a thermal conductivity of 5 W / mK or more are preferable from the viewpoint of efficiently radiating heat generated in the polarizer 3 to the outside and lowering the temperature of the polarizer 3 to further improve the light resistance of the polarizing plate. . Examples of such a material include quartz and sapphire.

  The thickness of the single crystal substrate 1 is preferably 0.05 to 3 mm, more preferably from the viewpoint of yield in the case of industrialization and size matching with an optical system of a projection type liquid crystal display device (projector) to be applied. 0.08 to 2 mm. When the thickness of the single crystal substrate 1 is 0.05 mm or more, breakage during processing is suppressed and stable production can be achieved. Moreover, the polarizing plate obtained can be reduced in size and weight as the thickness of the single crystal substrate 1 is 3 mm or less.

The material of the amorphous substrate 2 used in the present invention is not particularly limited as long as the absolute value of the difference in linear thermal expansion coefficient from the single crystal substrate 1 is 30 × 10 ⁻⁷ / ° C. or less. In the case of using a quartz crystal substrate (linear thermal expansion coefficient 71 × 10 ⁻⁷ / ° C. parallel to the z axis (C axis)) often used as a polarizing plate for a projection type liquid crystal display device as the substrate 1, the amorphous substrate 2 as is the linear thermal expansion coefficient is used those in the range of 41~101 × 10 ^-7 / ℃, those in the range of 51~91 × 10 ^-7 / ℃ preferably used.

Specific examples of the material of the amorphous substrate 2 include, for example, quartz glass, silicate glass, soda lime glass, borosilicate glass, titanium silicate glass, zinc borosilicate glass, blue plate glass, white plate glass, lead Examples thereof include glass, alkali / barium / strontium glass, aluminoborosilicate glass, and borosilicate glass. Of these, blue plate glass and zinc borosilicate glass are preferably used because they have a linear thermal expansion coefficient in the range of 51 to 91 × 10 ⁻⁷ / ° C.

  The amorphous substrate 2 used in the present invention is preferably an unpolished product. Examples of such a substrate include an amorphous substrate manufactured by a Corning fusion method or a Schott downdraw method. Since the thickness of the substrate can be controlled without polishing the amorphous substrate produced by these manufacturing methods, it is preferably used as the amorphous substrate 2 of the present invention.

  The thickness of the amorphous substrate 2 used in the present invention is preferably 0.05 to 3 mm from the viewpoint of yield in the case of industrialization and size matching with an optical system of a projection type liquid crystal display device (projector) to be applied. . Moreover, it is more preferable that the thickness of the amorphous substrate 2 is in the range of 0.1 to 0.3 mm because the heat resistance of the polarizing plate is improved and the contrast of the projection screen is improved.

  At least one of the single crystal substrate 1 and the amorphous substrate 2 preferably has a front phase difference of less than 5 nm in a wavelength range of 380 nm to 780 nm. When the front phase difference of at least one of these transparent substrates is less than 5 nm, the light from the light source passes through the transparent substrate without distortion of the plane of polarized light generated by passing through the polarizer. Thereby, the contrast of the projection screen when applied to the projection type liquid crystal display device can be improved. Examples of the material of the single crystal substrate 1 having such characteristics include spinel, and examples of the material of the amorphous substrate 2 include quartz glass, silicate glass, soda lime glass, borosilicate glass, and titanium silicate glass. Examples thereof include zinc borosilicate glass, blue plate glass, white plate glass, lead glass, alkali / barium / strontium glass, aluminoborosilicate glass, and borosilicate glass.

  Here, the “front phase difference” means that the direction in which the refractive index in the substrate surface is maximum is the X axis, the direction perpendicular to the X axis is the Y axis, and the thickness direction of the substrate is the Z axis. It is a numerical value calculated by (nx1−ny1) × d1 where the refractive index is nx1, ny1, nz1 and the thickness of the substrate is d1 (nm).

  It is desirable to apply an antireflection treatment according to the wavelength of light to be used on the outer surface (surface opposite to the polarizer side) in contact with air in the single crystal substrate 1 and the amorphous substrate 2. Examples of the antireflection treatment include a method by forming a dielectric multilayer film by a sputtering method or a vacuum deposition method, and a method by providing one or more low refractive index layers by coating. Further, the antireflection surface may be provided with an antifouling treatment for preventing dirt from adhering to the surface. Examples of the antifouling treatment include forming on the surface a thin film layer containing fluorine that hardly affects the antireflection performance.

(First and second adhesive layers)
Different glass transition temperatures are used for the first adhesive layer 4 for bonding the single crystal substrate 1 to the polarizer 3 and the second adhesive layer 5 for bonding the amorphous substrate 2 to the polarizer 3. Have. Thereby, even if stress distortion occurs inside the polarizing plate due to heat generated when strong light is transmitted, the first adhesive layer 4 formed on both surfaces of the polarizer 3 and having different glass transition temperatures and the first adhesive layer 4 The adhesive layer 5 of 2 can absorb and relieve stress strain and effectively suppress problems such as peeling of the polarizer 3, and a polarizing plate having excellent heat resistance can be obtained. Note that the first adhesive layer 4 and the second adhesive layer 5 are usually transparent.

  The difference between the glass transition temperature of the first adhesive layer 4 and the glass transition temperature of the second adhesive layer 5 is preferably 60 ° C. or higher. At this time, the glass transition temperature of one adhesive layer is in the range of −80 ° C. to −10 ° C., more preferably in the range of −70 ° C. to −30 ° C., and the glass transition temperature of the other adhesive layer is 50 ° C. to It is preferable that the temperature be in the range of 200 ° C, more preferably in the range of 80 ° C to 120 ° C. Here, the glass transition temperature is a value measured according to JIS C6481.

  Specific examples of the adhesive that forms an adhesive layer having a glass transition temperature of −80 ° C. to −10 ° C. (hereinafter sometimes referred to as adhesive A) include low-elasticity adhesives (for example, silicone rubber, acrylic rubber). And pressure-sensitive adhesives (pressure-sensitive adhesives such as acrylic pressure-sensitive adhesives).

  Specific examples of an adhesive (hereinafter, sometimes referred to as an adhesive B) that forms an adhesive layer having a glass transition temperature of 50 ° C. to 200 ° C. include an epoxy resin adhesive (for example, thermosetting by Cemedine Co., Ltd.). Epoxy resins EP582), thermosetting adhesives such as urethane resin adhesives, phenol resin adhesives, etc .; UV curable epoxy resins (for example, UV curable epoxy resin KR695A manufactured by ADEKA), silicone resins (for example, UV curable) UV-curable adhesives such as type silicone, modified silicone resin having a silyl group-terminated polyether), cyanoacrylate, and acrylic resin.

  One of the first adhesive layer 4 or the second adhesive layer 5 is a layer formed from a pressure-sensitive adhesive, and the other is a layer formed from a thermosetting adhesive or an ultraviolet curable adhesive. It is preferable because the heat resistance of the polarizing plate is remarkably improved.

(Sealing agent)
Next, the sealant used in the present invention will be described. The sealing agent 6 covers the side surface of the polarizer 3, and the side surface of the polarizer 3 is brought into contact with the outside air by coating the side surface with the sealing agent and laminating the single crystal substrate and the amorphous substrate. Is prevented or suppressed. Thereby, the heat resistance and light resistance of a polarizing plate can be improved.

  The mode of covering the side surface of the polarizer 3 with the sealant 6 uses a single crystal substrate 1 and an amorphous substrate 2 having a larger area than the polarizer 3 as shown in FIG. It is not limited to what forms the sealing agent 6 only between the quality substrates 2, For example, an aspect as shown in FIGS.

  The polarizing plate of FIG. 2 is an example in which the amorphous substrate 2 has a smaller area than the polarizer 3, the first adhesive layer 4, and the second adhesive layer 5. The outer periphery of the polarizer 3, the first adhesive layer 4 and the second adhesive layer 5, and the side surface of the amorphous substrate 2, which are in a narrow portion between the single crystal substrate 1 and the amorphous substrate 2, are covered. ing. The polarizing plate of FIG. 3 is an example in which the single crystal substrate 1 and the amorphous substrate 2 have a smaller area than the polarizer 3, the first adhesive layer 4, and the second adhesive layer 5. The outer periphery of the polarizer 3, the first adhesive layer 4, and the second adhesive layer 5 protruding outward from the single crystal substrate 1 and the amorphous substrate 2 by the stopper 6 The amorphous substrate 2 is covered together with the side surfaces.

  As the sealant 6, a conventionally known one can be used, but preferably has fluidity at the time of processing and has a sealing function by being cured after processing. For example, an ultraviolet curable resin, a thermosetting resin, or a resin that can be cured by both actions can be suitably used. When a resin having fluidity at the time of processing is used, the viscosity before curing of the resin is preferably 100 Pa · s or less, more preferably in the range of 0.01 Pa · s to 50 Pa · s.

  The sealant 6 may be of the same type as the adhesive A or B, specifically, a thermosetting epoxy resin adhesive (for example, a thermosetting epoxy resin EP582 manufactured by Cemedine). Thermosetting adhesives such as urethane resin adhesives and phenol resin adhesives; UV curable epoxy resins (for example, ADEKA UV curable epoxy resin KR695A, ThreeBond UV curable epoxy resin TB3025G, Nagase Chem Examples thereof include ultraviolet curable adhesives such as UV curable resin XNR5516Z manufactured by Tex Corporation, silicone resins (for example, ultraviolet curable silicones, modified silicone resins having a silyl group-terminated polyether), cyanoacrylates, and acrylic resins.

  When a curable resin is used as the sealant 6, the volatile component before curing is preferably 2% by weight or less, more preferably 1% by weight or less. When the sealant has a volatile component of 2% by weight or less, generation of microbubbles in the sealant after processing can be suppressed, and the sealant can be applied under reduced pressure, which greatly improves processing yield. To do. Here, the volatile component is a value measured according to JIS K 6249.

  Moreover, it is preferable that the glass transition temperature after hardening of the sealing agent 6 is 80 degreeC or more, and it is preferable that a boiling absorption rate is 4 weight% or less. As a result, the heat resistance of the polarizing plate is further improved, and the penetration of moisture from the atmosphere into the polarizer can be further suppressed, so that the light resistance of the polarizing plate can be further improved. Here, the boiling water absorption rate means the percentage of the weight increased after the cured product is immersed in boiling water for 1 hour with respect to the weight of the cured product before immersion, and is obtained in accordance with JIS K 6911.

The moisture permeability of the sealant 6 is usually preferably 60 g / (m ² · 24 hr) or less, more preferably 25 g / (m ² · 24 hr) or less. When the moisture permeability of the sealant is 60 g / (m ² · 24 hr) or less, the intrusion of moisture from the atmosphere into the polarizer can be further suppressed, and the light resistance of the polarizing plate can be further improved. Here, the moisture permeability is determined according to JIS Z 0208 as the amount of moisture that permeates the cured sealant adjusted to a thickness of 100 μm in an environment of a temperature of 40 ° C. and a relative humidity of 90%.

  The width of the sealant 6 is preferably 0.1 mm or more from the end of the polarizer 3. In particular, it is preferable that the width of the sealant 6 is 0.5 mm to 3 mm because both the downsizing of the polarizing plate and the prevention of moisture intrusion into the polarizer 3 from the atmosphere can be realized.

(Retardation film)
As shown in FIGS. 4 and 5, the polarizing plate of the present invention further includes a retardation film laminated on the surface opposite to the polarizer 3 in the single crystal substrate 1 and / or the amorphous substrate 2. May be. FIG. 4 shows an example in which the retardation film 12 is laminated on the surface of the amorphous substrate 2 via the third adhesive layer 11, and FIG. 5 shows the third adhesive layer 11 via An example in which a retardation film 12 is laminated on the surface of a single crystal substrate 1 is shown.

  The retardation film 12 used in the present invention is not particularly limited, and a conventionally known film can be used. For example, a tilted or hybrid oriented discotic liquid crystal held in a matrix made of a transparent organic polymer Can be used. As a matrix material for the retardation film, an organic polymer film excellent in environmental resistance and chemical resistance such as triacetyl cellulose, polycarbonate, and polyethylene terephthalate is usually preferable.

  Examples of the adhesive forming the third adhesive layer 11 include a curable adhesive and a pressure-sensitive adhesive, but a pressure-sensitive adhesive such as an acrylic pressure-sensitive adhesive is preferably used.

  The polarizing plate of the present invention having the above-described configuration can be suitably applied to a projection type liquid crystal display device (projector), and specifically, blue channel and green channel of the projection type liquid crystal display device (projector). , And as a red channel polarizing plate. In particular, it is useful as a polarizing plate for blue channels and green channels that require higher light resistance and heat resistance.

<Production method of polarizing plate>
The manufacturing method of the polarizing plate of this invention is used suitably as a method for manufacturing the polarizing plate of the said invention, and basically includes the following processes.
(A) forming a first adhesive layer 4 on one surface of the polarizer 3 and / or one surface of the single crystal substrate 1;
(B) forming the second adhesive layer 5 on the other surface of the polarizer 3 and / or one surface of the amorphous substrate 2;
(C) obtaining a laminate in which the single crystal substrate 1, the first adhesive layer 4, the polarizer 3, the second adhesive layer 5 and the amorphous substrate 2 are laminated in this order; and
(D) The process of coat | covering the side surface of the polarizer 3 with the sealing agent 6. FIG.

  When the thermosetting or ultraviolet curable adhesive that is the adhesive B is used for one of the first adhesive layer 4 or the second adhesive layer 5, the manufacturing method of the polarizing plate of the present invention is usually A step of curing the curable or ultraviolet curable adhesive by heating or irradiation with ultraviolet rays is included. Moreover, when the sealing agent 6 consists of thermosetting or ultraviolet curable resin, the said process (D) normally includes the process of hardening the sealing agent 6 by heating or irradiation of an ultraviolet-ray. From the viewpoint of simplifying the process, curing of the adhesive when using the thermosetting or ultraviolet curable adhesive as the adhesive B may be performed simultaneously with the curing of the sealant 6 in the step (D). preferable.

  The order in particular of said process (A) and process (B) is not restrict | limited, It is also possible to carry out simultaneously.

A specific embodiment of the method for producing a polarizing plate of the present invention is an example in which the adhesive A and the adhesive B are used as adhesives for forming the first adhesive layer 4 and the second adhesive layer 5. For example, it is as follows.
(1) Adhesives A and B are respectively applied to both surfaces of the polarizer 3 to form first and second adhesive layers 4 and 5, and the first and second adhesive layers 4 and 5 are formed. The single crystal substrate 1 and the amorphous substrate 2 are bonded to each other, and then the side surfaces of the polarizer 3 are covered with a sealing agent 6 to form a sealing portion.
(2) The adhesive A is applied to one surface of the single crystal substrate 1, the polarizer 3 is bonded to the obtained first adhesive layer 4, and the adhesive B is applied to the other surface of the polarizer 3. Then, the amorphous substrate 2 is bonded to the obtained second adhesive layer 5, and then the side surface of the polarizer 3 is covered with the sealing agent 6 to form a sealing portion.
(3) The adhesive B is applied to one surface of the single crystal substrate 1, the polarizer 3 is bonded to the obtained first adhesive layer 4, and the adhesive A is applied to the other surface of the polarizer 3. Then, the amorphous substrate 2 is bonded to the obtained second adhesive layer 5, and then the side surface of the polarizer 3 is covered with the sealing agent 6 to form a sealing portion.
(4) The adhesive A is applied to one surface of the single crystal substrate 1, the polarizer 3 is bonded to the obtained first adhesive layer 4, and the adhesive B is separately applied to one surface of the amorphous substrate 2. The polarizer 3 is bonded to the obtained second adhesive layer 5 on the surface where the first adhesive layer 4 is not formed, and then the side surface of the polarizer 3 is bonded with the sealant 6. A method of forming a sealing portion by coating.
(5) The adhesive B is applied to one surface of the single crystal substrate 1, the polarizer 3 is bonded to the obtained first adhesive layer 4, and the adhesive A is separately applied to one surface of the amorphous substrate 2. The polarizer 3 is bonded to the obtained second adhesive layer 5 on the surface where the first adhesive layer 4 is not formed, and then the side surface of the polarizer 3 is bonded with the sealant 6. A method of forming a sealing portion by coating.
(6) The adhesive A is applied to one surface of the polarizer 3, the single crystal substrate 1 is bonded to the obtained first adhesive layer 4, and the adhesive B is applied to the other surface of the polarizer 3. Then, the amorphous substrate 2 is bonded to the obtained second adhesive layer 5, and then the side surface of the polarizer 3 is covered with the sealing agent 6 to form a sealing portion.
(7) The adhesive B is applied to one side of the polarizer 3, the single crystal substrate 1 is bonded to the obtained first adhesive layer 4, and the adhesive A is applied to the other side of the polarizer 3. Then, the amorphous substrate 2 is bonded to the obtained second adhesive layer 5, and then the side surface of the polarizer 3 is covered with the sealing agent 6 to form a sealing portion.
(8) The adhesive A is applied to one side of the polarizer 3 to form the second adhesive layer 5, while the adhesive B is applied to one side of the single crystal substrate 1 to obtain the first obtained The surface of the polarizer 3 where the adhesive A is not applied is bonded to the adhesive layer 4, the amorphous substrate 2 is bonded to the second adhesive layer 5, and then the polarizer 3 is bonded with the sealant 6. A method of forming a sealing portion by covering the side surface of the substrate.
(9) The adhesive B is applied to one surface of the polarizer 3 to form the second adhesive layer 5, while the adhesive A is applied to one surface of the single crystal substrate 1 to obtain the first obtained The surface of the polarizer 3 on which the adhesive B is not applied is bonded to the adhesive layer 4, the amorphous substrate 2 is bonded to the second adhesive layer 5, and then the polarizer 3 is bonded with the sealant 6. A method of forming a sealing portion by covering the side surface of the substrate.

  In the method for producing a polarizing plate of the present invention, the formation of the first adhesive layer 4 in the step (A) and the formation of the second adhesive layer 5 in the step (B) may be performed under reduced pressure. preferable. Thereby, mixing of air bubbles into the first adhesive layer 4 and the second adhesive layer 5 is prevented, and the yield of the polarizing plate can be improved. Further, since bubbles can be prevented from being mixed between the single crystal substrate 1 and the amorphous substrate 2 and the polarizer 3, the polarizer 3, the single crystal substrate 1 and the amorphous substrate 2 in the above step (C). It is also preferable that the bonding with is also performed under reduced pressure. Furthermore, for the same reason, the coating with the sealant 6 in the step (D) is also preferably performed under reduced pressure. The degree of reduced pressure is not particularly limited, but is usually about 500 Pa or less.

  Moreover, it is preferable that the manufacturing method of the polarizing plate of this invention includes the process of drying the polarizer 3. FIG. As described above, a conventionally known method can be used as the drying method, and examples thereof include a heat drying method and a vacuum drying method. The heat drying method is preferable from the viewpoint of simplicity of production equipment for the polarizing plate. Examples of the heat drying method include a method of putting in a heating oven, a method of irradiating light to the polarizer, and utilizing the heat generated by the polarizer itself by absorption of the light of the polarizer. The heating temperature in the heat drying method is preferably 130 ° C. or less, more preferably 40 ° C. to 130 ° C., regardless of the heating method. By setting the temperature to 40 ° C. or higher, drying can be completed in a relatively short time. By setting the temperature to 130 ° C. or lower, the adhesive is deteriorated or the adhesive is dried after the adhesive layer is formed. Deterioration of the layer can be suppressed.

  The drying process can be performed at any stage. For example, the drying process can be performed in a state where the adhesive layer and the substrate are not joined, or the first adhesive layer 4 and / or the second adhesion. It can be performed at the stage where the agent layer 5 is laminated, or can be performed at the stage where the single crystal substrate 1 and / or the amorphous substrate 2 are joined. If one of the crystalline substrates 2 is bonded to one side (that is, after the step (A) or after the step (B)), the flatness of the polarizer can be maintained. It is preferable because moisture removal from the surface where the substrate of the polarizer 3 is not bonded is performed quickly. Further, in this case, there is an advantage that moisture does not enter from the substrate side after drying, and it is easy to maintain the dried state of the polarizer. In addition, when the substrate is bonded to one surface of the polarizer 3 and dried, and the substrate is bonded to the other surface of the polarizer and then dried again, the polarizer can be further dried. preferable.

  As described above, the polarizer 3 is preferably dried at any one or more of the above stages, but the moisture content of the polarizer 3 is adjusted to 5 wt% or less by the drying step. Is preferable, and it is more preferable to adjust to 1 weight% or less. In the polarizer formed by adsorbing and orienting the dichroic dye on the polyvinyl alcohol-based resin film, the decomposition of the dichroic dye can be more effectively suppressed by setting the water content to 5% by weight or less. The light resistance of the obtained polarizing plate can be greatly improved.

<Projection type liquid crystal display device>
Next, the projection type liquid crystal display device of the present invention will be described. A projection-type liquid crystal display device of the present invention includes a liquid crystal display panel (hereinafter sometimes referred to as “LCD panel”) including a liquid crystal cell and the polarizing plate of the present invention disposed on one or both surfaces of the liquid crystal cell. Including. That is, the LCD panel constituting the projection type liquid crystal display device of the present invention includes a liquid crystal cell, an incident side polarizing plate laminated on one surface of the liquid crystal cell, and an output laminated on the other surface of the liquid crystal cell. A side polarizing plate is provided, and at least one of the polarizing plates, preferably both polarizing plates, are constituted by the polarizing plate of the present invention.

  In the LCD panel, the polarizing plate of the present invention is preferably disposed so that the amorphous substrate side faces the liquid crystal cell. When a single crystal substrate is disposed between the liquid crystal cell and the polarizer and a deviation occurs between the optical axis of the single crystal substrate and the polarization axis of the polarizer, the contrast of the projected image tends to decrease. By disposing an amorphous substrate between the liquid crystal cell and the polarizer, such a problem can be solved and a liquid crystal display device in which a decrease in contrast is suppressed can be obtained.

  FIG. 6 is a diagram schematically showing an example of a projection type liquid crystal display device (projector) of the present invention. Hereinafter, the configuration and optical system of the projection type liquid crystal display device shown in FIG. 6 will be described.

  A light bundle using a high-pressure mercury lamp 111 as a light source (in FIG. 6, light rays having different wavelengths are represented by different types of lines) are firstly converted into a first lens array 112, a second lens array 113, and a polarization conversion. The light passes through the element 114 and the superimposing lens 115 in order, whereby the luminance is uniformized and polarized in the cross section of the anti-beam bundle. Specifically, the light bundle emitted from the high-pressure mercury lamp 111 as a light source is divided into a large number of minute light bundles by the first lens array 112 in which minute lenses 112a are arranged in a matrix. In the second lens array 113 and the superimposing lens 115, each of the divided light bundles irradiates the entire incident-side surface of the red liquid crystal cell 140R, the green liquid crystal cell 140G, and the blue liquid crystal cell 140B that are illumination targets. Provided for. Thereby, the entire incident side surface of each liquid crystal cell has a substantially uniform illuminance.

  The polarization conversion element 114 is usually configured by a polarization beam splitter array, and is disposed between the second lens array 113 and the superimposing lens 115. As a result, random polarized light from the light source is converted into polarized light having a specific polarization direction in advance, thereby reducing the light loss at the incident-side polarizing plate described later, thereby improving the screen brightness.

  The light with uniform brightness and polarization is separated into the red channel, the green channel, and the blue channel sequentially through the reflection mirror 122 by the dichroic mirrors 121, 123, and 132 for separating the three primary colors of RGB. The red channel and the blue channel are further passed through the reflecting mirror 134 and further passed through a lens 135 for condensing on the respective channels, and the red liquid crystal cell 140R, the green liquid crystal cell 140G, and the blue liquid crystal, respectively. The light enters the cell 140B.

  On the incident side and the exit side of the red liquid crystal cell 140R, the green liquid crystal cell 140G, and the blue liquid crystal cell 140B, an incident side polarizing plate 142 and an output side polarizing plate 143 are disposed, respectively. The liquid crystal cell and the emission side polarizing plate 143 constitute an LCD panel. In the projection type liquid crystal display device of the present invention, at least one of the incident-side polarizing plate 142 and the outgoing-side polarizing plate 143, preferably both polarizing plates, is the polarizing plate of the present invention. The incident-side polarizing plate 142 and the outgoing-side polarizing plate 143 disposed in the RGB optical paths are disposed so that the absorption axes thereof are orthogonal to each other, and the red liquid crystal cell 140R, the green liquid crystal cell 140G, and the blue liquid crystal cell 140B. In each of these, the function of converting the polarization state controlled for each pixel by the image signal into the light amount is achieved.

  The polarizing plate of the present invention can be used as any polarizing plate of blue channel, green channel, and red channel as a polarizing plate having excellent durability, and among them, blue that requires higher light resistance and heat resistance. It is useful as a polarizing plate for channels and green channels. Regardless of the type of dichroic dye used in the polarizer, the configuration can be the same for any channel. Also in each LCD panel, the polarizing plate of the present invention is preferably disposed so that the amorphous substrate side faces the liquid crystal cell.

  An optical image created by transmitting incident light with different transmittance for each pixel according to the image data of the red liquid crystal cell 140R, the green liquid crystal cell 140G, and the blue liquid crystal cell 140B is generated by the cross dichroic prism 150. The combined image is enlarged and projected onto the screen 180 by the projection lens 170.

  The present invention will be described in more detail with reference to examples below, but the present invention is not limited to these examples. Evaluation test methods for light resistance and heat resistance of polarizing plates prepared in Examples and Comparative Examples are as follows. Moreover, the following method evaluated the grade of the black nonuniformity of the screen at the time of applying a polarizing plate to a projection type liquid crystal display device.

(1) Light Resistance Test of Polarizing Plate Using the light resistance evaluation apparatus shown in FIG. 7, the light resistance of the polarizing plate after being left for 72 hours immediately after manufacturing and in an environment of 60 ° C. and 90% relative humidity immediately after manufacturing. (Hereinafter also referred to as initial evaluation and long-term evaluation, respectively).

  7 uses a 130 W high-pressure mercury lamp 20 manufactured by Philips as a light source, and includes a UV / IR cut filter 21, a fly-eye lens 22, a polarization beam splitter array 23, a dichroic mirror 24, and a lens 25. And an optical system similar to the optical system of the projector. The white light 27 irradiated from the high-pressure mercury lamp 20 is separated into red / green light 28 and blue light 29 by the dichroic mirror 24, and the blue light 29 is irradiated onto the polarizing plate installed in the sample holder 26. It is configured to be able to.

A polarizing plate was placed in the sample holder 26 of the light resistance evaluation apparatus, and light resistance was evaluated based on whether or not light leakage occurred due to deterioration of the polarizer. The amount of light applied to the polarizing plate was 3.0 W per cm ² . In this test, the light resistance as a blue channel polarizing plate was evaluated. When the transmittance in the absorption axis direction at 440 nm was 0.3% or less, it was evaluated as “no light leakage”. In the light resistance column, “◯” was written, and when the transmittance was 0.3% or more, “light leakage” was evaluated, and “×” was written in the light resistance column of Table 1.

  Light leakage is a phenomenon of polarizer deterioration that occurs after being introduced into a light resistance evaluation apparatus, and is a phenomenon in which the transmittance in the absorption axis direction increases. When the polarizing plate to be evaluated and a normal polarizing plate are arranged in crossed Nicols, if the light resistance is good, the transmittance is sufficiently low and no light leakage occurs, but the light resistance is low and the light resistance evaluation device If deterioration of the polarizer such as decomposition of the dichroic dye occurs after being introduced into the light, the transmittance in the absorption axis direction of the polarizer increases and light leakage occurs.

(2) Heat resistance test of polarizing plate The obtained polarizing plate was allowed to stand for 72 hours in an environment of 110 ° C., and then the presence or absence of peeling of the polarizer was visually observed. When peeling did not occur, it was evaluated as having sufficient heat resistance, and “◯” was described in the heat resistance test column of Table 1. Moreover, when peeling generate | occur | produced, it was set as heat resistance inadequate and x was described in the column of the heat resistance test of Table 1.

(3) Evaluation of black unevenness The polarizing plate produced in each Example was attached as the blue channel exit side polarizing plate 143 of the rear projector shown in FIG. At this time, the polarizing plate was placed so that the amorphous substrate was on the liquid crystal cell side. Then, the black screen is displayed, the luminance distribution on the screen is measured, the difference between the maximum value and the minimum value x (pp) and the maximum value of the y value represented by the black screen xy display system, The difference y (pp) from the minimum value was calculated. These differences mean that the smaller the value, the less black unevenness on the black screen. The results for the polarizing plates of Examples 1 to 5 are shown in Table 1.

<Example 1>
A polarizing plate having the structure shown in FIG. 1 was produced as follows. First, a polyvinyl alcohol film (“VF-PX” manufactured by Kuraray Co., Ltd.) was uniaxially stretched, dyed with a dye that absorbs blue color, and dried to obtain a polarizer 3 for a projector blue channel. The polarizer 3 had a thickness of 28 μm, a degree of polarization at 440 nm of 99.9%, and a transmittance of 44.0%.

A first adhesive layer made of “KR695A” (epoxy ultraviolet curable resin, ADEKA Corporation KR695A: glass transition temperature 90 ° C.) as the adhesive B is formed on one surface of the polarizer 3 thus obtained. 4 is formed under reduced pressure (500 Pa or less), and through this, a single crystal substrate 1 which is a quartz substrate having a thickness of 0.5 mm (linear thermal expansion coefficient in the direction parallel to the C axis 71 × 10 ⁻⁷ / ° C) was joined under reduced pressure (500 Pa or less). And it dried in the oven adjusted to 80 degreeC for 24 hours, and adjusted the moisture content of the polarizer 3 to 5 weight% or less. Thereafter, the second adhesive layer 5 made of “adhesive 1” as an adhesive A (acrylic adhesive: glass transition temperature: −50 ° C., manufactured by Lintec) is reduced in pressure on the other surface of the polarizer 3. The amorphous substrate 2 (coefficient of linear thermal expansion 74 × 10 ⁻⁷⁾ made of zinc borosilicate glass having a thickness of 0.1 mm, formed by the downdraw method, is formed thereunder. / ° C.) was joined under reduced pressure (500 Pa or less). Then, the sealing agent 6 which consists of ultraviolet curable epoxy resin (Threebond Co., Ltd. TB3025G: moisture permeability 10g / m < ² > * 24hr) under pressure reduction (500 Pa or less) so that the exposed part (side surface) of the polarizer 3 may be covered. Then, the sealing agent 6 and the first adhesive layer 4 were cured by ultraviolet irradiation to obtain a polarizing plate having the configuration shown in FIG. In addition, the antireflection film which consists of a dielectric material layer by vacuum evaporation was formed in the surface in the side which contact | connects the air in the used quartz substrate and zinc borosilicate glass substrate.

  The obtained polarizing plate showed no light leakage in the initial evaluation and the long-term evaluation, and showed good light resistance. Moreover, peeling of the polarizer was not recognized in the heat resistance test, and sufficient heat resistance was shown.

<Example 2>
A polarizing plate was produced in the same manner as in Example 1 except that the thickness of the amorphous substrate 2 made of zinc borosilicate glass was 0.21 mm. The produced polarizing plate was subjected to initial evaluation and long-term evaluation in the same manner as in Example 1. As a result, no light leakage was observed. Similarly, when a heat resistance test was performed, no peeling of the polarizer was observed.

<Example 3>
A polarizing plate was produced in the same manner as in Example 1 except that the thickness of the amorphous substrate 2 made of zinc borosilicate glass was 0.3 mm. The produced polarizing plate was subjected to initial evaluation and long-term evaluation in the same manner as in Example 1. As a result, no light leakage was observed. Similarly, when a heat resistance test was performed, no peeling of the polarizer was observed.

<Example 4>
A polarizing plate was produced in the same manner as in Example 1 except that 0.1 mm thick blue plate glass (linear thermal expansion coefficient 83 × 10 ⁻⁷ / ° C.) was used as the amorphous substrate 2. The produced polarizing plate was subjected to initial evaluation and long-term evaluation in the same manner as in Example 1. As a result, no light leakage was observed. Similarly, when a heat resistance test was performed, no peeling of the polarizer was observed.

<Example 5>
A polarizing plate was produced in the same manner as in Example 1 except that 0.3 mm-thick blue plate glass was used as the amorphous substrate 2. The produced polarizing plate was subjected to initial evaluation and long-term evaluation in the same manner as in Example 1. As a result, no light leakage was observed. Similarly, when a heat resistance test was performed, no peeling of the polarizer was observed.

<Comparative Example 1>
A polarizing plate was produced in the same manner as in Example 1, except that 0.3 mm quartz glass (linear thermal expansion coefficient 5.5 × 10 ⁻⁷ / ° C.) was used as the amorphous substrate 2. About the produced polarizing plate, when the heat resistance test was done like Example 1, peeling of the polarizer generate | occur | produced.

<Comparative Example 2>
A polarizing plate was produced in the same manner as in Example 1 except that the side surface of the polarizer 3 was not sealed with the sealant 6. About the produced polarizing plate, when the light resistance test was implemented similarly to Example 1, light leakage generate | occur | produced in long-term evaluation.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The polarizing plate of the present invention is excellent in light resistance and heat resistance. Thereby, when it uses for a projection-type liquid crystal display device, the lifetime improvement of a projection-type liquid crystal display device is realizable. Moreover, when the polarizing plate of this invention is used for a projection-type liquid crystal display device, the deterioration of the image quality of a projection screen can be suppressed.

  DESCRIPTION OF SYMBOLS 1 Single crystal substrate, 2 Amorphous substrate, 3,803 Polarizer, 4 1st adhesive bond layer, 5 2nd adhesive bond layer, 6 Sealant, 11 3rd adhesive bond layer, 12 Retardation film , 20, 111 High pressure mercury lamp, 21 UV / IR cut filter, 22 Fly eye lens, 23 Polarizing beam splitter array, 24, 121, 123, 132 Dichroic mirror, 25, 135 Lens, 26 Sample holder, 27 White light, 28 Red / green light, 29 blue light, 112 first lens array, 112a minute lens, 113 second lens array, 114 polarization conversion element, 115 superimposing lens, 122,134 reflection mirror, 140R red liquid crystal cell, 140G Green liquid crystal cell, 140B Blue liquid crystal cell, 142 Incident side polarizing plate, 143 Outgoing side polarizing plate 150 Cross dichroic prism, 170 projection lens, 180 screen, 801, 802 glass plate, 804 adhesive layer.

Claims (14)

A polarizer, a single crystal substrate laminated on one surface of the polarizer via a first adhesive layer, and a non-crystal laminated on the other surface of the polarizer via a second adhesive layer A polarizing plate comprising a crystalline substrate,
The side surface of the polarizer is coated with a sealant,
The absolute value of the difference between the linear thermal expansion coefficient in the direction parallel to the C axis of the single crystal substrate and the linear thermal expansion coefficient of the amorphous substrate is 30 × 10 ⁻⁷ / ° C. or less.
The polarizing plate which has a glass transition temperature different from a said 1st adhesive bond layer and a said 2nd adhesive bond layer.   The polarizing plate according to claim 1, wherein the difference between the glass transition temperature of the first adhesive layer and the glass transition temperature of the second adhesive layer is 60 ° C. or more.   One of the first adhesive layer or the second adhesive layer is a layer formed from a pressure-sensitive adhesive, and the other is a layer formed from a thermosetting adhesive or an ultraviolet curable adhesive. The polarizing plate according to claim 1 or 2.   The polarizing plate according to claim 1, wherein the single crystal substrate is made of quartz or sapphire.   The polarizing plate according to claim 1, wherein the single crystal substrate has a thermal conductivity of 5 W / mK or more.   The polarizing plate according to claim 1, wherein the polarizer has a water content of 5% by weight or less.   The polarizing plate according to claim 1, wherein the polarizer is obtained by adsorbing and orienting a dichroic dye or iodine on a film made of a polyvinyl alcohol-based resin.   The polarizing plate according to claim 7, wherein the polarizer is made of a polyvinyl alcohol / polyvinylene block copolymer.   The polarizing plate according to claim 1, further comprising a retardation film laminated on a surface opposite to the polarizer in the single crystal substrate and / or the amorphous substrate. A method for producing a polarizing plate according to claim 1,
Forming a first adhesive layer on one side of the polarizer and / or one side of the single crystal substrate;
Forming a second adhesive layer on the other surface of the polarizer and / or one surface of the amorphous substrate;
Obtaining a laminate in which a single crystal substrate, a first adhesive layer, a polarizer, a second adhesive layer, and an amorphous substrate are laminated in this order;
Coating the side surface of the polarizer with a sealant;
The manufacturing method of a polarizing plate provided with.   The method for producing a polarizing plate according to claim 10, wherein the formation of the first adhesive layer and the second adhesive layer is performed under reduced pressure.   The manufacturing method of the polarizing plate of Claim 10 or 11 further equipped with the process of drying the said polarizer at the temperature of 130 degrees C or less.   A projection type liquid crystal display device comprising: a liquid crystal cell; and the polarizing plate according to claim 1 disposed on at least one side of the liquid crystal cell.   The projection-type liquid crystal display device according to claim 13, wherein the polarizing plate is disposed so that the amorphous substrate side faces the liquid crystal cell.

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