KR20230115958A - Optical film and method of manufacturing the same - Google Patents

Abstract

(Problem) To provide a novel optical film in which light refractive index is controlled in a three-dimensional direction over the entire visible light range and in all orientations to be viewed, and a manufacturing method thereof.
(Solution Means) An optical film having a first retardation layer and a second retardation layer, and satisfying the relationships of the following formulas (1) and (2).
0.4 ≤ Nz (450) ≤ 0.6 (1)
0.4 ≤ Nz (550) ≤ 0.6 (2)
[Wherein, Nz (450) represents the Nz coefficient of the optical film for light with a wavelength of λ = 450 nm, and Nz (550) represents the Nz coefficient of the optical film for light with a wavelength of λ = 550 nm, respectively.]

Description

Optical film and its manufacturing method {OPTICAL FILM AND METHOD OF MANUFACTURING THE SAME}

The present invention relates to an optical film and a manufacturing method thereof.

BACKGROUND OF THE INVENTION Optical films such as polarizing plates and retardation plates are used in flat panel displays (FPDs). Uniform phase conversion is required for the retardation plate over the entire visible light range. For example, in Patent Document 1, a reverse wavelength dispersive retardation film oriented in the horizontal direction, and in Patent Document 2, a reverse wavelength dispersive retardation film oriented in the vertical direction is disclosed. A film is disclosed.

Japanese Published Patent Publication No. 2010-537955 Japanese Unexamined Patent Publication No. 2015-57646

In recent years, with the evolution of flat panel displays, a clear black display is required when viewed from any orientation. As a result, the problem that wavelength dispersion control alone in the horizontal or vertical direction is insufficient has become clear.

The present invention includes the following inventions.

[1] An optical film having a first retardation layer and a second retardation layer, and satisfying the relationships of the following formulas (1) and (2).

0.4 ≤ Nz(450) ≤ 0.6 (One)

0.4 ≤ Nz(550) ≤ 0.6 (2)

[Wherein, Nz (450) denotes the Nz coefficient of the optical film for light of wavelength λ = 450 nm, Nz (550) denotes the Nz coefficient of the optical film for light of wavelength λ = 550 nm, respectively, and the wavelength λ The Nz coefficient Nz (λ) of the optical film for light of (nm) is

Nz (λ) = (nx (λ) - nz (λ)) / (nx (λ) - ny (λ))

indicated by nx (λ) represents the principal refractive index of light having a wavelength of λ (nm) in a direction parallel to the film plane in the refractive index ellipsoid formed by the optical film. ny (λ) represents the refractive index of the refractive index ellipsoid formed by the optical film in a direction parallel to the film plane for light having a wavelength of λ (nm) and orthogonal to the nx (λ) direction.

nz (λ) represents the refractive index in the direction perpendicular to the film plane for light of wavelength λ (nm) in the refractive index ellipsoid formed by the optical film.]

[2] The first retardation layer,

In the refractive index ellipsoid formed by the first retardation layer, in the range of wavelength λ = 400 to 700 nm, nx1 (λ) > ny1 (λ) ≒ nz1 (λ)

[In the formula, nx1 (λ) represents the principal refractive index of light having a wavelength of λ (nm) in a direction parallel to the film plane in the refractive index ellipsoid formed by the first retardation layer. ny1 (λ) represents the refractive index for light of wavelength λ (nm) in a direction parallel to the film plane and orthogonal to the direction of nx1 (λ) in the refractive index ellipsoid formed by the first retardation layer . In the refractive index ellipsoid formed by the first retardation layer, nz1 (λ) represents the refractive index of light of wavelength λ (nm) in a direction perpendicular to the film plane.]

have a relationship with

The optical film according to [1] above, which satisfies the relationships of the following formulas (3) and (4).

Re1(450)/Re1(550) ≤ 1.00 (3)

1.00 ≤ Re1 (650)/Re1 (550) (4)

[Wherein, Re1 (450) is the in-plane retardation value of the first retardation layer for light with a wavelength of λ = 450 nm, Re1 (550) is the in-plane retardation value of the first retardation layer for light with a wavelength of λ = 550 nm Re1 (650) represents the in-plane retardation value of the first retardation layer for light of wavelength λ = 650 nm, respectively, and the in-plane retardation value Re1 (λ) of the first retardation layer for light of wavelength λ nm is,

Re1 (λ) = (nx1 (λ) - ny1 (λ)) × d1

represented by Here, d1 represents the thickness of the first retardation layer.]

[3] The second retardation layer,

In the refractive index ellipsoid formed by the second retardation layer, in the range of wavelength λ = 400 to 700 nm, nz2 (λ) > nx2 (λ) ≈ ny2 (λ)

[In the formula, nz2 (λ) represents the refractive index in the direction perpendicular to the film plane for light having a wavelength of λ (nm) 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 for light having a wavelength of λ (nm) in the refractive index ellipsoid formed by the second retardation layer. ny2(λ) represents the refractive index for light having a wavelength λ (nm) in a direction parallel to the film plane and orthogonal to the direction of nx2 in the refractive index ellipsoid formed by the second retardation layer. However, when nx2 (λ) = ny2 (λ), nx2 (λ) represents the refractive index in an arbitrary direction parallel to the film plane.]

have a relationship with

The optical film according to the above [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)

[Wherein, Rth2 (450) is the retardation value in the thickness direction for light with a wavelength of λ = 450 nm, and Rth2 (550) is the retardation value in the thickness direction of the second retardation layer for light with a wavelength of λ = 550 nm. , Rth2 (650) represent the retardation value in the thickness direction of the second retardation layer for light with a wavelength of 650 nm, respectively, and the retardation value in the thickness direction of the second retardation layer for light with a wavelength of λ (nm) Rth2 (λ) Is,

Rth2 (λ) = [(nx2 (λ) + ny2 (λ))/2 - nz2 (λ)] × d2

represented by Here, in the refractive index ellipsoid formed by the second retardation layer, nz2 (λ) represents the principal refractive index in the direction perpendicular to the film plane at the wavelength λ (nm), ((nx2 (λ) + ny2 (λ) )/2) represents the average refractive index in 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 formula (7) below.

120 nm ≤ Re1 (550) ≤ 170 nm (7)

[Wherein, Re1 (550) represents the in-plane retardation value of the first retardation layer for light having a wavelength of λ = 550 nm]

[5] The optical film according to any one of [1] to [4], wherein the second retardation layer further has optical properties represented by formula (8).

-100 nm ≤ Rth2 (550) ≤ -50 nm (8)

[Wherein, Rth2 (550) represents the retardation value in the thickness direction of the second retardation layer for light having a wavelength of λ = 550 nm]

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

[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 polymerizable liquid crystals in an aligned state.

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

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

[10] The optical film according to any one of [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.

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

[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 ° within the film plane, and 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 ° The elliptically polarizing plate provided with the optical compensation function described in [11] above, wherein the axis and the slow axis of the second retardation layer are orthogonal to the film plane in the vertical direction.

[13] An elliptically polarizing plate provided with the optical compensation function described in [11] or [12] above, which is an optical laminate comprising a polarizing plate, a point adhesive layer, a first retardation layer, a point adhesion layer, and a second retardation layer formed in this order.

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

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

A method for producing an elliptically polarizing plate provided with an optical compensation function according to any one of [11] to [14] above, including all of the following steps.

(Step 1-A) A step of forming a first retardation layer by applying a polymerizable liquid crystal compound on a substrate on which a horizontal alignment film is formed and then polymerizing the compound 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 it in a vertically aligned state;

(Step 2) A step of transferring the liquid crystal polymer of the first retardation layer and the liquid crystal polymer of the second retardation layer from the base material through an adhesive agent and laminating them on a polarizing plate.

According to the present invention, a novel optical film whose light refractive index is controlled in a three-dimensional direction over the entire visible light range and in all orientations to be viewed and a manufacturing method thereof are provided. Also provided are liquid crystal display devices and organic EL display devices enabling clear display by using this optical film.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described in detail. In addition, the scope of the present invention is not limited to the embodiment described here, and various changes can be made within a range not impairing the gist of the present invention.

The optical film of the present invention consists of a first retardation layer and a second retardation layer. The first retardation layer and the second retardation layer may be formed by a method of stretching or shrinking a polymer film, but from the viewpoint of thinning, in a state in which a polymerizable liquid crystal (hereinafter also referred to as a polymerizable liquid crystal compound) is coated and aligned. It is preferable that it is a film consisting of a coating layer formed by polymerization.

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 “composition for forming a retardation layer”) on a transparent substrate to form a layer, followed by heating and cooling treatment. It is preferable to use a polymer in the alignment state of the polymerizable liquid crystal compound in terms of thinning and wavelength dispersion characteristics can be designed arbitrarily. Moreover, so that it may mention later, the composition for retardation layer formation may further contain a solvent, a photoinitiator, a photosensitizer, a polymerization inhibitor, a leveling agent, and an adhesion improver.

The first retardation layer is preferably a liquid crystal cured film cured in a state in which the polymerizable liquid crystal compound is oriented in a horizontal direction with respect to the substrate surface, and the second retardation layer is a liquid crystal cured film in which the polymerizable liquid crystal compound is oriented in a vertical direction with respect to the substrate surface. It is preferable that it is a liquid crystal cured film hardened|cured in the state.

In the first retardation layer, Re1 (550), which 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). In addition, the first retardation layer has Re1 (450), which is an in-plane retardation value for light with a wavelength of 450 nm, Re1 (550), which is an in-plane retardation value for light with a wavelength of 550 nm, and an in-plane retardation value for light with a wavelength of 650 nm It is also preferable that the phosphorus Re1 (650) satisfies the optical properties represented by formulas (3) and (4). The first retardation layer more preferably satisfies the optical properties 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) for 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)

(Wherein, Re1 (450) is the in-plane retardation value for light with a wavelength of 450 nm of the first retardation layer, Re1 (550) is the in-plane retardation value for light with a wavelength of 550 nm of the first retardation layer, Re1 ( 650) represent in-plane retardation values for light with a wavelength of 650 nm of the first retardation layer, respectively)

When the in-plane retardation value Re1 (550) of the first retardation layer exceeds the range of Equation (7), the optical film of the present invention is combined with a polarizing plate to form an elliptically polarizing plate with an optical compensation function described later. There may be a problem that the frontal color becomes reddish or bluish when bonded. 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 increases. It is preferably 0.75 or more and 0.92 or less, more preferably 0.77 or more and 0.87 or less, and still more preferably 0.79 or more and 0.85 or less.

The in-plane retardation value of the first retardation layer can be adjusted by the thickness of the retardation layer. Since the in-plane retardation value is determined by the following formula (A), in order to obtain the desired in-plane retardation value (Re1 (λ): in-plane retardation value of the first retardation layer at the wavelength λ (nm)), the three-dimensional refractive index and the film Just adjust the thickness d1. The thickness of the retardation layer is preferably from 0.5 μm to 5 μm, and more preferably from 1 μm to 3 μm. The thickness of the retardation layer can be measured by an interference film thickness gage, a laser microscope, or a stylus-type film thickness gage. In addition, a three-dimensional refractive index depends on the molecular structure and orientation state of a polymeric liquid crystal compound mentioned later.

Re1 (λ) = (nx1 (λ) - ny1 (λ)) × d1 (A)

(In the formula, in the refractive index ellipsoid formed by the first retardation layer, nx1 (λ) > ny1 (λ) ≒ nz1 (λ) has a relationship, nx1 (λ) is a film plane for light with a wavelength of λ (nm) In the refractive index ellipsoid formed by the first retardation layer for light of wavelength λ (nm), ny1 (λ) is parallel to the film plane, and its nx1 (λ) Represents the refractive index in a direction orthogonal to the direction d1 represents the thickness of the first retardation layer. Also, "ny1 (λ) ≈ nz1 (λ)" means that ny1 (λ) and nz1 (λ) are substantially It means the same thing, and indicates, for example, that the numerical difference is within 0.01.)

In the second retardation layer, Rth2 (λ), which is a retardation value in the thickness direction for light having a wavelength of λ nm, preferably satisfies the optical characteristics represented by the following formula (8). Moreover, it is also preferable to satisfy the optical characteristics represented by the following formula (5) and formula (6). The second retardation layer more preferably satisfies the optical properties 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 the retardation value in the thickness direction for light having a wavelength of 550 nm)

Rth2(450)/Rth2(550) ≤ 1.0 … (5)

1.00 ≤ Rth2 (650) / Rth2 (550) … (6)

(Wherein, Rth2 (450) is the retardation value in the thickness direction for light with a wavelength of 450 nm, Rth2 (550) has the same meaning as above, Rth2 (650) is the phase difference in the thickness direction for light with a wavelength of 650 nm value respectively)

When the retardation value Rth2 (550) in the thickness direction of the second retardation layer exceeds the range of formula (8), the optical film of the present invention is combined with a polarizing plate to form an elliptically polarizing plate with an optical compensation function described later. There may be a problem that the color of all sides becomes reddish or bluish when bonded to a mirror. A more preferred range of the retardation value in the thickness direction is -95 nm ≤ Rth2 (550) ≤ -55 nm, and a more preferred 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 increases. It is preferably 0.75 or more and 0.92 or less, more preferably 0.77 or more and 0.87 or less, and still more preferably 0.79 or more and 0.85 or less.

The phase difference value in the thickness direction of the second phase difference layer can be adjusted by the thickness of the phase difference layer. Since the retardation value in the thickness direction is determined by the following formula (B), in order to obtain a desired retardation value in the thickness direction (Rth2 (λ): retardation value in the thickness direction of the second retardation layer at wavelength λ (nm)) , the three-dimensional refractive index and the film thickness d2 may be adjusted. The thickness of the retardation layer is preferably from 0.2 μm to 5 μm, and more preferably from 0.5 μm to 2 μm. The thickness of the retardation layer can be measured by an interference film thickness gage, a laser microscope, or a stylus-type film thickness gage. In addition, a three-dimensional refractive index depends on the molecular structure and orientation of the polymeric liquid crystal compound mentioned later.

Rth2 (λ) = [(nx2 (λ) + ny2 (λ))/2 - nz2 (λ)] × d2 (B)

(In the formula, nz2 (λ) > nx2 (λ) ≒ ny2 (λ) in the refractive index ellipsoid formed by the second phase difference layer, in the formula, nz2 (λ) is the refractive index formed by the second phase difference layer In the ellipsoid, represents the refractive index in the direction perpendicular to the film plane for light of wavelength λ (nm) nx2 (λ) is the refractive index ellipsoid formed by the second retardation layer, for light of wavelength λ (nm) represents the maximum refractive index in a direction parallel to the film plane for ny2 (λ) is a wavelength in a direction parallel to the film plane and orthogonal to the nx2 direction in the refractive index ellipsoid formed by the second retardation layer Represents the refractive index for light of λ (nm) However, when nx2 (λ) = ny2 (λ), nx2 (λ) represents the refractive index in an arbitrary direction parallel to the film plane, where d2 represents the thickness of the second retardation layer, and "nx2 (λ) ≈ ny2 (λ)" means that nx2 (λ) and ny2 (λ) are substantially the same, for example, the numerical difference is within 0.01 indicates that.)

The optical film of the present invention has a first retardation layer and a second retardation layer, and satisfies the relationships of the following formulas (1) and (2).

0.40 ≤ Nz(450) ≤ 0.60 (One)

0.40 ≤ Nz(550) ≤ 0.60 (2)

(Wherein, Nz (λ) is the Nz coefficient representing the relationship of the three-dimensional refractive index for light of wavelength λ (nm), Nz (λ) = (nx (λ) - nz (λ)) / (nx (λ) ) -ny (λ)) nx (λ) represents the principal refractive index of light of wavelength λ (nm) in a direction parallel to the film plane in the refractive index ellipsoid formed by the optical film. (λ) represents the refractive index of the refractive index ellipsoid formed by the optical film in a direction parallel to the film plane for light of wavelength λ (nm) and orthogonal to the direction of nx (λ). (λ) represents the refractive index in the direction perpendicular to the film plane for light of wavelength λ (nm) in the refractive index ellipsoid formed by the optical film.)

In short, 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 equations (1) and (2), so that display mounting It is possible to impart display characteristics with excellent color upon viewing. 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 a wavelength of λ = 450 nm, and Nz (550) represents an Nz coefficient at a wavelength of λ = 550 nm, respectively.

The Nz coefficient (Nz coefficient: Nz (λ)) representing the relationship among nx (λ), ny (λ), and nz (λ) at each wavelength λ (nm) of the optical film is calculated by the following formula.

Nz (λ) = (nx (λ) - nz (λ)) / (nx (λ) - ny (λ))

Moreover, when calculating the Nz coefficient of the optical film, when the front retardation value of the 1st retardation layer and the 2nd retardation layer and the retardation value of thickness direction are known, it is computable also by the following formula (C).

Nz (λ) = (Rth1 (λ) + Rth2 (λ))/(Re1 (λ) + Re2 (λ)) + 0.5 (C)

(Wherein, Re1 (λ) is the front retardation value of the first retardation layer at wavelength λ (nm), Re2 (λ) is the front retardation value of the second retardation layer at wavelength λ (nm), Rth1 ( λ) is the retardation value in the thickness direction of the first retardation layer at the wavelength λ (nm), and Rth2 (λ) is the retardation value in the thickness direction of the second retardation layer at the wavelength λ (nm))

[Polymerizable liquid crystal]

A polymerizable liquid crystal compound is a liquid crystal compound having a polymerizable functional group, particularly a photopolymerizable functional group.

A photopolymerizable functional group refers to a group that can be involved 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, a vinyloxy group, a 1-chlorovinyl group, an isopropenyl group, a 4-vinylphenyl group, an acryloyloxy group, a methacryloyloxy group, an oxiranyl group, and an oxetanyl group. can Especially, an acryloyloxy group, a methacryloyloxy group, a vinyloxy group, an oxiranyl group, and an oxetanyl group are preferable, and an acryloyloxy group is more preferable. The liquid crystal may be either a thermotropic liquid crystal or a lyotropic liquid crystal, but a thermotropic liquid crystal is preferable in terms of precise film thickness control. Moreover, as a paraorder structure in a thermotropic liquid crystal, a nematic liquid crystal or a smectic liquid crystal may be sufficient.

In this invention, as a polymeric liquid crystal compound, the structure of following formula (I) is especially preferable at the point which expresses the above-mentioned reverse wavelength dispersion property.

[Formula 1]

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 cyclic structure, and means that the number of π electrons in the cyclic structure is [4n + 2] according to the Hickel's law. Here, n represents an integer. When a ring structure is formed by containing a hetero atom such as -N= or -S-, the Huckel's law is satisfied by including a pair of non-covalent bonding electrons on these hetero atoms, and aromaticity is also included. It is preferable that at least 1 or more of a nitrogen atom, an oxygen atom, and a sulfur atom contain in this divalent aromatic group.

G ¹ and G ² each independently represent a divalent aromatic group or a divalent alicyclic hydrocarbon group. Here, the hydrogen atom contained in the divalent aromatic group or the divalent alicyclic hydrocarbon group is a halogen atom, an alkyl group of 1 to 4 carbon atoms, a fluoroalkyl group of 1 to 4 carbon atoms, an alkoxy group of 1 to 4 carbon atoms, a cyano group, or It may be substituted with a nitro group, and the carbon atom constituting the divalent aromatic group or the divalent alicyclic hydrocarbon group may be substituted with an oxygen atom, a sulfur atom or 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 + l. Here, when 2 ≤ k + l, B ¹ and B ² , G ¹ and G ² may be the same as or different from each other.

E ¹ and E ² each independently represent an alkanediyl group having 1 to 17 carbon atoms, wherein the hydrogen atom contained in the alkanediyl group may be substituted with a halogen atom, and —CH ₂ contained in the alkanediyl group - 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, a halogen atom, and A 1,4-cyclohexanediyl group optionally substituted with at least one substituent selected from the group consisting of an alkyl group having 1 to 4 carbon atoms, more preferably a 1,4-phenylenediyl group substituted with a methyl group, an unsubstituted 1,4-phenylenediyl group or unsubstituted 1,4-trans-cyclohexanediyl group, particularly preferably unsubstituted 1,4-phenylenediyl group or unsubstituted 1,4-trans-cyclohexane group. It is a hexanediyl group.

In addition, it is preferable that at least one of the plurality of G ¹ and G ² is a divalent alicyclic hydrocarbon group, and at least one of G ¹ and G ² bonded to L ¹ or L ² is a divalent alicyclic hydrocarbon It is more preferable to originate.

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 of 1 to 4 carbon atoms, and R ^c and R ^d represent an alkyl group of 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 - am. Here, R ^a2-1 , R ^a4-1 , and R ^a6-1 each independently represent either a single bond, -CH ₂ -, or -CH ₂ CH ₂ -. L ¹ and L ² are each independently, more preferably a single bond, -O-, -CH ₂ CH ₂ -, -COO-, -COOCH ₂ CH ₂ -, or -OCO-.

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

From the viewpoint of the expression of reverse wavelength dispersion, k and l are preferably in the range of 2 ≤ k + l ≤ 6, preferably k + l = 4, and more preferably k = 2 and l = 2.

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

Examples of the polymerizable group represented by P ¹ or P ² include an epoxy group, a vinyl group, a vinyloxy group, a 1-chlorovinyl group, an isopropenyl group, a 4-vinylphenyl group, an acryloyloxy group, a methacryloyloxy group, and an oxiranyl group. , And an oxetanyl group, etc. are mentioned.

Especially, an acryloyloxy group, a methacryloyloxy group, a vinyloxy group, an oxiranyl group, and an oxetanyl group are preferable, and an acryloyloxy group is more preferable.

Ar preferably has at least one selected from an aromatic hydrocarbon ring which may have a substituent, an aromatic heterocyclic ring which may have a substituent, and an electron-withdrawing group. As the said aromatic hydrocarbon ring, a benzene ring, a naphthalene ring, an anthracene ring etc. are mentioned, for example, A benzene ring and a naphthalene ring are preferable. Examples of the aromatic heterocycle include a furan ring, a benzofuran ring, a pyrrole ring, an indole ring, a thiophene ring, a benzothiophene ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a triazole ring, a triazine ring, and a pyrroline ring. , imidazole ring, pyrazole ring, thiazole ring, benzothiazole ring, thienothiazole ring, oxazole ring, benzoxazole ring, and phenanthroline ring. Especially, what has a thiazole ring, a benzothiazole ring, or a benzofuran ring is preferable, and what has a benzothiazole group is more preferable. Further, when Ar contains a nitrogen atom, the nitrogen atom preferably has π electrons.

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

As an aromatic group represented by Ar, the following groups are mentioned, for example.

[Formula 2]

In the formulas (Ar-1) to (Ar-22), * indicates a linking portion, and Z ⁰ , Z ¹ and Z ² are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, or cyanide. No group, nitro group, C1-C12 alkylsulfinyl group, C1-C12 alkylsulfonyl group, carboxyl group, C1-C12 fluoroalkyl group, C1-C6 alkoxy group, C1-C12 alkylthio group , N-alkylamino group of 1 to 12 carbon atoms, N,N-dialkylamino group of 2 to 12 carbon atoms, N-alkylsulfamoyl group of 1 to 12 carbon atoms or N,N-dialkylsulfamoyl group of 2 to 12 carbon atoms indicates

Q ¹ and Q ² each independently represent -CR ^2' R ^3' -, -S-, -NH-, -NR ^2' -, -CO- or -O-, and R ^2' and R ^{3 '} respectively 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 represent an optionally substituted aromatic hydrocarbon group or aromatic heterocyclic group.

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

Examples of the aromatic hydrocarbon group for Y ¹ , Y ² and Y ³ include aromatic hydrocarbon groups having 6 to 20 carbon atoms such as a phenyl group, a naphthyl group, anthryl group, a phenanthryl group and a biphenyl group, and a phenyl group and a naphthyl group preferred, and a phenyl group is more preferred. As the aromatic heterocyclic group, a furyl group, a pyrrolyl group, a thienyl group, a pyridinyl group, a thiazolyl group, a nitrogen atom such as a benzothiazolyl group, an oxygen atom, and a sulfur atom containing at least one hetero atom such as 4 to 4 carbon atoms An aromatic heterocyclic group of 20 is exemplified, 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 a polycyclic aromatic heterocyclic group. The polycyclic aromatic hydrocarbon group refers to a condensed polycyclic aromatic hydrocarbon group or a group derived from an aromatic ring group. The polycyclic aromatic heterocyclic group refers to a condensed polycyclic aromatic heterocyclic group or a group derived from an aromatic ring group.

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, and Z ⁰ is a hydrogen atom , an alkyl group of 1 to 12 carbon atoms, or a cyano group is more preferable, 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 and Q ² are preferably -NH-, -S-, -NR ^2' -, or -O-, and R ^2' is preferably a hydrogen atom. Especially, -S-, -O-, and -NH- are especially preferable.

Among formulas (Ar-1) to (Ar-22), formulas (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 and Z ⁰ to which Y 1 bonds. Examples of the aromatic heterocyclic group include those described above as the aromatic heterocyclic ring that Ar may have, and examples thereof include a pyrrole ring, an imidazole ring, a pyrroline ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, an indole ring, A quinoline ring, an isoquinoline ring, a purine ring, a pyrrolidine ring, etc. are mentioned. This aromatic heterocyclic group may have a substituent. Y ¹ together with the nitrogen atom and Z ⁰ to which Y 1 is bonded may be the above-described optionally substituted polycyclic aromatic hydrocarbon group or polycyclic aromatic heterocyclic group. For example, a benzofuran ring, a benzothiazole ring, a benzoxazole ring, etc. are mentioned.

The content of the total polymerizable liquid crystal compound in 100 parts by mass of the solid content of the composition for forming a retardation layer is usually 70 parts by mass to 99.5 parts by mass, preferably 80 parts by mass to 99 parts by mass, more preferably It is 80 mass parts - 94 mass parts, It is 80 mass parts - 90 mass parts more preferably. When the content of the sum is within the above range, the orientation of the polymerizable liquid crystal compound tends to increase in the retardation layer obtained. Here, the solid content refers to the total amount of components 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 inactive 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; ester solvents such as ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, γ-butyrolactone, propylene glycol methyl ether acetate, and ethyl lactate; Ketone solvents, such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, 2-heptanone, and methyl isobutyl ketone; aliphatic hydrocarbon solvents such as pentane, hexane and heptane; aromatic hydrocarbon solvents such as toluene and xylene; nitrile solvents such as acetonitrile; ether solvents such as tetrahydrofuran and dimethoxyethane; chlorine-containing solvents such as chloroform and chlorobenzene; and amide solvents such as dimethylacetamide, dimethylformamide, N-methyl-2-pyrrolidone, and 1,3-dimethyl-2-imidazolidinone. These solvents may be used alone or in combination of two or more. Among them, alcohol solvents, ester solvents, ketone solvents, chlorine-containing solvents, amide solvents and aromatic hydrocarbon solvents are preferred.

The content of the solvent in 100 parts by mass of the composition is preferably from 50 parts by mass to 98 parts by mass, and more preferably from 70 parts by mass to 95 parts by mass. Therefore, the solid content in 100 parts by mass of the composition is preferably from 2 parts by mass to 50 parts by mass. If the solid content of the composition is 50 parts by mass or less, since the viscosity of the composition is low, the thickness of the retardation layer becomes substantially uniform, and unevenness in the retardation layer tends to be less likely to occur. The solid content can be appropriately determined in consideration of the thickness of the retardation layer to be manufactured.

<Polymerization initiator>

A polymerization initiator is a compound capable of initiating a polymerization reaction of a polymerizable liquid crystal or the like by generating a reactive active species by contribution of heat or light. Active species, such as a radical or a cation or an anion, are mentioned as a reactive active species. Among them, a photopolymerization initiator that generates radicals upon light irradiation is preferable from the viewpoint of easy reaction control.

As a photoinitiator, a benzoin compound, a benzophenone compound, a benzyl ketal compound, (alpha)-hydroxy ketone compound, (alpha)-amino ketone compound, a triazine compound, an iodonium salt, and a sulfonium salt are mentioned, for example. 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, manufactured by BASF Japan Co., Ltd.), Shakeol BZ, Shakeol Z, Shakeol BEE (above, manufactured by Seiko Chemical Co., Ltd.), Kayacure BP100 ( Nippon Explosive Co., Ltd.), Kayacure UVI-6992 (manufactured by Dawoo), Adeka Optomer SP-152, Adeka Optomer SP-170, Adeka Optomer N-1717, Adeka Optomer N-1919, Adeka Optomer Deca Acruze NCI-831, Adeka Acruz NCI-930 (above, manufactured by ADEKA Co., Ltd.), TAZ-A, TAZ-PP (above, manufactured by Nippon Sibel Hegna Co., Ltd.) and TAZ-104 (manufactured by Sanwa Chemical Co., Ltd.) can be heard

In the composition for forming a retardation layer, the photopolymerization initiator to be contained is at least one type, and preferably one type or two types.

Since the photopolymerization initiator can fully utilize the energy emitted from the light source and has excellent productivity, the maximum absorption wavelength is preferably 300 nm to 400 nm, more preferably 300 nm to 380 nm, and among them, α- An acetophenone-based polymerization initiator and an oxime-based photopolymerization initiator are preferred.

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

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

The amount of the photopolymerization initiator added is usually 0.1 part by mass to 30 parts by mass, preferably 1 part by mass to 20 parts by mass, more preferably 1 part by mass to 15 parts by mass, based on 100 parts by mass of the polymerizable liquid crystal compound. It is wealth. Within the above range, the reaction of the polymerizable group sufficiently proceeds, and the alignment of the polymerizable liquid crystal compound is not easily disturbed.

By blending the polymerization inhibitor, the polymerization reaction of the polymerizable liquid crystal compound can be controlled. Examples of the polymerization inhibitor include hydroquinones having substituents such as hydroquinone and alkyl ether; catechols having substituents such as alkyl ethers such as butyl catechol; radical scavengers such as pyrogallols and 2,2,6,6-tetramethyl-1-piperidinyloxy radical; Thiophenols; β-naphthylamines and β-naphthols are exemplified. The content of the polymerization inhibitor is usually 0.01 to 10 parts by mass, preferably 0.1 to 100 parts by mass of the polymerizable liquid crystal compound, in order to polymerize the polymerizable liquid crystal compound without disturbing the orientation of the polymerizable liquid crystal compound. to 5 parts by mass, more preferably 0.1 to 3 parts by mass.

Moreover, the photoinitiator can be highly sensitized by using a sensitizer. Examples of the photosensitizer include xanthones such as xanthone and thioxanthone; anthracenes having substituents such as anthracene and alkyl ether; phenothiazine; Rubren can be mentioned. The content of the photosensitizer is usually 0.01 to 10 parts by mass, preferably 0.05 to 5 parts by mass, more preferably 0.1 to 3 parts by mass, based on 100 parts by mass of the polymerizable liquid crystal compound.

[Leveling agent]

The leveling agent is an additive having a function of adjusting the flowability of the composition and making the film obtained by applying the composition more flat, for example, leveling of silicone type such as silane coupling agent, polyacrylate type and perfluoroalkyl type can be heard Specifically, DC3PA, SH7PA, DC11PA, SH28PA, SH29PA, SH30PA, ST80PA, ST86PA, SH8400, SH8700, FZ2123 (above, all 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-802, KBM-802, KBM -803, KBE-846, KBE-9007 (above, all manufactured by Shin-Etsu Chemical Industry Co., Ltd.), TSF400, TSF401, TSF410, TSF4300, TSF4440, TSF4445, TSF-4446, TSF4452, TSF4460 (above, all Momentive Performance Materials Manufactured by Sumitomo 3M Co., Ltd.), Flurinert (registered trademark) FC-72, FC-40, FC-43, FC-3283 (both above, all manufactured by Sumitomo 3M Co., Ltd.), Megafac ( 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 (above, all manufactured by DIC Co., Ltd.), Ftop (trade name) EF301, same EF303, same EF351, same EF352 (above, all manufactured by Mitsubishi Material Electron Chemical Co., Ltd.) , Suffron (registered trademark) S-381, S-382, S-383, S-393, SC-101, SC-105, KH-40, SA-100 (above, all AGC Semi Chemical Co., Ltd.), trade names E1830, E5844 (manufactured by Daikin Fine Chemical Laboratory, Inc.), BM-1000, BM-1100, BYK-352, BYK-353 and BYK-361N (all trade names: BM Chemie) production), etc.

The content of the leveling agent in the composition for forming a retardation layer is preferably from 0.01 part by mass to 5 parts by mass, more preferably from 0.05 part by mass to 3 parts by mass with respect to 100 parts by mass of the polymerizable liquid crystal compound. When the content of the leveling agent is within the above range, it is easy to horizontally align the polymerizable liquid crystal compound, and the obtained retardation layer tends to be smoother, which is preferable. The composition for retardation layer formation may contain two or more types of leveling agents.

[write]

As the base material, a glass base material and a film base material are exemplified, a film base material is preferable from the viewpoint of workability, and a long roll-shaped film is more preferable from the viewpoint of being able to be continuously produced. Examples of the resin constituting the film substrate include polyolefins such as polyethylene, polypropylene, and norbornene polymers; Cyclic olefin resin; polyvinyl alcohol; polyethylene terephthalate; Polymethacrylic acid ester; polyacrylic acid ester; cellulose esters such as triacetyl cellulose, diacetyl cellulose, and cellulose acetate propionate; polyethylene naphthalate; polycarbonate; polysulfone; polyethersulfone; polyether ketone; polyphenylene sulfide and polyphenylene oxide; Plastics, such as these, are mentioned.

Examples of commercially available cellulose ester substrates include "Fujitac Film" (manufactured by Fuji Photo Film Co., Ltd.); "KC8UX2M", "KC8UY", and "KC4UY" (above, manufactured by Konica Minolta Opto Co., Ltd.), etc. are mentioned.

Examples of commercially available cyclic olefin resins include "Topas" (registered trademark) (manufactured by Ticona (Germany)), "Aton" (registered trademark) (manufactured by JSR Corporation), and "ZEONOR" (registered trademark). , "ZEONEX" (registered trademark) (above, manufactured by Nippon Zeon Co., Ltd.) and "APEL" (registered trademark) (manufactured by Mitsui Chemicals Co., Ltd.). Such a cyclic olefin-based resin can be formed into a film by a known means such as a solvent casting method or a melt extrusion method to be used as a base material. A commercially available cyclic olefin resin base material can also be used. Examples of commercially available cyclic olefin resin substrates include "S-Sina" (registered trademark), "SCA40" (registered trademark) (above, manufactured by Sekisui Chemical Industry Co., Ltd.), and "Zeonoa Film" (registered trademark) (Optes). (manufactured by JSR Corporation) and "Aton Film" (registered trademark) (manufactured by JSR Corporation).

In terms of the thickness of the base material, a thin one is preferable in terms of a mass capable of practical handling, but if it is too thin, the strength tends to decrease and workability tends to deteriorate. The thickness of the substrate is usually 5 μm to 300 μm, preferably 20 μm to 200 μm. Moreover, additional thin film formation effect is acquired by peeling a base material and transferring only the polymer in the orientation state of a polymerizable liquid crystal compound.

[Alignment layer]

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

The alignment film preferably has solvent resistance that does not dissolve when the composition for forming a retardation layer is applied or the like, and has heat resistance in removal of the solvent or heat treatment for alignment of the polymerizable liquid crystal compound described later.

Such an alignment film facilitates orientation of the polymerizable liquid crystal compound. Moreover, control of various orientations, such as vertical orientation, horizontal orientation, hybrid orientation, and diagonal orientation, is possible by the type of orientation film, rubbing conditions, and light irradiation conditions.

As the alignment film forming the first retardation layer, an alignment film exhibiting an orientation 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 concave-convex pattern or a plurality of grooves on the surface. When applied to a long roll-shaped film, a photo-alignment film is preferable from the viewpoint of being able to easily control the orientation direction.

An orientation polymer can be used for the rubbing alignment film. Examples of the orienting polymer include polyamides and gelatins having an amide bond, polyimide having an imide bond and polyamic acid as a hydrolyzate thereof, polyvinyl alcohol, alkyl-modified polyvinyl alcohol, polyacrylamide, and polyoxa. sol, polyethyleneimine, polystyrene, polyvinylpyrrolidone, polyacrylic acid and polyacrylic acid esters. You may combine 2 or more types of orientation polymers.

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

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

Orienting polymer compositions are available from the market. Examples of commercially available orientation polymer compositions include SunEver (registered trademark, manufactured by Nissan Chemical Industries, Ltd.) and Optimer (registered trademark, manufactured by JSR Corporation).

As a method of applying the orienting polymer composition to the substrate, the same method as the method of applying the composition for forming a retardation layer described later to the substrate can be exemplified. As a method of removing the solvent contained in the orienting polymer composition, a natural drying method, an air drying method, a heat drying method, a reduced pressure drying method, and the like are exemplified.

As a method of the rubbing treatment, for example, a method in which a rubbing cloth is wound and the coating film is brought into contact with a rotating rubbing roll is exemplified. When performing the rubbing treatment, if masking is performed, a plurality of regions (patterns) having different alignment directions may be formed on the alignment film.

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

The photoreactive group refers to a group that generates orientation ability by light irradiation. Specifically, a group involved in a photoreaction that is the origin of orientation ability such as an orientation-inducing reaction, an isomerization reaction, a photodimerization reaction, a photocrosslinking reaction, or a photolysis reaction of molecules caused by light irradiation is exemplified. As the photoreactive group, a group having an unsaturated bond, particularly a double bond is preferable, and a carbon-carbon double bond (C=C bond), a carbon-nitrogen double bond (C=N bond), a nitrogen-nitrogen double bond (N=N bond) and a group having at least one selected from the group consisting of 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 structures such as aromatic Schiff base and aromatic hydrazone. Examples of the photoreactive group having an N=N bond include an azobenzene group, an azonaphthalene group, an aromatic heterocyclic azo group, a bisazo group, a formazan group, and a group having an azoxybenzene structure. Examples of the photoreactive group having a C=O bond include a benzophenone group, a coumarin group, an anthraquinone group and a maleimide group. These groups may have a substituent such as an alkyl group, an alkoxy group, an aryl group, an allyloxy group, a cyano group, an alkoxycarbonyl group, a hydroxyl group, a sulfonic acid group, or a halogenated alkyl group.

A group involved in a photodimerization reaction or a photocrosslinking reaction is preferred in terms of excellent orientation. Among them, the photoreactive group involved in the photodimerization reaction is preferable, the amount of polarized light irradiation required for orientation is relatively small, and it is easy to obtain a photo-alignment film with excellent thermal stability and time-lapse stability. desirable. As the polymer having a photoreactive group, those having a cinnamoyl group having a cinnamic acid structure or a cinnamic acid ester structure at the terminal portion of the side chain of the polymer are particularly preferable.

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

As a method of applying the composition for forming a photo-alignment layer to a substrate, the same method as the method of applying a composition for forming a retardation layer described below to a substrate may be used. As a method of removing the solvent from the applied composition for forming a photo-alignment layer, the same method as the method of removing the solvent from the orienting polymer composition may be used.

In order to irradiate polarized light, a form of directly irradiating polarized light to a composition for forming a photo-alignment layer applied on a substrate after removing the solvent may be used, or a type of irradiating polarized light from the substrate side and passing the polarized light through the substrate may be used. Further, it is preferable that the polarized light is substantially parallel light. The wavelength of the polarized light to be irradiated is preferably in a wavelength range in which the photoreactive group of the polymer or monomer having the photoreactive group can absorb light energy. Specifically, UV (ultraviolet rays) in the wavelength range of 250 nm to 400 nm is particularly preferred. As a light source for irradiating the polarized light, a xenon lamp, a high-pressure mercury lamp, an ultra-high pressure mercury lamp, a metal halide lamp, an ultraviolet light laser such as KrF or ArF, and the like are exemplified. Among them, high-pressure mercury lamps, ultra-high-pressure mercury lamps, and metal halide lamps are preferable because the emission intensity of ultraviolet rays with a wavelength of 313 nm is high. Polarized UV can be irradiated by irradiating light from the light source through an appropriate polarizing element. Examples of the polarization element include polarization filters, polarization prisms such as Glenn Thomson and Glenn Taylor, and wire grids. Among them, a wire-grid type polarizing element is preferable from the viewpoints of large area and resistance to heat.

In addition, when performing polarized light irradiation, if masking is performed, a plurality of regions (patterns) in which the directions of liquid crystal alignment are different can also be formed.

A groove alignment film is a film having a concavo-convex pattern or a plurality of grooves on the film surface. When a polymerizable liquid crystal compound is applied to a film having a plurality of linear grooves arranged at equal intervals, liquid crystal molecules are oriented in a direction along the grooves.

As a method of obtaining a groove alignment film, a method of forming a concavo-convex pattern by performing development and rinse treatment after exposure through an exposure mask having a pattern-shaped slit on the surface of the photosensitive polyimide film, a plate-shaped disk having grooves on the surface E, a method of forming a layer of UV curable resin before curing, transferring the resin layer to a substrate and then curing it, and pressing a roll-shaped disk having a plurality of grooves on a film of UV curable resin formed on the substrate before curing A method of forming irregularities and then curing them, and the like are exemplified.

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 orientation 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 fluorine-based polymers such as the orientation polymers and perfluoroalkyls described above, polyimide compounds, silane compounds, and polysiloxane compounds obtained by condensation reactions thereof. A silane compound is preferable from the point of being easy to reduce surface tension.

As the silane compound, a silicone type such as the above-mentioned silane coupling agent can be preferably applied. For example, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(2-methoxyethoxy)silane, N- (2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-glycidoxypropyltri Methoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxy Propyl dimethoxymethylsilane, 3-glycidoxypropylethoxydimethylsilane, etc. are mentioned. You may use 2 or more types of silane compounds.

The silane compound may be of a silicone monomer type or a silicone oligomer (polymer) type. When silicone oligomers are expressed in the form of a (monomer)-(monomer) copolymer, examples include the following.

3-Mercaptopropyltrimethoxysilane-tetramethoxysilane copolymer, 3-mercaptopropyltrimethoxysilane-tetraethoxysilane copolymer, 3-mercaptopropyltriethoxysilane-tetramethoxysilane copolymer , and copolymers containing a mercaptopropyl group such as 3-mercaptopropyltriethoxysilane-tetraethoxysilane copolymer;

Mercaptomethyltrimethoxysilane-tetramethoxysilane copolymer, mercaptomethyltrimethoxysilane-tetraethoxysilane copolymer, mercaptomethyltriethoxysilane-tetramethoxysilane copolymer, and mercaptomethyltri copolymers containing mercaptomethyl groups such as ethoxysilane-tetraethoxysilane copolymers;

3-methacryloyloxypropyltrimethoxysilane-tetramethoxysilane copolymer, 3-methacryloyloxypropyltrimethoxysilane-tetraethoxysilane copolymer, 3-methacryloyloxypropyltrie Toxysilane-tetramethoxysilane copolymer, 3-methacryloyloxypropyltriethoxysilane-tetraethoxysilane copolymer, 3-methacryloyloxypropylmethyldimethoxysilane-tetramethoxysilane copolymer, 3-methacryloyloxypropylmethyldimethoxysilane-tetraethoxysilane copolymer, 3-methacryloyloxypropylmethyldiethoxysilane-tetramethoxysilane copolymer, and 3-methacryloyloxypropylmethyl copolymers containing methacryloyloxypropyl groups such as diethoxysilane-tetraethoxysilane copolymers;

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

Vinyltrimethoxysilane-tetramethoxysilane copolymer, Vinyltrimethoxysilane-tetraethoxysilane copolymer, Vinyltriethoxysilane-tetramethoxysilane copolymer, Vinyltriethoxysilane-tetraethoxysilane copolymer Polymers, vinylmethyldimethoxysilane-tetramethoxysilane copolymer, vinylmethyldimethoxysilane-tetraethoxysilane copolymer, vinylmethyldiethoxysilane-tetramethoxysilane copolymer, and vinylmethyldiethoxysilane-tetrae copolymers containing a vinyl group such as a toxysilane 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-aminopropyl amino group-containing copolymers such as methyldiethoxysilane-tetramethoxysilane copolymer, and 3-aminopropylmethyldiethoxysilane-tetraethoxysilane copolymer; and the like.

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

As a method of applying the vertical alignment film to the substrate, the same method as the method of applying the composition for forming a retardation layer to be described below to the substrate may be mentioned. As a method of removing the solvent from the applied composition for forming a photo-alignment layer, the same method as the method of removing the solvent from the orienting polymer composition may be used.

The thickness of the alignment film for forming the second retardation layer is usually in the range of 10 to 10000 nm, preferably in the range of 50 to 5000 nm, and more preferably in the range of 100 to 500 nm.

<Method of manufacturing phase contrast layer>

<Application of composition for forming retardation layer>

A retardation layer may be formed by applying a composition for forming a retardation layer on the substrate or the alignment layer. Examples of the method for applying the composition for forming a retardation layer on a substrate include an extrusion coating method, a direct gravure coating method, a reverse gravure coating method, a CAP coating method, a slit coating method, a micro gravure method, a die coating method, an inkjet method, and the like. can Moreover, the method of apply|coating using the coater, such as a dip coater, a bar coater, and a spin coater, etc. are mentioned. Among them, in the case of continuous application in a roll to roll format, a coating method by a microgravure method, an inkjet method, a slit coating method, or a die coating method is preferable, and in the case of application to a sheet substrate such as glass For this, spin coating with high uniformity is preferred.

<Drying the composition for forming the retardation layer>

Examples of the drying method for removing the solvent contained in the composition for forming a retardation layer include natural drying, air drying, heat drying, vacuum drying, and a combination thereof. Especially, natural drying or heat drying is preferable. 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 from 10 seconds to 20 minutes, more preferably from 30 seconds to 10 minutes. The composition for forming a photo-alignment layer and the orientation polymer composition may also be dried in the same manner.

<Polymerization of polymerizable liquid crystal compound>

As a method of polymerizing a polymerizable liquid crystal compound, photopolymerization is preferable. Photopolymerization is performed by irradiating active energy rays to a layered product coated with a composition for forming a retardation layer containing a polymerizable liquid crystal compound on a substrate or an alignment film. As the active energy ray to be irradiated, 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), the type of photopolymerization initiator in the case of containing a photopolymerization initiator, and appropriately selected according to their quantity. Specifically, one or more types of light selected from the group consisting of visible light, ultraviolet light, infrared light, X-rays, α-rays, β-rays, and γ-rays is exemplified. 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 the art can be used, and photopolymerization is possible by ultraviolet light. It is preferable to select the kind of liquid crystal compound.

As the light source of the active energy ray, for example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultra-high pressure mercury lamp, a xenon lamp, a halogen lamp, a carbon arc lamp, a tungsten lamp, a gallium lamp, an excimer laser, a wavelength range of 380 An LED light source emitting light of -440 nm, a chemical lamp, a black light lamp, a microwave excited mercury lamp, a metal halide lamp, and the like are exemplified.

The ultraviolet irradiation intensity is usually 10 mW/cm 2 to 3,000 mW/cm 2 . The ultraviolet irradiation intensity is preferably an intensity in a wavelength range effective for activation of a cationic polymerization initiator or a radical polymerization initiator. The light irradiation time is usually 0.1 second to 10 minutes, preferably 0.1 second to 5 minutes, more preferably 0.1 second to 3 minutes, still more preferably 0.1 second to 1 minute. When irradiated once or multiple times at such an ultraviolet irradiation intensity, the integrated light amount 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 . ~ 1,000 mJ/cm 2 . When the cumulative amount of light is less than this range, curing of the polymerizable liquid crystal compound may become insufficient and good transferability may not be obtained. Conversely, when the integrated light amount is more than this range, the optical film containing the retardation layer may be colored.

[Polarizer]

The elliptically polarizing plate of the present invention is composed of a polarizing plate and the optical film of the present invention. For example, the elliptically polarizing plate of the present invention can be obtained by bonding the polarizing plate and the optical film of the present invention together via a pressure-sensitive adhesive or an adhesive layer. can

In one embodiment of the present invention, when the polarizing plate and the optical film of the present invention are laminated, it is preferable to laminate such that the slow axis (optical axis) of the first retardation layer and the absorption axis of the polarizing plate are substantially 45°. A function as a circularly polarizing plate can be obtained by laminating the optical film of the present invention so that the slow axis (optical axis) and the absorption axis of the polarizing plate are substantially 45°. In addition, substantially 45 degrees is usually in the range of 45 ± 5 degrees.

As a polarizing plate, it consists of a polarizer having a polarizing function. Examples of the polarizer include a stretched film to which a dye having absorption anisotropy is adsorbed, or a film in which a dye having absorption anisotropy is applied and oriented. A dichroic dye is mentioned as a dye which has absorption anisotropy.

The stretched film to which the dye having absorption anisotropy is adsorbed is usually a step of uniaxially stretching the polyvinyl alcohol-based resin film, a step of dyeing the polyvinyl alcohol-based resin film with a dichroic dye, and adsorbing the dichroic dye, It is manufactured through a process of treating a polyvinyl alcohol-based resin film adsorbed with a dichroic dye with an aqueous solution of boric acid, and a process of washing with water after treatment with an aqueous solution of boric acid. A polarizing plate is obtained by bonding together the polarizer obtained in this way and the transparent protective film. As a dichroic dye, iodine and a dichroic organic dye are mentioned. Examples of dichroic organic dyes 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 the polarizer obtained by subjecting the polyvinyl alcohol-based resin film to uniaxial stretching, dyeing with a dichroic dye, boric acid treatment, washing with water and drying is preferably 5 μm to 40 μm.

[Adhesive]

As the adhesive agent for bonding the polarizing plate and the optical film of the present invention or the optical film of the present invention and a display device, a pressure-sensitive adhesive, a dry solidification adhesive, and a chemical reaction adhesive are exemplified. As a chemical reaction type adhesive agent, an active energy ray hardening type adhesive agent is mentioned, for example. As the adhesive agent between the polarizing plate and the optical film of the present invention, an adhesive layer formed of a pressure-sensitive adhesive, a dry solidifying adhesive, or an active energy ray curable adhesive is preferable. As an adhesive agent between the optical film of the present invention and a display device, , a pressure-sensitive adhesive or an active energy ray curable adhesive is preferred.

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 adhesives containing acrylic polymers are excellent in optical transparency, have appropriate wettability and cohesiveness, are excellent in adhesiveness, and have high weatherability and heat resistance, and are resistant to floating or floating under conditions of heating or humidification. This is preferable because peeling or the like does not occur easily.

As the acrylic polymer, (meth)acrylates in which the alkyl group of the ester moiety is an alkyl group having 1 to 20 carbon atoms such as methyl, ethyl, or butyl (hereinafter, acrylates and methacrylates are collectively referred to as (meth)acrylates). A copolymer of acrylic acid and methacrylic acid (sometimes collectively referred to as (meth)acrylic acid) and a (meth)acrylic monomer having a functional group such as (meth)acrylic acid or hydroxyethyl (meth)acrylate is preferred. do.

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

As a solvent, the solvent etc. which were illustrated as the said solvent are mentioned. The pressure-sensitive adhesive may contain a light diffusing agent. The light-diffusing agent is an additive that imparts light-diffusing properties to the pressure-sensitive adhesive, and may be fine particles having a refractive index different from that of the polymer contained in the pressure-sensitive adhesive. Examples of the light diffusing agent include fine particles composed of inorganic compounds and fine particles composed of organic compounds (polymers). Since many of the polymers contained as active ingredients in the pressure-sensitive adhesive, including acrylic polymers, have a refractive index of about 1.4 to 1.6, it is preferable to appropriately select from light diffusing agents having a refractive index of 1.2 to 1.8. The difference in refractive index 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 brightness and displayability of the display device. The fine particles used as the light-diffusing agent are preferably spherical fine particles, which are also 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 declination method or an Abbe refractometer.

Examples of fine particles made of an inorganic compound include aluminum oxide (refractive index 1.76) and silicon oxide (refractive index 1.45). As the fine particles composed of organic compounds (polymers), 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 resin beads (refractive index 1.46). The content of the light diffusing agent is usually from 3 parts by mass to 30 parts by mass with respect to 100 parts by mass of the polymer.

The thickness of the pressure-sensitive adhesive is not particularly limited since it is determined depending on its adhesion and the like, but is usually 1 μm to 40 μm. From the viewpoint of workability, durability, etc., the thickness is preferably from 3 µm to 25 µm, and more preferably from 5 µm to 20 µm. By setting the thickness of the pressure-sensitive adhesive layer formed of the pressure-sensitive adhesive to 5 μm to 20 μm, the brightness of the display device is maintained when viewed from the front or when viewed from an angle, and blurring or blurring of the displayed image can be easily prevented. .

[Dry solidification adhesive]

The dry solidification adhesive may contain a solvent.

As the dry solidified adhesive, 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 is contained as a main component, and further a polyhydric aldehyde, an epoxy compound, an epoxy resin, a melamine compound, A composition containing a zirconia compound and a crosslinking agent such as a zinc compound or a curable compound; and the like are exemplified. Examples of polymers of monomers having a protonic functional group such as a hydroxyl group, a carboxyl group or an amino group and an ethylenically unsaturated group include ethylene-maleic acid copolymers, itaconic acid copolymers, acrylic acid copolymers, acrylamide copolymers, saponified products of polyvinyl acetate, and polyvinyl alcohol-based resins.

As the polyvinyl alcohol-based resin, 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 etc. are mentioned. The content of the polyvinyl alcohol-based resin in the aqueous adhesive agent 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.

As a urethane resin, a polyester-type ionomer type urethane resin etc. are mentioned.

The polyester ionomer type urethane resin referred to herein is a urethane resin having a polyester skeleton, into which a small amount of ionic component (hydrophilic component) is introduced. Since such an ionomer type urethane resin is emulsified in water to form an emulsion without using an emulsifier, it can be used as an aqueous adhesive. When using a polyester ionomer type urethane resin, it is effective to mix|blend a water-soluble epoxy compound as a crosslinking agent.

As the epoxy resin, polyamide epoxy obtained by reacting epichlorohydrin with polyamide polyamine obtained by reaction of polyalkylene polyamine such as diethylenetriamine or triethylenetetramine with dicarboxylic acid such as adipic acid Resin etc. are mentioned. Examples of commercially available products of such polyamide epoxy resin include "Sumirez Resin (registered trademark) 650" and "Sumirez Resin 675" (above, manufactured by Sumika Chemtex Co., Ltd.), "WS-525" (manufactured by Nippon PMC Co., Ltd.), and the like. can be heard When blending the epoxy resin, the amount of addition is usually 1 part by mass to 100 parts by mass, preferably 1 part by mass to 50 parts by mass, based on 100 parts by mass of the polyvinyl alcohol-based resin.

The thickness of the adhesive layer formed from the dry solidified 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. If the adhesive layer formed from the dry solidified adhesive is too thick, poor appearance tends to occur in, for example, the polarizing plate and the elliptically polarizing plate formed of the optical film of the present invention.

[Active energy ray curing adhesive]

The active energy ray curable adhesive may contain a solvent. An active energy ray curable adhesive is an adhesive that is cured by receiving irradiation of an active energy ray.

As the active energy ray curing type adhesive, a cationically polymerizable adhesive containing an epoxy compound and a cationic polymerization initiator, a radically polymerizable adhesive containing an acrylic curing component and a radical polymerization initiator, a cationically polymerizable curing component such as an epoxy compound, and adhesives containing both radically polymerizable curing components such as acrylic compounds, and further containing a cationic polymerization initiator and a radical polymerization initiator; and adhesives cured by irradiation with electron beams without containing these polymerization initiators. .

Among them, a radically polymerizable active energy ray curable adhesive containing an acrylic curing component and a radical polymerization initiator, and a cationically polymerizable active energy ray curable adhesive containing an epoxy compound and a cationic polymerization initiator are 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 compounds other than an epoxy compound. Examples of compounds other than epoxy compounds include oxetane compounds and acrylic compounds.

As a radical polymerization initiator, the photoinitiator mentioned above is mentioned. Commercially available products of the cationic polymerization initiator include "Kayarad" (registered trademark) series (manufactured by Nippon Kayaku Co., Ltd.), "Cyracure UVI" series (manufactured by Dow Chemical Co., Ltd.), "CPI" series (manufactured by San-Apro Co., Ltd.), “TAZ”, “BBI”, and “DTS” (above, manufactured by Midori Chemical Co., Ltd.), “Adeka Optomer” series (manufactured by ADEKA Corporation), “RHODORSIL” (registered trademark) (manufactured by Rhodia Corporation), and the like. . The content of the radical polymerization initiator and the cationic polymerization initiator is usually 0.5 part 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.

The active energy ray-curable adhesive may further contain an ion trapping agent, an antioxidant, a chain transfer agent, a tackifier, a thermoplastic resin, a filler, a flow regulator, a plasticizer, and an antifoaming agent.

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, electron beams, and the like, and ultraviolet rays and electron beams are preferable. Preferable ultraviolet irradiation conditions are the same as those for polymerization of the above-described polymerizable liquid crystal compound.

[Display device]

As one of the embodiments, the present invention can provide a display device including the optical film of the present invention. Further, the display device may include the elliptically polarizing plate according to the above 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. As the display device, a liquid crystal display device, an organic electroluminescence (EL) display device, an inorganic electroluminescence (EL) display device, a touch panel display device, an electron emission display device (electric field emission display device (FED, etc.), surface field emission display (SED)), electronic paper (display device using electronic ink or electrophoretic element), plasma display device, projection type display device (grating light valve (GLV) display device, digital micro mirror device (DMD)) a display device having the same), a piezoelectric ceramic display, and the like.

The liquid crystal display device includes any one of a transmission type liquid crystal display device, a transflective type liquid crystal display device, a reflection type liquid crystal display device, a direct view type liquid crystal display device, and a projection type liquid crystal display device. These display devices may be display devices that display two-dimensional images or stereoscopic display devices that display three-dimensional images. In particular, as a display device provided with the optical film and polarizing plate which consist of this invention, an organic electroluminescent display device and a touch panel display device are preferable.

[Example]

Hereinafter, the present invention will be described in more detail by examples. In addition, "%" and "part" in an example mean mass % and a mass part, unless otherwise indicated. In addition, the polymer film, apparatus, and measurement method used in the following examples are as follows.

-ZF-14 manufactured by Nippon Zeon Co., Ltd. was used for the cycloolefin polymer (COP) film.

· For the corona treatment device, AGF-B10 manufactured by Kasuga Electric Co., Ltd. was used.

- The corona treatment was performed once using the 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 manufactured by Ushio Electric Co., Ltd. was used for the polarization UV irradiation device.

- Unicure VB-15201BY-A manufactured by Ushio Electric Co., Ltd. was used for the high-pressure mercury lamp.

• The phase difference value Re (λ) in the in-plane direction was measured using KOBRA-WPR manufactured by Oji Instruments Co., Ltd.

• The retardation value Rth (λ) in the thickness direction and the film thickness were measured using an ellipsometer M-220 manufactured by Nippon Spectroscopy Corporation.

[Preparation of Alignment Film Composition for Forming First Phase Difference Layer]

By mixing 5 parts of the photo-alignment material having the following structure (weight average molecular weight: 30000) and 95 parts of cyclopentanone (solvent) as components and stirring the resulting mixture at 80°C for 1 hour, an alignment film composition for forming the first phase difference layer was obtained. got it

[Preparation of Alignment Film Composition for Forming Second Phase Contrast Layer]

A silane coupling agent KBE-9103 manufactured by Shin-Etsu Chemical Co., Ltd. was dissolved in a mixed solvent in which ethanol and water were mixed at a ratio of 9:1 (weight ratio) to obtain an alignment film composition for forming a 1% solid content second phase difference layer. .

[Preparation of Compositions for Forming First and Second Phase Difference Layers (Compositions I to IV)]

For the mixture of the polymerizable liquid crystal compound A and the polymerizable liquid crystal compound B described below, 0.1 part of a leveling agent (F-556; manufactured by DIC) and a polymerization initiator 2-dimethylamino-2-benzyl-1-( 6 parts of 4-morpholinophenyl) butan-1-one (Irgacure 369 (Irg369); manufactured by BASF Japan Co., Ltd.) was added.

Furthermore, N-methyl-2-pyrrolidone (NMP) was added as a solvent so that the solid content concentration was 13%, and the first and second retardation layer forming compositions were obtained by stirring at 80°C for 1 hour. In addition, the mixture ratio of the polymerizable liquid crystal compound A and the polymerizable liquid crystal compound B is added as described in Table 1 according to the target wavelength dispersion value α, and the name of each composition is as described in Table 1. together

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

Polymeric liquid crystal compound A was manufactured by the method described in Unexamined-Japanese-Patent No. 2010-31223. Moreover, polymeric liquid crystal compound B was manufactured according to the method of Unexamined-Japanese-Patent No. 2009-173893. Each molecular structure is shown below.

[Preparation of Liquid Crystal Composition for Forming First and Second Retardation Layers (Composition V)]

To the liquid crystal compound LC242 described below: PaliocolorLC242 (registered trademark of BASF), 0.1 part of leveling agent F-556 and 3 parts of polymerization initiator Irg369 were added, and cyclopentanone was added so that the solid content concentration was 13%, A liquid crystal composition for forming the first and second retardation layers was obtained. Let the name of the obtained liquid crystal composition be "composition V".

Liquid crystal compound LC242: Paliocolor LC242 (registered trademark of BASF)

(Example 1)

[Manufacture of first phase difference layer]

On a COP film (ZF-14-50) manufactured by Nippon Zeon Co., Ltd., the alignment film composition for forming the first retardation layer was applied using a bar coater, dried at 80 ° C. for 1 minute, and polarized UV irradiation device (SPOT CURE SP-9; manufactured by Ushio Electric Co., Ltd.) was used, and polarized UV exposure was performed at a wavelength of 313 nm, an integrated light amount of 100 mJ/cm 2 and an axial angle of 45°. It was 100 nm as a result of measuring the film thickness of the obtained 1st orientation film for retardation layer formation with an ellipsometer.

Subsequently, composition I was applied to the alignment film for forming the first retardation layer using a bar coater, dried at 120 ° C. for 1 minute, and then a high-pressure mercury lamp (Unicure VB-15201BY-A, manufactured by Ushio Electric Co., Ltd.) was used. Then, the first retardation layer was formed by irradiating ultraviolet rays from the surface side to which the composition of the retardation layer was applied (in a nitrogen atmosphere, a cumulative amount of light at a wavelength of 365 nm: 500 mJ/cm 2 ). It was 2.3 micrometers as a result of measuring the film thickness of the obtained 1st retardation layer with the ellipsometer.

[Manufacture of Second Phase Contrast Layer]

On a COP film (ZF-14-50) manufactured by Nippon Zeon Co., Ltd., an alignment film composition for forming a second phase difference layer is applied using a bar coater, dried at 120°C for 1 minute, and an alignment film for forming a second phase difference layer got It was 200 nm as a result of measuring the film thickness of the obtained 2nd orientation film for retardation layer formation with an ellipsometer.

Subsequently, composition I was applied to the alignment film for forming the second phase difference layer using a bar coater, and after drying at 120° C. for 1 minute, a high-pressure mercury lamp (Unicure VB-15201BY-A, manufactured by Ushio Electric Co., Ltd.) was used. Then, the second retardation layer was formed by irradiating ultraviolet rays from the side of the surface to which the composition of the retardation layer was applied (accumulated light amount at a wavelength of 365 nm in a nitrogen atmosphere: 500 mJ/cm 2 ). As a result of measuring the film thickness of the obtained second retardation layer with an ellipsometer, it was 1.2 µm.

[Re measurement of the first retardation layer and the second retardation layer]

The in-plane retardation values (Re1 (λ) and Re2 (λ)) of the first retardation layer and the second retardation layer prepared by the above method were measured by a measuring instrument (KOBRA-WR, manufactured by Oji Measuring Instrument Co., Ltd.), and measured at wavelengths λ of 450 nm, 550 nm, and 650 nm, respectively. The obtained results are shown in Table 2.

[Rth measurement of the first retardation layer and the second retardation layer]

The thickness direction retardation values (Rth1 (λ) and Rth2 (λ)) of the first retardation layer and the second retardation layer prepared by the above method were determined by an ellipsometer after confirming that there was no retardation in the cycloolefin polymer film as the substrate. The measurement was performed by changing the incident angle of light to the sample. In addition, the average refractive index in the wavelength λ of 450 nm and 550 nm was measured using a refractometer (“multi-wavelength Abbe refractometer DR-M4” manufactured by Atago Co., Ltd.). Table 2 shows 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 formula (C). The calculated result is shown in Table 2.

In addition, the refractive indices nx1 (λ), ny1 (λ), and nz1 (λ) of the obtained first retardation layer are nx1 (λ) > ny1 (λ) ≒ nz1 (λ) in the entire region of the wavelength λ = 400 to 700 nm satisfies In addition, the refractive indices nx2 (λ), ny2 (λ), and nz2 (λ) of the second retardation layer are nz2 (λ) > nx2 (λ) ≒ ny2 (λ) in the entire wavelength range satisfy

[Manufacture of polarizing plate]

A polyvinyl alcohol film having an average degree of polymerization of about 2,400 and a degree of saponification of 99.9 mol% or more and having a thickness of 75 μm was immersed in pure water at 30 ° C., and then immersed in an aqueous solution containing iodine / potassium iodide / water in a weight ratio of 0.02/2/100 at 30 ° C. Iodine dyeing was performed by immersion (iodine dyeing process). The polyvinyl alcohol film that had undergone 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). After washing the polyvinyl alcohol film subjected to the boric acid treatment step with pure water at 8°C, it was dried at 65°C to obtain a polarizer (27 µm in thickness after stretching) in which iodine was adsorbed and oriented to polyvinyl alcohol. At this time, stretching was performed in the iodine dyeing process and the boric acid treatment process. The total stretching ratio in this stretching was 5.3 times. The obtained polarizer and the saponified triacetyl cellulose film (KC4UYTAC 40 µm manufactured by Konica Minolta) were bonded together with a nip roll through a water-based adhesive. It was made to dry at 60 degreeC for 2 minute(s), maintaining the tension|tensile_strength of the obtained adhesive substance at 430 N/m, and the polarizing plate which has a triacetyl cellulose film as a protective film on one side was obtained. In addition, the water-based adhesive is 100 parts of water, 3 parts of carboxyl group-modified polyvinyl alcohol (Kurarepoval KL318 manufactured by Kuraray), and a water-soluble polyamide epoxy resin (Sumirez Resin 650 manufactured by Sumika ChemteX, 30% aqueous solution of solid content concentration). It was prepared by adding 1.5 parts.

Optical characteristics of the obtained polarizing plate were measured. The measurement was performed with a spectrophotometer (V7100, manufactured by Nippon Spectrophotometer) using the polarizer plane of the polarizing plate obtained above as the incident plane. The obtained visibility corrected single transmittance was 42.1%, the visibility corrected polarization was 99.996%, the single color a was -1.1, and the single color b was 3.7.

[Manufacture of elliptically polarizing plate]

First, after corona treatment was performed on the surface of the first retardation layer, the polarizing plate manufactured by the above method was bonded through an adhesive (5 μm pressure-sensitive adhesive manufactured by Lintec), and then the substrate was peeled to obtain a first retardation with the polarizing plate A stack of layers was formed.

Subsequently, after corona treatment was performed on the surface of the second phase difference layer, the first phase difference layer and the second phase difference in the laminate of the polarizing plate and the first phase difference layer were applied through an adhesive (5 µm pressure-sensitive adhesive manufactured by Lintec). layers were bonded. Thereafter, the substrate was peeled off to prepare an elliptically polarizing plate.

[Confirmation of frontal color and color change in all directions]

After bonding the obtained elliptically polarizing plate to a mirror through an adhesive, it was visually observed from a place 50 cm away from the front to confirm the hue. In addition, it was observed with the naked eye from a place 50 cm away from an elevation angle of 60° and an azimuth angle of 0 to 360°, and color in all directions was confirmed. The confirmed result is shown in Table 2.

In addition, the front color and the four sides color 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 manufactured in the same manner as in Example 1, except that Composition I was changed to Composition II, Composition III, Composition IV, or Composition V, respectively, according to the description in Table 2. Each measurement result is shown in Table 2.

In addition, the refractive indices 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). In addition, the refractive indices nx2 (λ), ny2 (λ), and nz2 (λ) of the second retardation layer are nz2 (λ) > nx2 (λ) ≒ ny2 (λ) in the entire wavelength range satisfy

(Example 31)

Composition I was changed according to the description in Table 2, and the lamination order of the first retardation layer and the second retardation layer in the manufacturing method of the elliptically polarizing plate was first laminated with the polarizing plate and the second retardation layer, followed by the polarizing plate and the second retardation layer. An optical film and an elliptically polarizing plate were manufactured in the same manner as in Example 1, except that the order of laminating the laminate of the two phase difference layers and the first phase difference layer was changed. Table 2 shows the measurement results.

In addition, the refractive indices nx1 (λ), ny1 (λ), and nz1 (λ) of the first retardation layer obtained in Example 31 are nx1 (λ) > ny1 (λ) ≒ in the entire wavelength range of λ = 400 to 700 nm. satisfies nz1 (λ). In addition, the refractive indices nx2 (λ), ny2 (λ), and nz2 (λ) of the second retardation layer are nz2 (λ) > nx2 (λ) ≒ ny2 (λ) in the entire wavelength range satisfy

The elliptically polarizing plate having the first retardation layer and the second retardation layer described in Examples has a front color and a black color on all sides, and has excellent antireflection properties.

Claims (12)

It has a first retardation layer and a second retardation layer, and satisfies the relationship of the following formulas (1) and (2),
0.4 ≤ Nz (450) ≤ 0.6 (1)
0.4 ≤ Nz (550) ≤ 0.6 (2)
[Wherein, Nz (450) denotes the Nz coefficient of the optical film for light of wavelength λ = 450 nm, Nz (550) denotes the Nz coefficient of the optical film for light of wavelength λ = 550 nm, respectively, and the wavelength λ The Nz coefficient Nz (λ) of the optical film for light of (nm) is
Nz (λ) = (nx (λ) - nz (λ)) / (nx (λ) - ny (λ))
indicated by nx (λ) represents the principal refractive index of light having a wavelength of λ (nm) in a direction parallel to the film plane in the refractive index ellipsoid formed by the optical film. ny (λ) represents the refractive index of the refractive index ellipsoid formed by the optical film in a direction parallel to the film plane for 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 film plane for light of wavelength λ (nm) in the refractive index ellipsoid formed by the optical film.]
The first phase difference layer,
In the refractive index ellipsoid formed by the first retardation layer, in the range of wavelength λ = 400 to 700 nm, nx1 (λ) > ny1 (λ) ≒ nz1 (λ)
[In the formula, nx1 (λ) represents the principal refractive index of light having a wavelength of λ (nm) in a direction parallel to the film plane in the refractive index ellipsoid formed by the first retardation layer. ny1 (λ) represents the refractive index for light of wavelength λ (nm) in a direction parallel to the film plane and orthogonal to the direction of nx1 (λ) in the refractive index ellipsoid formed by the first retardation layer . In the refractive index ellipsoid formed by the first retardation layer, nz1 (λ) represents the refractive index of light of wavelength λ (nm) in a direction perpendicular to the film plane.]
have a relationship with
Satisfy the relationship of the following formulas (3) and (4),
0.75 ≤ Re1 (450) / Re1 (550) ≤ 0.92 (3)
1.00 ≤ Re1 (650)/Re1 (550) (4)
[Wherein, Re1 (450) is the in-plane retardation value of the first retardation layer for light with a wavelength of λ = 450 nm, Re1 (550) is the in-plane retardation value of the first retardation layer for light with a wavelength of λ = 550 nm Re1 (650) represents the in-plane retardation value of the first retardation layer for light with a wavelength of λ = 650 nm, respectively, and the in-plane retardation value of the first retardation layer for light with a wavelength of λ nm Re1 (λ) is,
Re1 (λ) = (nx1 (λ) - ny1 (λ)) × d1
represented by Here, d1 represents the thickness of the first retardation layer.]
The second retardation layer,
In the refractive index ellipsoid formed by the second retardation layer, in the range of wavelength λ = 400 to 700 nm, nz2 (λ) > nx2 (λ) ≈ ny2 (λ)
[In the formula, nz2 (λ) represents the refractive index in the direction perpendicular to the film plane for light having a wavelength of λ (nm) 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 for light having a wavelength of λ (nm) in the refractive index ellipsoid formed by the second retardation layer. ny2(λ) represents the refractive index for light having a wavelength λ (nm) in a direction parallel to the film plane and orthogonal to the direction of nx2 in the refractive index ellipsoid formed by the second retardation layer. However, when nx2 (λ) = ny2 (λ), nx2 (λ) represents the refractive index in an arbitrary direction parallel to the film plane.]
have a relationship with
Satisfy the relationship of the following formulas (5) and (6),
0.75 ≤ Rth2 (450) / Rth2 (550) ≤ 0.92 (5)
1.00 ≤ Rth2 (650)/Rth2 (550) (6)
[Wherein, Rth2 (450) is the retardation value in the thickness direction for light with a wavelength of λ = 450 nm, and Rth2 (550) is the retardation value in the thickness direction of the second retardation layer for light with a wavelength of λ = 550 nm. , Rth2 (650) represent the retardation value in the thickness direction of the second retardation layer for light with a wavelength of 650 nm, respectively, and the retardation value in the thickness direction of the second retardation layer for light with a wavelength of λ (nm) Rth2 (λ) Is,
Rth2 (λ) = [(nx2 (λ) + ny2 (λ))/2 - nz2 (λ)] × d2
represented by Here, in the refractive index ellipsoid formed by the second retardation layer, nz2 (λ) represents the principal refractive index in the direction perpendicular to the film plane at the wavelength λ (nm), ((nx2 (λ) + ny2 (λ) )/2) represents the average refractive index in the film plane at the wavelength λ (nm). d2 represents the thickness of the second retardation layer.]
The first retardation layer is a liquid crystal cured film cured in a state in which the polymerizable liquid crystal compound is oriented in a horizontal direction with respect to the substrate surface,
The second retardation layer is an optical film that is a liquid crystal cured film cured in a state in which a polymerizable liquid crystal compound is aligned in a direction perpendicular to the substrate surface. According to claim 1,
An optical film in which the second retardation layer is a film composed of a coating layer formed by polymerizing polymerizable liquid crystals in an aligned state. According to claim 1 or 2,
An optical film comprising a coating layer formed by polymerizing polymerizable liquid crystals in a state in which the first retardation layer is aligned. According to any one of claims 1 to 3,
An optical film in which the second retardation layer is 5 μm or less. According to any one of claims 1 to 4,
An optical film having a first retardation layer of 5 μm or less. According to any one of claims 1 to 5,
An optical film in which 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 provided with an optical compensation function comprising the optical film according to any one of claims 1 to 6 and a polarizing plate. According to claim 7,
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 ° within the film plane, and the absorption axis of the polarizing plate and the slow axis of the first retardation layer and the slow axis of the second retardation layer An elliptically polarizing plate endowed with an optical compensation function whose axis is orthogonal to the film plane in the vertical direction. According to claim 7 or 8,
An elliptically polarizing plate provided with an optical compensation function, which is an optical laminate comprising a polarizing plate, a point adhesive layer, a first retardation layer, a point adhesion layer, and a second retardation layer formed in this order. According to claim 7 or 8,
An elliptically polarizing plate with an optical compensation function, which is an optical laminate comprising a polarizing plate, an adhesive layer, a second retardation layer, an adhesive layer, and a first retardation layer formed in this order. An organic EL display device comprising the elliptically polarizing plate provided with the optical compensation function according to any one of claims 8 to 10. A method for producing an elliptically polarizing plate provided with an optical compensation function according to any one of claims 7 to 10, including all of the following steps.
(Step 1-A) A step of forming a first retardation layer by applying a polymerizable liquid crystal compound on a substrate on which a horizontal alignment film is formed and then polymerizing the compound 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 it in a vertically aligned state;
(Step 2) A step of transferring the liquid crystal polymer of the first retardation layer and the liquid crystal polymer of the second retardation layer from the base material through an adhesive agent and laminating them on a polarizing plate.