CN101122647A - Polarizing plate and method for producing same - Google Patents

Abstract

A polarizing plate having transparent substrates on both surfaces of a polarizing film including a polarizer, wherein an exposed portion of the polarizing film not covered with the transparent substrates is covered with a sealing material.

Description

Polarizing plate and its manufacturing method

Background of the invention

technical field

The invention relates to a polarizer and a manufacturing method thereof.

Description of prior art

In order to meet the needs of increasing screen size, projection-type liquid crystal displays are rapidly popularized in public and home use instead of conventional cathode-ray tube-type displays.

Projection-type liquid crystal display is such a system, in which the light emitted by the light source is separated into three primary colors of RGB, and then each light passes through a liquid crystal panel, a polarizer, etc. along its own optical path, and is finally enlarged by a projection lens to form the desired displayed image. As projection-type liquid crystal displays, front projectors that project images from the viewer's side onto the screen are mainly used for public use, and rear projectors that project images from the rear side of the screen to the viewer are mainly used for home use.

Recently, in projection-type liquid crystal displays, the brightness of the screen has gradually increased, so high-pressure mercury lamps that emit strong light have been used. Therefore, it is necessary to make the polarizer placed in the optical path have the characteristics of being able to resist strong light and heat for a long time, that is, light resistance, so the light resistance of the polarizer becomes an important factor in determining the service life of a projection-type liquid crystal display.

Recently, it has been reported that by combining a polarizing film comprising a polarizer and a protective film to a transparent substrate made of a material with high thermal conductivity, the heat generated by the polarizing film is released from the transparent substrate to reduce the temperature of the polarizing film, thereby improving the polarizing film. For example, it is suggested to adopt a polarizer made of a transparent substrate made of high thermal conductivity sapphire glass (Patent Document 1: JP-A No.2000-206507, [Claim 1], [0029] ) and a polarizer using a YAG substrate with high thermal conductivity as a transparent substrate (patent document 2: JP-A No. 2002-55231, [claim 1], [0005]).

Patent Document 3 (JP-A No. 10-39138, [Claim 1], [0004]) provides a structure in which a transparent substrate directly sandwiches a polarizer without using a protective film, so that the Heat is conducted directly to the transparent substrate.

There is a continuing trend to increase the amount of light in projectors to meet the need to increase screen brightness. It is apparent that the substrate improvements disclosed in Patent Documents 1 and 2 cannot ensure sufficient light resistance.

Even by the method of Patent Document 3, there is a problem that sufficient light resistance cannot be ensured.

Summary of the invention

The invention provides a polarizer and a manufacturing method thereof, which has excellent light resistance compared with traditional polarizers and solves the above technical problems.

In order to obtain further improvement in light resistance, the inventors of the present invention have investigated and found that in a polarizer having a transparent substrate on both surfaces of the polarizing film, it can be improved by sealing the exposed portion of the polarizing film not covered by the transparent substrate. Light fastness.

That is, the present invention provides the following [1] to [30]:

[1] A polarizing plate having a transparent substrate on both surfaces of a polarizing film including a polarizer, wherein an exposed portion of the polarizing film not covered by the transparent substrate is covered with a sealing material.

[2] The polarizing plate according to [1], wherein the water content of the polarizer is 5 wt% or less.

[3] The polarizing plate according to [1], wherein the sealing material is an ultraviolet curable adhesive or a heat curable adhesive.

[4] The polarizing plate according to [3], wherein the sealing material has a glass transition temperature after curing of 80° C. or more.

[5] The polarizing plate according to [3], wherein the sealing material has a viscosity before curing of 10 Pa·s or less at 25°C.

[6] The polarizing plate according to [1], wherein the sealing material has a boiling water absorption coefficient after curing of 4% by weight or less.

[7] The polarizing plate according to [1], wherein the sealing material has a boiling water absorption coefficient after curing of 2% by weight or less.

[8] The polarizing plate according to [1], wherein at least one of the transparent substrates is made of a material having a thermal conductivity of 5 W/mK or more.

[9] The polarizing plate according to [1], wherein a resin layer is formed between the transparent substrate made of a material having a thermal conductivity greater than or equal to 5 W/mK and the polarizer, and the total thickness of the resin layer is greater than or equal to 0.1 μm and less than 10 μm.

[10] The polarizing plate according to [9], wherein the material of one transparent substrate is quartz crystal or sapphire, and the material of the other substrate is quartz crystal, quartz glass, silicate glass or borosilicate glass.

[11] The polarizing plate according to [1], wherein the polarizing film is a polarizing film comprising a polarizer and a protective film.

[12] The polarizing plate according to [11], wherein the polarizing film has a water content of 1.6 wt% or more.

[13] The polarizing plate according to [11], wherein the protective film has a thickness of 10 to 45 μm.

[14] The polarizing plate according to [11], wherein the protective film is a film containing triacetyl cellulose or an olefin resin film.

[15] The polarizing plate according to [11], wherein at least one of the transparent substrates is made of a material having a thermal conductivity greater than or equal to 5 W/mK.

[16] The polarizing plate according to [11], wherein a resin layer having a total thickness of more than Or equal to 0.1 μm and less than 10 μm.

[17] The polarizing plate according to [16], wherein the material of one transparent substrate is quartz crystal or sapphire, and the material of the other substrate is quartz crystal, quartz glass, silicate glass or borosilicate glass.

[18], the polarizing plate according to [11], wherein the polarizing film is composed of a polarizer and a protective film, transparent substrates are pasted on both surfaces of the polarizing film, and the transparent substrate pasted on the polarizer is made of a Transparent substrates made of optically anisotropic materials.

[19] The polarizing plate according to [18], wherein the transparent substrate having non-optical anisotropy is made of silicate glass or borosilicate glass.

[20] The polarizing plate according to [1], wherein the plate has a laminated portion having a thickness of 1 μm or more and 30 μm or less between the polarizer and at least one transparent substrate, the laminated portion being cured by heat Composed of two or more resin layers formed of resin or ultraviolet curable resin, the laminated part includes an adhesive layer.

[21] The polarizing plate according to [20], wherein the content of volatile components of the resin layer formed in the polarizing plate before curing is 2% by weight or less.

[22] The polarizing plate according to [20], wherein the resin layer formed in the polarizing plate has a viscosity at 25° C. before curing of 0.01 Pa·s or more and 20 Pa·s or less.

[23] The polarizing plate according to [20], wherein when the resin layer formed in the polarizing plate has a thickness of 25 μm after being cured, the light transmittance in the wavelength range of 400 nm to 700 nm is greater than or equal to 90%.

[24] A method of manufacturing a polarizing plate having a transparent substrate on both surfaces of a polarizing film including a polarizer, and wherein an exposed portion of the polarizing film not covered with the transparent substrate is covered with a sealing material , wherein the transparent substrate is bonded to both surfaces of the polarizing film with resin, the polarizing film is dried, and then the exposed portion of the polarizing film not covered by the transparent substrate is covered with a sealing material.

[25] The method for producing a polarizing plate according to [24], wherein in the process of bonding the transparent substrate to the polarizing film with a resin, at least one of the following steps is performed under reduced pressure: A process of forming a resin layer before curing the resin used as an adhesive layer, and a process of setting an object to be bonded.

[26] The method of manufacturing a polarizing plate according to [24], wherein the method includes a step of drying the polarizing film at a temperature of 110° C. or less before bonding the second transparent substrate to the polarizing film.

[27] The method of manufacturing a polarizing plate according to [24], wherein at least one of the transparent substrates has a recessed portion and/or a hole portion for injecting a sealant, and the method includes injecting through the recessed portion and/or hole portion Sealant process.

[28] A projection type liquid crystal display having the polarizing plate according to [1].

[29] The polarizing plate according to [1], wherein when the resin covering the exposed portion of the polarizer has a thickness after curing of 100 μm, water vapor permeates under the conditions of an ambient temperature of 40° C. and a relative humidity of 90%. The rate is less than or equal to 60g/m ² ·24hr.

[30] The polarizing plate according to [1], wherein when the resin covering the exposed portion of the polarizer has a thickness after curing of 100 μm, water vapor permeates under conditions of an ambient temperature of 40° C. and a relative humidity of 90%. The rate is less than or equal to 25g/m ² ·24hr.

Description of drawings

Fig. 1 is a schematic diagram illustrating the structure of a polarizing plate of the present invention (structural diagram of Embodiment 1).

Fig. 2 is a schematic diagram illustrating the structure of a polarizing plate of the present invention (structural diagram of Embodiment 3).

Fig. 3 is a schematic diagram illustrating the structure of the polarizing plate of the present invention.

Fig. 4 is a schematic diagram illustrating the structure of a polarizing plate of the present invention.

Fig. 5 is a schematic diagram illustrating the structure of a polarizing plate of the present invention (structural diagrams of Examples 2 and 4).

Fig. 6 is a schematic diagram illustrating the structure of a polarizing plate of the present invention.

7 is a schematic diagram illustrating the structure of a polarizing plate used in Comparative Example 1 (structural diagram of Comparative Example 1).

8 is a schematic view illustrating the structure of a polarizing plate used in Comparative Example 2 (structural diagram of Comparative Example 2).

Fig. 9 is a schematic diagram illustrating the structure of a polarizing plate of the present invention (structural diagram of Embodiment 5).

Fig. 10 is a schematic diagram illustrating the structure of a polarizing plate of the present invention.

Fig. 11 is a schematic diagram illustrating the structure of a polarizing plate of the present invention (structural diagram of Embodiment 6).

Fig. 12 is a schematic diagram illustrating the structure of a polarizing plate of the present invention.

Fig. 13 is a schematic diagram illustrating the structure of a polarizing plate of the present invention (structural diagram of Embodiment 7).

FIG. 14 illustrates a schematic diagram of the structure of a polarizing plate of a comparative example.

Fig. 15 is a schematic diagram illustrating the structure of a polarizing plate of the present invention (structural diagram of Embodiment 12).

Fig. 16 is a schematic diagram illustrating the structure of a polarizing plate of the present invention.

Fig. 17 is a schematic diagram illustrating the structure of a polarizing plate of the present invention (structural diagrams of Examples 13 and 14).

Fig. 18 is a schematic diagram illustrating the structure of a polarizing plate of the present invention.

Fig. 19 illustrates a schematic diagram of the structure of a polarizing plate of a comparative example (structural diagram of comparative example 5).

FIG. 20 illustrates a schematic diagram of the structure of a polarizing plate of a comparative example (structural diagram of Comparative Example 6).

FIG. 21 shows a transparent substrate used in Example 9.

FIG. 22 is an assembly view of a polarizing plate of Example 9. FIG.

FIG. 23 shows a transparent substrate used in Example 10.

FIG. 24 is an assembly view of a polarizing plate of Example 8. FIG.

Fig. 25 is an explanatory diagram of the optical path of the projector.

Fig. 26 shows the light resistance evaluation device.

Fig. 27 is a schematic diagram illustrating the structure of a polarizing plate of the present invention (structural diagram of Embodiment 15).

[Description of Reference Signs]

(1) Transparent substrate (transparent substrate (A), Fig. 1 to Fig. 6)

(2) Transparent substrate (transparent substrate (B), Figure 1 to Figure 6)

(3) Protective film

(4) Polarizer

(5) Sealing material

(6) Exposed portion of polarizing film without sealing material

(7) Spacer

(8) Recessed part

(9) hole part

(10) Syringes

(11) Sealing material (uncured)

(12) Sealing material flow (uncured)

(14) Resin layer (a)

(15) Resin layer (b)

(16) Resin layer (c)

(20) High pressure mercury lamp

(21) UV/IR cut filter (cut filter)

(22) flyeye lens

(23) Polarizing Beam Splitter Array

(24) dichroic mirror

(25)Lens

(26) Sample holder

(27) white light

(28) red, green light

(29) Blu-ray

(111)High pressure mercury lamp

(112) lens array

(112a) microlens

(113) lens array

(114) Polarization conversion device

(115) Overlay lens

(122) Mirror

(121) dichroic mirror

(123) dichroic mirror

(132) dichroic mirror

(134) Mirror

(135)Lens

(140R) red light LCD panel

(140G) Green LCD panel

(140B) Blu-ray LCD panel

(142) Polarizer (incident side)

(143) Polarizer (exit side)

(150)Cross dichroic prism

(170)Projection lens

(180)Screen

Detailed description of the preferred embodiment

Regarding methods of improving the light resistance of polarizers for projectors, conventionally, attempts have been made to apply a sapphire substrate having excellent thermal conductivity and to apply glass to both surfaces. However, the polarizing plate obtained by combining the above techniques, in which the sapphire substrate is used as one transparent substrate and the polarizing film is sandwiched by the transparent substrates on both surfaces thereof, cannot lead to a significant improvement in light resistance. That is, the present inventors have found that the weakness in the light fastness of polarizers is due to the traces of water remaining in the polarizer (typically, using PVA). In an embodiment in which a polarizing film is sandwiched by transparent substrates on both surfaces thereof, in order to suppress deterioration of the polarizer, the end face of the polarizing film containing the polarizer not covered by the transparent substrate is covered with a sealing material to prevent moisture in the air penetration, resulting in a significant improvement in light resistance.

That is, a preferred polarizing plate is one having a transparent substrate on both surfaces of a polarizing film including a polarizer, wherein an exposed portion of the polarizing film not covered by the transparent substrate is covered with a sealing material.

The structure of the polarizer of the present invention will be described in detail below with reference to the accompanying drawings.

1 to 6, FIGS. 9 to 13, and FIGS. 15 to 18 show the structures of the polarizing plate of the present invention, but the present invention is not limited to polarizing plates having these structures.

First, a polarizing plate without a protective film will be described.

Fig. 1 illustrates the structure of a polarizing plate of the present invention. The polarizer is connected to a transparent substrate (A) having a thermal conductivity greater than or equal to 5 W/mK via a resin layer (a), and two resin layers (b) and (c) are formed between another transparent substrate (B) and the polarizer between. The end faces (side faces) of the polarizer and the end faces of the resin layers (a), (b) and (c) were covered with a sealing material.

As shown in FIG. 2, it is also possible that the polarizer is connected to a transparent substrate (A) having a thermal conductivity greater than or equal to 5 W/mK via a resin layer (a), and two resin layers (b) and (c) are formed on another Between a transparent substrate (B) and the polarizer, and the end face of the polarizer is covered with a resin layer (b), and the end faces of the resin layers (b) and (c) are covered with a sealing material.

As shown in FIG. 3, it is also possible that the two resin layers (a) and (b) are formed between the polarizer and the transparent substrate (A) having a thermal conductivity greater than or equal to 5 W/mK, and the two resin layers (b ) and (c) are formed between the polarizer and another transparent substrate (B), and the end face of the polarizer is covered with the resin layer (b), and the end faces of the resin layers (a), (b) and (c) are covered with Covered with sealing material.

As shown in FIG. 4, it is also possible that the polarizer is connected to a transparent substrate (A) having a thermal conductivity greater than or equal to 5 W/mK via a resin layer (a), and the two layers of the resin layer (b) and the sealing material layer are formed on Between the other transparent substrate (B) and the polarizer, the end faces of the polarizer and the resin layers (a), and (b) were covered with a sealing material.

As shown in FIG. 5, it is also possible that the polarizer is connected to a transparent substrate (A) having a thermal conductivity greater than or equal to 5 W/mK via a resin layer (a), and the two layers of the resin layer (b) and the sealing material layer are formed on Between the other transparent substrate (B) and the polarizer, the end faces of the polarizer and the resin layer (a) are covered with a resin layer (b), and the end faces of the resin layer (b) are covered with a sealing material.

As shown in FIG. 6, it is also possible that two resin layers (a) and (b) are formed between the polarizer and a transparent substrate (A) having a thermal conductivity greater than or equal to 5 W/mK, and the resin layers (b) and Sealing Material Layer These two layers are formed between the polarizer and another transparent substrate (B), the end face of the polarizer is covered with a resin layer (b), and the end faces of the resin layers (a) and (b) are covered with a sealing material.

As shown in FIG. 27, it is also possible that the resin layer (a) is formed between the polarizer and the transparent substrate (A) having a thermal conductivity greater than or equal to 5 W/mK, and the resin layer (c) is formed between the polarizer and another transparent substrate (A). Between the transparent substrates (B), the end face of the polarizer is covered with a sealing material.

More preferable is a polarizing plate in which a resin layer is formed between a transparent substrate formed of a material having a thermal conductivity of 5 W/mK or more and the polarizer, and the total thickness of the resin layer is 0.1 μm or more and less than 10 μm .

A polarizing plate with a protective film will be described below.

In Fig. 9 to Fig. 13 and Fig. 15 to Fig. 18, although not shown for between the transparent substrate and the polarizer, between the transparent substrate and the protective film, between the polarizer and the protective film, between the spacer and Resin layers that are bonded between transparent substrates, etc., but these resin layers exist between each structural element.

In the case of the structure shown in Figure 9, that is, if the polarizing film is smaller than the transparent substrate (2), and the transparent substrate (1) is smaller than the polarizing film, then the part of the polarizer contacting the air, specifically the cross section of the polarizer and its The exposed part (6) covered by the transparent substrate (1) is covered with an organic and/or inorganic sealing material (5) for blocking contact with air. The sealing material is formed on the peripheral area of the polarizing plate, and for example, when the polarizing plate is quadrangular, the sealing material covers all four sides.

When the polarizing film is larger than the transparent substrates (1) and (2), as shown in Fig. 10, it is necessary to cover the exposed portion, including part of the transparent substrate, with a sealing material. When the polarizing film is smaller than the transparent substrates (1) and (2), as shown in FIG. 3, the same effect can be obtained by covering only the cross-section of the polarizing film. In addition, as shown in FIG. 12, a structure in which a spacer (7) is sandwiched between transparent substrates (1) and (2), and the spacer (7) has the same thickness and ratio as the polarizing film is also effective. The size of the polarizing film is slightly larger, and the gap between the spacer and the polarizing film is filled with a sealing material.

In the case of a polarizing film having a protective film on only one surface of the polarizer, sealing is performed in a similar manner to the structure having protective films on both surfaces of the polarizer. For example, FIG. 11 shows a structure with a protective film on both surfaces of the polarizer, and FIG. 13 shows a structure with a protective film on one surface thereof.

When the exposed portion of the polarizing film exists in the space surrounded by the transparent substrate and the polarizing film on both sides (FIG. 11 and FIG. 13), the sealing material can be absorbed by the above-mentioned concave portion and/or hole portion of the transparent substrate. Filling into this space (for example, Figure 22), and when there is no such part, even if the sealing material is directly filled into this space, the sealing material will flow to the exposed part due to capillary phenomenon to get covered (Figure 24) .

A polarizing plate with a protective film in which a transparent substrate pasted to the polarizer is made of a material having non-optical anisotropy will be described below.

In the case of the structure shown in Figure 15, that is, if the polarizing film is smaller than the transparent substrate (2), and the transparent substrate (1) is smaller than the polarizing film, then the part of the polarizing film that contacts the air, specifically the cross section of the polarizing film And the surface (6) not covered by the transparent substrate (1) is covered with an organic and/or inorganic sealing material (5) for blocking contact with air. The sealing material is generally formed in the peripheral region of the polarizing plate, and for example, when the polarizing plate is quadrilateral, the sealing material covers all four sides.

When the polarizing film is larger than the transparent substrates (1) and (2), as shown in Figure 16, it is necessary to cover the cross-section and surface of the polarizing film, including the partially transparent substrate, with a sealing material.

Furthermore, when the polarizing film is smaller than the transparent substrates (1) and (2), as shown in FIG. 17, the same effect can be obtained by covering only the cross-section of the polarizing plate.

In addition, as shown in FIG. 18, a structure in which a spacer (7) is sandwiched between transparent substrates (1) and (2), and the spacer (7) has the same thickness and ratio as the polarizing film is also effective. The slightly larger size of the polarizing film, the gap between the spacer and the polarizing film is filled with a sealing material. In addition, in the case of a polarizing film having a protective film on both surfaces of the polarizer, it is equally effective as in the case of having a protective film on only one surface of the polarizer.

The structural elements of the polarizing plate of the present invention will be described below.

(polarizer)

As the polarizer of the present invention, one obtained by allowing a dichroic dye or iodine to be absorbed or oriented in a polarizer substrate such as polyvinyl alcohol resin, polyvinyl acetate resin, ethylene/ Vinyl acetate resin (EVA), polyamide resin, polyester resin, etc.

Here, the polyvinyl alcohol contained in the polyvinyl alcohol resin is a partially or completely saponified polyvinyl acetate; , unsaturated carboxylic acids of methacrylic acid and maleic acid, unsaturated sulfonic acids, vinyl ether, etc.) saponified substances of copolymers, such as saponified EVA resins, etc.; obtained by modifying polyvinyl alcohol with aldehydes Polyvinyl formal and polyvinyl acetal, etc. As the polarizer base material, from the viewpoint of dye absorption and alignment characteristics, a film made of polyvinyl alcohol resin, especially a film made of polyvinyl alcohol itself, can be used.

As the material to be absorbed on the polarizer substrate and aligned therein, a dichroic dye is preferable from the viewpoint of light resistance. By using different wavelength-dependent dyes, it is possible to manufacture polarizers for the blue, green and red channels of a projection-type liquid crystal display.

As a dichroic dye, as described in "development of dichroic coloring matter for liquid crystal display" (Ekisho hyojisouchiyo nishokusei shikiso no kaihatsu) (Kayane et al., Sumitomo Chemical Co. , Ltd., 2002-II, pp. 23 to 30).

The dichroic dyes of formula (I) in free acid form are specifically mentioned:

(Wherein, Me represents a metal atom selected from copper atom, nickel atom, zinc atom and iron atom, A ¹ represents an optionally substituted phenyl group or an arbitrarily substituted naphthyl group. B ¹ represents an optionally substituted The naphthyl group, and an oxygen atom bonded to Me and an azo group represented by -N=N- are connected to the carbons located in the ortho positions of the benzene ring. ^{R 1} and R ² are each independently Indicates an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a carboxyl group, a sulfoxy group, a sulfoneamide group, a sulfonealkylamide (sulfonealkylamide) group, amino group, amide group, halogen atom or nitro group)

Also mentioned are dichroic dyes of formula (II) in free acid form:

(wherein, A ³ and B ³ each independently represent an optionally substituted phenyl group or an optionally substituted naphthyl group. ^{R 3} and R ⁴ each independently represent a hydrogen atom, and those having 1 to 4 carbon atoms An alkyl group, an alkoxy group having 1 to 4 carbon atoms, a carboxyl group, a sulfoxy group, a sulfoneamide group, a sulfonealkylamide group, an amino group, a halogen atom or a nitro group group, m represents an integer of 0 or 1)

Also mentioned are dichroic dyes of formula (III) in free acid form:

Q ¹ -N=NQ ² -XQ ³ -N=NQ ⁴ (III)

(Wherein, Q ¹ and Q ⁴ each individually represent an optionally substituted phenyl group or an optionally substituted naphthyl group, X represents a divalent residue of chemical formula (III-1) or chemical formula (III-2) , Q2 and Q3 each independently represents an optionally substituted phenylene group).

-N＝N- (III-1)

Also mentioned are dichroic dyes of formula (IV):

(wherein Me represents a metal atom selected from a copper atom, a nickel atom, a zinc atom and an iron atom, each of ^Q and ^Q independently represents an optionally substituted naphthyl group, and an oxygen atom bonded to Me and one with-

-N=N- (IV-1)

The nitrogen-containing groups represented by N=N- are attached to carbons located at mutual ortho positions on the benzene ring. Y represents a divalent residue of chemical formula (IV-1) or chemical formula (IV-2), Q ⁵ and Q ⁶ each independently represent a hydrogen atom, an alkyl group with 1 to 4 carbon atoms, an alkyl group with 1 to 4 carbon atom alkoxy group or thiooxy group)

Mention is also made of dichroic dyes represented by the Color Index Generic Names selected from C.I. Direct Yellow 12, C.I. Direct Red 31, C.I. Direct Red 28, C.I. Direct Yellow 44, C.I. Direct Yellow 28, C.I. Direct Direct Red 79, C.I. Direct Red 2, C.I. Direct Red 81, C.I. Direct Orange 26, C.I. Direct Orange 39, C.I. Direct Red 247, and C.I. Direct Yellow 142.

Dichroic dyes can be used in free acid form or as amine salts such as ammonium salts, ethanolamine salts, alkylamine salts, etc., usually in the form of basic metal salts such as lithium salts, sodium salts, potassium salts, etc. .

These dichroic dyes may be used each alone or in combination of two or more.

As for the method of manufacturing the polarizer, the following method is exemplified.

First, a dichroic dye is dissolved in water to provide a concentration of about 0.0001 to 10% by weight to prepare a dye bath. Dyeing auxiliaries may be used if necessary, for example, a method of using Glauber's salt at a concentration of 0.1 to 10 wt% in the dye bath is suitable.

In the dyebath thus prepared, the polarizer substrate is immersed and dyed. The dyeing temperature is preferably from 40 to 80°C. The dyes are oriented by stretching the polarizer substrate before it is dyed or the polarizer substrate is dyed. As for the dyeing method, for example, there can be mentioned stretching methods such as wet or dry.

In order to improve the light transmittance, degree of polarization, and light resistance of the polarizer, post-treatment such as boric acid treatment or the like may be performed. In the acid treatment, generally use 1 to 15wt%, preferably 5 to 10wt% boric acid aqueous solution in the concentration range, and immerse the polarizing film substrate in the temperature range of 30 to 80°C, preferably 50 to 80°C, but can Varies depending on the kind of polarizer substrate and dye used. In addition, if necessary, fixing treatment may be performed simultaneously with an aqueous solution containing a cationic polymer compound.

In the present invention, the water content of the polarizer included in the polarizing plate is preferably 5 wt% or less, more preferably 1 wt% or less. In the case of manufacturing a polarizer by adding a dichroic dye to PVA, when the water content is less than or equal to 5 wt%, the decomposition of the dye can be significantly suppressed and the light resistance of the obtained polarizer can be significantly improved.

The specific method used to measure the moisture content of the polarizer is a method of calculating the percentage of weight loss obtained after drying with a stream of air at 130° C. for 30 minutes under polarizer exposure conditions.

For example, the weight (W1) of the polarizer and the weight (W2) of the polarizer obtained by drying at 130° C. for 30 minutes with an air flow under the polarizer exposure condition were measured, and the ratio of the two was calculated by the following formula:

(Water content, %)=[(W1-W2)/W1]×100

(Sealing material)

As for the sealing material used in the polarizing plate of the present invention, the following resins are exemplified, which exhibit fluidity during processing and are cured after processing to exhibit a sealing function, such as ultraviolet curable resins and thermosetting resins. Resins, and resins cured by these two effects, etc.

When a sealing material exhibiting fluidity during handling is used, the viscosity of the resin before curing is 20 Pa·s or less, preferably 0.01 Pa·s or more and 5 Pa·s or less. By using a resin with a viscosity of 20 Pa·s or less, the time required for sealing can be shortened because of its high fluidity, and by using a resin with a viscosity of 0.01 Pa·s or greater, it is possible to prevent the sealing material from flowing onto the transparent substrate or external. Here, the viscosity is a value measured by JIS K 6249.

The content of volatile components in the sealing material before curing is preferably less than or equal to 2 wt%, more preferably less than or equal to 1 wt%. When the content of the volatile component is less than or equal to 2wt%, the generation of tiny air bubbles in the sealing material can be suppressed, and the sealing material can be coated under reduced pressure, thereby significantly improving productivity.

The glass transition temperature after curing of the preferred sealing material is greater than or equal to 80°C, more preferably about 120 to 200°C, the preferred boiling water absorption coefficient is less than or equal to 4wt%, more preferably less than or equal to 2wt%, further preferably less than or equal to 1 wt%. By using a sealing material having such a glass transition temperature, the heat resistance can be improved, and the penetration of moisture in the air into the polarizer can be suppressed, thereby improving the light resistance of the obtained polarizer.

Here, the boiling water absorption coefficient represents the percentage by weight of an increase in the solidified substance after entering boiling water for 1 hour compared to the weight of the solidified substance before immersion, which is obtained according to JIS K 6911.

When the sealing material is laminated between the transparent substrate and the polarizer, as shown in FIGS. Equal to 93%. Preferably, the transmittance is greater than or equal to 90%, because the attenuation of the transmitted light is small, the utilization rate is improved, and the brightness of the screen in the actual device installed with the polarizer is improved.

Examples of sealing materials satisfying the above viscosity conditions and transmittance conditions include polyolefin-based adhesives such as ethylene-acid anhydride copolymers (for example, BYNEL (registered trademark, Dupont)) and the like, epoxy resin-based adhesives, etc. (For example, epoxy resin EP582 manufactured by CEMEDING CO.Ltd., UV curable epoxy resin KR695A manufactured by ADEKA, UV curable epoxy resin XNR5542 manufactured by Nagase Chemtex Corporation), polyurethane resin-based adhesive, phenolic resin-based adhesive heat-curable adhesives such as mixtures, and silicone resins (for example, UV-curable resins FX-V550 and FX-V-540 manufactured by ADEKA, UV-curable silicone resins, silicone RTV, silicone rubber, with UV-curable adhesives such as polyether-modified silicone resins with silyl-terminated groups), cyanoacrylate adhesives, acrylic resins, and the like.

When the thickness is 100 μm, under the condition that the ambient temperature is 40°C and the relative humidity is 90%, the water vapor transmission rate of the sealing material after curing is preferably less than or equal to 60g/m ² ·24 hours, more preferably less than or Equal to 25 g/m ² ·24 hours. In this way, intrusion of moisture in the air into the polarizer can be suppressed, and the light resistance of the obtained polarizer can be improved. The water vapor transmission rate represents the amount of water passing through a solidified substance per ¹ m2 of cross section within 24 hours, and it is measured according to JIS Z 0208.

(transparent substrate)

The materials constituting the two transparent substrates of the polarizer of the present invention are usually inorganic transparent materials, specifically exemplified as silicate glass, borosilicate glass, titanosilicate glass, fused silica (quartz glass), quartz crystal, sapphire, YAG (yttrium-aluminum-garnet) crystals, fluorite, etc. Silicate glass is marketed as white glass or blue glass for optical materials.

A preferred embodiment of the invention is such that at least one of the transparent substrates is made of a material having a thermal conductivity greater than or equal to 5 W/mK. When the thermal conductivity is greater than or equal to 5W/mK, the heat generated in the polarizer can be effectively released into the substrate to reduce the temperature of the polarizer, thereby improving the light resistance of the polarizer. Examples of materials having a thermal conductivity greater than or equal to 5 W/mK specifically include quartz crystals, sapphires, and YAG crystals.

Regarding the specific combination of the materials of the two transparent substrates constituting the polarizer of the present invention, from the viewpoint of suppressing costs, it is more preferable that one transparent substrate is made of sapphire or quartz crystal with high thermal conductivity, and the other substrate is made of quartz crystal, fused silica, Made of silicate glass or borosilicate glass.

The thickness of the transparent substrate is preferably 0.05 mm to 3 mm, more preferably 0.08 to 2 mm, from the viewpoint of industrial production and size matching with an applied projector optical system. The thickness is preferably greater than or equal to 0.05 mm, because that can suppress glass breakage during handling and achieve stable production. The thickness is preferably less than or equal to 3 mm, since that enables miniaturization and weight reduction of the resulting polarizing plate.

Anti-reflection treatment corresponding to the wavelength of light to be used needs to be performed on the surface of the transparent substrate attached to both surfaces of the polarizer that is in contact with the air. As for the antireflection treatment, for example, a method of using a dielectric multilayer film formed by a spin coating method or a vacuum evaporation method, a method of applying one or more low-refractive index layers by coating, and the like are mentioned. In addition, an antifouling treatment for preventing stain adhesion on the surface is performed on the antireflection surface. This can be done, for example, by applying to the surface a thin film layer comprising an amount of fluorine which hardly affects the antireflection properties.

(protective film)

The polarizing film of the present invention includes a protective film in addition to the polarizer. When the polarizing film includes a protective film, the polarizing film is obtained by pasting the protective film on one or both surfaces of the polarizer. It is preferable to stick a protective film on the polarizing film, because that can improve the mechanical strength of the polarizing film and the handleability (hard to break) of the polarizing film in production.

When the protective film is attached to both surfaces of the polarizer, the heat generated by the polarizer is conducted to the transparent substrate through the protective film, so it is preferable to attach the protective film to only one surface of the polarizer from the viewpoint of improving light resistance.

The protective film mentioned is an acetyl cellulose film (TAC film) such as a triacetyl cellulose film, etc., a polyester resin film, an olefin resin film (for example, a product commercially available under the trade name ZEONOR of ZEON Corporation, and JSR's company registered trade name is ARTON), polycarbonate resin film, polyether ether ketone resin film, polysulfone resin film, etc. Among them, films and olefin resin films composed mainly of triacetyl cellulose are preferable, and films composed of triacetyl cellulose as a main component are particularly preferable.

The thickness of the protective film is preferably 10 to 90 μm, more preferably 10 to 45 μm. The thickness is preferably less than or equal to 90 μm because the thickness of the polarizing film can be reduced, and the thickness is preferably greater than or equal to 10 μm because the strength of the polarizing film can be secured.

When the polarizing film includes a protective film, the water content of the polarizing film is less than or equal to 1.6 wt%, preferably less than or equal to 1.2 wt%, because light resistance can be improved.

Here, the water content of the polarizing film is the weight of water based on the total weight of the polarizing film including the polarizer and the protective film, the adhesive for pasting the polarizing film and the transparent substrate, and the sealing material. Generally, the amount of adhesive and sealing material is small, and the water content is small, but since the amount of the protective film is about 4wt%, the water content of the polarizing film containing it should be controlled to be less than or equal to 1.6wt%. , preferably less than or equal to 1.2 wt%.

The water content of the polarizing film is expressed as the weight loss obtained by drying the polarizing film at 130°C with an air stream for 30 minutes under the polarizing film exposure condition and the polarizing film including the polarizer and the protective film, and the adhesive for sticking the polarizing film and the transparent substrate , and the ratio of the total weight of the sealing material.

For example, the weight (WF1) of the polarizer measured by peeling off the transparent substrate of the polarizer, etc. to expose the polarizing film, the weight (WF2) measured by drying with an air stream at 130°C for 30 minutes and the weight (WF2) measured respectively The weight of the transparent substrate on both sides, and then calculate the ratio by the following formula:

(Water content, %)=[(WF1-WF2)/(WF1-WF0)]×100

Also when the polarizing film includes a protective film, preferably at least one of the protective films is made of a material having a thermal conductivity greater than or equal to 5 W/mK, more preferably the material of one transparent substrate is quartz crystal or sapphire, and the material of the other substrate is quartz Crystal, quartz glass, silicate glass or borosilicate glass. As for the polarizing plate, those in which a resin layer is formed between a transparent substrate made of a material having a thermal conductivity of 5 W/mK or more and the polarizer, and the total thickness of the resin layer is 0.1 μm or more and Polarizers smaller than 10 μm.

(Transparent substrate made of material with non-optical anisotropy)

When the polarizing film includes a protective film, the polarizing film is composed of a polarizer and a protective film, and a polarizing plate is formed by pasting transparent substrates on both surfaces of the polarizing film, when the transparent substrate pasted to the polarizer is made of a When the transparent substrate is made of an optically anisotropic material, the contrast of the image obtained when used in a projection liquid crystal display can be increased. That is, this case is preferred.

Here, the term "having non-optical anisotropy (referred to as retardation in some cases)" means that there is substantially no phase difference between two light beams having different polarization directions among light beams passing through the transparent substrate. By using a transparent substrate "with non-optical anisotropy" as the transparent substrate pasted to the polarizer, the polarization plane produced by light passing through the polarizer from the light source is not distorted by the transparent substrate with non-optical anisotropy. Therefore, this use is preferred.

Specific examples of the material of such a transparent substrate include silicate, borosilicate glass, and the like.

The transparent substrate attached to the protective film may or may not have optical anisotropy because incident light passes through the substrate before passing through the polarizer. In order to improve the light resistance of the polarizer, the material of the transparent substrate attached to the protective film is preferably a material having a thermal conductivity greater than or equal to 5 W/mK, more preferably quartz crystal or sapphire, especially preferably sapphire.

(resin layer)

The polarizing plate of the present invention is a polarizing plate having a transparent substrate on both surfaces of a polarizing film including a polarizer, wherein at least one resin layer generally exists between the polarizing film and the transparent substrate.

For example, as shown in FIG. 1 , the resin layers (a) and (c) are resin layers formed between the transparent substrate and the polarizing film, and the resin layers are in direct contact with the transparent substrate.

In the present invention, a preferred embodiment is a polarizing plate having transparent substrates on both surfaces of the polarizer, wherein at least one of the transparent substrates is made of a material having a thermal conductivity of 5 W/mK or higher, and the polarizer is not The exposed portion covered by the transparent substrate is covered with resin.

In the present invention, a preferred embodiment is a polarizing plate having a laminated structure of two or more layers of resin including an adhesive layer between the polarizer and at least one transparent substrate. Hereinafter, this portion is referred to as a laminated portion in some cases, for example corresponding to resin layers (b) and (c) in FIG. 1 . The adhesive layer included in the laminated portion is a resin layer that directly contacts the transparent substrate among the resin layers forming the laminated portion, and corresponds to the resin layer (c) in FIG. 1 . The resin layer (b) also has an adhesive function, but has a high mechanical strength and thus has a function of protecting the polarizer. When a laminated portion is formed between the polarizing film and the transparent substrate, the mechanical strength of the polarizer can be increased even without using a protective film, and problems such as cracking during the production of the polarizing plate can be suppressed, and in actual use Can improve the light fastness of the polarizer. That is, such a structure is preferable.

The total thickness of the laminated portion is preferably greater than or equal to 1 μm and less than or equal to 30 μm, more preferably greater than or equal to 1 μm and less than or equal to 10 μm. The thickness is preferably greater than or equal to 1 [mu]m, since then the strength of the resin film can be secured and the production of the resin film can be facilitated, and a sufficiently large adhesive force to the transparent substrate can be secured. The total thickness of the laminated portion is preferably less than or equal to 30 μm, because it can easily conduct heat generated in the polarizer to the transparent substrate, thereby reducing the temperature of the polarizer and improving light resistance.

In the present invention, an ultraviolet curable resin or a heat curable resin may be used in the laminated portion. Especially suitable for use with UV curable resins, since high temperature conditions are not required during the curing process, thus not degrading the optical properties of the polarizer.

The content of the volatile components before curing of the curable resin forming the laminated portion is preferably 2 wt% or less, more preferably 1 wt% or less. When the content of the volatile component is less than or equal to 2 wt%, the generation of micro bubbles in the processed resin layer can be suppressed, and the resin layer can be applied under reduced pressure, thereby improving productivity. The viscosity of the resin layer before curing is preferably greater than or equal to 0.01 Pa·s and less than or equal to 20 Pa·s at 25°C. The viscosity of the resin layer is preferably less than or equal to 20 Pa·s, because that ensures satisfactory fluidity, flatness of the resin, and shortens the production time of the polarizing plate.

The light transmittance of the resin layer to be formed in the polarizer in the wavelength range of 400 nm to 700 nm is preferably greater than or equal to 90%, more preferably greater than or equal to 93%, when the cured thickness is 25 μm. The light transmittance is preferably greater than or equal to 90%, because then the attenuation of the transmitted light is small, the use efficiency is improved, and the brightness of the screen is improved when the polarizing plate is installed on a projection type liquid crystal display.

The resin layer other than the adhesive layer contained in the laminated portion has a main function of protecting the polarizer, and in this case, the protective film is not necessary. Such a resin layer corresponds to, for example, the resin layer (b) in FIG. 1 . The glass transition temperature of the resin layer is preferably greater than or equal to 40°C, more preferably greater than or equal to 60°C. The glass transition temperature of the resin layer is preferably greater than or equal to 40° C., because it can ensure the strength of the polarizer especially in the dyeing process of the polarizer manufacturing process, suppress the problem of polarizer cracking, etc., and lead to an increase in yield. In the resin layer, any one of acrylic ultraviolet curing resin, silicone-based ultraviolet curing resin, epoxy-based ultraviolet curing resin and epoxy-based thermosetting resin can be used, and acrylic ultraviolet curing resin or acrylic ultraviolet curing resin is more preferably used in the resin layer. Silicone UV curing resin, because that can further improve the light resistance of the polarizer.

As shown in FIGS. 4 to 6 , a sealing material is included in the resin film forming the laminated portion. In this case, the sealing material also functions as an adhesive layer for bonding the transparent substrate and the resin layer.

In the polarizing plate of the present invention, when the polarizer is bonded via a resin layer to a transparent substrate having a thermal conductivity greater than or equal to 5 W/mK, the thickness of the resin layer is preferably greater than or equal to 0.1 μm and less than or equal to 10 μm, More preferably, it is greater than or equal to 0.1 μm and less than or equal to 5 μm. The thickness is preferably greater than or equal to 0.1 μm, since then a sufficiently large adhesive force between the transparent substrate and the transparency can be ensured. The thickness is preferably less than or equal to 5 μm, because it is easy to conduct the heat generated by the polarizer to the transparent substrate with a thermal conductivity greater than or equal to 5W/mK showing high heat release capability, thereby reducing the temperature of the polarizer and further improving light resistance.

The resin layer formed in this case may be a single layer consisting of only an adhesive layer, or a composite layer consisting of two or more layers of several resins.

(Manufacturing method)

The polarizing plate of the present invention, that is, a polarizing plate having a transparent substrate on both surfaces of a polarizing film comprising a polarizer, wherein the containing portion of the polarizing film not covered by the transparent substrate is covered with a sealing material, can be obtained by performing the following The above process manufacturing: performing the process of bonding the transparent substrate to both surfaces of the polarizing film with resin and drying the polarizing film, and then performing the process of covering the exposed portion of the polarizing film not covered by the transparent substrate with a sealing material.

Here, a protective film is generally pasted on a polarizer before use in polarizer manufacturing to protect a polarizer having low mechanical strength, thereby preventing it from cracking during the polarizer manufacturing process. However, the protective film hinders heat conduction from the polarizer to the transparent substrate. Therefore, the present invention has intensively studied a method for manufacturing a polarizing plate that does not use a protective film and that does not crack the polarizer when manufactured. As a result, the inventors of the present invention found that cracking of the polarizer can be prevented if a thin resin layer less disturbing to heat conduction than a protective film is formed on at least one surface of the polarizer. With the above-described preferable production method without using a protective film according to the present invention, stable productivity can be secured, and industrial production can be performed to produce a polarizing plate having particularly high light resistance. A particularly preferable manufacturing method is the following method for manufacturing a polarizing plate, wherein a resin layer is formed on one surface of a polarizing film composed of a polarizer, then the resin layer is bonded to a transparent substrate, and after drying, the second Two transparent substrates are bonded to the surface of the polarizing film to which the transparent substrates are not bonded, and the exposed portion of the polarizing film not covered by the transparent substrates is covered with a sealing material.

When the polarizing film includes a protective film, the protective film is pasted on the polarizing film before the polarizing film is bonded to the transparent substrate.

If the polarizing plate has no protective film but has a laminated portion composed of two or more laminated resin layers including an adhesive layer between the polarizing film composed of a polarizer and at least one transparent substrate , then before bonding the polarizing film and the transparent substrate via the resin layer, other resin layers other than the adhesive layer of the lamination portion are previously formed on the surface of the polarizing film.

When the transparent substrate and the polarizing film are bonded, it is preferable to form a resin layer as an adhesive layer and perform at least one process of setting an object under a reduced pressure condition before curing for manufacturing.

A more preferable manufacturing method is a method that, when drying, before bonding the polarizing film and the second transparent substrate (when resin layers are provided on both surfaces of the polarizing film, bonding via the resin layer) , The polarizing film is dried at less than or equal to 110°C.

That is, the polarizing film is dried in air at 110°C or less to control the water content of the polarizer to be less than or equal to 5 wt%. As for the drying temperature, a temperature range of 40 to 110°C is preferable, and a temperature range of 50 to 100°C is more preferable. The drying process may be carried out at a stage where the transparent substrate is not bonded to the polarizer at all or at a stage where the transparent substrate is bonded to one side or both sides of the polarizing film, drying under the condition that the transparent substrate is bonded to one side or both sides of the polarizing film It is more preferable because the flatness of the polarizing film can be maintained and the water in the polarizing film can be quickly removed from one layer of the unbonded transparent substrate. Furthermore, in this case, there is also an advantage in that there is no intrusion of water from the transparent substrate side, and it is easy to keep the polarizer in a dry condition. When the polarizing plate has a laminated portion composed of two or more laminated resin layers, wherein the laminated resin layer includes an adhesive layer between the polarizer and at least one transparent substrate, preferably under such conditions Drying was performed in which the transparent substrate was bonded to one side of the polarizing film, and the resin layer was formed on the other side where the transparent substrate was not bonded. In this case, the occurrence of cracking of the polarizer during drying can be prevented, thereby improving productivity.

As for the drying method, there are, for example, a heat drying method, a reduced pressure drying method, and the like. As specific examples of the heat drying method, there are, for example, a method of placing in a heating furnace, a method of irradiating a polarizing plate with light, and spontaneous heat generation of a polarizing plate utilizing light absorption of a polarizer, and other methods. In a large-scale process, a heat drying method using a heating furnace or light irradiation is preferable from the viewpoint of simplification of the apparatus.

If the transparent substrates are bonded after the drying process, and then the exposed portion of the polarizing film not covered by the transparent substrate is covered with a sealing material and cured, the polarizing plate of the present invention can be completed.

Here, if at least one of the transparent substrates has a recessed portion and/or a hole portion for injecting the sealing material, and the sealing material is injected through the recessed portion and/or the hole portion, the exposed portion of the polarizing film can be quickly covered by a capillary phenomenon. .

For example, if the hole portion is located approximately near the center of the top of the transparent substrate, as shown in FIG. 21, according to the assembly diagram shown in FIG. The depressed portion is moved to an exposed portion having a height of about 10 μm to 300 μm provided by the transparent substrate on both sides and a depth of about 0.5 mm to 20 mm from the outer edge of the transparent substrate to the polarizing film, and the sealing material is as follows The curing, then, can obtain a polarizing plate having a cross-section as shown in FIG. 3 . The size of the hole portion is about 0.01 to 2 mm.

If the depressed portion is approximately at the center of one side of the transparent substrate, as shown in FIG. 23, the sealing material is filled in the depressed portion in a similar manner, so that a polarizing plate having a cross section as shown in FIG. 3 can be obtained. As for the shape of the concave part, in addition to the Japanese katakana "コ" shape as shown in Figure 23, U-shape, triangle, semicircle, etc. are also mentioned. As for the size of the concave portion, the size of the largest concave portion is controlled to be about 0.01 to 2mm.

Provide the desired number of recessed parts and hole parts to sufficiently cover the exposed part surrounded by the polarizing film and the transparent substrate on both surfaces with the sealing material, one or more recessed parts on one side, or one highest point A hole section.

The depressed portion and the hole portion may exist on the transparent substrate at the same time. The depressed portion and the hole portion can be formed on the transparent substrate by using a diamond tool or a laser optical processing device.

(Structure of projector)

The polarizing plate of the present invention is used, for example, in a projection type liquid crystal display (projector). The components of the rear projector optical system shown in FIG. 25 will be explained as an example. The polarizing plate of the present invention is exemplified by 142 and 143 in FIG. 25 .

The brightness of the light beam from the high-pressure mercury lamp 111 as the light source is first uniformized, and then polarized with the cross section of the opposite light beam by the first lens array 112, the second lens array 113, the polarization conversion unit 114 and the stacking lens 115.

Specifically, the light beam emitted by the light source 111 is divided into a plurality of micro-beams by the first lens array 112 having micro-lenses 112a arranged in a matrix. The second lens array 113 and the superposition lens 115 are arranged such that each sub-beam irradiates all three LCD panels 140R, 140G, and 140B as irradiation objects. With this configuration, all the surfaces on the incident side of each LCD panel exhibit approximately uniform illuminance.

The polarization conversion element 114 is typically formed by an array of polarizing beam splitters and is arranged between the second lens array 113 and the stacking lens 115 . It plays the role of pre-converting any polarized light emitted by the light source into polarized light with a specific polarization direction, and reduces the light loss at the incident side polarizer described later, thereby improving the brightness of the screen.

Brightness homogenization and polarized light pass through a reflection mirror (reaction mirror) 122, and then are divided into red light channel, green light channel, and blue light channel by dichroic mirrors 121, 123 and 132 for separating into RGB three primary colors, and enter respectively LCD panels 140R, 140G and 140B.

For the LCD panels 140R, 140G, and 140B, a polarizing plate (incident side) 142 and a polarizing plate (exiting side) 143 of the present invention are provided on the incident side and the outgoing side, respectively.

Two polarizing plates sandwiching a liquid crystal panel in the respective RGB optical paths provided on the incident side and the outgoing side will be described below. The incident-side polarizing plate and the output-side polarizing plate located in each optical path are arranged in a structure in which their absorption axes intersect, and serve as polarization states that will be controlled by image signals for each pixel in the LCD panels 140R, 140G, and 140B located in each optical path The effect of converting to the amount of light.

The polarizing plate of the present invention has the same structure in all the light paths of the blue light channel, the green light channel and the red light channel, and can be effectively used as a polarizing plate excellent in durability in each light path, wherein, in the blue light channel and the green light channel is especially effective in

Optical images generated by incident light with different transmission factors corresponding to the pixels according to the image data of the LCD panels 140R, 140G, and 140B are combined by the cross dichroic prism 150 , then enlarged by the projection lens 170 and projected onto the screen 180 .

The polarizing plate of the present invention is suitable for projection type liquid crystal displays such as front projectors, rear projectors, etc., and exhibits a long service life especially when used in projection type liquid crystal displays with high brightness due to excellent light resistance. Furthermore, according to the manufacturing method of the present invention, the polarizing plate of the present invention is easy to manufacture, and thus the present invention has outstanding applicability in industry.

Example

The present invention will be described below based on the following examples, but the present invention should not be construed as being limited to these examples.

(Example 1)

A polyvinyl alcohol film (VF-PX manufactured by Kuraray Co., Ltd., hereinafter referred to as PVA) was uniaxially stretched, dyed with a blue-absorbing dye, and dried to obtain a film for the blue light channel of a projector. The polarizer has a polarization degree of 99.9% and a transmittance of 44.0% for light with a wavelength of 440 nm when the thickness of the polarizer is 28 μm. The polarizer was attached to a sapphire substrate (manufactured by Kyocera Corporation) having a thickness of 0.5 mm and a thermal conductivity of 40 W/mK with an acrylic ultraviolet curing adhesive (MO5 manufactured by Adell) under reduced pressure. At this stage, the adhesive layer had a thickness of 5 μm. Subsequently, a silicone-based ultraviolet curable resin (FXV550 manufactured by ADEKA) was applied and cured on the upper surface of the polarizer to form a 10 μm thick resin layer. While maintaining this condition, the layer was dried in a 50°C oven for 72 hours to control the moisture content of the polarizer to be less than or equal to 1.2 wt%. After drying, the upper surface of the resin layer and the blue plate glass (sapphire glass) were pasted with an acrylic ultraviolet curable resin (MO5 manufactured by Adell) under reduced pressure. At this stage, a laminated structure is formed between the blue plate glass and the polarizer with a thickness of 15 μm. After that, heat-curable epoxy resin (EP582 manufactured by CEMEDINE Co., Ltd., water vapor transmission rate: 20 g/m ² ·24 hr) was applied as a sealing material under reduced pressure to cover the exposed portion of the polarizer , and cured to obtain a polarizer with the same structure as the schematic diagram in Figure 1. On the surface of the sapphire substrate and the blue plate glass used to contact the air, 5 layers of vacuum-evaporated dielectric substances are used for anti-reflection treatment.

The polarizing plate obtained in this way is arranged in the optical path of the blue light channel in the light fastness evaluation device as shown in Figure 26, and the time for inspection to find that light leakage occurs due to deterioration is 80 to 120 hours (hereinafter, referred to as this in some cases) assessment is the initial assessment). In addition, the obtained sample was left for 72 hours at an ambient temperature of 60° C. and a relative humidity of 90%, after which its light resistance was evaluated in the same manner, and it was found that no light leakage occurred (hereinafter, this evaluation is referred to in some cases as long-term evaluation).

The light resistance evaluation device used in this program uses a 130W high-pressure mercury lamp manufactured by Phillips as a light source, and has the same optical system as a rear projection TV, such as a polarizing beam splitter array and a lenticular lens, etc., and the amount of light irradiated to the polarizer It is 3.0W per 1cm ² .

Here, light leakage is a phenomenon in which the transmittance along the absorption axis increases after the polarizing plate is set in the optical path of the light resistance evaluation device. When the polarizer as the evaluation object is set in the Cross-Nicole mode with the standard polarizer, basically the transmittance should be lowered, but light leaks and is transmitted in this case, so this phenomenon is called "light leakage". ".

(Example 2)

The polarizer obtained in the same manner as in Example 1 was stuck to a sapphire substrate (manufactured by Kyocera Co. manufacturing) on. At this stage, the adhesive layer had a thickness of 5 μm. Subsequently, a silicone-based ultraviolet curable resin (FXV550 manufactured by ADEKA) was applied and cured on the upper surface and side surfaces of the polarizer to form a 5 μm thick resin layer. While maintaining this condition, the layer was dried in a 60°C oven for 24 hours to control the moisture content of the polarizer to be less than or equal to 1.2 wt%. After drying, paste the upper surface of the resin and the quartz crystal with a thermal conductivity of 8 W/mK with an epoxy-based ultraviolet curing resin (KR695A manufactured by ADEKA, water vapor transmission rate: 50 g/m ² 24 hr) under reduced pressure , and at the same time, cover the side surface of the polarizer from above the substrate cured by the above-mentioned acrylic-based ultraviolet curable resin, to obtain a polarizer having a structure as shown in FIG. 5 . At this stage, a laminated structure is formed between the quartz crystal and the polarizer with a thickness of 10 μm. On the surface of the sapphire substrate and the quartz crystal used to contact the air, anti-reflection treatment is performed with 5 layers of vacuum-evaporated dielectric substances.

The polarizing plate thus obtained is arranged in the light path of the blue light channel in the light resistance evaluation device as shown in Figure 26, and the time for inspection to find that light leakage occurs due to deterioration is 120 to 160 hours (hereinafter, referred to as this in some cases) assessment is the initial assessment). In addition, the obtained sample was left for 72 hours at an ambient temperature of 60° C. and a relative humidity of 90%, and then its light resistance was evaluated in the same manner, and it was found that no light leakage occurred.

(Example 3)

The polarizer obtained in the same manner as in Example 1 was attached to a quartz crystal having a thickness of 0.5 mm and a thermal conductivity of 8 W/mK with an acrylic ultraviolet curing adhesive (MO5 manufactured by Adell) under reduced pressure. At this stage, the adhesive layer had a thickness of 5 μm. Subsequently, a silicone-based ultraviolet curable resin (FXV550 manufactured by ADEKA) was applied and cured on the upper surface and side surfaces of the polarizer to form a 5 μm thick resin layer. While maintaining this condition, the layer was dried in a 70°C oven for 12 hours to control the moisture content of the polarizer to be less than or equal to 1.2 wt%. After drying, the resin and the upper surface of the quartz crystal were pasted with an acrylic UV-curable adhesive (MO5 manufactured by Adell) under reduced pressure. At this stage, a laminated structure is formed between the quartz crystal and the polarizer with a thickness of 10 μm. After that, heat-curable epoxy resin (EP582 manufactured by CEMEDINE Co., Ltd., water vapor transmission rate: 20g/ ^m2 ·24hr) was applied as a sealing material under reduced pressure to cure from the above-mentioned acrylic-based ultraviolet rays. The side surface of the polarizer is covered on the substrate after the resin is cured, and the polarizer having the same structure as in the schematic diagram of FIG. 2 is obtained after curing. On the surface of the quartz crystal used to contact the air, anti-reflection treatment is performed with 5 layers of vacuum-evaporated dielectric substances.

The polarizing plate obtained in this way is arranged in the optical path of the blue light channel in the light fastness evaluation device as shown in Figure 26, and the time for inspection to find that light leakage occurs due to deterioration is 40 to 80 hours (hereinafter, referred to as this in some cases) assessment is the initial assessment). In addition, the obtained sample was left for 72 hours at an ambient temperature of 60° C. and a relative humidity of 90%, and then its light resistance was evaluated in the same manner, and it was found that no light leakage occurred.

(Example 4)

The polarizer obtained in the same manner as in Example 1 was attached to a quartz crystal having a thickness of 0.5 mm and a thermal conductivity of 8 W/mK with an acrylic ultraviolet curing adhesive (MO5 manufactured by Adell) under reduced pressure. At this stage, the adhesive layer had a thickness of 5 μm. Subsequently, a silicone-based ultraviolet curable resin (FXV550 manufactured by ADEKA) was applied and cured on the upper surface and side surfaces of the polarizer to form a 5 μm thick resin layer. While maintaining this condition, the layer was dried in an oven at 80°C for 6 hours to control the moisture content of the polarizer to be less than or equal to 1.2 wt%. After drying, paste the upper surface of the resin layer and the blue plate glass with heat-cured epoxy resin (EP582 manufactured by CEMEDINE Company, water vapor transmission rate: 20g/m ² 24hr) under reduced pressure, and simultaneously remove from the above silicon The side surface of the polarizing plate was covered on the substrate cured by the ketone-based ultraviolet curable resin to obtain a polarizing plate having the structure shown in FIG. 5 . At this stage, a laminated structure is formed between the blue plate glass and the polarizer with a thickness of 10 μm. On the surface of the quartz crystal and the blue plate glass used to contact the air, anti-reflection treatment is performed with 5 layers of vacuum-evaporated dielectric substances.

The polarizing plate obtained in this way is arranged in the optical path of the blue light channel in the light resistance evaluation device as shown in Figure 26, and the time for inspection to find that light leakage occurs due to deterioration is 30 to 70 hours (hereinafter, referred to as this in some cases) assessment is the initial assessment). In addition, the obtained sample was left for 72 hours at an ambient temperature of 60° C. and a relative humidity of 90%, and then its light resistance was evaluated in the same manner, and it was found that no light leakage occurred.

(comparative example 1)

A sapphire substrate (manufactured by KYOCERA Corporation) having a thickness of 0.5 mm and a thermal conductivity of 40 W/mK was attached to the substrate obtained in the same manner as in Example 1 with an acrylic ultraviolet curing adhesive (MO5 manufactured by Adell) under reduced pressure. On one surface of the polarizer, a blue plate glass with a thickness of 0.5 mm was pasted on the other surface with an acrylic ultraviolet curable resin (M05 manufactured by Adell) without drying process to obtain a surface that was not covered with a sealing material on one side. Laminate (its construction is shown in Figure 7). At this stage, the adhesive layer had a thickness of 5 μm. The sides of the laminate have a configuration to be in contact with the air. On the surface of the sapphire substrate and the blue plate glass in contact with the air, 5 layers of vacuum-evaporated dielectric substances are used for anti-reflection treatment.

When the light fastness was evaluated in the same manner as in Example 1, light leakage due to deterioration of the polarizing plate occurred in only 8 to 15 hours in the initial evaluation stage, and furthermore, when the polarizing plate was at an ambient temperature of 60°C and a relative humidity of 90% When left to stand for 72 hours and then subjected to the same optical evaluation, deterioration progressed rapidly. The results are summarized in Table 1.

(comparative example 2)

A sapphire substrate (manufactured by KYOCERA Corporation) having a thickness of 0.5 mm and a thermal conductivity of 40 W/mK was attached to the substrate obtained in the same manner as in Example 1 with an acrylic ultraviolet curing adhesive (MO5 manufactured by Adell) under reduced pressure. on one surface of the polarizer. After that, a silicone-based ultraviolet curable resin (FXV550 manufactured by ADEKA) was applied and cured on the upper surface of the polarizer to form a 10 μm thick resin layer. The laminate was dried at 60°C for 24 hours, and then a quartz crystal having a thickness of 0.5 mm was pasted on the other surface with an acrylic ultraviolet curing resin (MO5 manufactured by Adell) to obtain a laminate in which one surface was not covered with a sealing material body (its structure is shown in Figure 8). At this stage, a laminated part is formed between the blue plate glass and the polarizer, and its thickness is 15 μm. In this configuration, this side of the laminate is in contact with the air. On the surface of the sapphire substrate and the quartz crystal in contact with the air, 5 layers of vacuum-evaporated dielectric substances are used for anti-reflection treatment.

When the light fastness was evaluated in the same manner as in Example 1, light leakage due to deterioration of the polarizing plate occurred in only 20 to 50 hours in the initial evaluation stage, and furthermore, when the polarizing plate was exposed to light at an ambient temperature of 60°C and a relative humidity of 90%. When the case was left for 72 hours and then subjected to the same light evaluation, deterioration progressed rapidly. The results are summarized in Table 1.

(Example 15)

The polarizer obtained in the same manner as in Example 1 was attached to sapphire having a thickness of 0.5 mm and a thermal conductivity of 40 W/mK with an acrylic ultraviolet curing adhesive (MO5 manufactured by Adell) under reduced pressure. At this stage, the adhesive layer had a thickness of 5 μm. While maintaining this condition, the layer was dried in an oven at 80°C for 6 hours to control the moisture content of the polarizer to be less than or equal to 1.2 wt%. After drying, the upper surface of the resin layer and the blue plate glass were pasted with an acrylic ultraviolet curing adhesive (MO5 manufactured by Adell) under reduced pressure. Subsequently, the sides of the polarizer were covered with a heat-curable epoxy resin (EP582 manufactured by CEMEDINE Corporation, water vapor transmission rate: 20 g/m ² ·24 hr) to obtain a polarizing plate having a configuration as shown in FIG. 7 . At this stage, a laminated structure is formed between the blue plate glass and the polarizer with a thickness of 15 μm. On the surface of the quartz crystal and the blue plate glass used to contact the air, anti-reflection treatment is performed with 5 layers of vacuum-evaporated dielectric substances.

The polarizing plate obtained in this way is arranged in the light path of the blue light channel in the light fastness evaluation device as shown in Figure 11, and the time for inspection to find that light leakage occurs due to deterioration is 80 to 120 hours (hereinafter, referred to as this in some cases) assessment is the initial assessment). In addition, the obtained sample was left for 72 hours at an ambient temperature of 60° C. and a relative humidity of 90%, and then its light resistance was evaluated in the same manner, and it was found that no light leakage occurred.

(Table 1)

Transparent Substrate Structure Transparent Substrate (A)/Transparent Substrate (B) The thickness of the laminated part The thickness of the adhesive layer (a)*1 Drying conditions Polarizer structure Lightfastness evaluation early stage long term Example 1 Sapphire/blue plate glass 15μm 5μm 60℃×24hr figure 1 80 to 120 hours ○ 2 Sapphire/Quartz Crystal 10μm 5μm 50℃×72hr Figure 5 120 to 160 hours ○ 3 Quartz crystal/quartz crystal 10μm 5μm 70℃×12hr figure 2 40 to 80 hours ○ 4 Quartz crystal / blue plate glass 10μm 5μm 80℃×6hr Figure 5 30 to 70 hours ○ 15 Sapphire/blue plate glass none 5μm 60℃×24hr Figure 7 90 to 120 hours ○ comparative example 1 Sapphire/blue plate glass none 5μm none Figure 8 8 to 15 hours × 2 Sapphire/Quartz Crystal 15μm 5μm 60℃×24hr Figure 9 20 to 50 hours ×

*1): Thickness of the laminated structure formed between the lens substrate (A) and the polarizer

(Example 5)

A uniaxially stretched polyvinyl alcohol film (VF-PX manufactured by Kuraray Corporation, hereinafter referred to as PVA), dyed with a blue-absorbing dye, was dried to obtain a polarizer for the blue light channel of a projector, and its thickness was 28 μm The degree of polarization for light with a wavelength of 440nm is 99.9%, and the transmittance is 44.0%. On both surfaces of the polarizer, an adhesive containing water-soluble polyamide epoxy resin (product name: Sumirez Resin 650) as an active ingredient of carboxyl group-modified polyvinyl alcohol resin (product name: KL318) was used. A cellulose acetate base film (KC8UY manufactured by Konic Corporation, hereinafter referred to as 8UYTAC) having a thickness of 80 μm was attached as a protective film to obtain a polarizing film. Paste sapphire glass (manufactured by Kyocera Corporation) with a thickness of 0.5 mm on one surface of the polarizing film obtained, and dry this layer in a heating oven at 70° C. for 180 minutes while maintaining the structure, so that the water content of the polarizing film is controlled to less than Or equal to 1.2 wt%. After drying, paste 0.1mm blue plate glass on another TAC surface. Afterwards, an ultraviolet curable resin is applied to cover the cross-section and exposed portion of the polarizer, and cured to obtain a polarizer having the same structure as the schematic diagram of FIG. 9 . On the surface of sapphire glass and blue plate glass used to contact the air, 5 layers of vacuum-evaporated dielectric substances are used for anti-reflection treatment.

The polarizing plate thus obtained was set in the light path of the blue light channel in the light resistance evaluation device shown in FIG. 26, and it was checked that the time for light leakage due to deterioration was 65 hours. In addition, the obtained sample was left for 72 hours at an ambient temperature of 60° C. and a relative humidity of 90%, and then its light resistance was evaluated in the same manner, and it was found that no light leakage occurred.

(Example 6)

On one surface of the polarizer (PVA) of the polarizing film obtained in the same manner as in Example 5, 8UYTAC was pasted with an epoxy-based adhesive, and an olefin resin film (registered trademark Zeonor, produced by ZEON) was pasted on the other surface. company, thickness 40μm), to obtain polarizing film. On the Zeonor side of the resulting polarizing film, sapphire glass (manufactured by Kyocera Corporation) with a thickness of 0.5 mm was pasted via an adhesive, and the layer was dried in an oven at 80° C. for 120 minutes to control the water content of the polarizing film to Less than or equal to 1.2 wt%. Next, paste 0.1mm blue plate glass on one side of 8UYTAC. After that, the sides of the resulting laminated portion were covered with an ultraviolet curable resin to obtain a polarizing plate having a structure as shown in FIG. 11 . On the air-contacting surface of sapphire glass and sapphire glass, 5 layers of vacuum-evaporated dielectric substances are used for anti-reflection treatment.

The same light resistance evaluation as in Example 5 was performed, and finally excellent initial evaluation was found, and no deterioration was found even in long-term evaluation. The results are summarized in Table 2 together with Example 5.

(Example 7)

On only one surface of the same polarizer (PVA) as in Example 1, a cellulose acetate film (KC4UY manufactured by Konica Corporation, hereinafter referred to as 4UYTAC) with a thickness of 40 μm was pasted with an epoxy-based adhesive to obtain a polarizing film . On the polarizer side of the resulting polarizing film, sapphire glass (manufactured by Kyocera) having a thickness of 0.5 mm was pasted via an adhesive, and the layer was dried in an oven at 80° C. for 120 minutes to control the water content of the polarizing film. to less than or equal to 1.2wt%. Subsequently, on the 4UYTAC side, a 0.1 mm-thick blue plate glass was pasted, and then the side of the resulting laminate was covered with an ultraviolet curable resin to obtain a polarizing plate having a configuration as shown in FIG. 13 . On the air-contacting surface of sapphire glass and sapphire glass, 5 layers of vacuum-evaporated dielectric substances are used for anti-reflection treatment.

The same light resistance evaluation as in Example 5 was performed, and finally excellent initial evaluation was found, and no deterioration was found even in long-term evaluation. The results are summarized in Table 2 together with Example 5.

(comparative example 3)

On one surface of the polarizing film obtained in the same manner as in Example 5, a sapphire glass (manufactured by Kyocera Corporation) with a thickness of 0.5 mm was pasted via an adhesive, and a thickness of 0.1 mm was pasted on the other side without a drying process. The blue plate glass was used to obtain a laminated body with one side surface not covered with a sealing material (its structure is shown in FIG. 14, a conventional polarizer). This stage has a configuration in which the sides and part of the surface of the laminate not covered with the blue plate glass are in contact with the air. On the air-contacting surface of sapphire glass and sapphire glass, 5 layers of vacuum-evaporated dielectric substances are used for anti-reflection treatment.

The same light fastness evaluation as in Example 5 was performed, and it was found that light leakage due to the deterioration of the polarizer occurred in only 12 hours during the initial evaluation, and in addition, in the case where the ambient temperature was 60° C. and the relative humidity was 90% for 72 hours. , the degradation develops rapidly, and accurate data cannot be obtained. The results are summarized in Table 2.

(comparative example 4)

On one surface of the polarizing film obtained in the same manner as in Example 5, sapphire glass (manufactured by Kyocera) having a thickness of 0.5 mm was pasted via an adhesive, dried in a heating oven at 80° C. for 120 minutes, and then placed on On the other side, a blue plate glass with a thickness of 0.1 mm was pasted to obtain a laminate whose surface was not covered with a sealing material (its structure is shown in FIG. 14 , a conventional polarizer). This stage has a configuration in which the sides and part of the surface of the laminate not covered with the blue plate glass are in contact with the air. On the air-contacting surface of sapphire glass and sapphire glass, 5 layers of vacuum-evaporated dielectric substances are used for anti-reflection treatment.

The same evaluation of light resistance as in Example 5 was performed, and it was found that the initial evaluation results were excellent, but in the case of leaving for 72 hours at an ambient temperature of 60° C. and a relative humidity of 90%, deterioration of the polarizer rapidly progressed. The results are summarized in Table 2.

(Table 2)

Protective film one surface / the other surface Drying conditions Polarizer structure Lightfastness evaluation Early stage (h) long term Example 5 80μm, TAC/80μm, TAC 70℃×180min figure 1 65 ○ 6 80μm, TAC/40μm, Zeonor 80℃×120min image 3 72 ○ 7 40μm, TAC/None 80℃×120min Figure 5 95 ○ comparative example 3 80μm, TAC/80μm, TAC none Figure 6 12 not measurable 4 80μm, TAC/80μm, TAC 80℃×120min Figure 6 60 ×

(Embodiment 8)

On one surface of the polarizing film obtained in the same manner as in Example 5, sapphire glass (manufactured by Kyocera Corporation) having a thickness of 0.5 mm was pasted via an adhesive, dried in a heating oven at 80° C. for 120 minutes, and then The other side is pasted with a 0.1mm thick blue plate glass, and the water content of the polarizing film is controlled to be less than or equal to 1.2wt%. Subsequently, immediately with a syringe having an outer diameter of 0.6 mm, 0.01 ml of sealing material (epoxy-based thermosetting resin, manufactured by CEMEDINE, EP582, viscosity: 280 cP, Water vapor transmission rate: 20 g/m ² ·24 hr), the four sides as the exposed portion of the polarizing film were completely sealed at each position for 15 seconds. Further, the sheet was heated at 120° C. for 2 hours to cure the sealing material, thereby obtaining a polarizing plate of the present invention. The cured substrate (cured sealing material) at this stage had a glass transition temperature of 125°C.

The polarizing plate thus obtained was set in the light path of the blue light channel in the light resistance evaluation device shown in FIG. 26, and it was checked that the time for light leakage due to deterioration was 55 hours.

The light resistance evaluation device used in this program uses a 100W high-pressure mercury lamp manufactured by Phillips as a light source, except that the amount of light irradiated on a polarizing plate, such as a polarizing beam splitter array, is 2.5W per 1cm ² , in the same manner as in Example 5 Evaluate in the same way.

(Example 9)

A polarizing plate of the present invention was obtained by performing the same procedure as in Example 8, except that blue plate glass having a thickness of 1 mm and holes with a diameter of 1 mm at four corners was used as the blue plate glass as shown in FIG. 21 . When the sealing material was injected through the hole portion, the four sides as the exposed portion of the polarizing film were completely sealed within 7 seconds at each position.

The light fastness evaluation results were comparable to those of Example 8.

(Example 10)

On one surface of the polarizing film obtained in the same manner as in Example 5, sapphire glass (manufactured by Kyocera Corporation) having a thickness of 0.5 mm was pasted via an adhesive, dried in a heating oven at 80° C. for 120 minutes, and then The other side is pasted with 0.1mm thick blue plate glass, and the water content of the polarizing film is controlled at 1.2wt% or less. Immediately thereafter, silicone-based ultraviolet curable resin (FX-V550 manufactured by ADEKA Corporation, visco. : 5Pa·s, water vapor transmission rate: 30g/m ² ·24hr) was used as the sealing material, and the four sides as the exposed portion of the polarizing film were completely sealed at each position for 60 seconds. Further, the sheet was irradiated with light of 1 J/cm ² by a high-pressure mercury lamp to cause curing of the sealing material, thereby obtaining a polarizing plate of the present invention. The cured substrate (cured sealing material) at this stage has a glass transition temperature of 200°C.

The same light fastness evaluation as in Example 8 was carried out, and it was detected that the time for light leakage due to deterioration was 60 hours.

(Example 11)

On one surface of the polarizing film obtained in the same manner as in Example 5, sapphire glass (manufactured by Kyocera Corporation) having a thickness of 0.5 mm was pasted via an adhesive, dried in a heating oven at 80° C. for 120 minutes, and then immediately A 0.1mm thick blue plate glass is pasted on the other side, and the water content of the polarizing film is controlled to be less than or equal to 1.2wt%. Immediately thereafter, 0.01 ml of epoxy-based ultraviolet curable resin (KR695A manufactured by ADEKA, viscosity: 0.45 Pa. s, water vapor transmission rate: 50 g/m ² ·24 hr) was used as the sealing material, and the four sides as the exposed portion of the polarizing film were completely sealed at each position for 20 seconds. Further, the sheet was irradiated with light of 3.6 J/cm ² by a high-pressure mercury lamp to cure the sealing material, thereby obtaining a polarizing plate of the present invention.

The same light resistance evaluation as in Example 8 was carried out, and the time until light leakage due to deterioration was detected was 65 hours.

(Example 12)

A polyvinyl alcohol film (VF-PX manufactured by Kuraray Co., Ltd., hereinafter referred to as PVA) was uniaxially stretched, dyed with a red dye, and dried to obtain a polarizer for the blue light channel of a projector, which was used in When the thickness is 28 μm, the degree of polarization to light with a wavelength of 440 nm is 99.9%, and the transmittance is 44.0%. On one surface of the polarizer (PVA), an adhesive containing water-soluble polyamide epoxy resin (product name: Sumirez Resin650) as an active ingredient of carboxyl group-modified polyvinyl alcohol resin (product name: KL318) was used. The mixture was pasted as a protective film with a cellulose acetate base film (KC8UY manufactured by Konica Corporation, hereinafter referred to as 8UYTAC) having a thickness of 80 μm to obtain a polarizing film. On one surface of the final polarizing film, stick a sapphire glass (manufactured by Kyocera Corporation) with a thickness of 0.5 mm via an adhesive, and dry in a heating furnace at 110° C. for 120 minutes while maintaining the structure, thereby the polarizing film The water content is controlled to be less than or equal to 1.2wt%. After drying, stick a 0.1mm blue plate glass on the other surface of the polarizer. Subsequently, an ultraviolet curable resin is applied to cover the cross-section and exposed parts of the polarizer, and after curing, a polarizer having the same structure as the schematic diagram in FIG. 15 is obtained. On the air-contacting surface of sapphire glass and sapphire glass, 5 layers of vacuum-evaporated dielectric substances are used for anti-reflection treatment.

The polarizing plate thus obtained was set in the light path of the blue light channel in the light resistance evaluation device shown in FIG. 26, and it was checked that the time for light leakage due to deterioration was 65 hours. In addition, the obtained samples were left for 72 hours under the conditions of an ambient temperature of 60° C. and a relative humidity of 90%, and then their light resistance was evaluated in the same manner, and no deterioration phenomenon of light leakage was found.

Applying this polarizing plate to the incident side and the exiting side of the liquid crystal element of the optical system of a liquid crystal projector results in a screen with an excellent contrast. In this process, the polarizing plate is arranged such that the surface of the blue plate glass faces the liquid crystal cell on the incident side and the outgoing side.

(Example 13)

On one surface of the polarizer (PVA) obtained in the same manner as in Example 12, a cellulose acetate base film (KC4UY manufactured by Konica Corporation, hereinafter referred to as 4UYTAC) having a thickness of 40 μm was pasted with an epoxy-based adhesive. ) to obtain a polarizing film. On the protective film side of the resulting polarizing film, sapphire glass (manufactured by Kyocera Corporation) having a thickness of 0.5 mm was pasted via an adhesive, and dried in a heating oven at 120° C. for 1 hour to control the water content of the polarizing film. to less than or equal to 1.2wt%. After that, on the polarizer side, a 0.1 mm blue plate glass was pasted. Furthermore, the cross section of the polarizing film was covered with a UV curable resin, thereby obtaining a polarizing plate having the structure shown in FIG. 17 . On the air-contacting surface of sapphire glass and sapphire glass, 5 layers of vacuum-evaporated dielectric substances are used for anti-reflection treatment.

The same lightfastness evaluation as in Example 12 was performed, and finally excellent initial evaluation results were found, and there was no deterioration even in long-term evaluation. The contrast was observed in the same manner as in Example 1, and an excellent screen was obtained. The results are summarized in Table 3 together with Example 12.

(Example 14)

On only one surface of the same polarizer (PVA) as in Example 1, an olefin resin film (registered trademark Zeonor, manufactured by ZEON Corporation, thickness 40 μm) was pasted with an epoxy-based adhesive to obtain a polarizing film. On the protective film side of the obtained polarizing film, a sapphire glass (manufactured by Kyocera Corporation) having a thickness of 0.5 mm was pasted via an adhesive, and dried in a heating oven at 130° C. for 1 hour to control the water content of the polarizing film to less than or equal to 1.2wt%. After that, a 0.1 mm blue plate glass was pasted on the polarizer side. Furthermore, the cross section of the polarizing plate was covered with a UV curable resin, thereby obtaining a polarizing plate having the structure shown in FIG. 17 . On the air-contacting surface of sapphire glass and sapphire glass, 5 layers of vacuum-evaporated dielectric substances are used for anti-reflection treatment.

The same lightfastness evaluation as in Example 12 was performed, and finally excellent initial evaluation results were found, and there was no deterioration even in long-term evaluation. The contrast was observed in the same manner as in Example 12, and an excellent screen was obtained. The results are summarized in Table 3 together with Example 12.

(comparative example 5)

On the polarizer side of the polarizing film obtained in the same manner as in Example 12, a sapphire glass (manufactured by Kyocera Corporation) with a thickness of 0.5 mm was pasted via an adhesive, and without a drying process, on another protective film- A 0.1 mm blue plate glass was pasted on the side to obtain a polarizer having the structure shown in FIG. 19 . In the structure at this stage, the cross section of the polarizer and the part of the surface of the polarizing film not covered by the blue plate glass are in contact with the air. On the air-contacting surface of sapphire glass and sapphire glass, 5 layers of vacuum-evaporated dielectric substances are used for anti-reflection treatment. When this polarizing plate is applied to the incident side and the exiting side of the liquid crystal element of the optical system of the liquid crystal projector, a screen excellent in contrast cannot be obtained. In this process, the polarizers are arranged in such a way that the surface of the blue plate glass faces the liquid crystal cell on the entrance side and the exit side.

The polarizer thus obtained was subjected to the same evaluation of light resistance as in Example 1, and it was found that light leakage due to deterioration of the polarizer occurred in only 12 hours in the initial evaluation stage, and furthermore, at an ambient temperature of 60° C. and a relative humidity of 90% In the case where it was left for 72 hours under certain conditions, the deterioration progressed rapidly, and accurate data could not be obtained. The results are summarized in Table 3.

(comparative example 6)

On the polarizer side of the polarizing film obtained in the same manner as in Example 12, sapphire glass (manufactured by Kyocera Corporation) with a thickness of 0.5 mm was pasted via an adhesive, and heating at 110° C. was performed while maintaining the structure. Oven drying was performed for 120 minutes, thereby controlling the water content of the polarizing film to be less than or equal to 1.2 wt%. After that, a 0.1 mm blue plate glass was pasted on one side of the protective film to obtain a polarizing plate having the structure shown in FIG. 20 . In the structure at this stage, the cross section of the polarizing plate is in contact with air. On the air-contacting surface of sapphire glass and sapphire glass, 5 layers of vacuum-evaporated dielectric substances are used for anti-reflection treatment.

When this polarizing plate is applied to the incident side and the exiting side of the liquid crystal element of the optical system of the liquid crystal projector, a screen excellent in contrast cannot be obtained. In this process, the polarizers are arranged in such a way that the surface of the blue plate glass faces the liquid crystal cell on the entrance side and the exit side.

The polarizer thus obtained was subjected to the same light resistance evaluation as in Example 12, and it was found that light leakage due to deterioration of the polarizer occurred in only 12 hours in the initial evaluation stage, and furthermore, at an ambient temperature of 60° C. and a relative humidity of 90% In the case where it was left for 72 hours under certain conditions, the deterioration progressed rapidly, and accurate data could not be obtained. The results are summarized in Table 3.

(table 3)

structure Drying conditions structure Contrast Initial light resistance (h)/long term protective film Transparent substrate on the polarizer side Example 12 80μm, TAC blue plate glass 110℃×120min Figure 15 ○ 65/○ 13 40μm, TAC blue plate glass 120℃×60min Figure 17 ○ 95/○ 14 40 μm, Zeonor blue plate glass 130℃×60min Figure 17 ○ 72/○ comparative example 5 80μm, TAC Sapphire none Figure 19 × 12/non-splashable amount 6 80μm, TAC Sapphire 110℃×120min Figure 20 × 66/×

When applied to a polarizing plate of a projection type liquid crystal display such as a front projector, a rear projector, etc., the polarizing plate of the present invention can maintain the optical characteristics even in the case of strong irradiation of light from a light source, and can significantly prolong the use of the device life, thus exhibiting excellent practicability.

Claims (30)

CLAIMS 1. A polarizing plate having a transparent substrate on both surfaces of a polarizing film including a polarizer, wherein an exposed portion of the polarizing film not covered by the transparent substrate is covered with a sealing material. 2. The polarizing plate according to claim 1, wherein the water content of the polarizer is less than or equal to 5 wt%. 3. The polarizing plate according to claim 1, wherein the sealing material is an ultraviolet curable adhesive or a heat curable adhesive. 4. The polarizing plate according to claim 3, wherein the sealing material has a glass transition temperature after curing greater than or equal to 80°C. 5. The polarizing plate according to claim 3, wherein the sealing material has a viscosity before curing of 10 Pa·s or less at 25°C. 6. The polarizing plate according to claim 1, wherein the sealing material has a boiling water absorption coefficient after curing of less than or equal to 4 wt%. 7. The polarizing plate according to claim 1, wherein the sealing material has a boiling water absorption coefficient after curing of less than or equal to 2 wt%. 8. The polarizing plate according to claim 1, wherein at least one transparent substrate is made of a material having a thermal conductivity greater than or equal to 5 W/mK. 9. The polarizing plate according to claim 1, wherein a resin layer having a total thickness of more than or Equal to 0.1 μm and less than 10 μm. 10. The polarizing plate according to claim 9, wherein the material of one transparent substrate is quartz crystal or sapphire, and the material of the other substrate is quartz crystal, quartz glass, silicate glass or borosilicate glass. 11. The polarizing plate according to claim 1, wherein the polarizing film is a polarizing film comprising a polarizer and a protective film. 12. The polarizing plate according to claim 11, wherein the polarizing film has a water content less than or equal to 1.6 wt%. 13. The polarizing plate according to claim 11, wherein the protective film has a thickness of 10 to 45 [mu]m. 14. The polarizing plate according to claim 11, wherein the protective film is a film containing triacetyl cellulose or an olefin resin film. 15. The polarizing plate according to claim 11, wherein at least one transparent substrate is made of a material having a thermal conductivity greater than or equal to 5 W/mK. 16. The polarizing plate according to claim 11, wherein a resin layer having a total thickness of more than Or equal to 0.1 μm and less than 10 μm. 17. The polarizing plate according to claim 16, wherein a material of one transparent substrate is quartz crystal or sapphire, and a material of the other substrate is quartz crystal, quartz glass, silicate glass or borosilicate glass. 18. The polarizer according to claim 11, wherein the polarizing film is made up of a polarizer and a protective film, on both surfaces of the polarizing film, a transparent substrate is pasted, and the transparent substrate pasted on the polarizer is A transparent substrate made of a material that is not optically anisotropic. 19. The polarizing plate according to claim 18, wherein the transparent substrate having non-optical anisotropy is made of silicate glass or borosilicate glass. 20. The polarizing plate according to claim 1, wherein the polarizing plate has a laminated portion having a thickness between the polarizer and at least one transparent substrate of greater than or equal to 1 μm and less than or equal to 30 μm, and the laminated portion is formed by heat Cured resin or ultraviolet cured resin formed of two or more resin layers, and the laminated part includes an adhesive layer. 21. The polarizing plate according to claim 20, wherein the content of volatile components of the resin layer formed in the polarizing plate is less than or equal to 2 wt % before curing. 22. The polarizing plate according to claim 20, wherein the resin layer formed in the polarizing plate has a viscosity at 25[deg.] C. before curing of 0.01 Pa·s or more and 20 Pa·s or less. 23. The polarizing plate according to claim 20, wherein when the resin layer formed in the polarizing plate has a thickness of 25 μm after being cured, light transmittance in a wavelength range of 400 nm to 700 nm is greater than or equal to 90%. 24. A method of manufacturing a polarizing plate having a transparent substrate on both surfaces of a polarizing film comprising a polarizer, and wherein an exposed portion of the polarizing film not covered with the transparent substrate is covered with a sealing material, wherein The transparent substrate is bonded to both surfaces of the polarizing film with resin, the polarizing film is dried, and then the exposed portion of the polarizing film not covered by the transparent substrate is covered with a sealing material. 25. The method for manufacturing a polarizing plate according to claim 24, wherein in the process of bonding the transparent substrate to the polarizing film with resin, at least one of the following steps is carried out under reduced pressure: The process of forming the resin layer before the resin used as the adhesive layer, and the process of setting the bonding object. 26. The method of manufacturing a polarizing plate according to claim 24, wherein the method comprises a step of drying the polarizing film at a temperature of 110° C. or less before bonding the second transparent substrate to the polarizing film. 27. The method for manufacturing a polarizing plate according to claim 24, wherein at least one of the transparent substrates has a recessed portion and/or a hole portion for injecting a sealant, and the method comprises injecting the sealant through the recessed portion and/or the hole portion process. 28. A projection type liquid crystal display having the polarizer according to claim 1. 29. The polarizing plate according to claim 1, wherein when the resin covering the exposed portion of the polarizer has a cured thickness of 100 μm, the water vapor transmission rate at an ambient temperature of 40° C. and a relative humidity of 90% is less than Or equal to 60g/m ² ·24hr. 30. The polarizing plate according to claim 1, wherein when the resin covering the exposed portion of the polarizer has a cured thickness of 100 μm, the water vapor transmission rate at an ambient temperature of 40° C. and a relative humidity of 90% is less than Or equal to 25g/m ² ·24hr.

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