JP7356480B2 - Optical film and its manufacturing method - Google Patents

Description

The present invention relates to an optical film and a method for manufacturing the same.

Optical films such as polarizing plates and retardation plates are used in flat panel display devices (FPDs). Retardation plates are required to have uniform phase conversion over the entire visible light range; for example, Patent Document 1 discloses a reverse wavelength dispersion retardation film oriented in the horizontal direction, and Patent Document 2 discloses a reverse wavelength dispersion retardation film oriented in the vertical direction. A reverse wavelength dispersion retardation film is disclosed.

Special Publication No. 2010-537955 Japanese Patent Application Publication No. 2015-57646

In recent years, with the evolution of flat panel displays, there has been a demand for clear black display from any direction. Accordingly, it has become clear that controlling optical wavelength dispersion in the horizontal or vertical direction alone is insufficient.

The present invention includes the following inventions.

[1] An optical film that has a first retardation layer and a second retardation layer and satisfies the relationships of formulas (1) and (2) below.
0.4≦Nz(450)≦0.6 (1)
0.4≦Nz(550)≦0.6 (2)
[In the formula, Nz (450) represents the Nz coefficient of the optical film for light with wavelength λ = 450 nm, Nz (550) represents the Nz coefficient of the optical film for light with wavelength λ = 550 nm, and The Nz coefficient Nz (λ) of the optical film for light is Nz (λ) = (nx (λ) - nz (λ)) / (nx (λ) - ny (λ))
It is shown by. nx (λ) represents the principal refractive index in a direction parallel to the film plane for light with a wavelength λ (nm) in the refractive index ellipsoid formed by the optical film. ny (λ) is the refraction of light of wavelength λ (nm) in a direction parallel to the film plane and orthogonal to the direction of nx (λ) in the index ellipsoid formed by the optical film. represents the rate.
nz (λ) represents the refractive index in the direction perpendicular to the film plane for light with a wavelength λ (nm) in the refractive index ellipsoid formed by the optical film. ]

[2] The first retardation layer is
In the range of wavelength λ = 400 to 700 nm in the refractive index ellipsoid formed by the first retardation layer,
nx1(λ)>ny1(λ)≒nz1(λ)
[In the formula, nx1 (λ) represents the principal refractive index in the direction parallel to the film plane for light of wavelength λ (nm) in the refractive index ellipsoid formed by the first retardation layer. ny1 (λ) is a wavelength λ (nm) in a direction parallel to the film plane and orthogonal to the direction of nx1 (λ) in the refractive index ellipsoid formed by the first retardation layer. represents the refractive index for light. nz1 (λ) represents the refractive index in the direction perpendicular to the film plane for light with wavelength λ (nm) in the refractive index ellipsoid formed by the first retardation layer. ]
have the relationship of
The optical film according to [1] above, which satisfies the relationships of formulas (3) and (4) below.
Re1(450)/Re1(550)≦1.00 (3)
1.00≦Re1(650)/Re1(550) (4)
[In the formula, Re1 (450) is the in-plane retardation value of the first retardation layer for light with a wavelength λ = 450 nm, and Re1 (550) is the in-plane retardation value of the first retardation layer for light with a wavelength λ = 550 nm. Re1 (650) indicates the in-plane retardation value of the first retardation layer for light with a wavelength λ = 650 nm, and Re1 (650) indicates the in-plane retardation value of the first retardation layer for light with a wavelength λ nm. The value Re1(λ) is
Re1(λ)=(nx1(λ)−ny1(λ))×d1
It is expressed as Here, d1 represents the thickness of the first retardation layer. ]

[3] The second retardation layer is
In the range of wavelength λ = 400 to 700 nm in the refractive index ellipsoid formed by the second retardation layer,
nz2(λ)>nx2(λ)≒ny2(λ)
[In the formula, nz2 (λ) represents the refractive index in the direction perpendicular to the film plane for light with a wavelength λ (nm) in the refractive index ellipsoid formed by the second retardation layer. nx2(λ) represents the principal refractive index in the direction parallel to the film plane for light of wavelength λ (nm) in the refractive index ellipsoid formed by the second retardation layer. ny2 (λ) is the refractive index ellipsoid formed by the second retardation layer, which is parallel to the film plane and perpendicular to the direction of nx2 for light of wavelength λ (nm). Represents refractive index. However, when nx2(λ)=ny2(λ), nx2(λ) represents the refractive index in any direction parallel to the film plane. ]
have the relationship of
The optical film described in [1] or [2] above, which satisfies the relationships of formulas (5) and (6) below.
Rth2(450)/Rth2(550)≦1.00 (5)
1.00≦Rth2(650)/Rth2(550) (6)
[In the formula, Rth2 (450) is the retardation value in the thickness direction of the second retardation layer for light with a wavelength λ = 450 nm, and Rth2 (550) is the retardation value of the second retardation layer for light with a wavelength λ = 550 nm. Rth2 (650) represents the retardation value in the thickness direction of the second retardation layer for light with a wavelength of 650 nm, and Rth2 (650) represents the retardation value of the second retardation layer in the thickness direction for light with a wavelength of λ (nm). The retardation value Rth2(λ) in the thickness direction is
Rth2(λ)=[(nx2(λ)+ny2(λ))/2-nz2(λ)]×d2
It is expressed as Here, in the refractive index ellipsoid formed by the second retardation layer, nz2 (λ) represents the principal refractive index in the direction perpendicular to the film plane at the wavelength λ (nm), and ((nx2 (λ) + ny2 (λ))/2) represents the average refractive index at the film plane at wavelength λ (nm). d2 represents the thickness of the second retardation layer. ]

[4] The optical film according to any one of [1] to [3] above, wherein the first retardation layer further satisfies the relationship of formula (7) below.
120nm≦Re1(550)≦170nm (7)
[In the formula, Re1 (550) represents the in-plane retardation value of the first retardation layer for light with a wavelength λ=550 nm. ]

[5] The optical film according to any one of [1] to [4] above, wherein the second retardation layer further has optical properties represented by formula ( 8 ).
-100nm≦Rth2(550)≦-50nm (8)
[In the formula, Rth2 (550) represents the retardation value in the thickness direction of the second retardation layer with respect to light with a wavelength λ=550 nm. ]

[6] The optical film according to any one of [1] to [5] above, wherein the second retardation layer is a film consisting of a coating layer formed by polymerizing polymerizable liquid crystal in an oriented state.

[7] The optical film according to any one of [1] to [6] above, wherein the first retardation layer is a film consisting of a coating layer formed by polymerizing polymerizable liquid crystal in an oriented state.

[8] The optical film according to any one of [1] to [7] above, wherein the second retardation layer has a thickness of 5 μm or less.

[9] The optical film according to any one of [1] to [8] above, wherein the first retardation layer has a thickness of 5 μm or less.

[10] The first retardation layer and the second retardation layer are coating layers formed by mainly polymerizing the same polymerizable liquid crystal compound, according to any one of [1] to [9] above. optical film.

[11] An elliptically polarizing plate with an optical compensation function, comprising the optical film according to any one of [1] to [10] above and a polarizing plate.

[12] The absorption axis of the polarizing plate and the slow axis of the first retardation layer have a relationship of 45±5° or 135±5° in the film plane, and the absorption axis of the polarizing plate and the slow axis of the first retardation layer The elliptically polarizing plate with an optical compensation function according to [11] above, wherein the slow axis of the retardation layer and the slow axis of the second retardation layer are perpendicular to the film surface in a direction perpendicular to the film surface.

[13] The optical laminate described in [11] or [12] above, which is an optical laminate in which a polarizing plate, an adhesive layer, a first retardation layer, an adhesive layer, and a second retardation layer are formed in this order. Elliptical polarizing plate with optical compensation function.

[14] The optical laminate described in [11] or [12] above, which is an optical laminate in which a polarizing plate, an adhesive layer, a second retardation layer, an adhesive layer, and a first retardation layer are formed in this order. Elliptical polarizing plate with optical compensation function.

An organic EL display device comprising the elliptically polarizing plate with an optical compensation function according to any one of [11] to [14] above.

The method for producing an elliptically polarizing plate with an optical compensation function according to any one of [11] to [14] above, which includes all of the following steps.
(Step 1-A) A step of forming a first retardation layer by coating a polymerizable liquid crystal compound on the base material on which the horizontal alignment film is formed and then polymerizing it in a horizontally aligned state;
(Step 1-B) A step of forming a second retardation layer by coating a polymerizable liquid crystal compound on the base material on which the vertical alignment film is formed and then polymerizing it in a vertically aligned state;
(Step 2) Step of transferring the liquid crystal polymer of the first retardation layer and the liquid crystal polymer of the second retardation layer from the base material through an adhesive and laminating them on the polarizing plate.

According to the present invention, there is provided a novel optical film whose optical refractive index is controlled in three-dimensional directions over the entire visible light range and in all visually recognized directions, and a method for manufacturing the same. Furthermore, by using this optical film, a liquid crystal display device and an organic EL display device are provided which enable clear display.

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

The optical film of the present invention consists of a first retardation layer and a second retardation layer. The first retardation layer and the second retardation layer may be formed by stretching or shrinking a polymer film. ) is preferably formed by a coating layer formed by coating and polymerizing in an oriented state.

The first retardation layer and the second retardation layer are formed by coating a composition containing a polymerizable liquid crystal compound (hereinafter also referred to as "composition for forming a retardation layer") on a transparent substrate. However, it is preferable to form a polymer in an oriented state of the polymerizable liquid crystal compound by heating and cooling treatment, since this allows thinning and arbitrary design of wavelength dispersion characteristics. Further, as described below, the composition for forming a retardation layer may further contain a solvent, a photopolymerization initiator, a photosensitizer, a polymerization inhibitor, a leveling agent, an adhesion improver, and the like.

The first retardation layer is preferably a cured liquid crystal film in which the polymerizable liquid crystal compound is oriented horizontally with respect to the substrate surface, and the second retardation layer is a liquid crystal cured film in which the polymerizable liquid crystal compound is oriented horizontally with respect to the substrate surface. It is preferable that the cured liquid crystal film be cured in a state of being oriented in a direction perpendicular to the surface.

In the first retardation layer, it is preferable that Re1 (550), which is an in-plane retardation value for light with a wavelength of 550 nm, satisfies the optical property shown in the following formula (7). In addition, the first retardation layer has an in-plane retardation value Re1 (450) for light with a wavelength of 450 nm, a Re1 (550) in-plane retardation value for light with a wavelength of 550 nm, and an in-plane retardation value for light with a wavelength of 650 nm. It is also preferable that Re1 (650), which is the internal retardation value, satisfies the optical characteristics shown by equations (3) and (4). It is more preferable that the first retardation layer satisfies the optical characteristics shown by the following formula (7), the following formula (3), and the following formula (4).
120nm≦Re1(550)≦170nm…(7)
(In the formula, Re1 (550) represents the in-plane retardation value (in-plane retardation) of the first retardation layer for light with a wavelength of 550 nm.)
Re1(450)/Re1(550)≦1.0…(3)
1.00≦Re1(650)/Re1(550)...(4)
(In the formula, Re1 (450) is the in-plane retardation value of the first retardation layer for light with a wavelength of 450 nm, and Re1 (550) is the in-plane retardation value of the first retardation layer for light with a wavelength of 550 nm. , Re1 (650) represents the in-plane retardation value of the first retardation layer for light with a wavelength of 650 nm.)
If the in-plane retardation value Re1 (550) of the first retardation layer exceeds the range of equation (7), a problem may arise in which the front hue becomes red or blue. A more preferable range of the in-plane retardation value is 130 nm≦Re1(550)≦160 nm. When "Re1 (450)/Re1 (550)" of the first retardation layer exceeds 1.0, light leakage on the short wavelength side in the elliptically polarizing plate including the retardation layer increases. Preferably it is 0.75 or more and 0.92 or less, more preferably 0.77 or more and 0.87 or less, and even more preferably 0.79 or more and 0.85 or less.

The in-plane retardation value of the first retardation layer can be adjusted by adjusting the thickness of the retardation layer. Since the in-plane retardation value is determined by the following formula (A), the desired in-plane retardation value (Re1 (λ): in-plane retardation value of the first retardation layer at wavelength λ (nm)) In order to obtain this, the three-dimensional refractive index and the film thickness d1 may be adjusted. The thickness of the retardation layer is preferably 0.5 μm to 5 μm, more preferably 1 μm to 3 μm. The thickness of the retardation layer can be measured using an interference thickness meter, a laser microscope, or a stylus thickness meter. Note that the three-dimensional refractive index depends on the molecular structure and orientation state of the polymerizable liquid crystal compound, which will be described later.
Re1 (λ) = (nx1 (λ) - ny1 (λ)) × d1 (A)
(In the formula, the refractive index ellipsoid formed by the first retardation layer has the relationship nx1 (λ) > ny1 (λ) ≒ nz1 (λ), where nx1 (λ) is the light of wavelength λ (nm). represents the principal refractive index in the direction parallel to the film plane.ny1(λ) is the principal refractive index in the direction parallel to the film plane in the refractive index ellipsoid formed by the first retardation layer for light with wavelength λ (nm). (d1 represents the thickness of the first retardation layer.)

In the second retardation layer, it is preferable that Rth2(λ), which is a retardation value in the thickness direction with respect to light having a wavelength of λnm, satisfies the optical property shown in the following formula (8). Further, it is also preferable that the optical properties shown in the following formulas (5) and (6) are satisfied. More preferably, the second retardation layer satisfies the optical characteristics expressed by the following formula (8), the following formula (5), and the following formula (6).
-100nm≦Rth2(550)≦-50nm...(8)
(In the formula, Rth2 (550) represents the retardation value in the thickness direction for light with a wavelength of 550 nm.)
Rth2(450)/Rth2(550)≦1.0…(5)
1.00≦Rth2(650)/Rth2(550)...(6)
(In the formula, Rth2 (450) is the retardation value in the thickness direction for light with a wavelength of 450 nm, Rth2 (550) has the same meaning as above, and Rth2 (650) is the retardation value in the thickness direction for light with a wavelength of 650 nm. (Represented respectively.)
If the retardation value Rth2 (550) in the thickness direction of the second retardation layer exceeds the range of equation (8), a problem may arise in which the oblique hue becomes red or blue. A more preferable range of the retardation value in the thickness direction is -95 nm≦Rth2(550)≦−55 nm, and a still more preferable range is −90 nm≦Rth2(550)≦−60 nm. When "Rth2(450)/Rth2(550)" of the second retardation layer exceeds 1.0, light leakage on the short wavelength side in the elliptically polarizing plate including the retardation layer increases. Preferably it is 0.75 or more and 0.92 or less, more preferably 0.77 or more and 0.87 or less, and even more preferably 0.79 or more and 0.85 or less.

The retardation value in the thickness direction of the second retardation layer can be adjusted by the thickness of the retardation layer. Since the in-plane retardation value is determined by the following formula (B), the desired thickness direction retardation value (Rth2(λ): in-plane retardation value of the second retardation layer at wavelength λ (nm) ) can be obtained by adjusting the three-dimensional refractive index and the film thickness d2. The thickness of the retardation layer is preferably 0.2 μm to 5 μm, more preferably 0.5 μm to 2 μm. The thickness of the retardation layer can be measured using an interference thickness meter, a laser microscope, or a stylus thickness meter. Note that the three-dimensional refractive index depends on the molecular structure and orientation of the polymerizable liquid crystal compound, which will be described later.
Rth2(λ)=[(nx2(λ)+ny2(λ))/2-nz2(λ)]×d2 (B)
(In the formula, the refractive index ellipsoid formed by the second retardation layer has the relationship nz2(λ)>nx2(λ)≒ny2(λ), where nz2(λ) is the second position. In the refractive index ellipsoid formed by the retardation layer, it represents the refractive index in the direction perpendicular to the film plane for light with wavelength λ (nm). nx2 (λ) is the refractive index ellipsoid formed by the second retardation layer In the body, it represents the principal refractive index in the direction parallel to the film plane for light with wavelength λ (nm). ny2 (λ) is the principal refractive index parallel to the film plane in the refractive index ellipsoid formed by the second retardation layer. represents the refractive index for light of wavelength λ (nm) in a direction parallel to the direction of nx2 and perpendicular to the direction of nx2.However, when nx2(λ)=ny2(λ), nx2 (λ) represents the refractive index in any direction parallel to the film plane. Here, d2 represents the thickness of the second retardation layer.)

The optical film of the present invention has a first retardation layer and a second retardation layer, and satisfies the relationships of formulas (1) and (2) below.
0.40≦Nz(450)≦0.60 (1)
0.40≦Nz(550)≦0.60 (2)
(In the formula, Nz(λ) is the Nz coefficient that indicates the relationship between the three-dimensional refractive index for light with wavelength λ (nm), and Nz(λ) = (nx(λ) - nz(λ))/(nx( λ) - ny(λ)). nx(λ) represents the principal refractive index in the direction parallel to the film plane for light with wavelength λ (nm) in the refractive index ellipsoid formed by the optical film. .ny(λ) is the direction parallel to the film plane for light of wavelength λ(nm) and orthogonal to the direction of nx(λ) in the refractive index ellipsoid formed by the optical film. Represents the refractive index. nz (λ) represents the refractive index in the direction perpendicular to the film plane for light with wavelength λ (nm) in the refractive index ellipsoid formed by the optical film.)
In other words, the optical film of the present invention has a three-dimensional refractive index relationship of nx(λ)>nz(λ)>ny(λ), and since the optical film has the relationships of formulas (1) and (2), , it is possible to provide excellent display characteristics of hue when mounted on a display. More preferably, Nz(λ) satisfies 0.45≦Nz(450)≦0.55 and 0.45≦Nz(550)≦0.55, respectively. Here, Nz (450) represents the Nz coefficient at wavelength λ = 450 nm, and Nz (550) represents the Nz coefficient at wavelength λ = 550 nm.

The Nz coefficient (Nz coefficient: Nz(λ)) indicating the relationship between nx(λ), ny(λ), and nz(λ) at each wavelength λ(nm) of the optical film is calculated by the following formula.
Nz(λ)=(nx(λ)-nz(λ))/(nx(λ)-ny(λ))
In addition, when calculating the Nz coefficient of the optical film, if the front retardation value and the thickness direction retardation value of the first retardation layer and the second retardation layer are known, the following formula (C ) can also be calculated.
Nz(λ)=(Rth1(λ)+Rth2(λ))/(Re1(λ)+Re2(λ))+0.5 (C)
(In the formula, Re1 (λ) is the front retardation value of the first retardation layer at the wavelength λ (nm), and Re2 (λ) is the front position of the second retardation layer at the wavelength λ (nm). Rth1 (λ) is the retardation value in the thickness direction of the first retardation layer at wavelength λ (nm), and Rth2 (λ) is the retardation value of the second retardation layer at wavelength λ (nm). (This is the phase difference value in the thickness direction.)

[Polymerizable liquid crystal]
The polymerizable liquid crystal compound is a liquid crystal compound having a polymerizable functional group, particularly a photopolymerizable functional group. The photopolymerizable functional group refers to a group that can participate in a polymerization reaction by active radicals, acids, etc. generated from a photopolymerization initiator. Examples of the photopolymerizable functional group include vinyl group, vinyloxy group, 1-chlorovinyl group, isopropenyl group, 4-vinylphenyl group, acryloyloxy group, methacryloyloxy group, oxiranyl group, oxetanyl group, and the like. Among these, acryloyloxy group, methacryloyloxy group, vinyloxy group, oxiranyl group and oxetanyl group are preferred, and acryloyloxy group is more preferred. The liquid crystal may be thermotropic liquid crystal or lyotropic liquid crystal, but thermotropic liquid crystal is preferable because it allows precise control of the film thickness. Further, the phase ordered structure of the thermotropic liquid crystal may be either a nematic liquid crystal or a smectic liquid crystal.

In the present invention, the structure of the following formula (I) is particularly preferable as the polymerizable liquid crystal compound since it exhibits the above-mentioned reverse wavelength dispersion.

In formula (I), Ar represents a divalent aromatic group which may have a substituent. The aromatic group referred to herein is a group having a planar cyclic structure, and the number of π electrons in the ring structure is [4n+2] according to Huckel's rule. Here n represents an integer. In the case where a ring structure is formed containing heteroatoms such as -N= and -S-, it also satisfies Huckel's rule including non-covalently bonded electron pairs on these heteroatoms and has aromaticity. Preferably, the divalent aromatic group contains at least one of a nitrogen atom, an oxygen atom, and a sulfur atom.
G ¹ and G ² each independently represent a divalent aromatic group or a divalent alicyclic hydrocarbon group. Here, the hydrogen atom contained in the divalent aromatic group or divalent alicyclic hydrocarbon group is a halogen atom, an alkyl group having 1 to 4 carbon atoms, a fluoroalkyl group having 1 to 4 carbon atoms, or a fluoroalkyl group having 1 to 4 carbon atoms. The carbon atoms constituting the divalent aromatic group or divalent alicyclic hydrocarbon group may be substituted with 1 to 4 alkoxy groups, cyano groups, or nitro groups, and oxygen atoms, sulfur atoms Alternatively, it may be substituted with a nitrogen atom.
L ¹ , L ² _, B ¹ and B ² are each independently a single bond or a divalent linking group.
k and l each independently represent an integer from 0 to 3, and satisfy the relationship 1≦k+l. Here, when 2≦k+l, B ¹ and B ² and G ¹ and G ² may be the same or different from each other.
E ¹ and E ² each independently represent an alkanediyl group having 1 to 17 carbon atoms, where the hydrogen atom contained in the alkanediyl group may be substituted with a halogen atom, and the alkanediyl group The -CH ₂ - contained therein may be substituted with -O-, -S-, or -Si-. P ¹ and P ² each independently represent a polymerizable group or a hydrogen atom, and at least one of them is a polymerizable group.

G ¹ and G ² are each independently preferably a 1,4-phenylenediyl group optionally substituted with at least one substituent selected from the group consisting of a halogen atom and an alkyl group having 1 to 4 carbon atoms. , a 1,4-cyclohexanediyl group optionally substituted with at least one substituent selected from the group consisting of a halogen atom and an alkyl group having 1 to 4 carbon atoms, and more preferably a 1,4-cyclohexanediyl group substituted with a methyl group. ,4-phenylenediyl group, unsubstituted 1,4-phenylenediyl group, or unsubstituted 1,4-trans-cyclohexanediyl group, particularly preferably unsubstituted 1,4-phenylenediyl group or unsubstituted It is a substituted 1,4-trans-cyclohexanediyl group.
Further, at least one of the plurality of G ¹ and G ² is preferably a divalent alicyclic hydrocarbon group, and at least one of G ¹ and G ² bonded to L ¹ or L ² More preferably, one is a divalent alicyclic hydrocarbon group.

L ¹ and L ² are each independently preferably a single bond, an alkylene group having 1 to 4 carbon atoms, -O-, -S-, -R ^a1 OR ^a2 -, -R ^a3 COOR ^a4 -, -R ^a5 OCOR ^a6 -, R ^a7 OC=OOR ^a8 -, -N=N-, -CR ^c =CR ^d -, or -C≡C-. Here, R ^a1 to R ^a8 each independently represent a single bond or an alkylene group having 1 to 4 carbon atoms, and R ^c and R ^d represent an alkyl group having 1 to 4 carbon atoms or a hydrogen atom. L ¹ and L ² are each independently more preferably a single bond, -OR ^a2-1 -, -CH ₂ -, -CH ₂ CH ₂ -, -COOR ^a4-1 -, or -OCOR ^a6-1 - be. Here, R ^a2-1 , R ^a4-1 , and R ^a6-1 each independently represent a single bond, -CH ₂ -, or -CH ₂ CH ₂ -. L ¹ and L ² are each independently more preferably a single bond, -O-, -CH ₂ CH ₂ -, -COO-, -COOCH ₂ CH ₂ -, or -OCO-.

B ¹ and B ² are each independently preferably a single bond, an alkylene group having 1 to 4 carbon atoms, -O-, -S-, -R ^a9 OR ^a10 -, -R ^a11 COOR ^a12 -, -R ^a13 OCOR ^a14 -, or R ^a15 OC=OOR ^a16 -. Here, R ^a9 to R ^a16 each independently represent a single bond or an alkylene group having 1 to 4 carbon atoms. B ¹ and B ² are each independently more preferably a single bond, -OR ^a10-1 -, -CH ₂ -, -CH ₂ CH ₂ -, -COOR ^a12-1 -, or -OCOR ^a14-1 - be. Here, R ^a10-1 , R ^a12-1 , and R ^a14-1 each independently represent a single bond, -CH ₂ -, or -CH ₂ CH ₂ -. B ¹ and B ² are each independently, more preferably, a single bond, -O-, -CH ₂ CH ₂ -, -COO-, -COOCH ₂ CH ₂ -, -OCO-, or -OCOCH ₂ CH ₂ -, It is.

k and l preferably have a range of 2≦k+l≦6 from the viewpoint of expressing reverse wavelength dispersion, preferably k+l=4, and more preferably k=2 and l=2. It is more preferable that k=2 and l=2 because a symmetrical structure is obtained.

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

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

Ar preferably has at least one selected from an aromatic hydrocarbon ring which may have a substituent, an aromatic heterocycle which may have a substituent, and an electron-withdrawing group. Examples of the aromatic hydrocarbon ring include a benzene ring, a naphthalene ring, an anthracene ring, and the like, with benzene rings and naphthalene rings being preferred. The aromatic heterocycles include a furan ring, a benzofuran ring, a pyrrole ring, an indole ring, a thiophene ring, a benzothiophene ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a triazole ring, a triazine ring, a pyrroline ring, an imidazole ring, and a pyrazole ring. , thiazole ring, benzothiazole ring, thienothiazole ring, oxazole ring, benzoxazole ring, and phenanthroline ring. Among these, it is preferable to have a thiazole ring, benzothiazole ring, or benzofuran ring, and more preferably to have a benzothiazole group. Further, when Ar includes a nitrogen atom, it is preferable that the nitrogen atom has π electrons.

In formula (I), the total number N _π of π electrons contained in the divalent aromatic group represented by Ar is preferably 8 or more, more preferably 10 or more, still more preferably 14 or more, and especially Preferably it is 16 or more. Further, it is preferably 30 or less, more preferably 26 or less, and still more preferably 24 or less.

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

In formulas (Ar-1) to (Ar-22), the mark * represents a connecting part, and Z ⁰ , Z ¹ and Z ² each independently represent a hydrogen atom, a halogen atom, or an alkyl group having 1 to 12 carbon atoms. group, cyano group, nitro group, alkylsulfinyl group having 1 to 12 carbon atoms, alkylsulfonyl group having 1 to 12 carbon atoms, carboxyl group, fluoroalkyl group having 1 to 12 carbon atoms, alkoxy group having 1 to 6 carbon atoms, Alkylthio group having 1 to 12 carbon atoms, N-alkylamino group having 1 to 12 carbon atoms, N,N-dialkylamino group having 2 to 12 carbon atoms, N-alkylsulfamoyl group having 1 to 12 carbon atoms, or carbon Represents an N,N-dialkylsulfamoyl group having numbers 2 to 12.

Q ¹ , Q ² and Q ³ each independently represent -CR ^2' R ^3' -, -S-, -NH-, -NR ^2' -, -CO- or -O-, and R ^2' and R ^3' each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

J ¹ and J ² each independently represent a carbon atom or a nitrogen atom.

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

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

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

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

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

Q ¹ , Q ² and Q ³ are preferably -NH-, -S-, -NR ^2' -, -O-, and R ^2' is preferably a hydrogen atom. Among them, -S-, -O-, and -NH- are particularly preferred.

Among formulas (Ar-1) to (Ar-22), formulas (Ar-6) and (Ar-7) are preferred from the viewpoint of molecular stability.
In formulas (Ar-16) to (Ar-22), Y ¹ may form an aromatic heterocyclic group together with the nitrogen atom to which it is bonded and Z ⁰ . Examples of the aromatic heterocyclic group include those mentioned above as aromatic heterocycles that Ar may have, such as a pyrrole ring, an imidazole ring, a pyrroline ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, and an indole ring. ring, quinoline ring, isoquinoline ring, purine ring, pyrrolidine ring, etc. This aromatic heterocyclic group may have a substituent. Further, Y ¹ may be the aforementioned optionally substituted polycyclic aromatic hydrocarbon group or polycyclic aromatic heterocyclic group, together with the nitrogen atom to which it is bonded and Z ⁰ . Examples include a benzofuran ring, a benzothiazole ring, a benzoxazole ring, and the like.

The total content of the polymerizable liquid crystal compound based on 100 parts by mass of the solid content of the composition for forming a retardation layer is usually 70 parts by mass to 99.5 parts by mass, preferably 80 parts by mass to 99 parts by mass. parts, more preferably 80 parts to 94 parts by weight, still more preferably 80 parts to 90 parts by weight. If the total content is within the above range, the resulting retardation layer tends to have high orientation. Here, the solid content refers to the total amount of components excluding the solvent from the composition.

[solvent]
The solvent is preferably a solvent that can dissolve the polymerizable liquid crystal compound, and is preferably a solvent that is inert to the polymerization reaction of the polymerizable liquid crystal compound.
Examples of solvents include alcohol solvents such as water, methanol, ethanol, ethylene glycol, isopropyl alcohol, propylene glycol, ethylene glycol methyl ether, ethylene glycol butyl ether, and propylene glycol monomethyl ether; ethyl acetate, butyl acetate, and ethylene glycol methyl ether acetate. , γ-butyrolactone, propylene glycol methyl ether acetate and ethyl lactate; ketone solvents such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, 2-heptanone and methyl isobutyl ketone; aliphatic carbonization such as pentane, hexane and heptane Hydrogen solvents; aromatic hydrocarbon solvents such as toluene and xylene; nitrile solvents such as acetonitrile; ether solvents such as tetrahydrofuran and dimethoxyethane; chlorine-containing solvents such as chloroform and chlorobenzene; dimethylacetamide, dimethylformamide, N-methyl- Examples include amide solvents such as 2-pyrrolidone and 1,3-dimethyl-2-imidazolidinone. These solvents may be used alone or in combination of two or more. Among these, alcohol solvents, ester solvents, ketone solvents, chlorine-containing solvents, amide solvents and aromatic hydrocarbon solvents are preferred.

The content of the solvent in 100 parts by weight of the composition is preferably from 50 parts by weight to 98 parts by weight, more preferably from 70 parts by weight to 95 parts by weight. Therefore, the solid content in 100 parts by mass of the composition is preferably 2 parts by mass to 50 parts by mass. When the solid content of the composition is 50 parts by mass or less, the viscosity of the composition is low, so the thickness of the retardation layer becomes substantially uniform, and there is a tendency that unevenness is less likely to occur in the retardation layer. The above-mentioned solid content can be appropriately determined in consideration of the thickness of the retardation layer to be manufactured.

<Polymerization initiator>
A polymerization initiator is a compound that generates reactive species by the contribution of heat or light and can initiate a polymerization reaction of polymerizable liquid crystals and the like. Examples of reactive species include radicals, cations, anions, and the like. Among them, from the viewpoint of easy reaction control, a photopolymerization initiator that generates radicals upon irradiation with light is preferred.
Examples of the photopolymerization initiator include benzoin compounds, benzophenone compounds, benzyl ketal compounds, α-hydroxyketone compounds, α-aminoketone compounds, triazine compounds, iodonium salts, and sulfonium salts. Specifically, Irgacure (registered trademark) 907, Irgacure 184, Irgacure 651, Irgacure 819, Irgacure 250, Irgacure 369, Irgacure 379, Irgacure 127, Irgacure 2959, Irgacure 754, Irgacure 379EG (the above, BASF Japan Ltd. (manufactured by Nippon Kayaku Co., Ltd.), Seiqual BZ, Seiqual Z, Seiqual BEE (manufactured by Seiko Kagaku Co., Ltd.), kayacure BP100 (manufactured by Nippon Kayaku Co., Ltd.), Kayacure UVI-6992 (manufactured by Dow), Adeka Optomer SP- 152, ADEKA OPTOMER SP-170, ADEKA OPTOMER N-1717, ADEKA OPTOMER N-1919, ADEKA ARCLES NCI-831, ADEKA ARCLES NCI-930 (manufactured by ADEKA Co., Ltd.), TAZ-A, TAZ -PP (manufactured by Nippon Siberhegner Co., Ltd.) and TAZ-104 (manufactured by Sanwa Chemical Co., Ltd.).
The composition for forming a retardation layer contains at least one type of photopolymerization initiator, preferably one or two types.

The photopolymerization initiator can fully utilize the energy emitted from the light source and has excellent productivity, so it is preferable that the maximum absorption wavelength is 300 nm to 400 nm, more preferably 300 nm to 380 nm. Among them, α-acetophenone type Polymerization initiators and oxime photopolymerization initiators are preferred.

As α-acetophenone compounds, 2-methyl-2-morpholino-1-(4-methylsulfanylphenyl)propan-1-one, 2-dimethylamino-1-(4-morpholinophenyl)-2-benzylbutane-1 -one and 2-dimethylamino-1-(4-morpholinophenyl)-2-(4-methylphenylmethyl)butan-1-one, and more preferably 2-methyl-2-morpholino-1-( Mention may be made of 4-methylsulfanylphenyl)propan-1-one and 2-dimethylamino-1-(4-morpholinophenyl)-2-benzylbutan-1-one. Commercially available α-acetophenone compounds include Irgacure 369, 379EG, 907 (manufactured by BASF Japan Co., Ltd.) and Seiqual BEE (manufactured by Seiko Kagaku Co., Ltd.).

Oxime-based photopolymerization initiators generate methyl radicals when irradiated with light. Due to these methyl radicals, polymerization of the polymerizable liquid crystal compound in the deep part of the retardation layer progresses suitably. Furthermore, from the viewpoint of more efficiently advancing the polymerization reaction deep in the retardation layer, it is preferable to use a photopolymerization initiator that can efficiently utilize ultraviolet rays with a wavelength of 350 nm or more. As a photopolymerization initiator that can efficiently utilize ultraviolet rays having a wavelength of 350 nm or more, triazine compounds and oxime ester type carbazole compounds are preferable, and oxime ester type carbazole compounds are more preferable from the viewpoint of sensitivity. Oxime ester type carbazole compounds include 1,2-octanedione, 1-[4-(phenylthio)-2-(O-benzoyloxime)], ethanone, 1-[9-ethyl-6-(2-methylbenzoyl) )-9H-carbazol-3-yl]-1-(O-acetyloxime) and the like. Commercial products of oxime ester type carbazole compounds include Irgacure OXE-01, Irgacure OXE-02, Irgacure OXE-03 (manufactured by BASF Japan Co., Ltd.), Adeka Optomer N-1919, Adeka Arcles NCI-831 (all of the above). , manufactured by ADEKA Co., Ltd.).

The amount of the photopolymerization initiator added is usually 0.1 parts by mass to 30 parts by mass, preferably 1 part to 20 parts by mass, and more preferably 1 part by mass, per 100 parts by mass of the polymerizable liquid crystal compound. Parts by mass to 15 parts by mass. Within the above range, the reaction of the polymerizable groups will proceed sufficiently and the orientation of the polymerizable liquid crystal compound will not be easily disturbed.

By blending a polymerization inhibitor, the polymerization reaction of the polymerizable liquid crystal compound can be controlled. Examples of polymerization inhibitors include hydroquinones having substituents such as hydroquinone and alkyl ethers; catechols having substituents such as alkyl ethers such as butylcatechol; pyrogallols, 2,2,6,6-tetramethyl-1- Examples include radical scavengers such as piperidinyloxy radical; thiophenols; β-naphthylamines and β-naphthols. In order to polymerize the polymerizable liquid crystal compound without disturbing the orientation of the polymerizable liquid crystal compound, the content of the polymerization inhibitor is usually 0.01 to 10 parts by mass based on 100 parts by mass of the polymerizable liquid crystal compound. The amount is preferably 0.1 to 5 parts by weight, more preferably 0.1 to 3 parts by weight.

Furthermore, by using a sensitizer, the sensitivity of the photopolymerization initiator can be increased. Examples of the photosensitizer include xanthone such as xanthone and thioxanthone; anthracenes having substituents such as anthracene and alkyl ether; phenothiazine; and rubrene. Examples of the photosensitizer include xanthone such as xanthone and thioxanthone; anthracenes having substituents such as anthracene and alkyl ether; phenothiazine; and rubrene. The content of the photosensitizer is usually 0.01 to 10 parts by weight, preferably 0.05 to 5 parts by weight, and more preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the polymerizable liquid crystal compound. 3 parts by mass.

[Leveling agent]
A leveling agent is an additive that has the function of adjusting the fluidity of the composition and making the film obtained by applying the composition more flat. and perfluoroalkyl leveling agents. Specifically, DC3PA, SH7PA, DC11PA, SH28PA, SH29PA, SH30PA, ST80PA, ST86PA, SH8400, SH8700, FZ2123 (all manufactured by Dow Corning Toray Co., Ltd.), KP321, KP323, KP324, KP326, K P340, KP341, 502, KBE-503, KBM-5103, KBM-602, KBM-603, KBM-903, KBE-903, KBE-9103, KBM-573, KBM-575, KBE-585, KBM-802, KBM-802, KBM-803, KBE-846, KBE-9007 (all manufactured by Shin-Etsu Chemical Co., Ltd.), TSF400, TSF401, TSF410, TSF4300, TSF4440, TSF4445, TSF-4446, TSF4452, TSF4460 (all manufactured by Momentive Performance Materials) Fluorinert (registered trademark) FC-72, fluorinert FC-40, FC-43, FC-3283 (all manufactured by Sumitomo 3M Ltd.), Megafac (registered trademark) ) R-08, R-30, R-90, F-410, F-411, F-443, F-445, F-470, F-477, F-479, F-482, F-483 (all manufactured by DIC Corporation), EFTOP (product name) EF301, EF303, EF351, EF352 (all manufactured by Mitsubishi Materials Electronic Chemicals Co., Ltd.) , Surflon (registered trademark) S-381, Surflon S-382, S-383, S-393, SC-101, SC-105, KH-40, SA-100 (all of the above are from AGC Seimi Chemical ( Co., Ltd.), product names E1830, E5844 (manufactured by Daikin Fine Chemicals Co., Ltd.), BM-1000, BM-1100, BYK-352, BYK-353 and BYK-361N (all product names: BM Chemie Co., Ltd.) (manufactured by), etc.

The content of the leveling agent in the composition for forming a retardation layer is preferably 0.01 parts by mass to 5 parts by mass, more preferably 0.05 parts by mass to 3 parts by mass, based on 100 parts by mass of the polymerizable liquid crystal compound. . It is preferable that the content of the leveling agent is within the above range because it is easy to horizontally align the polymerizable liquid crystal compound and the resulting retardation layer tends to be smoother. The composition for forming a retardation layer may contain two or more types of leveling agents.

[Base material]
Examples of the base material include a glass base material and a film base material, and a film base material is preferred from the viewpoint of processability, and a long roll-shaped film is more preferred since it can be manufactured continuously. Examples of resins constituting the film base material include polyolefins such as polyethylene, polypropylene, and norbornene polymers; cyclic olefin resins; polyvinyl alcohol; polyethylene terephthalate; polymethacrylic esters; polyacrylic esters; triacetyl cellulose, diacetyl cellulose and cellulose esters such as cellulose acetate propionate; polyethylene naphthalate; polycarbonate; polysulfone; polyether sulfone; polyether ketone; and plastics such as polyphenylene sulfide and polyphenylene oxide.
Examples of commercially available cellulose ester base materials include "FujiTac Film" (manufactured by Fuji Photo Film Co., Ltd.); "KC8UX2M", "KC8UY", and "KC4UY" (all manufactured by Konica Minolta Opto Co., Ltd.).
Commercially available cyclic olefin resins include "Topas" (registered trademark) (manufactured by Ticona (Germany)), "Aton" (registered trademark) (manufactured by JSR Corporation), "ZEONOR" (registered trademark), Examples include "ZEONEX" (registered trademark) (manufactured by Nippon Zeon Co., Ltd.) and "APEL" (registered trademark) (manufactured by Mitsui Chemicals, Inc.). Such a cyclic olefin resin can be formed into a film by a known method such as a solvent casting method or a melt extrusion method to form a base material. A commercially available cyclic olefin resin base material can also be used. Commercially available cyclic olefin resin base materials include "S-Sina" (registered trademark), "SCA40" (registered trademark) (manufactured by Sekisui Chemical Co., Ltd.), and "Zeonor Film" (registered trademark) (manufactured by Optes Co., Ltd.). ) and "Arton Film" (registered trademark) (manufactured by JSR Corporation).
As for the thickness of the base material, it is preferable that the base material has a mass that can be handled practically, but if it is too thin, the strength tends to decrease and the workability tends to be poor. The thickness of the base material is usually 5 μm to 300 μm, preferably 20 μm to 200 μm. Further, by peeling off the base material and transferring only the polymer in the oriented state of the polymerizable liquid crystal compound, a further thinning effect can be obtained.

[Alignment film]
It is preferable that an alignment film is formed on the surface of the base material to which the composition for forming a retardation layer is applied. The alignment film has an alignment regulating force to align the polymerizable liquid crystal compound in a desired direction.

As the alignment film, one that has a solvent resistance that does not dissolve when the composition for forming a retardation layer is applied, etc., and has heat resistance in heat treatment for removing the solvent and for aligning the polymerizable liquid crystal compound described below. preferable.

Such an alignment film facilitates alignment of the polymerizable liquid crystal compound. Furthermore, various orientations such as vertical orientation, horizontal orientation, hybrid orientation, and tilted orientation can be controlled depending on the type of orientation film, rubbing conditions, and light irradiation conditions.

As the alignment film forming the first retardation layer, an alignment film that exhibits alignment regulating force in the horizontal direction is used. Examples of such a horizontal alignment film include a rubbing alignment film, a photo alignment film, and a groove alignment film having an uneven pattern or a plurality of grooves on the surface. When applied to a long roll-shaped film, a photo-alignment film is preferred because the orientation direction can be easily controlled.

An oriented polymer can be used for the rubbed alignment film. Examples of oriented polymers include polyamides and gelatins having amide bonds, polyimides having imide bonds, and polyamic acid which is a hydrolyzate thereof, polyvinyl alcohol, alkyl-modified polyvinyl alcohol, polyacrylamide, polyoxazole, polyethyleneimine, and polystyrene. , polyvinylpyrrolidone, polyacrylic acid and polyacrylic esters. Two or more types of oriented polymers may be combined.

A rubbing alignment film is usually produced by coating a base material with a composition in which an alignment polymer is dissolved in a solvent (hereinafter also referred to as an alignment polymer composition), and removing the solvent to form a coating film. By rubbing, orientation regulating force can be imparted.

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

Oriented polymer compositions are commercially available. Commercially available oriented polymer compositions include Sunever (registered trademark, manufactured by Nissan Chemical Industries, Ltd.), Optomer (registered trademark, manufactured by JSR Corporation), and the like.

Examples of the method for applying the oriented polymer composition to the substrate include the same method as the method for applying the composition for forming a retardation layer to the substrate, which will be described later. Examples of methods for removing the solvent contained in the oriented polymer composition include natural drying, ventilation drying, heat drying, and reduced pressure drying.

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

A photo-alignment film is usually produced by applying a photo-alignment film-forming composition containing a polymer or monomer having a photoreactive group and a solvent to a base material, and then irradiating polarized light (preferably polarized UV) after removing the solvent. You can get it by doing that. The optical alignment film can arbitrarily control the direction of the alignment regulating force by selecting the polarization direction of the polarized light to be irradiated.

The photoreactive group refers to a group that exhibits orientation ability when irradiated with light. Specifically, groups that are involved in photoreactions that are the origin of orientation ability, such as molecular orientation-inducing reactions, isomerization reactions, photodimerization reactions, photocrosslinking reactions, or photodecomposition reactions, which are caused by light irradiation, can be mentioned. The photoreactive group is preferably a group having an unsaturated bond, especially a double bond, such as a carbon-carbon double bond (C=C bond), a carbon-nitrogen double bond (C=N bond), or a nitrogen-nitrogen double bond. Particularly preferred is a group having at least one selected from the group consisting of a double bond (N=N bond) and a carbon-oxygen double bond (C=O bond).

Examples of the photoreactive group having a C═C bond include a vinyl group, a polyene group, a stilbene group, a stilbazole group, a stilbazolium group, a chalcone group, and a cinnamoyl group. Examples of the photoreactive group having a C=N bond include groups having structures such as an aromatic Schiff base and an aromatic hydrazone. Examples of the photoreactive group having an N=N bond include an azobenzene group, an azonaphthalene group, an aromatic heterocyclic azo group, a bisazo group, a formazan group, and a group having an azoxybenzene structure. Examples of the photoreactive group having a C═O bond include a benzophenone group, a coumarin group, an anthraquinone group, and a maleimide group. These groups may have a substituent such as an alkyl group, an alkoxy group, an aryl group, an allyloxy group, a cyano group, an alkoxycarbonyl group, a hydroxyl group, a sulfonic acid group, or a halogenated alkyl group.

Groups that participate in photodimerization reactions or photocrosslinking reactions are preferred in terms of excellent orientation. Among these, photoreactive groups that participate in photodimerization reactions are preferable, and cinnamoyl groups are preferable because the amount of polarized light irradiation required for alignment is relatively small and it is easy to obtain a photoalignment film with excellent thermal stability and stability over time. and chalcone groups are preferred. As the polymer having a photoreactive group, one having a cinnamoyl group such that the end portion of the polymer side chain has a cinnamic acid structure or a cinnamic acid ester structure is particularly preferable.

The content of the polymer or monomer having a photoreactive group in the composition for forming a photo-alignment film can be adjusted depending on the type of polymer or monomer and the desired thickness of the photo-alignment film, and is at least 0.2% by mass or more. It is preferably in the range of 0.3 to 10% by mass.

Examples of the method for applying the composition for forming a photo-alignment film onto the substrate include a method similar to the method for applying the composition for forming a retardation layer to the substrate, which will be described later. The method for removing the solvent from the applied composition for forming a photo-alignment film includes the same method as the method for removing the solvent from the alignment polymer composition.

In order to irradiate polarized light, polarized light can be irradiated directly onto the composition for forming a photo-alignment film coated on a substrate, from which the solvent has been removed, or by irradiating polarized light from the substrate side. The irradiation method may be such that the irradiation is transmitted through the material. Further, it is preferable that the polarized light is substantially parallel light. The wavelength of the polarized light to be irradiated is preferably in a wavelength range in which a polymer having a photoreactive group or a photoreactive group of a monomer can absorb light energy. Specifically, UV (ultraviolet light) having a wavelength in the range of 250 nm to 400 nm is particularly preferred. Examples of light sources that emit the polarized light include xenon lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halide lamps, and ultraviolet lasers such as KrF and ArF. Among these, high-pressure mercury lamps, ultra-high-pressure mercury lamps, and metal halide lamps are preferable because they emit high ultraviolet light with a wavelength of 313 nm. Polarized UV can be irradiated by passing the light from the light source through a suitable polarizing element. Examples of the polarizing element include polarizing filters, polarizing prisms such as Glan-Thompson and Glan-Taylor, and wire grids. Among them, a wire grid type polarizing element is preferable from the viewpoint of large area and heat resistance.

Note that by performing masking when performing rubbing or polarized light irradiation, it is also possible to form a plurality of regions (patterns) in which the directions of liquid crystal alignment are different.

A groove alignment film is a film having an uneven pattern or a plurality of grooves on the film surface. When a polymerizable liquid crystal compound is applied to a film having a plurality of linear grooves arranged at equal intervals, liquid crystal molecules are aligned in the direction along the grooves.
The groove alignment film can be obtained by exposing the surface of a photosensitive polyimide film to light through an exposure mask having pattern-shaped slits, followed by development and rinsing to form a concavo-convex pattern, and by using a plate with grooves on the surface. A method in which a layer of uncured UV curable resin is formed on a shaped master, the resin layer is transferred to a base material, and then cured; Examples include a method in which a roll-shaped master disk having grooves is pressed against it to form irregularities, and then hardened.

The thickness of the alignment film for forming the first retardation layer is usually in the range of 10 to 10,000 nm, preferably in the range of 10 to 1,000 nm, and more preferably in the range of 50 to 500 nm.

As the alignment film forming the second retardation layer, an alignment film having an alignment regulating force in the vertical direction (hereinafter also referred to as a vertical alignment film) is used. As the vertical alignment film, it is preferable to use a material that lowers the surface tension of the substrate surface. Examples of such materials include the above-mentioned oriented polymers, fluorine-based polymers such as perfluoroalkyl, polyimide compounds, silane compounds, and polysiloxane compounds obtained by condensation reactions thereof. Silane compounds are preferred because they tend to reduce surface tension.

As the silane compound, silicone compounds such as the silane coupling agents mentioned above can be suitably applied, but examples include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(2-methoxyethoxy)silane, N-(2- (aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane Sidoxypropylmethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-mercapto Examples include propyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropyldimethoxymethylsilane, and 3-glycidoxypropylethoxydimethylsilane. Two or more types of silane compounds may be used.

The silane compound may be of the silicone monomer type or of the silicone oligomer (polymer) type. Examples of silicone oligomers in the form of (monomer)-(monomer) copolymers include the following.

3-mercaptopropyltrimethoxysilane-tetramethoxysilane copolymer, 3-mercaptopropyltrimethoxysilane-tetraethoxysilane copolymer, 3-mercaptopropyltriethoxysilane-tetramethoxysilane copolymer, and 3-mercaptopropyltriethoxysilane-tetraethoxy copolymers containing mercaptopropyl groups, such as silane copolymers;

Mercaptomethyl groups, such as mercaptomethyltrimethoxysilane-tetramethoxysilane copolymers, mercaptomethyltrimethoxysilane-tetraethoxysilane copolymers, mercaptomethyltriethoxysilane-tetramethoxysilane copolymers, and mercaptomethyltriethoxysilane-tetraethoxysilane copolymers. Copolymer containing;

3-methacryloyloxypropyltrimethoxysilane-tetramethoxysilane copolymer, 3-methacryloyloxypropyltrimethoxysilane-tetraethoxysilane copolymer, 3-methacryloyloxypropyltriethoxysilane-tetramethoxysilane copolymer, 3-methacryloyloxypropyltriethoxysilane -tetraethoxysilane copolymer, 3-methacryloyloxypropylmethyldimethoxysilane-tetramethoxysilane copolymer, 3-methacryloyloxypropylmethyldimethoxysilane-tetraethoxysilane copolymer, 3-methacryloyloxypropylmethyldiethoxysilane-tetramethoxysilane copolymer, and Copolymers containing methacryloyloxypropyl groups, such as 3-methacryloyloxypropylmethyldiethoxysilane-tetraethoxysilane copolymers;

3-acryloyloxypropyltrimethoxysilane-tetramethoxysilane copolymer, 3-acryloyloxypropyltrimethoxysilane-tetraethoxysilane copolymer, 3-acryloyloxypropyltriethoxysilane-tetramethoxysilane copolymer, 3-acryloyloxypropyltriethoxysilane -tetraethoxysilane copolymer, 3-acryloyloxypropylmethyldimethoxysilane-tetramethoxysilane copolymer, 3-acryloyloxypropylmethyldimethoxysilane-tetraethoxysilane copolymer, 3-acryloyloxypropylmethyldiethoxysilane-tetramethoxysilane copolymer, and Copolymers containing acryloyloxypropyl groups, such as 3-acryloyloxypropylmethyldiethoxysilane-tetraethoxysilane copolymers;

vinyltrimethoxysilane-tetramethoxysilane copolymer, vinyltrimethoxysilane-tetraethoxysilane copolymer, vinyltriethoxysilane-tetramethoxysilane copolymer, vinyltriethoxysilane-tetraethoxysilane copolymer, vinylmethyldimethoxysilane-tetramethoxysilane copolymer, Copolymers containing vinyl groups, such as vinylmethyldimethoxysilane-tetraethoxysilane copolymers, vinylmethyldiethoxysilane-tetramethoxysilane copolymers, and vinylmethyldiethoxysilane-tetraethoxysilane copolymers;

3-aminopropyltrimethoxysilane-tetramethoxysilane copolymer, 3-aminopropyltrimethoxysilane-tetraethoxysilane copolymer, 3-aminopropyltriethoxysilane-tetramethoxysilane copolymer, 3-aminopropyltriethoxysilane-tetraethoxysilane copolymer, 3-aminopropylmethyldimethoxysilane-tetramethoxysilane copolymer, 3-aminopropylmethyldimethoxysilane-tetraethoxysilane copolymer, 3-aminopropylmethyldiethoxysilane-tetramethoxysilane copolymer, and 3-aminopropylmethyldiethoxysilane copolymer. Copolymers containing amino groups, such as silane-tetraethoxysilane copolymers.

Among these, silane compounds having an alkyl group at the molecular terminal are preferred, and silane compounds having an alkyl group having 6 to 20 carbon atoms are more preferred. Since these silane compounds are liquid in most cases, they may be applied to the substrate as is, or they may be dissolved in a solvent and applied to the substrate. Moreover, it may be dissolved in a solvent and applied to a base material together with various polymers as a binder.

Examples of the method for applying the vertical alignment film to the substrate include a method similar to the method for applying the composition for forming a retardation layer to the substrate, which will be described later. The method for removing the solvent from the applied composition for forming a photo-alignment film includes the same method as the method for removing the solvent from the alignment polymer composition.

The thickness of the alignment film for forming the second retardation layer is usually in the range of 10 to 10,000 nm, preferably in the range of 50 to 5,000 nm, and more preferably in the range of 100 to 500 nm.

≪Method for manufacturing retardation layer≫
<Coating composition for forming retardation layer>
A retardation layer can be formed by applying a composition for forming a retardation layer onto the base material or alignment film. Methods for applying the retardation layer forming composition onto the base material include extrusion coating method, direct gravure coating method, reverse gravure coating method, CAP coating method, slit coating method, microgravure method, die coating method, and inkjet method. etc. Other examples include a method of coating using a coater such as a dip coater, a bar coater, or a spin coater. Among these, when coating continuously in a roll-to-roll format, microgravure, inkjet, slit coating, and die coating methods are preferred; when coating on sheet substrates such as glass, uniformity A spin coating method with a high

<Drying of composition for forming retardation layer>
Examples of the drying method for removing the solvent contained in the composition for forming a retardation layer include natural drying, ventilation drying, heat drying, reduced pressure drying, and methods combining these. Among these, natural drying or heat drying is preferred. The drying temperature is preferably in the range of 0 to 200°C, more preferably in the range of 20 to 150°C, even more preferably in the range of 50 to 130°C. The drying time is preferably 10 seconds to 20 minutes, more preferably 30 seconds to 10 minutes. The composition for forming a photoalignment film and the alignment polymer composition can also be dried in the same manner.

<Polymerization of polymerizable liquid crystal compound>
Photopolymerization is preferred as a method for polymerizing the polymerizable liquid crystal compound. Photopolymerization is carried out by irradiating active energy rays to a laminate in which a composition for forming a retardation layer containing a polymerizable liquid crystal compound is coated on a substrate or an alignment film. The active energy rays to be irradiated include the type of polymerizable liquid crystal compound contained in the dry film (especially the type of photopolymerizable functional group that the polymerizable liquid crystal compound has), and the photopolymerization initiator if it contains a photopolymerization initiator. are appropriately selected depending on the types and amounts thereof. Specifically, one or more types of light selected from the group consisting of visible light, ultraviolet light, infrared light, X-rays, α-rays, β-rays, and γ-rays can be mentioned. Among these, ultraviolet light is preferable because it is easy to control the progress of the polymerization reaction and it is possible to use photopolymerization equipment that is widely used in the field. It is preferable to select the type of liquid crystal compound.

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

The ultraviolet irradiation intensity is usually 10 mW/cm ² to 3,000 mW/cm ² . The ultraviolet irradiation intensity is preferably an intensity in a wavelength range effective for activating a cationic polymerization initiator or a radical polymerization initiator. The time for irradiating the light is usually 0.1 seconds to 10 minutes, preferably 0.1 seconds to 5 minutes, more preferably 0.1 seconds to 3 minutes, and even more preferably 0.1 seconds. ~1 minute. When irradiated once or multiple times with such ultraviolet irradiation intensity, the cumulative amount of light is 10 mJ/cm ² to 3,000 mJ/cm ² , preferably 50 mJ/cm ² to 2,000 mJ/cm ² , more preferably 100 mJ /cm ² to 1,000 mJ/cm ² . If the cumulative amount of light is below this range, the polymerizable liquid crystal compound may not be sufficiently cured, and good transferability may not be obtained. On the other hand, if the cumulative amount of light is above this range, the optical film including the retardation layer may be colored.

[Polarizer]
The elliptically polarizing plate of the present invention includes a polarizing plate and the optical film of the present invention, and for example, the polarizing plate and the optical film of the present invention are bonded together via an adhesive or an adhesive layer. In this way, the elliptically polarizing plate of the present invention can be obtained.
In one embodiment of the present invention, when a polarizing plate and the optical film of the present invention are laminated, the slow axis (optical axis) of the first retardation layer and the absorption axis of the polarizing plate are set at substantially 45°. It is preferable to laminate them so that By laminating the slow axis (optical axis) of the optical film of the present invention and the absorption axis of the polarizing plate so that the angle is substantially 45°, the function as a circularly polarizing plate can be obtained. Note that substantially 45° is usually in the range of 45±5°.

The polarizing plate is made of a polarizer having a polarizing function. Examples of the polarizer include a stretched film on which a dye with absorption anisotropy is adsorbed, or a film on which a dye with absorption anisotropy is coated and oriented. Examples of dyes having absorption anisotropy include dichroic dyes.

Stretched films that have adsorbed dyes with absorption anisotropy are usually produced by uniaxially stretching a polyvinyl alcohol resin film or by dyeing the polyvinyl alcohol resin film with a dichroic dye. It is manufactured through the following steps: adsorption, treatment of the polyvinyl alcohol resin film on which the dichroic dye has been adsorbed with a boric acid aqueous solution, and washing with water after the treatment with the boric acid aqueous solution. A polarizing plate is obtained by bonding the polarizer thus obtained and a transparent protective film. Examples of dichroic dyes include iodine and dichroic organic dyes. Examples of dichroic organic dyes include dichroic direct dyes made of disazo compounds such as CI DIRECT RED 39, and dichroic direct dyes made of compounds such as trisazo and tetrakisazo. As described above, the thickness of the polarizer obtained by subjecting a polyvinyl alcohol resin film to uniaxial stretching, dyeing with a dichroic dye, boric acid treatment, washing with water, and drying is preferably 5 μm to 40 μm.

[Adhesive]
Examples of the adhesive for bonding the polarizing plate and the optical film of the present invention or the optical film of the present invention and a display device include pressure-sensitive adhesives, dry-setting adhesives, and chemically reactive adhesives. Examples of chemically reactive adhesives include active energy ray-curable adhesives. The adhesive between the polarizing plate and the optical film of the present invention is preferably an adhesive layer formed from a pressure-sensitive adhesive, a dry-setting adhesive, or an active energy ray-curable adhesive. As the adhesive between the optical film and the display device, a pressure-sensitive adhesive or an active energy ray-curable adhesive is preferable.

Pressure-sensitive adhesives typically contain a polymer and may also contain a solvent.
Examples of the polymer include acrylic polymers, silicone polymers, polyesters, polyurethanes, and polyethers. Among these, acrylic adhesives containing acrylic polymers have excellent optical transparency, moderate wettability and cohesive strength, excellent adhesive properties, and are also highly weather resistant and heat resistant, and can be heated easily. This is preferable because it is unlikely to cause lifting or peeling under humid conditions.

Acrylic polymers include (meth)acrylates (hereinafter, acrylates and methacrylates are collectively referred to as (meth)acrylates) in which the alkyl group in the ester moiety is an alkyl group having 1 to 20 carbon atoms such as a methyl group, ethyl group, or butyl group. (acrylic acid and methacrylic acid are sometimes collectively referred to as (meth)acrylic acid), and (meth)acrylic acid with a functional group such as (meth)acrylic acid or hydroxyethyl (meth)acrylate. Copolymers with acrylic monomers are preferred.

Pressure-sensitive adhesives containing such copolymers have excellent adhesive properties, and can be removed relatively easily after being attached to a display device without leaving any adhesive residue on the display device. This is preferable because it is possible. The glass transition temperature of the acrylic polymer is preferably 25°C or lower, more preferably 0°C or lower. The mass average molecular weight of such an acrylic polymer is preferably 100,000 or more.

Examples of the solvent include the solvents listed above. The pressure sensitive adhesive may contain a light diffusing agent. The light diffusing agent is an additive that imparts light diffusing properties to the adhesive, and may be fine particles having a refractive index different from the refractive index of the polymer contained in the adhesive. Examples of the light diffusing agent include fine particles made of an inorganic compound and fine particles made of an organic compound (polymer). Many of the polymers contained as active ingredients in adhesives, including acrylic polymers, have a refractive index of about 1.4 to 1.6, so light diffusing agents with a refractive index of 1.2 to 1.8 It is preferable to select it appropriately. The refractive index difference between the polymer contained as an active ingredient in the adhesive and the light diffusing agent is usually 0.01 or more, and preferably 0.01 to 0.2 from the viewpoint of brightness and display performance of the display device. The fine particles used as the light diffusing agent are preferably spherical fine particles, particularly nearly monodisperse fine particles, and more preferably fine particles having an average particle size of 2 μm to 6 μm. The refractive index is measured by the common minimum deviation method or Abbe refractometer.
Examples of fine particles made of inorganic compounds include aluminum oxide (refractive index 1.76) and silicon oxide (refractive index 1.45). Fine particles made of organic compounds (polymers) include melamine beads (refractive index 1.57), polymethyl methacrylate beads (refractive index 1.49), and methyl methacrylate/styrene copolymer resin beads (refractive index 1.50). ~1.59), polycarbonate beads (refractive index 1.55), polyethylene beads (refractive index 1.53), polystyrene beads (refractive index 1.6), polyvinyl chloride beads (refractive index 1.46), and silicone Examples include resin beads (refractive index 1.46). The content of the light diffusing agent is usually 3 parts by mass to 30 parts by mass based on 100 parts by mass of the polymer.
The thickness of the pressure-sensitive adhesive is determined depending on its adhesion strength, etc., and is not particularly limited, but is usually 1 μm to 40 μm. In terms of processability, durability, etc., the thickness is preferably 3 μm to 25 μm, more preferably 5 μm to 20 μm. By setting the thickness of the adhesive layer formed from the adhesive to 5 μm to 20 μm, it maintains brightness when the display device is viewed from the front or from an angle, and prevents blurring and blurring of the displayed image. It can be made less likely to occur.

[Drying and solidifying adhesive]
The dry-setting adhesive may contain a solvent.
The dry-setting adhesive contains as a main component a polymer of a monomer having a protic functional group such as a hydroxyl group, a carboxyl group, or an amino group and an ethylenically unsaturated group, or a urethane resin, and further contains a polyvalent Examples include compositions containing crosslinking agents or curable compounds such as aldehydes, epoxy compounds, epoxy resins, melamine compounds, zirconia compounds, and zinc compounds. Examples of polymers of monomers having protic functional groups such as hydroxyl groups, carboxyl groups, or amino groups and ethylenically unsaturated groups include ethylene-maleic acid copolymers, itaconic acid copolymers, acrylic acid copolymers, and acrylamide. Examples include copolymers, saponified polyvinyl acetate, and polyvinyl alcohol resins.

Examples of polyvinyl alcohol resins include polyvinyl alcohol, partially saponified polyvinyl alcohol, completely saponified polyvinyl alcohol, carboxyl group-modified polyvinyl alcohol, acetoacetyl group-modified polyvinyl alcohol, methylol group-modified polyvinyl alcohol, and amino group-modified polyvinyl alcohol. Can be mentioned. The content of polyvinyl alcohol resin in the water-based adhesive is usually 1 part by mass to 10 parts by mass, preferably 1 part by mass to 5 parts by mass, per 100 parts by mass of water.

Examples of the urethane resin include polyester-based ionomer type urethane resins. The polyester-based ionomer type urethane resin referred to herein is a urethane resin having a polyester skeleton into which a small amount of an ionic component (hydrophilic component) is introduced. Such an ionomer-type urethane resin emulsifies in water to form an emulsion without using an emulsifier, and therefore can be used as a water-based adhesive. When using a polyester ionomer type urethane resin, it is effective to blend a water-soluble epoxy compound as a crosslinking agent.

Examples of the epoxy resin include polyamide epoxy resins obtained by reacting epichlorohydrin with a polyamide polyamine obtained by reacting a polyalkylene polyamine such as diethylene triamine or triethylene tetramine with a dicarboxylic acid such as adipic acid. Commercially available polyamide epoxy resins include "SUMIREZ RESIN (registered trademark) 650" and "SUMIRAZE RESIN 675" (manufactured by Sumika Chemtex Co., Ltd.), and "WS-525" (manufactured by Nippon PMC Corporation). etc. When blending an epoxy resin, the amount added is usually 1 part by mass to 100 parts by mass, preferably 1 part by mass to 50 parts by mass, per 100 parts by mass of polyvinyl alcohol resin.

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

[Active energy ray curable adhesive]
The active energy ray curable adhesive may contain a solvent. An active energy ray-curable adhesive is an adhesive that hardens upon irradiation with active energy rays.
Active energy ray-curable adhesives include cationically polymerizable adhesives containing an epoxy compound and a cationic polymerization initiator, radically polymerizable adhesives containing an acrylic curing component and a radical polymerization initiator, and epoxy compounds. An adhesive containing both a cationically polymerizable curing component such as cationic polymerizable curing component and a radically polymerizable curing component such as acrylic compound, and further contains a cationic polymerization initiator and a radical polymerization initiator, and an adhesive containing these polymerization initiators. Examples include adhesives that are cured by irradiation with an electron beam.

Among them, radically polymerizable active energy ray-curable adhesives containing an acrylic curing component and a radical polymerization initiator, and cationically polymerizable active energy ray-curable adhesives containing an epoxy compound and a cationic polymerization initiator are used. preferable. Examples of the acrylic curing component include (meth)acrylates such as methyl (meth)acrylate and hydroxyethyl (meth)acrylate, and (meth)acrylic acid. The active energy ray-curable adhesive containing an epoxy compound may further contain a compound other than the epoxy compound. Examples of compounds other than epoxy compounds include oxetane compounds and acrylic compounds.
Examples of the radical polymerization initiator include the photopolymerization initiators described above. Commercially available cationic polymerization initiators include the "Kayarad" (registered trademark) series (manufactured by Nippon Kayaku Co., Ltd.), the "Cylacure UVI" series (manufactured by Dow Chemical Co., Ltd.), the "CPI" series (manufactured by Sun-Apro Co., Ltd.), Examples include “TAZ”, “BBI” and “DTS” (manufactured by Midori Kagaku Co., Ltd.), “ADEKA Optomer” series (manufactured by ADEKA Co., Ltd.), “RHODORSIL” (registered trademark) (manufactured by Rhodia Co., Ltd.), etc. It will be done. The content of the radical polymerization initiator and the cationic polymerization initiator is usually 0.5 parts by mass to 20 parts by mass, preferably 1 part by mass to 15 parts by mass, based on 100 parts by mass of the active energy ray-curable adhesive. Department.

Active energy ray-curable adhesives further contain ion trapping agents, antioxidants, chain transfer agents, tackifiers, thermoplastic resins, fillers, flow regulators, plasticizers, antifoaming agents, etc. It's okay.

In this specification, an active energy ray is defined as an energy ray that can decompose a compound that generates active species to generate active species. Examples of such active energy rays include visible light, ultraviolet rays, infrared rays, X-rays, α rays, β rays, γ rays, and electron rays, with ultraviolet rays and electron rays being preferred. Preferred ultraviolet irradiation conditions are the same as those for polymerization of the polymerizable liquid crystal compound described above.

[Display device]
The present invention can provide a display device including the optical film of the present invention as one of the embodiments. Further, the display device may include the elliptically polarizing plate according to the embodiment.
The display device is a device having a display mechanism, and includes a light emitting element or a light emitting device as a light source. Display devices include liquid crystal display devices, organic electroluminescent (EL) display devices, inorganic electroluminescent (EL) display devices, touch panel display devices, electron emission display devices (field emission display devices (FEDs, etc.), surface field emission display devices) (SED)), electronic paper (display device using electronic ink or electrophoretic element), plasma display device, projection type display device (grating light valve (GLV) display device, display device with digital micromirror device (DMD)) etc.) and piezoelectric ceramic displays. The liquid crystal display device includes any of a transmissive liquid crystal display device, a transflective liquid crystal display device, a reflective liquid crystal display device, a direct view type liquid crystal display device, a projection type liquid crystal display device, and the like. These display devices may be display devices that display two-dimensional images or stereoscopic display devices that display three-dimensional images. In particular, as a display device including an optical film and a polarizing plate according to the present invention, an organic EL display device and a touch panel display device are preferable.

Hereinafter, the present invention will be explained in more detail with reference to Examples. In addition, "%" and "parts" in the examples mean % by mass and parts by mass unless otherwise specified. Furthermore, the polymer films, devices, and measuring methods used in the following examples are as follows.

- ZF-14 manufactured by Nippon Zeon Co., Ltd. was used as the cycloolefin polymer (COP) film.
- AGF-B10 manufactured by Kasuga Denki Co., Ltd. was used as the corona treatment device.
- Corona treatment was performed once using the above-mentioned corona treatment apparatus under conditions of an output of 0.3 kW and a treatment speed of 3 m/min.
- SPOT CURE SP-9 with a polarizer unit manufactured by Ushio Inc. was used as the polarized UV irradiation device.
- For the high-pressure mercury lamp, Unicure VB-15201BY-A manufactured by Ushio Inc. was used.
- The phase difference value Re (λ) in the in-plane direction was measured using KOBRA-WPR manufactured by Oji Scientific Instruments Co., Ltd.
- The retardation value Rth (λ) in the thickness direction and the film thickness were measured using an ellipsometer M-220 manufactured by JASCO Corporation.

[Preparation of alignment film composition for forming first retardation layer]
5 parts of a photo-alignable material having the following structure (weight average molecular weight: 30,000) and 95 parts of cyclopentanone (solvent) were mixed as components, and the resulting mixture was stirred at 80°C for 1 hour to obtain the first. An alignment film composition for forming a retardation layer was obtained.

[Preparation of alignment film composition for forming second retardation layer]
Silane coupling agent KBE-9103 manufactured by Shin-Etsu Chemical Co., Ltd. was dissolved in a mixed solvent of ethanol and water at a ratio of 9:1 (weight ratio) to form a second retardation layer with a solid content of 1%. An alignment film composition was obtained.

[Preparation of first and second compositions for forming retardation layers (compositions I to IV)]
To a mixture of polymerizable liquid crystal compound A and polymerizable liquid crystal compound B described below, 0.1 part of a leveling agent (F-556; manufactured by DIC Corporation) and a polymerization initiator 2-dimethylamino-2- 6 parts of benzyl-1-(4-morpholinophenyl)butan-1-one (Irgacure 369 (Irg369); manufactured by BASF Japan Ltd.) was added.
Furthermore, N-methyl-2-pyrrolidone (NMP) was added as a solvent so that the solid content concentration was 13%, and the mixture was stirred at 80°C for 1 hour to form the first and second retardation layers. A composition was obtained. The mixture ratio of polymerizable liquid crystal compound A and polymerizable liquid crystal compound B was added as shown in Table 1 according to the desired wavelength dispersion value α, and the names of the respective compositions are shown in Table 1. As stated.

※重合性液晶化合物Ａ、及びＢの比率は、重合性液晶化合物総量に対する比率とする。

*The ratio of polymerizable liquid crystal compounds A and B is the ratio to the total amount of polymerizable liquid crystal compounds.

Polymerizable liquid crystal compound A was produced by the method described in JP-A-2010-31223. Furthermore, polymerizable liquid crystal compound B was produced according to the method described in JP-A No. 2009-173893. The molecular structure of each is shown below.

Polymerizable liquid crystal compound A

Polymerizable liquid crystal compound B

[Preparation of liquid crystal composition for forming first and second retardation layers (composition V)]
To the liquid crystal compound LC242 described below: Paliocolor LC242 (registered trademark of BASF), 0.1 part of leveling agent F-556 and 3 parts of polymerization initiator Irg369 were added so that the solid content concentration was 13%. cyclopentanone was added to obtain liquid crystal compositions for forming first and second retardation layers. The name of the obtained liquid crystal composition is "Composition V".
Liquid crystal compound LC242: Paliocolor LC242 (registered trademark of BASF)

(Example 1)
[Manufacture of first retardation layer]
The alignment film composition for forming the first retardation layer was coated on a COP film (ZF-14-50) manufactured by Zeon Corporation using a bar coater, dried at 80°C for 1 minute, and coated with a polarized UV irradiation device ( Using SPOT CURE SP-9 (manufactured by Ushio Inc.), polarized UV exposure was carried out at an axis angle of 45° and an integrated light amount of 100 mJ/cm ² at a wavelength of 313 nm. The film thickness of the obtained first alignment film for forming a retardation layer was measured with an ellipsometer and was found to be 100 nm.
Subsequently, Composition I was applied to the first alignment film for forming a retardation layer using a bar coater, and after drying at 120°C for 1 minute, a high-pressure mercury lamp (Unicure VB-15201BY-A, Ushio Inc. A first retardation layer is formed by irradiating ultraviolet rays from the side coated with the composition of the retardation layer (in a nitrogen atmosphere, cumulative amount of light at a wavelength of 365 nm: 500 mJ/cm ² ) using did. The thickness of the obtained first alignment film for forming a retardation layer was measured with an ellipsometer and was found to be 2.3 μm.

[Manufacture of second retardation layer]
The alignment film composition for forming the second retardation layer was coated on a COP film (ZF-14-50) manufactured by Zeon Corporation using a bar coater, dried at 120°C for 1 minute, and then the second retardation layer was formed. An alignment film for layer formation was obtained. The thickness of the obtained second alignment film for forming a retardation layer was measured with an ellipsometer and was found to be 200 nm.
Subsequently, Composition I was applied to the alignment film for forming the second retardation layer using a bar coater, dried at 120°C for 1 minute, and then heated using a high-pressure mercury lamp (Unicure VB-15201BY-A, Ushio Inc.). A second retardation layer is formed by irradiating ultraviolet rays (integrated light amount at a wavelength of 365 nm in a nitrogen atmosphere: 500 mJ/cm ² ) from the side coated with the composition of the retardation layer using a retardation layer (manufactured by the company). did. The thickness of the obtained second alignment film for forming a retardation layer was measured with an ellipsometer and was found to be 1.2 μm.

[Re measurement of first retardation layer and second retardation layer]
The in-plane retardation values (Re1 (λ) and Re2 (λ)) of the first retardation layer and the second retardation layer produced by the above method indicate that the cycloolefin polymer film that is the base material has a retardation. After confirming that there were no particles, measurements were made using a measuring device (KOBRA-WR, manufactured by Oji Scientific Instruments) at wavelengths λ of 450 nm, 550 nm, and 650 nm, respectively. The results obtained are shown in Table 2.

[Rth measurement of first retardation layer and second retardation layer]
The retardation values in the thickness direction (Rth1 (λ) and Rth2 (λ)) of the first retardation layer and the second retardation layer manufactured by the above method indicate that the cycloolefin polymer film as the base material has a retardation. After confirming that there was no such phenomenon, measurements were taken using an ellipsometer while changing the angle of incidence of light onto the sample. Further, the average refractive index at wavelengths λ of 450 nm and 550 nm was measured using a refractometer (“Multi-wavelength Abbe refractometer DR-M4” manufactured by Atago Co., Ltd.). Table 2 shows the obtained film thickness, average refractive index, and Rth1 (λ) and Rth2 (λ) at wavelengths λ of 450 nm and 550 nm calculated from the measurement results of the ellipsometer.

[Calculation of Nz(λ)]
Nz(λ) of the optical film in which the first retardation layer and the second retardation layer were laminated was calculated according to formula (C). The calculated results are shown in Table 2.

Note that the refractive indexes nx1(λ), ny1(λ), and nz1(λ) of the obtained first retardation layer satisfy nx1(λ)>ny1(λ)≈nz1 in the entire wavelength range λ=400 to 700 nm. (λ) is satisfied. Furthermore, the refractive indexes nx2(λ), ny2(λ), and nz2(λ) of the second retardation layer are nz2(λ)>nx2(λ)≈ny2(λ) in the entire wavelength range λ=400 to 700 nm. satisfy.

[Manufacture of polarizing plate]
After immersing a 75 μm thick polyvinyl alcohol film with an average degree of polymerization of about 2,400 and a saponification degree of 99.9 mol% or more in pure water at 30°C, the weight ratio of iodine/potassium iodide/water was 0. Iodine staining was carried out by immersing it in an aqueous solution of 02/2/100 at 30°C (iodine staining process). The polyvinyl alcohol film that had undergone the iodine dyeing process was treated with boric acid by immersing it at 56.5°C in an aqueous solution with a weight ratio of potassium iodide/boric acid/water of 12/5/100 (boric acid treatment process). ). After washing the polyvinyl alcohol film that had undergone the boric acid treatment process with pure water at 8°C, it was dried at 65°C to obtain a polarizer (thickness 27 μm after stretching) in which iodine was adsorbed and oriented in polyvinyl alcohol. . At this time, stretching was performed in the iodine dyeing step and the boric acid treatment step. The total stretching ratio in this stretching was 5.3 times. The obtained polarizer and a saponified triacetyl cellulose film (KC4UYTAC 40 μm, manufactured by Konica Minolta) were bonded together using a nip roll via a water-based adhesive. While maintaining the tension of the obtained bond at 430 N/m, it was dried at 60° C. for 2 minutes to obtain a polarizing plate having a triacetyl cellulose film as a protective film on one side. The water-based adhesive is 100 parts of water, 3 parts of carboxyl-modified polyvinyl alcohol (Kuraray Poval KL318, manufactured by Kuraray), and a water-soluble polyamide epoxy resin (Sumiraze Resin 650, manufactured by Sumika Chemtex, an aqueous solution with a solid content concentration of 30%). It was prepared by adding 1.5 parts.

The optical properties of the obtained polarizing plate were measured. The measurement was carried out using a spectrophotometer (V7100, manufactured by JASCO) using the polarizer surface of the polarizing plate obtained above as the incident plane. The obtained visibility-corrected single transmittance was 42.1%, the visibility-corrected polarization degree was 99.996%, the single hue a was -1.1, and the single hue b was 3.7.

[Manufacture of elliptically polarizing plate]
First, corona treatment was performed on the surface coated with the polymerizable liquid crystal compound of the first retardation layer, and then an adhesive (pressure-sensitive adhesive manufactured by Lintec Corporation, 5 μm) was applied to the polarizing plate manufactured by the method described above. ), the base material was peeled off to form a laminate of the polarizing plate and the first retardation layer. Subsequently, after performing corona treatment on the surface coated with the polymerizable liquid crystal compound of the second retardation layer, the polarizing plate and the first retardation layer are bonded to each other via an adhesive (pressure-sensitive adhesive manufactured by Lintec Corporation, 5 μm). The first retardation layer and the second retardation layer of the layer laminate were bonded together. Thereafter, the base material was peeled off to produce an elliptically polarizing plate.

[Check frontal hue and oblique hue change]
The obtained elliptically polarizing plate was attached to a mirror via an adhesive, and then visually observed from a distance of 50 cm from the front to confirm the hue. Further, the oblique hue was confirmed by visual observation at a distance of 50 cm from an elevation angle of 60° and an azimuth angle of 0 to 360°. The confirmed results are shown in Table 2.
Note that the frontal hue and oblique hue are as follows.
◎: Clear black, 〇: Black, △: Red or bluish black, ×: Red or blue

(Examples 2 to 30, Comparative Examples 1 to 12)
An optical film and an elliptically polarizing plate were produced in the same manner as in Example 1, except that Composition I was changed to Composition II, Composition III, Composition IV, or Composition V, respectively, according to the description in Table 2. Table 2 shows the results of each measurement.
Note that the refractive indexes nx1(λ), ny1(λ), and nz1(λ) of the first retardation layers obtained in Examples 2 to 30 are nx1(λ) over the entire wavelength range of 400 to 700 nm. )>ny1(λ)≒nz1(λ). Furthermore, the refractive indexes nx2(λ), ny2(λ), and nz2(λ) of the second retardation layer are nz2(λ)>nx2(λ)≈ny2(λ) in the entire wavelength range λ=400 to 700 nm. satisfy.

(Example 31)
Composition I was changed according to the description in Table 2, and the stacking order of the first retardation layer and the second retardation layer in the method for manufacturing an elliptically polarizing plate was changed so that the polarizing plate and the second retardation layer were stacked first. An optical film and an elliptically polarizing plate were produced in the same manner as in Example 1, except that after lamination, the order was changed to laminate the laminate of the polarizing plate, the second retardation layer, and the first retardation layer. The measurement results are shown in Table 2.
Note that the refractive indices nx1(λ), ny1(λ), and nz1(λ) of the first retardation layer obtained in Example 31 satisfy nx1(λ)>ny1( λ)≒nz1(λ). Furthermore, the refractive indexes nx2(λ), ny2(λ), and nz2(λ) of the second retardation layer are nz2(λ)>nx2(λ)≈ny2(λ) in the entire wavelength range λ=400 to 700 nm. satisfy.

The elliptically polarizing plate having the first retardation layer and the second retardation layer described in the examples has a black front hue and an oblique hue, and has excellent antireflection properties.

Claims (14)

An optical film having two retardation layers, the two retardation layers being a first retardation layer and a second retardation layer , satisfying the relationships of the following formulas (1) and (2),
0.4≦Nz(450)≦0.6 (1)
0.4≦Nz(550)≦0.6 (2)
[In the formula, Nz (450) represents the Nz coefficient of the optical film for light with wavelength λ = 450 nm, Nz (550) represents the Nz coefficient of the optical film for light with wavelength λ = 550 nm, and The Nz coefficient Nz (λ) of the optical film for light is Nz (λ) = (nx (λ) - nz (λ)) / (nx (λ) - ny (λ))
It is shown by. nx (λ) represents the principal refractive index in a direction parallel to the film plane for light with a wavelength λ (nm) in the refractive index ellipsoid formed by the optical film. ny (λ) is the refraction of light of wavelength λ (nm) in a direction parallel to the film plane and orthogonal to the direction of nx (λ) in the index ellipsoid formed by the optical film. represents the rate. nz (λ) represents the refractive index in the direction perpendicular to the film plane for light with a wavelength λ (nm) in the refractive index ellipsoid formed by the optical film. ]
The first retardation layer is a film consisting of a coating layer formed by polymerizing polymerizable liquid crystal in an oriented state,
The polymerizable liquid crystal is a thermotropic liquid crystal,
The first retardation layer has a wavelength λ in the range of 400 to 700 nm in the index ellipsoid formed by the first retardation layer,
nx1(λ)>ny1(λ)≒nz1(λ)
[In the formula, nx1 (λ) represents the principal refractive index in the direction parallel to the film plane for light of wavelength λ (nm) in the refractive index ellipsoid formed by the first retardation layer. ny1 (λ) is a wavelength λ (nm) in a direction parallel to the film plane and orthogonal to the direction of nx1 (λ) in the refractive index ellipsoid formed by the first retardation layer. represents the refractive index for light. nz1 (λ) represents the refractive index in the direction perpendicular to the film plane for light of wavelength λ (nm) in the refractive index ellipsoid formed by the first retardation layer. ]
have the relationship of
An optical film that satisfies the relationships of formulas (3) and (4) below.
0.82≦Re1(450)/Re1(550)≦1.00 (3)
1.00≦Re1(650)/Re1(550) (4)
[In the formula, Re1 (450) is the in-plane retardation value of the first retardation layer for light with a wavelength λ = 450 nm, and Re1 (550) is the in-plane retardation value of the first retardation layer for light with a wavelength λ = 550 nm. Re1 (650) indicates the in-plane retardation value of the first retardation layer for light with a wavelength λ = 650 nm, and Re1 (650) indicates the in-plane retardation value of the first retardation layer for light with a wavelength λ nm. The value Re1(λ) is
Re1(λ)=(nx1(λ)−ny1(λ))×d1
It is expressed as Here, d1 represents the thickness of the first retardation layer. ] The second retardation layer is
In the range of wavelength λ = 400 to 700 nm in the refractive index ellipsoid formed by the second retardation layer,
nz2(λ)>nx2(λ)≒ny2(λ)
[In the formula, nz2 (λ) represents the refractive index in the direction perpendicular to the film plane for light with a wavelength λ (nm) in the refractive index ellipsoid formed by the second retardation layer. nx2(λ) represents the principal refractive index in the direction parallel to the film plane for light of wavelength λ (nm) in the refractive index ellipsoid formed by the second retardation layer. ny2 (λ) is the refractive index ellipsoid formed by the second retardation layer, which is parallel to the film plane and perpendicular to the direction of nx2 for light of wavelength λ (nm). Represents refractive index. However, when nx2(λ)=ny2(λ), nx2(λ) represents the refractive index in any direction parallel to the film plane. ]
have the relationship of
The optical film according to claim 1, which satisfies the following formulas (5) and (6).
Rth2(450)/Rth2(550)≦1.00 (5)
1.00≦Rth2(650)/Rth2(550) (6)
[In the formula, Rth2 (450) is the retardation value in the thickness direction of the second retardation layer for light with a wavelength λ = 450 nm, and Rth2 (550) is the retardation value of the second retardation layer for light with a wavelength λ = 550 nm. Rth2 (650) represents the retardation value in the thickness direction of the second retardation layer for light with a wavelength of 650 nm, and Rth2 (650) represents the retardation value of the second retardation layer in the thickness direction for light with a wavelength of λ (nm). The retardation value Rth2(λ) in the thickness direction is
Rth2(λ)=[(nx2(λ)+ny2(λ))/2-nz2(λ)]×d2
It is expressed as Here, in the refractive index ellipsoid formed by the second retardation layer, nz2 (λ) represents the principal refractive index in the direction perpendicular to the film plane at the wavelength λ (nm), and ((nx2 (λ) + ny2 (λ))/2) represents the average refractive index at the film plane at wavelength λ (nm). d2 represents the thickness of the second retardation layer. ] The optical film according to claim 1 or 2, wherein the first retardation layer further satisfies the following formula (7).
120nm≦Re1(550)≦170nm (7)
[In the formula, Re1 (550) represents the in-plane retardation value of the first retardation layer for light with a wavelength λ=550 nm. ] The optical film according to any one of claims 1 to 3, wherein the second retardation layer further has optical properties represented by formula (8).
-100nm≦Rth2(550)≦-50nm (8)
[In the formula, Rth2 (550) represents the retardation value in the thickness direction of the second retardation layer with respect to light with a wavelength λ=550 nm. ] 5. The optical film according to claim 1, wherein the second retardation layer is a film comprising a coating layer formed by polymerizing polymerizable liquid crystal in an oriented state. The optical film according to any one of claims 1 to 5, wherein the second retardation layer has a thickness of 5 μm or less. The optical film according to any one of claims 1 to 6, wherein the first retardation layer has a thickness of 5 μm or less. 8. The optical film according to claim 1, wherein the first retardation layer and the second retardation layer are coating layers formed by polymerizing the same polymerizable liquid crystal compound. An elliptically polarizing plate with an optical compensation function, comprising the optical film according to any one of claims 1 to 8 and a polarizing plate. The absorption axis of the polarizing plate and the slow axis of the first retardation layer have a relationship of 45±5° or 135±5° in the film plane, and the absorption axis of the polarizing plate and the slow axis of the first retardation layer The elliptically polarizing plate with an optical compensation function according to claim 9, wherein the slow axis of the second retardation layer and the slow axis of the second retardation layer are perpendicular to the film surface in a direction perpendicular to the film surface. The ellipse with an optical compensation function according to claim 9 or 10, which is an optical laminate in which a polarizing plate, an adhesive layer, a first retardation layer, an adhesive layer, and a second retardation layer are formed in this order. Polarizer. The ellipse with an optical compensation function according to claim 9 or 10, which is an optical laminate in which a polarizing plate, an adhesive layer, a second retardation layer, an adhesive layer, and a first retardation layer are formed in this order. Polarizer. An organic EL display device comprising the elliptically polarizing plate with optical compensation function according to any one of claims 9 to 12. The method for producing an elliptically polarizing plate with optical compensation function according to any one of claims 9 to 12, comprising all of the following steps.
(Step 1-A) A step of forming a first retardation layer by coating a polymerizable liquid crystal compound on the base material on which the horizontal alignment film is formed and then polymerizing it in a horizontally aligned state;
(Step 1-B) A step of forming a second retardation layer by coating a polymerizable liquid crystal compound on the base material on which the vertical alignment film is formed and then polymerizing it in a vertically aligned state;
(Step 2) Step of transferring the liquid crystal polymer of the first retardation layer and the liquid crystal polymer of the second retardation layer from the base material through an adhesive and laminating them on the polarizing plate.