JP2020140212A - Circularly polarizing plate and display device - Google Patents

Abstract

To provide a thin and wide-band circularly polarizing plate and a display device including the circularly polarizing plate.SOLUTION: A circularly polarizing plate includes a substrate, a retardation layer, and a polarizing layer. The retardation layer has birefringence Δn(λ) for light at a wavelength of λ nm, satisfying expression (1):Δn(450)/Δn(550)≤1.00 and expression (2):1.00≤Δn(650)/Δn(550). The retardation layer and the polarizing layer are both coating layers, in which the total thickness of the retardation layer and the polarizing layer is 10 μm or less. The polarizing layer contains a dichroic dye.SELECTED DRAWING: Figure 1

Description

The present invention relates to a circularly polarizing plate and a display device.

A liquid crystal display device including a polarizing film made of polyvinyl alcohol dyed with iodine and a broadband circular polarizing plate in which a 1/2 wave plate and a 1/4 wave plate are laminated is known. In such a broadband circular polarizing plate, the angle formed by the slow axis of the 1/2 wave plate and the absorption axis of the polarizing film and the angle formed by the slow axis of the 1/4 wave plate and the absorption axis of the polarizing film are 15 respectively. It is difficult to produce the circularly polarizing plate by roll-to-roll bonding because it is necessary to stack them with a difference of ° or 75 °. On the other hand, there is a strong demand for thinner display devices, and therefore, thinner circular polarizing plates are also required.

Patent Document 1 describes a circular polarizing plate having a thickness of 130 to 370 μm, in which a polarizing element obtained by applying a reverse wavelength dispersive film and a dichroic dye is laminated on a retardation layer. ..
Patent Document 2 describes a circular polarizing plate having a thickness of 36 to 205 μm, in which a polarizer containing a thermotropic liquid crystal or lyotropic liquid crystal substance is laminated on a retardation layer.

Japanese Unexamined Patent Publication No. 2006-337892 Japanese Unexamined Patent Publication No. 2009-251288

However, since the circularly polarizing plate described in Patent Document 1 is made by laminating two films via an adhesive or an adhesive, it is sufficiently satisfactory from the viewpoint of simplicity of the manufacturing process and the thickness of the circularly polarizing plate. I didn't get it. The circularly polarizing plate described in Patent Document 2 has insufficient performance as a wideband circularly polarizing plate because its retardation layer exhibits positive wavelength dispersibility.

The present invention includes the following inventions.
[1] It has a base material, a retardation layer, and a polarizing layer, and the dichroism Δn (λ) of the retardation layer with respect to light having a wavelength of λ nm satisfies the equations (1) and (2), and the retardation A circular polarizing plate characterized in that both the layer and the polarizing layer are coating layers, the total thickness of the retardation layer and the polarizing layer is 10 μm or less, and the polarizing layer contains a dichroic dye.
Δn (450) / Δn (550) ≦ 1.00 (1)
1.00 ≦ Δn (650) / Δn (550) (2)
[2] The circularly polarizing plate according to [1], which is formed by polymerizing a polymerizable liquid crystal having one or more retardation layers.
[3] The circular polarizing plate according to [1] or [2], wherein the polarizing layer is formed by polymerizing one or more polymerizable liquid crystals.
[4] The circularly polarizing plate according to [2] or [3], wherein a polymerizable liquid crystal is polymerized by light irradiation.
[5] The circular polarizing plate according to any one of [1] to [4], wherein the polarizing layer is a polarizing layer from which a Bragg peak can be obtained in X-ray diffraction measurement.
[6] The circular polarizing plate according to any one of [1] to [5], wherein the retardation layer and the polarizing layer each have a thickness of 5 μm or less.
[7] The circular polarizing plate according to any one of [1] to [6], wherein the retardation layer, the polarizing layer, or both are formed on the alignment film.
[8] The circularly polarizing plate according to [7], wherein the alignment film is an alignment film in which an orientation regulating force is generated by light irradiation.
[9] The circularly polarizing plate according to [7] or [8], wherein the alignment film has a thickness of 500 nm or less.
[10] A retardation layer is formed on the base material with or without an alignment film, and a polarizing layer is formed on the retardation layer with or without an alignment film [1]. The circular polarizing plate according to any one of [9].
[11] A polarizing layer is formed on the substrate with or without an alignment film, and a retardation layer is formed on the polarizing layer with or without an alignment film [1] to The circularly polarizing plate according to any one of [9].
[12] The circular polarizing plate according to [10] or [11], which has a protective layer between a polarizing layer and a retardation layer.
[13] A polarizing layer is formed on one surface of the base material with or without an alignment film, and a retardation layer is formed on the other surface of the base material with or without an alignment film. The circular polarizing plate according to any one of [1] to [9].
[14] The circular polarizing plate according to any one of [1] to [13], further having an adhesive layer on the surface of the retardation layer or the polarizing layer.
[15] The circular polarizing plate according to [14], which has a base material, a first alignment film, a polarizing layer, a second alignment film, a retardation layer, and an adhesive layer in this order.
[16] The peel strength between the base material and the first alignment film (F1) is the peel strength between the first alignment film and the polarizing layer (F2), and the peel strength between the second alignment film and the retardation layer (F1). The circularly polarizing plate according to F3) and [15], which is lower than the peel strength (F4) between the retardation layer and the pressure-sensitive adhesive layer.
[17] A display device including the circularly polarizing plate according to any one of [1] to [16] and a display element.
[18] The circularly polarizing film from which the base material has been removed from the circularly polarizing plate according to any one of [14] to [16] is bonded to the display surface of the display element via the pressure-sensitive adhesive layer of the circularly polarizing film. Display device with circular polarizing film.
[19] The display device according to [18], wherein the thickness of the circularly polarizing film is 5 μm or more and 15 μm or less.
[20] The display device according to any one of [17] to [19], wherein the display element is a liquid crystal cell, an organic electroluminescence element, or a touch panel.
[21] The circularly polarizing plate according to any one of [14] to [16] is attached to the display surface of the display element via the adhesive layer of the circularly polarizing plate, and the base material is removed from the circularly polarizing plate. A method for manufacturing a display device with a circular polarizing film to be removed.

According to the present invention, it is possible to provide a thin and wide band circularly polarizing plate and a display device including the circularly polarizing plate.

It is sectional drawing of the circular polarizing plate of this invention. It is a schematic diagram of the liquid crystal display device including the circular polarizing plate of this invention. It is a schematic diagram of the organic EL display device including the circular polarizing plate of this invention.

The substrate is usually a transparent substrate. When the base material of the circularly polarizing plate of the present invention (hereinafter, sometimes referred to as the present circularly polarizing plate) is not installed on the display surface of the display element, for example, a circularly polarizing film obtained by removing the base material from the present circularly polarizing plate. When installed on the display surface of the display element, the base material does not have to be transparent. The transparent base material means a base material having transparency capable of transmitting light, particularly visible light, and the transparency means a characteristic that the transmittance for light having a wavelength of 380 to 780 nm is 80% or more. Say. Specific examples of the transparent base material include a translucent resin base material. Resins constituting the translucent resin base material include polyolefins such as polyethylene and polypropylene; cyclic olefin resins such as norbornene-based polymers; polyvinyl alcohol; polyethylene terephthalate; polymethacrylic acid ester; polyacrylic acid ester; triacetylcellulose, Cellulose esters such as diacetyl cellulose and cellulose acetate propionate; polyethylene naphthalate; polycarbonate; polysulfone; polyethersulfone; polyether ketone; polyphenylene sulfide and polyphenylene oxide. From the viewpoint of availability and transparency, polyethylene terephthalate, polymethacrylic acid ester, cellulosic ester, cyclic olefin resin or polycarbonate are preferable.

Cellulose esters are those in which some or all of the hydroxyl groups contained in cellulose are esterified and are easily available on the market. Cellulose ester substrates are also readily available on the market. Examples of commercially available cellulose ester base materials include "Fujitack Film" (Fuji Photo Film Co., Ltd.); "KC8UX2M", "KC8UY" and "KC4UY" (Konica Minolta Opto Co., Ltd.).

Cyclic olefin resins are readily available on the market. Commercially available cyclic olefin resins include "Topas" [Ticona (Germany)], "Arton" [JSR Corporation], "ZEONOR" [Zeon Corporation], and "ZEONEX". [Zeon Corporation] and "Apel" [manufactured by Mitsui Chemicals, Inc.] can be mentioned. Such a cyclic olefin resin can be used as a base material by forming a film by a known means such as a solvent casting method or a melt extrusion method. Further, a commercially available cyclic olefin resin base material can also be used. Commercially available cyclic olefin resin base materials include "Sushina" [Sekisui Chemical Co., Ltd.], "SCA40" [Sekisui Chemical Co., Ltd.], "Zeonoa Film" [Optes Co., Ltd.] and "Arton Film". [JSR Corporation] can be mentioned.

When the cyclic olefin resin is a copolymer of a cyclic olefin and an aromatic compound having a chain olefin or a vinyl group, the content ratio of the structural unit derived from the cyclic olefin is the total structural unit of the copolymer. On the other hand, it is usually in the range of 50 mol% or less, preferably 15 to 50 mol%. Examples of the chain olefin include ethylene and propylene, and examples of the aromatic compound having a vinyl group include styrene, α-methylstyrene and alkyl-substituted styrene. When the cyclic olefin resin is a ternary copolymer of a cyclic olefin, a chain olefin, and an aromatic compound having a vinyl group, the content ratio of the structural unit derived from the chain olefin is the content of the copolymer. It is usually 5 to 80 mol% with respect to the total structural units, and the content ratio of the structural units derived from the aromatic compound having a vinyl group is usually 5 to 80 mol% with respect to all the structural units of the copolymer. Is. Such a ternary copolymer has an advantage that the amount of expensive cyclic olefin used can be relatively reduced in the production thereof.

The characteristics required for the base material differ depending on the configuration of the circularly polarizing plate, but usually, a base material having as little retardation as possible is preferable. Examples of the base material having the smallest possible phase difference include cellulose ester films having no phase difference such as Zero Tuck (Konica Minolta Opto Co., Ltd.) and Z Tuck (Fuji Film Co., Ltd.). Further, an unstretched cyclic olefin resin base material is also preferable.

In the case of a circularly polarizing plate in which a polarizing layer is formed on a substrate with or without an alignment film, and a retardation layer is formed on the polarizing layer with or without an alignment film. A hard coat treatment, an antireflection treatment, an antistatic treatment, or the like may be applied to the surface of the base material on which the layer is not formed. Further, the hard coat layer may contain an additive such as an ultraviolet absorber as long as it does not affect the performance.

If the thickness of the base material is too thin, the strength tends to decrease and the workability tends to be poor. Therefore, the thickness is usually 5 to 300 μm, preferably 20 to 200 μm.

The retardation layer is a coating layer in which the double refractive index Δn (λ) with respect to light having a wavelength of λ nm satisfies the formulas (1) and (2). The coating layer is a layer formed by coating.
Δn (450) / Δn (550) ≦ 1.00 (1)
1.00 ≦ Δn (650) / Δn (550) (2)

The double refractive index Δn (λ) is obtained by measuring retardation and dividing by the thickness of the retardation layer. A specific measurement method is shown in the examples. At this time, by measuring a film formed on a substrate such as a glass substrate having no retardation, a substantial retardation layer can be obtained. The characteristics can be measured.

The retardation layer is preferably formed by polymerizing one or more polymerizable liquid crystals (hereinafter, may be referred to as polymerizable liquid crystal (A)).

The polymerizable liquid crystal is a compound having a polymerizable group and having liquid crystallinity. The polymerizable group means a group involved in the polymerization reaction, and is preferably a photopolymerizable group. Here, the photopolymerizable group refers to a group that can participate in the polymerization reaction by an active radical, an acid, or the like generated from a photopolymerization initiator described later. Examples of the polymerizable group include a vinyl group, a vinyloxy group, a 1-chlorovinyl group, an isopropenyl group, a 4-vinylphenyl group, an acryloyloxy group, a methacryloyloxy group, an oxylanyl group, an oxetanyl group and the like. Of these, an acryloyloxy group, a methacryloyloxy group, a vinyloxy group, an oxylanyl group and an oxetanyl group are preferable, and an acryloyloxy group is more preferable. The liquid crystal property may be a thermotropic liquid crystal or a riotropic liquid crystal, and when the thermotropic liquid crystal is classified according to the order, it may be a nematic liquid crystal or a smectic liquid crystal.

Among them, a thermotropic nematic liquid crystal is preferable from the viewpoint of ease of film formation, and the following formula (A) is given from the viewpoint of imparting retardation represented by the formulas (1) and (2). The compound represented by (hereinafter, may be referred to as compound (A)) is preferable. The polymerizable liquid crystal may be used alone or in combination.

［式（Ａ）中、
Ｘ^１は、酸素原子、硫黄原子またはＮＲ^１−を表わす。Ｒ^１は、水素原子または炭素数１〜４のアルキル基を表わす。
Ｙ^１は、置換基を有していてもよい炭素数６〜１２の１価の芳香族炭化水素基または置換基を有していてもよい炭素数３〜１２の１価の芳香族複素環式基を表わす。
Ｑ^３およびＱ^４は、それぞれ独立に、水素原子、置換基を有していてもよい炭素数１〜２０の１価の脂肪族炭化水素基、炭素数３〜２０の１価の脂環式炭化水素基、置換基を有していてもよい炭素数６〜２０の１価の芳香族炭化水素基、ハロゲン原子、シアノ基、ニトロ基、−ＮＲ^２Ｒ^３または−ＳＲ^２を表わすか、または、Ｑ^３とＱ^４とが互いに結合して、これらが結合する炭素原子とともに芳香環または芳香族複素環を形成する。Ｒ^２およびＲ^３は、それぞれ独立に、水素原子または炭素数１〜６のアルキル基を表わす。
Ｄ^１およびＤ^２は、それぞれ独立に、単結合、−Ｃ（＝Ｏ）−Ｏ−、−Ｃ（＝Ｓ）−Ｏ−、−ＣＲ^４Ｒ^５−、−ＣＲ^４Ｒ^５−ＣＲ^６Ｒ^７−、−Ｏ−ＣＲ^４Ｒ^５−、−ＣＲ^４Ｒ^５−Ｏ−ＣＲ^６Ｒ^７−、−ＣＯ−Ｏ−ＣＲ^４Ｒ^５−、−Ｏ−ＣＯ−ＣＲ^４Ｒ^５−、−ＣＲ^４Ｒ^５−Ｏ−ＣＯ−ＣＲ^６Ｒ^７−、−ＣＲ^４Ｒ^５−ＣＯ−Ｏ−ＣＲ^６Ｒ^７−またはＮＲ^４−ＣＲ^５Ｒ^６−またはＣＯ−ＮＲ^４−を表わす。
Ｒ^４、Ｒ^５、Ｒ^６およびＲ^７は、それぞれ独立に、水素原子、フッ素原子または炭素数１〜４のアルキル基を表わす。
Ｇ^１およびＧ^２は、それぞれ独立に、炭素数５〜８の２価の脂環式炭化水素基を表わし、該脂環式炭化水素基を構成するメチレン基は、酸素原子、硫黄原子またはＮＨ−に置き換っていてもよく、該脂環式炭化水素基を構成するメチン基は、第三級窒素原子に置き換っていてもよい。
Ｌ^１およびＬ^２は、それぞれ独立に、１価の有機基を表わし、Ｌ^１およびＬ^２のうちの少なくとも一つは、重合性基を有する。］

[In formula (A),
X ¹ represents an oxygen atom, a sulfur atom or NR ¹ −. R ¹ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.
Y ¹ is a monovalent aromatic hydrocarbon group having 6 to 12 carbon atoms which may have a substituent or a monovalent aromatic heterocycle having 3 to 12 carbon atoms which may have a substituent. Represents an expression group.
Q ³ and Q ⁴ are, each independently, a hydrogen atom, a monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms that may have a substituent, a monovalent alicyclic having 3 to 20 carbon atoms Represents a hydrocarbon group, a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms which may have a substituent, a halogen atom, a cyano group, a nitro group, -NR ² R ³ or -SR ² . Alternatively, Q ³ and Q ⁴ are bonded to each other to form an aromatic ring or an aromatic heterocycle together with the carbon atoms to which they are bonded. R ² and R ³ independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
D ¹ and ^{D 2} are each independently a single bond, -C (= O) -O - , - C (= S) -O -, - CR 4 R 5 -, - CR 4 R 5 -CR 6 R ^{7 -, - O-CR 4} R 5 -, - CR 4 R 5 -O-CR 6 R 7 -, - CO-O-CR 4 R 5 -, - O-CO-CR 4 R 5 -, - CR ^{4 R 5 -O-CO-CR} 6 R 7 -, - CR 4 R 5 -CO-O-CR 6 R 7 - or ^NR 4 ^-CR 5 ^{R 6} - or CO-NR ⁴ - represents a.
R ⁴ , R ⁵ , R ⁶ and R ⁷ each independently represent a hydrogen atom, a fluorine atom or an alkyl group having 1 to 4 carbon atoms.
G ¹ and G ² each independently represent a divalent alicyclic hydrocarbon group having 5 to 8 carbon atoms, and the methylene group constituting the alicyclic hydrocarbon group is an oxygen atom, a sulfur atom or NH. It may be replaced with −, and the methine group constituting the alicyclic hydrocarbon group may be replaced with a tertiary nitrogen atom.
L ¹ and L ² each independently represent a monovalent organic group, and at least one of L ¹ and L ² has a polymerizable group. ]

L ¹ in the compound (A) is preferably a group represented by the formula (A1), and L ² is preferably a group represented by the formula (A2).
P ¹ −F ¹ − (B ¹ − A ¹ ) _k − E ¹ − (A1)
P ^2- F ^2- (B ^2- A ² ) _l- E ^2- (A2)
[In equations (A1) and (A2),
B ¹ , B ² , E ¹ and E ² are independently -CR ⁴ R ^5- , -CH _2- CH _2-, -O-, -S-, -CO-O-, -O-CO. Represents -O-, -CS-O-, -O-CS-O-, -CO-NR ^1- , -O-CH _2- , -S-CH _2- or single bond.
A ¹ and A ² independently represent a divalent alicyclic hydrocarbon group having 5 to 8 carbon atoms or a divalent aromatic hydrocarbon group having 6 to 18 carbon atoms, and the alicyclic hydrocarbons. The methylene group constituting the group may be replaced with an oxygen atom, a sulfur atom or NH-, and the methine group constituting the alicyclic hydrocarbon group is replaced with a tertiary nitrogen atom. May be good.
k and l each independently represent an integer of 0 to 3.
F ¹ and F ² represent divalent aliphatic hydrocarbon groups having 1 to 12 carbon atoms.
P ¹ represents a polymerizable group.
P ² represents a hydrogen atom or a polymerizable group.
R ⁴ and R ⁵ each independently represent a hydrogen atom, a fluorine atom, or an alkyl group having 1 to 4 carbon atoms. ]

Preferred compounds (A) include the compounds described in JP-A-2011-207765.

Specific examples of the polymerizable liquid crystal include "3.8.6 network (completely crosslinked type)" and "6." of the Liquid Crystal Handbook (edited by the Liquid Crystal Handbook Editorial Committee, published by Maruzen Co., Ltd. on October 30, 2000). Among the compounds described in "5.1 Liquid Crystal Material b. Polymerizable Nematic Liquid Crystal Material", a compound having a polymerizable group can be mentioned.

As the retardation layer, a composition containing one or more polymerizable liquid crystals (A) is usually applied onto a base material, an alignment film or a polarizing layer, and the polymerizable liquid crystal (A) in the obtained coating film is obtained. Is formed by polymerizing.

The alignment film in the present invention has an orientation-regulating force that aligns the polymerizable liquid crystal in a desired direction.
The alignment film preferably has solvent resistance that does not dissolve when a composition containing a polymerizable liquid crystal is applied, and has heat resistance in heat treatment for removing the solvent and aligning the polymerizable liquid crystal. Examples of such an alignment film include an alignment film containing an alignment polymer and a photoalignment film.

Examples of the oriented polymer include polyamides and gelatins having an amide bond in the molecule, polyimide having an imide bond in the molecule and its hydrolyzate polyamic acid, polyvinyl alcohol, alkyl-modified polyvinyl alcohol, polyacrylamide, and polyoxazole. Examples include polyethyleneimine, polystyrene, polyvinylpyrrolidone, polyacrylic acid and polyacrylic acid esters. Of these, polyvinyl alcohol is preferable. Two or more kinds of oriented polymers may be used in combination.

The alignment film containing the orientation polymer is usually obtained by applying a composition in which the orientation polymer is dissolved in a solvent (hereinafter, may be referred to as an orientation polymer composition) to a substrate to remove the solvent or orient the alignment film. It is obtained by applying a sex polymer composition to a substrate, removing a solvent, and rubbing (rubbing method).

Examples of the solvent include water, methanol, ethanol, ethylene glycol, isopropyl alcohol, propylene glycol, methyl cellosolve, butyl cellosolve, propylene glycol monomethyl ether and other alcohol solvents, ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, γ-butyrolactone, and the like. Ester solvents such as propylene glycol methyl ether acetate and ethyl lactate, ketone solvents such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, methyl amyl ketone and methyl isobutyl ketone, aliphatic hydrocarbon solvents such as pentane, hexane and heptane, toluene, Examples thereof include aromatic hydrocarbon solvents such as xylene, nitrile solvents such as acetonitrile, ether solvents such as tetrahydrofuran and dimethoxyethane, and chlorinated hydrocarbon solvents such as chloroform and chlorobenzene. These solvents may be used alone or in combination of two or more.

The concentration of the oriented polymer in the oriented polymer composition may be within the range in which the oriented polymer material can be completely dissolved in the solvent, but is preferably 0.1 to 20% in terms of solid content with respect to the solution, and is 0. .1 to 10% is more preferable.

As the orientation polymer composition, a commercially available alignment film material may be used as it is. Examples of commercially available alignment film materials include Sunever (registered trademark, manufactured by Nissan Chemical Industries, Ltd.) and Optomer (registered trademark, manufactured by JSR Corporation).

Examples of the method for applying the oriented polymer composition to the substrate include a spin coating method, an extrusion method, a gravure coating method, a die coating method, a bar coating method, an applicator method and other coating methods, and a flexography method and other printing methods. Known methods such as. When the circularly polarizing plate is manufactured by a rolling-to-roll type continuous manufacturing method described later, a printing method such as a gravure coating method, a die coating method, or a flexographic method is usually adopted as the coating method.

Examples of the method for removing the solvent contained in the oriented polymer composition include a natural drying method, a ventilation drying method, a heat drying method and a vacuum drying method.

Rubbing can be performed as needed in order to impart an orientation regulating force to the alignment film (rubbing method).

As a method of imparting orientation-regulating force by the rubbing method, a rubbing cloth is wrapped around a rotating rubbing roll, and an orientation polymer composition is applied to the substrate and annealed to form the surface of the substrate. Examples thereof include a method of contacting a film of an oriented polymer.

The photoalignment film is usually formed by applying a composition containing a polymer or monomer having a photoreactive group and a solvent (hereinafter, may be referred to as a “composition for forming a photoalignment film”) to a substrate and polarizing the film. Preferably, it is obtained by irradiating with polarized UV). The photoalignment film is more preferable in that the direction of the orientation regulating force can be arbitrarily controlled by selecting the polarization direction of the polarized light to be irradiated.

A photoreactive group is a group that produces a liquid crystal orientation ability when irradiated with light. Specific examples thereof include groups involved in photoreactions that are the origin of liquid crystal orientation ability such as molecular orientation induction or isomerization reaction, dimerization reaction, photocrosslinking reaction or photodecomposition reaction generated by light irradiation. Of these, groups involved in the dimerization reaction or photocrosslinking reaction are preferable because they are excellent in orientation. As the photoreactive group, an unsaturated bond, particularly a group having a double bond is preferable, and a carbon-carbon double bond (C = C bond), a carbon-nitrogen double bond (C = N bond), and a nitrogen-nitrogen bond are used. A group having at least one selected from the group consisting of a double bond (N = N bond) and a carbon-oxygen double bond (C = O bond) is particularly preferable.

Examples of the photoreactive group having a C = C bond include a vinyl group, a polyene group, a stilbene group, a still bazol group, a still bazolium group, a chalcone group and a cinnamoyl group. Examples of the photoreactive group having a C = N bond include a group having a structure such as an aromatic Schiff base and an aromatic hydrazone. Examples of the photoreactive group having an N = N bond include an azobenzene group, an azonaphthalene group, an aromatic heterocyclic azo group, a bisazo group, a formazan group, and a group having an azoxybenzene structure. Examples of the photoreactive group having a C = O bond include a benzophenone group, a coumarin group, an anthraquinone group and a maleimide group. These groups may have substituents such as an alkyl group, an alkoxy group, an allyl group, an allyloxy group, a cyano group, an alkoxycarbonyl group, a hydroxyl group, a sulfonic acid group and an alkyl halide group.

Among them, a photoreactive group involved in a photodimerization reaction is preferable, a polarization irradiation amount required for photoalignment is relatively small, and a photoalignment film having excellent thermal stability and temporal stability can be easily obtained. Cinnamoyle groups and chalcone groups are preferred. As the polymer having a photoreactive group, a polymer having a cinnamoyl group such that the terminal portion of the side chain of the polymer has a cinnamon acid structure is particularly preferable.

By applying the composition for forming a photoalignment film onto a base material, a photoalignment-inducing layer can be formed on the base material. Examples of the solvent contained in the composition include the same solvents as those contained in the above-mentioned oriented polymer composition, which can be appropriately selected depending on the solubility of the polymer or monomer having a photoreactive group. ..

The content of the polymer or monomer having a photoreactive group in the composition for forming a photoalignment film can be appropriately adjusted depending on the type of the polymer or monomer and the thickness of the target photoalignment film, but is at least 0.2% by mass. It is preferable that the amount is in the range of 0.3 to 10% by mass. The composition for forming a photoalignment film may contain a polymer material such as polyvinyl alcohol or polyimide or a photosensitizer as long as the characteristics of the photoalignment film are not significantly impaired.

Examples of the method of applying the composition for forming a photoalignment film to the base material include the same method as the method of applying the orientation polymer composition to the base material. Examples of the method for removing the solvent from the applied composition for forming a photoalignment film include the same method as the method for removing the solvent from the oriented polymer composition.

In order to irradiate polarized light, even in the form of directly irradiating polarized UV from the composition for forming a photoalignment film coated on the substrate, the polarized light is transmitted from the base material side. It may be in the form of being irradiated. Further, it is particularly preferable that the polarized light is substantially parallel light. The wavelength of the polarized light to be irradiated is preferably in the wavelength range in which the photoreactive group of the polymer or monomer having a photoreactive group can absorb light energy. Specifically, UV (ultraviolet rays) having a wavelength in the range of 250 to 400 nm is particularly preferable. Examples of the light source used for the polarized light irradiation include xenon lamps, high-pressure mercury lamps, ultra-high pressure mercury lamps, metal halide lamps, ultraviolet light lasers such as KrF and ArF, and high-pressure mercury lamps, ultra-high pressure mercury lamps, and metal halides. Lamps are more preferred. These lamps are preferable because they have a high emission intensity of ultraviolet rays having a wavelength of 313 nm. Polarized UV can be irradiated by irradiating the light from the light source through an appropriate polarizer. As such a polarizing element, a polarizing filter, a polarizing prism such as a Gran Thomson or a Granter, or a wire grid type polarizing element can be used.

If masking is performed during rubbing or polarized light irradiation, it is possible to form a plurality of regions (patterns) having different directions of liquid crystal orientation.

The thickness of the alignment film (alignment film containing the alignment polymer and the photoalignment film) is usually in the range of 10 nm to 10,000 nm, preferably in the range of 10 nm to 1000 nm, more preferably 500 nm or less, and further preferably. It is in the range of 10 nm to 100 nm.

The composition containing one or more polymerizable liquid crystals (A) used for forming the retardation layer (hereinafter, may be referred to as composition A) usually contains a solvent, and the solvent has the above-mentioned orientation. Examples thereof include the same solvents as those contained in the polymer composition, which can be appropriately selected depending on the solubility of the polymerizable liquid crystal (A).

The composition A is usually applied by a known method such as a spin coating method, an extrusion method, a gravure coating method, a die coating method, a bar coating method, an applicator method, or a printing method such as a flexographic method. Is done by. After coating, a dry film is usually formed by removing the solvent under the condition that the polymerizable liquid crystal (A) contained in the obtained coating film does not polymerize. Examples of the drying method include a natural drying method, a ventilation drying method, a heat drying method and a vacuum drying method.

The polymerization of the polymerizable liquid crystal (A) can be carried out by a known method of polymerizing a compound having a polymerizable functional group. Specific examples thereof include thermal polymerization and photopolymerization, and photopolymerization is preferable from the viewpoint of easiness of polymerization. When the polymerizable liquid crystal (A) is polymerized by photopolymerization, the polymerizable liquid crystal (A) in the dry film obtained by applying and drying the composition A containing the photopolymerization initiator is brought into a liquid crystal phase state, and then the polymerizable liquid crystal (A) is brought into a liquid crystal phase state. It is preferable to photopolymerize while maintaining the liquid crystal state.

Photopolymerization is usually carried out by irradiating the dry film with light. The light to be irradiated depends on the type of the photopolymerization initiator contained in the dry film, the type of the polymerizable liquid crystal (A) (particularly, the type of the photopolymerizable group contained in the polymerizable liquid crystal (A)) and the amount thereof. Light and active electron beam selected as appropriate and specifically selected from the group consisting of visible light, ultraviolet light and laser light can be mentioned. Among them, ultraviolet light is preferable because it is easy to control the progress of the polymerization reaction and it is possible to use a photopolymerization apparatus widely used in the art, so that photopolymerization can be performed by ultraviolet light. It is preferable to select the type of the polymerizable liquid crystal (A) or the photopolymerization initiator. Further, at the time of polymerization, the polymerization temperature can be controlled by irradiating light while cooling the dry film by an appropriate cooling means. By adopting such a cooling means, if the polymerizable liquid crystal (A) is polymerized at a lower temperature, a retardation layer can be appropriately formed even if a base material having a relatively low heat resistance is used. At the time of photopolymerization, a patterned retardation layer can also be obtained by masking or developing.

The total thickness of the retardation layer and the polarizing layer in this circular polarizing plate is 10 μm or less. The thickness of the retardation layer is preferably 0.5 μm or more and 9.5 μm or less, and more preferably 1 μm or more and 5 μm or less. The thickness of the polarizing layer is preferably 0.5 μm or more and 9.5 μm or less, and more preferably 1 μm or more and 5 μm or less. The thickness of the retardation layer and the polarizing layer can usually be determined by measurement with an interference film thickness meter, a laser microscope or a stylus film thickness meter.

The polarizing layer contains a dichroic dye. The "dichroic dye" means a dye having a property that the absorbance in the major axis direction and the absorbance in the minor axis direction of the molecule are different. As long as it has such properties, the dichroic dye is not limited and may be a dye or a pigment. Two or more kinds of dyes may be used in combination, two or more kinds of pigments may be used in combination, or a dye and a pigment may be used in combination.

The dichromatic dye preferably has a maximum absorption wavelength (λMAX) in the range of 300 to 700 nm. Examples of such a dichroic dye include an acridine dye, an oxazine dye, a cyanine dye, a naphthalene dye, an azo dye and an anthraquinone dye, and among them, the azo dye is preferable. Examples of the azo dye include monoazo dye, bisazo dye, trisazo dye, tetrakisazo dye and stilbene azo dye, and bisazo dye and trisazo dye are preferable.

Examples of the azo dye include a compound represented by the formula (1) (hereinafter, sometimes referred to as “compound (1)”).
A ¹ (-N = N-A ² ) _p -N = N-A ³ (1)
[In equation (1),
A ¹ and A ³ are independent of each other, a phenyl group which may have a substituent, a naphthyl group which may have a substituent, or a monovalent heterocyclic group which may have a substituent. Represents. A ² is a p-phenylene group which may have a substituent, a naphthalene-1,4-diyl group which may have a substituent, or a divalent heterocycle which may have a substituent. Represents a group. p represents an integer of 1 to 4. When p is an integer of 2 or more, the plurality of A ^2s may be the same or different from each other. ]

Examples of the monovalent heterocyclic group include a group obtained by removing one hydrogen atom from a heterocyclic compound such as quinoline, thiazole, benzothiazole, thienothiazole, imidazole, benzimidazole, oxazole, and benzoxazole. Examples of the divalent heterocyclic group include a group obtained by removing two hydrogen atoms from the heterocyclic compound.

As a substituent optionally contained in a phenyl group, a naphthyl group and a monovalent heterocyclic group in A ¹ and A ^3, and a p-phenylene group, a naphthalene-1,4-diyl group and a divalent heterocyclic group in A ² . Is an alkyl group having 1 to 4 carbon atoms; an alkoxy group having 1 to 4 carbon atoms such as a methoxy group, an ethoxy group and a butoxy group; an alkyl fluoride group having 1 to 4 carbon atoms such as a trifluoromethyl group; a cyano group; Nitro group; Halogen atom; Substituent or unsubstituted amino group such as amino group, diethylamino group, pyrrolidino group (Substituent amino group is an amino group having one or two alkyl groups having 1 to 6 carbon atoms, or two It means an amino group in which substituted alkyl groups are bonded to each other to form an alcandiyl group having 2 to 8 carbon atoms. The unsubstituted amino group is -NH ₂ ).

［式（１−１）〜（１−６）中、
Ｂ^１〜Ｂ^２０は、互いに独立に、水素原子、炭素数１〜６のアルキル基、炭素数１〜４のアルコキシ基、シアノ基、ニトロ基、置換または無置換のアミノ基（置換アミノ基および無置換アミノ基の定義は前記のとおり）、塩素原子またはトリフルオロメチル基を表わす。
ｎ１〜ｎ４は、互いに独立に０〜３の整数を表わす。
ｎ１が２以上である場合、複数のＢ^２は互いに同一でも異なっていてもよく、
ｎ２が２以上である場合、複数のＢ^６は互いに同一でも異なっていてもよく、
ｎ３が２以上である場合、複数のＢ^９は互いに同一でも異なっていてもよく、
ｎ４が２以上である場合、複数のＢ¹⁴は互いに同一でも異なっていてもよい。］ Among the compounds (1), compounds represented by any of the following formulas (1-1) to (1-6) are preferable.

[In equations (1-1) to (1-6),
B ^{1 to} B ²⁰ are independent of each other, a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a cyano group, a nitro group, and a substituted or unsubstituted amino group (substituted amino group and The definition of an unsubstituted amino group is as described above), and represents a chlorine atom or a trifluoromethyl group.
n1 to n4 represent integers 0 to 3 independently of each other.
When n1 is 2 or more, a plurality of B ^2s may be the same or different from each other.
If n2 is 2 or more, plural B ⁶ may be the same or different from each other,
If n3 is 2 or more, plural B ⁹ may be the same or different from each other,
When n4 is 2 or more, the plurality of B ^14s may be the same or different from each other. ]

［式（１−７）中、
Ｒ^１〜Ｒ^８は、互いに独立に、水素原子、−Ｒ^ｘ、−ＮＨ_２、−ＮＨＲ^ｘ、−ＮＲ^ｘ _２、−ＳＲ^ｘまたはハロゲン原子を表わす。
Ｒ^ｘは、炭素数１〜４のアルキル基または炭素数６〜１２のアリール基を表わす。］ As the anthraquinone dye, a compound represented by the formula (1-7) is preferable.

[In equation (1-7),
R ^{1 to} R ⁸ independently represent a hydrogen atom, -R ^x , -NH ₂ , -NHR ^x , -NR ^x ₂ , -SR ^x or a halogen atom.
R ^x represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 12 carbon atoms. ]

［式（１−８）中、
Ｒ^９〜Ｒ^１５は、互いに独立に、水素原子、−Ｒ^ｘ、−ＮＨ_２、−ＮＨＲ^ｘ、−ＮＲ^ｘ _２、−ＳＲ^ｘまたはハロゲン原子を表わす。
Ｒ^ｘは、炭素数１〜４のアルキル基または炭素数６〜１２のアリール基を表わす。］ As the oxazone dye, a compound represented by the formula (1-8) is preferable.

[In equation (1-8),
R ^{9 to} R ¹⁵ represent hydrogen atoms, -R ^x , -NH ₂ , -NHR ^x , -NR ^x ₂ , -SR ^x or halogen atoms independently of each other.
R ^x represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 12 carbon atoms. ]

［式（１−９）中、
Ｒ^１６〜Ｒ^２３は、互いに独立に、水素原子、−Ｒ^ｘ、−ＮＨ_２、−ＮＨＲ^ｘ、−ＮＲ^ｘ _２、−ＳＲ^ｘまたはハロゲン原子を表わす。
Ｒ^ｘは、炭素数１〜４のアルキル基または炭素数６〜１２のアリール基を表わす。］
式（１−７）、式（１−８）および式（１−９）において、Ｒ^ｘの炭素数１〜６のアルキル基としては、メチル基、エチル基、プロピル基、ブチル基、ペンチル基およびヘキシル基が挙げられ、炭素数６〜１２のアリール基としては、フェニル基、トルイル基、キシリル基およびナフチル基が挙げられる。 As the acridine dye, a compound represented by the formula (1-9) is preferable.

[In equation (1-9),
R ^{16 to} R ²³ independently represent a hydrogen atom, -R ^x , -NH ₂ , -NHR ^x , -NR ^x ₂ , -SR ^x or a halogen atom.
R ^x represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 12 carbon atoms. ]
In the formulas (1-7), (1-8) and (1-9), the alkyl group having 1 to 6 carbon atoms of R ^x includes a methyl group, an ethyl group, a propyl group, a butyl group and a pentyl group. And a hexyl group, and examples of the aryl group having 6 to 12 carbon atoms include a phenyl group, a toluyl group, a xsilyl group and a naphthyl group.

［式（１−１０）中、
Ｄ^１およびＤ^２は、互いに独立に、式（１−１０ａ）〜式（１−１０ｄ）のいずれかで表される基を表わす。

ｎ５は１〜３の整数を表わす。］

［式（２−１１）中、
Ｄ^３およびＤ^４は、互いに独立に、式（１−１１ａ）〜式（１−１１ｈ）のいずれかで表される基を表わす。

ｎ６は１〜３の整数を表わす。］ As the cyanine dye, a compound represented by the formula (1-10) and a compound represented by the formula (1-11) are preferable.

[In equation (1-10),
D ¹ and D ² represent groups represented by any of the formulas (1-10a) to (1-10d) independently of each other.

n5 represents an integer of 1 to 3. ]

[In equation (2-11),
D ³ and D ⁴ represent groups represented by any of the formulas (1-11a) to (1-11h) independently of each other.

n6 represents an integer of 1 to 3. ]

The polarizing layer is a coating layer. Further, the polarizing layer contains a composition (hereinafter, composition) containing one or more polymerizable liquid crystals (hereinafter, may be referred to as polymerizable liquid crystal (B)) that serve as a host compound in addition to the dichroic dye. It is preferably formed by applying (sometimes referred to as B) and polymerizing the polymerizable liquid crystal (B) in the obtained coating film.

The liquid crystal state indicated by the polymerizable liquid crystal (B) is preferably a smectic phase, and is more preferably a higher-order smectic phase in that a polarizing layer having a higher degree of orientation order can be produced. "Higher-order smectic phase" means smectic B phase, smectic D phase, smectic E phase, smectic F phase, smectic G phase, smectic H phase, smectic I phase, smectic J phase, smectic K phase and smectic L phase. Among them, the smectic B phase, the smectic F phase and the smectic I phase are more preferable. In a polarizing layer having a high degree of orientation order, a Bragg peak derived from a higher-order structure such as a hexatic phase or a crystal phase can be obtained by X-ray diffraction measurement. The "Bragg peak" means a peak derived from the plane periodic structure of molecular orientation, and a polarizing layer having a periodic interval of 3.0 to 5.0Å is preferable.

A polymerizable liquid crystal (B) exhibiting a smectic phase is referred to as a polymerizable smectic liquid crystal compound. Examples of the polymerizable smectic liquid crystal compound include a compound represented by the formula (B) (hereinafter, may be referred to as a compound (B)).
U ^1- V ^1- W ^1- X ^1- Y ^1- X ^2- Y ^2- X ^3- W ^2- V ^2- U ² (B)
[In formula (B),
X ¹ , X ² and X ³ represent, independently of each other, a 1,4-phenylene group which may have a substituent or a cyclohexane-1,4-diyl group which may have a substituent. However, at least one of X ¹ , X ² and X ³ is a 1,4-phenylene group which may have a substituent. -CH _2- constituting the cyclohexane-1,4-diyl group may be replaced with -O-, -S- or -NR-. R represents an alkyl group or a phenyl group having 1 to 6 carbon atoms.
Y ¹ and ^{Y 2,} independently of one _{another, -CH 2 CH 2 -, -} CH 2 O -, - COO -, - OCOO-, a single ^{bond, -N = N -, - CR} a = CR b -, - Represents C≡C− or CR ^a = N−. R ^a and R ^b represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms independently of each other.
U ¹ represents a hydrogen atom or a polymerizable group.
U ² represents a polymerizable group.
W ¹ and W ² represent single bonds, -O-, -S-, -COO- or OCOO- independently of each other.
V ¹ and V ² represent an alkanediyl group having 1 to 20 carbon atoms which may have a substituent independently of each other, and −CH ₂ − constituting the alkanediyl group is −O−, −. It may be replaced with S- or NH-. ]

It is preferable that at least two of X ¹ , X ² and X ³ are 1,4-phenylene groups which may have a substituent.

The 1,4-phenylene group which may have a substituent is preferably unsubstituted. The cyclohexane-1,4-diyl group which may have a substituent is preferably a trans-cyclohexane-1,4-diyl group which may have a substituent, and is a substituent. The trans-cyclohexane-1,4-diyl group which may have the above is preferably unsubstituted.

The substituents optionally contained in the 1,4-phenylene group which may have a substituent or the cyclohexane-1,4-diyl group which may have a substituent include a methyl group and an ethyl group. Examples thereof include an alkyl group having 1 to 4 carbon atoms such as a butyl group, a cyano group and a halogen atom.

Y ¹ is preferably -CH ₂ CH _2- , -COO- or a single bond, and Y ² is preferably -CH ₂ CH _2- or CH ₂ O-.

U ² is a polymerizable group. U ¹ is a hydrogen atom or a polymerizable group, preferably a polymerizable group. Both U ¹ and U ² are preferably polymerizable groups, and both are preferably photopolymerizable groups. The "photopolymerizable group" means a group that can participate in the polymerization reaction by an active radical, an acid, or the like generated from a photopolymerization initiator described later.

The photopolymerizable group represented by U ¹ and the polymerizable group represented by U ² may be different from each other, but are preferably the same type of group. Examples of the polymerizable group include a vinyl group, a vinyloxy group, a 1-chlorovinyl group, an isopropenyl group, a 4-vinylphenyl group, an acryloyloxy group, a methacryloyloxy group, an oxylanyl group and an oxetanyl group. Of these, an acryloyloxy group, a methacryloyloxy group, a vinyloxy group, an oxylanyl group and an oxetanyl group are preferable, and an acryloyloxy group is more preferable.

The alkanediyl groups represented by V ¹ and V ² include methylene group, ethylene group, propane-1,3-diyl group, butane-1,3-diyl group, butane-1,4-diyl group, and pentane-. 1,5-diyl group, hexane-1,6-diyl group, heptane-1,7-diyl group, octane-1,8-diyl group, decane-1,10-diyl group, tetradecane-1,14-diyl group Examples include groups and icosan-1,20-diyl groups. V ¹ and V ² are preferably an alkanediyl group having 2 to 12 carbon atoms, and more preferably an alkanediyl group having 6 to 12 carbon atoms.

Examples of the substituent arbitrarily contained in the alkanediyl group include a cyano group and a halogen atom, and the alkanediyl group is preferably unsubstituted and is an unsubstituted and linear alkanediyl group. Is more preferable.

W ¹ and W ² are independent of each other, preferably single bond or O−.

Examples of the compound (B) include compounds represented by the formulas (B-1) to (B-25). When compound (B) has a cyclohexane-1,4-diyl group, the cyclohexane-1,4-diyl group is preferably a trans form.

Among them, the formula (B-2), the formula (B-3), the formula (B-4), the formula (B-5), the formula (B-6), the formula (B-7), and the formula (B-8). , At least one selected from the group consisting of compounds represented by the formula (B-13), the formula (B-14), the formula (B-15), the formula (B-16) and the formula (B-17). preferable.

The exemplified polymerizable liquid crystal (B) can be used alone or in combination. Further, when two or more kinds of polymerizable liquid crystals are combined, it is preferable that at least one kind is a polymerizable liquid crystal (B), and more preferably two or more kinds are a polymerizable liquid crystal (B). By combining them, it may be possible to temporarily maintain the liquidity even at a temperature equal to or lower than the liquid crystal-crystal phase transition temperature. The mixing ratio when the two types of polymerizable liquid crystal compounds are combined is usually 1:99 to 50:50, preferably 5:95 to 50:50, and more preferably 10:90 to 50:50. Is.

The polymerizable liquid crystal (B) can be described, for example, by Luga Uruguaya Recl. Trav. Chim. It is produced by a known method described in Pays-Bas, 115, 321-328 (1996), or Japanese Patent No. 4719156.

The content ratio of the polymerizable liquid crystal (B) in the composition B is preferably 70 to 99.9% by mass, more preferably 80 to 99.9% by mass, based on the solid content of the composition. When the content ratio of the polymerizable liquid crystal (B) is within the above range, the orientation of the polymerizable liquid crystal (B) tends to be high. Here, the "solid content" refers to the total amount of the components excluding the volatile components such as the solvent from the composition B.

The content of the dichroic dye in the composition B can be appropriately adjusted according to the type of the dichroic dye and the like, but is 0.1 part by mass or more and 50 parts by mass with respect to 100 parts by mass of the polymerizable liquid crystal (B). The following is preferable, 0.1 part by mass or more and 20 parts by mass or less is more preferable, and 0.1 part by mass or more and 10 parts by mass or less is further preferable. When the content of the dichroic dye is within this range, the polymerizable liquid crystal (B) can be polymerized without disturbing the orientation. If the content of the dichroic dye is too large, the orientation of the polymerizable liquid crystal (B) may be hindered.

The composition B preferably contains a solvent. In general, since smectic liquid crystal compounds have a high viscosity, a composition containing a solvent is easy to apply, and as a result, a polarizing film is often easily formed. Examples of the solvent include the same solvents as those contained in the above-mentioned oriented polymer composition, and can be appropriately selected depending on the solubility of the polymerizable liquid crystal (B) and the dichroic dye.

The content of the solvent is preferably 50 to 98% by mass with respect to the total amount of the composition B. In other words, the solid content in the composition B is preferably 2 to 50% by mass.

The composition A and / or the composition B preferably contains one or more leveling agents. The leveling agent has a function of adjusting the fluidity of the composition B and flattening the coating film obtained by applying the composition B, and specific examples thereof include a surfactant. As the leveling agent, at least one selected from the group consisting of a leveling agent containing a polyacrylate compound as a main component and a leveling agent containing a fluorine atom-containing compound as a main component is preferable.

Examples of the leveling agent containing a polyacrylate compound as a main component include "BYK-350", "BYK-352", "BYK-353", "BYK-354", "BYK-355", "BYK-358N", and ". BYK-361N "," BYK-380 "," BYK-381 "and" BYK-392 "[BYK Chemie] can be mentioned.

Examples of the leveling agent containing a fluorine atom-containing compound as a main component include "Megafuck (registered trademark) R-08", "R-30", "R-90", "F-410", and "F". -411 "," F-443 "," F-445 "," F-470 "," F-471 "," F-477 "," F-479 "," F- 482 "and" F-483 "[DIC Corporation];" Surflon (registered trademark) S-381 "," S-382 "," S-383 "," S-393 "," SC-101 "," SC-105 "," KH-40 "and" SA-100 "[AGC Seimi Chemical Co., Ltd.];" E1830 "," E5844 "[Daikin Fine Chemical Laboratory Co., Ltd.];" Examples thereof include "Ftop EF301", "Ftop EF303", "Ftop EF351" and "Ftop EF352" [Mitsubishi Materials Electronics Chemical Co., Ltd.].

When the composition A and / or the composition B contains a leveling agent, the content thereof is preferably 0.05 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the polymerizable liquid crystal, and 0.05 parts by mass. It is more preferably 3 parts by mass or less. When the content of the leveling agent is within the above range, it is easy to horizontally orient the polymerizable liquid crystal, and the obtained polarizing layer tends to be smoother. When the content of the leveling agent with respect to the polymerizable liquid crystal is within the above range, the obtained polarizing layer tends to be less likely to have unevenness.

The composition A and / or the composition B preferably contains one or more polymerization initiators. The polymerization initiator is a compound capable of initiating the polymerization reaction of the polymerizable liquid crystal (B), and the photopolymerization initiator is preferable in that the polymerization reaction can be started under lower temperature conditions. Specific examples thereof include photopolymerization initiators capable of generating active radicals or acids by the action of light, and among them, photopolymerization initiators that generate radicals by the action of light are preferable.

Examples of the polymerization initiator include benzoin compounds, benzophenone compounds, alkylphenone compounds, acylphosphine oxide compounds, triazine compounds, iodonium salts and sulfonium salts.

Examples of the benzoin compound include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether and benzoin isobutyl ether.

Examples of the benzophenone compound include benzophenone, methyl o-benzoyl benzoate, 4-phenylbenzophenone, 4-benzoyl-4'-methyldiphenylsulfide, 3,3', 4,4'-tetra (tert-butylperoxycarbonyl) benzophenone. And 2,4,6-trimethylbenzophenone.

Examples of the alkylphenone compound include diethoxyacetophenone, 2-methyl-2-morpholino-1- (4-methylthiophenyl) propan-1-one, and 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butane. -1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1,2-diphenyl-2,2-dimethoxyethane-1-one, 2-hydroxy-2-methyl-1-[ 4- (2-Hydroxyethoxy) phenyl] propan-1-one, 1-hydroxycyclohexylphenylketone and 2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl] propan-1-one Examples include oligomers.

Acylphosphine oxide compounds include 2,4,6-trimethylbenzoyldiphenylphosphine oxide and bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide.

Examples of the triazine compound include 2,4-bis (trichloromethyl) -6- (4-methoxyphenyl) -1,3,5-triazine and 2,4-bis (trichloromethyl) -6- (4-methoxynaphthyl). -1,3,5-triazine, 2,4-bis (trichloromethyl) -6- (4-methoxystyryl) -1,3,5-triazine, 2,4-bis (trichloromethyl) -6- [2 -(5-Methylfuran-2-yl) ethenyl] -1,3,5-triazine, 2,4-bis (trichloromethyl) -6- [2- (fran-2-yl) ethenyl] -1,3 , 5-Triazine, 2,4-bis (trichloromethyl) -6- [2- (4-diethylamino-2-methylphenyl) ethenyl] -1,3,5-triazine and 2,4-bis (trichloromethyl) -6- [2- (3,4-dimethoxyphenyl) ethenyl] -1,3,5-triazine can be mentioned.

Commercially available polymerization initiators can be used. Commercially available polymerization initiators include "Irgacure (registered trademark) 907", "Irgacure (registered trademark) 184", "Irgacure (registered trademark) 651", "Irgacure (registered trademark) 819", and "Irgacure (registered trademark) 819". "Registered Trademark" 250 "," Irga Cure (Registered Trademark) 369 "(Ciba Japan Co., Ltd.);" Sakeol (Registered Trademark) BZ "," Sakeall (Registered Trademark) Z "," Sakeall (Registered Trademark) BEE " Seiko Kagaku Co., Ltd.; "Kayacure (registered trademark) BP100" (Nippon Kayaku Co., Ltd.); "Kayacure (registered trademark) UVI-6992" (manufactured by Dow); "Adecaoptomer SP-152" "," Adecaoptomer SP-170 "(ADEKA Co., Ltd.);" TAZ-A "," TAZ-PP "(Nippon Sibel Hegner); and" TAZ-104 "(Sanwa Chemical Co., Ltd.).

When the composition A and / or the composition B contains a polymerization initiator, the content thereof can be appropriately adjusted according to the type and amount of the polymerizable liquid crystal contained in the composition, but the polymerizable liquid crystal 100 With respect to parts by mass, 0.1 to 30 parts by mass is preferable, 0.5 to 10 parts by mass is more preferable, and 0.5 to 8 parts by mass is further preferable. When the content of the polymerizable initiator is within this range, the polymerizable liquid crystal (B) can be polymerized without disturbing the orientation.

When the composition A and / or the composition B contains a photopolymerization initiator, the composition may further contain a photosensitizer. Photosensitizers include xanthone compounds such as xanthone, thioxanthone (eg, 2,4-diethylthioxanthone, 2-isopropylthioxanthone, etc.); anthracene, alkoxy group-containing anthracene (eg, dibutoxyanthracene, etc.); Examples include phenothiazine and rubrene.

When the composition A and / or the composition B contains a photopolymerization initiator and a photosensitizer, the polymerization reaction of the polymerizable liquid crystal contained in the composition can be further promoted. The amount of the photosensitizer used can be appropriately adjusted according to the type and amount of the photopolymerization initiator and the polymerizable liquid crystal, but is preferably 0.1 to 30 parts by mass with respect to 100 parts by mass of the polymerizable liquid crystal. 0.5 to 10 parts by mass is more preferable, and 0.5 to 8 parts by mass is further preferable.

In order to allow the polymerization reaction of the polymerizable liquid crystal to proceed more stably, the composition A and / or the composition B may contain an appropriate amount of a polymerization inhibitor, whereby the degree of progress of the polymerization reaction of the polymerizable liquid crystal It becomes easier to control.

Polymerization inhibitors include radical supplements such as hydroquinone, alkoxy group-containing hydroquinone, alkoxy group-containing catechol (eg, butyl catechol), pyrogallol, 2,2,6,6-tetramethyl-1-piperidinyloxyrades. Thiophenols; β-naphthylamines and β-naphthols.

When the composition A and / or the composition B contains a polymerization inhibitor, the content thereof can be appropriately adjusted according to the type and amount of the polymerizable liquid crystal, the amount of the photosensitizer used, and the like. 0.1 to 30 parts by mass is preferable, 0.5 to 10 parts by mass is more preferable, and 0.5 to 8 parts by mass is further preferable with respect to 100 parts by mass of the liquid crystal. When the content of the polymerization inhibitor is within this range, the polymerizable liquid crystal can be polymerized without disturbing the orientation.

The polarizing layer is usually formed by applying the composition B on a base material, an alignment film or a retardation layer, and polymerizing the polymerizable liquid crystal (B) in the obtained coating film. The method of applying the composition is not limited. Examples of the alignment film include those similar to those described above.

A dry film is formed by applying the composition B and drying and removing the solvent under the condition that the polymerizable liquid crystal (B) contained in the obtained coating film does not polymerize. Examples of the drying method include a natural drying method, a ventilation drying method, a heat drying method and a vacuum drying method. When the polymerizable liquid crystal (B) is a polymerizable smectic liquid crystal compound, it is preferable that the liquid crystal state of the polymerizable smectic liquid crystal compound contained in the dry film is changed to the nematic phase (nematic liquid crystal state) and then transferred to the smectic phase. In order to form a smectic phase via the nematic phase, for example, the dry coating is heated above a temperature at which the polymerizable smectic liquid crystal compound contained in the dry coating undergoes a phase transition to the liquid crystal state of the nematic phase, and then the polymerizable smectic is formed. A method is adopted in which the liquid crystal compound is cooled to a temperature indicating the liquid crystal state of the smectic phase.

Next, a method of changing the liquid crystal state of the polymerizable liquid crystal (B) in the dry film to the smectic phase and then photopolymerizing the polymerizable liquid crystal (B) while maintaining the liquid crystal state of the smectic phase will be described. In photopolymerization, the light irradiating the dry film includes the type of photopolymerization initiator contained in the dry film and the type of polymerizable liquid crystal (B) (particularly, the photopolymerizable group contained in the polymerizable liquid crystal (B). Type) and its amount are appropriately selected, and specific examples thereof include light and active electron beam selected from the group consisting of visible light, ultraviolet light, and laser light. Of these, ultraviolet light is preferable because it is easy to control the progress of the polymerization reaction and it is possible to use a photopolymerization apparatus widely used in the art. Therefore, it is preferable to select the type of the polymerizable liquid crystal (B) and the photopolymerization initiator contained in the composition B so that the composition can be photopolymerized by ultraviolet light. Further, at the time of polymerization, the polymerization temperature can be controlled by irradiating light while cooling the dry film by an appropriate cooling means. By adopting such a cooling means, if the polymerizable liquid crystal (B) is polymerized at a lower temperature, a polarizing layer can be appropriately formed even if a base material having a relatively low heat resistance is used. A patterned polarizing layer can also be obtained by masking or developing during photopolymerization.

By performing photopolymerization, the polymerizable liquid crystal (B) is polymerized while maintaining the liquid crystal state of the smectic phase, preferably the higher-order smectic phase, to form a polarizing layer. The polarizing layer obtained by polymerizing the polymerizable liquid crystal (B) while maintaining the liquid crystal state of the smectic phase is a conventional host-guest type polarizing film, that is, a nematic phase liquid crystal due to the action of the dichroic dye. There is an advantage that the polarization performance is high as compared with the polarizing film composed of states. Further, there is an advantage that the strength is excellent as compared with the one coated only with the dichroic dye or the lyotropic liquid crystal.

The slow axis of the retardation layer and the absorption axis of the polarizing layer in this circular polarizing plate are neither parallel to each other nor orthogonal to each other. In order to exhibit a good function as a circular polarizing plate, it is preferable that the angle formed by the slow axis of the retardation layer and the absorption axis of the polarizing layer is substantially 45 °.

When the present circular polarizing plate is manufactured, the order in which the retardation layer and the polarizing layer are formed is arbitrary. After forming the retardation layer on the base material, the polarizing layer may be formed on the retardation layer. After forming the polarizing layer on the base material, a retardation layer may be formed on the polarizing layer. A polarizing layer may be formed on one surface of the substrate, and a retardation layer may be formed on the other surface of the substrate. An alignment film may be formed between the base material and the retardation layer, the base material and the polarizing layer, and / or between the base material and the polarizing layer.

When a polarizing layer is formed on the retarding layer after forming the retarding layer on the base material, a protective layer is formed on the retarding layer and a polarizing layer is formed on the protective layer, if necessary. It may be formed. An alignment film may be formed on the protective layer, and a polarizing layer may be formed on the alignment film. Further, after forming a polarizing layer on the base material, a protective layer may be formed on the polarizing layer, and a retardation layer may be formed on the protective layer. An alignment film may be formed on the early protective layer, and a retardation layer may be formed on the alignment film.

The protective layer is usually an acrylic oligomer or polymer composed of polyfunctional acrylate (methacrylate), urethane acrylate, polyester acrylate, epoxy acrylate, etc., polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polyvinylpyrrolidone, starches, methylcellulose, carboxy. It is preferably formed from a composition for forming a protective layer containing a water-soluble polymer such as methyl cellulose or sodium alginate and a solvent.

Examples of the solvent contained in the composition for forming the protective layer are the same as those described above, and among them, at least one solvent selected from the group consisting of water, alcohol solvent and ether solvent forms the protective layer. It is preferable in that it does not dissolve the layer. Examples of the alcohol solvent include methanol, ethanol, butanol, ethylene glycol, isopropyl alcohol, propylene glycol, ethylene glycol methyl ether, ethylene glycol butyl ether and propylene glycol monomethyl ether. Examples of the ether solvent include ethylene glycol monomethyl ether acetate and propylene glycol monomethyl ether acetate. Of these, ethanol, isopropyl alcohol, propylene glycol monomethyl ether and propylene glycol monomethyl ether acetate are preferable.

The thickness of the protective layer is usually 20 μm or less. The thickness of the protective layer is preferably 0.5 μm or more and 9.5 μm or less, and more preferably 1 μm or more and 5 μm or less. The thickness of the protective layer can usually be determined by measurement with an interference film thickness meter, a laser microscope or a stylus film thickness meter.

The circular polarizing plate may further have an adhesive layer on the surface of the retardation layer or the polarizing layer formed on the surface of the circular polarizing plate. Further, a primer layer may be provided between the retardation layer or the polarizing layer and the pressure-sensitive adhesive layer.
The pressure-sensitive adhesive layer is formed from a pressure-sensitive adhesive, and the pressure-sensitive adhesive usually contains a polymer and may contain a solvent.

Examples of the polymer include acrylic polymers, silicone-based polymers, polyesters, polyurethanes, and polyethers. Among them, the acrylic adhesive containing an acrylic polymer has excellent optical transparency, retains appropriate wettability and cohesive force, has excellent adhesion, and has high weather resistance and heat resistance, and is heated. It is preferable because peeling problems such as floating and peeling are unlikely to occur under humid conditions.

The acrylic polymer is a (meth) acrylate in which the alkyl group of the ester portion is an alkyl group having 20 or less carbon atoms such as a methyl group, an ethyl group or a butyl group (hereinafter, acrylate and methacrylate are collectively referred to as (meth)). Acrylate, acrylic acid and methacrylic acid are sometimes collectively referred to as (meth) acrylic acid), and (meth) acrylic monomer having a functional group such as (meth) acrylic acid or hydroxyethyl (meth) acrylate. Copolymer is preferred.
The pressure-sensitive adhesive containing such a copolymer has excellent adhesiveness, and even when it is peeled off after being attached to the display device, it is relatively easy without causing adhesive residue on the display device. It is preferable because it can be peeled off. The glass transition temperature of the acrylic polymer is preferably 25 ° C. or lower, more preferably 0 ° C. or lower. The weight average molecular weight of such an acrylic polymer is preferably 100,000 or more.

Examples of the solvent include the solvents mentioned as the solvents for the oriented polymer composition.

Further, the pressure-sensitive adhesive may contain a light diffusing agent. The light diffusing agent is for imparting light diffusing property to the pressure-sensitive adhesive layer, and may be fine particles having a refractive index different from that of the polymer contained in the pressure-sensitive adhesive layer, and the light-diffusing agent is made of an inorganic compound. Examples thereof include fine particles and fine particles made of an organic compound (polymer). Since the base polymer constituting the pressure-sensitive adhesive layer including the acrylic polymer exhibits a refractive index of about 1.4, the light diffusing agent may be appropriately selected from those having a refractive index of about 1 to 2. Good. The difference in refractive index between the polymer contained in the pressure-sensitive adhesive as an active ingredient and the light diffusing agent is usually 0.01 or more, and from the viewpoint of brightness and visibility of the liquid crystal display device, it is 0.01 or more and 0.5 or less. Is preferable. The fine particles used as the light diffusing agent are preferably spherical, which is also close to monodisperse, and for example, fine particles having an average particle size in the range of about 2 to 6 μm are preferably used.

The index of refraction is measured by the general minimum argument method or Abbe refractometer.

Examples of the fine particles made of the inorganic compound include aluminum oxide (refractive index 1.76) and silicon oxide (refractive index 1.45).

Examples of fine particles made of an organic compound (polymer) include melamine beads (refractive index 1.57), polymethyl methacrylate beads (refractive index 1.49), and methyl methacrylate / styrene copolymer resin beads (refractive index). Rate 1.50 to 1.59), Polycarbonate beads (refractive index 1.55), polyethylene beads (refractive index 1.53), polystyrene beads (refractive index 1.6), polyvinyl chloride beads (refractive index 1.46) ), Silicone resin beads (refractive index 1.46), and the like.

The blending amount of the light diffusing agent is appropriately determined in consideration of the haze value required for the pressure-sensitive adhesive layer in which the light diffusing agent is dispersed, the brightness of the liquid crystal display device to which the light diffusing agent is applied, and the like. It is about 3 to 30 parts by weight with respect to 100 parts by weight of the resin constituting the agent layer.

The haze value of the pressure-sensitive adhesive layer in which the light diffusing agent is dispersed ensures the brightness of the liquid crystal display device to which the circularly polarizing plate provided with the pressure-sensitive adhesive layer is applied, and also prevents the display image from bleeding or blurring. Therefore, it is preferable that the range is 20 to 80%. The haze value is a value expressed by (diffusion transmittance / total light transmittance) × 100 (%), and is measured according to JIS ° K ° 7105.

The thickness of the pressure-sensitive adhesive layer is determined according to the adhesive force and the like and is not particularly limited, but is usually about 1 to 40 μm. In order to obtain a circularly polarizing plate provided with a thin pressure-sensitive adhesive layer without impairing properties such as workability and durability, the thickness of the pressure-sensitive adhesive layer is preferably about 3 to 25 μm. Further, by setting the thickness of the adhesive layer to about 3 to 25 μm, it is possible to maintain the brightness when the liquid crystal display device is viewed from the front or when viewed from an angle, and to prevent bleeding or blurring of the display image. it can.

The primer layer usually contains a transparent resin and is formed from a transparent resin solution. The primer layer can suppress defects in the retardation layer or the polarizing layer when forming the pressure-sensitive adhesive layer. As the transparent resin, those having excellent coatability and excellent transparency and adhesion after forming the primer layer are preferable.

The solvent of the transparent resin solution includes aromatic hydrocarbon solvents such as benzene, toluene and xylene; ketone solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone; ethyl acetate, isobutyl acetate and the like, depending on the transparency of the solvent. Ester solvent; Chlorinated hydrocarbon solvent such as methylene chloride, trichloroethylene and chloroform; General organic solvent such as alcohol solvent such as ethanol, 1-propanol, 2-propanol and 1-butanol can be used, but the organic solvent can be used. Since forming the primer layer using a transparent resin solution containing the above may affect the optical properties of the liquid crystal cured film, it is preferable to form the primer layer using a solution using water as a solvent.

Examples of the transparent resin include epoxy resins. The epoxy resin may be a one-component curing type or a two-component curing type. A water-soluble epoxy resin is particularly preferable. The water-soluble epoxy resin is a polyamide epoxy resin obtained by reacting epichlorohydrin with a polyamide polyamine obtained by reacting a polyalkylene polyamine such as diethylenetriamine or triethylenetetramine with a dicarboxylic acid such as adipic acid. Can be mentioned. Examples of commercially available products of such polyamide epoxy resin include Sumire's Resin (registered trademark) 650 (30) and Sumire's Resin (registered trademark) 675 (registered trademark) sold by Sumika Chemtex Co., Ltd.

When a water-soluble epoxy resin is used as the transparent resin, it is preferable to use another water-soluble resin such as a polyvinyl alcohol-based resin in combination in order to further improve the coatability. Polyvinyl alcohol-based resins are modified polyvinyls such as partially saponified polyvinyl alcohol, fully saponified polyvinyl alcohol, carboxyl group-modified polyvinyl alcohol, acetoacetyl group-modified polyvinyl alcohol, methylol group-modified polyvinyl alcohol, and amino group-modified polyvinyl alcohol. It may be an alcohol-based resin. Examples of suitable commercially available polyvinyl alcohol-based resins include KL-318 (trade name), which is an anionic group-containing polyvinyl alcohol sold by Kuraray Co., Ltd.

When the primer layer is formed from a solution containing a water-soluble epoxy resin, the epoxy resin is preferably in the range of about 0.2 to 1.5 parts by weight with respect to 100 parts by weight of water. When a polyvinyl alcohol-based resin is mixed with this solution, the amount thereof is preferably about 1 to 6 parts by weight with respect to 100 parts by weight of water. The thickness of the primer layer is preferably in the range of about 0.1 to 10 μm.

The method for forming the primer layer is not limited, and various known coating methods such as a direct gravure method, a reverse gravure method, a die coating method, a comma coating method, and a bar coating method can be used.

The pressure-sensitive adhesive layer can be formed by applying the pressure-sensitive adhesive to the surface of a retardation layer, a polarizing layer or a primer layer and drying the pressure-sensitive adhesive layer. A method in which an adhesive layer is formed by applying and drying, and then the film with the adhesive layer is attached to the surface of a retardation layer, a polarizing layer or a primer layer so that the adhesive layer side is the bonding surface. Can also be formed by. It is preferable that the surface of the primer layer on which the pressure-sensitive adhesive layer is formed is subjected to a corona discharge treatment in advance. Thereby, the adhesion between the primer layer and the pressure-sensitive adhesive layer can be further improved.

Examples of the method of applying the pressure-sensitive adhesive include the same methods as those exemplified as the method of applying the oriented polymer composition to the substrate. Examples of the method for removing the solvent from the applied pressure-sensitive adhesive include the same method as the method for removing the solvent from the oriented polymer composition.

The peel strength of the circularly polarizing plate having the pressure-sensitive adhesive layer on the surface is measured as follows.
A test piece having a width of 25 mm and a length of about 200 mm is cut from this circular polarizing plate having a pressure-sensitive adhesive layer on its surface, the pressure-sensitive adhesive surface is bonded to a glass plate, and then the test piece is subjected to a tensile tester. Grasp one end in the length direction (one side with a width of 25 mm), in an atmosphere with a temperature of 23 ° C and a relative humidity of 60%, at a cross head speed (grasping movement speed) of 200 mm / min, JIS K 6854-1: 1999 "Adhesive-peeling" Perform a 90 ° peeling test in accordance with "Adhesion strength test method-Part 1: 90 degree peeling".
The peel strength (F1) between the base material and the first alignment film in the circular polarizing plate having the base material, the first alignment film, the polarizing layer, the second alignment film, the retardation layer and the pressure-sensitive adhesive layer in this order is , More than the peel strength between the first alignment film and the polarizing layer (F2), the peel strength between the second alignment film and the retardation layer (F3), and the peel strength between the retardation layer and the pressure-sensitive adhesive layer (F4). Low is preferable. The peel strength (F1) can be adjusted by the base material and the first alignment film.
For example, a base material having a functional group forming a chemical bond with the alignment film on the surface tends to have a high peel strength (F1) between the base material and the first alignment film. Therefore, as the base material for lowering the peel strength (F1), a base material having few functional groups on the surface is preferable, and a base material not subjected to surface treatment for forming functional groups on the surface is preferable.
Further, the alignment film having a functional group forming a chemical bond with the base material tends to have a high peel strength (F1) between the base material and the first alignment film. Therefore, as the alignment film for lowering the peel strength (F1), an alignment film having few functional groups forming a chemical bond with the base material is preferable. Further, in order to lower (F1), it is preferable that the orientation polymer composition or the composition for forming a photoalignment film does not contain a reagent for cross-linking the base material and the alignment film, and further, the base material is used. It is preferable that it does not contain components such as a solvent that dissolves. The peeling strength (F1) between the base material and the first alignment film tends to increase due to the dissolution of the surface of the base material by the orientation polymer composition or the composition for forming a photoalignment film.
In order to increase the peel strength (F2), (F3) and (F4), the first alignment film and the polarizing layer, the second alignment film and the retardation layer, and the retardation layer and the pressure-sensitive adhesive layer are used. A chemical bond may be formed between them.

By removing the base material from the circular polarizing plate having the pressure-sensitive adhesive layer on the surface, a circularly polarizing film having the pressure-sensitive adhesive layer can be obtained. Any method can be mentioned as a method for removing the base material.
The thickness of the circularly polarizing film having the pressure-sensitive adhesive layer is usually 5 μm or more and 15 μm or less, preferably 5 μm or more and 10 μm or less. The thickness of the circularly polarizing film having the pressure-sensitive adhesive layer can usually be determined by measurement with an interference film thickness meter, a laser microscope or a stylus film thickness meter.

Subsequently, a method for continuously producing the present circular polarizing plate will be described. A suitable method for continuously producing such a circularly polarizing plate includes a roll-to-roll method.

In particular,
(1) A process of preparing a roll in which a base material is wound around a core.
(2) A step of continuously delivering the base material from the roll,
(3) A step of continuously forming an alignment film on the substrate,
(4) A step of applying the composition A on the alignment film to continuously form a retardation layer.
(5) A step of continuously forming a protective layer on the retardation layer of the roll obtained in (4) above.
(6) A step of applying an alignment film on the protective layer obtained in (5) above to continuously form the alignment film.
(7) A step of applying the composition B on the alignment film obtained in (6) above to continuously form a polarizing layer.
(8) A step of laminating a film with an adhesive layer on the polarizing layer obtained in (7) above so that the adhesive layer side is a laminating surface.
(9) Examples thereof include a method in which the continuously obtained circularly polarizing plate is wound around a second winding core and the steps of obtaining a second roll are sequentially performed. The steps (5) and (8) may be omitted if necessary.

Also,
(1a) Step of preparing a roll in which a base material is wound around a core,
(2a) A step of continuously delivering the base material from the roll,
(3a) A step of continuously forming an alignment film on the substrate,
(4a) A step of applying the composition B on the alignment film to continuously form a polarizing layer.
(5a) A step of continuously forming a protective layer on the polarizing layer of the roll obtained in (4a) above, (6a) Applying an alignment film on the protective layer obtained in (5a) above and continuing. The process of forming
(7a) A step of applying the composition A on the alignment film obtained in the above (6a) to continuously form a retardation layer.
(8a) A step of laminating a film with an adhesive layer on the retardation layer obtained in (7a) above so that the adhesive layer side is a laminating surface.
(9a) There is also a method in which the steps of winding the continuously obtained circularly polarizing plate around the second winding core and obtaining the second roll are performed in order. The steps (5a) and (8a) may be omitted if necessary.

Also,
(1b) A step of preparing a roll in which a base material is wound around a core.
(2b) A step of continuously delivering the base material from the roll,
(3b) A step of continuously forming an alignment film on the substrate,
(4b) A step of applying the composition A on the alignment film to continuously form a retardation layer.
(5b) A step of applying an alignment film on the surface of the roll obtained in (4b) opposite to the retardation layer and continuously forming the alignment film.
(6b) A step of applying the composition B on the alignment film obtained in (5b) above to continuously form a polarizing film.
(7b) There is also a method in which the steps of winding the continuously obtained circularly polarizing plate around the second winding core and obtaining the second roll are performed in order.

Also,
(1c) A step of preparing a roll in which a transparent base material is wound around a core.
(2c) A step of continuously delivering the transparent base material from the roll,
(3c) A step of continuously forming an alignment film on the transparent substrate,
(4c) A step of applying a composition containing the composition B on the alignment film to continuously form a polarizing layer.
(5c) A step of continuously forming an alignment film on the surface opposite to the polarizing layer of the roll obtained in (4c) above.
(6c) A step of applying the composition A on the alignment film obtained in the above (5c) to continuously form a retardation layer.
(7c) There is also a method in which the steps of winding the continuously obtained circularly polarizing plate around the second winding core and obtaining the second roll are performed in order.

FIG. 1 shows a schematic view of the circularly polarizing plate. FIG. 1A is a circular polarizing plate in which a base material, a retardation layer, and a polarizing layer are laminated in this order. FIG. 1B is a circularly polarizing plate in which a base material, a polarizing layer, and a retardation layer are laminated in this order.

This circularly polarizing plate can be used in various display devices. Further, the circularly polarizing plate having the pressure-sensitive adhesive layer on the surface can be used for manufacturing various display devices. Specifically, by attaching a circular polarizing plate having a pressure-sensitive adhesive layer on the surface to the display surface of the display device via the pressure-sensitive adhesive layer, a display device having the present circularly polarizing plate can be obtained. By removing the base material, a display device with a circularly polarizing film provided with the circularly polarizing film of the present invention can be obtained.
The display device is a device having a display element, and includes a light emitting element or a light emitting device as a light emitting source. Display devices include liquid crystal display devices, organic electroluminescence (EL) display devices, inorganic electroluminescence (EL) display devices, touch panel display devices, electron emission display devices (for example, electric field emission display devices (FED), surface electric field emission display devices). (SED)), electronic paper (display device using electronic ink or electrophoretic element, plasma display device, projection type display device (for example, grating light valve (GLV) display device, display device having a digital micromirror device (DMD)). ) And piezoelectric ceramic displays. The liquid crystal display device includes any of a transmissive liquid crystal display device, a transflective liquid crystal display device, a reflective liquid crystal display device, a direct-view liquid crystal display device, a projection type liquid crystal display device, and the like. These display devices may be display devices that display two-dimensional images or three-dimensional display devices that display three-dimensional images. In particular, organic electroluminescence (EL) display devices or inorganic electro. It can be effectively used as a display device of a luminescent (EL) display device.

FIG. 2 is a schematic view showing a liquid crystal display device 10 which is one of the display devices of the present invention. The liquid crystal layer 15 is sandwiched between two substrates 12a and 12b. A color filter 13 is arranged on the liquid crystal layer 15 side of the substrate 12a. The color filter 13 is arranged at a position facing the pixel electrodes 20 across the liquid crystal layer 15, and the black matrix 18 is arranged at a position facing the boundary between the pixel electrodes. A transparent electrode 14 covers them. An overcoat layer may be provided between the color filter 13 and the transparent electrode 14.

The thin film transistor 19 and the pixel electrode 20 are regularly arranged on the liquid crystal layer 15 side of the substrate 12b. The pixel electrodes 20 are arranged at positions facing the color filter 13 with the liquid crystal layer 15 in between. An interlayer insulating film 16 having a connection hole (not shown) is arranged between the thin film transistor 19 and the pixel electrode 20.

Examples of the substrate 12a and the substrate 12b include a glass substrate and a plastic substrate. When the color filter 13 and the thin film transistor 19 formed on these substrates need to be heated to a high temperature, the substrates 12a and 12b are preferably glass substrates.

Examples of the thin film transistor 19 include a high-temperature polysilicon transistor formed on a quartz substrate, a low-temperature polysilicon transistor formed on a glass substrate, and an amorphous silicon transistor formed on a glass substrate or a plastic substrate. The driver IC may be formed on the substrate 12b in order to reduce the size of the liquid crystal display device.

A liquid crystal layer 15 is arranged between the transparent electrode 14 and the pixel electrode 20. A spacer 21 is formed on the liquid crystal layer 15 in order to keep the distance between the substrate 12a and the substrate 12b constant. Of the layers formed on the substrate 12a and the substrate 12b, on the surface in contact with the liquid crystal layer 15, an alignment film for orienting the liquid crystal compound contained in the liquid crystal layer 15 in a desired direction may be arranged.

Each member is laminated in the order of the substrate 12a, the color filter 13 and the black matrix 18, the transparent electrode 14, the liquid crystal layer 15, the pixel electrode 20, the interlayer insulating film 16 and the thin film transistor 19, and the substrate 12b.

The circular polarizing plate 11a and the circular polarizing plate 11b are laminated on the outside of the substrate 12a and the substrate 12b sandwiching the liquid crystal layer 15. A backlight unit 17, which is a light emitting source, is arranged outside the circularly polarizing plate 11b. The backlight unit 17 includes a light source, a light guide, a reflector, a diffusion sheet, and a viewing angle adjusting sheet. As the light source, various light sources such as electroluminescence (EL), cold cathode fluorescent lamp, hot cathode fluorescent lamp, light emitting diode (LED), laser light source, and mercury lamp can be used.

FIG. 3 is a schematic view showing an organic EL display device 30 which is one of the display devices of the present invention. The organic EL display device 30 of the present invention shown in FIG. 3A includes the circular polarizing plate 31, and has a light emitting layer on a substrate 32 on which a pixel electrode 34 is formed via an interlayer insulating film 33. 35 and the cathode electrode 36 are laminated. The circularly polarizing plate 31 is arranged on the side opposite to the light emitting layer 35 with the substrate 32 interposed therebetween. The light emitting layer 35 emits light by applying a positive voltage to the pixel electrode 34 and a negative voltage to the cathode electrode 36 and applying a direct current between the pixel electrode 34 and the cathode electrode 36. The light emitting layer 35 is composed of an electron transport layer, a light emitting layer, a hole transport layer, and the like. The light emitted from the light emitting layer 35 passes through the pixel electrode 34, the interlayer insulating film 33, the substrate 32, and the circularly polarizing plate 31.

In order to manufacture the organic EL display device 30, first, the thin film transistor 38 is formed on the substrate 32 in a desired shape. Then, the interlayer insulating film 33 is formed, and then the pixel electrode 34 is formed by a sputtering method and patterned. After that, the light emitting layer 35 is laminated.

Next, the circular polarizing plate 31 is provided on the surface of the substrate 32 opposite to the surface on which the thin film transistor 38 is provided. In that case, the 1/4 wavelength layer of the circular polarizing plate 31 is arranged so as to be on the substrate 32 side.

Examples of the substrate 32 include a sapphire glass substrate, a quartz glass substrate, a soda glass substrate, a ceramic substrate such as alumina; a metal substrate such as copper; and a plastic substrate. Although not shown, a heat conductive film may be formed on the substrate 32. Examples of the heat conductive film include a diamond thin film (DLC and the like). When the pixel electrode 34 is of the reflective type, light is emitted in the direction opposite to that of the substrate 32. Therefore, not only a transparent material but also a non-transparent material such as stainless steel can be used. The substrate may be formed as a single substrate, or may be formed as a laminated substrate by bonding a plurality of substrates with an adhesive. Further, these substrates are not limited to plate-shaped ones, and may be films.

As the thin film transistor 38, for example, a polycrystalline silicon transistor or the like may be used. The thin film transistor 38 is provided at the end of the pixel electrode 34, and its size is about 10 to 30 μm. The size of the pixel electrode 34 is about 20 μm × 20 μm to 300 μm × 300 μm.

A wiring electrode for the thin film transistor 38 is provided on the substrate 32. The wiring electrode has a low resistance and has a function of electrically connecting to the pixel electrode 34 to keep the resistance value low. Generally, the wiring electrode is Al, Al and a transition metal (excluding Ti), Ti or Those containing any one or more of titanium nitride (TiN) are used.

An interlayer insulating film 33 is provided between the thin film transistor 38 and the pixel electrode 34. The interlayer insulating film 33 is formed by depositing an inorganic material such as silicon oxide such as SiO ₂ or silicon nitride by sputtering or vacuum deposition, a silicon oxide layer formed by SOG (spin on glass), a photoresist, or polyimide. And any one having insulating properties such as a coating film of a resin-based material such as acrylic resin may be used.

The rib 39 is formed on the interlayer insulating film 33. The rib 39 is arranged at the peripheral portion (between adjacent pixels) of the pixel electrode 34. Examples of the material of the rib 39 include acrylic resin and polyimide resin. The thickness of the rib 39 is preferably 1.0 μm or more and 3.5 μm, and more preferably 1.5 μm or more and 2.5 μm or less.

Next, an EL element including a pixel electrode 34, a light emitting layer 35, and a cathode electrode 36 will be described. The light emitting layer 35 has at least one hole transport layer and a light emitting layer, respectively, and has, for example, an electron injection transport layer, a light emitting layer, a hole transport layer, and a hole injection layer in that order.

Examples of the pixel electrode 34 include ITO (tin-doped indium oxide), IZO (zinc-doped indium oxide), IGZO, ZnO, SnO ₂ and In ₂ O ₃ , but ITO and IZO are particularly preferable. The thickness of the pixel electrode 35 may be a certain thickness or more capable of sufficiently injecting holes, and is preferably about 10 to 500 nm.

The pixel electrode 34 can be formed by a vapor deposition method (preferably a sputtering method). The sputter gas is not particularly limited, and an inert gas such as Ar, He, Ne, Kr and Xe, or a mixed gas thereof may be used.

As the constituent material of the cathode electrode 36, for example, metal elements such as K, Li, Na, Mg, La, Ce, Ca, Sr, Ba, Al, Ag, In, Sn, Zn and Zr may be used. In order to improve the operational stability of the electrode, it is preferable to use a two-component or three-component alloy system selected from the exemplified metal elements. Examples of the alloy system include Ag · Mg (Ag: 1 to 20 at%), Al · Li (Li: 0.3 to 14 at%), In · Mg (Mg: 50 to 80 at%) and Al · Ca (Ca:: 5 to 20 at%) and the like are preferable.

The cathode electrode 36 is formed by a vapor deposition method, a sputtering method, or the like. The thickness of the cathode electrode 37 is preferably 0.1 nm or more, preferably 1 to 500 nm or more.

The hole injection layer has a function of facilitating the injection of holes from the pixel electrode 34, and the hole transport layer has a function of transporting holes and a function of hindering electrons, and has a function of transporting holes and a function of hindering electrons. Also called the transport layer.

The thickness of the light emitting layer, the combined thickness of the hole injection layer and the hole transport layer, and the thickness of the electron injection transport layer are not particularly limited and vary depending on the forming method, but should be about 5 to 100 nm. Is preferable. Various organic compounds can be used for the hole injection layer and the hole transport layer. A vacuum vapor deposition method can be used to form the hole injection transport layer, the light emitting layer, and the electron injection transport layer because a homogeneous thin film can be formed.

The light emitting layer 35 includes one that uses light emission (fluorescence) from a singlet exciter, one that uses light emission (phosphorescence) from a triplet exciter, and one that uses light emission (fluorescence) from a singlet exciter. Those that include those that utilize and those that utilize light emission (phosphorescence) from triplet excitators, those that are formed by organic substances, those that are formed by organic substances and those that are formed by inorganic substances, high. A molecular material, a low molecular weight material, a material containing a high molecular weight material and a low molecular weight material, and the like can be used. However, the present invention is not limited to this, and a light emitting layer 35 using various known ones for EL elements can be used for the organic EL display device 30.

A desiccant (not shown) is placed in the space between the cathode electrode 36 and the sealing layer 37. This is because the light emitting layer 35 is sensitive to humidity. Moisture is absorbed by the desiccant to prevent deterioration of the light emitting layer 35.

The organic EL display device 30 of the present invention shown in FIG. 3B includes the circular polarizing plate 31, and has a light emitting layer on a substrate 32 on which a pixel electrode 34 is formed via an interlayer insulating film 33. 35 and the cathode electrode 36 are laminated. A sealing layer 37 is formed on the cathode electrode, and the circular polarizing plate 31 is arranged on the side opposite to the substrate 32. The light emitted from the light emitting layer 35 passes through the cathode electrode 36, the sealing layer 37, and the main circular polarizing plate 31.

Hereinafter, the present invention will be described in more detail with reference to Examples. Unless otherwise specified, "%" and "part" in the example are mass% and parts by mass.

Example 1
[Preparation of composition for forming a retardation layer]
The following components were mixed, and the obtained mixture was stirred at 80 ° C. for 1 hour to obtain a composition for forming a retardation layer.

Compound A1 and Compound A2 were synthesized by the method described in JP-A-2010-31223.
Compound A1 (80 parts):

Compound A2 (20 parts):

Polymerization initiator (6 parts):
2-Dimethylamino-2-benzyl-1- (4-morpholinophenyl) butane-1-one (Irgacure 369; manufactured by Ciba Specialty Chemicals)
Leveling agent (0.1 part): Polyacrylate compound (BYK-361N; BYK-Chemie solvent: mixed solvent of o-xylene (300 parts) and cyclopentanone (130 parts)

溶剤（９５部）：シクロペンタノン [Preparation of composition for forming a photoalignment film]
The following components were mixed, and the obtained mixture was stirred at 80 ° C. for 1 hour to obtain a composition for forming a photoalignment film.
Photo-oriented material (5 parts):

Solvent (95 parts): Cyclopentanone

化合物Ｂ２（化合物（Ｂ−７）；２５部）

二色性色素；
ビスアゾ化合物（１−１−１） ２．５部

ビスアゾ化合物（１−１−２） ２．５部

ビスアゾ化合物（１−４−１） ２．５部

重合開始剤；
２−ジメチルアミノ−２−ベンジル−１−（４−モルホリノフェニル）ブタン−１−オン（イルガキュア３６９；チバ スペシャルティケミカルズ社製） ６部
レベリング剤；
ポリアクリレート化合物（ＢＹＫ−３６１Ｎ；ＢＹＫ−Ｃｈｅｍｉｅ社製）
１．５部
溶剤；シクロペンタノン ２５０部 [Preparation of composition for forming a polarizing layer]
The following components were mixed, and the obtained mixture was stirred at 80 ° C. for 1 hour to obtain a composition for forming a polarizing layer. Compound B1 and Compound B2 were synthesized by the method described in Japanese Patent No. 4719156.
Compound B1 (Compound (B-6); 75 parts)

Compound B2 (Compound (B-7); 25 parts)

Dichroic pigment;
Bisazo compound (1-1-1) 2.5 parts

Bisazo compound (1-1-2) 2.5 parts

Bisazo compound (1-4-1) 2.5 parts

Polymerization initiator;
2-Dimethylamino-2-benzyl-1- (4-morpholinophenyl) butane-1-one (Irgacure 369; manufactured by Ciba Specialty Chemicals) 6-part leveling agent;
Polyacrylate compound (BYK-361N; manufactured by BYK-Chemie)
1.5 parts solvent; 250 parts cyclopentanone

[Measurement of phase transition temperature]
The obtained composition for forming a polarizing layer was applied onto glass and dried to prepare a sample for measurement. When the phase transition temperature was confirmed by observing the texture with a polarizing microscope, the phase transition to the nematic phase at 108 ° C and the phase transition to the smectic A phase at 101 ° C were 76 ° C after the temperature was raised to 140 ° C. The phase transition to the smectic B phase was confirmed in each.

[Preparation of composition for forming adhesive]
The following components were mixed in a nitrogen atmosphere at 55 ° C. to obtain an acrylic resin.
Butyl acrylate 70 parts Methyl acrylate 20 parts Acrylic acid 1.0 part Initiator: Azobisisobutyronitrile 0.2 part Solvent (80 parts): Ethyl acetate Furthermore, coronate L (trilenic isocyanate tri) 75% ethyl acetate solution of methylol propane adduct, number of isocyanate groups in one molecule: 3, 0.5 parts (manufactured by Nippon Polyurethane Industry Co., Ltd.), silane coupling agent X-12-981 (manufactured by Shinetsu Silicone Co., Ltd.) 0.5 parts were mixed, and finally ethyl acetate was added so that the total solid content concentration became 10% to prepare a composition for forming a pressure-sensitive adhesive. The obtained adhesive-forming composition was applied to the release-treated surface of the release-treated polyethylene terephthalate film (manufactured by Lintec Corporation) using an applicator so that the thickness after drying was 10 μm. The film (1) with an adhesive was obtained by drying at 100 ° C. for 1 minute.

[Manufacturing of circularly polarizing plate]
1. 1. Formation of Alignment Film for Polarizing Layer KC4UY (TAC film, manufactured by Konica Minolta Co., Ltd.), which is a cellulosic film, was used as the transparent base film. The composition for forming a photoalignment film was applied onto the film by a bar coating method, and dried by heating in a drying oven at 60 ° C. for 1 minute. The obtained dry film was subjected to polarized UV irradiation treatment to form a first alignment film. The polarized UV treatment was carried out using a UV irradiation device (SPOT CURE SP-7; manufactured by Ushio, Inc.) under the condition that the intensity measured at a wavelength of 365 nm was 100 mJ. Further, the polarization direction of the polarized UV was set to 0 ° with respect to the slow axis of the retardation layer.

2. 2. Formation of Polarizing Layer The composition for forming a polarizing layer was applied on the formed first alignment film by a bar coating method, heated and dried in a drying oven at 120 ° C. for 1 minute, and then cooled to room temperature. A polarizing layer was formed by irradiating the dry film with ultraviolet rays at an exposure of 1200 mJ / cm ² (365 nm standard) using a UV irradiation device (SPOT CURE SP-7; manufactured by Ushio, Inc.). The thickness of the obtained polarizing layer was measured with a laser microscope (OLS3000 manufactured by Olympus Corporation) and found to be 1.8 μm.

3. 3. Formation of Protective Layer On the formed polarizing layer, 50 parts of dipentaerythritol hexaacrylate (manufactured by Aronix M-403 Toa Synthetic Co., Ltd.), 50 parts of acrylate resin (manufactured by Evecryl 4858 Dycel UCB Co., Ltd.) and 2-methyl-1 [4- (Methylthio) phenyl] -2-Moliphorinopropan-1-one (Irgacure 907; manufactured by Ciba Specialty Chemicals) A solution prepared by dissolving 3 parts in 250 parts of isopropanol (composition for forming a protective layer). ) Was applied by the bar coating method and dried by heating in a drying oven at 50 ° C. for 1 minute. The obtained dry film was irradiated with ultraviolet rays at an exposure of 400 mJ / cm ² (365 nm standard) using a UV irradiation device (SPOT CURE SP-7; manufactured by Ushio, Inc.) on the polarizing layer. A protective layer was formed on the surface.

4. Formation of Alignment Film for Phase Difference Layer The composition for forming a photoalignment film was applied onto the formed protective layer by a bar coating method, and dried by heating in a drying oven at 60 ° C. for 1 minute. The obtained dry film was subjected to polarized UV irradiation treatment to form a second alignment film. The polarized UV treatment was carried out using a UV irradiation device (SPOT CURE SP-7; manufactured by Ushio, Inc.) under the condition that the intensity measured at a wavelength of 365 nm was 100 mJ. Further, the polarization direction of the polarized UV was set to 45 ° with respect to the absorption axis of the polarizing layer.

5. Formation of a retardation layer The composition for forming a retardation layer was applied on the formed second alignment film by a bar coating method, heated and dried in a drying oven at 120 ° C. for 1 minute, and then cooled to room temperature. A retardation layer is formed by irradiating the obtained dry film with ultraviolet rays having an exposure of 1000 mJ / cm ² (365 nm standard) using a UV irradiation device (SPOT CURE SP-7; manufactured by Ushio, Inc.). did. The thickness of the obtained retardation layer was measured with a laser microscope (OLS3000 manufactured by Olympus Corporation) and found to be 2.0 μm.

Thus, a broadband circular polarizing plate could be produced. The total thickness of the circularly polarizing plate was measured with a contact film thickness meter and found to be 45 μm.

[Evaluation of circularly polarizing plate]
1. 1. X-ray diffraction measurement The obtained polarizing layer was subjected to X-ray diffraction measurement by an X-ray diffractometer X'Pert PRO MPD (manufactured by Spectris Co., Ltd.). Using Cu as a target, X-rays generated under the conditions of an X-ray tube current of 40 mA and an X-ray tube voltage of 45 kV are rubbed in the rubbing direction through a fixed divergence slit 1/2 ° (in advance, the rubbing direction of the alignment film under the polarizing layer). The measurement was performed by scanning from 2θ = 0.01671 ° step in the scanning range of 2θ = 4.0 to 40.0 °. As a result, a sharp diffraction peak with a peak half width (FWHM) = about 0.29 ° was obtained near 2θ = 20.12 °. In addition, the same result was obtained when the measurement was performed by injecting X-rays from the rubbing vertical direction. The ordered period (d) obtained from the peak position was about 4.4Å, and it was found that a structure reflecting the higher-order smectic phase was formed.

2. 2. Measurement of reflectance In order to confirm the usefulness of the circular polarizing plate, the reflectance was measured as follows. A measurement sample was prepared by laminating the retardation layer of the produced circularly polarizing plate and the reflector (mirror-surfaced aluminum plate) with an adhesive.
Using a spectrophotometer (UV-3150 manufactured by Shimadzu Corporation), light in the wavelength range of 400 to 700 nm is incident on the measurement sample in 2 nm steps from 12 ° in the normal direction, and the reflectance of the reflected light. Was measured. When the reflectance is calculated assuming that the reflectance is 100% when only the reflector is placed and measured without attaching the circular polarizing plate, the reflectance of light having a wavelength in the range of 400 to 700 nm is about 1 to 10%. It was found that sufficient antireflection characteristics can be obtained over the entire visible light range.

Example 2
In the same manner as in Example 1, a first alignment film (polarization direction of polarized UV is 45 ° with respect to the long side of the substrate film) is formed on one surface of the transparent base film, and the light alignment film is formed. A retardation layer was formed in. After forming a protective layer on the retardation layer, a second alignment film (the polarization direction of the polarizing UV is 0 ° with respect to the long side of the base film) is formed, and a polarizing layer is further formed on the photoalignment film. It was formed to produce a circularly polarizing plate.

Similar to Example 1, the transparent base film of the circular polarizing plate and the reflecting plate were bonded together with an adhesive to measure the reflectance, and the reflectance of light having a wavelength in the range of 400 to 700 nm was measured. Is about 1 to 10%, and it was found that sufficient antireflection characteristics can be obtained over the entire visible light range.

Example 3
As the polymerizable liquid crystal compound B1, the compound (B-14) is used instead of the compound (B-6), and as the polymerizable liquid crystal compound B2, the compound (B-17) is used instead of the compound (B-7). A circularly polarizing plate was prepared by carrying out the same procedure as in Example 1 except for the above.

Similar to Example 1, when the retardation layer of the prepared circular polarizing plate and the reflecting plate were bonded together with an adhesive and the reflectance was measured, the reflectance of light having a wavelength in the range of 400 to 700 nm was found. It was about 1 to 10%, and it was found that sufficient antireflection characteristics could be obtained over the entire visible light range.

Comparative Example 1
As the retardation film, a 1/4 wave plate (Zeonoa film, Nippon Zeon Co., Ltd., in-plane retardation value Ro: 138 nm), which is a uniaxially stretched film of a cyclic olefin resin, was used, and the position was the same as in Example 1. A first alignment film (the polarization direction of the polarizing UV is 45 ° with respect to the slow axis of the retardation film) is formed on one surface of the retardation film, and a polarizing layer is further formed on the first alignment film. To prepare a circularly polarizing plate.

Similar to Example 1, when the prepared circular polarizing plate was attached to a reflecting plate using an adhesive and the reflectance was measured, the reflectance of light having a wavelength of 500 to 600 nm was good at about 1 to 10%. However, the reflectance of light having a wavelength of 400 to 500 nm and the reflectance of light having a wavelength of 600 to 700 nm are 10% or more, the reflected light exhibits a bluish purple color, and a sufficient antireflection function is provided. It turned out that I couldn't get it.

Comparative Example 2
As a polarizing plate, an iodine-PVA polarizing plate (manufactured by Sumikaran Sumitomo Chemical Co., Ltd., thickness 105 μm) was cut into small pieces of 100 × 100 mm so that the absorption axis was 0 °. The 1/2 wavelength plate used in Example 1 was cut into small pieces of 100 × 100 mm so that the slow axis was 15 °. The 1/4 wave plate used in Comparative Example 1 was cut into small pieces of 100 × 100 mm so that the slow axis was 15 °. Each of the cut out films was laminated with an acrylic pressure-sensitive adhesive (thickness 25 μm) so as to form a polarizing plate + 1/4 wavelength plate + 1/2 wavelength plate to prepare a circular polarizing plate.

Similar to Example 1, the prepared circularly polarizing plate was attached to a reflecting plate with an adhesive to measure the reflectance, and the reflectance of light having a wavelength in the range of 400 to 700 nm was 1 to 10%. It was found that sufficient antireflection characteristics could be obtained over the entire visible light range, but the total thickness of the circularly polarizing plate was measured by a contact type film thickness meter and found to be 240 μm, which is the circle of Example 1. It was about 5 times the total thickness of the polarizing plate.

Example 4
A circularly polarizing plate was produced by the same method as in Example 1 except that a polyethylene terephthalate film was used instead of KC4UY (TAC film, manufactured by Konica Minolta Co., Ltd.), which is a cellulosic film, as a base material. A film (1) with an adhesive was bonded onto the retardation layer of the circularly polarizing plate to obtain a circularly polarizing plate having an adhesive layer. This sample is cut to a size of 40 mm × 40 mm, the film of the adhesive film attached is peeled off, it is pressure-bonded to a reflector (mirror surface aluminum plate), and the substrate is slowly removed to form a circularly polarizing film. I got a reflector with attached. The thickness of the circularly polarizing film including the first alignment film, the polarizing layer, the protective layer, the second alignment film, the retardation layer and the pressure-sensitive adhesive layer was 14.7 μm.
The peel strength (F1) between the substrate and the first alignment film is the peel strength between the first alignment film and the polarizing layer (F2), the peel strength between the second alignment film and the retardation layer (F3), and Since the peel strength (F4) between the retardation layer and the pressure-sensitive adhesive layer was lower, peeling occurred between the base material and the first alignment film, and the base material could be removed.

When the reflectance was measured in the same manner as in Example 1, the reflectance of light having a wavelength in the range of 400 to 700 nm was about 1 to 10%, and sufficient antireflection characteristics could be obtained over the entire visible light range. I found out. Since this antireflection principle is the same as that of external light reflection by the metal electrode of the organic EL display, it is also preferably used for the organic EL display.

The circularly polarizing plate of the present invention has sufficient performance as a broadband circularly polarizing plate, its thickness can satisfy the thinning of the display device, and its manufacturing process is simple. Further, the display device provided with the circularly polarizing plate of the present invention can be made thinner.

1 Circularly polarizing plate 2 Base material 3 Substituent layer 4 Polarizing layer 5 Bicolor dye 10 Liquid crystal display device 11a, 11b This circularly polarizing plate 12a, 12b Substrate 13 Color filter 14 Transparent electrode 15 Liquid crystal layer 16 Thin film transistor 17 Back Light unit 18 Black matrix 19 Thin film transistor 20 Pixel electrode 21 Spacer 30 Organic EL display device 31 Circularly polarizing plate 32 Substrate 33 Interlayer insulating film 34 Pixel electrode 35 Light emitting layer 36 Cathode electrode 37 Sealing layer 38 Thin film transistor 39 Rib

Claims (21)

It has a base material, a retardation layer, and a polarizing layer, and the dichroism Δn (λ) of the retardation layer with respect to light having a wavelength of λ nm satisfies the equations (1) and (2), and the retardation layer and the polarizing layer. A circular polarizing plate characterized in that both layers are coating layers, the total thickness of the retardation layer and the polarizing layer is 10 μm or less, and the polarizing layer contains a dichroic dye.
Δn (450) / Δn (550) ≦ 1.00 (1)
1.00 ≦ Δn (650) / Δn (550) (2) The circularly polarizing plate according to claim 1, which is formed by polymerizing a polymerizable liquid crystal having one or more retardation layers. The circular polarizing plate according to claim 1 or 2, wherein the polarizing layer is formed by polymerizing one or more polymerizable liquid crystals. The circularly polarizing plate according to claim 2 or 3, wherein the polymerizable liquid crystal is polymerized by light irradiation. The circular polarizing plate according to any one of claims 1 to 4, wherein the polarizing layer is a polarizing layer from which a Bragg peak can be obtained in X-ray diffraction measurement. The circular polarizing plate according to any one of claims 1 to 5, wherein the thickness of the retardation layer and the polarizing layer is 5 μm or less, respectively. The circular polarizing plate according to any one of claims 1 to 6, wherein the retardation layer, the polarizing layer, or both are formed on the alignment film. The circular polarizing plate according to claim 7, wherein the alignment film is an alignment film in which an orientation regulating force is generated by light irradiation. The circular polarizing plate according to claim 7 or 8, wherein the alignment film has a thickness of 500 nm or less. Claims 1 to 9 in which a retardation layer is formed on a substrate with or without an alignment film, and a polarizing layer is formed on the retardation layer with or without an alignment film. The circular polarizing plate according to any one. Any of claims 1 to 9, wherein a polarizing layer is formed on the substrate with or without an alignment film, and a retardation layer is formed on the polarizing layer with or without an alignment film. Circularly polarizing plate described in Crab. The circular polarizing plate according to claim 10 or 11, wherein a protective layer is provided between the polarizing layer and the retardation layer. Claim that a polarizing layer is formed on one surface of the base material with or without an alignment film, and a retardation layer is formed on the other surface of the base material with or without an alignment film. The circular polarizing plate according to any one of 1 to 9. The circular polarizing plate according to any one of claims 1 to 13, further comprising an adhesive layer on the surface of the retardation layer or the polarizing layer. The circular polarizing plate according to claim 14, further comprising a base material, a first alignment film, a polarizing layer, a second alignment film, a retardation layer, and an adhesive layer in this order. The peel strength (F1) between the base material and the first alignment film is the peel strength between the first alignment film and the polarizing layer (F2), the peel strength between the second alignment film and the retardation layer (F3), and The circularly polarizing plate according to claim 15, which is lower than the peel strength (F4) between the retardation layer and the pressure-sensitive adhesive layer. A display device including the circularly polarizing plate according to any one of claims 1 to 16 and a display element. The circularly polarizing film from which the base material is removed from the circularly polarizing plate according to any one of claims 14 to 16 is bonded to the display surface of the display element via the pressure-sensitive adhesive layer of the circularly polarizing film. Display device. The display device according to claim 18, wherein the thickness of the circularly polarizing film is 5 μm or more and 15 μm or less. The display device according to any one of claims 17 to 19, wherein the display element is a liquid crystal cell, an organic electroluminescence element, or a touch panel. With a circularly polarizing film, the circularly polarizing plate according to any one of claims 14 to 16 is attached to a display surface of a display element via an adhesive layer of the circularly polarizing plate, and a substrate is removed from the circularly polarizing plate. How to manufacture a display device.

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