JP2018136483A - Optical film and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a novel optical film that is subjected to three-dimensional photorefractive control with respect to the whole visible light region and all visual azimuths, and a method of producing the same.SOLUTION: An optical film has a first retardation layer and a second retardation layer, satisfying the relationships of the following formulae (1) and (2): 0.4≤Nz(450)≤0.6 (1) and 0.4≤Nz(550)≤0.6 (2) [where, Nz(450) indicates an Nz coefficient of the optical film with respect to light of wavelength λ=450 nm, and Nz(550) indicates an Nz coefficient of the optical film with respect to light of wavelength λ=550 nm].SELECTED DRAWING: None

Description

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

  Optical films such as polarizing plates and retardation plates are used in flat panel display devices (FPD). The phase difference plate is required to have uniform phase conversion over the entire visible light region. For example, Patent Document 1 discloses a reverse wavelength dispersive retardation film oriented in the horizontal direction, and Patent Document 2 oriented in the vertical direction. A reverse wavelength dispersive retardation film is disclosed.

Special table 2010-537955 gazette Japanese Patent Laying-Open No. 2015-57646

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

  The present invention includes the following inventions.

[1] An optical film having a first retardation layer and a second retardation layer and satisfying the relationship 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 of wavelength λ = 450 nm, Nz (550) represents the Nz coefficient of the optical film for light of wavelength λ = 550 nm, and The Nz coefficient Nz (λ) of the optical film with respect to light is Nz (λ) = (nx (λ) −nz (λ)) / (nx (λ) −ny (λ))
Indicated by. In the refractive index ellipsoid formed by the optical film, nx (λ) represents a main refractive index in a direction parallel to the film plane with respect to light having a wavelength λ (nm). ny (λ) is a refractive index in the refractive index ellipsoid formed by the optical film, parallel to the plane of the film with respect to light of wavelength λ (nm) and perpendicular to the direction of nx (λ). Represents a rate. In the refractive index ellipsoid formed by the optical film, nz (λ) represents a refractive index in a direction perpendicular to the film plane with respect to light having a wavelength λ (nm). ]

[2] The first retardation layer is
In the refractive index ellipsoid formed by the first retardation layer, in the wavelength λ = 400 to 700 nm range,
nx1 (λ)> ny1 (λ) ≈nz1 (λ)
[Wherein, nx1 (λ) represents a main refractive index in a direction parallel to the film plane with respect to light of wavelength λ (nm) in the refractive index ellipsoid formed by the first retardation layer. ny1 (λ) is a refractive index ellipsoid formed by the first retardation layer and is parallel to the film plane and has a wavelength λ (nm) in a direction perpendicular to the direction of nx1 (λ). Represents the refractive index of light. In the refractive index ellipsoid formed by the first retardation layer, nz1 (λ) represents a refractive index in a direction perpendicular to the film plane with respect to light having a wavelength λ (nm). ]
Have the relationship
The optical film as described in [1], which satisfies the relationship of the following formulas (3) and (4).
Re1 (450) / Re1 (550) ≦ 1.00 (3)
1.00 ≦ Re1 (650) / Re1 (550) (4)
[Where Re1 (450) is the in-plane retardation value of the first retardation layer for light of wavelength λ = 450 nm, and Re1 (550) is the in-plane position of the first retardation layer for light of wavelength λ = 550 nm. The phase difference value Re1 (650) indicates the in-plane retardation value of the first retardation layer with respect to the light with the wavelength λ = 650 nm, and the in-plane retardation value Re1 (λ with respect to the light with the wavelength λnm. )
Re1 (λ) = (nx1 (λ) −ny1 (λ)) × d1
It is represented by Here, d1 represents the thickness of the first retardation layer. ]

[3] The second retardation layer is
In the refractive index ellipsoid formed by the second retardation layer, in the wavelength λ = 400 to 700 nm range,
nz2 (λ)> nx2 (λ) ≈ny2 (λ)
[Wherein, nz2 (λ) represents the refractive index in the direction perpendicular to the film plane with respect to light of wavelength λ (nm) in the refractive index ellipsoid formed by the second retardation layer. In the refractive index ellipsoid formed by the second retardation layer, nx2 (λ) represents the maximum refractive index in a direction parallel to the film plane with respect to light having a wavelength λ (nm). ny2 (λ) is a refractive index ellipsoid formed by the second retardation layer, and is parallel to the film plane and with respect to light having a wavelength λ (nm) in a direction orthogonal to the nx2 direction. Refractive index. However, when nx2 (λ) = ny2 (λ), nx2 (λ) represents a refractive index in an arbitrary direction parallel to the film plane. ]
Have the relationship
The optical film according to [1] or [2], which satisfies the relationship of the following formulas (5) and (6).
Rth2 (450) / Rth2 (550) ≦ 1.00 (5)
1.00 ≦ Rth2 (650) / Rth2 (550) (6)
[Where Rth2 (450) is the thickness direction retardation value for light of wavelength λ = 450 nm, and Rth2 (550) is the thickness direction retardation value of the second retardation layer for light of wavelength λ = 550 nm. , Rth2 (650) represents a retardation value in the thickness direction of the second retardation layer with respect to light having a wavelength of 650 nm, and a retardation value Rth2 in the thickness direction of the second retardation layer with respect to light having a wavelength λ (nm). (Λ) is
Rth2 (λ) = [(nx2 (λ) + ny2 (λ)) / 2−nz2 (λ)] × d2
It is represented by Here, in the refractive index ellipsoid formed by the second retardation layer, nz2 (λ) represents the main 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 on the film plane at the wavelength λ (nm). d2 represents the thickness of the second retardation layer. ]

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

[5] The optical film according to any one of [1] to [4], wherein the second retardation layer further has optical characteristics represented by the formula (9).
−100 nm ≦ Rth2 (550) ≦ −50 nm (8)
[Wherein Rth2 (550) represents a retardation value in the thickness direction of the second retardation layer with respect to light having a wavelength λ = 550 nm. ]

[6] The optical film as described in any one of [1] to [5] above, which is a film comprising a coating layer formed by polymerizing the polymerizable liquid crystal in a state where the second retardation layer is oriented.

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

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

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

[10] The above-mentioned [1] to [9], wherein the first retardation layer and the second retardation layer are coating layers formed by mainly polymerizing the same polymerizable liquid crystal compound. Optical film.

[11] An elliptically polarizing plate with an optical compensation function, comprising the optical film according to any one of [1] to [10] 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. The elliptically polarizing plate with an optical compensation function according to the above [11], wherein the slow axis of the retardation layer and the slow axis of the second retardation layer are perpendicular to the film surface.

[13] The above [11] or [12], 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 above [11] or [12], 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].

The manufacturing method of the elliptically polarizing plate with an optical compensation function in any one of said [11]-[14] with an optical compensation function including all the following processes.
(Step 1-A) After applying a polymerizable liquid crystal compound on a substrate on which a horizontal alignment film is formed, a step of forming a retardation layer by polymerizing in a horizontally aligned state;
(Step 1-B) A step of forming a second retardation layer by applying a polymerizable liquid crystal compound on a substrate on which a vertical alignment film is formed, and then polymerizing 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 via an adhesive and laminating them on the polarizing plate

  ADVANTAGE OF THE INVENTION According to this invention, the novel optical film by which the optical refractive index was controlled by the three-dimensional direction with respect to all the visible light whole areas and all the directions visually recognized, and its manufacturing method are provided. Furthermore, the present invention provides a liquid crystal display device and an organic EL display device that enable clear display display by using this optical film.

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

  The optical film of the present invention comprises a first retardation layer and a second retardation layer. The first retardation layer and the second retardation layer may be formed by a method of stretching or shrinking the polymer film, but from the viewpoint of thinning, a polymerizable liquid crystal (hereinafter also referred to as a polymerizable liquid crystal compound). .) Is preferably a film comprising a coating layer formed by polymerizing in an oriented state.

The first retardation layer and the second retardation layer are formed by applying a composition containing a polymerizable liquid crystal compound (hereinafter also referred to as “a retardation layer forming composition”) onto a transparent substrate. It is preferable to use a polymer in the alignment state of the polymerizable liquid crystal compound by heating and cooling treatment from the viewpoint that the thickness can be reduced and the wavelength dispersion characteristics can be arbitrarily designed. Further, as will be described later, the retardation layer forming composition 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 cured in a state where the polymerizable liquid crystal compound is aligned in the horizontal direction with respect to the substrate surface, and the second retardation layer is formed of the polymerizable liquid crystal compound as the substrate. A liquid crystal cured film cured in a state of being oriented in a direction perpendicular to the surface is preferable.

In the first retardation layer, Re1 (550) that is an in-plane retardation value for light having a wavelength of 550 nm preferably satisfies the optical characteristics represented by the following formula (7). The first retardation layer has an in-plane retardation value Re1 (450) for light with a wavelength of 450 nm, an in-plane retardation value Re1 (550) for light with a wavelength of 550 nm, and a surface for light with a wavelength of 650 nm. It is also preferable that Re1 (650), which is the internal phase difference value, satisfies the optical characteristics represented by the expressions (3) and (4). It is more preferable that the first retardation layer satisfies the optical characteristics represented by the following formula (7), the following formula (3), and the following formula (4).
120 nm ≦ Re1 (550) ≦ 170 nm (7)
(In the formula, Re1 (550) represents an in-plane retardation value (in-plane retardation) with respect to light having a wavelength of 550 nm of the first retardation layer.)
Re1 (450) / Re1 (550) ≦ 1.0 (3)
1.00 ≦ Re1 (650) / Re1 (550) (4)
(Where Re1 (450) is the in-plane retardation value for light having a wavelength of 450 nm of the first retardation layer, and Re1 (550) is the in-plane retardation value for light having a wavelength of 550 nm of the first retardation layer. Re1 (650) represents the in-plane retardation value for the light of wavelength 650 nm of the first retardation layer.)
When the in-plane retardation value Re1 (550) of the first retardation layer exceeds the range of the formula (7), there may be a problem that the front hue turns 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 provided with the retardation layer becomes large. Preferably they are 0.75 or more and 0.92 or less, More preferably, they are 0.77 or more and 0.87 or less, More preferably, they are 0.79 or more and 0.85 or less.

The in-plane retardation value of the first retardation layer can be adjusted by the thickness of the retardation layer. Since the in-plane retardation value is determined by the following formula (A), a desired in-plane retardation value (Re1 (λ): in-plane retardation value of the first retardation layer at the wavelength λ (nm)) Is obtained by adjusting the three-dimensional refractive index and the film thickness d1. The thickness of the retardation layer is preferably 0.5 μm to 5 μm, and more preferably 1 μm to 3 μm. The thickness of the retardation layer can be measured with an interference film thickness meter, a laser microscope or a stylus thickness meter. The three-dimensional refractive index depends on the molecular structure and orientation state of the polymerizable liquid crystal compound described later.
Re1 (λ) = (nx1 (λ) −ny1 (λ)) × d1 (A)
(In the formula, the refractive index ellipsoid formed by the first retardation layer has a relationship of nx1 (λ)> ny1 (λ) ≈nz1 (λ), where nx1 (λ) is light of wavelength λ (nm). Ny1 (λ) is a refractive index ellipsoid formed by the first retardation layer for light of wavelength λ (nm) and parallel to the film plane. And represents the refractive index in the direction orthogonal to the direction of nx1 (λ), and 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 characteristics represented by the following formula (8). Moreover, it is also preferable to satisfy the optical characteristics represented by the following formulas (5) and (6). It is more preferable that the second retardation layer satisfies the optical characteristics represented by the following formula (8), the following formula (5), and the following formula (6).
−100 nm ≦ Rth2 (550) ≦ −50 nm (8)
(In the formula, Rth2 (550) represents a retardation value in the thickness direction with respect to light having a wavelength of 550 nm.)
Rth2 (450) / Rth2 (550) ≦ 1.0 (5)
1.00 ≦ Rth2 (650) / Rth2 (550) (6)
(Where Rth2 (450) is the thickness direction retardation value for light with a wavelength of 450 nm, Rth2 (550) is the same meaning as above, and Rth2 (650) is the thickness direction retardation value for light with a wavelength of 650 nm. Represent each.)
When the retardation value Rth2 (550) in the thickness direction of the second retardation layer exceeds the range of the formula (8), there is a problem that 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 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 provided with the retardation layer becomes large. Preferably they are 0.75 or more and 0.92 or less, More preferably, they are 0.77 or more and 0.87 or less, More preferably, they are 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 retardation value in the desired thickness direction (Rth2 (λ): in-plane retardation value of the second retardation layer at the 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, and more preferably 0.5 μm to 2 μm. The thickness of the retardation layer can be measured with an interference film thickness meter, a laser microscope or a stylus thickness meter. The three-dimensional refractive index depends on the molecular structure and orientation of the polymerizable liquid crystal compound 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 a relationship of nz2 (λ)> nx2 (λ) ≈ny2 (λ), where nz2 (λ) is the second order. In the refractive index ellipsoid formed by the phase difference layer, the refractive index in the direction perpendicular to the film plane with respect to light of wavelength λ (nm) is represented, where nx2 (λ) is the refractive index ellipse formed by the second phase difference layer. Is the maximum refractive index in the direction parallel to the film plane for light of wavelength λ (nm), and ny2 (λ) is the refractive index ellipsoid formed by the second retardation layer on the film plane. Refractive index for light having a wavelength λ (nm) parallel to the direction of nx2 and perpendicular to the direction of nx2 represents nx2 (λ) = ny2 (λ). (Λ) represents the refractive index in an arbitrary direction parallel to the film plane. In this, d2 represents the thickness of the second retardation layer.)

The optical film of this invention has a 1st phase difference layer and a 2nd phase difference layer, and satisfy | fills the relationship of following formula (1) and (2).
0.40 ≦ Nz (450) ≦ 0.60 (1)
0.40 ≦ Nz (550) ≦ 0.60 (2)
(Where Nz (λ) is an Nz coefficient indicating the relationship of the three-dimensional refractive index with respect to light of wavelength λ (nm), and Nz (λ) = (nx (λ) −nz (λ)) / (nx ( λ) −ny (λ)) where nx (λ) represents the main refractive index in the direction parallel to the film plane for light of wavelength λ (nm) in the refractive index ellipsoid formed by the optical film. Ny (λ) is a refractive index ellipsoid formed by the optical film and is parallel to the plane of the film with respect to light of wavelength λ (nm) and orthogonal to the direction of nx (λ). (Nz (λ) represents the refractive index in the direction perpendicular to the plane of the film with respect to light of wavelength λ (nm) in the refractive index ellipsoid formed by the optical film.)
That is, the optical film of the present invention has a three-dimensional refractive index relationship of nx (λ)> nz (λ)> ny (λ), and the optical film has the relationship of the formulas (1) and (2). When a display is mounted, it can give display characteristics with excellent hue. Nz (λ) is more preferably 0.45 ≦ Nz (450) ≦ 0.55 and 0.45 ≦ Nz (550) ≦ 0.55, respectively. Here, Nz (450) represents the Nz coefficient at the wavelength λ = 450 nm, and Nz (550) represents the Nz coefficient at the 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 equation.
Nz (λ) = (nx (λ) −nz (λ)) / (nx (λ) −ny (λ))
Further, when calculating the Nz coefficient of the optical film, when 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)
(Where 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). The phase difference value, Rth1 (λ) is the thickness direction retardation value of the first retardation layer at the wavelength λ (nm), and Rth2 (λ) is the second retardation layer of the wavelength λ (nm). (This is the retardation 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 an active radical or an acid generated from a photopolymerization initiator. Examples of the photopolymerizable functional group include a vinyl group, vinyloxy group, 1-chlorovinyl group, isopropenyl group, 4-vinylphenyl group, acryloyloxy group, methacryloyloxy group, oxiranyl group, and oxetanyl group. Among them, acryloyloxy group, methacryloyloxy group, vinyloxy group, oxiranyl group and oxetanyl group are preferable, and acryloyloxy group is more preferable. The thermic liquid crystal may be either a thermotropic liquid crystal or a lyotropic liquid crystal, but the thermotropic liquid crystal is preferred in terms of enabling precise film thickness control. The phase order structure in the thermotropic liquid crystal may be a nematic liquid crystal or a smectic liquid crystal.

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

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

G ¹ and G ² are each independently preferably a 1,4-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. 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, more preferably 1 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 A substituted 1,4-trans-cyclohexanediyl group.
In addition, at least one of a plurality of G ¹ and G ² is preferably a divalent alicyclic hydrocarbon group, and at least one of G ¹ and G ² bonded to L ¹ or L ² More preferably, it is a divalent alicyclic hydrocarbon group.

L ¹ and L ² are each independently preferably a single bond, 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 each 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 —. is there. 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 a single bond, —O—, —CH ₂ CH ₂ —, —COO—, —COOCH ₂ CH ₂ —, or —OCO—.

B ¹ and B ² are preferably 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 —. is there. 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 are preferably in the range of 2 ≦ k + l ≦ 6 from the viewpoint of expression of inverse wavelength dispersion, preferably k + l = 4, and more preferably k = 2 and l = 2. It is 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, and more preferably an alkanediyl group having 4 to 12 carbon atoms.

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

  Ar preferably has 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, and an anthracene ring, and a benzene ring and a naphthalene ring are preferable. Examples of the aromatic heterocycle include furan ring, benzofuran ring, pyrrole ring, indole ring, thiophene ring, benzothiophene ring, pyridine ring, pyrazine ring, pyrimidine ring, triazole ring, triazine ring, pyrroline ring, imidazole ring, pyrazole ring. , Thiazole ring, benzothiazole ring, thienothiazole ring, oxazole ring, benzoxazole ring, phenanthrolin ring, and the like. Of these, a thiazole ring, a benzothiazole ring, or a benzofuran ring is preferable, and a benzothiazole group is more preferable. In addition, when Ar includes a nitrogen atom, the nitrogen atom preferably has π electrons.

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, particularly Preferably it is 16 or more. Moreover, Preferably it is 30 or less, More preferably, it is 26 or less, More preferably, it is 24 or less.

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

In formula (Ar-1) to formula (Ar-22), * represents a linking part, and Z ⁰ , Z ¹ and Z ² are each independently a hydrogen atom, a halogen atom, or an alkyl having 1 to 12 carbon atoms. Group, cyano group, nitro group, alkylsulfinyl group having 1 to 12 carbon atoms, alkylsulfonyl group having 1 to 12 carbon atoms, carboxyl group, fluoroalkyl group having 1 to 12 carbon atoms, alkoxy group having 1 to 6 carbon atoms, C1-C12 alkylthio group, C1-C12 N-alkylamino group, C2-C12 N, N-dialkylamino group, C1-C12 N-alkylsulfamoyl group or carbon The N, N-dialkylsulfamoyl group represented by Formula 2 to 12 is represented.

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

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

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

Q ¹ , Q ² and Q ³ are preferably —NH—, —S—, —NR ^{2 ′} — and —O—, and R ^{2 ′} is preferably a hydrogen atom. Among them, -S-, -O-, and -NH- are particularly preferable.

Among formulas (Ar-1) to (Ar-22), formula (Ar-6) and formula (Ar-7) are preferable 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 described above as the aromatic heterocyclic ring that Ar may have, for example, pyrrole ring, imidazole ring, pyrroline ring, pyridine ring, pyrazine ring, pyrimidine ring, indole Ring, quinoline ring, isoquinoline ring, purine ring, pyrrolidine ring and the like. This aromatic heterocyclic group may have a substituent. Y ¹ may be the above-described optionally substituted polycyclic aromatic hydrocarbon group or polycyclic aromatic heterocyclic group together with the nitrogen atom to which it is bonded and Z ⁰ . For example, a benzofuran ring, a benzothiazole ring, a benzoxazole ring, etc. are mentioned.

  The total content of the polymerizable liquid crystal compound in the solid content of 100 parts by mass of the composition for forming a retardation layer is usually 70 parts by mass to 99.5 parts by mass, and preferably 80 parts by mass to 99 parts by mass. Part, more preferably 80 parts by weight to 94 parts by weight, and still more preferably 80 parts by weight to 90 parts by weight. If the total content is within the above range, the orientation of the obtained retardation layer tends to be high. Here, solid content means the total amount of the component remove | excluding the solvent from the composition.

[solvent]
As the solvent, a solvent capable of dissolving the polymerizable liquid crystal compound is preferable, and a solvent inert to the polymerization reaction of the polymerizable liquid crystal compound is preferable.
Examples of the solvent include alcohol solvents such as 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, ethylene glycol methyl ether acetate. Ester solvents such as 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 solvent; Aromatic hydrocarbon solvent such as toluene and xylene; Nitrile solvent such as acetonitrile; Tetra Ether solvents such as drofuran and dimethoxyethane; chlorine-containing solvents such as chloroform and chlorobenzene; amide solvents such as dimethylacetamide, dimethylformamide, N-methyl-2-pyrrolidone and 1,3-dimethyl-2-imidazolidinone Etc. These solvents may be used alone or in combination of two or more. Among these, alcohol solvents, ester solvents, ketone solvents, chlorine-containing solvents, amide solvents, and aromatic hydrocarbon solvents are preferable.

  50 mass parts-98 mass parts are preferable, and, as for content of the solvent which occupies for 100 mass parts of compositions, 70 weight part-95 weight part are more preferable. 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 becomes low, so that the thickness of the retardation layer becomes substantially uniform and unevenness in the retardation layer tends not to occur. The solid content can be appropriately determined in consideration of the thickness of the retardation layer to be produced.

<Polymerization initiator>
The polymerization initiator is a compound capable of generating a reactive species by the contribution of heat or light and initiating a polymerization reaction such as a polymerizable liquid crystal. Examples of reactive species include active species such as radicals, cations, and anions. Among these, from the viewpoint of easy reaction control, a photopolymerization initiator that generates radicals by light irradiation is preferable.
Examples of the photopolymerization initiator include benzoin compounds, benzophenone compounds, benzyl ketal compounds, α-hydroxy ketone compounds, α-amino ketone compounds, triazine compounds, iodonium salts, and sulfonium salts. Specifically, Irgacure (registered trademark) 907, Irgacure 184, Irgacure 651, Irgacure 819, Irgacure 250, Irgacure 369, Irgacure 379, Irgacure 127, Irgacure 2959, Irgacure 754, Irgacure 379EG (above, BASF Japan Ltd.) ), Sequol BZ, Sequol Z, Sequol BEE (above, Seiko Chemical Co., Ltd.), kayacure BP100 (Nippon Kayaku Co., Ltd.), Kayacure UVI-6992 (Dow), Adekaoptomer SP- 152, Adekaoptomer SP-170, Adekaoptomer N-1717, Adekaoptomer N-1919, Adeka Arcles NCI-831, Adeka Arcles NCI-930 (above, stocks Company ADEKA), TAZ-A, TAZ-PP (above, made by Nippon Siebel Hegner) and TAZ-104 (made by Sanwa Chemical Co., Ltd.).
In the composition for forming a retardation layer, the photopolymerization initiator contained is at least one, and preferably one or two.

The photopolymerization initiator can sufficiently utilize the energy emitted from the light source and is excellent in productivity. Therefore, the maximum absorption wavelength is preferably 300 nm to 400 nm, more preferably 300 nm to 380 nm, and among them, α-acetophenone series A polymerization initiator and an oxime photopolymerization initiator are preferred.

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

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

  The addition amount of the photopolymerization initiator is usually 0.1 part by mass to 30 parts by mass, preferably 1 part by mass to 20 parts by mass, and more preferably 1 part per 100 parts by mass of the polymerizable liquid crystal compound. Part by mass to 15 parts by mass. If it is in the said range, reaction of a polymeric group will fully advance and it will be hard to disturb the orientation of a polymeric liquid crystal compound.

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

Furthermore, the sensitivity of the photopolymerization initiator can be increased by using a sensitizer. Examples of the photosensitizer include xanthones such as xanthone and thioxanthone; anthracene having a substituent such as anthracene and alkyl ether; phenothiazine; and rubrene. Examples of the photosensitizer include xanthones such as xanthone and thioxanthone; anthracene having a substituent such as anthracene and alkyl ether; phenothiazine; and rubrene. Content of a photosensitizer is 0.01-10 mass parts normally with respect to 100 mass parts of polymeric liquid crystal compounds, Preferably it is 0.05-5 mass parts, More preferably, it is 0.1-10 mass parts. 3 parts by mass.

[Leveling agent]
The leveling agent is an additive having a function of adjusting the fluidity of the composition and flattening a film obtained by applying the composition. For example, silicone-based and polyacrylate-based silane coupling agents, etc. And perfluoroalkyl leveling agents. Specifically, DC3PA, SH7PA, DC11PA, SH28PA, SH29PA, SH30PA, ST80PA, ST86PA, SH8400, SH8700, FZ2123 (all are manufactured by Toray Dow Corning Co., Ltd.), KP321, KP323, KP324, KP326, KP340, KP341, X22-161A, KF6001, KBM-1003, KBE-1003, KBM-303, KBM-402, KBM-403, KBE-402, KBE-403, KBM-1403, KBM-502, KBM-503, KBE- 502, KBE-503, KBM-5103, KBM-602, KBM-603, KBM-903, KBE-903, KBE-9103, KBM-573, KBM-575, KBE-585, KBM-80 , 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 (and above) , All by Momentive Performance Materials Japan LLC), Fluorinert (registered trademark) FC-72, FC-40, FC-43, FC-3283 (all above, all made by Sumitomo 3M), Megafuck (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 of which are DIC Manufactured), F-top (trade name) EF301, EF303, EF351, EF351, EF352 (all manufactured by Mitsubishi Materials Electronic Chemical Co., Ltd.), Surflon (registered trademark) S-381, S-382, S- 383, S-393, SC-101, SC-105, KH-40, SA-100 (all of which are manufactured by AGC Seimi Chemical Co., Ltd.), trade names E1830, E5844 (Daikin Fine Chemical Co., Ltd.) Manufactured), BM-1000, BM-1100, BYK-352, BYK-353, and BYK-361N (all trade names: manufactured by BM Chemie).

The content of the leveling agent in the retardation layer forming composition is preferably 0.01 parts by mass to 5 parts by mass, and more preferably 0.05 parts by mass to 3 parts by mass with respect to 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 obtained retardation layer tends to be smoother. The composition for forming the retardation layer may contain two or more leveling agents.

[Base material]
As a base material, a glass base material and a film base material are mentioned, A film base material is preferable from a viewpoint of workability, and a long roll-shaped film is more preferable at the point which can be manufactured continuously. Examples of the resin constituting the film substrate include polyolefins such as polyethylene, polypropylene, norbornene polymers, cyclic olefin resins, polyvinyl alcohol, polyethylene terephthalate, polymethacrylates, polyacrylates, triacetylcellulose, and diacetylcellulose. And cellulose esters such as cellulose acetate propionate; polyethylene naphthalate; polycarbonate; polysulfone; polyethersulfone; polyetherketone; polyphenylene sulfide and polyphenylene oxide;
Examples of the commercially available cellulose ester base material include “Fujitac Film” (manufactured by Fuji Photo Film Co., Ltd.);
Commercially available cyclic olefin-based resins include “Topas” (registered trademark) (manufactured by Ticona (Germany)), “Arton” (registered trademark) (manufactured by JSR Corporation), “ZEONOR” (registered trademark), “ZEONEX” (registered trademark) (manufactured by Nippon Zeon Co., Ltd.) and “Apel” (registered trademark) (manufactured by Mitsui Chemicals, Inc.) can be mentioned. Such a cyclic olefin-based resin can be formed into a substrate by forming a film by a known means such as a solvent casting method or a melt extrusion method. Commercially available cyclic olefin resin base materials can also be used. Commercially available cyclic olefin-based resin base materials include “Essina” (registered trademark), “SCA40” (registered trademark) (manufactured by Sekisui Chemical Co., Ltd.), “Zeonor Film” (registered trademark) (manufactured by Optes Corporation). ) And “Arton Film” (registered trademark) (manufactured by JSR Corporation).
The thickness of the substrate is preferably as thin as possible so that it can be handled practically, but if it is too thin, the strength tends to decrease and the processability tends to be poor. The thickness of a base material is 5 micrometers-300 micrometers normally, Preferably it is 20 micrometers-200 micrometers. Further, a further thinning effect can be obtained by removing only the polymer in the alignment state of the polymerizable liquid crystal compound by peeling the base material.

[Alignment film]
An alignment film is preferably formed on the surface of the substrate on which the retardation layer forming composition is applied. The alignment film has an alignment regulating force for aligning the polymerizable liquid crystal compound in a desired direction.

  The alignment film has solvent resistance that does not dissolve due to the application of the retardation layer forming composition, etc., and also has heat resistance in heat treatment for solvent removal and alignment of the polymerizable liquid crystal compound described below. preferable.

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

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

  An alignment polymer can be used for the rubbing alignment film. Examples of the orientation polymer include polyamides and gelatins having amide bonds, polyimides having imide bonds, and polyamic acids, polyvinyl alcohols, alkyl-modified polyvinyl alcohols, polyacrylamides, polyoxazoles, polyethyleneimines, polystyrenes having imide bonds. , Polyvinyl pyrrolidone, polyacrylic acid and polyacrylic acid esters. Two or more kinds of orientation polymers may be combined.

  A rubbing alignment film is usually formed by applying a composition in which an alignment polymer is dissolved in a solvent (hereinafter also referred to as an alignment polymer composition) to a substrate, removing the solvent to form a coating film, By rubbing, an alignment regulating force can be applied.

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

  Oriented polymer compositions are commercially available. Examples of the commercially available oriented polymer composition include Sanever (registered trademark, manufactured by Nissan Chemical Industries, Ltd.), Optmer (registered trademark, manufactured by JSR).

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

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

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

  The photoreactive group refers to a group that generates alignment ability when irradiated with light. Specific examples include groups that are involved in photoreactions that are the origin of alignment ability, such as alignment-induced reactions, isomerization reactions, photodimerization reactions, photocrosslinking reactions, or photodecomposition reactions of molecules generated by light irradiation. As the photoreactive group, an unsaturated bond, particularly a group having a double bond is preferable, and a carbon-carbon double bond (C = C bond), a carbon-nitrogen double bond (C = N bond), and nitrogen-nitrogen. A group having at least one selected from the group consisting of a double bond (N═N bond) and a carbon-oxygen double bond (C═O bond) is particularly preferred.

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

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

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

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

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

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

The groove alignment film is a film having a concavo-convex pattern or a plurality of grooves (grooves) on the film surface. When a polymerizable liquid crystal compound is applied to a film having a plurality of linear grooves arranged at equal intervals, liquid crystal molecules are aligned in a direction along the groove.
As a method for obtaining a groove alignment film, a method of forming a concavo-convex pattern by performing development and rinsing after exposure through an exposure mask having a pattern-shaped slit on the photosensitive polyimide film surface, a plate having grooves on the surface A method of forming a UV curable resin layer before curing on a sheet-shaped master, transferring the resin layer to a substrate and curing, and a plurality of UV curable resin films before curing formed on the substrate, Examples include a method in which a roll-shaped master having a groove is pressed to form irregularities and then cured.

  The thickness of the alignment film for forming the first retardation layer is usually in the range of 10 to 10000 nm, preferably in the range of 10 to 1000 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 applied. As the vertical alignment film, it is preferable to apply a material that lowers the surface tension of the substrate surface. Examples of such materials include the above-described orientation polymers and fluorine-based polymers such as perfluoroalkyl, polyimide compounds, silane compounds, and polysiloxane compounds obtained by a condensation reaction thereof. Silane compounds are preferred because they tend to reduce the surface tension.

  As the silane compound, silicones such as the above-mentioned silane coupling agents can be suitably applied. For example, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane, N- (2- Aminoethyl) -3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycyl Sidoxypropylmethyldimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-mercap Trimethoxysilane, 3-glycidoxypropyl trimethoxysilane, 3-glycidoxypropyl triethoxysilane, 3-glycidoxypropyl dimethoxymethyl silane, such as 3-glycidoxypropyl ethoxy dimethyl silane. Two or more silane compounds may be used.

  The silane compound may be of a silicone monomer type or a type silicone oligomer (polymer) type. When the silicone oligomer is shown in the form of (monomer)-(monomer) copolymer, for example, the following can be mentioned.

  3-mercaptopropyltrimethoxysilane-tetramethoxysilane copolymer, 3-mercaptopropyltrimethoxysilane-tetraethoxysilane copolymer, 3-mercaptopropyltriethoxysilane-tetramethoxysilane copolymer, and 3-mercaptopropyltriethoxysilane-tetraethoxy A copolymer containing a mercaptopropyl group, such as a silane copolymer;

  Mercaptomethyl groups such as mercaptomethyltrimethoxysilane-tetramethoxysilane copolymer, mercaptomethyltrimethoxysilane-tetraethoxysilane copolymer, mercaptomethyltriethoxysilane-tetramethoxysilane copolymer, and mercaptomethyltriethoxysilane-tetraethoxysilane copolymer. Containing copolymers;

  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 3-methacryloxyyl propylmethyldiethoxysilane-tetra Toki bell Ranco polymers such as, methacryloyloxypropyl group containing 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 3-acryloyloxypropylmethyldiethoxysilane-tetraethoxysilane Rimmer such as, acryloyloxypropyl group-containing copolymer;

  Vinyltrimethoxysilane-tetramethoxysilane copolymer, vinyltrimethoxysilane-tetraethoxysilane copolymer, vinyltriethoxysilane-tetramethoxysilane copolymer, vinyltriethoxysilane-tetraethoxysilane copolymer, vinylmethyldimethoxysilane-tetramethoxysilane copolymer, Vinyl group-containing copolymers such as vinylmethyldimethoxysilane-tetraethoxysilane copolymer, vinylmethyldiethoxysilane-tetramethoxysilane copolymer, and vinylmethyldiethoxysilane-tetraethoxysilane copolymer;

  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-aminopropylmethyldiethoxy Amino group-containing copolymers such as silane-tetraethoxysilane copolymers.

Among them, a silane compound having an alkyl group at the molecular end is preferable, and a silane compound having an alkyl group having 6 to 20 carbon atoms is more preferable. Since these silane compounds are often liquids, they may be applied to the substrate as they are, or may be dissolved in a solvent and applied to the substrate. Moreover, you may melt | dissolve in a solvent and apply | coat to a base material with various polymers as a binder.

  Examples of the method for applying the vertical alignment film to the substrate include the same method as the method for applying the retardation layer forming composition described later to the substrate. Examples of the method for removing the solvent from the applied composition for forming a photo-alignment film include the same method as the method for removing the solvent from the oriented polymer composition.

  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 5000 nm, and more preferably in the range of 100 to 500 nm.

≪Method for producing retardation layer≫
<Coating of composition for forming retardation layer>
A retardation layer can be formed by applying the composition for forming a retardation layer on the substrate or the alignment film. As a method for applying the retardation layer forming composition on the substrate, extrusion coating method, direct gravure coating method, reverse gravure coating method, CAP coating method, slit coating method, micro gravure method, die coating method, inkjet method Etc. Moreover, the method of apply | coating using coaters, such as a dip coater, a bar coater, a spin coater, etc. are mentioned. In particular, when applying continuously in the Roll to Roll format, a coating method by a microgravure method, an ink jet method, a slit coating method, or a die coating method is preferable, and when applying to a single-wafer substrate such as glass, uniformity is achieved. A high spin coating method is preferred.

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

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

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

Ultraviolet irradiation intensity is ^{usually, 10mW / cm 2 ~3,000mW / cm} 2. The ultraviolet irradiation intensity is preferably an intensity in a wavelength region effective for activating the cationic polymerization initiator or radical polymerization initiator. The time for irradiating 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 irradiating once or a plurality of times with such ultraviolet irradiation intensity, the integrated light quantity 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 . When the integrated light quantity is less than this range, the polymerizable liquid crystal compound is not sufficiently cured, and good transferability may not be obtained. On the contrary, when the integrated light quantity is more than this range, the optical film including the retardation layer may be colored.

[Polarizer]
The elliptically polarizing plate of the present invention comprises a polarizing plate and the optical film of the present invention. For example, the polarizing plate and the optical film of the present invention are bonded together via an adhesive or an adhesive layer. Thus, the elliptically polarizing plate of the present invention can be obtained.
In one embodiment of the present invention, when the 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 substantially 45 °. It is preferable to laminate 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 as to be substantially 45 °, a 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 in which a dye having absorption anisotropy is adsorbed, or a film in which a dye having absorption anisotropy is applied and oriented. Examples of the dye having absorption anisotropy include a dichroic dye.

  A stretched film on which a dye having absorption anisotropy is adsorbed is usually a step of uniaxially stretching a polyvinyl alcohol resin film, and the dichroic dye is dyed by dying the polyvinyl alcohol resin film. It is manufactured through a step of adsorbing, a step of treating a polyvinyl alcohol-based resin film adsorbed with a dichroic dye with an aqueous boric acid solution, and a step of washing with water after the treatment with an aqueous boric acid solution. A polarizing plate is obtained by laminating the thus obtained polarizer and a transparent protective film. Examples of the dichroic dye include iodine and dichroic organic dyes. Examples of the dichroic organic dye include dichroic direct dyes composed of disazo compounds such as C.I. DIRECT RED 39, and dichroic direct dyes composed of compounds such as trisazo and tetrakisazo. As described above, the thickness of a polarizer obtained by subjecting a polyvinyl alcohol resin film to uniaxial stretching, dyeing with a dichroic dye, boric acid treatment, water washing 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 the display device include pressure-sensitive adhesives, dry-solidifying adhesives, and chemically reactive adhesives. Examples of the chemically reactive adhesive include an active energy ray curable adhesive. As the adhesive between the polarizing plate and the optical film of the present invention, an adhesive layer formed from a pressure-sensitive adhesive, a dry-solidifying adhesive, and an active energy ray-curable adhesive is preferable. As the adhesive between the optical film and the display device, a pressure sensitive adhesive or an active energy ray curable adhesive is preferable.

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

  As an acrylic polymer, (meth) acrylate (hereinafter referred to as (meth) acrylate is a generic term for (meth) acrylate) in which the alkyl group in the ester moiety is an alkyl group having 1 to 20 carbon atoms such as a methyl group, an ethyl group or a butyl group. Acrylic acid and methacrylic acid may be collectively referred to as (meth) acrylic acid) and (meth) having a functional group such as (meth) acrylic acid or hydroxyethyl (meth) acrylate A copolymer with an acrylic monomer is preferred.

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

Examples of the solvent include the solvents mentioned as the solvent. The pressure-sensitive adhesive may contain a light diffusing agent. The light diffusing agent is an additive that imparts light diffusibility to the pressure-sensitive adhesive, and may be fine particles having a refractive index different from the refractive index of the polymer included in the pressure-sensitive adhesive. Examples of the light diffusing agent include fine particles made of an inorganic compound and fine particles made of an organic compound (polymer). Since many of the polymers that the pressure-sensitive adhesive contains as an active ingredient, including acrylic polymers, have a refractive index of about 1.4 to 1.6, the light diffusing agent has a refractive index of 1.2 to 1.8. It is preferable to select appropriately. The refractive index difference between the polymer contained in the pressure-sensitive adhesive as an active ingredient and the light diffusing agent is usually 0.01 or more, and is preferably 0.01 to 0.2 from the viewpoint of the brightness and display properties of the display device. The fine particles used as the light diffusing agent are preferably spherical fine particles, or fine particles close to monodisperse, and more preferably fine particles having an average particle diameter of 2 μm to 6 μm. The refractive index is measured by a general minimum deviation method or Abbe refractometer.
Examples of the fine particles made of an inorganic compound include aluminum oxide (refractive index 1.76) and silicon oxide (refractive index 1.45). Fine particles comprising an organic compound (polymer) include melamine beads (refractive index 1.57), polymethyl methacrylate beads (refractive index 1.49), methyl methacrylate / styrene copolymer resin beads (refractive index 1.50). To 1.59), polycarbonate beads (refractive index 1.55), polyethylene beads (refractive index 1.53), polystyrene beads (refractive index 1.6), polyvinyl chloride beads (refractive index 1.46), and silicone. Examples thereof include resin beads (refractive index: 1.46). The content of the light diffusing agent is usually 3 to 30 parts by mass with respect to 100 parts by mass of the polymer.
Since the thickness of the pressure-sensitive adhesive is determined according to its adhesion and the like, it is not particularly limited, but is usually 1 μm to 40 μm. From the viewpoints of workability and durability, the thickness is preferably 3 μm to 25 μm, and more preferably 5 μm to 20 μm. By setting the thickness of the adhesive layer formed from the pressure-sensitive adhesive to 5 μm to 20 μm, the brightness of the display device when viewed from the front or obliquely is maintained, and blurring or blurring of the display image is prevented. It can be made difficult to occur.

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

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

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

  Examples of the epoxy resin include a polyamide epoxy resin obtained by reacting a polyalkylenepolyamine such as diethylenetriamine or triethylenetetramine with a dicarboxylic acid such as adipic acid and epichlorohydrin. Commercially available products of such polyamide epoxy resins include “Smiles Resin (registered trademark) 650” and “Smiles Resin 675” (manufactured by Sumika Chemtex Co., Ltd.), “WS-525” (manufactured by Nippon PMC Co., Ltd.). Etc. When mix | blending an epoxy resin, the addition amount is 1 mass part-100 mass parts normally with respect to 100 mass parts of polyvinyl alcohol-type resin, Preferably it is 1 mass part-50 mass parts.

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

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

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

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

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

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

  Hereinafter, the present invention will be described more specifically with reference to examples. In the examples, “%” and “part” mean mass% and part by mass unless otherwise specified. Moreover, the polymer film used in the following Examples, the apparatus, and the measuring method are as follows.

-ZF-14 made from Nippon Zeon Co., Ltd. was used for the cycloolefin polymer (COP) film.
-AGF-B10 made by Kasuga Electric Co., Ltd. was used for the corona treatment device.
The corona treatment was performed once using the above corona treatment device under the conditions of an output of 0.3 kW and a treatment speed of 3 m / min.
-SPOT CURE SP-9 with a polarizer unit made 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 in-plane retardation value Re (λ) was measured using KOBRA-WPR manufactured by Oji Scientific Instruments.
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]
By mixing 5 parts (weight average molecular weight: 30000) and 95 parts of cyclopentanone (solvent) having the following structure as components and stirring the resulting mixture at 80 ° C. for 1 hour, An alignment film composition for forming a retardation layer was obtained.

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

[First and Second Retardation Layer-Forming Composition Preparations (Compositions I to IV)]
0.1 parts of a leveling agent (F-556; manufactured by DIC) and a polymerization initiator 2-dimethylamino-2-based on a mixture of the polymerizable liquid crystal compound A and the polymerizable liquid crystal compound B described below. 6 parts of benzyl-1- (4-morpholinophenyl) butan-1-one (Irgacure 369 (Irg369); manufactured by BASF Japan Ltd.) was added.
Further, 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, thereby forming the first and second retardation layers. A composition was obtained. In addition, the mixture ratio of the polymerizable liquid crystal compound A and the polymerizable liquid crystal compound B is added as shown in Table 1 according to the target 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 the polymerizable liquid crystal compounds A and B is the ratio to the total amount of the polymerizable liquid crystal compounds.

The polymerizable liquid crystal compound A was produced by the method described in JP 2010-31223 A. The polymerizable liquid crystal compound B was produced according to the method described in JP2009-173893. Each molecular structure 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 are added so that the solid content concentration becomes 13%. Cyclopentanone was added to to obtain liquid crystal compositions for forming the 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
[Production of first retardation layer]
On the COP film (ZF-14-50) manufactured by Nippon Zeon Co., Ltd., the alignment film composition for forming the first retardation layer is applied with a bar coater, dried at 80 ° C. for 1 minute, and polarized UV irradiation apparatus ( Using SPOT CURE SP-9 (manufactured by Ushio Electric Co., Ltd.), polarized UV exposure was carried out at an integrated light quantity at a wavelength of 313 nm: 100 mJ / cm ² and an axial angle of 45 °. It was 100 nm when the film thickness of the obtained alignment film for 1st phase difference layer formation was measured with the ellipsometer.
Subsequently, the composition I was applied to the first alignment layer forming alignment film using a bar coater and dried at 120 ° C. for 1 minute, and then a high-pressure mercury lamp (Unicure VB-15201BY-A, USHIO INC.) The first retardation layer is formed by irradiating ultraviolet rays from the surface side where the composition of the retardation layer is applied (manufactured by the company) (irradiated light quantity at a wavelength of 365 nm: 500 mJ / cm ² ) in a nitrogen atmosphere. did. The thickness of the obtained first alignment film for forming a retardation layer was measured with an ellipsometer and found to be 2.3 μm.

[Production of second retardation layer]
On the COP film (ZF-14-50) manufactured by Nippon Zeon Co., Ltd., the alignment film composition for forming the second retardation layer is coated with a bar coater, dried at 120 ° C. for 1 minute, and then the second retardation. A layer forming alignment film was obtained. It was 200 nm when the film thickness of the obtained alignment film for 2nd phase difference layer formation obtained was measured with the ellipsometer.
Subsequently, the composition I was applied to the second alignment layer-forming alignment film using a bar coater and dried at 120 ° C. for 1 minute, and then a high-pressure mercury lamp (Unicure VB-15201BY-A, USHIO INC.) The second retardation layer is formed by irradiating with ultraviolet rays from the side coated with the composition of the retardation layer (integrated light quantity at a wavelength of 365 nm: 500 mJ / cm ² ). did. The thickness of the obtained second alignment layer forming retardation film was measured with an ellipsometer and 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 have a retardation in the cycloolefin polymer film as the substrate. After confirming that there was not, it measured with wavelength (lambda) of 450 nm, 550 nm, and 650 nm with the measuring machine (KOBRA-WR, Oji Scientific Instruments company make), respectively. The obtained results are shown in Table 2.

[Rth measurement of first retardation layer and second retardation layer]
The thickness direction retardation values (Rth1 (λ) and Rth2 (λ)) of the first retardation layer and the second retardation layer produced by the above method have a retardation in the cycloolefin polymer film as the substrate. After confirming that there was no light, the ellipsometer was used to measure the incident angle of light on the sample. In addition, the average refractive index at wavelengths λ of 450 nm and 550 nm was measured using a refractometer (“Multiwave Abbe Refractometer DR-M4” manufactured by Atago Co., Ltd.). Table 2 shows Rth1 (λ) and Rth2 (λ) at wavelengths λ of 450 nm and 550 nm calculated from the obtained film thickness, average refractive index, and ellipsometer measurement results.

[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 the formula (C). The calculated results are shown in Table 2.

The refractive indexes nx1 (λ), ny1 (λ), and nz1 (λ) of the obtained first retardation layer are nx1 (λ)> ny1 (λ) ≈nz1 over the entire wavelength range of λ = 400 to 700 nm. (Λ) is satisfied. 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 of λ = 400 to 700 nm. Meet.

[Production of polarizing plate]
A polyvinyl alcohol film having an average degree of polymerization of about 2,400 and a saponification degree of 99.9 mol% or more and a thickness of 75 μm is immersed in pure water at 30 ° C., and then the weight ratio of iodine / potassium iodide / water is set to be 0.00. Iodine dyeing was performed by immersing in an aqueous solution of 02/2/100 at 30 ° C. (iodine dyeing step). The polyvinyl alcohol film which passed through the iodine dyeing process was immersed in an aqueous solution having a weight ratio of potassium iodide / boric acid / water of 12/5/100 at 56.5 ° C. to perform boric acid treatment (boric acid treatment process). ). The polyvinyl alcohol film that had undergone the boric acid treatment step was washed with pure water at 8 ° C. and then dried at 65 ° C. to obtain a polarizer (thickness 27 μm after stretching) in which iodine was adsorbed and oriented on polyvinyl alcohol. . Under the present circumstances, it extended | stretched in the iodine dyeing process and the boric-acid treatment process. The total draw ratio in such drawing was 5.3 times. The obtained polarizer and a saponified triacetyl cellulose film (Konica Minolta KC4UYTAC 40 μm) were bonded together with a nip roll via an aqueous adhesive. While maintaining the tension of the obtained bonded product at 430 N / m, drying was performed 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 group-modified polyvinyl alcohol (Kuraray Kuraray Poval KL318), and a water-soluble polyamide epoxy resin (Sumites Chemtex Sumirez Resin 650, 30% solid content aqueous solution). Prepared by adding 1.5 parts.

The optical characteristics of the obtained polarizing plate were measured. The measurement was performed with a spectrophotometer (V7100, manufactured by JASCO Corporation) using the polarizer surface of the polarizing plate obtained above as an incident surface. 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 plates]
First, after the corona treatment was performed on the polymerizable liquid crystal compound-coated surface of the first retardation layer, an adhesive (pressure-sensitive adhesive 5 μm manufactured by Lintec Co., Ltd.) was applied to the polarizing plate produced by the method described above. Then, the base material was peeled off to form a laminate of the polarizing plate and the first retardation layer. Subsequently, after the corona treatment is performed on the polymerizable liquid crystal compound coated surface of the second retardation layer, the polarizing plate and the first retardation are bonded via an adhesive (pressure-sensitive adhesive 5 μm manufactured by Lintec Corporation). The first retardation layer and the second retardation layer in the laminate of the layers were bonded. Then, the base material was peeled and the elliptically polarizing plate was manufactured.

[Confirmation of front and oblique hue changes]
The obtained elliptically polarizing plate was bonded to a mirror through an adhesive, and then visually observed 50 cm away from the front to confirm the hue. In addition, an oblique hue was confirmed by visually observing 50 cm away from an elevation angle of 60 ° and an azimuth angle of 0 to 360 °. The confirmed results are shown in Table 2.
The front hue and the oblique hue are as follows.
◎: Clear black, ○: 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 the composition I was changed to the composition II, the composition III, the composition IV, or the composition V, respectively, according to the description in Table 2. Each measurement result is shown in Table 2.
The refractive indexes nx1 (λ), ny1 (λ) and nz1 (λ) of the first retardation layer obtained in Examples 2 to 30 are nx1 (λ )> Ny1 (λ) ≈nz1 (λ). 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 of λ = 400 to 700 nm. Meet.

(Example 31)
Composition I was changed in accordance with the description in Table 2, and the stacking order of the first retardation layer and the second retardation layer in the method for producing an elliptically polarizing plate was changed. First, the polarizing plate and the second retardation layer were changed. After the lamination, an optical film and an elliptically polarizing plate were produced in the same manner as in Example 1 except that the order of laminating the laminate of the polarizing plate and the second retardation layer and the first retardation layer was changed. The measurement results are shown in Table 2.
The refractive indexes nx1 (λ), ny1 (λ), and nz1 (λ) of the first retardation layer obtained in Example 31 are nx1 (λ)> ny1 (wavelength λ = 400 to 700 nm over the entire region. λ) ≈nz1 (λ) is satisfied. 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 of λ = 400 to 700 nm. Meet.

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

Claims (16)

An optical film having a first retardation layer and a second retardation layer and satisfying a relationship 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 of wavelength λ = 450 nm, Nz (550) represents the Nz coefficient of the optical film for light of wavelength λ = 550 nm, and The Nz coefficient Nz (λ) of the optical film with respect to light is Nz (λ) = (nx (λ) −nz (λ)) / (nx (λ) −ny (λ))
Indicated by. In the refractive index ellipsoid formed by the optical film, nx (λ) represents a main refractive index in a direction parallel to the film plane with respect to light having a wavelength λ (nm). ny (λ) is a refractive index in the refractive index ellipsoid formed by the optical film, parallel to the plane of the film with respect to light of wavelength λ (nm) and perpendicular to the direction of nx (λ). Represents a rate. In the refractive index ellipsoid formed by the optical film, nz (λ) represents a refractive index in a direction perpendicular to the film plane with respect to light having a wavelength λ (nm). ] The first retardation layer is
In the refractive index ellipsoid formed by the first retardation layer, in the wavelength λ = 400 to 700 nm range,
nx1 (λ)> ny1 (λ) ≈nz1 (λ)
[Wherein, nx1 (λ) represents a main refractive index in a direction parallel to the film plane with respect to light of wavelength λ (nm) in the refractive index ellipsoid formed by the first retardation layer. ny1 (λ) is a refractive index ellipsoid formed by the first retardation layer and is parallel to the film plane and has a wavelength λ (nm) in a direction perpendicular to the direction of nx1 (λ). Represents the refractive index of light. In the refractive index ellipsoid formed by the first retardation layer, nz1 (λ) represents a refractive index in a direction perpendicular to the film plane with respect to light having a wavelength λ (nm). ]
Have the relationship
The optical film of Claim 1 satisfy | filling the relationship of following formula (3) and (4).
Re1 (450) / Re1 (550) ≦ 1.00 (3)
1.00 ≦ Re1 (650) / Re1 (550) (4)
[Where Re1 (450) is the in-plane retardation value of the first retardation layer for light of wavelength λ = 450 nm, and Re1 (550) is the in-plane position of the first retardation layer for light of wavelength λ = 550 nm. The phase difference value Re1 (650) indicates the in-plane retardation value of the first retardation layer with respect to the light with the wavelength λ = 650 nm, and the in-plane retardation value Re1 (λ with respect to the light with the wavelength λnm. )
Re1 (λ) = (nx1 (λ) −ny1 (λ)) × d1
It is represented by Here, d1 represents the thickness of the first retardation layer. ] The second retardation layer is
In the refractive index ellipsoid formed by the second retardation layer, in the wavelength λ = 400 to 700 nm range,
nz2 (λ)> nx2 (λ) ≈ny2 (λ)
[Wherein, nz2 (λ) represents the refractive index in the direction perpendicular to the film plane with respect to light of wavelength λ (nm) in the refractive index ellipsoid formed by the second retardation layer. In the refractive index ellipsoid formed by the second retardation layer, nx2 (λ) represents the maximum refractive index in a direction parallel to the film plane with respect to light having a wavelength λ (nm). ny2 (λ) is a refractive index ellipsoid formed by the second retardation layer, and is parallel to the film plane and with respect to light having a wavelength λ (nm) in a direction orthogonal to the nx2 direction. Refractive index. However, when nx2 (λ) = ny2 (λ), nx2 (λ) represents a refractive index in an arbitrary direction parallel to the film plane. ]
Have the relationship
The optical film of Claim 1 or Claim 2 which satisfy | fills the relationship of following formula (5) and (6).
Rth2 (450) / Rth2 (550) ≦ 1.00 (5)
1.00 ≦ Rth2 (650) / Rth2 (550) (6)
[Where Rth2 (450) is the thickness direction retardation value for light of wavelength λ = 450 nm, and Rth2 (550) is the thickness direction retardation value of the second retardation layer for light of wavelength λ = 550 nm. , Rth2 (650) represents a retardation value in the thickness direction of the second retardation layer with respect to light having a wavelength of 650 nm, and a retardation value Rth2 in the thickness direction of the second retardation layer with respect to light having a wavelength λ (nm). (Λ) is
Rth2 (λ) = [(nx2 (λ) + ny2 (λ)) / 2−nz2 (λ)] × d2
It is represented by Here, in the refractive index ellipsoid formed by the second retardation layer, nz2 (λ) represents the main 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 on the film plane at the wavelength λ (nm). d2 represents the thickness of the second retardation layer. ] The optical film according to claim 1, wherein the first retardation layer further satisfies the relationship of the following formula (7).
120 nm ≦ Re1 (550) ≦ 170 nm (7)
[In the formula, Re1 (550) represents an in-plane retardation value of the first retardation layer with respect to light having a wavelength λ = 550 nm. ] The optical film according to any one of claims 1 to 4, wherein the second retardation layer further has optical properties represented by the formula (9).
−100 nm ≦ Rth2 (550) ≦ −50 nm (8)
[Wherein Rth2 (550) represents a retardation value in the thickness direction of the second retardation layer with respect to light having a wavelength λ = 550 nm. ] The optical film according to claim 1, wherein the second retardation layer is a film composed of a coating layer formed by polymerizing a polymerizable liquid crystal in an aligned state. The optical film according to claim 1, wherein the first retardation layer is a film comprising a coating layer formed by polymerizing a polymerizable liquid crystal in an aligned state. The optical film according to claim 1, wherein the second retardation layer is 5 μm or less. The optical film according to claim 1, wherein the first retardation layer is 5 μm or less. The optical film according to claim 1, wherein the first retardation layer and the second retardation layer are coating layers formed by mainly polymerizing the same polymerizable liquid crystal compound. An elliptically polarizing plate with an optical compensation function, comprising the optical film according to claim 1 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 first retardation layer The elliptically polarizing plate with an optical compensation function according to claim 11, wherein the slow axis of the second retardation layer and the slow axis of the second retardation layer are perpendicular to the film surface. The ellipse with an optical compensation function according to claim 11 or 12, wherein the polarizing plate, the adhesive layer, the first retardation layer, the adhesive layer, and the second retardation layer are formed in this order. Polarizer. The ellipse with optical compensation function according to claim 11 or 12, wherein the polarizing plate, the adhesive layer, the second retardation layer, the adhesive layer, and the first retardation layer are formed in this order. Polarizer. An organic EL display device comprising the elliptically polarizing plate with an optical compensation function according to claim 12. The manufacturing method of the elliptically polarizing plate with an optical compensation function in any one of Claims 11-14 with an optical compensation function including all the following processes.
(Step 1-A) After applying a polymerizable liquid crystal compound on a substrate on which a horizontal alignment film is formed, a step of forming a retardation layer by polymerizing in a horizontally aligned state;
(Step 1-B) A step of forming a second retardation layer by applying a polymerizable liquid crystal compound on a substrate on which a vertical alignment film is formed, and then polymerizing 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 via an adhesive and laminating them on the polarizing plate