WO2018016360A1

WO2018016360A1 - Elliptical polarizing plate

Info

Publication number: WO2018016360A1
Application number: PCT/JP2017/025074
Authority: WO
Inventors: 辰昌葛西; 伸行幡中
Original assignee: 住友化学株式会社
Priority date: 2016-07-21
Filing date: 2017-07-10
Publication date: 2018-01-25
Also published as: CN109477925B; JP7166049B2; KR102652054B1; TWI723200B; CN115390178A; KR20220149628A; JP2018022152A; KR20190027826A; KR102481313B1; CN109477925A; TW201807440A

Abstract

[Problem] To provide an elliptical polarizing plate in which alignment defects or optical axis deviation is suppressed. [Solution] In this elliptical polarizing plate, an alignment layer A, a phase difference layer, an alignment layer B, and a polarization layer are provided in this order on a transparent substrate, the optical axes of the polarization layer and the phase difference layer are essentially non-parallel, the phase difference layer is a film configured from a polymer of a polymerizable liquid crystal compound, the alignment layer B is a film having a thickness of 80 nm to 800 nm, and the polarization layer is obtained by aligning a dichroic pigment in a film configured from a polymer of a polymerizable liquid crystal compound.

Description

Elliptical polarizing plate

The present invention relates to an elliptically polarizing plate. The present invention also relates to a display device including an elliptically polarizing plate and a method for manufacturing the elliptically polarizing plate.

For flat panel display (FPD), optical films such as polarizing plates and retardation plates are used. As such a polarizing plate, a polarizing plate comprising a polarizing layer in which a dichroic dye such as iodine is oriented and adsorbed on a polyvinyl alcohol resin film and a protective film is widely used. As a retardation plate, a retardation plate obtained by stretching a cycloolefin resin film, a polycarbonate resin film, or a triacetyl cellulose resin film is widely known. Along with the recent reduction in thickness, a thin film polarizing plate and a retardation plate produced by applying a composition containing a polymerizable liquid crystal compound to a substrate have been developed. For example, Patent Document 1 discloses a retardation film that exhibits reverse wavelength dispersion, and Patent Document 2 discloses a polarizing layer that exhibits high polarization performance. In order to further reduce the thickness, for example, Patent Document 3 discloses a technique for forming a polarizing layer and a retardation film via a protective layer. These polarizing layers and retardation layers are often laminated together and used as an elliptically polarizing plate.

Special table 2010-537955 Special table 2013-101328 gazette Special table 2014-63143 gazette

However, the conventional elliptically polarizing plate obtained in this way has a problem that an alignment defect or an optical axis shift occurs in the polarizing layer. The alignment defect of the polarizing layer impairs the function as an elliptically polarizing plate at the defect portion. Further, the optical axis shift impairs the function as an elliptically polarizing plate.
As a result of studies by the present inventors, it has been found that a polarizing plate in which alignment defects and optical axis misalignment are suppressed can be provided.
An object of this invention is to provide the elliptically polarizing plate by which the orientation defect and optical axis shift of the polarizing layer were suppressed.

That is, the present invention provides the following [1] to [13].
[1] An elliptically polarizing plate in which an alignment layer A, a retardation layer, an alignment layer B and a polarizing layer are provided in this order on a transparent substrate,
The optical axis of the polarizing layer and the retardation layer is not substantially parallel,
The retardation layer is a film composed of a polymer of a polymerizable liquid crystal compound,
The alignment layer B is a film having a thickness of 80 nm to 800 nm,
An elliptically polarizing plate in which the polarizing layer is a film in which a dichroic dye is dispersed and oriented in a film composed of a polymer of a polymerizable liquid crystal compound.
[2] The elliptically polarizing plate according to [1], wherein the transparent base material, the alignment layer A, the retardation layer, the alignment layer B, and the polarizing layer all have an average refractive index in the range of 1.4 to 1.7.
[3] The elliptically polarizing plate according to [1] or [2], wherein the difference in refractive index between adjacent layers is 0.2 or less.
[4] The elliptically polarizing plate according to any one of [1] to [3], wherein an angle formed by an optical axis of the polarizing layer and the retardation layer is in a range of 40 ° to 50 °.
[5] The elliptically polarizing plate according to any one of [1] to [4], wherein the alignment layer A and the alignment layer B are both photo-alignment films.
[6] The elliptically polarizing plate according to any one of [1] to [5], wherein the alignment layer A and the alignment layer B are photo-alignment films containing a cinnamoyl group.
[7] The elliptically polarizing plate according to any one of [1] to [6], wherein the alignment layer A and the alignment layer B are photo-alignment films containing a resin having a weight average molecular weight of 20000 to 50000.
[8] The elliptically polarizing plate according to any one of [1] to [7], wherein the polarizing layer is a film composed of a polymer in a smectic liquid crystal state.
[9] The elliptically polarizing plate according to any one of [1] to [8], wherein the dichroic dye is an azo dye.
[10] The elliptically polarizing plate according to any one of [1] to [9], wherein the retardation layer satisfies all of the following formulas.
100 nm <Re (550) <160 nm (1)
Re (450) / Re (550) ≦ 1.0 (2)
1.00 ≦ Re (650) / Re (550) (3)
(Re (450), Re (550), and Re (650) represent in-plane retardation at wavelengths of 450 nm, 550 nm, and 650 nm, respectively)
[11] A liquid crystal display device comprising the elliptically polarizing plate according to any one of [1] to [10].
[12] An organic EL display device comprising the elliptically polarizing plate according to any one of [1] to [11].
[13] On the transparent substrate,
Applying a composition containing an alignment material A and a solvent, and irradiating polarized UV after drying to form an alignment layer A;
Step (2) of forming a retardation layer by applying a composition containing a polymerizable liquid crystal compound, a polymerization initiator and a solvent on the alignment layer A, drying and then polymerizing in a liquid crystal state by UV irradiation. When,
Applying a composition containing an alignment material B and a solvent, irradiating polarized UV after drying to form an alignment layer B;
On the alignment layer B, a composition containing a polymerizable liquid crystal compound, a dichroic dye, a polymerization initiator and a solvent is applied, and after drying, a UV light is irradiated and polymerized in a liquid crystal state to form a polarizing layer. And a manufacturing method of an elliptically polarizing plate having step (4).

According to the present invention, it is possible to provide an elliptically polarizing plate in which the optical axis misalignment between the retardation layer and the polarizing layer and the occurrence of alignment defects are suppressed.

Hereinafter, embodiments of the present invention will be described in detail. Note that the scope of the present invention is not limited to the embodiment described here, and various modifications can be made without departing from the spirit of the present invention.

The elliptically polarizing plate of the present invention is an elliptically polarizing plate in which an alignment layer A, a retardation layer, an alignment layer B, and a polarizing layer are provided in this order on a transparent substrate.

[Transparent substrate]
As a transparent base material, a glass base material and a film base material are mentioned, A film base material is preferable. A long roll-like film is more preferable at the point which can manufacture continuously.
Examples of the resin constituting the film substrate include polyolefins such as polyethylene, polypropylene, norbornene polymers, cyclic olefin resins, polyvinyl alcohol, polyethylene terephthalate, polymethacrylates, polyacrylates, triacetylcellulose, and diacetylcellulose. And cellulose esters such as cellulose acetate propionate; polyethylene naphthalate; polycarbonate; polysulfone; polyethersulfone; polyetherketone; polyphenylene sulfide and polyphenylene oxide;
Examples of the commercially available cellulose ester base material include “Fujitac Film” (manufactured by Fuji Photo Film Co., Ltd.); “KC8UX2M”, “KC8UY” and “KC4UY” (manufactured by Konica Minolta Opto Co., Ltd.).
Commercially available cyclic olefin-based resins include “Topas” (registered trademark) (manufactured by Ticona (Germany)), “Arton” (registered trademark) (manufactured by JSR Corporation), “ZEONOR” (registered trademark), “ZEONEX” (registered trademark) (manufactured by Nippon Zeon Co., Ltd.) and “Apel” (registered trademark) (manufactured by Mitsui Chemicals, Inc.) can be mentioned. Such a cyclic olefin-based resin can be formed into a substrate by forming a film by a known means such as a solvent casting method or a melt extrusion method. Commercially available cyclic olefin resin base materials can also be used. Commercially available cyclic olefin-based resin base materials include “Essina” (registered trademark), “SCA40” (registered trademark) (manufactured by Sekisui Chemical Co., Ltd.), “Zeonor Film” (registered trademark) (manufactured by Optes Corporation). ) And “Arton Film” (registered trademark) (manufactured by JSR Corporation).
The thickness of the base material is preferably thin in view of easy practical handling, but if it is too thin, the strength tends to decrease and the workability tends to be poor. The thickness of the substrate is usually 5 μm to 300 μm, preferably 20 μm to 200 μm.

[Alignment layer A (alignment film for forming retardation layer)]
An alignment layer A is first formed on the transparent substrate. The alignment layer A (or alignment film A) is a layer having an alignment regulating force that aligns the polymerizable liquid crystal compound used for forming the retardation layer in a desired direction.
As the alignment layer A, those having solvent resistance that does not dissolve due to application of a liquid crystal compound described later, and heat resistance in heat treatment for removing the solvent and aligning the polymerizable liquid crystal compound described below are preferable. Examples of the alignment film include a rubbing alignment film, a photo-alignment film, and a groove alignment film having a concavo-convex pattern and a plurality of grooves on the surface. When applied to a long roll-shaped film, a photo-alignment film in which an alignment regulating force is induced by irradiation with polarized light is preferable in that the alignment direction can be easily controlled.
Such an alignment film facilitates the alignment of the polymerizable liquid crystal compound. In addition, various orientations such as horizontal orientation, hybrid orientation, and tilt orientation can be controlled depending on the type of orientation film, rubbing conditions, and light irradiation conditions.
As the alignment layer A used for forming the retardation layer, the alignment film described in the alignment layer B described later can be used. The alignment layer B may be the same as or different from the alignment layer A.

The thickness of the alignment layer A is usually in the range of 10 to 10000 nm (0.01 μm to 10 μm), preferably in the range of 80 to 800 nm (0.08 μm to 0.8 μm), more preferably 100 to 500 nm ( 0.1 μm to 0.5 μm). By forming the alignment layer A within this film thickness range, alignment defects can be suppressed.
[Phase difference layer]

The elliptically polarizing plate of the present invention has a retardation layer next to the alignment layer A. The retardation layer is formed by applying a composition containing a polymerizable liquid crystal compound (hereinafter also referred to as a retardation layer forming composition) onto the alignment layer A to form an application layer, and the polymerizable liquid crystal compound is formed in the application layer. It is preferable from the viewpoint that the layer can be made thin and the wavelength dispersion characteristic can be arbitrarily designed. A composition used for forming a retardation layer (hereinafter referred to as a retardation layer forming composition) is a solvent, a photopolymerization initiator, a photosensitizer, a polymerization inhibitor, a leveling agent, and an adhesion improver. And the like.

The retardation layer in the elliptically polarizing plate of the present invention is usually a polymerization contained in the optical anisotropic layer forming composition by applying the retardation layer forming composition to the alignment layer A formed on the substrate. It is formed by polymerizing a conductive liquid crystal compound. The retardation layer is usually a film having a thickness of 5 μm or less cured with the polymerizable liquid crystal compound aligned, and preferably cured with the polymerizable liquid crystal compound aligned in the horizontal direction with respect to the substrate surface. This is a cured liquid crystal film.

The retardation layer cured in a state where the polymerizable liquid crystal compound is aligned in the horizontal direction with respect to the substrate surface has an in-plane retardation R (λ) with respect to light having a wavelength of λ nm as shown in the following formula (1). It is preferable to satisfy the optical characteristics, and it is more preferable to satisfy the optical characteristics represented by the following formula (1), the following formula (2), and the following formula (3).
100 nm <Re (550) <160 nm (1)
(In the formula, Re (550) represents an in-plane retardation value (in-plane retardation) for light having a wavelength of 550 nm.)
Re (450) / Re (550) ≦ 1.0 (2)
1.00 ≦ Re (650) / Re (550) (3)
(Where Re (450) is the in-plane retardation value for light having a wavelength of 450 nm, Re (550) is the in-plane retardation value for light having a wavelength of 550 nm, and Re (650) is the in-plane retardation value for light having a wavelength of 650 nm. Represents the phase difference value.)
When “Re (450) / Re (550)” of the retardation layer exceeds 1.0, light leakage on the short wavelength side in the elliptically polarizing plate provided with the retardation layer becomes large, so that it is 1.0 or less. Is more preferable, 0.95 or less, still more preferably 0.92 or less.

The in-plane retardation value of the retardation layer can be adjusted by the thickness of the retardation layer. Since the in-plane retardation value is determined by the following equation (4), Δn (λ) and film thickness d may be adjusted to obtain a desired in-plane retardation value (Re (λ)). . The thickness of the retardation layer is preferably 0.5 μm to 5 μm, more preferably 1 μm to 3 μm. The thickness of the retardation layer can be measured with an interference film thickness meter, a laser microscope or a stylus thickness meter. Δn (λ) depends on the molecular structure of the polymerizable liquid crystal compound described later.
Re (λ) = d × Δn (λ) (4)
(In the formula, Re (λ) represents the in-plane retardation value at the wavelength λnm, d represents the film thickness, and Δn (λ) represents the birefringence at the wavelength λnm.)

[Polymerizable liquid crystal compound for retardation layer formation]
The polymerizable liquid crystal compound is a liquid crystal compound having a polymerizable functional group, particularly a photopolymerizable functional group. The photopolymerizable functional group refers to a group that can participate in a polymerization reaction by an active radical or an acid generated from a photopolymerization initiator. Examples of the photopolymerizable functional group include a vinyl group, vinyloxy group, 1-chlorovinyl group, isopropenyl group, 4-vinylphenyl group, acryloyloxy group, methacryloyloxy group, oxiranyl group, and oxetanyl group. Among them, acryloyloxy group, methacryloyloxy group, vinyloxy group, oxiranyl group and oxetanyl group are preferable, and acryloyloxy group is more preferable. The thermic liquid crystal may be either a thermotropic liquid crystal or a lyotropic liquid crystal, but the thermotropic liquid crystal is preferred in terms of enabling precise film thickness control. Further, the phase order structure in the thermotropic liquid crystal may be a nematic phase structure or a smectic phase structure.

In the present invention, the polymerizable liquid crystal compound forming the retardation layer is particularly preferably a compound having the structure of the following formula (I) from the viewpoint of exhibiting the above-described reverse wavelength dispersion.

In formula (I), Ar represents a divalent aromatic group, and the divalent aromatic group contains at least one of a nitrogen atom, an oxygen atom and a sulfur atom.
G ¹ and G ² each independently represents a divalent aromatic group or a divalent alicyclic hydrocarbon group. Here, the hydrogen atom contained in the divalent aromatic group or divalent alicyclic hydrocarbon group is a halogen atom, an alkyl group having 1 to 4 carbon atoms, a fluoroalkyl group having 1 to 4 carbon atoms, carbon The carbon atom constituting the divalent aromatic group or divalent alicyclic hydrocarbon group which may be substituted with an alkoxy group, cyano group or nitro group of 1 to 4 is an oxygen atom or a sulfur atom Alternatively, it may be substituted with a nitrogen atom.
L ¹ , L ² , B ¹ and B ² are each independently a single bond or a divalent linking group.
k and l each independently represent an integer of 0 to 3, and satisfy the relationship of 1 ≦ k + 1. Here, when 2 ≦ k + 1, B ¹ and B ² , G ¹ and G ² may be the same or different from each other.
E ¹ and E ² each independently represents an alkanediyl group having 1 to 17 carbon atoms, wherein a hydrogen atom contained in the alkanediyl group may be substituted with a halogen atom, The —CH ₂ — contained may be substituted with —O— or —Si—.
P ¹ and P ² each independently represent a polymerizable group or a hydrogen atom, and at least one is a polymerizable group.

G ¹ and G ² are each independently preferably a 1,4-phenyl group which may be substituted with at least one substituent selected from the group consisting of a halogen atom and an alkyl group having 1 to 4 carbon atoms, 1,4-cyclohexyl group optionally substituted with at least one substituent selected from the group consisting of a halogen atom and an alkyl group having 1 to 4 carbon atoms, more preferably 1,4 substituted with a methyl group A phenyl group, an unsubstituted 1,4-phenyl group, or an unsubstituted 1,4-trans-cyclohexyl group, particularly preferably an unsubstituted 1,4-phenyl group or an unsubstituted 1,4- a trans-cyclohexyl group;
In addition, at least one of a plurality of G ¹ and G ² is preferably a divalent alicyclic hydrocarbon group, and at least one of G ¹ and G ² bonded to L ¹ or L ² More preferably, it is a divalent alicyclic hydrocarbon group.

L ¹ and L ² are each independently preferably a single bond, —O—, —CH ₂ CH ₂ —, —CH ₂ O—, —COO—, —OCO—, —N═N—, —CR ^a = CR ^b- , or -C≡C-. Here, R ^a and R ^b represent an alkyl group having 1 to 4 carbon atoms or a hydrogen atom. L ¹ and L ² are each independently more preferably a single bond, —O—, —CH ₂ CH ₂ —, —COO—, or —OCO—.

B ¹ and B ² are each independently preferably a single bond, —O—, —S—, —CH ₂ O—, —COO—, or —OCO—, and more preferably a single bond, —O— -, -COO-, or -OCO-.

K and l are preferably in the range of 2 ≦ k + l ≦ 6 from the viewpoint of expression of inverse wavelength dispersion, preferably k + l = 4, and more preferably k = 2 and l = 2. It is preferable that k = 2 and l = 2 because a symmetrical structure is obtained.

E ¹ and E ² are each independently preferably an alkanediyl group having 1 to 17 carbon atoms, and more preferably an alkanediyl group having 4 to 12 carbon atoms.

Examples of the polymerizable group represented by P ¹ or P ² include epoxy group, vinyl group, vinyloxy group, 1-chlorovinyl group, isopropenyl group, 4-vinylphenyl group, acryloyloxy group, methacryloyloxy group, and oxiranyl group. And an oxetanyl group.
Among them, acryloyloxy group, methacryloyloxy group, vinyloxy group, oxiranyl group and oxetanyl group are preferable, and acryloyloxy group is more preferable.

Ar preferably has an aromatic heterocycle. Examples of the aromatic heterocycle include a furan ring, a benzofuran ring, a pyrrole ring, a thiophene ring, a pyridine ring, a thiazole ring, a benzothiazole ring, a thienothiazole ring, an oxazole ring, a benzoxazole ring, and a phenanthroline ring. . Of these, a thiazole ring, a benzothiazole ring, or a benzofuran ring is preferable, and a benzothiazole group is more preferable.
In addition, when Ar includes a nitrogen atom, the nitrogen atom preferably has π electrons.

Wherein (I), 2-valent of [pi Total N _[pi electrons contained in the aromatic group preferably 10 or more represented by Ar, more preferably 14 or more, further preferably 18 or more. Moreover, Preferably it is 30 or less, More preferably, it is 26 or less, More preferably, it is 24 or less.

Examples of the aromatic group represented by Ar include the following groups.

In formulas (Ar-1) to (Ar-20), * represents a linking part, and Z ⁰ , Z ¹ and Z ² are each independently a hydrogen atom, a halogen atom, or an alkyl having 1 to 12 carbon atoms. Group, cyano group, nitro group, alkylsulfinyl group having 1 to 12 carbon atoms, alkylsulfonyl group having 1 to 12 carbon atoms, carboxyl group, fluoroalkyl group having 1 to 12 carbon atoms, alkoxy group having 1 to 6 carbon atoms, An alkylthio group having 1 to 12 carbon atoms, an N-alkylamino group having 1 to 12 carbon atoms, an N, N-dialkylamino group having 2 to 12 carbon atoms, an N-alkylsulfamoyl group having 1 to 12 carbon atoms, or carbon This represents an N, N-dialkylsulfamoyl group of formula 2 to 12.

Q ¹ , Q ² and Q ³ each independently represents —CR ² ′ R ³ ′ —, —S—, —NH—, —NR ² ′ —, —CO— or —O—, and R ² ′ And R ³ ′ each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

Y ¹ , Y ² and Y ³ each independently represents an optionally substituted aromatic hydrocarbon group or aromatic heterocyclic group.

W ¹ and W ² each independently represents a hydrogen atom, a cyano group, a methyl group or a halogen atom, and m represents an integer of 0 to 6.

Examples of the aromatic hydrocarbon group in Y ¹ , Y ² and Y ³ include aromatic hydrocarbon groups having 6 to 20 carbon atoms such as a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group, and a biphenyl group. A naphthyl group is preferred, and a phenyl group is more preferred. The aromatic heterocyclic group has 4 to 20 carbon atoms and contains at least one hetero atom such as a nitrogen atom such as a furyl group, a pyrrolyl group, a thienyl group, a pyridinyl group, a thiazolyl group, or a benzothiazolyl group, an oxygen atom, or a sulfur atom. An aromatic heterocyclic group is mentioned, and a furyl group, a thienyl group, a pyridinyl group, a thiazolyl group, and a benzothiazolyl group are preferable.

Y ¹ , Y ² and Y ³ may each independently be an optionally substituted polycyclic aromatic hydrocarbon group or polycyclic aromatic heterocyclic group. The polycyclic aromatic hydrocarbon group refers to a condensed polycyclic aromatic hydrocarbon group or a group derived from an aggregate of aromatic rings. The polycyclic aromatic heterocyclic group refers to a condensed polycyclic aromatic heterocyclic group or a group derived from an aromatic ring assembly.

Z ⁰ , Z ¹ and Z ² are each independently preferably a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cyano group, a nitro group, or an alkoxy group having 1 to 12 carbon atoms. ⁰ is more preferably a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or a cyano group, and Z ¹ and Z ² are more preferably a hydrogen atom, a fluorine atom, a chlorine atom, a methyl group, or a cyano group.

Q ¹ , Q ² and Q ³ are preferably —NH—, —S—, —NR ² ′ — and —O—, and R ² ′ is preferably a hydrogen atom. Of these, —S—, —O—, and —NH— are particularly preferable.

Of the formulas (Ar-1) to (Ar-20), the formulas (Ar-6) and (Ar-7) are preferable from the viewpoint of molecular stability.
In formulas (Ar-14) to (Ar-20), Y ¹ may form an aromatic heterocyclic group together with the nitrogen atom to which it is bonded and Z ⁰ . Examples thereof include a pyrrole ring, an imidazole ring, a pyrroline ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, an indole ring, a quinoline ring, an isoquinoline ring, a purine ring, and a pyrrolidine ring. This aromatic heterocyclic group may have a substituent. Y ¹ may be the above-described optionally substituted polycyclic aromatic hydrocarbon group or polycyclic aromatic heterocyclic group together with the nitrogen atom to which it is bonded and Z ⁰ .

The total content of the polymerizable liquid crystal compound in the solid content of 100 parts by mass of the retardation layer forming composition is usually 70 parts by mass to 99.5 parts by mass, preferably 80 parts by mass to 99 parts by mass. Part, more preferably 80 parts by weight to 94 parts by weight. If the total content is within the above range, the orientation of the obtained retardation layer tends to be high. Here, solid content means the total amount of the component remove | excluding the solvent from the composition.

[Alignment layer B (alignment film for forming polarizing layer)]
The elliptically polarizing plate of the present invention has an alignment layer B next to the retardation layer. The alignment layer B is an alignment film for forming a polarizing layer.
The alignment layer B has a solvent resistance that does not dissolve due to application of a composition for forming a polarizing layer, which will be described later, and has heat resistance in heat treatment for removing the solvent and aligning a polymerizable liquid crystal compound, which will be described later. Those are preferred. Examples of the alignment film include a rubbing alignment film, a photo-alignment film, and a groove alignment film having a concavo-convex pattern and a plurality of grooves on the surface. When applied to a long roll-shaped film, a photo-alignment film in which an alignment regulating force is induced by irradiation with polarized light is preferable in that the alignment direction can be easily controlled.
Such an alignment film facilitates the alignment of the polymerizable liquid crystal compound. In addition, various orientations such as horizontal orientation, hybrid orientation, and tilt orientation can be controlled depending on the type of orientation film, rubbing conditions, and light irradiation conditions.

The thickness of the alignment layer B is in the range of 80 to 800 nm (0.08 μm to 0.8 μm), preferably in the range of 100 to 500 nm (0.1 μm to 0.5 μm), and more preferably 150 nm (0 .15 μm) or more. When the film thickness is smaller than this range, the optical axis of the polarizing layer next to the alignment layer B deviates from a desired value due to the influence of the layer formed immediately below the alignment layer, that is, the retardation layer. There is a case. On the other hand, when the film thickness is larger than this range, the alignment regulating force may be reduced and an alignment defect may occur in the polarizing layer.

Examples of the alignment polymer used for the rubbing alignment film include polyamides and gelatins having amide bonds, polyimides having imide bonds and polyamic acids, polyvinyl alcohols, alkyl-modified polyvinyl alcohols, polyacrylamides, polyacrylamides, and hydrolysates thereof. Examples include oxazole, polyethyleneimine, polystyrene, polyvinyl pyrrolidone, polyacrylic acid and polyacrylic acid esters. Among these, polyvinyl alcohol is preferable. Two or more kinds of orientation polymers may be combined.

A rubbing alignment film is generally formed by applying a composition in which an orientation polymer is dissolved in a solvent to a substrate, removing the solvent to form a coating film, and rubbing the coating film to impart alignment regulating force. Can do.

The concentration of the orienting polymer in the orienting polymer composition may be in a range where the orienting polymer is completely dissolved in the solvent. The content of the orientation polymer with respect to the orientation polymer composition is preferably 0.1 to 20% by mass, more preferably 0.1 to 10% by mass.

Alignment polymer composition can be obtained from the market. Examples of the commercially available oriented polymer composition include Sanever (registered trademark, manufactured by Nissan Chemical Industries, Ltd.), Optmer (registered trademark, manufactured by JSR).

Examples of the method for applying the orientation polymer composition include the same method as the method for applying the composition for forming an optically anisotropic layer described later. 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.

Examples of the rubbing treatment include a method in which a rubbing cloth is wound and the coating film is brought into contact with a rotating rubbing roll. If masking is performed when the rubbing treatment is performed, a plurality of regions (patterns) having different orientation directions can be formed in the alignment film.

For the photo-alignment film, a composition for forming a photo-alignment film usually containing a polymer or monomer having a photoreactive group and a solvent is applied onto a substrate or the like, and after removing the solvent, polarized light (preferably polarized UV) It is obtained by irradiating. The photo-alignment film can arbitrarily control the direction of the alignment regulating force by selecting the polarization direction of the polarized light to be irradiated.

The photoreactive group refers to a group that generates alignment ability when irradiated with light. Specific examples include groups that are involved in photoreactions that are the origin of alignment ability, such as alignment-induced reactions, isomerization reactions, photodimerization reactions, photocrosslinking reactions, or photodecomposition reactions of molecules generated by light irradiation. 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 nitrogen-nitrogen. 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 preferred.

Examples of the photoreactive group having a C═C bond include a vinyl group, a polyene group, a stilbene group, a stilbazole group, a stilbazolium group, a chalcone group, and a cinnamoyl group. Examples of the photoreactive group having a C═N bond include groups 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 a substituent such as an alkyl group, an alkoxy group, an aryl group, an allyloxy group, a cyano group, an alkoxycarbonyl group, a hydroxyl group, a sulfonic acid group, and a halogenated alkyl group.

A group that participates in the photodimerization reaction or photocrosslinking reaction is preferable in terms of excellent orientation. Among them, a photoreactive group involved in the photodimerization reaction is preferable, and a cinnamoyl group is preferable in that a photoalignment film having a relatively small amount of polarized light irradiation necessary for alignment and having excellent thermal stability and stability over time can be easily obtained. And chalcone groups are preferred. As the polymer having a photoreactive group, a polymer having a cinnamoyl group in which a terminal portion of the polymer side chain has a cinnamic acid structure or a cinnamic acid ester structure is particularly preferable.

The content of the polymer or monomer having a photoreactive group in the composition for forming a photoalignment film can be adjusted by the kind of the polymer or monomer and the thickness of the target photoalignment film, and is at least 0.2% by mass or more. The range is preferably 0.3 to 10% by mass.

Examples of the method for applying the composition for forming a photo-alignment film include the same methods as those for applying the composition for forming an optically anisotropic layer described later. Examples of the method for removing the solvent from the applied composition for forming a photo-alignment film include the same method as the method for removing the solvent from the oriented polymer composition.

In order to irradiate polarized light, the composition for forming a photo-alignment film applied on a substrate or the like is directly irradiated with polarized light on a solvent-removed composition. May be used such that the polarized light is transmitted and irradiated. The polarized light is preferably substantially parallel light. The wavelength of the polarized light to be irradiated should be in a wavelength range where the photoreactive group of the polymer or monomer having the photoreactive group can absorb light energy. Specifically, UV (ultraviolet light) having a wavelength in the range of 250 nm to 400 nm is particularly preferable. Examples of the light source for irradiating the polarized light include xenon lamps, high-pressure mercury lamps, ultra-high pressure mercury lamps, metal halide lamps, ultraviolet lasers such as KrF and ArF, and the like. Among these, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, and a metal halide lamp are preferable because of high emission intensity of ultraviolet rays having a wavelength of 313 nm.
By irradiating light from the light source through an appropriate polarizing element, polarized UV light can be irradiated. Examples of the polarizing element include polarizing prisms such as polarizing filters, Glan Thompson, and Grand Taylor, and wire grids. Among these, a wire grid type polarizing element is preferable from the viewpoint of an increase in area and resistance to heat.

Note that a plurality of regions (patterns) having different liquid crystal alignment directions can be formed by performing masking when performing rubbing or polarized light irradiation.

The groove alignment film is a film having a concavo-convex pattern or a plurality of grooves (grooves) on the film surface. When a polymerizable liquid crystal compound is applied to a film having a plurality of linear grooves arranged at equal intervals, liquid crystal molecules are aligned in a direction along the groove.
As a method for obtaining a groove alignment film, a method of forming a concavo-convex pattern by performing development and rinsing after exposure through an exposure mask having a pattern-shaped slit on the photosensitive polyimide film surface, a plate having grooves on the surface A layer of a pre-curing UV curable resin on a solid master, a method of curing after transferring the resin layer to a base material, etc., and a pre-curing UV curable resin film formed on the base material, etc. And a method of forming a concavo-convex by pressing a roll-shaped master having a plurality of grooves, followed by curing.

[Polarizing layer]
The elliptically polarizing plate of the present invention has a polarizing layer next to the alignment layer B. In this polarizing layer, a composition containing a polymerizable liquid crystal compound (hereinafter, also referred to as “polarizing layer forming composition”) is applied and formed on the alignment layer B, and the dichroic dye and the polymerizable liquid crystal compound are aligned. It can produce by forming the polarizing layer which consists of a polymer of the polymerizable liquid crystal compound in. That is, when the light is anisotropically absorbed by the dichroic dye included in the liquid crystal compound, the linearly polarized light component having a vibration surface parallel to the absorption axis is absorbed, and the linearly polarized light component having a vibration surface orthogonal to the absorption axis. It becomes the polarizing plate which permeate | transmits. Such a polarizing plate is preferable in that the hue can be arbitrarily controlled by the dichroic dye and the thickness can be reduced. The composition for forming a polarizing layer may further contain a solvent, a photopolymerization initiator, a photosensitizer, a polymerization inhibitor, a leveling agent, an adhesion improver, and the like.

The polarizing layer in the elliptically polarizing plate of the present invention is usually a polymerization that is applied to the polarizing layer forming composition by applying the polarizing layer forming composition on the alignment layer B formed on a transparent substrate or the like. It is formed by polymerizing a conductive liquid crystal compound. A polarizing layer is a film | membrane with a thickness of 5 micrometers or less normally hardened | cured in the state which the polymeric liquid crystal compound orientated, Preferably it is 4 micrometers or less, More preferably, it is 3 micrometers or less. When the film thickness is larger than this range, the alignment regulating force by the alignment film is reduced, and alignment defects tend to occur.

In order to obtain polarization characteristics in the XY plane, the polymerizable liquid crystal compound may be cured in a state where the dichroic dye and the polymerizable liquid crystal compound are horizontally aligned with respect to the transparent substrate surface. In order to obtain polarization characteristics in the film thickness direction of the polarizing layer, the polymerizable liquid crystal compound may be cured in a state where the dichroic dye and the polymerizable liquid crystal compound are vertically aligned with respect to the transparent substrate surface. At this time, from the viewpoint of selectivity of polarized light absorption, preferably a polymerizable liquid crystal compound is a cured liquid crystal film cured in a smectic liquid crystal phase, and more preferably a cured liquid crystal film cured in a higher order smectic liquid crystal phase. is there. The high-order smectic liquid crystal phase here means a smectic B phase, a smectic D phase, a smectic E phase, a smectic F phase, a smectic G phase, a smectic H phase, a smectic I phase, a smectic J phase, a smectic K phase, and a smectic L phase. Among them, a smectic B phase, a smectic F phase, and a smectic I phase are more preferable.

When these higher-order smectic liquid crystal phases are used, a polarizing layer having a higher degree of orientational order can be produced. In addition, the polarizing layer produced from a high-order smectic liquid crystal phase having a high degree of orientational order can obtain a Bragg peak derived from a high-order structure such as a hexatic phase or a crystal phase in X-ray diffraction measurement. The Bragg peak is a peak derived from a molecular periodic surface periodic structure. According to the polarizing layer forming composition according to this embodiment, a polarizing layer having a periodic interval of 3.0 to 5.0 mm is obtained. be able to.

Whether or not the polymerizable liquid crystal compound exhibits a nematic liquid crystal phase or a smectic liquid crystal phase can be confirmed, for example, as follows. After forming the coating film by applying the composition for forming a polarizing layer on the substrate, the solvent contained in the coating film is removed by heat treatment under the condition that the polymerizable liquid crystal compound is not polymerized. Subsequently, the coating film formed on the substrate is heated to the isotropic phase temperature, and the liquid crystal phase that is expressed by gradually cooling is inspected by texture observation, X-ray diffraction measurement or differential scanning calorimetry using a polarizing microscope. To do. Whether the polymerizable liquid crystal compound and the dichroic dye are not phase-separated in the nematic liquid crystal phase and the smectic liquid crystal phase can be confirmed by, for example, surface observation with various microscopes or scattering degree measurement with a haze meter.

The optically anisotropic layer obtained by curing the polymerizable liquid crystal compound in a state where the dichroic dye and the polymerizable liquid crystal compound are horizontally aligned with respect to the transparent substrate surface has an absorbance A1 (λ) in the liquid crystal alignment horizontal direction with respect to light having a wavelength of λ nm. The ratio (dichroic ratio) of the absorbance A2 (λ) in the vertical direction of the liquid crystal alignment is preferably 7 or more, more preferably 20 or more, and further preferably 30 or more. The higher this value, the more the polarizing plate has better absorption selectivity. Although it depends on the type of dichroic dye, it is about 5 to 10 in the case of a liquid crystal cured film cured in a nematic liquid crystal phase.

By mixing two or more dichroic dyes having different absorption wavelengths, polarizing layers having various hues can be produced, and a polarizing layer having absorption in the entire visible light region can be obtained. By setting it as the polarizing layer which has such an absorption characteristic, it can blacken and can expand | deploy for various uses. The polarization performance of the polarizing layer can be measured using a spectrophotometer. For example, the transmittance (T1) in the transmission axis direction (orientation vertical direction) and the transmittance (T2) in the absorption axis direction (the same orientation direction) in the wavelength range of 380 nm to 780 nm, which is visible light, are applied to the spectrophotometer as a polarizer. It can be measured by the double beam method using a device with a folder attached. The polarization performance in the visible light range is calculated using the following formulas (Formula 1) and (Formula 2) to calculate the single transmittance and the degree of polarization at each wavelength, and further according to the 2 degree field of view (C light source) of JIS Z 8701. By performing the visibility correction, it is possible to calculate with the visibility correction single transmittance (Ty) and the visibility correction polarization degree (Py). Further, by calculating the chromaticity a * and b * in the L * a * b * (CIE) color system using the colorimetric function of the C light source from the transmittance measured in the same manner, the hue of the polarizing plate alone (Single hue), a hue in which the polarizing plates are arranged in parallel (parallel hue), and a hue in which the polarizing plates are arranged orthogonally (orthogonal hue) are obtained.
It can be determined that the closer the value of a * and b * is to 0, the more neutral the hue is.

Single transmittance (%) = (T1 + T2) / 2 (Formula 1)
Polarization degree (%) = (T1−T2) / (T1 + T2) × 100 (Expression 2)

[Polymerizable liquid crystal compound for forming polarizing layer]
The polymerizable liquid crystal compound 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 a 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, vinyloxy group, 1-chlorovinyl group, isopropenyl group, 4-vinylphenyl group, acryloyloxy group, methacryloyloxy group, oxiranyl group, and oxetanyl group. Among them, acryloyloxy group, methacryloyloxy group, vinyloxy group, oxiranyl group and oxetanyl group are preferable, and acryloyloxy group is more preferable. The liquid crystal may be a thermotropic liquid crystal or a lyotropic liquid crystal, but the thermotropic liquid crystal is preferable when mixed with a dichroic dye described later.

When the polymerizable liquid crystal compound is a thermotropic liquid crystal, it may be a thermotropic liquid crystal compound exhibiting a nematic liquid crystal phase or a thermotropic liquid crystal compound exhibiting a smectic liquid crystal phase. In the present invention, the polymerizable liquid crystal compound is preferably a smectic liquid crystal compound, more preferably a higher order smectic liquid crystal compound, from the viewpoint that higher polarization characteristics can be obtained. Among them, higher-order smectic liquid crystal compounds that form a smectic B phase, a smectic D phase, a smectic E phase, a smectic F phase, a smectic G phase, a smectic H phase, a smectic I phase, a smectic J phase, a smectic K phase, or a smectic L phase. More preferred are higher-order smectic liquid crystal compounds that form a smectic B phase, a smectic F phase, or a smectic I phase. When the liquid crystal phase formed by the polymerizable liquid crystal compound is such a high-order smectic phase, a polarizing layer with higher polarization performance can be produced. In addition, such a polarizing layer having a high polarization performance can obtain a Bragg peak derived from a higher order structure such as a hexatic phase or a crystal phase in X-ray diffraction measurement. The Bragg peak is a peak derived from a periodic structure of molecular orientation, and a film having a periodic interval of 3 to 6 mm can be obtained. The polarizing layer used in the present invention preferably contains a polymer of a polymerizable liquid crystal compound obtained by polymerizing the polymerizable liquid crystal compound in a smectic phase from the viewpoint of obtaining higher polarization characteristics.

Specific examples of such a compound include a compound represented by the following formula (A) (hereinafter sometimes referred to as compound (A)). The said polymeric liquid crystal compound may be used independently and may be used in combination of 2 or more type.

U ¹ −V ¹ −W ¹ −X ¹ −Y ¹ −X ² −Y ² −X ³ −W ² −V ² −U ² (A)
[In the formula (A),
X ¹ , X ² and X ³ each independently represent a divalent aromatic group or a divalent alicyclic hydrocarbon group, wherein the divalent aromatic group or divalent alicyclic group The hydrogen atom contained in the hydrocarbon group is substituted with a halogen atom, an alkyl group having 1 to 4 carbon atoms, a fluoroalkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a cyano group, or a nitro group. The carbon atom constituting the divalent aromatic group or divalent alicyclic hydrocarbon group may be substituted with an oxygen atom, a sulfur atom or a nitrogen atom. Provided that at least one of X ¹ , X ² and X ³ is a 1,4-phenylene group which may have a substituent or a cyclohexane-1,4-diyl group which may have a substituent It is.
Y ¹ , Y ² , W ¹ and W ² are each independently a single bond or a divalent linking group.
V ¹ and V ² each independently represent an optionally substituted alkanediyl group having 1 to 20 carbon atoms, and —CH ₂ — constituting the alkanediyl group is —O—, — S- or -NH- may be substituted.
U ¹ and U ² each independently represent a polymerizable group or a hydrogen atom, and at least one is a polymerizable group.

In the compound (A), at least one of X ¹ , X ² and X ³ is a 1,4-phenylene group which may have a substituent, or a cyclohexane which may have a substituent A 1,4-diyl group is preferred. In particular, X ¹ and X ³ are more preferably a cyclohexane-1,4-diyl group which may have a substituent, and the cyclohexane-1,4-diyl group is trans-cyclohexane. More preferred is a -1,4-diyl group. When the structure of trans-cyclohexane-1,4-diyl group is included, smectic liquid crystallinity tends to be easily developed. In addition, the optionally substituted 1,4-phenylene group or the optionally substituted cyclohexane-1,4-diyl group may be a methyl group , An alkyl group having 1 to 4 carbon atoms such as an ethyl group and a butyl group, a cyano group, and a halogen atom such as a chlorine atom and a fluorine atom, but are preferably unsubstituted.

Y ¹ and Y ² each independently represent a single bond, —CH ₂ CH ₂ —, —CH ₂ O—, —COO—, —OCO—, —N═N—, —CR ^a ═CR ^b —, — C≡C— or CR ^a ═N— is preferred, and R ^a and R ^b each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Y ¹ and Y ² are more preferably —CH ₂ CH ₂ —, —COO—, —OCO— or a single bond, and more preferably Y ¹ and Y ² are different from each other. When Y ¹ and Y ² are different from each other, smectic liquid crystallinity tends to be easily developed.

W ¹ and W ² are each independently preferably a single bond, —O—, —S—, —COO— or OCO—, and more preferably each independently a single bond or —O—.

Examples of the alkanediyl group having 1 to 20 carbon atoms represented by V ¹ and V ² include a methylene group, an ethylene group, a propane-1,3-diyl group, a butane-1,3-diyl group, and a butane-1,4. -Diyl group, 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 and icosane-1,20-diyl group. V ¹ and V ² are preferably an alkanediyl group having 2 to 12 carbon atoms, and more preferably a linear alkanediyl group having 6 to 12 carbon atoms. By using a straight-chain alkanediyl group having 6 to 12 carbon atoms, the crystallinity is improved and smectic liquid crystallinity tends to be easily exhibited.
Examples of the substituent that the optionally substituted alkanediyl group having 1 to 20 carbon atoms has include a cyano group and a halogen atom such as a chlorine atom and a fluorine atom. The alkanediyl group includes It is preferably unsubstituted, and more preferably an unsubstituted and linear alkanediyl group.

U ¹ and U ² are both preferably a polymerizable group, more preferably a photopolymerizable group. Since the polymerizable liquid crystal compound having a photopolymerizable group can be polymerized under a lower temperature condition than the thermally polymerizable group, it is advantageous in that the liquid crystal can form a polymer with a higher degree of order.

The polymerizable groups represented by U ¹ and U ² may be different from each other, but are preferably the same. Examples of the polymerizable group include a vinyl group, vinyloxy group, 1-chlorovinyl group, isopropenyl group, 4-vinylphenyl group, acryloyloxy group, methacryloyloxy group, oxiranyl group, and oxetanyl group. Among them, acryloyloxy group, methacryloyloxy group, vinyloxy group, oxiranyl group and oxetanyl group are preferable, and methacryloyloxy group or acryloyloxy group is more preferable.

Examples of such polymerizable liquid crystal compounds include the following.

Among the exemplified compounds, the formula (1-2), formula (1-3), formula (1-4), formula (1-6), formula (1-7), formula (1-8), formula At least one selected from the group consisting of compounds represented by (1-13), formula (1-14) and formula (1-15) is preferred.

The exemplified compound (A) can be used alone or in combination for the polarizing layer. Moreover, when combining 2 or more types of polymeric liquid crystal compounds, it is preferable that at least 1 type is a compound (A), and it is more preferable that 2 or more types are a compound (A). By combining two or more polymerizable liquid crystal compounds, liquid crystallinity may be temporarily maintained even at a temperature lower than the liquid crystal-crystal phase transition temperature. The mixing ratio when combining two kinds of polymerizable liquid crystal compounds is usually 1:99 to 50:50, preferably 5:95 to 50:50, more preferably 10:90 to 50:50. It is.

Compound (A) is, for example, Lub et al. Recl. Trav. Chim. It is manufactured by a known method described in Pays-Bas, 115, 321-328 (1996), or Japanese Patent No. 4719156.

The content of the polymerizable liquid crystal compound in the composition for forming a polarizing layer is usually 50 to 99.5 parts by weight, preferably 60 to 99 parts by weight, based on 100 parts by weight of the solid content of the composition for forming a polarizing layer. More preferably, it is 70 to 98 parts by mass, and still more preferably 80 to 97 parts by mass. If the content ratio of the polymerizable liquid crystal compound is within the above range, the orientation tends to be high. Here, solid content means the total amount of the component remove | excluding the solvent from the composition for polarizing layer formation.

[Dichroic dye for polarizing layer formation]
A dichroic dye refers to a dye having the property that the absorbance in the major axis direction of a molecule is different from the absorbance in the minor axis direction. The dichroic dye preferably has a property of absorbing visible light, and more preferably has an absorption maximum wavelength (λMAX) in the range of 380 to 680 nm. Examples of such dichroic dyes include acridine dyes, oxazine dyes, cyanine dyes, naphthalene dyes, azo dyes and anthraquinone dyes, and among them, azo dyes are preferable. Examples of the azo dye include monoazo dyes, bisazo dyes, trisazo dyes, tetrakisazo dyes, and stilbene azo dyes, and bisazo dyes and trisazo dyes are preferable. Dichroic dyes may be used alone or in combination, but in order to obtain absorption in the entire visible light range, it is preferable to combine three or more types of dichroic dyes, and more preferable to combine three or more types of azo dyes. preferable.

Examples of the azo dye include a compound represented by the formula (B) (hereinafter sometimes referred to as “compound (B)”).
T ¹ -A ¹ (-N = NA ² ) _p -N = NA ³ -T ² (B)
[In the formula (B)
A ¹ and A ² and A ³ are independently of each other an optionally substituted 1,4-phenylene group, naphthalene-1,4-diyl group or an optionally substituted divalent group. A ¹ and / or A ² is a 1,4-phenylene group, T ¹ and T ² are electron withdrawing groups or electron emitting groups, and are substantially in the azo bond plane. At 180 ° position. p represents an integer of 0 to 4. When p is 2, two A ² may be the same or different from each other. ]

Examples of the substituent that the 1,4-phenylene group, naphthalene-1,4-diyl group and divalent heterocyclic group in A ¹ and A ² and A ³ optionally have include a methyl group, an ethyl group, and a butyl group. 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; a fluorinated alkyl group having 1 to 4 carbon atoms such as a trifluoromethyl group; a cyano group; a nitro group A halogen atom such as a chlorine atom or a fluorine atom; a substituted or unsubstituted amino group such as an amino group, a diethylamino group or a pyrrolidino group (a substituted amino group is an amino group having one or two alkyl groups having 1 to 6 carbon atoms); Or an amino group in which two substituted alkyl groups are bonded to each other to form an alkanediyl group having 2 to 8 carbon atoms. Is H _2.) Can be mentioned. Examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, and a hexyl group. Examples of the alkanediyl group having 2 to 8 carbon atoms include ethylene group, propane-1,3-diyl group, butane-1,3-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group Hexane-1,6-diyl group, heptane-1,7-diyl group, octane-1,8-diyl group and the like. For inclusion in a highly ordered liquid crystal structure such as a smectic liquid crystal, A ¹ and A ² and A ³ are unsubstituted, 1,4-phenylene groups in which hydrogen is substituted with methyl groups or methoxy groups, or divalent groups The heterocyclic group is preferably, and p is preferably 0 or 1. Among them, p is 1 and at least two of the three structures A ^1, A ² and A ³ are 1,4-phenylene groups in that both molecular synthesis is easy and high performance is achieved. More preferred.

Examples of the divalent heterocyclic group include groups in which two hydrogen atoms have been removed from quinoline, thiazole, benzothiazole, thienothiazole, imidazole, benzimidazole, oxazole and benzoxazole. When A ² is a divalent heterocyclic group, a structure in which the molecular bond angle is substantially 180 ° is preferable. Specifically, benzothiazole, benzimidazole, benzoxazole in which two 5-membered rings are condensed A structure is more preferable.

T ¹ and T ² are an electron withdrawing group or an electron emitting group, and preferably have different structures, and T ¹ is an electron withdrawing group and a T ² electron emitting group, or T ¹ is an electron emitting group and a T ² electron withdrawing group. More preferably, it is a group relationship. Specifically, T ¹ and T ² are each independently one alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a cyano group, a nitro group, or an alkyl group having 1 to 6 carbon atoms. An amino group having two amino groups, or an amino group in which two substituted alkyl groups are bonded to each other to form an alkanediyl group having 2 to 8 carbon atoms, or a trifluoromethyl group is preferable. In order to be included in the liquid crystal structure, it is necessary to have a structure in which the excluded volume of the molecule is smaller, so that the alkyl group having 1 to 4 carbon atoms, the alkoxy group having 1 to 4 carbon atoms, the cyano group, and the carbon number 1 An amino group having one or two alkyl groups of ˜6 or an amino group in which two substituted alkyl groups are bonded to each other to form an alkanediyl group having 2 to 8 carbon atoms is preferred.

Examples of such azo dyes include the following.

In formulas (2-1) to (2-6),
B ¹ to B ²⁰ each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a cyano group, a nitro group, a substituted or unsubstituted amino group (a 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 each independently represents an integer of 0 to 3.
When n1 is 2 or more, the plurality of B ² may be the same or different,
When n2 is 2 or more, the plurality of B ⁶ may be the same or different,
When n3 is 2 or more, the plurality of B ⁹ may be the same or different,
When n4 is 2 or more, the plurality of B ¹⁴ may be the same or different.

The anthraquinone dye is preferably a compound represented by the formula (2-7).

[In the formula (2-7),
R ¹ to R ⁸ each 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. ]

The oxazine dye is preferably a compound represented by the formula (2-8).

[In the formula (2-8),
R ⁹ to R ¹⁵ each 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. ]

The acridine dye is preferably a compound represented by the formula (2-9).

[In the formula (2-9),
R ¹⁶ to R ²³ each 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 formula (2-7), formula (2-8) and formula (2-9), examples of the alkyl group having 1 to 4 carbon atoms represented by R ^x include a methyl group, an ethyl group, a propyl group, and a butyl group. A pentyl group, a hexyl group, and the like. Examples of the aryl group having 6 to 12 carbon atoms include a phenyl group, a toluyl group, a xylyl group, and a naphthyl group.

As the cyanine dye, a compound represented by the formula (2-10) and a compound represented by the formula (2-11) are preferable.

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

n5 represents an integer of 1 to 3. ]

[In the formula (2-11),
D ³ and D ⁴ each independently represent a group represented by any one of formulas (2-11a) to (2-11h).

n6 represents an integer of 1 to 3. ]

The content of the dichroic dye (the total amount when there are a plurality of types) is usually 1 to 30 parts by mass with respect to 100 parts by mass of the polymerizable liquid crystal compound from the viewpoint of obtaining good light absorption characteristics. The amount is preferably 2 to 20 parts by mass, more preferably 3 to 15 parts by mass. If the content of the dichroic dye is less than this range, light absorption becomes insufficient and sufficient polarization performance cannot be obtained, and if it is more than this range, the alignment of liquid crystal molecules may be inhibited.

[Angle formed by polarizing layer and retardation layer]
In the elliptically polarizing plate of the present invention, the optical axis of the polarizing layer and the retardation layer is substantially parallel, that is, the optical axis of the polarizing layer and the optical axis of the retardation layer are substantially in the plane of the elliptically polarizing plate. The optical axis of the polarizing layer and the optical axis of the retardation layer intersect in the plane of the elliptically polarizing plate, not the relationship that does not intersect. The angle formed by the optical axis of the polarizing layer and the optical axis of the retardation layer that intersect each other is preferably 40 to 50 °, which is the angle formed by the slow axis of the retardation layer and the absorption axis of the polarizing layer, and is 41 to 49. More preferably, the angle is more preferably from 43 to 47 °, particularly preferably substantially 45 °, and ideally 45 °. The ellipticity is improved when the angle formed by the retardation axis of the retardation layer and the absorption axis of the polarizing layer is within the above range, and the polarizing plate of the present invention substantially functions as a circularly polarizing plate particularly when the angle is 45 °. .

[solvent]
As the solvent, a solvent capable of completely dissolving the polymerizable liquid crystal compound used in forming the retardation layer or polarizing layer is preferable, and a solvent inert to the polymerization reaction of the polymerizable liquid crystal compound is preferable.
Examples of the solvent include alcohol solvents such as methanol, ethanol, ethylene glycol, isopropyl alcohol, propylene glycol, ethylene glycol methyl ether, ethylene glycol butyl ether, and propylene glycol monomethyl ether; ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, γ -Ester solvents such as butyrolactone, propylene glycol methyl ether acetate and ethyl lactate; ketone solvents such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, 2-heptanone and methyl isobutyl ketone; aliphatic hydrocarbon solvents such as pentane, hexane and heptane Aromatic hydrocarbon solvents such as toluene and xylene; nitrile solvents such as acetonitrile; tetrahydride Ether solvents such as furan and dimethoxyethane; chlorine-containing solvents such as chloroform and chlorobenzene; amide solvents such as dimethylacetamide, dimethylformamide, N-methyl-2-pyrrolidone and 1,3-dimethyl-2-imidazolidinone Etc. These solvents may be used alone or in combination of two or more. Among these, alcohol solvents, ester solvents, ketone solvents, chlorine-containing solvents, amide solvents, and aromatic hydrocarbon solvents are preferable.

The content of the solvent in 100 parts by weight of the composition is preferably 50 parts by weight to 98 parts by weight, and more preferably 70 parts by weight to 95 parts by weight. Accordingly, the solid content in 100 parts by mass of the composition is preferably 2 to 50 parts by mass. When the solid content of the composition is 50 parts by mass or less, since the viscosity of the composition is low, the thickness of the film containing the polymerizable liquid crystal compound becomes substantially uniform, and unevenness occurs in the film containing the polymerizable liquid crystal compound. It tends to be difficult. The solid content can be appropriately determined in consideration of the thickness of the film containing the polymerizable liquid crystal compound to be produced.

[Photopolymerization initiator]
The polymerization initiator is a compound that can initiate a polymerization reaction such as a polymerizable liquid crystal compound. As a polymerization initiator, the photoinitiator which generate | occur | produces a radical by light irradiation is more preferable.
Examples of the photopolymerization initiator include benzoin compounds, benzophenone compounds, benzyl ketal compounds, α-hydroxy ketone compounds, α-amino ketone compounds, triazine compounds, iodonium salts, and sulfonium salts. Specifically, Irgacure (registered trademark) 907, Irgacure 184, Irgacure 651, Irgacure 819, Irgacure 250, Irgacure 369, Irgacure 379, Irgacure 127, Irgacure 2959, Irgacure 754, Irgacure 379EG (above, BASF Japan Ltd.) ), Sequol BZ, Sequol Z, Sequol BEE (above, Seiko Chemical Co., Ltd.), kayacure BP100 (Nippon Kayaku Co., Ltd.), Kayacure UVI-6992 (Dow), Adekaoptomer SP- 152, Adekaoptomer SP-170, Adekaoptomer N-1717, Adekaoptomer N-1919, Adeka Arkles NCI-831, Adeka Arkles NCI-930 (and above, shares) Company ADEKA), TAZ-A, TAZ-PP (Nippon Siebel Hegner, Inc.) and TAZ-104 (Sanwa Chemical Co., Ltd.).
In the composition for forming a retardation layer or the composition for forming a polarizing layer, the contained photopolymerization initiator is at least one, and preferably one or two.

Since the photopolymerization initiator can fully utilize the energy emitted from the light source and is excellent in productivity, the maximum absorption wavelength is preferably 300 nm to 380 nm, more preferably 300 nm to 360 nm, and among these, α- An acetophenone polymerization initiator and an oxime photopolymerization initiator are preferred.

Examples of α-acetophenone compounds include 2-methyl-2-morpholino-1- (4-methylsulfanylphenyl) propan-1-one, 2-dimethylamino-1- (4-morpholinophenyl) -2-benzylbutane-1 -One and 2-dimethylamino-1- (4-morpholinophenyl) -2- (4-methylphenylmethyl) butan-1-one, and the like, more preferably 2-methyl-2-morpholino-1- ( 4-methylsulfanylphenyl) propan-1-one and 2-dimethylamino-1- (4-morpholinophenyl) -2-benzylbutan-1-one. Examples of commercially available α-acetophenone compounds include Irgacure 369, 379EG, 907 (above, manufactured by BASF Japan Ltd.), Sequol BEE (manufactured by Seiko Chemical Co., Ltd.), and the like.

The oxime photopolymerization initiator generates methyl radicals when irradiated with light. Polymerization of the polymerizable liquid crystal compound in the deep part of the film containing the polymerizable liquid crystal compound suitably proceeds by this methyl radical. Moreover, it is preferable to use the photoinitiator which can utilize the ultraviolet-ray with a wavelength of 350 nm or more efficiently from a viewpoint that the polymerization reaction in the deep part of the film | membrane containing a polymeric liquid crystal compound advances more efficiently. As a photopolymerization initiator capable of efficiently using ultraviolet rays having a wavelength of 350 nm or more, a triazine compound or an oxime ester type carbazole compound is preferable, and an oxime ester type carbazole compound is more preferable from the viewpoint of sensitivity. Examples of oxime ester type carbazole compounds include 1,2-octanedione, 1- [4- (phenylthio) -2- (O-benzoyloxime)], ethanone, 1- [9-ethyl-6- (2-methylbenzoyl) ) -9H-carbazol-3-yl] -1- (O-acetyloxime) and the like. Commercially available oxime ester type carbazole compounds include Irgacure OXE-01, Irgacure OXE-02, Irgacure OXE-03 (above, manufactured by BASF Japan Ltd.), Adekaoptomer N-1919, Adeka Arcles NCI-831 (above ADEKA Co., Ltd.).

The addition amount of the photopolymerization initiator is usually 0.1 to 30 parts by weight, preferably 1 to 20 parts by weight, more preferably 3 parts per 100 parts by weight of the polymerizable liquid crystal compound. Parts by mass to 18 parts by mass. If it is in the said range, reaction of a polymeric group will fully advance and it will be hard to disturb the orientation of a polymeric liquid crystal compound.

By adding a polymerization inhibitor, the polymerization reaction of the polymerizable liquid crystal compound can be controlled. Polymerization inhibitors include hydroquinones having substituents such as hydroquinone and alkyl ethers; catechols having substituents such as alkyl ethers such as butylcatechol; pyrogallols, 2,2,6,6-tetramethyl-1- And radical scavengers such as piperidinyloxy radical; thiophenols; β-naphthylamines and β-naphthols. In order to polymerize the polymerizable liquid crystal compound without disturbing the orientation of the polymerizable liquid crystal compound, the content of the polymerization inhibitor is usually 0.1 to 10 parts by mass with respect to 100 parts by mass of the polymerizable liquid crystal compound. Yes, preferably 0.5 to 5 parts by mass, and more preferably 0.5 to 3 parts by mass.

Furthermore, the sensitivity of the photopolymerization initiator can be increased by using a photosensitizer. Examples of the photosensitizer include xanthones such as xanthone and thioxanthone; anthracene having a substituent such as anthracene and alkyl ether; phenothiazine; and rubrene. Examples of the photosensitizer include xanthones such as xanthone and thioxanthone; anthracene having a substituent such as anthracene and alkyl ether; phenothiazine; and rubrene. The content of the photosensitizer is usually 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight, more preferably 0.5 to 5 parts by weight with respect to 100 parts by weight of the polymerizable liquid crystal compound. 3 parts by mass.

[Leveling agent]
The leveling agent is an additive having a function of adjusting the fluidity of the composition and flattening a film obtained by applying the composition. For example, an organic modified silicone oil system, polyacrylate system and perfluorocarbon An alkyl type leveling agent is mentioned. Specifically, DC3PA, SH7PA, DC11PA, SH28PA, SH29PA, SH30PA, ST80PA, ST86PA, SH8400, SH8700, FZ2123 (all are manufactured by Toray Dow Corning Co., Ltd.), KP321, KP323, KP324, KP326, KP340, KP341, X22-161A, KF6001 (all manufactured by Shin-Etsu Chemical Co., Ltd.), TSF400, TSF401, TSF410, TSF4300, TSF4440, TSF4445, TSF-4446, TSF4452, TSF4460 (all, Momentive Performance Materials Japan GK) Manufactured), Fluorinert (registered trademark) FC-72, FC-40, FC-43, FC-3283 (above, Manufactured by Sumitomo 3M Co., Ltd.), MegaFace (registered trademark) R-08, R-30, R-90, F-410, F-411, F-443, F-445, F-470, F-477, F-479, F-482, F-482 (all of which are manufactured by DIC Corporation), Ftop (trade name) EF301, EF303, EF351, EF352 (all from Mitsubishi Materials Electronics Chemical Co., Ltd.), Surflon (registered trademark) S-381, S-382, S-383, S-393, SC-101, SC-105, KH -40, SA-100 (all are manufactured by AGC Seimi Chemical Co., Ltd.), trade names E1830, E5844 (manufactured by Daikin Fine Chemical Laboratory Co., Ltd.), BM-1000, BM-1100, BYK-352, BY -353 and BYK-361N (both trade name: BM Chemie Co., Ltd.), and the like. Of these, polyacrylate leveling agents and perfluoroalkyl leveling agents are preferred.

The content of the leveling agent in the retardation layer forming composition and polarizing layer forming composition used in the present invention is preferably 0.01 parts by mass to 5 parts by mass with respect to 100 parts by mass of the polymerizable liquid crystal compound. 0.1 to 3 parts by mass is more preferable. It is preferable that the content of the leveling agent is within the above range because the polymerizable liquid crystal compound can be easily horizontally aligned and the resulting film containing the polymerizable liquid crystal compound tends to be smoother. The retardation layer forming composition and the polarizing layer forming composition used in the present invention may contain two or more kinds of leveling agents.

[Adhesive]
Examples of the adhesive for bonding the polarizing layer and the retardation layer or the retardation layer and the display device include a pressure-sensitive adhesive, a dry-solidifying adhesive, and a chemically reactive adhesive. Examples of the chemically reactive adhesive include an active energy ray curable adhesive. As the adhesive between the polarizing layer and the retardation layer, an adhesive layer formed from a pressure-sensitive adhesive, a dry-solidifying adhesive, or an active energy ray-curable adhesive is preferable. As the adhesive between the apparatus and the apparatus, a pressure-sensitive adhesive or an adhesive layer formed from an active energy ray-curable adhesive is preferable.

The pressure-sensitive adhesive usually contains a polymer and may contain a solvent.
Examples of the polymer include acrylic polymers, silicone polymers, polyesters, polyurethanes, and polyethers. Among them, acrylic pressure-sensitive adhesives containing acrylic polymers have excellent optical transparency, moderate wettability and cohesive strength, excellent adhesion, and high weather resistance and heat resistance. It is preferable because it does not easily float or peel off under humidifying conditions.

Acrylic polymers include (meth) acrylates in which the alkyl group in the ester moiety is an alkyl group having 1 to 20 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 may be collectively referred to as (meth) acrylic acid) and (meth) having a functional group such as (meth) acrylic acid or hydroxyethyl (meth) acrylate A copolymer with an acrylic monomer is preferred.

A pressure-sensitive adhesive containing such a copolymer is excellent in adhesiveness, and even when removed after being bonded to a display device, it is relatively easy to remove without causing adhesive residue or the like on the display device. Is preferable. The glass transition temperature of the acrylic polymer is preferably 25 ° C. or less, and more preferably 0 ° C. or less. The mass average molecular weight of such an acrylic polymer is preferably 100,000 or more.

Examples of the solvent include the solvents mentioned as the solvent. The pressure-sensitive adhesive may contain a light diffusing agent. The light diffusing agent is an additive that imparts light diffusibility to the pressure-sensitive adhesive, and may be fine particles having a refractive index different from the refractive index of the polymer included in the pressure-sensitive adhesive. Examples of the light diffusing agent include fine particles made of an inorganic compound and fine particles made of an organic compound (polymer). Many of the polymers that the adhesive contains as an active ingredient, including acrylic polymers, have a refractive index of about 1.4 to 1.6. It is preferable to select appropriately. The refractive index difference 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 is preferably 0.01 to 0.2 from the viewpoint of the brightness and display properties of the display device. The fine particles used as the light diffusing agent are preferably spherical fine particles, and fine particles close to monodispersion, more preferably fine particles having an average particle diameter of 2 μm to 6 μm. The refractive index is measured by a general minimum deviation method or Abbe refractometer.
Examples of the fine particles made of an inorganic compound include aluminum oxide (refractive index 1.76) and silicon oxide (refractive index 1.45). Fine particles comprising an organic compound (polymer) include melamine beads (refractive index 1.57), polymethyl methacrylate beads (refractive index 1.49), methyl methacrylate / styrene copolymer resin beads (refractive index 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), and silicone. Examples thereof include resin beads (refractive index: 1.46). The content of the light diffusing agent is usually 3 to 30 parts by mass with respect to 100 parts by mass of the polymer.
The thickness of the pressure-sensitive adhesive is determined according to its adhesion and the like and is not particularly limited, but is usually 1 μm to 40 μm. From the viewpoint of processability and durability, the thickness is preferably 3 μm to 25 μm, more preferably 5 μm to 20 μm. By making the thickness of the adhesive layer formed from the adhesive 5 μm to 20 μm, the brightness of the display device when viewed from the front or obliquely is maintained, and blurring or blurring of the display image is prevented. It can be made difficult to occur.

[Dry-solidifying adhesive]
The dry-solidifying adhesive may contain a solvent.
The dry-solidifying adhesive contains, as a main component, a polymer of a monomer having a protonic functional group such as a hydroxyl group, a carboxyl group or an amino group and an ethylenically unsaturated group, or a urethane resin. Examples include aldehydes, epoxy compounds, epoxy resins, melamine compounds, zirconia compounds, and compositions containing a curable compound such as a zinc compound. Examples of the polymer of a monomer having a protonic functional group such as a hydroxyl group, a carboxyl group or an amino group and an ethylenically unsaturated group include an ethylene-maleic acid copolymer, an itaconic acid copolymer, an acrylic acid copolymer, and an acrylamide. Examples include copolymers, saponified products of polyvinyl acetate, and polyvinyl alcohol resins.

Examples of the polyvinyl alcohol resin include polyvinyl alcohol, 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. Can be mentioned. The content of the polyvinyl alcohol-based resin in the aqueous adhesive is usually 1 to 10 parts by mass, preferably 1 to 5 parts by mass with respect to 100 parts by mass of water.

Examples of the urethane resin include polyester ionomer type urethane resins.
The polyester ionomer type urethane resin here is a urethane resin having a polyester skeleton, and a resin in which a small amount of an ionic component (hydrophilic component) is introduced. Since such an ionomer type urethane resin is emulsified in water without using an emulsifier and becomes an emulsion, it can be an aqueous adhesive. When a polyester ionomer type urethane resin is used, it is effective to blend a water-soluble epoxy compound as a crosslinking agent.

Examples of the epoxy resin include a polyamide epoxy resin obtained by reacting a polyalkylene polyamine such as diethylenetriamine or triethylenetetramine with a dicarboxylic acid such as adipic acid and epichlorohydrin. Commercially available products of such polyamide epoxy resins include “Smilease Resin (registered trademark) 650” and “Smilease Resin 675” (above, manufactured by Sumika Chemtex Co., Ltd.), “WS-525” (manufactured by Nippon PMC Co., Ltd.). Etc. When the epoxy resin is blended, the addition amount is usually 1 part by mass to 100 parts by mass, preferably 1 part by mass to 50 parts by mass with respect to 100 parts by mass of the polyvinyl alcohol resin.

The thickness of the adhesive layer formed from the dry-solidifying adhesive is usually 0.001 μm to 5 μm, preferably 0.01 μm to 2 μm, more preferably 0.01 μm to 0.5 μm. is there. If the adhesive layer formed from the dry-solidifying adhesive is too thick, the optically anisotropic layer tends to be defective in appearance.

[Active energy ray-curable adhesive]
The active energy ray-curable adhesive may contain a solvent. An active energy ray-curable adhesive is an adhesive that cures upon irradiation with active energy rays.
Examples of the active energy ray-curable adhesive include a cationic polymerizable adhesive containing an epoxy compound and a cationic polymerization initiator, a radical polymerizable adhesive containing an acrylic curing component and a radical polymerization initiator, and an epoxy compound. Contains both a cationic polymerizable curing component such as an acrylic compound and a radical polymerizable curing component such as an acrylic compound, and further contains an adhesive containing a cationic polymerization initiator and a radical polymerization initiator, and these polymerization initiators. For example, an adhesive that is cured by irradiating an electron beam.

Among them, radically polymerizable active energy ray-curable adhesives containing an acrylic curing component and a radical polymerization initiator, and cationic polymerizable active energy ray-curable adhesives containing an epoxy compound and a cationic polymerization initiator are provided. preferable. Examples of the acrylic curing component include (meth) acrylates such as methyl (meth) acrylate and hydroxyethyl (meth) acrylate, and (meth) acrylic acid. The active energy ray-curable adhesive containing an epoxy compound may further contain a compound other than the epoxy compound. Examples of compounds other than epoxy compounds include oxetane compounds and acrylic compounds.
Examples of the radical polymerization initiator include the photopolymerization initiators described above. As a commercial product of a cationic polymerization initiator, “Kayarad” (registered trademark) series (manufactured by Nippon Kayaku Co., Ltd.), “Syracure UVI” series (manufactured by Dow Chemical Co., Ltd.), “CPI” series (manufactured by San Apro Corporation) “TAZ”, “BBI” and “DTS” (manufactured by Midori Chemical Co., Ltd.), “Adekaoptomer” series (manufactured by ADEKA Corporation), “RHODORSIL” (registered trademark) (manufactured by Rhodia Corporation) It is done. The content of the radical polymerization initiator and the cationic polymerization initiator is usually 0.5 to 20 parts by mass, preferably 1 to 15 parts by mass with respect to 100 parts by mass of the active energy ray-curable adhesive. Part.

The active energy ray-curable adhesive further contains an ion trap agent, an antioxidant, a chain transfer agent, a tackifier, a thermoplastic resin, a filler, a flow regulator, a plasticizer, an antifoaming agent, and the like. May be.

In this specification, the active energy ray is defined as an energy ray capable of decomposing a compound that generates active species to generate active species. Examples of such active energy rays include visible light, ultraviolet rays, infrared rays, X-rays, α rays, β rays, γ rays, and electron beams, and ultraviolet rays and electron beams are preferable. Preferable ultraviolet irradiation conditions are the same as the polymerization of the polymerizable liquid crystal compound described above.

[Refractive index of each layer of laminate]
When another layer B is laminated immediately below a certain layer A, assuming that the refractive index of the layer A is nA and the refractive index of the layer B is nB, the layer when light enters from a direction perpendicular to the layer A The interface reflectance in A and layer B is expressed by the following equation (K).
Interface reflectance (%) = (n _A −n _B ) ² / (n _A + n _B ) ² × 100 (K)

For this reason, when the difference in refractive index between adjacent layers of the laminate is large, loss due to interface reflection increases. In the elliptically polarizing plate made of a laminate, the refractive index difference between adjacent layers is preferably 0.20 or less, more preferably 0.15 or less, and 0.10 or less in order to reduce the influence of loss due to interface reflection. More preferably it is.

[Method for producing polarizing layer or retardation layer]
Hereinafter, the polarizing layer or retardation layer of the present invention may be referred to as an optically anisotropic layer. The composition for forming a polarizing layer or the composition for forming a retardation layer may be referred to as an optically anisotropic layer forming composition. The manufacturing method of the polarizing layer and the retardation layer may be the same or different.

[Coating of composition for forming optically anisotropic layer]
An optically anisotropic layer can be formed by applying the optically anisotropic layer forming composition on the transparent substrate or the alignment film. As a method for applying the optically anisotropic layer forming composition on the substrate, extrusion coating method, direct gravure coating method, reverse gravure coating method, CAP coating method, slit coating method, micro gravure method, die coating method, An ink jet method is exemplified. Moreover, the method of apply | coating using coaters, such as a dip coater, a bar coater, a spin coater, etc. are mentioned. In particular, when applying continuously in the Roll to Roll format, a coating method by a microgravure method, an ink jet method, a slit coating method, or a die coating method is preferable, and when applying to a single-wafer substrate such as glass, uniformity is achieved. A high spin coating method is preferred. In the case of coating in the Roll to Roll format, a composition for forming a photo-alignment film or the like is applied to a substrate to form an alignment film, and the composition for forming an optical anisotropic layer is continuously formed on the obtained alignment film. It can also be applied.

[Drying of composition for forming optically anisotropic layer]
Examples of the drying method for removing the solvent contained in the composition for forming an optically anisotropic layer include natural drying, ventilation drying, heat drying, reduced pressure drying, and a combination thereof. Of these, natural drying or heat drying is preferred. The drying temperature is preferably in the range of 0 to 200 ° C, more preferably in the range of 20 to 150 ° C, and still more preferably in the range of 50 to 130 ° C. The drying time is preferably 10 seconds to 20 minutes, more preferably 30 seconds to 10 minutes. The composition for forming a photo-alignment film and the alignment polymer composition can be similarly dried.

[Polymerization of polymerizable liquid crystal compound]
Photopolymerization is preferred as a method for polymerizing the polymerizable liquid crystal compound. Photopolymerization is carried out by irradiating an active energy ray to a laminate in which a composition for forming an optically anisotropic layer containing a polymerizable liquid crystal compound is applied on a substrate or an alignment film. The active energy rays to be irradiated include the type of polymerizable liquid crystal compound contained in the dry film (particularly, the type of photopolymerizable functional group of the polymerizable liquid crystal compound), and a photopolymerization initiator when it contains a photopolymerization initiator. Depending on the type and amount thereof, it is appropriately selected. Specific examples include one or more kinds of light selected from the group consisting of visible light, ultraviolet light, infrared light, X-rays, α-rays, β-rays, and γ-rays. Among them, ultraviolet light is preferable in that it is easy to control the progress of the polymerization reaction and that a photopolymerization apparatus widely used in this field can be used. It is preferable to select the kind of the liquid crystalline compound.

Examples of the light source of the active energy ray include a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a xenon lamp, a halogen lamp, a carbon arc lamp, a tungsten lamp, a gallium lamp, an excimer laser, and a wavelength range. Examples include LED light sources that emit light of 380 to 440 nm, chemical lamps, black light lamps, microwave-excited mercury lamps, metal halide lamps, and the like.

Ultraviolet irradiation intensity is ^{usually, 10mW / cm 2 ~ 3,000mW /} cm 2. The ultraviolet irradiation intensity is preferably an intensity in a wavelength region effective for activating the cationic polymerization initiator or radical polymerization initiator. The time for light irradiation is usually 0.1 second to 10 minutes, preferably 0.1 second to 5 minutes, more preferably 0.1 seconds to 3 minutes, and further preferably 0.1 seconds. ~ 1 minute. When irradiating once or a plurality of times with such ultraviolet irradiation intensity, the accumulated light quantity is usually 10 mJ / cm ² to 3,000 mJ / cm ² , preferably 50 mJ / cm ² to 2,000 mJ / cm ² , more preferably it is ^{100mJ / cm 2 ~ 1,000mJ / cm} 2. When the integrated light quantity is less than this range, the polymerizable liquid crystal compound is not sufficiently cured. On the contrary, when the integrated light quantity is more than this range, the elliptically polarizing plate including the optically anisotropic layer may be colored.

[Display device]
The present invention can provide a display device including the retardation plate of the present invention as one embodiment. The display device may include the elliptically polarizing plate according to the embodiment.
The display device is a device having a display mechanism, 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 (field emission display devices (FED, etc.), surface field emission display devices. (SED)), electronic paper (display device using electronic ink or electrophoretic element), plasma display device, projection display device (grating light valve (GLV) display device, display device having digital micromirror device (DMD)) Etc.) 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 liquid crystal display device, and the like. These display devices may be a display device that displays a two-dimensional image, or may be a stereoscopic display device that displays a three-dimensional image. In particular, an organic EL display device and a touch panel display device are preferable as the display device including the retardation layer and the polarizing layer according to the present invention.

Hereinafter, although an example and a comparative example explain the present invention still in detail, the present invention is not limited to these examples. Unless otherwise specified, “%” and “part” in Examples and Comparative Examples are “% by mass” and “part by mass”.
The polymer films, apparatuses and measurement methods used in Examples 1 to 6 and Comparative Examples 1 and 2 are as follows.
-ZF-14 made by Nippon Zeon Co., Ltd. was used for the cycloolefin polymer (COP) film.
-AGF-B10 manufactured by Kasuga Electric Co., Ltd. was used as the corona treatment device.
The corona treatment was performed once using the above corona treatment device under the conditions of an output of 0.3 kW and a treatment speed of 3 m / min.
-SPOT CURE SP-7 with a polarizer unit manufactured by USHIO INC. Was used as the polarized UV irradiation device.
-Olympus Corporation LEXT was used for the laser microscope.
-As the high-pressure mercury lamp, UNICURE VB-15201BY-A manufactured by USHIO INC. Was used.
The in-plane retardation value and the axial angle of the retardation layer / polarizing layer were measured using KOBRA-WPR manufactured by Oji Scientific Instruments.
The optical properties of the polarizing layer were measured using UV-3150 manufactured by Shimadzu Corporation.
The film thickness was measured using an ellipsometer M-220 manufactured by JASCO Corporation.

[Preparation of composition for forming alignment layers A and B]
A composition for forming alignment layers A and B is prepared by mixing 5 parts of a photoalignable material having the following structure and 95 parts of cyclopentanone (solvent) as components and stirring the resulting mixture at 80 ° C. for 1 hour. Got. In addition, the weight average molecular weight of the following photo-alignment material used for the alignment layer A is 30000, and the molecular weight of the following photo-alignment material used for the alignment film B is as shown in Table 1.

[Preparation of composition for forming retardation layer]
A polymerizable liquid crystal compound A having the following structure, a polyacrylate compound (leveling agent) (BYK-361N; manufactured by BYK-Chemie) and the following polymerization initiator are mixed as components to obtain a composition for forming a retardation layer. It was.
Polymerizable liquid crystal compound A

The polymerizable liquid crystal compound A was produced by the method described in JP 2010-31223 A. The amount of the polyacrylate compound was 0.01 parts with respect to 100 parts of the polymerizable liquid crystal compound A.
As a polymerization initiator, 2-dimethylamino-2-benzyl-1- (4-morpholinophenyl) butan-1-one (Irgacure 369 (Irg369); manufactured by BASF Japan Ltd.) with respect to 100 parts of the polymerizable liquid crystal compound A 6 parts were added.
Furthermore, N-methyl-2-pyrrolidone (NMP) was added as a solvent so that the solid content concentration was 13%, and the mixture was stirred at 80 ° C. for 1 hour to obtain a composition for forming a retardation layer.

(Preparation of composition for forming polarizing layer)
The following components were mixed and stirred at 80 ° C. for 1 hour to obtain a polarizing layer forming composition. As the dichroic dye, an azo dye described in Examples of JP2013-101328A was used. The polymerizable liquid crystal compounds represented by the formulas (1-6) and (1-7) were produced according to the method described in lub et al., Recl.Trav.Chim.Pays-Bas, 115, 321-328 (1996). .

Polymerizable liquid crystal compound:

75 copies

25 copies

Dichroic dye 1:
Polyazo dye; Compound (1-8) 2.5 parts

Compound (1-5) 2.5 parts

Compound (1-16) 2.5 parts

A polymerization initiator;
2-dimethylamino-2-benzyl-1- (4-morpholinophenyl) butan-1-one (Irgacure 369; manufactured by Ciba Specialty Chemicals) 6 parts leveling agent;
Polyacrylate compound (BYK-361N; manufactured by BYK-Chemie)
1.2 parts solvent; o-xylene 250 parts

[Example 1]
[Production of retardation layer]
A composition for forming alignment layer A is applied onto a COP film (ZF-14-50) manufactured by Nippon Zeon Co., Ltd., dried at 80 ° C. for 1 minute, and polarized UV irradiation apparatus (SPOT CURE SP-7; Polarized UV exposure was performed at an axial angle of 45 ° with an integrated light amount of 100 mJ / cm ² . When the film thickness of the obtained alignment layer A was measured with an ellipsometer, it was 100 nm.
Subsequently, the composition for forming a retardation layer prepared above was applied onto the alignment layer A using a bar coater, dried at 120 ° C. for 1 minute, and then a high-pressure mercury lamp (Unicure VB-15201BY-A, By using the Ushio Electric Co., Ltd.) and irradiating ultraviolet rays from the surface side coated with the composition of the retardation layer (accumulated light amount at a wavelength of 313 nm: 500 mJ / cm ² in a nitrogen atmosphere) A laminate including a phase difference layer was formed.
Subsequently, the laminate including the obtained retardation layer was processed once using a corona treatment apparatus (AGF-B10, manufactured by Kasuga Denki Co., Ltd.) under conditions of an output of 0.3 kW and a processing speed of 3 m / min. . On the surface subjected to corona treatment, the composition for forming the alignment layer B was applied with a bar coater, dried at 80 ° C. for 1 minute, and using a polarized UV irradiation apparatus (SPOT CURE SP-7; manufactured by USHIO INC.), Polarized UV exposure was carried out with an integrated light quantity of 100 mJ / cm ² and an axial angle of 90 °. It was 150 nm when the film thickness of the obtained alignment layer B was measured with the ellipsometer.
After applying the composition for forming a polarizing layer using a bar coater, it was dried in a drying oven set at 120 ° C. for 1 minute to obtain a dry coating film in which the polymerizable liquid crystal compound and the dichroic dye were aligned. The dried coating film is naturally cooled to room temperature, and then irradiated with ultraviolet rays using a high-pressure mercury lamp (Unicure VB-15201BY-A, manufactured by USHIO INC.) (In a nitrogen atmosphere, wavelength: 365 nm, integrated light quantity at wavelength 365 nm): 1000 mJ / cm ² ) to obtain an elliptically polarizing plate including a retardation layer and a polarizing layer, in which a polymerizable liquid crystal compound was polymerized to prepare a polarizing layer.

[Measurement of retardation value of elliptically polarizing plate]
When the in-plane retardation values of the obtained elliptically polarizing plate at a wavelength of 450 nm, a wavelength of 550 nm and a wavelength of 650 nm were measured, the retardation values at each wavelength were Re (450) = 116 nm, Re (550) = 140 nm, Re (650) = 144 nm, and the relationship between the in-plane retardation values is as follows.
Re (450) / Re (550) = 0.83
Re (650) / Re (550) = 1.03
(Where Re (450) is the in-plane retardation value for light having a wavelength of 450 nm, Re (550) is the in-plane retardation value for light having a wavelength of 550 nm, and Re (650) is the in-plane retardation value for light having a wavelength of 650 nm. Represents the phase difference value.)
That is, the retardation layer A had optical characteristics represented by the following formulas (1) to (3).
100 nm <Re (550) <160 nm (1)
Re (450) / Re (550) ≦ 1.0 (2)
1.00 ≦ Re (650) / Re (550) (3)
Further, the slow axis direction of the retardation layer was 45 °, and the absorption axis angle of the polarizing layer was 0 °. It is ideal that the angle formed by the retardation axis of the retardation plate and the absorption axis of the polarizing plate used in the circularly polarizing plate is 45 °, but the retardation layer of the produced elliptical polarizing plate is absorbed by the retardation axis and the polarizing layer. The angle formed by the axes was 45 °, and it was found that no axis deviation occurred.

[Measurement of polarization degree and single transmittance]
The degree of polarization and single transmittance of the obtained elliptically polarizing plate were measured as follows. The transmittance (T ¹ ) in the transmission axis direction and the transmittance (T ² ) in the absorption axis direction are doubled using a spectrophotometer (UV-3150, manufactured by Shimadzu Corporation) with a folder with a polarizer. Measurement was performed by a beam method in a wavelength range of 380 to 680 nm in 2 nm steps. Using the following formulas (p) and (q), the single transmittance and the degree of polarization at each wavelength are calculated, and the visibility is corrected by the 2 degree field of view (C light source) of JIS Z 8701. When the ratio (Ty) and the visibility corrected polarization degree (Py) were calculated, the single transmittance was 42% and the polarization degree was 97%, and it was confirmed that these were useful values as a polarizing plate.
Single transmittance (%) = (T ¹ + T ² ) / 2 (p)
Polarization degree (%) = {(T ¹ −T ² ) / (T ¹ + T ² )} × 100 (q)

[Refractive index of elliptically polarizing plate]
The refractive index of each layer was measured according to JIS K7142 using a refractometer (“Multi-wavelength Abbe refractometer DR-M4” manufactured by Atago Co., Ltd.).
Base material ... 1.53
Alignment film A 1.55
Retardation layer ... 1.62
Alignment film B 1.55
Polarizing layer ... 1.54

[Examples 2 to 6]
An elliptically polarizing plate is formed in the same manner as in Example 1 except that the thickness of the alignment layer B is adjusted by changing the thickness of the wire bar when the photo-orientation material is applied with a bar coater during the formation of the alignment layer B. Was made.

[Comparative Examples 1 and 2]
In the same manner as in Example 1 except that the thickness of the polarizing layer B was adjusted by changing the thickness of the wire bar when the photo-orientable material was applied with a bar coater when the alignment layer B was formed. A circularly polarizing plate including a polarizing layer was prepared.

[Correction 24.07.2017 under Rule 91]
Table 1 shows the results of measuring the optical characteristics of the polarizing layers described in the above-mentioned Examples and Comparative Examples.

The elliptically polarizing plate of the example could be manufactured without causing axial misalignment of the polarizing layer and occurrence of alignment defects.

Claims

An elliptically polarizing plate in which an alignment layer A, a retardation layer, an alignment layer B and a polarizing layer are provided in this order on a transparent substrate,
The optical axis of the polarizing layer and the retardation layer is not substantially parallel,
The retardation layer is a film composed of a polymer of a polymerizable liquid crystal compound,
The alignment layer B is a film having a thickness of 80 nm to 800 nm,
The polarizing layer is an elliptically polarizing plate in which a dichroic dye is aligned in a film composed of a polymer of a polymerizable liquid crystal compound.
The elliptically polarizing plate according to claim 1, wherein the transparent substrate, the alignment layer A, the retardation layer, the alignment layer B and the polarizing layer all have an average refractive index in the range of 1.4 to 1.7.
The elliptically polarizing plate according to claim 1 or 2, wherein the refractive index difference between adjacent layers is 0.2 or less.
The elliptically polarizing plate according to any one of claims 1 to 3, wherein an angle formed by an optical axis of the polarizing layer and the retardation layer is in a range of 40 ° to 50 °.
The elliptically polarizing plate according to any one of claims 1 to 4, wherein both the alignment layer A and the alignment layer B are photo-alignment films.
6. The elliptically polarizing plate according to claim 1, wherein the alignment layer A and the alignment layer B are photo-alignment films containing a cinnamoyl group.
The elliptically polarizing plate according to any one of claims 1 to 6, wherein the alignment layer A and the alignment layer B are photo-alignment films containing a resin having a weight average molecular weight of 20,000 to 50,000.
The elliptically polarizing plate according to any one of claims 1 to 7, wherein the polarizing layer is a film composed of a polymer in a smectic liquid crystal state.
The elliptically polarizing plate according to any one of claims 1 to 8, wherein the dichroic dye is an azo dye.
The elliptically polarizing plate according to any one of claims 1 to 9, wherein the retardation layer satisfies all of the following expressions.
100 nm <Re (550) <160 nm (1)
Re (450) / Re (550) ≦ 1.0 (2)
1.00 ≦ Re (650) / Re (550) (3)
(Re (450), Re (550), and Re (650) represent in-plane retardation at wavelengths of 450 nm, 550 nm, and 650 nm, respectively)
A liquid crystal display device comprising the elliptically polarizing plate according to any one of claims 1 to 10.
An organic EL display device comprising the elliptically polarizing plate according to any one of claims 1 to 11.
On the transparent substrate,
Applying a composition containing an alignment material A and a solvent, and irradiating polarized UV after drying to form an alignment layer A (1);
A step (2) of forming a retardation layer by applying a composition containing a polymerizable liquid crystal compound, a polymerization initiator and a solvent on the alignment layer A, followed by drying and polymerizing in a liquid crystal state by UV irradiation. ,
Applying a composition containing an alignment material B and a solvent, and irradiating polarized UV after drying to form the alignment layer B;
A step of forming a polarizing layer by applying a composition containing a polymerizable liquid crystal compound, a dichroic dye, a polymerization initiator, and a solvent on the alignment layer B, and drying and polymerizing in a liquid crystal state by UV irradiation. (4) and
The manufacturing method of the elliptically polarizing plate which has this.