WO2011138869A1

WO2011138869A1 - Optical element and method for improving viewing angle of polarizing film using same

Info

Publication number: WO2011138869A1
Application number: PCT/JP2011/002541
Authority: WO
Inventors: 悦幸矢作; 隼也野口; 良崇大橋; 雄一貞光; 義彦平良; 真由亀田; 興一田中
Original assignee: 日本化薬株式会社
Priority date: 2010-05-07
Filing date: 2011-05-02
Publication date: 2011-11-10
Also published as: JPWO2011138869A1; CN102884456A; CN102884456B; JP5973911B2; KR20130080789A; TW201200899A; TWI541529B

Abstract

Disclosed is an optical element which is formed of an optically anisotropic layer that contains organic dyes and has three-dimensional refractive indexes that satisfy nx > nz > ny with (nx - nz)/(nx - ny) being 0.2-0.7. The optical element is characterized in that at least one organic dye has a maximum absorption wavelength of 380 nm or more but less than 550 nm and at least one other organic dye has a maximum absorption wavelength of 550-780 nm (inclusive). The optical element has a function as a retardation element. In cases where a polarizing element comprising the optical element is used, black brightness can be uniformly suppressed low regardless of wavelength within the wavelength range of 450-700 nm, light leakage in an oblique direction is reduced, and leaked light is not colored or very little colored.

Description

Optical element and method for improving viewing angle of polarizing film using the same

The present invention relates to an optical element useful for an image display device such as a liquid crystal display device and a method for improving the viewing angle of a polarizing film using the same.

The polarizing film which is an essential member in the liquid crystal display device can be obtained, for example, as follows.
First, a polyvinyl alcohol film impregnated with a water-soluble dichroic dye or a dichroic dye such as polyiodine ion is uniaxially stretched in a boric acid warm aqueous solution, or the polyvinyl alcohol film is uniaxially stretched and then dehydrated. A polarizing element is obtained by forming a polyene structure by reaction. Next, the target polarizing plate can be obtained by sandwiching the polarizing element with an adhesive using a protective film such as a triacetyl cellulose film whose surface layer has been subjected to alkali treatment or a cycloolefin polymer.

However, when two such polarizing elements or polarizing films are used and the absorption axes are arranged so as to be orthogonal to each other, if the observation position is tilted in a direction different from the respective absorption axis directions from the front direction, the incident light is incident. There is a problem of the viewing angle dependency of the so-called polarizing element or polarizing film that the polarized light that has passed through the polarizing element or polarizing film on the side is not sufficiently absorbed by the output side polarizing plate and light leaks. This phenomenon has a particularly large influence on the viewing angle characteristics of a liquid crystal display device using various liquid crystal cells such as a vertical alignment (VA) type, an in-plane switching (IPS) type, and a bend nematic (OCB) type.

For such a problem, in Patent Document 1, by defining the optical constant of the retardation film, the influence of the liquid crystal layer and the optical compensation member in the oblique visual field is reduced, the black luminance in the oblique direction is improved, and the colored film is colored. A reduction method has been proposed. Non-Patent Document 1 discloses a method of reducing the viewing angle dependency of a polarizing film using two retardation plates.

However, the method of Patent Document 1 cannot sufficiently improve the viewing angle dependency. In addition, in the method of Non-Patent Document 1, colored light leaks because the wavelength dependency of the retardation film to be used can improve the viewing angle dependency of a specific wavelength but other wavelengths are insufficient. .
Although the wavelength dependency of the viewing angle improvement effect of the polarizing film can be effectively improved by the method as described in Patent Document 2 or Non-Patent Document 2, it is complicated that a plurality of films must be laminated. There is.

JP 2008-310064 A Japanese Patent No. 4137438

As described above, although there are various methods for improving the viewing angle dependency of the polarizing element or polarizing film, the wavelength dependency of the viewing angle improving effect and the complexity of using a plurality of films cannot be solved at the same time. Accordingly, an object of the present invention is to provide an optical element that improves the viewing angle dependency of the polarizing element or the polarizing film and also reduces the wavelength dependency without using a plurality of films.

The inventors of the present invention are optically anisotropic in which a three-dimensional refractive index containing at least two kinds of dichroic dyes is nx>nz> ny and an Nz coefficient is 0.2 to 0.7. It has been found that an optical element comprising a layer (retardation element) or a retardation film having the optical element on a transparent substrate is very useful for solving the above problems. In this specification, the Nz coefficient means a value of (nx−nz) / (nx−ny).
For example, by forming the optical element on a polarizing film, a polarizing film provided with the optical element is created, and the polarizing film with the optical element and a normal polarizing film are disposed between the polarizing elements. As described above, when the absorption axes of the two polarizing elements are arranged orthogonally, the above problem can be solved, that is, even if the observation position is inclined in a direction different from the respective absorption axis directions from the front direction, The present inventors have newly found that the viewing angle dependency of the polarizing film and the wavelength dependency of the viewing angle improvement effect can be greatly reduced without coloring the slight leaked light, and the present invention has been achieved. . That is, the present invention relates to the following inventions.

(1) It contains at least two kinds of organic dyes, the maximum refractive index in the plane is nx, the refractive index orthogonal to nx in the plane is ny, and the refractive index in the direction perpendicular to the plane is nz. An optical element comprising a colored and oriented optically anisotropic layer having a refractive index of nx>nz> ny and (nx−nz) / (nx−ny) of 0.2 to 0.7.
(2) The maximum absorption wavelength of at least one organic dye of the organic dye is 380 nm or more and less than 550 nm, and the maximum absorption wavelength of the other at least one organic dye is 550 nm or more and 780 nm or less (1) ) Optical element.
(3) The optical element according to (1) or (2), wherein the organic dye is an azo compound, an anthraquinone compound, a perylene compound, a quinophthalone compound, a naphthoquinone compound, or a merocyanine compound.
(4) The optical element according to any one of (1) to (3) above, wherein an in-plane retardation value of the optical anisotropic layer at a measurement wavelength of 550 nm is 130 nm to 300 nm.
(5) A retardation film having the optical element according to any one of (1) to (4) above.
(6) A composite retardation film obtained by laminating the optical element according to any one of (1) to (4) above or the retardation film according to (5) above and another retardation film.
(7) The composite retardation film as described in (6) above, wherein the other retardation film is a negative C plate or a positive C plate.
(8) An optical film obtained by laminating the optical element according to any one of (1) to (4) above and a polarizing film.
(9) An optical film obtained by laminating the retardation film according to (5) and a polarizing film.

(10) An optical film obtained by laminating the composite retardation film according to (6) or (7) above and a polarizing film.
(11) The optical film according to (8), wherein the optical film is laminated so that the slow axis of the optical element and the absorption axis of the polarizing film are orthogonal to each other.
(12) The optical film according to (9), wherein the retardation film is laminated so that the slow axis of the retardation film and the absorption axis of the polarizing film are orthogonal to each other.
(13) The optical element according to any one of (1) to (4), the retardation film according to (5), the composite retardation film according to (6) or (7), and the above (8) An image display device comprising at least one selected from the group consisting of the optical films according to any one of (12) to (12).
(14) The image display device according to (13), wherein the image display device is a liquid crystal display device.
(15) The optically anisotropic layer includes at least one of an organic dye having a maximum absorption wavelength of 380 nm to less than 550 nm and an organic dye having a maximum absorption wavelength of 550 nm to 780 nm, an oligophenyl compound, and the following general formula: The optical element according to the above (1), which is a layer formed from a composition comprising the compound represented by (A),

In the formula, X represents —O—CH 2 —ph—CH 2 —O—, —O—CO—ph—CO—O— or —NH—CO—ph—CO—NH—, and ph has sulfo substitution. Represents an optional paraphenylene group, and n represents the number of repetitions.

(16) As an organic dye having a maximum absorption wavelength of 380 nm or more and less than 550 nm,
The following general formula (B)

(Wherein X represents a sulfo group or a carboxy group, R ₁ and R ₂ each independently represent a hydrogen atom, a C1-C4 alkyl group, or a C1-C4 alkoxyl group, and n represents 1 or 2)
An azo compound represented by
Further, as an organic dye having a maximum absorption wavelength of 550 nm or more and 780 nm or less, the following general formula (C)

(Wherein Q ₂₁ is a naphthyl group having one or two sulfonic acid groups and further having a hydroxyl group or a C1-C4 alkoxy group, and Q ₂₂ and Q ₂₃ are each independently a phenylene group. Or a naphthylene group (these groups have one or two substituents selected from the group consisting of a C1-C4 alkyl group, a C1-C4 alkoxy group, a hydroxyl group and a sulfonic acid group as a substituent. R ₂₁ is a hydrogen atom, a C1-C4 alkyl group, an acetyl group, a benzoyl group or a substituted or unsubstituted phenyl group, R ₂₃ and R ₂₄ are each independently a hydrogen atom, a hydroxyl group, a sulfonic acid group, A C4 alkyl group or a C1-C4 alkoxy group, q represents 0 or 1, and r represents 1 or 2.)
Or a salt thereof,
The optical element according to (15), comprising:

The optical element of the present invention has a function of causing a phase difference and is useful as a phase difference element, and can be used as a phase difference film by providing the optical element on a transparent substrate film. In particular, the optical film having the optical element or the retardation film having the optical element on the polarizing film (hereinafter, also referred to as a polarizing film with an optical element) prevents light from leaking due to the inclination of the observation position in the liquid crystal display device. There is an effect that the viewing angle dependence of the polarizing film and the wavelength dependence of the viewing angle improvement effect can be greatly reduced without reducing and coloring even slight leaked light. That is, when the polarizing film with an optical element and a normal polarizing film are arranged with their absorption axes orthogonal to each other so that the optical elements are arranged between the polarizing elements, the respective absorption axis directions from the front direction Even if the observation position is tilted in a different direction, the omission of light is reduced, and even the slight leaked light is not colored, and the viewing angle dependence of the polarizing film and the wavelength dependence of the viewing angle improvement effect are also improved. It can be greatly reduced. Moreover, the viewing angle characteristic of a liquid crystal display can also be improved by using the polarizing film provided with this optical element for a liquid crystal display.

Bonding configuration diagram with polarizing film Bonding configuration diagram with polarizing film Bonding configuration diagram with polarizing film Black luminance measurement sample configuration diagram in diagonal direction Black luminance measurement sample configuration diagram in diagonal direction Illustration of diagonal measurement direction Graph of orthogonal transmittance waveform from polar angle 50 ° and azimuth angle 45 °

1. Polarizing film 1a. 1. Polarizing film 2. Optical anisotropic layer Absorption axis 4. Phase advance axis5. 6. Adhesive 7. Substrate 7. Releasable substrate 8. Glass plate9. Measurement sample 10. Azimuth θ
11. Polar angle φ
12 Front direction (θ, φ) = (0,0)
13. φ is 0-180 ° axis

Hereinafter, the present invention will be described in detail.
The optical element of the present invention comprises a biaxial layer defined below containing at least two kinds of organic dyes. The biaxiality referred to in the present invention means that the three-dimensional refractive index satisfies the relationship of nx>nz> ny and the Nz coefficient is 0.2 to 0.7, preferably 0.3 to 0.5. Means that. Here, nx is the maximum refractive index in the plane, ny is the refractive index orthogonal to nx in the plane, and nz represents the refractive index in the vertical direction with respect to the plane. Further, the Nz coefficient represents a value composed of (nx−nz) / (nx−ny). Outside this range, the effect of improving the viewing angle when applied to a liquid crystal display device may be poor, or coloring from an oblique direction may occur.
In order to show this biaxiality, a method of stretching a film and a method of applying a liquid crystal composition so as to be oriented and drying to form a coating film or a coating film layer (hereinafter referred to as an orientation coating film forming method) Say).
Examples of the method for stretching the film include the methods described in JP-A-2006-291192, WO2006 / 117981, and the like. Examples of the method for applying and aligning the liquid crystalline composition include the methods described in JP-T-2009-540345, W02010 / 020928, JP-A-2006-48078, JP-A-2006-316138, and the like. Is mentioned.

In the present invention, the latter method for forming an oriented coating film is preferred.
In the method of applying and aligning the liquid crystalline composition, a super-compound comprising at least one polycyclic organic compound having a conjugated π system and a functional group capable of forming a non-covalent bond between supramolecules. It is preferable to use a liquid crystalline composition exhibiting lyotropic liquid crystallinity composed of supuramolecule. Examples of such polycyclic organic compounds having lyotropic liquid crystallinity include oligophenyl compounds, bibenzimidazole compounds, acetonaphthoquinosaline compounds, and triazine compounds. Examples of oligophenyl compounds are shown in Table 1, and examples of bibenzimidazole compounds are shown in Table 2, respectively. Examples of acetonaphthoquinosaline compounds are shown in Table 3. Examples of triazine compounds are shown in Table 4.
In the present invention, among the compounds having the above lyotropic liquid crystallinity, an oligophenyl compound is preferable. Among the oligophenyl compounds, preferred compounds are a benzene ring, a biphenyl ring and a naphthalene ring via a 5- or 6-membered heterocyclic ring containing at least one hetero atom selected from the group consisting of an oxygen atom, a nitrogen atom and a sulfur atom. It is preferable that at least two rings selected from the group consisting of are bonded to each other, and the benzene ring, biphenyl ring or naphthalene ring preferably has one sulfo group.

For example, a compound represented by the following general formula (D) can be given as one preferred compound.

In the formula, Y ₁ represents —O—, —NH— or —SO ₂ —, Y ₂ represents a single bond, —O— or —NH—, A1 and A2 independently represent a benzene ring, a naphthalene ring or a biphenyl ring, The sulfo group (HSO ₃ ) is substituted on those rings.
Among these compounds, 4,4 '-(5,5'-dioxidedibenzo [b, d] thien-3,7-diyl) dibenzene sulfonic acid (4,4'-(5,5'-dioxidodibenzo [b, d] thiene-3,7-diyl) dibenzenesulfonic acid) is preferred.
The liquid crystalline composition containing such a compound is characterized by being aligned so as to satisfy the relationship of nx>nz> ny, for example, when an alignment treatment by shearing is performed.

In the present invention, a liquid crystal composition containing the above-mentioned liquid crystalline compound and an organic dye described later is formed on a substrate such as a film by forming a dry coating layer of the aligned liquid crystal composition on a substrate such as a film. And a substrate having an optical element composed of an optically anisotropic layer.
In addition to the compound or compounds exhibiting lyotropic liquid crystal properties, a polymer exhibiting liquid crystal properties may be added to the composition exhibiting lyotropic liquid crystal properties.
For example, there are rod-shaped liquid crystal polymers represented by WO2010 / 020928 (pages 16-17), and specific examples are shown in Table 5. It is preferable to add such a polymer exhibiting liquid crystallinity because the relationship between nx, ny, and nz of the obtained optical element can be adjusted and the durability can be improved.

Among the rod-like liquid crystalline polymers, compounds represented by the following general formula (A) are preferable.

Wherein X is —O—CH 2 —ph—CH 2 —O—, —O—CO—ph—CO—O— or —NH—CO—ph—CO—NH—, and ph has sulfo-substitution. N represents a repeating number.
The weight average molecular number of the liquid crystalline polymer is about 1,000 to 200,000, and preferably about 2,000 to 100,000. In some cases, the weight average molecular number may be about 3,000 to 70,000, or about 4,000 to 70,000.

The above-mentioned two or more organic dyes, a polycyclic organic compound having lyotropic liquid crystallinity, and preferably, the liquid crystalline composition containing the above liquid crystalline polymer usually contains a solvent for forming a coating solution. . The solvent used is not particularly limited as long as it has excellent solubility and exhibits lyotropic properties in a state where the solvent is dissolved in the composition. For example, water, alcohols, ethers, cellosolves, carboxylic acids And dimethyl sulfoxide. In the present invention, water is preferable from the viewpoint of handling. These can be used alone or as a mixture. A water-soluble solvent such as dimethylformamide, glycerin, or ethylene glycol may be added. These additives can be used to adjust the solubility or the drying rate of the aqueous solution.
The amount of the solvent is not particularly limited as long as it is a concentration at which the liquid crystalline composition can be applied. For example, in a liquid crystalline composition containing a solvent, the solid concentration is usually 5 to 50% by weight, preferably 8 to 30% by weight, based on the total amount of the composition.
Further, when the viscosity of the liquid crystalline composition is 200 to 1000 mPa · s when measured with an E-type viscometer at 25 ° C., it is suitable for producing a lyotropic liquid crystal. It is preferable to apply or apply a shearing force to the liquid crystal because the liquid crystal is aligned in a direction perpendicular to the MD direction.

Examples of at least two kinds of organic dyes used in the optical element of the present invention include azo compounds, anthraquinone compounds, perylene compounds, quinophthalone compounds, naphthoquinone compounds, merocyanine compounds, and the like. Even different types of dyes will not cause any problems. Usually, the same kind of compound is preferred. More preferably, it is an azo compound showing dichroism. For example, an azo compound described in “Application of Functional Dye” (supervised by Masahiro Irie, CMC Publishing) pages 98-100, C.I. I. Direct. Yellow 28, C.I. I. Direct. Yellow 44, C.I. I. Direct. Orange 26, C.I. I. Direct. Orange 107, C.I. I. Direct. Orange 71, C.I. I. Direct. Red2, C.I. I. Direct. Red31, C.I. I. Direct. Red 79, C.I. I. Direct. Red247, C.I. I. Direct. Green 80, C.I. I. Direct. Blue 202, C.I. I. Direct. Black 17, C.I. I. Direct. Blue 83, C.I. I. Direct. Orange 39, C.I. I. Direct. Red 79, C.I. I. Direct. Red 81, C.I. I. Direct. Yellow 12, C.I. I. Direct. Blue67, C.I. I. Direct. Red 39, C.I. I. Acid. Red 37, C.I. I. Direct. Green 59, C.I. I. Direct. Orange 72, C.I. I. Direct. Red 89, C.I. I. Direct. Red 83, C.I. I. Direct. Violet 48, C.I. I. Direct. Blue90, JP 2001-33627 A, JP 2002-296417 A, JP 2003-215338 A, WO 2004/092822, JP 2001-0564112 A, JP 2001-027708 A, Special Organic dyes and the like described in Kaihei 11-218611, JP-A-11-218610, JP-A-60-156759, JP-A-2001-33627, JP-A-2622748 and JP-A-3963379 Can be mentioned.

The at least two organic dyes used for forming the optical element or the retardation film of the present invention preferably have at least one organic dye having a maximum absorption wavelength of 380 nm or more and less than 550 nm, and the other at least one organic dye. The maximum absorption wavelength is 550 nm or more and 780 nm or less. More preferably, the maximum absorption wavelength of at least one organic dye (first dye) of the organic dye is 430 nm or more and 470 nm or less, and the maximum absorption wavelength of the other at least one organic dye (second dye) is 570 nm or more. It is 630 nm or less. Examples of the first dye include C.I. I. Direct. Orange 39, C.I. I. Direct. Orange 71, C.I. I. Direct. Orange 26, C.I. I. Direct. Examples thereof include organic dyes described in Orange 107 and WO 2007/138980.
Among these, an azo compound represented by the following general formula (B) or a salt thereof is preferable.

In the formula, X represents a sulfo group or a carboxy group, R ₁ and R ₂ each independently represent a hydrogen atom, a C1-C4 alkyl group, or a C1-C4 alkoxyl group, and n represents 1 or 2.

Examples of the second dye include C.I. I. Direct. Blue 202, C.I. I. Direct. Black 17, C.I. I. Direct. Blue 83, Direct. Examples thereof include organic dyes described in Green 51, Japanese Patent Application Laid-Open No. 2001-33627, and Japanese Patent No. 3963979 (0022-0027).
Preferred examples of the dye include a compound represented by the following general formula (C) or a salt thereof.

In the formula, Q ₂₁ represents one or two sulfonic acid groups, and further represents a naphthyl group optionally having a hydroxyl group or a C1-C4 alkoxy group, Q ₂₂ and Q ₂₃ are each independently a phenylene group or A naphthylene group (these groups have one or two substituents selected from a C1 to C4 alkyl group, a C1 to C4 alkoxy group, a hydroxyl group and a sulfonic acid group as a substituent), R ₂₁ is a hydrogen atom, a C1-C4 alkyl group, an acetyl group, a benzoyl group or a substituted or unsubstituted phenyl group, and R ₂₃ and R ₂₄ are each independently a hydrogen atom, a hydroxyl group, a sulfonic acid group, a C1-C4 alkyl group, or A C1-C4 alkoxy group, q represents 0 or 1, and r represents 1 or 2.

Thus, by including two or more kinds of dyes having different maximum absorption wavelengths, the optical element of the present invention exhibits a remarkably excellent effect. For example, when a polarizing film provided with the optical element of the present invention and a normal polarizing film are arranged with their absorption axes orthogonal to each other so that the optical element is arranged between the polarizing elements, each from the front direction Even if the observation position is tilted in a direction different from the absorption axis direction, the light omission is reduced and the viewing angle dependency of the polarizing film and the effect of improving the viewing angle are reduced without coloring the slight leaked light. Wavelength dependence can also be greatly reduced.

The total concentration of the above organic dyes is added to such an extent that the transmittance is not significantly reduced. Preferably, the content is 0.01 to 10% by weight, preferably 0.1 to 5% by weight, more preferably 0.1 to 3% by weight, based on the total amount of the solid content of the coating liquid. The ratio of the first dye and the second dye can be selected as appropriate. The amount of the second dye is 0.1 to 10 parts by weight, preferably 0. The ratio is 2 to 5 parts by weight, more preferably 0.5 to 2 parts by weight, and most preferably 0.7 to 1.5 parts by weight.

When the optical element of the present invention is used as a retardation film, a liquid crystalline composition comprising the polycyclic organic compound having lyotropic liquid crystallinity and an organic dye, preferably a liquid crystalline composition further comprising the liquid crystalline polymer. A phase difference film can be obtained by applying an object to a transparent substrate and orienting it to form an optically anisotropic layer on the substrate. Alternatively, a liquid crystal composition may be directly applied to a polarizing film to directly form an optically anisotropic layer oriented on the polarizing film, and a polarizing film including the optical element of the present invention may be used. In some cases, the oriented optical anisotropic layer may be first formed on a transfer substrate (releasing substrate), and the optical anisotropic layer may be transferred onto a polarizing film.
Preferably, the optically anisotropic layer is formed by being oriented in a direction perpendicular to the MD direction (Machine Direction) of the polarizing plate. The application method is not particularly limited as long as it can be uniformly applied and oriented. Applying to equipment using an appropriate coater such as slide coater, slot die coater, bar coater, rod coater, roll coater, curtain coater, spray coater, lip die coater, vacuum die coater, gravure coater, reverse gravure coater, micro gravure coater, etc. There is a method of spreading on a metal drum. Preferably, die coaters or gravure coaters are used, and in the case of gravure coaters, the use of a smoothing roll is also effective. There is no particular limitation on the drying means, and natural drying, vacuum drying, heat drying, vacuum heat drying and the like are used. As the heating and drying means, a drying method using an arbitrary drying apparatus such as an air circulation type drying oven or a hot roll is used. A preferable drying method is a method of drying at a low temperature of 0 ° C. to 40 ° C. and a relative humidity of 60% or less.

As the substrate used for the retardation film of the present invention, a transparent plastic substrate or glass is usually used, and a plastic substrate is preferable. Examples of the plastic substrate used in the present invention include acrylic resin, polycarbonate resin, epoxy resin, and cellulose resin. For example, triacetyl cellulose (TAC), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and syndiotactic. Tic polystyrene (SPS), polyphenylene sulfide (PPS), polycarbonate (PC), polyacrylate (PAr), polysulfone (PSF), polyester sulfone (PES), polyetherimide (PEI), cyclic polyolefin, polyimide (PI), etc. Can be mentioned. TAC is preferred. The thickness of the substrate is not particularly limited except for the application, but is generally in the range of 1 μm to 1000 μm. The surface of each film is preferably subjected to surface treatment such as corona treatment, plasma treatment, alkali treatment, and primer treatment in order to adjust the wettability of the composition used in the present invention.

The optically anisotropic layer or retardation film of the present invention has an in-plane retardation value of 130 to 300 nm at a measurement wavelength of 550 nm. The thickness is preferably 150 to 270 nm, more preferably 180 to 250 nm. The thickness of the optically anisotropic layer depends on various optical parameters such as the type of the liquid crystal cell and the in-plane retardation value, but cannot generally be said, but is usually 0.1 to 10 μm. Further, it is preferably 0.1 to 2 μm.

The optically anisotropic layer can be subjected to a treatment for improving water resistance after film formation. For example, a method of substituting with a group insoluble or hardly soluble in water using a lake agent. As the rake agent, metal ^ions such as Ni ²⁺ , Ca ²⁺ , Fe ³⁺ , Cu ²⁺ , Zn ²⁺ , Al ³⁺ , Pd ²⁺ , Cd ²⁺ , Pb ²⁺ , Sn ²⁺ , Co ²⁺ , Mn ²⁺ , Ba ²⁺ , and Ce ³⁺ Or a salt of an organic amine. These rake agents may be used alone or in combination of two or more in any ratio and combination.

Another method is to provide a protective layer on the optically anisotropic layer. The material used for the protective layer is not particularly limited, and examples thereof include a urethane resin, an epoxy resin, and an acrylic resin, and these may be used alone or in combination of two or more. A hydrophobic material is preferred, and a polyurethane resin is more preferred. A polyurethane resin excellent in flexibility can be laminated on the optical anisotropic layer without disturbing the orientation state of the optical anisotropic layer.

The method of using the chelating agent and the method of providing a protective layer can be performed in combination.
In the retardation film of the present invention, an optical anisotropic layer can be laminated on a substrate in order to obtain a desired characteristic value. In this case, the water resistance treatment using a chelating agent and / or the water resistance treatment for providing a protective layer may be performed for each layer or after all the optical anisotropic layers are laminated.

The optical element or retardation film of the present invention is used in combination with a polarizing film or other retardation film. Preferably, as shown in FIG. 1, the optical element or the retardation film 2 is laminated so that the slow axis 4 of the retardation film 2 and the absorption axis 3 of the polarizing film 1 are orthogonal to each other. In order to laminate, the optically anisotropic layer 2 is formed by directly applying to the polarizing film 1 as shown in FIG.
As shown in FIG. 2, the optical anisotropic layer side of the retardation film in which the optical anisotropic layer 2 is formed on the substrate is laminated with the polarizing film 1 or another retardation film via the acrylic adhesive 5.
Alternatively, the optically anisotropic layer 2 formed on the base material 7 as shown in FIG. 3 is bonded to the polarizing film 1 or another retardation film via an acrylic adhesive, and the base material 7 is peeled off, so that the optically anisotropic layer 2 The side layer 2 may be transferred to the polarizing film 1 or another retardation film.
The retardation film of the present invention can be used by being laminated with other retardation films, and for example, it can be used in combination with a negative C plate or a positive C plate.

Any polarizing film that is usually used can be used as the polarizing film used in the production of the polarizing film with an optical element of the present invention. The polarizing element (polarizer) used in the polarizing film is not particularly limited as long as it is an element having a function of polarizing light from a light source and absorbs light in a specific direction to be polarized. Any reflective polarizing element that reflects light in a specific direction to be polarized can be used. As an absorptive polarizing element, for example, a polarizing element obtained by uniaxially stretching a hydrophilic polymer film such as a polyvinyl alcohol film containing a dichroic dye such as a dye or polyvalent iodine ion, a polyvinyl alcohol film A polarizing element obtained by dehydrating with an acid before and after uniaxial stretching to form a polyene structure, and a solution of a dichroic dye that develops a lyotropic liquid crystal state on an alignment film that has been processed to align in a certain direction Examples thereof include a polarizing element obtained by applying and then removing the solvent. On the other hand, as a reflective polarizing element, for example, a polarizing element composed of a large number of laminated bodies having different birefringence, a polarizing element formed by combining a cholesteric liquid crystal having a selective reflection region and a quarter wavelength plate, and a substrate Examples thereof include a polarizing element provided with a fine wire grid. In order to obtain the effect of the present invention more effectively, a hydrophilic polymer such as a polyvinyl alcohol film containing a dichroic dye such as a dye or polyvalent iodine ion, which is excellent in polarization characteristics as a polarizing element. It is preferable to use a polarizing element obtained by uniaxially stretching a film, or a polarizing element obtained by forming a polyene structure by dehydration with an acid before and after uniaxial stretching of a polyvinyl alcohol film.

The polarizing element can be manufactured by a conventional method. For example, in the case of a polarizing element comprising a polyvinyl alcohol film containing a dichroic dye such as a dye and polyvalent iodine ions, the polyvinyl alcohol film was first swollen with warm water and then the dichroic dye was dissolved. The polarizing element can be obtained by immersing in a dyeing tank, dyeing the film, then stretching in a uniaxial direction in a tank containing a crosslinking agent such as boric acid or borax and drying. Examples of the dye used for dyeing include iodine-potassium iodide aqueous solution, “Application of functional dye” (supervised by Masahiro Irie, CMC Publishing Co., Ltd.), pages 98-100, C.I. I. Direct. Yellow 12, C.I. I. Direct. Yellow 28, C.I. I. Direct. Yellow 44, C.I. I. Direct. Orange 26, C.I. I. Direct. Orange 39, C.I. I. Direct. Orange 107, C.I. I. Direct. Red2, C.I. I. Direct. Red31, C.I. I. Direct. Red 79, C.I. I. Direct. Red 81, C.I. I. Direct. Red247, C.I. I. Direct. Green 80, C.I. I. Direct. Green 59, and JP 2001-33627, JP 2002-296417, JP 2003-215338, WO 2004/092822, JP 2001-0564112, JP 2001-027708, JP 11-218611, JP 11-218610, Examples thereof include organic dyes described in JP-A-60-156759, JP-A-2001-33627, and JP-A-2622748. These dichroic dyes are free acids, alkali metal salts (for example, Na salts, K salts and Li salts), ammonium salts, salts of amines, or complex salts (for example, Cu complexes, Ni complexes and Co complexes). Etc. The performance of the polarizing element can be adjusted by the dichroism of the dichroic dye, the stretch ratio during stretching, and the like.

An optically anisotropic layer (optical element) of the present invention or a retardation film of the present invention, or a composite retardation film obtained by laminating the optically anisotropic layer (optical element) or the retardation film and another retardation film. The image display device of the present invention, for example, a liquid crystal display device can be obtained by disposing it in combination with a polarizing plate in the light path of the image display device, for example, at least one side of the liquid crystal cell of the liquid crystal display device. The liquid crystal display device has various modes depending on the type of the liquid crystal cell to be used. In any case, a polarizing film provided with the optical anisotropic layer (optical element) of the present invention can be used. For example, VA (vertical alignment), IPS (in-plane switching), OCB (optically compensated bend), TN (twisted nematic), STN (super twisted nematic), etc. The retardation film of the present invention can be used in the apparatus. What is necessary is just to adjust the _NZ coefficient and retardation value of an optically anisotropic layer (optical element) or each retardation film according to each viewing angle characteristic.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited by these.
In the blending examples and examples, “part” means “part by weight” and “%” means “% by weight”.

Formulation Example 1
13.6 parts of the following compound described in JP-T-2009-540345,

2.4 parts of the following compound described in WO2010 / 020928,

84 parts of water, and 0.08 part of organic dye (CI Direct. Orange 39) described in WO2007 / 138980 and 0.08 part of organic dye described in Japanese Patent No. 3963979,

Were mixed and dissolved to prepare a solution having a solid content of about 16%. The viscosity of the solution was 330 mPa · s as measured by an E-type viscometer at 25 ° C.

Formulation Example 2
In the above Formulation Example 1, in place of 0.08 part of the organic dye described in Japanese Patent No. 3963799, C.I. I. Direct. A solution having a solid content of about 16% was prepared in the same manner as in Formulation Example 1 except that 0.08 part of Blue67 was used. The viscosity of the solution was 330 mPa · s as measured by an E-type viscometer at 25 ° C.

Formulation Example 3
In the above Formulation Example 1, the organic dye C.I. I. Direct. A solution having a solid content of about 16% was prepared in the same manner as in Formulation Example 1 except that the blending of both of the organic dyes described in Orange 39 and Japanese Patent No. 3963379 was stopped. The viscosity of the solution was 330 mPa · s as measured by an E-type viscometer at 25 ° C.

Formulation Example 4
In the above Formulation Example 1, C.I. I. Direct. A solution having a solid content of about 16% was prepared in the same manner as in Formulation Example 1 except that the blending of Orange 39 was stopped. The viscosity of the solution was 330 mPa · s as measured by an E-type viscometer at 25 ° C.

Example 1
The solution obtained in Formulation Example 1 was applied onto iodine-based polarizing plate 1a (trade name: SKN, manufactured by Polatechno Co., Ltd.) so that the thickness after drying was 1.0 μm, and a wire bar (# 10) was used. A shear stress was applied in the MD direction, and the compressor air was sprayed and dried. Further, a 10% barium nitrate aqueous solution was sprayed onto the coated surface by spraying, and compressed air was sprayed again to form an optically anisotropic layer, thereby producing a polarizing film with an optical element (optical film) of the present invention.

Example 2
Using the solution prepared in Formulation Example 2 instead of the solution prepared in Formulation Example 1, a polarizing film with an optical element (optical film) of the present invention was produced in the same manner as in Example 1.

Example 3
The solution prepared in Formulation Example 1 was applied onto a triacetylcellulose (TAC) film whose surface was alkali-treated so that the thickness after drying was 1.0 μm, and the wire bar (# 10) was used in the MD direction. Shear stress was applied, and compressor air was sprayed to dry. Further, a 10% barium nitrate aqueous solution was sprayed onto the coated surface by spraying, and compressed air was sprayed again to dry, thereby producing a retardation film having an optically anisotropic layer on the film. The TAC film surface of the retardation film and the iodine-based polarizing plate 1a (trade name: SKN, manufactured by Polatechno Co., Ltd.) are used. The acrylic adhesive 5 (product) (Name: PTR-2500, manufactured by Nippon Kayaku Co., Ltd.).

Comparative Example 1
The iodine type polarizing plate 1a (trade name: SKN, manufactured by Polatechno Co., Ltd.) having no optically anisotropic layer used in Example 1 was used as it was.

Comparative Example 2
Using the solution prepared in Formulation Example 3 instead of the solution prepared in Formulation Example 1, the same operation as in Example 1 was performed to obtain a polarizing film having a comparative optically anisotropic layer.

Comparative Example 3
Using the solution prepared in Formulation Example 4 instead of the solution prepared in Formulation Example 1, the same operation as in Example 1 was performed to obtain a polarizing film having a comparative optically anisotropic layer.

The nx, nz, ny and Nz coefficients of each optical anisotropic layer obtained above were as follows.
nx ny nz NZ factor Example 1 1.81 1.60 1.73 0.38
Example 2 1.80 1.60 1.73 0.35
Example 3 1.81 1.60 1.73 0.38
Comparative Example 1 (no optical anisotropic layer)
Comparative Example 2 1.80 1.59 1.73 0.33
Comparative Example 3 1.80 1.60 1.73 0.35

The in-plane retardation value at the measurement wavelength of 550 nm in the optically anisotropic layer was as follows.
Example 1 205nm
Example 2 205 nm
Example 3 215 nm
Comparative Example 1 (no optical anisotropic layer)
Comparative Example 2 195 nm
Comparative Example 3 200nm

<Optical characteristics: Black luminance in oblique direction>
As shown in FIG. 4, the optical anisotropic layer side 2 of the optical film (polarizing film with an optical element of the present invention) on which the optical anisotropic layer obtained in Examples 1 and 2 and Example 3 is formed is an acrylic adhesive. 5 (trade name: PTR-2500, manufactured by Nippon Kayaku Co., Ltd.) was attached to one side of the glass plate 8. An iodine polarizing plate 1a (trade name: SKN, manufactured by Polatechno Co., Ltd.) is also applied to the opposite side of the glass plate 8 via an acrylic adhesive 5 (trade name: PTR-2500, manufactured by Nippon Kayaku Co., Ltd.). A laminated sample (optical system) for optical property test was prepared by arranging the plates 1a (trade name: SKN, manufactured by Polatechno Co., Ltd.) so that their absorption axes are orthogonal to each other. In the same manner for Comparative Examples 1 to 3, laminated samples (optical systems) for optical property tests were prepared.

As shown in FIG. 6, the laminated sample having the above configuration is measured from a polar angle of 0 °, an azimuth angle of 0 °, a polar angle of 50 °, and an azimuth angle of 45 °, and the visibility corrected orthogonal transmittances Yc (0,0) and Yc (50 45). The transmittance was measured using a spectrophotometer (U-4100, manufactured by Hitachi Spectroscopic Co., Ltd.). The black luminance in the oblique direction is better as the Yc value is smaller. FIG. 7 shows orthogonal transmittance waveforms for Example 1 and Comparative Examples 1 and 2. The results for Examples 1 to 3 and Comparative Examples 1 to 3 are shown in Table 6.
In the case of using the liquid crystal panel provided with the optical element of the present invention, as is clear from FIG. 7, the orthogonal transmittance is uniformly low at a wavelength of about 450 to 700 nm regardless of the wavelength, and as can be seen from Table 6. Further, it can be seen that the black luminance Yc value in the oblique direction is low, and there is no or very little coloration in the oblique direction.

<Optical characteristics: Colored diagonally>
Remove the liquid crystal panel from the liquid crystal display device [LCD manufactured by Hitachi, Ltd., trade name “Wooo]” including the liquid crystal cell in IPS mode, and remove part of the optical film placed on the backlight side of the liquid crystal cell. The glass surface (front and back) of the liquid crystal cell was washed. The optical anisotropic layer side 2 of the film obtained by forming the optical anisotropic layer obtained in Examples 1 to 3 on the backlight side of the liquid crystal cell was attached to the acrylic adhesive 5 (trade name: PTR-2500, Japan). Pasted through Kayaku Co., Ltd.). In the bonding, the slow axis of the optically anisotropic layer and the retardation film and the long side direction of the panel were made parallel. Thereby, the absorption axis of the polarizing plate (trade name: SKN, manufactured by Polatechno Co., Ltd.) of the film formed with the optical anisotropic layer obtained in Example 1 and Example 2 bonded to the backlight side, The absorption axis of the surface-side polarizing plate of the cell is orthogonal. The obtained liquid crystal panel was used for the test. In addition, in the same manner for Comparative Examples 1 to 3, test liquid crystal panels were prepared.

The obtained test liquid crystal panel was placed on a backlight to obtain a liquid crystal display device. After the black screen was displayed on the liquid crystal display device and the backlight was turned on in the dark room, after 30 minutes had elapsed, the degree of coloring was observed visually from an oblique direction (azimuth angle 45 °, polar angle 50 °). The observation results for Examples 1 to 3 and Comparative Examples 1 to 3 are shown in Table 6.

◎: Not colored ○: Slightly colored △: Colored ×: Largely colored
The evaluation results are shown in Table 1 below.

(Table 6)
Yc (0,0) Yc (50,45) Colored evaluation example 1 in an oblique direction 0.01% 0.20% A
Example 2 0.01% 0.27% ○
Example 3 0.01% 0.21%
Comparative Example 1 0.01% 0.47% ×
Comparative Example 2 0.01% 0.30%
Comparative Example 3 0.01% 0.28%

By using the optical film provided with the optical element of the present invention, the orthogonal transmittance can be kept low uniformly regardless of the wavelength in a wavelength range of about 450 to 700 nm without using a large number of retardation films. I can do it. Further, the black luminance in the oblique direction can be suppressed to a low level, and coloring in the oblique direction can be eliminated or significantly reduced, so that it is extremely useful as an optical element.

Claims

When it contains at least two kinds of organic dyes, the maximum refractive index in the plane is nx, the refractive index orthogonal to nx in the plane is ny, and the refractive index in the direction perpendicular to the plane is nz, the three-dimensional refractive index is An optical element comprising a colored and oriented optically anisotropic layer in which nx> nz> ny and (nx−nz) / (nx−ny) is 0.2 to 0.7.
The maximum absorption wavelength of at least one organic dye of the organic dye is 380 nm or more and less than 550 nm, and the maximum absorption wavelength of the other at least one organic dye is 550 nm or more and 780 nm or less. Optical element.
The optical element according to claim 1, wherein the organic dye is an azo compound, an anthraquinone compound, a perylene compound, a quinophthalone compound, a naphthoquinone compound, or a merocyanine compound.
2. The optical element according to claim 1, wherein an in-plane retardation value of the optical anisotropic layer at a measurement wavelength of 550 nm is 130 nm to 300 nm.
A retardation film having the optical element according to claim 1.
A composite retardation film obtained by laminating the optical element according to claim 1 or 4 or the retardation film according to claim 5 and another retardation film.
The other retardation film is a negative C plate or a positive C plate, The composite retardation film according to claim 6.
An optical film obtained by laminating the optical element according to any one of claims 1 to 4 and a polarizing film.
An optical film formed by laminating the retardation film according to claim 5 and a polarizing film.
An optical film formed by laminating the composite retardation film according to claim 6 and a polarizing film.
The optical film according to claim 8, wherein the optical film is laminated so that the slow axis of the optical element and the absorption axis of the polarizing film are orthogonal to each other.
The optical film according to claim 9, wherein the retardation film is laminated so that the slow axis of the retardation film and the absorption axis of the polarizing film are orthogonal to each other.
The optical element according to any one of claims 1 to 45, the retardation film according to claim 5, the composite retardation film according to claim 6 or 7, and any one of claims 8 to 12. An image display device comprising at least one selected from the group consisting of the described optical films.
The image display device according to claim 13, wherein the image display device is a liquid crystal display device.
The optically anisotropic layer includes at least one organic dye having a maximum absorption wavelength of 380 nm to less than 550 nm and one of an organic dye having a maximum absorption wavelength of 550 nm to 780 nm, an oligophenyl compound, and the following general formula (A): The optical element according to claim 1, which is a layer formed from a composition comprising a compound represented by:

In the formula, X represents —O—CH 2 —ph—CH 2 —O—, —O—CO—ph—CO—O— or —NH—CO—ph—CO—NH—, and ph has sulfo substitution. Represents an optional paraphenylene group, and n represents the number of repetitions.
As an organic dye having a maximum absorption wavelength of 380 nm or more and less than 550 nm,
The following general formula (B)

(Wherein X represents a sulfo group or a carboxy group, R 1 and R 2 each independently represent a hydrogen atom, a C1-C4 alkyl group, or a C1-C4 alkoxyl group, and n represents 1 or 2)
An azo compound represented by
Further, as an organic dye having a maximum absorption wavelength of 550 nm or more and 780 nm or less, the following general formula (C)

(Wherein Q 21 is a naphthyl group having one or two sulfonic acid groups and further having a hydroxyl group or a C1-C4 alkoxy group, and Q 22 and Q 23 are each independently a phenylene group. Or a naphthylene group (these groups have one or two substituents selected from the group consisting of a C1-C4 alkyl group, a C1-C4 alkoxy group, a hydroxyl group and a sulfonic acid group as a substituent. R 21 is a hydrogen atom, a C1-C4 alkyl group, an acetyl group, a benzoyl group or a substituted or unsubstituted phenyl group, R 23 and R 24 are each independently a hydrogen atom, a hydroxyl group, a sulfonic acid group, A C4 alkyl group or a C1-C4 alkoxy group, q represents 0 or 1, and r represents 1 or 2.)
Or a salt thereof,
The optical element according to claim 15.