TWI767015B - Optically anisotropic layer and method for producing the same, optically anisotropic stack, multilayer for transfer, polarizing plate, and image display device - Google Patents

Abstract

An optically anisotropic layer, which is an optically anisotropic layer comprising a positive type C polymer, a polymer of a mesogen compound. The aforementioned mesogen compound is a compound having a mesogen skeleton and an acrylate structure. The aforementioned optically anisotropic layer satisfies 0.073<A _{C − H} /A _{C = O} (mesogen compound)<0.125. A _{C - H} is the infrared absorption related to the out-of-plane bending vibration of the C-H bond of the acrylate structure in the infrared absorption spectrum of the optically anisotropic layer, A _{C = O} (mesogen compound) is In the infrared absorption spectrum of the optically anisotropic layer, the infrared absorption related to the stretching vibration of the C=O bond of the acrylate structure and the C=O bond derived from the C=O bond of the acrylate structure The sum of the infrared absorption associated with the stretching vibration of the knot. Manufacture of an optically anisotropic layer and its use.

Description

Optically anisotropic layer and method for producing the same, optically anisotropic stack, multilayer for transfer, polarizing plate, and image display device

The present invention relates to an optically anisotropic layer and a method for producing the same; an optically anisotropic stack including the optically anisotropic layer; and a transfer multilayer, polarizing plate, and image display device including the optically anisotropic layer .

Various optical films are provided in image display devices such as liquid crystal display devices and organic electroluminescence display devices. Hereinafter, "organic electroluminescence" will be referred to as "organic EL" as appropriate. The technology of such an optical film has been studied in the past (for example, Patent Documents 1 and 2).

"Patent Document" "Patent Document 1": Japanese Patent Publication No. 2015-14712 "Patent Document 2": Japanese Patent Publication No. 2015-57646 (corresponding publication: US Patent Application Publication No. 2015/041051)

A circular polarizer is arranged on the display surface of the image display device. As the circularly polarizing plate, an optical film including a linear polarizer and an optically anisotropic layer is generally used. Since the circular polarizing plate is arranged on the display surface of the image display device, the reflection of external light can be suppressed when the display surface is viewed from the front direction, so that the light for displaying the image can penetrate the polarized sunglasses, so the visibility of the image can be improved. sex.

The effect of the above-mentioned circular polarizer may be damaged when the display surface is viewed from an oblique direction. In order to improve the effect of viewing the display surface from an oblique direction, a combination of a positive type C film and a circular polarizer is considered. The positive-type C film used for such an application is preferably a film that exhibits reverse wavelength dispersion in the retardation Rth in the thickness direction. Such a positive type C thin film can be considered to be produced by a production method using a liquid crystal compound as described in Patent Documents 1 and 2, for example.

However, in the conventional technique, it is not easy to manufacture a positive type C thin film in which the retardation Rth in the thickness direction exhibits reverse wavelength dispersion. For example, in the method of using an alignment film like the production methods using a liquid crystal compound described in Patent Documents 1 and 2, adjustment of the compatibility between the alignment film and the liquid crystal compound is required, and the adjustment is complicated. Furthermore, since the process of coating an alignment film on a base material increases, the use of an alignment film may lead to the possibility of raising cost. In addition, various properties other than wavelength dispersion properties are also required for optical films used in image display devices. For example, high durability and good hue are required for optical films. The conventional positive-type C thin film having reverse wavelength dispersion Rth may deteriorate in terms of such durability and color tone. For example, when optical films are generally required to reduce the deterioration caused by prolonged use in a high temperature environment, the conventional positive type C film with reverse wavelength dispersion Rth used in a high temperature environment for a long time is prone to Defects such as increased haze and cloudiness occur. In addition, when the optical film is generally required to have no deviation in transmittance and reflectance due to the wavelength of light and the color tone is close to colorless, the positive C film with reverse wavelength dispersion Rth in the prior art still has a color tone that is not colorless. And the case with yellow and other hues.

Therefore, an object of the present invention is to provide an optically anisotropic layer that "can be produced without using an alignment film, has a positive C plate exhibiting reverse wavelength dispersion in retardation Rth in the thickness direction, has high durability, and has a good color tone" And the multilayer for transfer including the aforementioned optically anisotropic layer, a method for producing the same, and an optically anisotropic stack including the optically anisotropic layer, the multilayer for transfer, a polarizing plate, and an image display device.

The present invention is as follows.

[1] An optically anisotropic layer comprising a positive-type C polymer, a mesogen compound, and a polymer of a mesogen compound, wherein the positive-type C polymer is obtained by using When the film of the positive C polymer is formed by the coating method of the solution of the positive C polymer, the film satisfies the polymer of formula (1), and the mesogen compound is a compound having a mesogen skeleton and an acrylate structure , the aforementioned optically anisotropic layer satisfies formula (2) and formula (3): nz(P)>nx(P)≧ny(P) formula (1) nz(A)>nx(A)≧ny(A) Formula (2) 0.073<A _{C - H} /A _{C = O} (mesogen compound)<0.125 Formula (3) where nx(P), ny(P) and nz(P) are the principal refractive indices of the film, nx(A), ny(A) and nz(A) are the principal refractive indices of the optically anisotropic layer, and A _{C - H} are the above-mentioned mesogen compounds in the infrared absorption spectrum of the optically anisotropic layer. The infrared absorption related to the out-of-plane bending vibration of the C-H bond possessed by the acrylate structure, A _{C = O} (the mesogen compound) is in the infrared absorption spectrum of the optically anisotropic layer, the aforementioned mesogen compound Infrared absorption related to the stretching vibration of the C=O bond possessed by the acrylate structure and infrared absorption related to the stretching vibration of the C=O bond of the C=O bond possessed by the aforementioned mesogen compound sum of absorption.

[2] The optically anisotropic layer according to [1], wherein the mesogen compound is a compound that exhibits in-plane retardation of reverse wavelength dispersion in the case of uniform alignment.

[3] The optically anisotropic layer according to [1] or [2], which satisfies Formula (4) and Formula (5): 0.50<Rth(A450)/Rth(A550)<1.00 Formula (4) 1.00 ≦Rth(A650)/Rth(A550)<1.25 Formula (5) Wherein, Rth(A450) is the retardation of the optically anisotropic layer in the thickness direction at a wavelength of 450 nm, Rth(A550) is the optically anisotropic layer The retardation in the thickness direction at a wavelength of 550 nm, Rth(A650) is the retardation in the thickness direction at a wavelength of 650 nm of the aforementioned optically anisotropic layer.

（在前述式（I）中： Y¹ ～Y⁸ 分別獨立表示化學上的單鍵、－O－、－S－、－O－C(＝O)－、－C(＝O)－O－、－O－C(＝O)－O－、－NR¹ －C(＝O)－、－C(＝O)－NR¹ －、－O－C(＝O)－NR¹ －、－NR¹ －C(＝O)－O－、－NR¹ －C(＝O)－NR¹ －、－O－NR¹ －或－NR¹ －O－；於此，R¹ 表示氫原子或碳數1～6之烷基； G¹ 及G² 分別獨立表示亦可具有取代基的碳數1～20之二價脂族基；並且，在前述脂族基中每一個脂族基亦可中介有一個以上的－O－、－S－、－O－C(＝O)－、－C(＝O)－O－、－O－C(＝O)－O－、－NR² －C(＝O)－、－C(＝O)－NR² －、－NR² －或－C(＝O)－；其中，排除二個以上之－O－或－S－分別鄰接而中介的情況；於此，R² 表示氫原子或碳數1～6之烷基； Z¹ 及Z² 分別獨立表示亦可由鹵素原子取代的碳數2～10之烯基； A^x 表示具有選自由芳烴環及芳雜環而成之群組的至少一個芳環的碳數2～30之有機基； A^y 表示氫原子、亦可具有取代基的碳數1～20之烷基、亦可具有取代基的碳數2～20之烯基、亦可具有取代基的碳數3～12之環烷基、亦可具有取代基的碳數2～20之炔基、－C(＝O)－R³ 、－SO₂ －R⁴ 、－C(＝S)NH－R⁹ 或具有選自由芳烴環及芳雜環而成之群組的至少一個芳環的碳數2～30之有機基；於此，R³ 表示亦可具有取代基的碳數1～20之烷基、亦可具有取代基的碳數2～20之烯基、亦可具有取代基的碳數3～12之環烷基或碳數5～12之芳烴環基；R⁴ 表示碳數1～20之烷基、碳數2～20之烯基、苯基或4-甲基苯基；R⁹ 表示亦可具有取代基的碳數1～20之烷基、亦可具有取代基的碳數2～20之烯基、亦可具有取代基的碳數3～12之環烷基或亦可具有取代基的碳數5～20之芳基；前述A^x 及A^y 所具有的芳環亦可具有取代基；並且，前述A^x 與A^y 亦可結伴形成環； A¹ 表示亦可具有取代基的三價芳基； A² 及A³ 分別獨立表示亦可具有取代基的碳數3～30之二價脂環烴基； A⁴ 及A⁵ 分別獨立表示亦可具有取代基的碳數6～30之二價芳基； Q¹ 表示氫原子或亦可具有取代基的碳數1～6之烷基； m及n分別獨立表示0或1； 其中，Z¹ －Y⁷ －及－Y⁸ －Z² 之其中一者或兩者為丙烯醯氧基）。[4] The optically anisotropic layer according to any one of [1] to [3], wherein the mesogen compound is represented by the following formula (I): "Chemical 1"

(In the aforementioned formula (I): Y ¹ to Y ⁸ each independently represent a chemical single bond, -O-, -S-, -O-C(=O)-, -C(=O)-O- , -O-C(=O)-O-, -NR ¹ -C(=O)-, -C(=O)-NR ¹ -, -O-C(=O)-NR ¹ -, -NR ¹ -C(=O)-O-, -NR ¹ -C(=O)-NR ¹ -, -O-NR ¹ - or -NR ¹ -O-; here, R ¹ represents a hydrogen atom or carbon number Alkyl of 1 to 6; G ¹ and G ² each independently represent a divalent aliphatic group with 1 to 20 carbon atoms that may also have a substituent; and, in the aforementioned aliphatic groups, each aliphatic group may also contain One or more of -O-, -S-, -O-C(=O)-, -C(=O)-O-, -O-C(=O)-O-, -NR ² -C(= O)-, -C(=O)-NR ² -, -NR ² - or -C(=O)-; wherein, the case where two or more -O- or -S- are adjacent to each other and intermediary is excluded; in Here, R ² represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms; Z ¹ and Z ² each independently represent an alkenyl group having 2 to 10 carbon atoms that may be substituted by a halogen atom; A ^x represents a group selected from an aromatic hydrocarbon ring and an aromatic hydrocarbon ring. Organic group with 2 to 30 carbon atoms of at least one aromatic ring of the group formed by heterocycles; A ^y represents a hydrogen atom, an alkyl group with 1 to 20 carbon atoms that may have a substituent, or a carbon that may have a substituent Alkenyl group having 2 to 20 carbon atoms, cycloalkyl group having 3 to 12 carbon atoms that may have a substituent, alkynyl group having 2 to 20 carbon atoms that may have a substituent group, -C(=O)-R ³ , - SO ₂ -R ⁴ , -C(=S)NH-R ⁹ or an organic group having at least one aromatic ring selected from the group consisting of an aromatic hydrocarbon ring and an aromatic heterocyclic ring and an organic group having 2 to 30 carbon atoms; here, R ³ represents an alkyl group with 1 to 20 carbon atoms that may have a substituent, an alkenyl group with 2 to 20 carbon atoms that may have a substituent, a cycloalkyl group with 3 to 12 carbon atoms that may have a substituent, or a cycloalkyl group with 3 to 12 carbon atoms that may have a substituent Aromatic hydrocarbon ring group of 5-12; R ⁴ represents an alkyl group with a carbon number of 1-20, an alkenyl group with a carbon number of 2-20, a phenyl group or a 4-methylphenyl group; R ⁹ represents a carbon number that can also have a substituent 1 to 20 alkyl groups, optionally substituted alkenyl groups with 2 to 20 carbon atoms, optionally substituted cycloalkyl groups with 3 to 12 carbon atoms, or optionally substituted with 5 to 20 carbon atoms Aryl group; the aromatic ring possessed by the aforementioned A ^x and A ^y may also have a substituent; and the aforementioned A ^x and A ^y may also be combined to form a ring; A ¹ represents a trivalent aryl group which may also have a substituent; A ² and A ³ each independently represent a divalent alicyclic hydrocarbon group with a carbon number of 3 to 30 that can also have a substituent; A ⁴ and A ⁵ each independently represent a divalent aryl group with a carbon number of 6 to 30 that can also have a substituent; Q ¹ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms which may have a substituent; m and n each independently represent 0 or 1; wherein, Z ¹ -Y ⁷ - and -Y ⁸ One or both of -Z ² is acryloxy).

[5] The optically anisotropic layer according to any one of [1] to [4], wherein the mesogen compound contains in its molecular structure a molecule selected from the group consisting of “benzothiazole ring” and “cyclohexyl ring and At least one of the group consisting of "a combination of benzene rings".

[6] The optically anisotropic layer according to any one of [1] to [5], wherein the positive type C polymer is selected from the group consisting of polyvinylcarbazole, polyfumarate, and cellulose-derived at least one polymer of the group consisting of.

[7] The optically anisotropic layer according to any one of [1] to [6], wherein the ratio of the mesogenic compound and the polymer thereof in the total solid content of the optically anisotropic layer is 20 wt. % or more and 60% by weight or less.

[8] The optically anisotropic layers described in [1] to [7], which satisfy the formulas (6) and (7): Re(A590)≦10 nm Formula (6)−200 nm≦Rth(A590 )≦－10 nm Formula (7) where Re(A590) is the in-plane retardation of the optically anisotropic layer at a wavelength of 590 nm, and Rth(A590) is the thickness direction of the optically anisotropic layer at a wavelength of 590 nm Delay.

[9] A multilayered article for transfer, comprising a base material and the optically anisotropic layer according to any one of [1] to [8].

[10] An optically anisotropic stack comprising the optically anisotropic layer and the retardation layer according to any one of [1] to [8], wherein the retardation layer satisfies the formula (8): nx( B)>ny(B)≧nz(B) Formula (8) wherein nx(B), ny(B) and nz(B) are the principal refractive indices of the retardation layer.

[11] The optically anisotropic stack according to [10], wherein the retardation layer satisfies the equations (9) and (10): 0.75<Re(B450)/Re(B550)<1.00 Equation (9) 1.01<Re(B650)/Re(B550)<1.25 Formula (10) where Re(B450) is the in-plane retardation of the aforementioned retardation layer at a wavelength of 450 nm, and Re(B550) is the aforementioned retardation layer at a wavelength of 550 nm. In-plane retardation, Re(B650) is the in-plane retardation of the aforementioned retardation layer at a wavelength of 650 nm.

（在前述式（II）中： Y¹ ～Y⁸ 分別獨立表示化學上的單鍵、－O－、－S－、－O－C(＝O)－、－C(＝O)－O－、－O－C(＝O)－O－、－NR¹ －C(＝O)－、－C(＝O)－NR¹ －、－O－C(＝O)－NR¹ －、－NR¹ －C(＝O)－O－、－NR¹ －C(＝O)－NR¹ －、－O－NR¹ －或－NR¹ －O－；於此，R¹ 表示氫原子或碳數1～6之烷基； G¹ 及G² 分別獨立表示亦可具有取代基的碳數1～20之二價脂族基；並且，在前述脂族基中每一個脂族基亦可中介有一個以上的－O－、－S－、－O－C(＝O)－、－C(＝O)－O－、－O－C(＝O)－O－、－NR² －C(＝O)－、－C(＝O)－NR² －、－NR² －或－C(＝O)－；其中，排除二個以上之－O－或－S－分別鄰接而中介的情況；於此，R² 表示氫原子或碳數1～6之烷基； Z¹ 及Z² 分別獨立表示亦可由鹵素原子取代的碳數2～10之烯基； A^x 表示具有選自由芳烴環及芳雜環而成之群組之至少一個芳環的碳數2～30之有機基； A^y 表示氫原子、亦可具有取代基的碳數1～20之烷基、亦可具有取代基的碳數2～20之烯基、亦可具有取代基的碳數3～12之環烷基、亦可具有取代基的碳數2～20之炔基、－C(＝O)－R³ 、－SO₂ －R⁴ 、－C(＝S)NH－R⁹ 或具有選自由芳烴環及芳雜環而成之群組之至少一個芳環的碳數2～30之有機基；於此，R³ 表示亦可具有取代基的碳數1～20之烷基、亦可具有取代基的碳數2～20之烯基、亦可具有取代基的碳數3～12之環烷基或碳數5～12之芳烴環基；R⁴ 表示碳數1～20之烷基、碳數2～20之烯基、苯基或4-甲基苯基；R⁹ 表示亦可具有取代基的碳數1～20之烷基、亦可具有取代基的碳數2～20之烯基、亦可具有取代基的碳數3～12之環烷基或亦可具有取代基的碳數5～20之芳基；前述A^x 及A^y 所具有的芳環亦可具有取代基；並且，前述A^x 與A^y 亦可結伴形成環； A¹ 表示亦可具有取代基的三價芳基； A² 及A³ 分別獨立表示亦可具有取代基的碳數3～30之二價脂環烴基； A⁴ 及A⁵ 分別獨立表示亦可具有取代基的碳數6～30之二價芳基； Q¹ 表示氫原子或亦可具有取代基的碳數1～6之烷基； m及n分別獨立表示0或1）。[12] The optically anisotropic stack according to [11], wherein the retardation layer comprises a liquid crystal compound for retardation layer represented by the following formula (II): "Chemical 2"

(In the aforementioned formula (II): Y ¹ to Y ⁸ each independently represent a chemical single bond, -O-, -S-, -O-C(=O)-, -C(=O)-O- , -O-C(=O)-O-, -NR ¹ -C(=O)-, -C(=O)-NR ¹ -, -O-C(=O)-NR ¹ -, -NR ¹ -C(=O)-O-, -NR ¹ -C(=O)-NR ¹ -, -O-NR ¹ - or -NR ¹ -O-; here, R ¹ represents a hydrogen atom or carbon number Alkyl of 1 to 6; G ¹ and G ² each independently represent a divalent aliphatic group with 1 to 20 carbon atoms that may also have a substituent; and, in the aforementioned aliphatic groups, each aliphatic group may also contain One or more of -O-, -S-, -O-C(=O)-, -C(=O)-O-, -O-C(=O)-O-, -NR ² -C(= O)-, -C(=O)-NR ² -, -NR ² - or -C(=O)-; wherein, the case where two or more -O- or -S- are adjacent to each other and intermediary is excluded; in Here, R ² represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms; Z ¹ and Z ² each independently represent an alkenyl group having 2 to 10 carbon atoms that may be substituted by a halogen atom; A ^x represents a group selected from an aromatic hydrocarbon ring and an aromatic hydrocarbon ring. Organic group with 2 to 30 carbon atoms of at least one aromatic ring of the group formed by heterocycles; A ^y represents a hydrogen atom, an alkyl group with 1 to 20 carbon atoms that may have a substituent, or a carbon that may have a substituent Alkenyl group having 2 to 20 carbon atoms, cycloalkyl group having 3 to 12 carbon atoms that may have a substituent, alkynyl group having 2 to 20 carbon atoms that may have a substituent group, -C(=O)-R ³ , - SO ₂ -R ⁴ , -C(=S)NH-R ⁹ or an organic group having at least one aromatic ring selected from the group consisting of an aromatic hydrocarbon ring and an aromatic heterocyclic ring and an organic group having 2 to 30 carbon atoms; here, R ³ represents an alkyl group with 1 to 20 carbon atoms that may have a substituent, an alkenyl group with 2 to 20 carbon atoms that may have a substituent, a cycloalkyl group with 3 to 12 carbon atoms that may have a substituent, or a cycloalkyl group with 3 to 12 carbon atoms that may have a substituent Aromatic hydrocarbon ring group of 5-12; R ⁴ represents an alkyl group with a carbon number of 1-20, an alkenyl group with a carbon number of 2-20, a phenyl group or a 4-methylphenyl group; R ⁹ represents a carbon number that can also have a substituent 1 to 20 alkyl groups, optionally substituted alkenyl groups with 2 to 20 carbon atoms, optionally substituted cycloalkyl groups with 3 to 12 carbon atoms, or optionally substituted with 5 to 20 carbon atoms Aryl group; the aromatic ring possessed by the aforementioned A ^x and A ^y may also have a substituent; and the aforementioned A ^x and A ^y may also be combined to form a ring; A ¹ represents a trivalent aryl group which may also have a substituent; A ² and A ³ each independently represent a divalent alicyclic hydrocarbon group with a carbon number of 3 to 30 that may have a substituent; A ⁴ and A ⁵ independently represent a divalent aryl group with a carbon number of 6 to 30 that may also have a substituent; Q ¹ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms which may have a substituent; m and n each independently represent 0 or 1).

[13] A polarizing plate comprising: a linear polarizer; and the optically anisotropic layer according to any one of [1] to [8], the multilayer for transfer according to [9], or the The optically anisotropic stack according to any one of [10] to [12].

[14] An image display device including the polarizing plate according to [13].

[15] An image display device, which sequentially includes: the optically anisotropic stack according to any one of [10] to [12]; a linear polarizer; and an image display element; the image display element is a liquid crystal cells or organic electroluminescent elements.

[16] A method for producing an optically anisotropic layer according to any one of [1] to [8], comprising: preparing a positive-type C polymer, a mesogen compound, a solvent, and a photopolymerization initiator and the process of coating liquid of crosslinking agent; the process of applying the coating liquid on the support surface to obtain a coating liquid layer; and the process of irradiating the coating liquid layer with light to cure the coating liquid layer.

[17] The method for producing an optically anisotropic layer according to [16], wherein in the coating solution, the ratio of the photopolymerization initiator to 100 parts by weight of the mesogen compound is 1 part by weight to 10 parts by weight parts, and the ratio of the crosslinking agent to 100 parts by weight of the mesogen compound is 1 part by weight to 10 parts by weight.

[18] The production method according to [16] or [17], wherein the integrated light amount of the irradiated light beam is 600 mJ/cm ² to 5000 mJ/cm ² .

According to the present invention, there is provided an optically anisotropic layer capable of producing a positive type C plate that exhibits reverse wavelength dispersion in the retardation Rth in the thickness direction, and has high durability and good color tone Multilayer for transfer of anisotropic layer, method for producing the same, and optically anisotropic stack including the optically anisotropic layer, multilayer for transfer, polarizing plate, and image display device.

Embodiments and examples are disclosed below to describe the present invention in detail. However, the present invention is not limited to the embodiments and examples shown below, and can be modified and implemented arbitrarily without departing from the scope of the claims of the present invention and its equivalents.

In the following description, unless otherwise noted, the front direction of a surface means the normal direction of the surface, and specifically refers to the direction in which the polar angle of the surface is 0° and the azimuth angle is 0°.

In the following description, the so-called inclination direction of a certain surface, unless otherwise noted, means the direction that is neither parallel nor perpendicular to the surface, specifically refers to the direction in the range where the polar angle of the aforementioned surface is greater than 0° and less than 90° .

In the following description, unless otherwise noted, the in-plane retardation Re of a layer is a value represented by Re=(nx-ny)×d, and the retardation Rth in the thickness direction of a layer is defined by Rth = The value represented by {[(nx+ny)/2]-nz}×d. Here, nx represents the refractive index of the direction which belongs to the in-plane direction of the layer body and which gives the maximum refractive index, ny represents the refractive index of the direction which belongs to the in-plane direction of the layer body and is orthogonal to the nx direction, and nz represents the refractive index of the layer body. The refractive index in the thickness direction, d represents the thickness of the layer. In addition, the in-plane direction refers to a direction perpendicular to the thickness direction.

In the following description, unless otherwise noted, the refractive index is measured at a wavelength of 590 nm.

In the following description, the so-called "long-shaped" member refers to a member having a length that is usually 5 times or more relative to the width, preferably 10 times or more in length. The length of a roll to store or transport it". The upper limit of the length of the elongated member is not particularly limited, but is set to be, for example, 100,000 times or less the width.

In the following description, "polarizing plate" and "wavelength plate" include not only rigid members but also flexible members such as resin films.

In the following description, unless otherwise noted, "(meth)acrylic acid" is a term that includes "acrylic acid", "methacrylic acid", and combinations thereof.

In the following description, the directions of the so-called requirements are "parallel" and "perpendicular", and unless otherwise noted, errors within a range of ±5°, for example, may be included within a range that does not impair the effects of the present invention.

In the following description, a resin having a positive intrinsic birefringence value means a resin whose refractive index in the extending direction is larger than the refractive index in the direction orthogonal to this. In addition, a resin having a negative intrinsic birefringence value means a resin whose refractive index in the extending direction is smaller than the refractive index in the direction perpendicular to the direction. The intrinsic birefringence value is calculated from the Dielectric constant distribution.

In the following description, the so-called principal refractive index of a certain layer or film means the refractive index nx belonging to the in-plane direction of the layer and the direction giving the maximum refractive index, the in-plane direction of the layer and perpendicular to the direction of "giving the maximum refractive index". The refractive index ny in the direction of the aforementioned nx, and the refractive index nz in the thickness direction of the layer. In this application, the indices of refraction corresponding to these nx, ny and nz are represented by symbols including the strings "nx", "ny" and "nz", respectively. For example, among the principal refractive indices nx(A), ny(A) and nz(A) of the optically anisotropic layer, nx(A) belongs to the in-plane direction of the optically anisotropic layer and gives the maximum refractive index The refractive index in the direction, ny(A) is the refractive index in the in-plane direction of the optically anisotropic layer and is perpendicular to the direction "giving nx(A)", nz(A) is the refractive index of the optically anisotropic layer Refractive index in the thickness direction.

In the following description, the expression that the in-plane retardation Re of a layer exhibits reverse wavelength dispersion means that the in-plane retardation Re(450) and Re(550) of the layer at wavelengths of 450 nm and 550 nm satisfy Re(450)/ Re(550)<1.00. Re has a layer with reverse wavelength dispersion, preferably the layer has retardation Re(550) and Re(650) in the plane at wavelengths of 550 nm and 650 nm and further satisfies Re(550)/Re(650)<1.00.

The so-called retardation Rth in the thickness direction of a layer refers to the inverse wavelength dispersion, which means that the retardation Rth(450) and Rth(550) of the layer in the thickness direction at wavelengths of 450 nm and 550 nm satisfy Rth(450)/Rth( 550) < 1.00. A layer with reverse wavelength dispersion in Rth, preferably the retardation Rth(550) and Rth(650) of the layer in the thickness direction at wavelengths of 550 nm and 650 nm further satisfy Rth(550)/Rth(650)<1.00 .

[1. Optically anisotropic layer]

The optically anisotropic layer of the present invention comprises a positive type C polymer, a mesogen compound and a polymer of a mesogen compound, and has specific optical properties.

[1.1. Positive C polymer]

The positive type C polymer is a polymer, and when a film of the polymer is formed by a coating method using a solution of the polymer, the film satisfies the formula (1). nz(P)>nx(P)≧ny(P) Formula (1) where nx(P), ny(P) and nz(P) are the principal refractive indices of the film. By using such a positive type C polymer in combination with a mesogen compound, it is possible to realize an optical system that "can be produced without using an alignment film, and can be used as a positive type C plate that exhibits reverse wavelength dispersion in retardation Rth in the thickness direction". Anisotropic layer.

Whether or not a certain polymer corresponds to a positive type C polymer can be confirmed by the following method.

First, a polymer as a sample is added to methyl ethyl ketone (MEK), 1,3-dioxoquinone, N-methylpyrrolidone ( NMP) and other solvents, which were dissolved at room temperature to obtain a polymer solution.

This polymer solution was applied on an unstretched film made of resin using an applicator to form a layer of the polymer solution. After that, the solvent was evaporated by drying in an oven at 85° C. for about 10 minutes to obtain a polymer film having a thickness of about 10 μm.

Then, it is evaluated whether the refractive index nx(P), the refractive index ny(P), and the refractive index nz(P) of the polymer film satisfy the formula (1). Conforms to positive type C polymers.

The values of the refractive index nx(P) and the refractive index ny(P) are preferably the same or close to each other. Specifically, the difference nx(P)-ny(P) between the refractive index nx(P) and the refractive index ny(P) is preferably 0.00000 to 0.00100, preferably 0.00000 to 0.00050, and particularly preferably 0.00000 to 0.00020 . When the refractive index difference nx(P)-ny(P) falls within the aforementioned range, the optically anisotropic layer of the present invention can be easily obtained.

As the positive type C polymer, when a film of the positive type C polymer is formed by a coating method using the solution of the positive type C polymer, "this film has a refractive index satisfying the aforementioned formula (1)" can be used. of any polymer. Among them, as the positive type C polymer, at least one polymer selected from the group consisting of "polyvinylcarbazole, polyfumarate and cellulose derivatives" is preferable. By using these polymers as the positive type C polymer, an optically anisotropic layer having a large retardation Rth in the thickness direction can be easily obtained by coating.

As an example of polyvinylcarbazole, the polymer containing the polymerized unit which superposed|polymerized 9-vinylcarbazole is mentioned.

Examples of polyfumarate include: a copolymer of diisopropyl fumarate and 3-ethyl-3-oxomethyl acrylate; and di-fumarate Copolymer of isopropyl ester and cinnamic acid ester.

The positive type C polymer may be used alone or in combination of two or more in any ratio.

The proportion of the positive type C polymer in the total solid content of the optically anisotropic layer is preferably 30% by weight or more, more preferably 35% by weight or more, more preferably 40% by weight or more, and 60% by weight or less More preferably, it is 55% by weight or less, more preferably 50% by weight or less. By making the ratio of the positive type C polymer more than the lower limit of the aforementioned range, the mesogen compound can be uniformly dispersed in the optically anisotropic layer, and the mechanical strength of the optically anisotropic layer can be improved, and by the aforementioned Below the upper limit of the range, the wavelength dispersion of retardation Rth in the thickness direction of the optically anisotropic layer can be easily brought close to the inverse dispersion. Here, the so-called solid content of a certain layer refers to a component that remains when the layer is dried.

[1.2. Mesogen compound]

In the present application, the mesogen compound is a compound having a mesogen skeleton and an acrylate structure.

The mesogen skeleton of a mesogen compound means a molecular skeleton that essentially contributes to the generation of a liquid crystal phase in a low-molecular-weight or high-molecular-weight substance due to the anisotropy of the interaction of attraction and repulsion. The mesogen compound containing the mesogen skeleton itself may not necessarily have liquid crystallinity such that phase transition to the liquid crystal phase occurs. Therefore, the mesogen compound may be a liquid crystal compound that undergoes phase transition to a liquid crystal phase in a single state, or a non-liquid crystal compound that does not undergo phase transition to a liquid crystal phase in a single state. Examples of the mesogen skeleton include rigid rod-shaped or disc-shaped cells. For the mesogen skeleton, refer to: Pure Appl.Chem.2001, Vol. 73 (No. 5), p. 888 and C.Tschierske, G.Pelzl, S.Diele, Angew.Chem.2004, Vol.116, 6340-6368 Page.

In the optically anisotropic layer, the mesogen compound can also fix the alignment state thereof. For example, the mesogen compound can also be polymerized to fix the alignment state of the mesogen compound. Since the mesogen compound is usually polymerized to maintain the alignment state of the mesogen compound to become a polymer, the alignment state of the mesogen compound is fixed by the aforementioned polymerization. Therefore, the term "the mesogen compound in which the alignment state is fixed" includes the polymer of the mesogen compound. Therefore, when the mesogen compound is a liquid crystal compound having liquid crystallinity, the liquid crystal compound may exhibit a liquid crystal phase in the optically anisotropic layer, or may not exhibit a liquid crystal phase by being immobilized in an alignment state.

As the aforementioned mesogen compound, a reverse wavelength dispersion liquid crystal compound, a reverse wavelength mesogen compound, or a combination of these can be used.

Here, the reverse wavelength dispersion liquid crystal compound means a compound that satisfies all of the following requirements (i) and (ii). (i) The reverse wavelength dispersion liquid crystal compound exhibits liquid crystallinity. (ii) The reverse wavelength dispersive liquid crystal compound exhibits reverse wavelength dispersive in-plane retardation with uniform alignment.

In addition, the reverse wavelength mesogen compound means a compound that satisfies all of the following requirements (iii), requirements (iv), and requirements (v). (iii) The reverse wavelength mesogen compound does not exhibit liquid crystallinity in a single state. (iv) The specific mixture for evaluation containing a reverse wavelength mesogen compound expresses liquid crystallinity. (v) In the case where the aforementioned mixture for evaluation is uniformly aligned, the reverse wavelength mesogen compound exhibits reverse wavelength dispersive in-plane retardation.

The aforementioned mixture for evaluation refers to "mixing the aforementioned reverse wavelength mesogen compound in a ratio of at least any one of 30 parts by weight to 70 parts by weight relative to 100 parts by weight of the liquid crystal compound for evaluation and the reverse wavelength mesogen compound in total. A mixture of liquid crystal compounds for evaluation of in-plane retardation exhibiting forward wavelength dispersibility in the case of uniform alignment.

By using such a mesogen compound in combination with a positive type C polymer, it is possible to realize an optical system that "can be produced without using an alignment film, and can be used as a positive type C plate that exhibits reverse wavelength dispersion in retardation Rth in the thickness direction". Anisotropic layer.

The reverse wavelength dispersion liquid crystal compound will be described below.

The reverse wavelength dispersive liquid crystal compound exhibits reverse wavelength dispersive in-plane retardation in the case of uniform alignment. Herein, uniformly aligning the liquid crystal compound means forming a layer containing the liquid crystal compound, and aligning the long axis direction of the mesogen skeleton of the molecules of the liquid crystal compound in the layer in a direction parallel to the plane of the layer. a certain direction. In the case where the liquid crystal compound contains a plurality of mesogen skeletons having different alignment directions, the direction in which the mesogen of the longest type among these is aligned is set as the aforementioned alignment direction. Whether the liquid crystal compound is uniformly aligned and its alignment direction can be determined by "measurement in the slow axis direction using a phase difference meter such as AxoScan (manufactured by Axometrics), and the retardation distribution at each incident angle in the slow axis direction. Measure" to confirm.

In the case where a liquid crystal layer containing a reverse wavelength dispersion liquid crystal compound is formed, and the long axis direction of the mesogen skeleton of the molecules of the liquid crystal compound in the layer is aligned in a direction parallel to the surface of the liquid crystal layer, the liquid crystal The in-plane retardations Re(L450) and Re(L550) of the layers in wavelengths of 450 nm and 550 nm generally satisfy Re(L450)/Re(L550)<1.00.

Furthermore, the in-plane retardation Re(L450), Re(L550) and Re(L650) of the aforementioned liquid crystal layer in the wavelengths of 450 nm, 550 nm and 650 nm make the desired effect of the present invention more well exhibited. From a viewpoint, it is preferable to satisfy Re(L450)<Re(L550)≦Re(L650).

As the reverse wavelength dispersion liquid crystal compound, for example, a compound containing a main chain mesogen skeleton and a side chain mesogen skeleton bonded to the main chain mesogen skeleton in the molecule of the reverse wavelength dispersion liquid crystal compound can be used. The aforementioned reverse wavelength dispersion liquid crystal compound comprising a main chain mesogen skeleton and a side chain mesogen skeleton, in the state where the reverse wavelength dispersion liquid crystal compound is aligned, the side chain mesogen skeleton is aligned in a direction different from that of the main chain mesogen skeleton direction. In this case, the birefringence is exhibited as the difference between the "refractive index corresponding to the main chain mesogen skeleton" and the "refractive index corresponding to the side chain mesogen skeleton", so as a result, the reverse wavelength dispersion liquid crystal compound is uniformly aligned in the In this case, in-plane retardation with reverse wavelength dispersion can be exhibited.

For example, like the aforementioned compounds having a main chain mesogen skeleton and a side chain mesogen skeleton, the reverse wavelength dispersion liquid crystal compound usually has a specific steric shape different from that of the general cis wavelength dispersion liquid crystal compound. Here, the "sequential wavelength dispersive liquid crystal compound" refers to a liquid crystal compound that exhibits an in-plane retardation with a forward wavelength dispersion property under the condition of uniform alignment. In addition, the so-called in-plane retardation of forward wavelength dispersion means that the larger the measurement wavelength, the smaller the in-plane retardation. The fact that the reverse wavelength dispersion liquid crystal compound has such a specific steric shape is presumed to be a factor for obtaining the effects of the present invention.

The CN point of the reverse wavelength dispersion liquid crystal compound is preferably 25°C or higher, preferably 45°C or higher, more preferably 60°C or higher, and preferably 120°C or lower, preferably 110°C or lower, and 100°C or lower. ℃ or lower is particularly preferred. The "CN point" as used herein refers to the crystal-nematic transition temperature. The optically anisotropic layer can be easily produced by using the reverse wavelength dispersion liquid crystal compound having the CN point in the aforementioned range.

The molecular weight of the reverse wavelength dispersive liquid crystal compound, when it is a monomer, is preferably 300 or more, preferably 700 or more, more preferably 1000 or more, and preferably 2000 or less, preferably 1700 or less, 1500 or less is especially preferred. Since the reverse wavelength dispersion liquid crystal compound has the molecular weight as described above, the coatability of the coating liquid for forming the optically anisotropic layer can be optimized in particular.

The aforementioned reverse wavelength dispersion liquid crystal compounds may be used alone or in combination of two or more in any ratio.

As an inverse wavelength dispersion liquid crystal compound, the thing described in Unexamined-Japanese-Patent No. 2014-123134 is mentioned, for example. Moreover, as a reverse wavelength dispersion liquid crystal compound, the compound which expresses liquid crystallinity among the compounds represented by following formula (Ia) is mentioned, for example. In the following description, the compound represented by the formula (Ia) will be referred to as "compound (Ia)" as appropriate.

"Hua 3"

In the aforementioned formula (Ia), A ^1a represents: an aromatic hydrocarbon ring group having "an organic group having at least one aromatic ring selected from the group consisting of an aromatic hydrocarbon ring and an aromatic heterocyclic ring having 1 to 67 carbon atoms" as a substituent; Or an aromatic heterocyclic group having "an organic group having at least one aromatic ring selected from the group consisting of an aromatic hydrocarbon ring and an aromatic heterocyclic ring having 1 to 67 carbon atoms" as a substituent.

As a specific example of A ^1a , it is possible to enumerate: by the formula: -R ^f C[=N-N(R ^g )R ^h ] or by the formula: -R ^f C[=N-N=C(R ^g1 ) The group represented by R ^h ]” substituted phenylene; 1-benzofuran-2-yl substituted benzothiazole-4,7-diyl; 5-(2-butyl)-1-benzene benzothiazole-4,7-diyl substituted with furan-2-yl; benzothiazole-4,7-diyl substituted with 4,6-dimethyl-1-benzofuran-2-yl; benzothiazole-4,7-diyl substituted with 6-methyl-1-benzofuran-2-yl; substituted with 4,6,7-trimethyl-1-benzofuran-2-yl benzothiazole-4,7-diyl; benzothiazole-4,7-diyl substituted with 4,5,6-trimethyl-1-benzofuran-2-yl; 5-methyl- 1-benzofuran-2-yl substituted benzothiazole-4,7-diyl; 5-propyl-1-benzofuran-2-yl substituted benzothiazole-4,7-diyl; 7-propyl-1-benzofuran-2-yl substituted benzothiazole-4,7-diyl; 5-fluoro-1-benzofuran-2-yl substituted benzothiazole-4, 7-diyl; phenyl-substituted benzothiazole-4,7-diyl; 4-fluorophenyl-substituted benzothiazole-4,7-diyl; 4-nitrophenyl-substituted benzene benzothiazole-4,7-diyl; benzothiazole-4,7-diyl substituted with 4-trifluoromethylphenyl; benzothiazole-4,7-diyl substituted with 4-cyanophenyl ; benzothiazole-4,7-diyl substituted with 4-methanesulfonylphenyl; benzothiazole-4,7-diyl substituted with thiophen-2-yl; benzene substituted with thiophen-3-yl Thiazol-4,7-diyl; benzothiazole-4,7-diyl substituted with 5-methylthiophen-2-yl; benzothiazole-4,7 substituted with 5-chlorothiophen-2-yl -diyl; benzothiazole-4,7-diyl substituted with thiophen[3,2-b]thiophen-2-yl; benzothiazole-4,7-diyl substituted with 2-benzothiazolyl ; 4-biphenyl substituted benzothiazole-4,7-diyl; 4-propylbiphenyl substituted benzothiazole-4,7-diyl; 4-thiazolyl substituted benzo Thiazole-4,7-diyl; benzothiazole-4,7-diyl substituted with 1-phenylethen-2-yl; benzothiazole-4,7-diyl substituted with 4-pyridyl; benzothiazole-4,7-diyl substituted with 2-furyl; benzothiazole-4,7-diyl substituted with naphthalene[1,2-b]furan-2-yl; 5-methoxy 1H-isoindole-1,3(2H)-dione-4,7-diyl substituted with phenyl-2-benzothiazolyl; 1H-isoindole-1,3(2H) substituted with phenyl -Diketo-4,7-diyl; 1H-isoindole-1,3(2H)-dione-4,7-diyl substituted with 4-nitrophenyl; or substituted with 2-thiazolyl 1H-isoindole-1,3(2H)-dione-4,7-diyl; etc. Here, R ^f represents the same meaning as Q ¹ described later. R ^g and R ^g1 each independently represent the same meaning as A ^y described later, and R ^h represents the same meaning as A ^x described later.

In the aforementioned formula (Ia), Y ^1a to Y ^8a each independently represent a chemical single bond, -O-, -S-, -O-C(=O)-, -C(=O)-O-, -O-C(=O)-O-,-NR1 ^- C(=O)-,-C(=O) ^-NR1 -,-O-C(=O) ^-NR1 -, ^- NR1 -C(=O)-O-, ^{-NR1 -} C(=O)-NR1-, -O-NR1-, or ^{-NR1 -} O-. Here, R ¹ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

In the aforementioned formula (Ia), G ^1a and G ^2a each independently represent a divalent aliphatic group having 1 to 20 carbon atoms which may have a substituent. In addition, each aliphatic group on the aforementioned aliphatic group may have at least one -O-, -S-, -O-C(=O)-, -C(=O)-O-, -O- interposed. C(=O)-O-, -NR ² -C(=O)-, -C(=O)-NR ² -, -NR ² - or -C(=O)-. Among them, the case where two or more -O- or -S- are adjacent to each other and intermediary is excluded. Here, R ² represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

In the aforementioned formula (Ia), Z ^1a and Z ^2a each independently represent an alkenyl group having 2 to 10 carbon atoms which may be substituted by a halogen atom.

In the aforementioned formula (Ia), A ^2a and A ^3a each independently represent a divalent alicyclic hydrocarbon group having 3 to 30 carbon atoms which may have a substituent.

In the aforementioned formula (Ia), A ^4a and A ^5a each independently represent a divalent aryl group having 6 to 30 carbon atoms which may have a substituent.

In the aforementioned formula (Ia), k and l each independently represent 0 or 1.

However, in the aforementioned formula (Ia), one or both of Z ^1a -Y ^7a - and -Y ^8a -Z ^2a is acryloxy.

As a particularly suitable specific example of the reverse wavelength dispersion liquid crystal compound, a compound which exhibits liquid crystallinity among the compounds represented by the following formula (I) can be mentioned. In the following description, the compound represented by formula (I) will be referred to as "compound (I)" as appropriate.

"Hua 4"

Compound (I), usually, as represented by the following formula, contains "a radical-Y ⁵ -A ⁴ -Y ³ -(A ² -Y ¹ ) _n -A ¹ -(Y ² -A ³ ) _m -Y Main chain mesogen skeleton 1a formed by ⁴ -A ⁵ -Y ⁶ -" and "side chain mesogen skeleton 1b formed by group>A ¹ -C(Q ¹ )=N-N(A ^x )A ^y " of the two mesogen skeletons. And these main chain mesogen skeletons 1a and side chain mesogen skeletons 1b intersect with each other. Although the main chain mesogen skeleton 1a and the side chain mesogen skeleton 1b can also be combined to form one mesogen skeleton, in the present invention, two mesogen skeletons are marked.

"Hua 5"

The refractive index of the main chain mesogen skeleton 1a in the long axis direction is defined as n1, and the refractive index of the side chain mesogen skeleton 1b in the long axis direction is defined as n2. At this time, the absolute value and wavelength dispersion of the refractive index n1 generally depend on the molecular structure of the main chain mesogen skeleton 1a. In addition, the absolute value and wavelength dispersion of the refractive index n2 generally depend on the molecular structure of the side chain mesogen skeleton 1b. Here, the compound (I) in the liquid crystal phase usually rotates with the long axis direction of the main chain mesogen skeleton 1a as the rotation axis, so the refractive indices n1 and n2 referred to here represent the refraction as a rotating body Rate.

Due to the molecular structures of the main chain mesogen skeleton 1a and the side chain mesogen skeleton 1b, the absolute value of the refractive index n1 is larger than the absolute value of the refractive index n2. Furthermore, the refractive indices n1 and n2 generally exhibit forward wavelength dispersion. Here, the so-called forward-wavelength dispersive refractive index means that the larger the measurement wavelength, the smaller the absolute value of the refractive index. The refractive index n1 of the main chain mesogen skeleton 1a exhibits a small degree of forward wavelength dispersion. Therefore, the refractive index n1 measured at the long wavelength is smaller than the refractive index measured at the short wavelength, but the difference is small. On the other hand, the refractive index n2 of the side chain mesogen skeleton 1b exhibits a large degree of forward wavelength dispersion. Therefore, the refractive index n2 measured at a long wavelength is smaller than the refractive index n2 measured at a short wavelength, and the difference is large. Therefore, when the measurement wavelength is short, the difference Δn between the refractive index n1 and the refractive index n2 is small, and when the measurement wavelength is long, the difference Δn between the refractive index n1 and the refractive index n2 is large. In this way, due to the main chain mesogen skeleton 1a and the side chain mesogen skeleton 1b, the compound (I) exhibits the in-plane retardation of reverse wavelength dispersion property in the case of uniform alignment.

In the aforementioned formula (I), Y ¹ to Y ⁸ each independently represent a chemical single bond, -O-, -S-, -O-C(=O)-, -C(=O)-O-, -O-C(=O)-O-,-NR1 ^- C(=O)-,-C(=O) ^-NR1 -,-O-C(=O) ^-NR1 -, ^- NR1 -C(=O)-O-, ^{-NR1 -} C(=O)-NR1-, -O-NR1-, or ^{-NR1 -} O-. Here, R ¹ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

In the aforementioned formula (I), G ¹ and G ² each independently represent a divalent aliphatic group having 1 to 20 carbon atoms which may have a substituent. In addition, each aliphatic group on the aforementioned aliphatic group may have at least one -O-, -S-, -O-C(=O)-, -C(=O)-O-, -O- interposed. C(=O)-O-, -NR ² -C(=O)-, -C(=O)-NR ² -, -NR ² - or -C(=O)-. Among them, the case where two or more -O- or -S- are adjacent to each other and intermediary is excluded. Here, R ² represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

In the aforementioned formula (I), Z ¹ and Z ² each independently represent an alkenyl group having 2 to 10 carbon atoms which may be substituted by a halogen atom.

In the aforementioned formula (I), A ^x represents an organic group having 2 to 30 carbon atoms having at least one aromatic ring selected from the group consisting of an aromatic hydrocarbon ring and an aromatic heterocyclic ring. "Aromatic ring" means a cyclic structure with generalized aromaticity following Hückel's rule, that is, a cyclic conjugated structure with (4n+2) π electrons, as well as thiophene, furan, benzothiazole The lone electron pair of heteroatoms such as sulfur, oxygen and nitrogen represented by etc. participates in the π electron system and exhibits an aromatic ring structure.

As said aromatic hydrocarbon ring, a benzene ring, a naphthalene ring, an anthracene ring, etc. are mentioned, for example. Examples of the aromatic heterocyclic ring include monocyclic aromatic rings such as pyrrole ring, furan ring, thiophene ring, pyridine ring, pyridine ring, pyrimidine ring, pyridine ring, pyrazole ring, imidazole ring, oxazole ring, and thiazole ring. Heterocycle; benzothiazole ring, benzoxazole ring, quinoline ring, oxazol ring, benzimidazole ring, benzopyrazole ring, benzofuran ring, benzothiophene ring, thiazolopyridine ring, oxazole Condensed aromatic heterocycles such as pyridine ring, thiazolopyridine ring, oxazolopyridine ring, thiazolopyridine ring, azolopyridine ring, thiazolopyrimidine ring and oxazolopyrimidine ring.

In the aforementioned formula (I), A ^y represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkenyl group having 2 to 20 carbon atoms which may have a substituent, or a carbon which may have a substituent Cycloalkyl groups of 3 to 12, alkynyl groups of 2 to 20 carbon atoms which may have substituents, -C(=O)-R ³ , -SO ₂ -R ⁴ , -C(=S)NH-R ⁹ or an organic group having 2 to 30 carbon atoms having at least one aromatic ring selected from the group consisting of an aromatic hydrocarbon ring and an aromatic heterocyclic ring. Here, R ³ represents an alkyl group with 1 to 20 carbon atoms which may have a substituent, an alkenyl group with 2 to 20 carbon atoms which may have a substituent, or a cycloalkane group with 3 to 12 carbon atoms which may have a substituent group or an aromatic hydrocarbon ring group with 5 to 12 carbon atoms. R ⁴ represents an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, a phenyl group or a 4-methylphenyl group. R ⁹ represents an alkyl group with 1 to 20 carbon atoms which may have a substituent, an alkenyl group with 2 to 20 carbon atoms which may have a substituent, a cycloalkyl group with 3 to 12 carbon atoms which may have a substituent, or An aryl group having 5 to 20 carbon atoms which may have a substituent. The aromatic ring which the said ^Ax and ^Ay have may have a substituent. In addition, the aforementioned A ^x and A ^y may form a ring together.

In the aforementioned formula (I), A ¹ represents a trivalent aryl group which may have a substituent.

In the aforementioned formula (I), A ² and A ³ each independently represent a divalent alicyclic hydrocarbon group having 3 to 30 carbon atoms which may have a substituent.

In the aforementioned formula (I), A ⁴ and A ⁵ each independently represent a divalent aryl group having 6 to 30 carbon atoms which may have a substituent.

In the aforementioned formula (I), Q ¹ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms which may have a substituent.

In the aforementioned formula (I), m and n each independently represent 0 or 1.

Wherein, in the aforementioned formula (I), one or both of Z ¹ -Y ⁷ - and -Y ⁸ -Z ² is acryloxy.

Specific examples of the compound (I) include compounds described in International Patent Publication No. 2016/171169, International Patent Publication No. 2017/057005, and International Patent Publication No. 2016/190435. In addition, the production of compound (I) can be carried out by the methods described in these documents.

Next, the reverse wavelength mesogen compound will be described.

The reverse wavelength mesogen compound is a compound that "does not exhibit liquid crystallinity in a single state, but exhibits liquid crystallinity in the mixture for evaluation after being mixed with the liquid crystal compound for evaluation in a specific mixing ratio". As the liquid crystal compound for evaluation, a forward wavelength dispersive liquid crystal compound which is "a liquid crystal compound that exhibits in-plane retardation of forward wavelength dispersion property in the case of uniform alignment" was used. By using the forward wavelength dispersive liquid crystal compound as the liquid crystal compound for evaluation, the evaluation of the wavelength dispersion property of the in-plane retardation of the reverse wavelength mesogen compound in the case of uniformly aligning the mixture for evaluation can be easily performed. Among them, as the liquid crystal compound for evaluation, a liquid crystal compound having a rod-like structure exhibiting a liquid crystal phase at 100° C. is preferable. Specific examples of particularly preferred liquid crystal compounds for evaluation include a cis-wavelength dispersive liquid crystal compound (Paliocolor (registered trademark) LC242 (manufactured by BASF Corporation)) having a structure disclosed in the following formula (E1), disclosed in the following The forward wavelength dispersive liquid crystal compound of the structure of formula (E2), etc. In the following formula, Me represents a methyl group.

"Hua 6"

"Hua 7"

In addition, the mixing ratio of the reverse wavelength mesogen compound to be mixed with the evaluation liquid crystal compound in order to obtain the evaluation mixture is usually 30 to 70 parts by weight relative to 100 parts by weight of the total of the evaluation liquid crystal compound and the reverse wavelength mesogen compound. at least any of the parts by weight. Therefore, as long as at least one mixing ratio of "in the range of 30 to 70 parts by weight relative to the total 100 parts by weight of the liquid crystal compound for evaluation and the reverse wavelength mesogen compound" is obtained, the reverse wavelength mesogen compound is mixed, and The mixture for evaluation that exhibits liquid crystallinity”, then “reverse wavelength is mixed at other mixing ratios in the range of 30 to 70 parts by weight relative to the total 100 parts by weight of the liquid crystal compound for evaluation and the reverse wavelength mesogen compound.” A mixture obtained from a mesogen compound" may not exhibit liquid crystallinity.

The fact that the mixture for evaluation developed liquid crystallinity can be confirmed by the following method.

The mixture for evaluation was apply|coated on a base material, and it was made to dry, and the sample film provided with the layered body of a base material and the mixture for evaluation was obtained. This sample film was placed on the thermal stage. The sample film was observed through a polarizing microscope while heating the sample film. When phase transition to the liquid crystal phase is observed in the layered body of the mixture for evaluation, it can be judged that the mixture for evaluation exhibits liquid crystallinity.

In addition, when the aforementioned mixture for evaluation is uniformly aligned, the reverse wavelength mesogen compound in the mixture for evaluation exhibits in-plane retardation of reverse wavelength dispersibility. Here, "uniformly aligning the mixture for evaluation" means forming a layer of the mixture for evaluation, and aligning the liquid crystal compound for evaluation in this layer body uniformly. Therefore, in the uniformly aligned mixture for evaluation, the long axis direction of the mesogen skeleton of the molecules of the liquid crystal compound for evaluation is generally aligned in a direction parallel to the plane of the aforementioned layer.

In addition, the so-called "in-plane retardation of the reverse wavelength mesogen compound in the mixture for evaluation that has been uniformly aligned exhibits reverse wavelength dispersion" refers to the in-plane retardation of the reverse wavelength mesogen compound contained in the mixture for evaluation at wavelengths of 450 nm and 550 nm. The in-plane retardations Re(450) and Re(550) satisfy Re(450)/Re(550)<1.00.

However, it is difficult to selectively measure only the in-plane retardation of the reverse wavelength mesogen compound in the layered body of the mixture for evaluation. Then, since the liquid crystal compound for evaluation is a forward wavelength dispersive liquid crystal compound, it can be confirmed that the reverse wavelength mesogen compound in the mixture for evaluation exhibits in-plane retardation of reverse wavelength dispersion by the following confirmation method.

A liquid crystal layer containing a liquid crystal compound for evaluation as a forward wavelength dispersion liquid crystal compound was formed, and the liquid crystal compound for evaluation was uniformly aligned in the liquid crystal layer. Then, the ratio Re(X450)/Re(X550) of the in-plane retardation Re(X450) and Re(X550) of the liquid crystal layer at wavelengths of 450 nm and 550 nm was measured.

Then, a layered body containing the mixture for evaluation of the liquid crystal compound for evaluation and the reverse wavelength mesogen compound was formed, and the mixture for evaluation was uniformly aligned in the layered body of the mixture for evaluation. Then, the in-plane retardation Re(Y450) and Re(Y550) ratios Re(Y450)/Re(Y550) of the layered body of the mixture for evaluation at wavelengths of 450 nm and 550 nm were measured.

As a result of the measurement, the "retardation ratio Re(X450)/Re(X550) of the liquid crystal layer without the reverse wavelength mesogen compound" is less than the "retardation ratio Re( When Y450)/Re(Y550)" is small, the reverse wavelength mesogen compound can be judged to be in-plane retardation exhibiting reverse wavelength dispersion.

In addition, from the viewpoint of making the desired effects of the present invention more favorable, in the aforementioned confirmation method, the in-plane retardation Re (Y550) of the layered body of the mixture for evaluation at wavelengths of 550 nm and 650 nm and the ratio of Re(Y650) Re(Y650)/Re(Y550)” is greater than “the ratio of the in-plane retardation Re(X550) to Re(X650) of the liquid crystal layer at wavelengths of 550 nm and 650 nm Re(X650)/Re (X550)” is better.

As the reverse wavelength mesogen compound, for example, a compound containing a main chain mesogen skeleton and a side chain mesogen skeleton bonded to the main chain mesogen skeleton in the molecule of the reverse wavelength mesogen compound can be used.

Furthermore, it is preferable that the reverse wavelength mesogen compound has polymerizability. Therefore, it is preferable that the reverse wavelength mesogen compound has a polymerizable group. When such a polymerizable reverse wavelength mesogen compound is used, the alignment state of the reverse wavelength mesogen compound can be easily fixed by polymerization. Therefore, an optically anisotropic layer having stable optical characteristics can be easily obtained.

The molecular weight of the reverse-wavelength mesogen compound, when it is a monomer, is preferably 300 or more, preferably 700 or more, more preferably 1000 or more, and preferably 2000 or less, preferably 1700 or less, 1500 or less is especially preferred. Since the reverse wavelength mesogen compound has the molecular weight as described above, the coatability of the coating liquid for forming the optically anisotropic layer can be optimized in particular.

The aforementioned reverse wavelength mesogen compounds may be used alone or in combination of two or more in any ratio.

As a reverse wavelength mesogen compound, the compound which does not exhibit liquid crystallinity among the compounds represented by the said formula (Ia) is mentioned, for example. As a preferable example of a reverse wavelength mesogen compound, the compound which does not exhibit liquid crystallinity among the compounds represented by the said formula (I) is mentioned. Among them, the following compounds are exemplified as particularly preferable reverse wavelength mesogen compounds.

"Hua 8"

Among the above-mentioned mesogen compounds, from the viewpoint of better exhibiting the desired effects of the present invention, "in the molecule of the mesogen compound, a ring selected from a benzothiazole ring (the following formula (10A) is contained) and a combination of a cyclohexyl ring (a ring of the following formula (10B)) and a benzene ring (a ring of the following formula (10C)); at least one of the group formed” is preferred.

"Hua 9"

By polymerizing the mesogen compound, a polymer of the mesogen compound is obtained. The specific method of polymerization is not particularly limited, and can be any method. Specifically, it can be performed by irradiating a coating liquid containing a mesogen compound with light. This method is described in detail later.

The optically anisotropic layer includes a mesogen compound combined with a positive type C polymer and a polymer of the mesogen compound. Specifically, the optically anisotropic layer may contain, in addition to the polymer of the mesogen compound, the unreacted mesogen compound that remains unpolymerized. The ratio of the mesogen compound is the ratio of the curing degree A in the specific range specified in this application.

The proportion of the mesogenic compound and its polymer in the total solid content of the optically anisotropic layer is preferably 20 wt % or more, preferably 30 wt % or more, more preferably 35 wt % or more, and 40 wt % or more % or more is particularly preferred, and preferably 60% by weight or less, more preferably 55% by weight or less, more preferably 50% by weight or less, and still more preferably 45% by weight or less. By making the ratio of the mesogen compound and its polymer more than the lower limit of the aforementioned range, the wavelength dispersion of the retardation Rth in the thickness direction of the optically anisotropic layer can be easily made close to the inverse dispersion property, and by being within the aforementioned range. Below the upper limit, in the optically anisotropic layer, the polymer of the mesogen compound can be uniformly dispersed, and the mechanical strength of the optically anisotropic layer can be improved.

[1.3. Arbitrary ingredients]

The optically anisotropic layer may further comprise a positive-type C polymer, a mesogen compound and a polymer of the mesogen compound in combination with any components.

The optically anisotropic layer has to contain a plasticizer. In the case where the optically anisotropic layer contains a cellulose derivative as the positive type C polymer, the optically anisotropic layer especially preferably contains a plasticizer in combination with a cellulose derivative. Examples of plasticizers include: xylitol pentacetate, xylitol pentapropionate, arabitol pentapropionate, triphenyl phosphate, including succinic acid Polyesters of residues with ethylene glycol residues, and polyesters comprising adipic acid residues with residues of ethylene glycol. The proportion of the plasticizer, in the total 100% by weight of the positive type C polymer and the plasticizer, is preferably 2.5% by weight or more, preferably 10% by weight or more, and preferably 25% by weight or less, with 20% by weight or less is preferable.

[1.4. Characteristics of Optically Anisotropic Layer: Refractive Index]

The optically anisotropic layer satisfies the formula (2). nz(A)>nx(A)≧ny(A) Formula (2) nx(A), ny(A) and nz(A) are the principal refractive indices of the optically anisotropic layers. The optically anisotropic layer having such refractive indices nx(A), ny(A), and nz(A) can be used as a positive-type C thin film. Therefore, when the optically anisotropic layer is incorporated into a circular polarizing plate and applied to an image display device, the reflection of external light can be suppressed in the inclined direction of the display surface of the image display device, so that the light for displaying the image can penetrate Polarized sunglasses. Furthermore, when the image display device is a liquid crystal display device, the viewing angle can usually be expanded. Therefore, when the display surface of the video display device is viewed from an oblique direction, the visibility of the video can be improved.

Among them, the refractive index nx(A) and the refractive index ny(A) of the optically anisotropic layer are preferably the same or close to each other. Specifically, the difference nx(A)−ny(A) between the refractive index nx(A) and the refractive index ny(A) is preferably 0.00000 to 0.00100, preferably 0.00000 to 0.00050, and particularly preferably 0.00000 to 0.00020 . Since the refractive index difference nx(A)-ny(A) falls within the aforementioned range, the optical design in the case of disposing the optically anisotropic layer in the image display device can be simplified, and it is not necessary to stick with other retardation films The adjustment of the fit direction.

[1.5. Characteristics of Optically Anisotropic Layer: Degree of Curing]

The optically anisotropic layer of the present invention satisfies the formula (3). 0.073<A _{C - H} /A _{C = O} (mesogen compound) < 0.125 Formula (3) In formula (3), A _{C - H} is the amount of the mesogen compound in the infrared absorption spectrum of the optically anisotropic layer. The infrared absorption related to the out-of-plane bending vibration of the C-H bond possessed by the acrylate structure, A _{C = O} (the mesogen compound) is in the infrared absorption spectrum of the optically anisotropic layer, "Acrylate of the mesogen compound" The sum of the infrared absorption related to the stretching vibration of the C=O bond possessed by the structure" and the "infrared absorption related to the stretching vibration of the C=O bond of the C=O bond derived from the acrylate structure of the mesogen compound" . In this application, the value _A represented by _A =AC _{- H} /AC _{= O} (mesenogen compound) may be referred to as the degree of curing A of the mesogen compound.

The curing degree A is a value determined according to the "amount of unreacted alkenoate structure contained in the optically anisotropic layer". When the polymerization reaction is not sufficiently advanced, the curing degree A is a large value. When the polymerization reaction has progressed to a high degree, the curing degree A has a smaller value. The degree of curing A is preferably greater than 0.073, more preferably greater than 0.076, and most preferably greater than 0.079. In addition, it is preferably less than 0.125, more preferably less than 0.122, and most preferably less than 0.119. A favorable color tone of the optically anisotropic layer can be realized by the degree of curing A in the optically anisotropic layer being equal to or more than the aforementioned lower limit value. On the other hand, by the degree of curing A in the optically anisotropic layer being equal to or less than the aforementioned upper limit value, high durability of the optically anisotropic layer can be achieved.

The infrared absorption spectrum of the optically anisotropic layer can be measured, for example, by total reflection measurement (ATR method).

As the measuring device, "Nicolet iS 5N" manufactured by Thermo Fisher SCIENTIFIC was used. The infrared absorption spectrum can be obtained as a graph showing the relationship between the wavenumber and the absorbance.

When the acrylate of the mesogen compound is polymerized, the vinyl group in the acrylate structure is converted into an ethyl extension, and the carbonyl group bonded to the vinyl group becomes a carbonyl group bonded to the ethyl extension. The "C=O bond derived from the C=O bond of the acrylate structure of the mesogen compound" means the C=O bond bonded to the carbonyl group of "the ethylidene group that appears as a result of the polymerization of the acrylate" Knot. For convenience of description, "the C-H bond of the acrylate structure of the mesogen compound" may be abbreviated as C-H _M hereinafter, and the "C=O bond of the acrylate structure of the mesogen compound""C=O M is abbreviated as C=O _M , and "C=O bond derived from C=O bond of acrylate structure of mesogen compound" is abbreviated as C=O _MD .

In the case where the peak related to the stretching vibration of C=O _M and the peak related to the stretching vibration of C=O _MD are not separated but have a single peak, the infrared absorption of this single peak can also be regarded as "the stretching vibration of C=O _M ". The sum of "Infrared absorption related to vibration" and "Infrared absorption related to stretching vibration of C=O _MD ".

As the value of A _{C - H} /A _{C = O} (mesogen compound), it is possible to use dividing "the area of the peaks related to the out-of-plane bending vibration of C - H _M (area _{C - H} )" by "C = O _M The value (area _{C - H} /area _{C = O} ) obtained by the sum of the area of the peaks related to the stretching vibration of C=O _MD (area _{C = O} )".

In the infrared absorption spectrum, the peaks associated with out-of-plane bending vibrations of C-H _M usually appear around 810 cm ^{− 1} . Moreover, the peaks related to the stretching vibration of C=O _M and the peaks related to the stretching vibration of C=O _MD usually appear around 1720 cm ^{− 1} .

When the components of the optically anisotropic layer have C=O bonds similar to this in addition to C=O _MD , there are cases where they cannot be distinguished in the infrared absorption spectrum. In this case, by forming a plurality of optically anisotropic layers with different ratios of components, and grasping the degree of influence of the ratio of each component on infrared absorption, quantification can be performed to exclude the influence of similar C=O bonding .

The case where the positive type C polymer has C=O bonds similar to C=O _MD is described as a specific example of this quantification.

In this example, if the infrared absorption spectrum of the optically anisotropic layer is measured, the infrared absorption A _{C = O} related to the stretching vibration of the C=O bond in this spectrum can be obtained as the sum of the following. AC _{= O} (polymer): Infrared absorption related to stretching vibration of _C =O bonds of positive type C polymers. A _{C = O} (mesogen compound): "Infrared absorption related to stretching vibration of unreacted _C =OM" and "stretching of C=O bond of polymer of mesogen compound (ie, C=O _MD )" Vibration-related infrared absorption" sum.

That is, the following formula (A1) holds. A _{C = O} = A _{C = O} (polymer) + A _{C = O} (mesogen compound) Formula (A1)

It is considered that the value of AC _{= O} (polymer) and the value of AC _{= O ( mesogen} compound) are proportional to the "weight ratio of these in the optically anisotropic layer". Therefore, the following formula (A2) holds true for the infrared absorption related to the ratio of each component in the optically anisotropic layer and the stretching vibration of the C=O bond. A _{C = O} = W (polymer) × a _{C = O} (polymer) + W (mesogen compound) × a _{C = O} (mesogen compound) (A2)

In the formula: W (polymer) is the weight ratio of the "positive type C polymer" to the "sum of the weight of the positive type C polymer and the weight of the mesogen compound and its polymer" in the optically anisotropic layer . W (the mesogen compound) is the weight ratio of "the mesogen compound and its polymer" to "the sum of the weight of the positive type C polymer and the weight of the mesogen compound and its polymer" in the optically anisotropic layer . That is, W (polymer)+W (mesogen compound)=1. a _{C = O} (polymer) is the coefficient and is the infrared absorption associated with the stretching vibration of the C=O bond per unit weight ratio of the positive C polymer. a _{C = O} (mesogen compound) is the coefficient, and is the “infrared absorption related to the stretching vibration of the C=O bond possessed by the acrylate structure per unit weight ratio of the mesogen compound and its polymer and is derived from acrylic acid” The sum of the infrared absorption related to the stretching vibration of the C=O bond of the ester structure".

The values of a _{C = O} (polymer) and a _{C = O} (mesogen compound) can be determined by "the ratio of the weight of the positive type C polymer to the weight of the mesogen compound and its polymer is much different. Each optically anisotropic layer was obtained by measuring the infrared absorption spectrum respectively. Specifically, A _{C = O} was measured for a plurality of optically anisotropic layers in which W (polymer) and W (mesogen compound) were different. Thereby, in many examples, the values of W (polymer), W (mesogen compound), and A _{C = O} are known. From these values and formula (A2), a _{C = O} (polymer) and a _{C = O} (liquid crystal which minimize the difference between the actual value and the theoretical value of A _{C = O} ) are calculated by the least squares method. original compound). From the calculated a _{C = O} (mesogen compound) and the known W (mesogen compound), A _{C = O} (mesogen compound) can be obtained.

The value of the curing degree A can be controlled by adjusting the irradiation intensity and time of the active energy ray to be irradiated during the production process of the optically anisotropic layer.

[1.6. Characteristics of Optically Anisotropic Layer: Others]

The optically anisotropic layer generally satisfies Equation (4) and Equation (5). 0.50＜Rth(A450)/Rth(A550)＜1.00 Formula (4) 1.00≦Rth(A650)/Rth(A550)＜1.25 Formula (5) Wherein, Rth(A450) is the above-mentioned optical anisotropic layer at a wavelength of 450 The retardation in the thickness direction of nm, Rth(A550) is the retardation in the thickness direction of the aforementioned optically anisotropic layer at a wavelength of 550 nm, and Rth(A650) is the retardation in the thickness direction of the aforementioned optically anisotropic layer at a wavelength of 650 nm.

If the aforementioned formula (4) is described in detail, Rth(A450)/Rth(A550) is usually greater than 0.50, preferably greater than 0.60, preferably greater than 0.65, and usually less than 1.00, preferably less than 0.90, It is better to be less than 0.85.

Furthermore, if the aforementioned formula (5) is described in detail, Rth(A650)/Rth(A550) is usually 1.00 or more, preferably 1.01 or more, more preferably 1.02 or more, and usually less than 1.25, and less than 1.25. 1.15 is better, and less than 1.10 is better.

In the optically anisotropic layer having the retardation Rth(A450), Rth(A550) and Rth(A650) in the thickness direction satisfying the above-mentioned formulas (4) and (5), the retardation Rth in the thickness direction exhibits reverse wavelength dispersion. Such an optically anisotropic layer whose retardation Rth in the thickness direction exhibits reverse wavelength dispersion can be used in a wider range in the inclination direction of the display surface of the image display device when it is applied to an image display device by incorporating a circular polarizing plate. The wavelength range plays the function of "suppressing the reflection of external light and allowing the light for displaying images to penetrate polarized sunglasses". Furthermore, when the image display device is a liquid crystal display device, the viewing angle can usually be effectively expanded. Therefore, the visibility of the image displayed on the display surface can be effectively improved.

The optically anisotropic layer preferably satisfies the formula (6). Re(A590)≦10 nm Formula (6) Wherein, Re(A590) is the in-plane retardation of the optically anisotropic layer at a wavelength of 590 nm.

If the aforementioned formula (6) is described in detail, Re(A590) is preferably 0 nm to 10 nm, preferably 0 nm to 5 nm, and particularly preferably 0 nm to 2 nm. When Re(A590) falls within the aforementioned range, the optical design of the case where the optically anisotropic layer is provided in the image display device can be simplified, and the adjustment of the bonding direction when bonding with other retardation films can be eliminated.

The optically anisotropic layer preferably satisfies the formula (7). -200 nm≦Rth(A590)≦-10 nm Formula (7) where Rth(A590) is the retardation of the optically anisotropic layer in the thickness direction at a wavelength of 590 nm.

If the aforementioned formula (7) is described in detail, the Rth (A590) is preferably -200 nm or more, preferably -130 nm or more, particularly preferably -100 nm or more, and preferably -10 nm or less, with -30 nm or less is preferable, and -50 nm or less is more preferable. The optically anisotropic layer with such Rth (A590) can suppress the reflection of external light in the inclined direction of the display surface of the image display device and reduce the The hue of the reflected light changes so that the light that displays the image can penetrate the polarized sunglasses. Furthermore, when the image display device is a liquid crystal display device, the viewing angle can usually be expanded. Therefore, when the display surface of the video display device is viewed from an oblique direction, the visibility of the video can be improved.

The total light transmittance of the optically anisotropic layer is preferably more than 80%, more preferably more than 85%, more preferably more than 90%. The total light transmittance can be measured with a UV-Vis spectrometer in the wavelength range of 400 nm to 700 nm.

The haze of the optically anisotropic layer is preferably 5% or less, more preferably 3% or less, particularly preferably 1% or less, and ideally 0%. The haze must comply with JIS K 7136:2000 and be measured by a haze meter (eg "Haze-gard II" manufactured by Toyo Seiki Co., Ltd.).

The optical anisotropy can be minimized by satisfying requirements such as the degree of curing and the change in haze due to heating. Specifically, the change ratio (haze value after heating/initial haze value) of the haze before and after heating at 85° C. and 500 hours should be the smaller. The haze change ratio is preferably set to be 5.0 or less, more preferably 4.0 or less, and more preferably 3.0 or less. The change in haze due to heating is usually a change in haze increase, but there are cases where haze decreases. The haze change ratio is limited to 0.3 or more, 0.4 or more, or 0.5 or more.

The optically anisotropic layer can be made colorless or a hue close to it by satisfying requirements such as the degree of curing. Specifically, the conventional positive-type C thin film having reverse wavelength dispersion Rth often has a yellow hue, while the optically anisotropic layer of the present invention should have a lower yellow hue. More specifically, for the optically anisotropic layer of the present invention, the b ^* value in the L ^* a ^* b ^* colorimetric system is preferably set to be 2.5 or less, preferably 2.2 or less, more preferably 2.0 or less . The lower limit of the b ^* value is ideally zero. b ^* It is worth observing by measuring the optically anisotropic layer with a spectrophotometer (eg, "V-550" manufactured by JASCO Corporation).

The thickness of the optically anisotropic layer is appropriately adjusted so that a desired retardation can be obtained. The specific thickness of the optically anisotropic layer is preferably 1.0 μm or more, more preferably 3.0 μm or more, and preferably 50 μm or less, preferably 40 μm or less, and particularly preferably 30 μm or less.

[1.7. Manufacturing method of optically anisotropic layer]

The optically anisotropic layer can be obtained by "comprising: step (a): a step of preparing a coating solution containing a positive type C polymer, a mesogen compound and a solvent; step (b): coating the coating solution on the support surface to obtain The process of coating the liquid layer; and the process (c): the process of irradiating the coating liquid layer with light to harden the coating liquid layer; the production method of ". Hereinafter, this manufacturing method is demonstrated as a manufacturing method of the optically anisotropic layer of this invention.

[1.7.1. Step (a): Preparation of coating solution]

The process of preparing a coating liquid can be performed by mixing a positive type C polymer, a mesogen compound, and a solvent. The "proportion of the positive type C polymer in the total solid content of the coating solution" and the "proportion of the mesogen compound in the total solid content of the coating solution" can be adjusted to be the same as the "positive type C polymer in the optically anisotropic layer" respectively. The same range as the "ratio of the mesogen compound in the optically anisotropic layer" and the "ratio of the mesogen compound in the optically anisotropic layer". When the production method of the present invention is carried out, a part of the mesogen compound in the coating liquid may remain in the optically anisotropic layer in an unpolymerized and unreacted state. However, in the case where the curing degree A is within the range specified in this application, the proportion of the unreacted mesogen compound is extremely small.

As the solvent, an organic solvent is usually used. Examples of the organic solvent include hydrocarbon solvents such as cyclopentane and cyclohexane; cyclopentanone, cyclohexanone, methyl ethyl ketone, acetone, methyl isobutyl ketone, and N-methylpyrrolidine. Ketone solvents such as ketones; acetate solvents such as butyl acetate and amyl acetate; halogenated hydrocarbon solvents such as chloroform, dichloromethane, and dichloroethane; 1,4-dioxa, cyclopentyl methyl ether, tetrahydrofuran, Ether solvents such as tetrahydropyran, 1,3-dioxan, 1,2-dimethoxyethane; aromatic hydrocarbon solvents such as toluene, xylene, 1,3,5-mesitylene; and the like of the mixture. The boiling point of the solvent is preferably 60°C to 250°C, and more preferably 60°C to 150°C, from the viewpoint of excellent handleability. In addition, a solvent may be used individually by 1 type, and may be used in combination of 2 or more types in arbitrary ratios.

The amount of the solvent is preferably adjusted to a desired range of the solid content concentration of the coating liquid as much as possible. The solid content concentration of the coating liquid is preferably 6% by weight or more, preferably 8% by weight or more, more preferably 10% by weight or more, and preferably 20% by weight or less, preferably 18% by weight or less, It is especially preferable that it is 15 weight% or less. When the solid content concentration of the coating liquid falls within the aforementioned range, an optically anisotropic layer having desired optical properties can be easily formed.

The coating liquid for forming the optically anisotropic layer may also contain any components in combination with the positive type C polymer, the mesogen compound and the solvent. Moreover, an arbitrary component may be used individually by 1 type, and may be used in combination of 2 or more types in arbitrary ratios.

The coating liquid must contain a polymerization initiator as an optional component. The type of the polymerization initiator can be appropriately selected depending on the type of the polymerizable group contained in the polymerizable compound in the coating liquid. The term "polymerizable compound" as used herein is a general term for compounds having polymerizability. Among them, photopolymerization initiators are preferred. As a photopolymerization initiator, a radical polymerization initiator, an anionic polymerization initiator, a cationic polymerization initiator, etc. are mentioned. Specific examples of commercially available photopolymerization initiators include: Irgacure 907, trade name: Irgacure 184, trade name: Irgacure 369, trade name: Irgacure 651, trade name: Irgacure 819, trade name: Irgacure 651, manufactured by BASF Corporation. Trade name: Irgacure 907, trade name: Irgacure 379, trade name: Irgacure 379EG, trade name: Irgacure OXE02 and trade name: Irgacure OXE04; trade name made by ADEKA: ADEKA OPTOMER N1919, etc. In addition, a polymerization initiator may be used individually by 1 type, and may be used in combination of 2 or more types in arbitrary ratios.

The amount of polymerization initiators such as photopolymerization initiators in the coating liquid is adjusted so that a desired degree of curing A can be obtained. In the coating liquid, the ratio of the polymerization initiator to 100 parts by weight of the mesogen compound is preferably 1 part by weight or more, preferably 2 parts by weight or more, preferably 10 parts by weight or less, and preferably 8 parts by weight or less is better.

The coating liquid must contain a crosslinking agent as an optional component. The type of the crosslinking agent is appropriately selected depending on the type of the polymerizable compound in the coating liquid. As an example of a crosslinking agent, a brand name: A-TMPT (trimethylolpropane triacrylate, the Shin-Nakamura Chemical Industry Co., Ltd. make) is mentioned. The crosslinking agent may be used alone or in combination of two or more in any ratio.

The amount of the crosslinking agent in the coating liquid is adjusted so as to obtain an optically anisotropic layer with desired physical properties. In the coating solution, the ratio of the crosslinking agent to 100 parts by weight of the mesogen compound is preferably 1 part by weight or more, preferably 2 parts by weight or more, preferably 10 parts by weight or less, and preferably 8 parts by weight or less. better.

The coating solution must contain "metals, metal complexes, dyes, pigments, fluorescent materials, phosphorescent materials, leveling agents, thixotropic agents, gelling agents, polysaccharides, surfactants, and ultraviolet absorbers." , infrared absorbers, antioxidants, ion exchange resins, metal oxides such as titanium oxide, etc. as optional components. The proportion of the optional additives is preferably 0.1 to 20 parts by weight with respect to 100 parts by weight of the positive type C polymer.

It is preferable that the coating liquid does not exhibit liquid crystallinity. By using a coating liquid that does not exhibit liquid crystallinity, the dispersion of the positive type C polymer and the mesogen compound in the optically anisotropic layer can be optimized. Moreover, by using the coating liquid which does not have liquid crystallinity, the generation|occurence|production of the misalignment of a mesogen compound by the influence of air disturbance, such as a drying wind, can be suppressed.

[1.7.2. Process (b): Coating]

In the step of applying the coating liquid on the support surface to obtain the coating liquid layer, as the support surface, any surface that can support the coating liquid layer may be used. As this support surface, from the viewpoint of optimizing the surface state of the optically anisotropic layer, a flat surface without concave portions and convex portions is generally used. As the aforementioned supporting surface, it is preferable to use the surface of the elongated substrate. In the case of using an elongated substrate, the coating liquid can be continuously applied to the continuously conveyed substrate. Therefore, by using the elongated base material, the optically anisotropic layer can be continuously produced, so that the productivity can be improved.

As the substrate, a substrate film is usually used. As the base film, "a film that can be used as a base material of an optical stack" should be appropriately selected. Among them, from the viewpoint of "a multilayer film including a base film and an optically anisotropic layer can be used as an optical film, and there is no need to peel off the optically anisotropic layer from the base film", a transparent film is used as the base film. better. Specifically, the total light transmittance of the base film is preferably above 80%, preferably above 85%, and particularly preferably above 88%.

The material of the base film is not particularly limited, and various resins can be used. Examples of resins include resins containing various polymers. Examples of the polymer include alicyclic structure-containing polymers, cellulose esters, polyvinyl alcohol, polyimide, UV penetrating acrylic, polycarbonate, polysiloxane, polyethersilver, and epoxy polymers. , polystyrene, and combinations of these. Among these, from the viewpoints of transparency, low hygroscopicity, dimensional stability and light weight, alicyclic structure-containing polymers and cellulose esters are preferred, and alicyclic structure-containing polymers are more preferred. good.

The alicyclic structure-containing polymer is a polymer having an alicyclic structure in the repeating unit, and is usually an amorphous polymer. As the alicyclic structure-containing polymer, any one of a polymer containing an alicyclic structure in the main chain and a polymer containing an alicyclic structure in a side chain can be used.

As an alicyclic structure, a cycloalkane structure, a cycloalkene structure etc. are mentioned, for example, From a viewpoint of thermal stability etc., a cycloalkane structure is preferable.

The number of carbon atoms constituting the repeating unit of an alicyclic structure is not particularly limited, but is preferably 4 or more, preferably 5 or more, more preferably 6 or more, and preferably 30 or less, with 20 The number is preferably less than or equal to 15, and the number is more preferably less than 15.

The proportion of repeating units having an alicyclic structure in the alicyclic structure-containing polymer may be appropriately selected depending on the purpose of use, but is preferably 50% by weight or more, more preferably 70% by weight or more, and preferably 90% by weight or more Excellent. By increasing the repeating unit having an alicyclic structure as described above, the heat resistance of the base film can be improved.

Examples of the alicyclic structure-containing polymers include (1) noralkene polymers, (2) monocyclic cycloolefin polymers, (3) cyclic conjugated diene polymers, and (4) vinyl alicyclic polymers Hydrocarbon polymers and hydrides of these, etc. Among these, from the viewpoint of transparency and moldability, normethylene polymers are preferred.

Examples of noralkene polymers include ring-opening polymers of noralkene monomers, ring-opening copolymers of noralkene monomers and other monomers capable of ring-opening copolymerization, and hydrogenation of these. Products; addition polymers of noralkene monomers, addition copolymers formed by noralkene monomers and other monomers that can be copolymerized, etc. Among these, from the viewpoint of transparency, a hydrogenated product of a ring-opening polymer of a normethylene monomer is particularly preferable.

The alicyclic structure-containing polymer may be selected from known polymers such as those disclosed in Japanese Patent Laid-Open No. 2002-321302.

When a resin containing an alicyclic structure-containing polymer is used as the material of the base film, the thickness of the base film is 1 μm from the viewpoint of facilitating “productivity improvement, thinning, and weight reduction”. ~1000 μm is preferred, 5 μm to 300 μm is preferred, and 30 μm to 100 μm is particularly preferred.

The resin containing the alicyclic structure-containing polymer may be composed of only the alicyclic structure-containing polymer, and may contain any admixture as long as the effect of the present invention is not significantly impaired. The ratio of the alicyclic structure-containing polymer in the resin containing the alicyclic structure-containing polymer is preferably 70% by weight or more, more preferably 80% by weight or more.

Suitable specific examples of the resin containing the "alicyclic structure-containing polymer" include "ZEONOR 1420" and "ZEONOR 1420R" manufactured by Zeon Corporation.

Examples of the coating method of the coating liquid include curtain coating, extrusion coating, roll coating, spin coating, dip coating, bar coating, spray coating, slant coating, printing coating, gravure coating Coating, die coating, gap coating and dipping. The thickness of the coating liquid to be applied can be appropriately set depending on the desired thickness of the required optically anisotropic layer.

[1.7.3. Drying]

After the step (b) and before the step (c), a step of drying the coating liquid layer may be performed as necessary. By drying, the solvent can be removed from the coating liquid layer, and the alignment of the solid content of the coating liquid can be stabilized. As a result, the step (c) can be performed in a state in which the solid content of the coating liquid is stable. As a specific method of drying, any method such as drying under heating, drying under reduced pressure, drying under heating under reduced pressure, and natural drying can be adopted.

The method for producing an optically anisotropic layer of the present invention can produce an optically anisotropic layer by a simple operation called "coating and curing a coating solution containing a combined positive type C polymer and a mesogen compound." Therefore, an alignment film as described in Patent Document 1 is not required. Therefore, the operation of so-called "adjustment of the compatibility between the reverse wavelength dispersion liquid crystal and the alignment film, and formation of the alignment film" is not required, so that the optically anisotropic layer can be easily produced.

Furthermore, the coating liquid containing the combined positive type C polymer and the mesogen compound can suppress the occurrence of uneven alignment of the mesogen compound due to the influence of air disturbance during drying. Therefore, an optically anisotropic layer having a uniform alignment state can be easily obtained in a wide range in the in-plane direction, and thus an optically anisotropic layer having an excellent in-plane state can be easily obtained. Therefore, it is possible to suppress white turbidity due to uneven alignment of the optically anisotropic layer.

[1.7.4. Process (c): Light irradiation]

By performing the step of irradiating light, a part of the acrylate structure of the mesogen compound is polymerized into a polymer of the mesogen compound. Through this polymerization, an optically anisotropic layer comprising a polymer of a positive type C polymer and a mesogen compound can be formed. For the irradiation of the coating liquid layer with light, a method suitable for "the properties of the components contained in the coating liquid such as the polymerizable compound and the polymerization initiator" can be appropriately selected. The irradiated light may include visible light, ultraviolet light, and infrared light. Among them, the method of irradiating with ultraviolet rays is preferable in terms of ease of operation.

The ultraviolet irradiation intensity is preferably in the range of 0.1 mW/cm ² to 1000 mW/cm ² , and preferably in the range of 0.5 mW/cm ² to 600 mW/cm ² . The ultraviolet irradiation time is preferably in the range of 1 second to 300 seconds, and preferably in the range of 3 seconds to 100 seconds. The ultraviolet integrated light amount (mJ/cm ² ) can be obtained from ultraviolet irradiation intensity (mW/cm ² )×irradiation time (seconds). The preferred integrated light intensity is 600 mJ/cm ² to 5000 mJ/cm ² . As the ultraviolet irradiation light source, a high pressure mercury lamp, a metal halide lamp, and a low pressure mercury lamp can be used. The step (c) is preferably carried out in an inert gas atmosphere such as a nitrogen atmosphere, since the ratio of the residual monomer tends to decrease.

The method for producing an optically anisotropic layer may include any steps other than the steps described above. For example, a process of peeling the optically anisotropic layer from the substrate may be included.

[2. Multilayer for transfer printing]

The multilayer for transfer of the present invention includes a base material and the above-mentioned optically anisotropic layer. Here, the multi-layer product for transfer refers to a member including a plurality of layers, and a part of the layers of the plurality of layers is transferred and used for the manufacture of a product including the part of the layers. In the multilayer for transfer of the present invention, the optically anisotropic layer is used for the manufacture of the aforementioned product.

As a base material, the same thing as the base material demonstrated in the manufacturing method of an optically anisotropic layer can be used. Among them, those that can be peeled off are preferable as the base material. The multilayered product for transfer provided with such a base material can be manufactured by carrying out "the manufacturing method of the said optically anisotropic layer using a base material".

Multilayers for transfer can be used in the manufacture of optical films. For example, after bonding the optically anisotropic layer and the resin film of the multilayer for transfer, the optical film including the optically anisotropic layer and the resin film can be produced by peeling off the base material.

[3. Optically anisotropic stack]

The optically anisotropic stack of the present invention includes the above-mentioned optically anisotropic layer and retardation layer.

[3.1. Optically anisotropic layer in optically anisotropic stack]

As the optically anisotropic layer of the optically anisotropic stack, the above-mentioned ones are used. However, the optically anisotropic layers in the optically anisotropic stack preferably satisfy the following formulas (12) and (13). Re(A590)≦10 nm Formula (12) −110 nm≦Rth(A590)≦−20 nm Formula (13) The definitions of Re(A590) and Rth(A590) are as described above.

If the aforementioned formula (12) is described in detail, Re(A590) is preferably 0 nm to 10 nm, preferably 0 nm to 5 nm, and particularly preferably 0 nm to 2 nm. With Re(A590) falling within the aforementioned range, the optical design in the case of disposing the optically anisotropic stack in the image display device can be simplified.

Further, if the above-mentioned formula (13) is described in detail, Rth (A590) is preferably -110 nm or more, preferably -100 nm or more, more preferably -20 nm or less, and preferably -40 nm or less. , preferably below -50 nm. When an optically anisotropic stack having an optically anisotropic layer having such Rth (A590) is incorporated into a circularly polarizing plate and applied to an image display device, the optically anisotropic stack can be used in the oblique direction of the display surface of the image display device. Effectively play the function of "suppressing the reflection of external light, allowing the light of the displayed image to penetrate the polarized sunglasses". Therefore, when the display surface of the image display device is viewed from an oblique direction, the visibility of the image can be effectively improved.

[3.2. Retardation layer in optically anisotropic stack]

[3.2.1. Optical properties of retardation layer]

The retardation layer is a layer that satisfies the formula (8). nx(B)>ny(B)≧nz(B) Formula (8) where nx(B), ny(B) and nz(B) are the principal refractive indices of the retardation layer. The optically anisotropic stack having such a retardation layer can be combined with a linear polarizer to manufacture a circular polarizer. The circular polarizing plate, arranged on the display surface of the image display device, can suppress the reflection of external light when the display surface is viewed from the front direction, so that the light of the displayed image can penetrate the polarized sunglasses, so the image quality can be improved. visibility.

Among them, the refractive index ny(B) and the refractive index nz(B) of the retardation layer are preferably the same or close to each other. Specifically, the absolute value of the difference between the refractive index ny(B) and the refractive index nz(B) |ny(B)−nz(B)| is preferably 0.00000 to 0.00100, more preferably 0.00000 to 0.00050, and 0.00000 to 0.00020 is particularly preferred. Since the absolute value of the refractive index difference |ny(B)−nz(B)| falls within the aforementioned range, the optical design in the case of disposing the optically anisotropic stack in the image display device can be simplified.

The retardation layer preferably satisfies the formula (11). 110 nm≦Re(B590)≦170 nm Formula (11) Among them, Re(B590) is the retardation of retardation layer in the plane at a wavelength of 590 nm.

If the aforementioned formula (11) is described in detail, Re(B590) is preferably 110 nm or more, preferably 120 nm or more, particularly preferably 130 nm or more, more preferably 170 nm or less, and 160 nm or less. Preferably, it is preferably below 150 nm. An optically anisotropic stack having such a retardation layer of Re(B590) can be combined with a linear polarizer to obtain a circular polarizer. By arranging the circular polarizing plate on the display surface of the image display device, when the display surface is viewed from the front direction, the reflection of external light can be suppressed, so that the light of the displayed image can penetrate the polarized sunglasses, so the image quality can be improved. visibility.

The retardation layer preferably satisfies the equations (9) and (10). 0.75＜Re(B450)/Re(B550)＜1.00 Equation (9) 1.01＜Re(B650)/Re(B550)＜1.25 Equation (10) Among them, Re(B450) is the difference between the aforementioned retardation layer at a wavelength of 450 nm. In-plane retardation, Re(B550) is the in-plane retardation of the retardation layer at a wavelength of 550 nm, and Re(B650) is the in-plane retardation of the retardation layer at a wavelength of 650 nm.

If the aforementioned formula (9) is described in detail, Re(B450)/Re(B550) is preferably greater than 0.75, preferably greater than 0.78, particularly preferably greater than 0.80, and preferably less than 1.00, and less than 0.95 is better, and less than 0.90 is even better.

If the aforementioned formula (10) is described in detail, Re(B650)/Re(B550) is preferably greater than 1.01, preferably greater than 1.02, particularly preferably greater than 1.04, and preferably less than 1.25, and less than 1.22 is better, and less than 1.19 is even better.

The retardation layer having the in-plane retardation Re(B450), Re(B550) and Re(B650) satisfying the above-mentioned equations (9) and (10), the in-plane retardation Re exhibits reverse wavelength dispersion. The optically anisotropic stack including the retardation layer having such an in-plane retardation Re exhibiting reverse wavelength dispersion can be applied in the front direction of the display surface of the image display device in the case of incorporating a circular polarizing plate and applying it to an image display device. On the other hand, it has the function of "suppressing the reflection of external light and allowing the light for displaying images to penetrate the polarized sunglasses" in a wider wavelength range. Therefore, the visibility of the image displayed on the display surface can be effectively improved.

The in-plane slow axis direction of the retardation layer is arbitrary, and can be arbitrarily set depending on the application of the optically anisotropic stack. Among them, when the optically anisotropic stack is a long film, the angle between the slow axis of the retardation layer and the width direction of the film is preferably more than 0° and less than 90°. And in a certain state, the angle between the slow axis in the plane of the retardation layer and the width direction of the film can be determined as the so-called 15°±5°, 22.5°±5°, 45°±5° or 75°. °±5° is better, 15°±4°, 22.5°±4°, 45°±4° or 75°±4° is better, 15°±3°, 22.5°±3°, 45° A specific range of ±3° or 75°±3° is more preferable. By having such an angular relationship, it becomes possible to "bond the optically anisotropic stack to an elongated linear polarizer by roll-to-roll to efficiently manufacture a circular polarizer".

The total light transmittance of the retardation layer is preferably more than 80%, more preferably more than 85%, and more preferably more than 90%. Further, the haze of the retardation layer is preferably 5% or less, more preferably 3% or less, particularly preferably 1% or less, and ideally 0%.

[3.2.2. Stretched film layer as retardation layer]

As the retardation layer as described above, a stretched film layer can be used. When a stretched film layer is used as a retardation layer, the stretched film layer may contain a resin which is a material of the base film described in the method for producing an optically anisotropic layer. A film layer containing such a resin can exhibit optical properties such as retardation by performing a stretching treatment. Among them, the stretched film layer preferably contains a polymer containing an alicyclic structure.

The stretching direction of the stretched film layer is arbitrary. Therefore, the extending direction may be the longitudinal direction, the width direction, or the oblique direction. Furthermore, among these extension directions, extension may be performed in two or more directions. Here, the oblique direction refers to the in-plane direction of the film and is not parallel to either the longitudinal direction or the width direction.

Among them, the stretched thin film layer is preferably an oblique stretched thin film layer. That is, the stretched film layer is preferably "a long film that extends in a direction that is not parallel to both the longitudinal direction and the width direction of the film". In the case of an obliquely extending film layer, the angle between the width direction of the film and the extending direction is specifically set to exceed 0° and less than 90°. By using such an obliquely stretched film layer as a retardation layer, it becomes possible to "laminate an optically anisotropic stack to a long linear polarizer by roll-to-roll to efficiently manufacture a circular polarizer".

The angle between the extension direction and the width direction of the film can be determined as the so-called 15°±5°, 22.5°±5°, 45°±5° or 75°±5°, preferably 15°±4°, 22.5°±4°, 45°±4° or 75°±4° are preferred, 15°±3°, 22.5°±3°, 45°±3° or 75°±3° are more preferred scope. By having such an angular relationship, the optically anisotropic stack can be made into a material capable of efficiently producing a circularly polarizing plate.

Furthermore, the aforementioned stretched film layer preferably has a multi-layer structure including a plurality of layers. The stretched film layer having a multi-layer structure can exert various properties by combining the functions of the layers included in the stretched film layer. For example, the stretched film layer is provided with "in this order: a first outer layer made of a resin containing a polymer, an intermediate layer made of a resin containing a polymer and an ultraviolet absorber, and a resin containing a polymer The resulting second outer layer" is preferred. At this time, the polymers contained in each layer may be different, but are preferably the same. The stretched film layer having the first outer layer, the intermediate layer and the second outer layer can inhibit the penetration of ultraviolet rays. In addition, since the first outer layer and the second outer layer are provided on both sides of the intermediate layer, exudation of the ultraviolet absorber can be suppressed.

The amount of the ultraviolet absorber in the resin contained in the intermediate layer is preferably 3 wt % or more, preferably 4 wt % or more, more preferably 5 wt % or more, and preferably 20 wt % or less. 18 weight% or less is preferable, and 16 weight% or less is especially preferable. When the amount of the ultraviolet absorber is equal to or higher than the lower limit of the aforementioned range, the ability of the stretched film layer to prevent penetration of ultraviolet rays can be improved, and by being equal to or less than the upper limit of the aforementioned range, the resistance of the stretched film layer to the lower limit value of the aforementioned range can be improved. Transparency of visible light.

The thickness of the intermediate layer is preferably "set so that the ratio represented by "thickness of the intermediate layer"/"thickness of the entire stretched film layer" falls within a specific range". The aforementioned specific range is preferably more than 1/5, more preferably more than 1/4, more preferably more than 1/3, and preferably less than 80/82, more preferably less than 79/82, more preferably 78/ Below 82 is preferred. When the ratio is equal to or higher than the lower limit of the aforementioned range, the ability of the stretched film layer to prevent penetration of ultraviolet rays can be particularly enhanced, and by being equal to or less than the upper limit of the aforementioned range, the thickness of the stretched film layer can be thinned.

The thickness of the stretched film layer as the retardation layer is preferably 10 μm or more, more preferably 13 μm or more, particularly preferably 15 μm or more, and preferably 60 μm or less, preferably 58 μm or less, It is especially preferable to be 55 μm or less. Desired retardation can be exhibited by extending the thickness of the thin film layer to be equal to or more than the lower limit value of the aforementioned range, and thinning can be achieved by being equal to or less than the upper limit value of the aforementioned range.

The stretched thin film layer can be produced, for example, by a method including a step of preparing the pre-stretched thin film layer and a process of extending the prepared pre-stretched thin film layer.

The pre-stretching film layer can be produced, for example, by "molding a resin made of the material of the stretched film layer by an appropriate molding method". As a shaping|molding method, a casting shaping|molding method, an extrusion shaping|molding method, an inflatable shaping|molding method, etc. are mentioned, for example. Among them, the melt extrusion method that does not use a solvent can effectively reduce the amount of residual volatile components, and is preferable from the viewpoint of the global environment and the working environment and the viewpoint of excellent production efficiency. As the melt extrusion method, an inflatable method using a die, etc. are mentioned, and among them, a method using a T die is preferable from the viewpoint of being excellent in productivity and thickness accuracy.

In the case of producing a stretched film layer having a multi-layer structure, one having a multi-layer structure is usually prepared as a pre-stretch film layer. The pre-stretching film layer having such a multilayer structure can be produced by molding a resin corresponding to each layer included in the multilayer structure, for example, by a molding method such as a co-extrusion method and a co-casting method. Among these molding methods, the co-extrusion method is preferable because it is excellent in production efficiency, and it is difficult for volatile components to remain in the film. Examples of the co-extrusion method include a co-extrusion T-die method, a co-extrusion aeration method, and a co-extrusion lamination method. Among them, the co-extrusion T-die method is preferred. For the co-extrusion T-die method, there are feed block method and multi-manifold method, which can reduce the thickness unevenness, especially the multi-manifold method.

By molding the resin as described above, a long pre-stretching film can be obtained. By stretching this pre-stretched film, a stretched film layer can be obtained. The stretching is usually carried out continuously while the pre-stretching film is conveyed in the longitudinal direction. In this case, the extending direction may be the longitudinal direction of the film or the width direction, but the oblique direction is preferable. In addition, the extension may be free uniaxial extension that does not apply a restraining force other than the extension direction, or may be an extension that applies a restraining force other than the extension direction. Such stretching can be performed using any stretching machine such as a roll stretching machine and a tenter stretching machine.

The stretching ratio is preferably 1.1 times or more, more preferably 1.15 times or more, particularly preferably 1.2 times or more, more preferably 3.0 times or less, more preferably 2.8 times or less, and particularly preferably 2.6 times or less. The refractive index in the stretching direction can be enlarged by making the stretching magnification more than the lower limit value of the aforementioned range. In addition, by setting it below the upper limit value, the slow axis direction of the stretched thin film layer can be easily controlled.

The stretching temperature is preferably above Tg-5℃, preferably above Tg-2℃, especially preferably above Tg℃, and preferably below Tg+40℃, preferably below Tg+35℃, preferably below Tg+30℃ Excellent. The "Tg" here means the highest temperature among the glass transition temperatures of the polymer contained in the thin film layer before stretching. By setting the stretching temperature within the aforementioned range, the molecules contained in the thin film layer before stretching can be surely aligned, so that a stretched thin film layer that can function as a retardation layer having desired optical properties can be easily obtained.

[3.2.3. Liquid crystal layer as retardation layer]

As the retardation layer as described above, a liquid crystal layer containing a liquid crystal compound (hereinafter referred to as "liquid crystal compound for retardation layer" as appropriate) whose alignment state can be fixed can be used. In this case, as the liquid crystal compound for the retardation layer, it is preferable to use the aforementioned reverse wavelength dispersion liquid crystal compound which has been uniformly aligned. Thereby, even in the retardation layer, the same advantages as those described in the item of the optically anisotropic layer can be obtained. Among them, as the liquid crystal layer of the retardation layer, "containing a liquid crystal compound represented by the following formula (II) whose alignment state can be fixed" is particularly preferable.

"Hua 10"

In the aforementioned formula (II), Y ¹ to Y ⁸ , G ¹ , G ² , Z ¹ , Z ² , A ^x , A ^y , A ¹ to A ⁵ , Q ¹ , m and n represent the same as those in formula (I ) ) has the same meaning as in . Therefore, the liquid crystal compound represented by the formula (II) represents the same compound as the liquid crystal compound represented by the formula (I). Wherein, in formula (I), one or both of Z ¹ -Y ⁷ - and -Y ⁸ -Z ² is acryloxy, on the other hand, in formula (II), these two Alternatively, groups other than acryloxy may be used.

The thickness of the liquid crystal layer as the retardation layer is not particularly limited, and is appropriately adjusted so that characteristics such as retardation can be brought into a desired range. The specific thickness of the liquid crystal layer is preferably 0.5 μm or more, preferably 1.0 μm or more, preferably 10 μm or less, preferably 7 μm or less, and particularly preferably 5 μm or less.

The liquid crystal layer serving as the retardation layer can be produced, for example, by a method including: a step of preparing a liquid crystal composition containing a liquid crystal compound for a retardation layer; applying the liquid crystal composition to a support to obtain a liquid crystal composition A step of aligning the retardation layer included in the layered body of the liquid crystal composition with a liquid crystal compound.

In the process of preparing a liquid crystal composition, the liquid crystal compound for retardation layers and optional components used as needed are usually mixed to obtain a liquid crystal composition.

The liquid crystal composition must contain a polymerizable monomer as an optional component. The "polymerizable monomer" especially refers to compounds other than the above-mentioned liquid crystal compound for retardation layers, among compounds having polymerization ability and functioning as monomers. As the polymerizable monomer, for example, one having one or more polymerizable groups per molecule can be used. In the case of a crosslinkable monomer having two or more polymerizable groups per molecule of the polymerizable monomer, crosslinkable polymerization can be achieved. Examples of the polymerizable group include the same groups as "groups Z ¹ -Y ⁷ - and Z ² -Y ⁸ - or a part thereof in the compound (I)", and more specifically, propylene Acryloyl, methacryloyl and epoxy groups. Moreover, a polymerizable monomer may be used individually by 1 type, and may be used in combination of 2 or more types in arbitrary ratios.

In the liquid crystal composition, the ratio of the polymerizable monomer is preferably 1 to 100 parts by weight, preferably 5 to 50 parts by weight, relative to 100 parts by weight of the liquid crystal compound for retardation layer.

The liquid crystal composition must contain a photopolymerization initiator as an optional component. As a polymerization initiator, the same thing as the polymerization initiator contained in the coating liquid for manufacture of an optically anisotropic layer is mentioned, for example. In addition, a polymerization initiator may be used individually by 1 type, and may be used in combination of 2 or more types in arbitrary ratios.

In the liquid crystal composition, the ratio of the polymerization initiator is preferably 0.1 to 30 parts by weight, preferably 0.5 to 10 parts by weight, relative to 100 parts by weight of the polymerizable compound.

The liquid crystal composition must contain a surfactant as an optional component. As the surfactant, a nonionic surfactant is preferable. As a nonionic surfactant, a commercial item can be used. For example, a nonionic surfactant which is an oligomer with a molecular weight of about several thousand can be used. As specific examples of these surfactants, "PF-151N", "PF-636", "PF-6320", "PF-656", "PF-6520", "PF-6520", "PF-636", "PF-6320", "PF-656", "PF-6520", "PF-636" from OMNOVA Co., Ltd. -3320", "PF-651", "PF-652"; "FTX-209F", "FTX-208G", "FTX-204D", "601AD" from NEOS FTERGENT; "KH- 40", "S-420", etc. In addition, one type of surfactant may be used alone, or two or more types may be used in combination in any ratio.

In the liquid crystal composition, the ratio of the surfactant is preferably 0.01 to 10 parts by weight, preferably 0.1 to 2 parts by weight, relative to 100 parts by weight of the polymerizable compound.

The liquid crystal composition must contain a solvent as an optional component. As a solvent, the same thing as the solvent contained in the coating liquid for manufacture of an optically anisotropic layer is mentioned, for example. In addition, a solvent may be used individually by 1 type, and may be used in combination of 2 or more types in arbitrary ratios.

In the liquid crystal composition, the ratio of the solvent is preferably 100 parts by weight to 1000 parts by weight with respect to 100 parts by weight of the polymerizable compound.

Furthermore, the liquid crystal composition must contain "metals, metal complexes, dyes, pigments, fluorescent materials, phosphorescent materials, leveling agents, thixotropic agents, gelling agents, polysaccharides, ultraviolet absorbers, infrared absorbers. , antioxidants, ion exchange resins, metal oxides such as titanium oxide, etc. as optional components. The ratio of these additives is preferably 0.1 to 20 parts by weight, respectively, with respect to 100 parts by weight of the polymerizable compound.

After preparing the liquid crystal composition as described above, a step of coating the liquid crystal composition on a support to obtain a layer of the liquid crystal composition is performed. As the support, it is preferable to use an elongated support. In the case of using an elongated support, the liquid crystal composition can be continuously coated on the continuously conveyed support. Therefore, by using the elongated support, the liquid crystal layer serving as the retardation layer can be continuously produced, so that the productivity can be improved.

In the case of applying the liquid crystal composition to the support, it is preferable to apply a moderate tension (usually 100 N/m to 500 N/m) to the support to reduce the conveyance vibration of the support and maintain the flatness. state of coating. The so-called flatness is the amount of vibration perpendicular to the width direction of the support body and the vertical direction of the conveying direction, and is ideally 0 mm, usually 1 mm or less.

As a support, a support film is usually used. As the support film, "a film that can be used as a support of an optical stack" should be appropriately selected. Among them, from the viewpoint of "the optically anisotropic stack including the support film, the retardation layer, and the optically anisotropic layer can be used as an optical film, and the peeling of the support film is not required", as the support film, the A transparent film is preferred. Specifically, the total light transmittance of the support film is preferably 80% or higher, preferably 85% or higher, and particularly preferably 88% or higher.

The material of the support film is not particularly limited, and various resins can be used. As an example of a resin, the resin containing "the polymer demonstrated as the material which can be used for the base material used for formation of an optically anisotropic layer" is mentioned. Among these, from the viewpoint of transparency, low hygroscopicity, dimensional stability and light weight, as the polymer containing resin, alicyclic structure-containing polymers and cellulose esters are preferable, and those containing Alicyclic structure polymers are preferred.

As the support, one having an anchoring force must be used. The so-called alignment restraining force of the support refers to the property of the support "that aligns the liquid crystal compound for the retardation layer in the liquid crystal composition coated on the support".

The alignment restricting force can be imparted by "processing a member such as a film made of the material of the support to impart an alignment restricting force". As an example of this treatment, stretching treatment and rubbing treatment can be mentioned.

In a preferred aspect, the support system extends the film. By forming this stretched film, it is possible to form a support body having an alignment restraining force corresponding to the extending direction.

The stretching direction of the stretched film is arbitrary. Therefore, the extending direction may be the longitudinal direction, the width direction, or the oblique direction. Furthermore, among these extension directions, extension may be performed in two or more directions. The elongation ratio should be appropriately set within the "range in which the alignment restraining force is generated on the surface of the support". In the case where the material of the support is a resin having a positive intrinsic birefringence value, the molecules are aligned in the extension direction and exhibit a slow axis in the extension direction. For stretching, a known stretching machine such as a tenter stretching machine is used.

In a more preferred form, the support system extends the film diagonally. When the support system stretches the film obliquely, the angle between the stretching direction and the width direction of the stretched film should be more than 0° and less than 90°. By using such an obliquely stretched film as a support, the optically anisotropic stack can be made into a material capable of efficiently producing a circularly polarizing plate.

In addition, in a certain aspect, the angle between the stretching direction and the width direction of the stretched film may be so-called 15°±5°, 22.5°±5°, 45°±5° or 75°±5° Preferably, 15°±4°, 22.5°±4°, 45°±4° or 75°±4° are preferred, 15°±3°, 22.5°±3°, 45°±3° or 75°±3° is a more preferable specific range. By having such an angular relationship, the optically anisotropic stack can be made into a material capable of efficiently producing a circularly polarizing plate.

Examples of the coating method of the liquid crystal composition include curtain coating, extrusion coating, roll coating, spin coating, dip coating, bar coating, spray coating, slant coating, printing coating, Gravure coating, die coating, gap coating and dipping. The thickness of the layer body of the liquid crystal composition to be applied can be appropriately set depending on the desired thickness of the liquid crystal layer as the retardation layer required.

After applying the liquid crystal composition on the support to obtain a layer of the liquid crystal composition, a step of aligning the retardation layer contained in the layer of the liquid crystal composition with the liquid crystal compound is performed. Thereby, the liquid crystal compound for retardation layer contained in the layered body of the liquid crystal composition is aligned in the alignment direction corresponding to the alignment restriction force of the support. For example, when a stretched film is used as a support, the liquid crystal compound for the retardation layer included in the layered body of the liquid crystal composition is aligned parallel to the extending direction of the stretched film.

The alignment of the liquid crystal compound for the retardation layer may be directly achieved by coating, but may be achieved by performing alignment treatment such as heating after coating as required. The conditions of the alignment treatment can be appropriately set depending on the properties of the liquid crystal composition to be used. For example, the conditions of treatment at a temperature of 50°C to 160°C for 30 seconds to 5 minutes are determined.

By aligning the liquid crystal compound for the retardation layer in the layered body of the liquid crystal composition as described above, the desired optical properties are exhibited in the layered body of the liquid crystal composition, so that a liquid crystal layer that can function as a retardation layer can be obtained. .

As a manufacturing method of the liquid crystal layer of the said retardation layer, an arbitrary process may be further included. In the manufacturing method of a liquid crystal layer, the process of drying the layer body of a liquid crystal composition, or a liquid crystal layer, for example, can also be performed. This drying can be achieved by drying methods such as natural drying, heating drying, drying under reduced pressure, and heating drying under reduced pressure.

Moreover, as a manufacturing method of the liquid crystal layer of a retardation layer, after aligning the liquid crystal compound for retardation layers contained in a liquid crystal composition, the process of fixing the alignment state of the liquid crystal compound for retardation layers may be performed, for example. In this step, the alignment state of the liquid crystal compound for the retardation layer is usually fixed by polymerizing the liquid crystal compound for the retardation layer. In addition, by polymerizing the liquid crystal compound for the retardation layer, the rigidity of the liquid crystal layer can be improved, and the mechanical strength can be improved.

For the polymerization of the liquid crystal compound for the retardation layer, a method suitable for the properties of the components of the liquid crystal composition can be appropriately selected. For example, the method of irradiating light is preferable. Among them, the method of irradiating with ultraviolet rays is preferable in terms of ease of operation. The irradiation conditions such as the ultraviolet irradiation intensity, the ultraviolet irradiation time, the ultraviolet integrated light amount, and the ultraviolet irradiation light source can be adjusted within the same range as the irradiation conditions in the method for producing the optically anisotropic layer.

During the polymerization, the liquid crystal compound for the retardation layer is usually polymerized in a state in which the alignment of its molecules is maintained. Therefore, by the aforementioned polymerization, a liquid crystal layer containing a polymer of an aligned liquid crystal compound for retardation layer can be obtained, and the aligned liquid crystal compound for retardation layer is in phase with that contained in the liquid crystal composition before polymerization. The difference layer is aligned in a direction parallel to the alignment direction of the liquid crystal compound. Therefore, for example, when a stretched film is used as a support, a liquid crystal layer having an alignment direction parallel to the extending direction of the stretched film can be obtained. The term "parallel" here means that the deviation between the extending direction of the stretched film and the alignment direction of the polymer of the liquid crystal compound for retardation layer is usually ±3°, preferably ±1°, and ideally 0°.

In the liquid crystal layer as the retardation layer produced by the above-mentioned production method, the molecules of the polymer obtained from the liquid crystal compound for the retardation layer preferably have alignment regularity with respect to the horizontal alignment of the support film. For example, in the case of using a film having an alignment restriction force as a support film, the molecular level of the polymer of the liquid crystal compound used for the retardation layer in the liquid crystal layer can be aligned. Here, the term "horizontal alignment" of the molecules of the polymer of the liquid crystal compound for retardation layer with respect to the support film refers to "the mesogen skeleton derived from the structural unit of the liquid crystal compound for retardation layer contained in the polymer. The average direction of the long axis direction is parallel or nearly parallel to the film surface” (for example, the angle between the film surface and the film surface is within 5°). As in the case of using the compound represented by the formula (II) as the liquid crystal compound for the retardation layer, in the case of the liquid crystal layer having a plurality of types of mesogen skeletons whose alignment directions are different, the longest type of mesogen skeleton among these The direction in which the long axis direction is aligned is usually referred to as the alignment direction.

In addition, the process of peeling a support body after obtaining a liquid crystal layer as a manufacturing method of the liquid crystal layer of a retardation layer may be included.

[3.3. Any layer in an optically anisotropic stack]

The optically anisotropic stack may further comprise any combination of layers in the optically anisotropic layer and the retardation layer. As an arbitrary layer body, a bonding layer, a hard-coat layer, etc. are mentioned, for example.

[3.4. Manufacturing method of optically anisotropic stack]

The optically anisotropic stack can be produced, for example, by the following production method 1 or 2.

. Manufacturing method 1:

It includes the process of "manufacturing a retardation layer" and "using the aforementioned retardation layer as a base material, and by carrying out the above-mentioned manufacturing method of an optically anisotropic layer, the optically anisotropic layer is formed on the retardation layer, and obtained. The manufacturing method of the process of the optically anisotropic stack.

In the case where the coating liquid is applied on the retardation layer in the production method 1, an optically anisotropic layer can be formed on the retardation layer by drying the coating liquid layer to obtain an optically anisotropic stack.

. Manufacturing method 2:

It includes a process of "manufacturing a retardation layer", a process of "manufacturing a multilayer for transfer", and "laminating an optically anisotropic layer and a retardation layer of the multilayer for transfer to obtain an optically anisotropic stack" ” process and the process of “peeling the substrate of the multi-layer material for transfer”.

As in the production method 2, when the optically anisotropic layer and the retardation layer are bonded together to produce an optically anisotropic stacked body, an appropriate adhesive can be used for bonding. As this adhesive, for example, the same adhesive used for the polarizing plate described later can be used.

Moreover, the manufacturing method of the said optically anisotropic laminated body may contain arbitrary processes other than the said process. For example, the aforementioned manufacturing method may include a step of providing an arbitrary layer body such as a hard coat layer.

[4. Polarizing plate]

The polarizing plate of the present invention includes a "linear polarizer" and "the above-mentioned optically anisotropic layer, multi-layer for transfer, or optically anisotropic stack". Such a polarizing plate can improve the visibility of an image when the image display device is viewed from an oblique direction by being installed in the image display device.

As the linear polarizer, a known linear polarizer "in use in devices such as liquid crystal display devices and other optical devices" can be used. Examples of linear polarizers include: a film obtained by "adsorbing iodine or a dichroic dye on a polyvinyl alcohol film and then uniaxially extending it in a boric acid bath"; It is a film obtained by extending a polyvinyl alcohol film and further modifying a part of the polyvinyl alcohol unit in the molecular chain into a polyvinyl alcohol unit. In addition, other examples of linear polarizers include grid polarizers, multilayer polarizers, and cholesteric liquid crystal polarizers that have a function of separating polarized light into reflected light and transmitted light. Among these, as the linear polarizer, a polarizer containing polyvinyl alcohol is preferable.

If natural light is incident on the linear polarizer, only one beam of polarized light will penetrate. The degree of polarization of the linear polarizer is not particularly limited, but preferably more than 98%, more preferably more than 99%.

In addition, the thickness of the linear polarizer is preferably 5 μm to 80 μm.

Furthermore, the polarizing plate may be provided with a bonding layer for bonding the "linear polarizer" and the "optically anisotropic layer, the multilayer for transfer, or the optically anisotropic stack". As the bonding layer, a layer obtained by curing a curable bonding agent can be used. As the curable adhesive, a thermosetting adhesive may be used, but a photocurable adhesive is preferably used. As the photocurable adhesive, one containing a polymer or a reactive monomer can be used. In addition, the adhesive may contain a solvent, a photopolymerization initiator, other additives, and the like as required.

Photocurable adhesives are adhesives that can be cured when exposed to light such as visible light, ultraviolet rays, and infrared rays. Among them, an adhesive that can be cured with ultraviolet rays is preferable in terms of easy handling.

The thickness of the bonding layer is preferably 0.5 μm or more, more preferably 1 μm or more, more preferably 30 μm or less, more preferably 20 μm or less, and more preferably 10 μm or less. By setting the thickness of the bonding layer within the aforementioned range, good bonding can be achieved without impairing the optical properties of the optically anisotropic layer.

In addition, when the polarizing plate includes an optically anisotropic stack, the polarizing plate functions as a circular polarizing plate. Here, the term "circular polarizing plate" includes not only circular polarizing plate in a narrow sense, but also elliptical polarizing plate. Such a circularly polarizing plate may also include a linear polarizer, an optically anisotropic layer and a retardation layer in sequence. In addition, such a circularly polarizing plate may include a linear polarizer, a retardation layer, and an optically anisotropic layer in this order.

In the aforementioned circular polarizing plate, preferably, the angle formed by the slow axis of the retardation layer with respect to the polarization absorption axis of the linear polarizer is 45° or an angle close thereto. Specifically, the aforementioned angle is preferably 45°±5°, preferably 45°±4°, and particularly preferably 45°±3°.

The above-mentioned polarizing plate may further comprise any layered body. As an arbitrary layer body, a polarizer protective film layer is mentioned, for example. As the polarizer protective film layer, any transparent film layer may be used. Among them, the film layer of resin excellent in transparency, mechanical strength, thermal stability, moisture shielding property, etc. is preferable. Examples of such resins include acetate resins such as cellulose triacetate, polyester resins, polyether resins, polycarbonate resins, polyamide resins, polyimide resins, chain olefin resins, and cyclic olefin resins. Olefin resin, (meth)acrylic resin, etc. Furthermore, as an arbitrary layer body that the polarizing plate may contain, for example, a hard coat layer such as an impact-resistant polymethacrylic resin layer, a base layer for optimizing the smoothness of a film, a reflection suppressing layer, an antifouling layer, etc. can be mentioned. As for these arbitrary layers, only one layer may be provided, or two or more layers may be provided.

The polarizing plate can be manufactured by laminating the "linear polarizer" and "optical anisotropic layer, multi-layer for transfer, or optically anisotropic stack" by using adhesive as required.

[5. Video display device]

The image display device of the present invention includes the above-described polarizing plate of the present invention. In addition, the image display device of the present invention usually includes an image display element. In an image display device, the polarizer is usually disposed on the viewing side of the image display element. At this time, the direction of the polarizing plate can be arbitrarily set depending on the purpose of the polarizing plate. Therefore, the image display device may sequentially include: an optically anisotropic layer, a multilayer for transfer, or an optically anisotropic stack; a polarizer; and an image display element. In addition, the image display device may sequentially include: a polarizer; an optically anisotropic layer, a multilayer for transfer, or an optically anisotropic stack; and an image display element.

As an image display device, there are various types of image display elements, but typical examples include a liquid crystal display device including a liquid crystal cell as an image display element, and an organic EL display device including an organic EL element as the image display element. device.

The image display device of the present invention includes the optically anisotropic layer of the present invention as a constituent element, and thereby, the reflection of natural light can be suppressed, and the light for displaying the image can pass through the polarized sunglasses. Furthermore, while having such an effect, a display device having high durability and a favorable color tone can be produced.

"Example"

The following examples are disclosed to specifically illustrate the present invention. However, the present invention is not limited to the embodiments disclosed below, and can be arbitrarily modified and implemented within the scope of the patent application of the present invention and its equivalent scope. In the following description, "%" and "part" indicating the amount are based on weight unless otherwise noted. In addition, unless otherwise noted, the operations described below were performed in the atmosphere at normal temperature and pressure.

[Evaluation method]

[Optical properties of thin films]

Optical properties (retardation, retardation, and inverse wavelength dispersion properties) of sample layers (optically anisotropic layers, retardation layers, etc.) formed on a film (base film, etc.) were measured by the following methods.

The sample layer to be evaluated was bonded to a glass slide with an adhesive (adhesive: "CS9621T" manufactured by Nitto Denko Corporation). After that, the film was peeled off to obtain a sample including a glass slide and a sample layer. This sample was placed on a thermal stage of a phase difference meter (manufactured by Axometrics), and the wavelength dispersion of the in-plane retardation Re of the test material layer was measured. Here, the wavelength dispersion of the in-plane retardation Re is a graph showing the in-plane retardation Re per wavelength. For example, a graph is drawn on the coordinates where the horizontal axis is the wavelength and the vertical axis is the in-plane retardation Re. reveal. From the wavelength dispersion of the in-plane retardation Re of the sample layer thus obtained, the in-plane retardation Re(450), Re(550), Re(590 of the sample layer at wavelengths of 450 nm, 550 nm, 590 nm, and 650 nm were obtained. ) and Re(650).

Then, with the slow axis of the sample layer as the rotation axis, the stage was inclined at 40°, and the wavelength dispersion of the retardation Re40 of the sample layer in the inclined direction at an angle of 40° with respect to the thickness direction of the sample layer was measured. Here, the wavelength dispersion of retardation Re40 is a graph showing the in-plane retardation Re40 per wavelength, for example, it is shown as a graph on the coordinates where the horizontal axis is the wavelength and the vertical axis is the in-plane retardation Re40.

Furthermore, using a pyran coupler (manufactured by Metricon), at wavelengths of 407 nm, 532 nm, and 633 nm, the “refractive index nx belonging to the in-plane direction and the direction giving the maximum refractive index”, “the index of The refractive index ny” and “the refractive index nz of the thickness direction” in the in-plane direction and perpendicular to the direction of the aforementioned nx, and the wavelengths of the refractive indices nx, ny and nz are obtained by Cauchy fitting dispersion. Here, the wavelength dispersion of the refractive index is a graph showing the refractive index for each wavelength. For example, the horizontal axis is the wavelength and the vertical axis is the refractive index, and the graph is shown as a graph.

Then, based on the data of the retardation Re40 and the wavelength dispersion of the refractive index, the wavelength dispersion of the retardation Rth in the thickness direction of the sample layer was calculated. Here, the wavelength dispersion of the retardation Rth in the thickness direction is a graph showing the in-plane retardation Rth per wavelength. For example, in the coordinates where the horizontal axis is the wavelength and the vertical axis is the in-plane retardation Rth, Chart reveals. Then, based on the wavelength dispersion of the retardation Rth in the thickness direction of the sample layer obtained in this way, the retardation Rth(450) and Rth(550) in the thickness direction of the sample layer at wavelengths of 450 nm, 550 nm, 590 nm, and 650 nm were obtained. , Rth(590) and Rth(650).

[thickness]

The thickness of the sample layer (optically anisotropic layer, retardation layer, etc.) formed on a film (substrate film; support film; multilayer film composed of a support film and a retardation layer; etc.) is used Film thickness measurement device (“FILMETRICS” manufactured by FILMETRICS) measures.

[Haze change ratio]

Prepare flat glass with optical adhesive (CS9621 manufactured by Nitto Denko Corporation). The optically anisotropic layer of the multilayer for transfer was transferred to this plate glass to prepare a stack for haze measurement. Using this stack for haze measurement, the haze of the optically anisotropic layer was calculated by a haze meter ("Haze-gard II" manufactured by Toyo Seiki Co., Ltd., the same applies hereinafter) in accordance with JIS K 7136:2000. Haze measurement to obtain the initial haze value.

Then, the stack for haze measurement was placed in an oven and heated. The heating temperature was set at 85°C, and the heating time was set at 100 hours. After the heating, the haze was measured again with a haze meter to obtain the haze value after heating. According to the initial haze value and the haze value after heating, calculate the haze change ratio (haze value after heating/initial haze value).

[degree of cure]

The optically anisotropic layer for curing metrology was prepared by peeling the optically anisotropic layer from the substrate.

The infrared absorption spectrum of the optically anisotropic layer in the optically anisotropic layer for curing measurement was measured by the ATR method. Specifically, with an ATR measuring device (model name "Nicolet iS 5N manufactured by Thermo Fisher SCIENTIFIC"), the surface of the stack for curing measurement was measured under the condition of one reflection using ZeSe as the fluoride. The infrared absorption spectrum of the exposed optically anisotropic layer. The infrared absorption spectrum was obtained as the relationship between the wave number and the absorbance. The area of the peak appearing around 810 cm ⁻¹ was measured as A _{C - H} and the measurement appeared at The area of the peak around 1720 cm ⁻¹ is taken as A _{C = O.} In the examples and comparative examples of this application, the positive type C polymer has a C=O bond similar to C=O _MD , so it is excluded that similar Quantification of the influence of the C=O bond (Reference Example 3). Based on these measurement results, the value of A _{C - H} /A _{C = O} (a mesogen compound) was obtained.

[b ^* ]

By the same operation as the preparation of the stack for haze measurement, the optically anisotropic layer of the multilayer for transfer was transferred to flat glass to prepare a stack for hue measurement. The transmittance of this stack for hue measurement in the visible light region (380 nm to 780 nm) was measured with a spectrophotometer (“V-550” manufactured by JSCO Corporation) at 1.0 nm intervals. Based on the obtained measurement results, the hue b ^* is calculated. The observation conditions at this time were set as a field of view of 2°, a light source of D65, and a data interval of 2 nm.

[Example 1]

A solvent was prepared by mixing 1,3-dioxo (DOL) and methyl isobutyl ketone (MIBK). The mixing ratio of DOL and MIBK (DOL/MIBK, which is a weight ratio) is set at 80/20.

55 parts by weight of a photopolymerizable reverse wavelength dispersive liquid crystal compound (CN point: 96° C.) represented by the following formula (B1) as a positive type C polymer such that the solid content concentration becomes 12%. 45 parts by weight of a copolymer of diisopropyl butenedioate and cinnamic acid ester, 1.65 parts by weight of a polymerization initiator (trade name "Irgacure Oxe04", manufactured by BASF Corporation), and a crosslinking agent (trade name "A- TMPT", trimethylolpropane triacrylate, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.) 1.65 parts by weight was dissolved in a solvent to prepare a coating liquid.

"Hua 11"

The "copolymer of diisopropyl fumarate and cinnamate" used in the preparation of the coating liquid has a repeating unit represented by the following formula (P1) and a repeating unit represented by the following formula (P2). Polyfumarate of repeating units indicated (weight average molecular weight 72,000). Moreover, in following formula (P1) and formula (P2), R represents an isopropyl group, and the ratio of the number m of repeating units and n is m:n=85:15.

"Hua 12"

"Hua 13"

An unstretched film (manufactured by Zeon Corporation, Japan, glass transition temperature (Tg) of resin: 163°C, thickness: 100 μm) made of resin containing "alicyclic structure-containing polymer" was prepared as a base film. Using a coating blade, the coating liquid is coated on the surface of the aforementioned substrate film to form a coating liquid layer. The thickness of the coating liquid layer is adjusted so that the thickness of the obtained optically anisotropic layer is about 10 μm.

After that, the coating liquid layer was dried in an oven at 85° C. for 5 minutes, and the solvent in the coating liquid layer was evaporated to obtain a multilayer product having a layer structure of (dry coating liquid layer)/(substrate film).

Further, the dried coating liquid layer was irradiated with ultraviolet rays. Ultraviolet irradiation was carried out by "using an irradiation device equipped with a high-pressure mercury light source, under the conditions of an illuminance of 300 mW/cm ² and an integrated light amount of 600 mJ/cm ² , from the light source on the surface of the dry coating liquid layer of the multilayer object. UV light". By this ultraviolet irradiation, the dried coating liquid layer is cured, an optically anisotropic layer is formed, and a multilayered product for transfer having a layer structure of (optical anisotropic layer)/(substrate film) is obtained. The optical properties of the optically anisotropic layer of the obtained transfer multilayer were measured, and nx(A), ny(A), nz(A), Rth(A450)/Rth(A550), Rth( A650)/Rth(A550), Re(A590) and Rth(A590). Furthermore, the curing degree A, b ^* and the haze change ratio of the optically anisotropic layer were measured.

[Examples 2 to 4 and Comparative Examples 1 to 4]

Except having changed the integrated light amount to the value shown in Table 1, it carried out similarly to Example 1, and obtained the multilayer body for transfer, and evaluated it.

The results of Examples and Comparative Examples are summarized in Tables 1 and 2 and disclosed.

"Table 1"

"Table 2"

As is apparent from the results of the examples and comparative examples, the optically anisotropic layers of the examples having the specific curing degree A specified in the present application have less haze increase due to heating, and thus are durable. Sex is higher. In addition, it was found that the optically anisotropic layer of the examples has a b ^* value of 2.2 or less and a favorable color tone.

[Reference Example 1: Confirmation of the wavelength dispersion properties of the reverse wavelength dispersion liquid crystal compound represented by the aforementioned formula (B1)]

100 parts by weight of the photopolymerizable reverse wavelength dispersion liquid crystal compound represented by the aforementioned formula (B1), 3 parts by weight of a photopolymerization initiator (“Irgacure 379EG” manufactured by BASF Corporation), and a surfactant (manufactured by DIC Corporation) were mixed "MEGAFAC F-562") 0.3 parts by weight, and further added a mixed solvent of cyclopentanone and 1,3-dioxane (weight ratio cyclopentanone: 1,3-dioxa) so that the solid content was 22% by weight 𠷬=4:6) as a dilution solvent, and heated to 50°C to dissolve. The obtained mixture was filtered with a membrane filter having a pore size of 0.45 μm to obtain a liquid crystal composition.

Prepare an unstretched film ("ZEONOR film" manufactured by Zeon Corporation) containing a resin containing "alicyclic structure-containing polymer". By subjecting this unstretched film to a rubbing treatment, an alignment substrate is prepared.

On the aforementioned alignment substrate, a liquid crystal composition is coated with a bar coater to form a layer of the liquid crystal composition. The thickness of the layered body of the liquid crystal composition was adjusted so that the thickness of the optically anisotropic layer obtained after curing was about 2.3 μm.

After that, the layer of the liquid crystal composition was dried in an oven at 110° C. for about 4 minutes, and at the same time the solvent in the liquid crystal composition was evaporated, the reverse wavelength dispersion liquid crystal compound contained in the liquid crystal composition was uniformly aligned.

Then, ultraviolet rays were irradiated to the layered body of the liquid crystal composition using an ultraviolet irradiation apparatus. The irradiation of the ultraviolet rays was performed in a state where the alignment substrate was fixed to the SUS plate with an adhesive tape in a nitrogen atmosphere. The layered body of the liquid crystal composition was cured by irradiation with ultraviolet rays, thereby obtaining a sample film having an optically anisotropic layer and an alignment substrate.

For this sample film, the wavelength dispersion of the in-plane retardation was measured by a phase difference meter (manufactured by Axometrics). Since the alignment substrate has no in-plane retardation, the in-plane retardation obtained by the aforementioned measurement reveals the in-plane retardation of the optically anisotropic layer. As a result of the measurement, the in-plane retardations Re(450), Re(550) and Re(650) satisfy Re(450)<Re(550)<Re(650) at wavelengths of 450 nm, 550 nm and 650 nm. Therefore, it was confirmed that the photopolymerizable reverse wavelength dispersive liquid crystal compound represented by the aforementioned formula (B1) exhibits in-plane retardation of reverse wavelength dispersibility in the case of uniform alignment.

[Reference Example 2: Confirmation that the copolymer of diisopropyl fumarate and cinnamic acid ester conforms to the positive type C polymer]

A copolymer of diisopropyl fumarate and cinnamic acid ester was added to N-methylpyrrolidone so that the solid content concentration would be 12% by weight, and the polymer was obtained by dissolving it at room temperature. solution.

Prepare an unstretched film ("ZEONOR film" manufactured by Zeon Corporation) containing a resin containing "alicyclic structure-containing polymer". The aforementioned polymer solution was applied on the unstretched film using a coater to form a layer of polymer solution. After that, the solvent was evaporated by drying it in an oven at 85° C. for about 10 minutes to obtain a sample film having a polymer film having a thickness of about 10 μm and an unstretched film.

This sample film was placed on a stage of a phase difference meter (manufactured by Axometrics), and the in-plane retardation Re0 of the sample film was measured at a measurement wavelength of 590 nm. Since the unstretched film is an optically isotropic film, the measured in-plane retardation Re0 represents the in-plane retardation Re0 of the polymer film. As a result of the measurement, the in-plane retardation Re0 is Re0≦1 nm, so it can be confirmed that nx(P)≧ny(P), and these values are the same or close to each other.

Then, using the slow axis of the polymer film as the rotation axis of the stage, the stage was inclined by 40°, and the retardation Re40 in the inclined direction at an angle of 40° with respect to the thickness direction of the sample film was measured. Then, by this measurement, the slow axis direction of the polymer film is measured. If the "slow axis direction" is perpendicular to the "rotation axis of the table", it can be determined that nz(P)>nx(P), otherwise, if the "slow axis direction" is parallel to the "rotation axis of the table", it can be determined that ny(P)>nz(P). As a result of the measurement, since the slow axis direction is perpendicular to the rotation axis of the table, the refractive indices nx(P) and nz(P) of the polymer film can be determined to satisfy nz(P)>nx(P).

Therefore, it was confirmed that when a copolymer of diisopropyl fumarate and cinnamate is formed into a polymer film by a coating method using a solution of the copolymer, the refractive index of the polymer film satisfies nz(P)>nx(P)≧ny(P). Therefore, it was confirmed that the copolymer of diisopropyl fumarate and cinnamic acid ester corresponds to a normal type C polymer.

[Reference Example 3]

Except having changed the amount of the mesogen compound and the positive type C polymer in the coating liquid, the same operation as in Example 3 was carried out to obtain a plurality of multilayers for transfer. The infrared absorption spectrum of each optically anisotropic layer of the obtained multilayer for transfer was measured by the ATR method. The area of the peak appearing in the vicinity of 1720 cm ⁻¹ in the obtained infrared absorption spectrum was determined as A _{C = O} . As a result, the results shown in Table 3 were obtained. From these values, the constant a _{C = O} (mesogen compound) is calculated by the least squares method. As a result, the values of a _{C = O} (mesogen compound) = 12.93 and a _{C = O} (polymer) = 21.42 were obtained. Based on these values, the value of A _{C = O} (a mesogen compound) in the examples and comparative examples was obtained, and it was used in the calculation of the degree of curing A.

"table 3"

none.

none.

none.

Claims (15)

An optically anisotropic layer, which is an optically anisotropic layer comprising a positive-type C polymer, a mesogen compound, and a polymer of a mesogen compound, wherein the positive-type C polymer is obtained by using the positive-type C polymer. When the film of the positive type C polymer is formed by the coating method of the solution of the C polymer, the film satisfying the formula (1) is a polymer selected from the group consisting of polyvinylcarbazole, polyfumarate, and cellulose At least one polymer of the group consisting of derivatives, the proportion of the positive type C polymer in the total solid content of the optically anisotropic layer is 30% by weight or more and 60% by weight or less, and the mesogen compound is A compound having a mesogen skeleton and an acrylate structure is a compound represented by the following formula (I), and the ratio of the mesogen compound and its polymer in the total solid content of the optically anisotropic layer is 20% by weight More than or equal to 60 wt % or less, the optically anisotropic layer satisfies Formula (2) and Formula (3): nz(P)>nx(P)≧ny(P) Formula (1) nz(A)>nx(A )≧ny(A) Formula (2) 0.073<A _CH /A _C=O (Mesogen compound)<0.125 Formula (3) Wherein, nx(P), ny(P) and nz(P) are the The principal refractive indices, nx(A), ny(A) and nz(A) are the principal refractive indices of the optically anisotropic layer, A _CH is the mesogen compound in the infrared absorption spectrum of the optically anisotropic layer The infrared absorption related to the out-of-plane bending vibration of the CH bond of the aforementioned acrylate structure, A _C=O (the mesogen compound) is in the infrared absorption spectrum of the aforementioned optically anisotropic layer, the aforementioned mesogen compound of the aforementioned The infrared absorption related to the stretching vibration of the C=O bond possessed by the acrylate structure is related to the stretching vibration of the C=O bond derived from the C=O bond possessed by the aforementioned mesogen compound. The sum of infrared absorption,

(In the aforementioned formula (I): Y ¹ to Y ⁸ independently represent a chemical single bond, -O-, -S-, -OC(=O)-, -C(=O)-O-, - OC(=O)-O-, -NR ¹ -C(=O)-, -C(=O)-NR ¹ -, -OC(=O)-NR ¹ -, -NR ¹ -C(=O )-O-, -NR ¹ -C(=O)-NR ¹ -, -O-NR ¹ - or -NR ¹ -O-; here, R ¹ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms ; G ¹ and G ² independently represent a divalent aliphatic group with a carbon number of 1 to 20 that may also have a substituent; and, in the aforementioned aliphatic groups, each aliphatic group may also have more than one -O- , -S-, -OC(=O)-, -C(=O)-O-, -OC(=O)-O-, -NR ² -C(=O)-, -C(=O) -NR ² -, -NR ² - or -C(=O)-; wherein, the case where two or more -O- or -S- are adjacent to each other and intermediary is excluded; here, R ² represents a hydrogen atom or carbon number Alkyl of 1 to 6; Z ¹ and Z ² independently represent an alkenyl group with 2 to 10 carbon atoms that can also be substituted by a halogen atom; A ^x represents at least one selected from the group consisting of an aromatic hydrocarbon ring and an aromatic heterocyclic ring An organic group with 2 to 30 carbon atoms in an aromatic ring; A ^y represents a hydrogen atom, an alkyl group with 1 to 20 carbon atoms that may have a substituent, an alkenyl group with 2 to 20 carbon atoms that may have a substituent, or a Cycloalkyl having 3 to 12 carbon atoms, alkynyl having 2 to 20 carbon atoms, -C(=O)-R ³ , -SO ₂ -R ⁴ , -C(= S) NH-R ⁹ or an organic group having 2 to 30 carbon atoms in at least one aromatic ring selected from the group consisting of an aromatic hydrocarbon ring and an aromatic heterocycle; here, R ³ represents a carbon number that may also have a substituent 1 to 20 alkyl groups, alkenyl groups with 2 to 20 carbon atoms that can also have substituents, cycloalkyl groups with 3 to 12 carbon atoms that can also have substituents, or aromatic hydrocarbon ring groups with 5 to 12 carbon atoms; R ⁴ Represents an alkyl group with 1 to 20 carbon atoms, an alkenyl group with 2 to 20 carbon atoms, a phenyl group or 4-methylphenyl group; R ⁹ represents an alkyl group with 1 to 20 carbon atoms that may have a substituent, or an alkyl group with a carbon number of 1 to 20. The alkenyl group with 2 to 20 carbon atoms of the substituent, the cycloalkyl group with 3 to 12 carbon atoms that can also have a substituent, or the ^aryl group with 5 to 20 carbon atoms that can also have a ^substituent ; The aromatic ring it has may also have a substituent; and the aforementioned A ^x and A ^y may also be combined to form a ring; A ¹ represents a trivalent aryl group that may also have a substituent; A ² and A ³ independently represent that a substituent may also be available. A divalent alicyclic hydrocarbon group with 3 to 30 carbon atoms in the base; A ⁴ and A ⁵ independently represent a divalent aryl group with a carbon number of 6 to 30 that may have a substituent; Q ¹ represents a hydrogen atom or a substituent The alkyl group of carbon number 1~6; m and n independently represent 0 or 1; wherein, one or both of Z ¹ -Y ⁷ - and -Y ⁸ -Z ² is propyl alkenyloxy). The optically anisotropic layer according to claim 1, wherein the aforementioned mesogen compound is a compound that exhibits in-plane retardation of reverse wavelength dispersion in the case of uniform alignment. The optically anisotropic layer according to claim 1 or 2, which satisfies formula (4) and formula (5): 0.50<Rth(A450)/Rth(A550)<1.00 Formula (4) 1.00≦Rth(A650) /Rth(A550)<1.25 Equation (5) where Rth(A450) is the retardation of the optically anisotropic layer in the thickness direction at a wavelength of 450nm, and Rth(A550) is the thickness direction of the optically anisotropic layer at a wavelength of 550nm The retardation, Rth(A650) is the retardation of the aforementioned optically anisotropic layer in the thickness direction at a wavelength of 650 nm. The optically anisotropic layer according to claim 1 or 2, wherein the mesogen compound contains, in its molecular structure, at least one selected from the group consisting of a benzothiazole ring and a combination of a cyclohexyl ring and a benzene ring . The optically anisotropic layer according to claim 1 or 2, which satisfies formula (6) and formula (7): Re(A590)≦10nm formula (6) -200nm≦Rth(A590)≦-10nm formula (7) ) wherein Re(A590) is the in-plane retardation of the optically anisotropic layer at a wavelength of 590 nm, and Rth(A590) is the retardation of the optically anisotropic layer in the thickness direction at a wavelength of 590 nm. A multi-layer for transfer, comprising a base material and the optically anisotropic layer according to any one of claims 1 to 5. An optically anisotropic stack comprising the optically anisotropic layer and the retardation layer according to any one of claims 1 to 5, wherein the retardation layer satisfies the formula (8): nx(B)>ny( B)≧nz(B) In the formula (8), nx(B), ny(B) and nz(B) are the principal refractive indices of the retardation layer. The optically anisotropic stack according to claim 7, wherein the aforementioned retardation layer satisfies the formula (9) and the formula (10): 0.75<Re(B450)/Re(B550)<1.00 formula (9) 1.01<Re (B650)/Re(B550)<1.25 Formula (10) Among them, Re(B450) is the in-plane retardation of the aforementioned retardation layer at a wavelength of 450 nm, Re(B550) is the in-plane retardation of the aforementioned retardation layer at a wavelength of 550 nm, and Re(B650) is the aforementioned retardation layer at a wavelength of 650 nm. internal delay. The optically anisotropic stack according to claim 8, wherein the aforementioned retardation layer comprises a liquid crystal compound for a retardation layer represented by the following formula (II):

(In the aforementioned formula (II): Y ¹ to Y ⁸ independently represent a chemical single bond, -O-, -S-, -OC(=O)-, -C(=O)-O-, - OC(=O)-O-, -NR ¹ -C(=O)-, -C(=O)-NR ¹ -, -OC(=O)-NR ¹ -, -NR ¹ -C(=O )-O-, -NR ¹ -C(=O)-NR ¹ -, -O-NR ¹ - or -NR ¹ -O-; here, R ¹ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms ; G ¹ and G ² independently represent a divalent aliphatic group with a carbon number of 1 to 20 that may also have a substituent; and, in the aforementioned aliphatic groups, each aliphatic group may also have more than one -O- , -S-, -OC(=O)-, -C(=O)-O-, -OC(=O)-O-, -NR ² -C(=O)-, -C(=O) -NR ² -, -NR ² - or - C(=O)-; wherein, the case where two or more -O- or -S- are adjacent to each other and intermediary is excluded; here, R ² represents a hydrogen atom or carbon number Alkyl of 1 to 6; Z ¹ and Z ² independently represent an alkenyl group with 2 to 10 carbon atoms that can also be substituted by halogen atoms; A ^x represents at least one selected from the group consisting of aromatic hydrocarbon rings and aromatic heterocycles An organic group with 2 to 30 carbon atoms in an aromatic ring; A ^y represents a hydrogen atom, an alkyl group with 1 to 20 carbon atoms that may have a substituent, an alkenyl group with 2 to 20 carbon atoms that may have a substituent, or a Cycloalkyl having 3 to 12 carbon atoms, alkynyl having 2 to 20 carbon atoms, -C(=O)-R ³ , -SO ₂ -R ⁴ , -C(= S) NH-R ⁹ or an organic group having 2 to 30 carbon atoms in at least one aromatic ring selected from the group consisting of aromatic hydrocarbon rings and aromatic heterocycles; here, R ³ represents a carbon number that may also have a substituent 1 to 20 alkyl groups, alkenyl groups with 2 to 20 carbon atoms that can also have substituents, cycloalkyl groups with 3 to 12 carbon atoms that can also have substituents, or aromatic hydrocarbon ring groups with 5 to 12 carbon atoms; R ⁴ Represents an alkyl group with 1 to 20 carbon atoms, an alkenyl group with 2 to 20 carbon atoms, a phenyl group or 4-methylphenyl group; R ⁹ represents an alkyl group with 1 to 20 carbon atoms that may have a substituent, or an alkyl group with a carbon number of 1 to 20. The alkenyl group with 2 to 20 carbon atoms of the substituent, the cycloalkyl group with 3 to 12 carbon atoms that can also have a substituent, or the ^aryl group with 5 to 20 carbon atoms that can also have a ^substituent ; The aromatic ring it has may also have a substituent; and the aforementioned A ^x and A ^y may also be combined to form a ring; A ¹ represents a trivalent aryl group that may also have a substituent; A ² and A ³ independently represent that a substituent may also be available. A divalent alicyclic hydrocarbon group with 3 to 30 carbon atoms in the base; A ⁴ and A ⁵ independently represent a divalent aryl group with 6 to 30 carbon atoms that can also have a substituent; Q ¹ represents a hydrogen atom or a substituent. The alkyl group of carbon number 1~6; m and n independently represent 0 or 1). A polarizing plate comprising: a linear polarizer; and the optically anisotropic layer as described in any one of claims 1 to 5, the multi-layer for transfer as described in claim 6, or the optically anisotropic layer as described in claim 7 to 9 The optically anisotropic stack of any one. An image display device including the polarizing plate according to claim 10. An image display device, comprising in sequence: the optically anisotropic stack according to any one of claims 7 to 9; a linear polarizer; and an image display element; the image display element is a liquid crystal cell or an organic electro-optical element light-emitting element. A method for producing an optically anisotropic layer as claimed in any one of claims 1 to 5, comprising: preparing a composition comprising a positive type C polymer, a mesogen compound, a solvent, a photopolymerization initiator and a crosslinking agent the process of coating liquid; the process of applying the above-mentioned coating liquid on the support surface to obtain a coating liquid layer; and A step of curing the coating liquid layer by irradiating the coating liquid layer with light. The method for producing an optically anisotropic layer according to claim 13, wherein in the coating solution, the ratio of the photopolymerization initiator to 100 parts by weight of the mesogen compound is 1 part by weight to 10 parts by weight, and the above The ratio of the crosslinking agent to 100 parts by weight of the aforementioned mesogen compound is 1 part by weight to 10 parts by weight. The manufacturing method according to claim 13 or 14, wherein the integrated light amount of the irradiated light is 600 mJ/cm ² to 5000 mJ/cm ² .