CN114942488B - Optical film and method for producing same - Google Patents

Abstract

The present invention provides a novel optical film in which light refractive index is controlled in three dimensions for all viewing directions and around visible light Quan Fan, and a method for manufacturing the same. An optical film having a first phase difference layer and a second phase difference layer and satisfying the relationship of the following formulas (1) and (2). (1) Nz (450) is more than or equal to 0.4 and less than or equal to 0.6, and (2) Nz (550) is more than or equal to 0.4 and less than or equal to 0.6. Where Nz (450) represents the Nz coefficient of the optical film for light having a wavelength of λ=450 nm, and Nz (550) represents the Nz coefficient of the optical film for light having a wavelength of λ=550 nm, respectively.

Description

Optical film and method for producing same

The application is a divisional application of Chinese patent application No.201810146736.8 with the application date of 2018, 2-month and 12-date and the name of 'optical film and manufacturing method thereof'.

Technical Field

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

Background

In a Flat Panel Display (FPD), an optical film such as a polarizing plate or a retardation plate may be used. For a retardation plate, it is required to realize uniform phase conversion over the entire visible light range, and for example, patent document 1 discloses an inverse wavelength dispersive retardation film oriented in the horizontal direction, and patent document 2 discloses an inverse wavelength dispersive retardation film oriented in the vertical direction.

Prior art literature

Patent literature

Patent document 1: japanese patent application laid-open No. 2010-537955

Patent document 2: japanese patent application laid-open No. 2015-57646

Disclosure of Invention

Problems to be solved by the invention

In recent years, with the evolution of flat panel displays, it has been demanded to present clear black display from any direction. Therefore, the following problems become more apparent: it is not sufficient to perform only the wavelength dispersion control in the horizontal direction or the vertical direction.

Means for solving the problems

The present invention includes the following inventions.

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

0.4≤Nz(450)≤0.6 (1)

0.4≤Nz(550)≤0.6 (2)

[ Formula (i), nz (450) represents the Nz coefficient of the optical film for light having a wavelength of λ=450 nm, nz (550) represents the Nz coefficient of the optical film for light having a wavelength of λ=550 nm, and Nz coefficient of the optical film for light having a wavelength of λ (nm) (λ) is represented by the following formula:

Nz(λ)＝(nx(λ)-nz(λ))/(nx(λ)-ny(λ))

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

Nz (λ) represents: in an ellipsoid of refractive index formed by an optical film, the refractive index of light of wavelength λ (nm) in a direction perpendicular to the film plane. A kind of electronic device

The optical film according to [ 2 ] above, wherein, for the first retardation layer,

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

[ In the formula, nx1 (λ) represents: in the refractive index ellipsoid formed by the first phase difference layer, the principal refractive index of light of wavelength λ (nm) in a direction parallel to the film plane. ny1 (λ) represents: in the refractive index ellipsoid formed by the first retardation layer, the refractive index of light having a wavelength λ (nm) in a direction parallel to the film plane and orthogonal to the direction of nx1 (λ) is measured. nz1 (λ) represents: in the refractive index ellipsoid formed by the first phase difference layer, the refractive index of light of wavelength λ (nm) in the direction perpendicular to the film plane is increased. A kind of electronic device

The first retardation layer satisfies the relationship between the following formulas (3) and (4).

Re1(450)/Re1(550)≤1.00 (3)

1.00≤Re1(650)/Re1(550) (4)

[ Wherein Re1 (450) represents the in-plane phase difference value of the first retardation layer for light having a wavelength of λ=450nm, re1 (550) represents the in-plane phase difference value of the first retardation layer for light having a wavelength of λ=550 nm, re1 (650) represents the in-plane phase difference value of the first retardation layer for light having a wavelength of λ=650 nm, and Re1 (λ) represents the in-plane phase difference value of the first retardation layer for light having a wavelength of λ nm by:

Re1(λ)＝(nx1(λ)-ny1(λ))×d1

Where d1 represents the thickness of the first phase difference layer. A kind of electronic device

The optical film according to [ 1 ] or [ 2 ] above, wherein, for the second phase difference layer,

In the refractive index ellipsoid formed by the second phase difference layer, there is a relationship of nz2 (λ) > nx2 (λ) ≡ny2 (λ) in a range of wavelength λ=400 to 700nm,

[ In the formula, nz2 (λ) represents: in the refractive index ellipsoid formed by the second phase difference layer, the refractive index of light of wavelength λ (nm) in the direction perpendicular to the film plane. nx2 (λ) represents: in the refractive index ellipsoid formed by the second phase difference layer, the maximum refractive index for light of wavelength λ (nm) in the direction parallel to the film plane. ny2 (λ) represents: in the refractive index ellipsoid formed by the second phase difference layer, the refractive index of light having a wavelength λ (nm) in a direction parallel to the film plane and orthogonal to the direction of nx2 (λ) is obtained. Where nx2 (λ) =ny2 (λ), nx2 (λ) represents a refractive index in an arbitrary direction parallel to the film plane. A kind of electronic device

The second phase difference layer satisfies the following equations (5) and (6).

Rth2(450)/Rth2(550)≤1.00 (5)

1.00≤Rth2(650)/Rth2(550) (6)

[ Wherein Rth2 (450) represents a phase difference value in the thickness direction for light having a wavelength of λ=450 nm, rth2 (550) represents a phase difference value in the thickness direction for light having a wavelength of λ=550 nm, rth2 (650) represents a phase difference value in the thickness direction for light having a wavelength of 650nm, and Rth2 (λ) in the thickness direction for light having a wavelength of λ (nm), respectively, of the second phase difference layer is represented by the following formula:

Rth2(λ)＝[(nx2(λ)+ny2(λ))/2-nz2(λ)]×d2

Wherein, in the refractive index ellipsoid formed by the second phase difference layer, nz2 (λ) represents the principal refractive index in the direction perpendicular to the film plane at the wavelength λ (nm) ((nx 2 (λ) +ny2 (λ))/2) represents the average refractive index of the film plane at the wavelength λ (nm). d2 represents the thickness of the second phase difference layer. A kind of electronic device

The optical film according to any one of [1] to [ 3 ], wherein the first retardation layer further satisfies the relationship of the following formula (7).

120nm≤Re1(550)≤170nm (7)

In the expression, re1 (550) represents an in-plane phase difference value of the first phase difference layer with respect to light having a wavelength λ=550 nm. A kind of electronic device

The optical film according to any one of [ 1] to [4 ], wherein the second phase difference layer further has an optical characteristic represented by formula (8).

-100nm≤Rth2(550)≤-50nm (8)

[ Formula, rth2 (550) represents a phase difference value with respect to light having a wavelength of λ=550 nm in the thickness direction of the second phase difference layer. A kind of electronic device

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

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

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

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

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 polymerizing mainly the same polymerizable liquid crystal compound.

An elliptical polarizing plate with an optical compensation function, which has the optical film and the polarizing plate described in any one of [1 ] to [ 10 ].

The elliptical polarizing plate with an optical compensation function as described in [ 11 ], wherein the absorption axis of the polarizing plate and the slow axis of the first retardation layer have a relationship of 45.+ -. 5 DEG or 135.+ -. 5 DEG within the film plane, and the absorption axis of the polarizing plate and the slow axis of the first retardation layer are orthogonal to the slow axis of the second retardation layer in a direction perpendicular to the film plane.

The elliptical polarizing plate with an optical compensation function as described in [ 11 ] or [ 12 ], which is an optical laminate obtained by sequentially forming a polarizing plate, an adhesive layer, a first retardation layer, an adhesive layer, and a second retardation layer.

The elliptical polarizing plate with an optical compensation function as described in [ 11 ] or [ 12 ], which is an optical laminate obtained by sequentially forming a polarizing plate, an adhesive layer, a second retardation layer, an adhesive layer, and a first retardation layer.

An organic EL display device having the elliptical polarizing plate with an optical compensation function as described in any one of [ 11 ] to [ 14 ].

The method for producing an elliptical polarizing plate having an optical compensation function according to any one of the above [ 11 ] to [ 14 ], which comprises the following steps.

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

(step 1-B) a step of forming a second phase difference layer by applying a polymerizable liquid crystal compound to a substrate on which a vertical alignment film is formed and then polymerizing the substrate in a vertically aligned state; and

(Step 2) transferring and laminating the liquid crystal polymer of the first retardation layer and the liquid crystal polymer of the second retardation layer from the base material to the polarizing plate via the adhesive.

ADVANTAGEOUS EFFECTS OF INVENTION

The present invention provides a novel optical film in which light refractive index control is performed in three dimensions for all viewing directions and for visible light Quan Fan, and a method for manufacturing the same. Further, a liquid crystal display device and an organic EL display device capable of performing clear display by using the optical film are provided.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail. The scope of the present invention is not limited to the embodiments described herein, and various modifications may be made without departing from the spirit of the present invention.

The optical film of the present invention is formed of a first phase difference layer and a second phase difference layer. The first retardation layer and the second retardation layer may be formed by stretching or shrinking a polymer film, but from the viewpoint of thickness reduction, a film formed of a coating layer formed by coating a polymerizable liquid crystal (hereinafter, also referred to as a polymerizable liquid crystal compound) and polymerizing the polymer film in an aligned state is preferable.

In the first retardation layer and the second retardation layer, it is preferable that a composition containing a polymerizable liquid crystal compound (hereinafter, also referred to as a "composition for forming a retardation layer") is applied to a transparent substrate to form a layer, and the composition is heated and cooled to form a polymer in an oriented state of the polymerizable liquid crystal compound, from the viewpoints of thickness reduction and capability of arbitrarily designing wavelength dispersion characteristics. The composition for forming a retardation layer may further contain a solvent, a photopolymerization initiator, a photosensitizing agent, a polymerization inhibitor, a leveling agent (LEVELING AGENT), an adhesion improving agent, and the like, as described later.

The first retardation layer is preferably a liquid crystal cured film obtained by curing a polymerizable liquid crystal compound in a state of being oriented in a direction horizontal to the substrate surface, and the second retardation layer is preferably a liquid crystal cured film obtained by curing a polymerizable liquid crystal compound in a state of being oriented in a direction perpendicular to the substrate surface.

The first retardation layer preferably has an in-plane retardation Re1 (550) that satisfies the optical characteristics shown in the following formula (7) with respect to light having a wavelength of 550 nm. Further, it is preferable that the first retardation layer satisfies the optical characteristics shown in the formulas (3) and (4) with respect to the in-plane retardation Re1 (450) of light having a wavelength of 450nm, the in-plane retardation Re1 (550) of light having a wavelength of 550nm, and the in-plane retardation Re1 (650) of light having a wavelength of 650 nm. The first retardation layer preferably satisfies the optical characteristics represented by the following formulas (7), (3) and (4).

120nm≤Re1(550)≤170nm…(7)

(In the formula, re1 (550) represents the in-plane retardation value (in-plane retardation) of the first retardation layer with respect to light having a wavelength of 550 nm.)

Re1(450)/Re1(550)≤1.0…(3)

1.00≤Re1(650)/Re1(550)…(4)

(Wherein Re1 (450) represents the in-plane phase difference value of the first retardation layer to light having a wavelength of 450nm, re1 (550) represents the in-plane phase difference value of the first retardation layer to light having a wavelength of 550nm, re1 (650) represents the in-plane phase difference value of the first retardation layer to light having a wavelength of 650nm, respectively.)

When the in-plane phase difference value Re1 (550) of the first phase difference layer exceeds the range of formula (7), the following problem arises: when the optical film of the present invention is combined with a polarizing plate to form an elliptical polarizing plate with an optical compensation function, which will be described later, and attached to a mirror in this state, the front tone becomes red or blue. Further preferred ranges of in-plane phase difference values are: re1 (550) is less than or equal to 130nm and less than or equal to 160nm. When "Re1 (450)/Re 1 (550)" of the first retardation layer is larger than 1.0, light leakage on the short wavelength side in the elliptical polarizing plate having the retardation layer increases. Preferably from 0.75 to 0.92, more preferably from 0.77 to 0.87, and even more preferably from 0.79 to 0.85.

The in-plane phase difference value of the first phase difference layer may be adjusted by the thickness of the phase difference layer. Since the in-plane phase difference value is determined by the following formula (a), the three-dimensional refractive index and the film thickness d1 may be adjusted to obtain a desired in-plane phase difference value (Re 1 (λ): in-plane phase difference value of the first retardation layer at wavelength λ (nm)). The thickness of the retardation layer is preferably 0.5 μm to 5 μm, more preferably 1 μm to 3 μm. The thickness of the retardation layer can be measured by an interferometer, a laser microscope, or a stylus film thickness meter. The three-dimensional refractive index depends on the molecular structure and alignment state of a polymerizable liquid crystal compound described later.

Re1(λ)＝(nx1(λ)-ny1(λ))×d1 (A)

( In the formula, in the refractive index ellipsoid formed by the first retardation layer, there is a relationship of nx1 (λ) > ny1 (λ) ≡nz1 (λ), and nx1 (λ) represents: a principal refractive index for light of wavelength λ (nm) in a direction parallel to the film plane. ny1 (λ) represents: in the refractive index ellipsoid formed by the first retardation layer, the refractive index of light having a wavelength λ (nm) in a direction parallel to the film plane and orthogonal to the direction of nx1 (λ) is increased. d1 represents the thickness of the first retardation layer. The term "ny1 (λ) ≡nz1 (λ)", means that ny1 (λ) is substantially the same as nz1 (λ), and for example, it means that: the difference between the values is within 0.01 )

For the second phase difference layer, it is preferable that the phase difference value Rth2 (λ) for light having a wavelength λnm in the thickness direction satisfies the optical characteristic shown by the following formula (8). In addition, the optical characteristics represented by the following formulas (5) and (6) are also preferably satisfied. The second phase difference layer preferably satisfies the optical characteristics represented by the following formulas (8), (5) and (6).

-100nm≤Rth2(550)≤-50nm…(8)

(Wherein Rth2 (550) represents a phase difference value with respect to light having a wavelength of 550nm in the thickness direction.)

Rth2(450)/Rth2(550)≤1.0…(5)

1.00≤Rth2(650)/Rth2(550)…(6)

(Wherein Rth2 (450) represents a phase difference value in the thickness direction with respect to light having a wavelength of 450nm, rth2 (550) represents the same meaning as described above, and Rth2 (650) represents a phase difference value in the thickness direction with respect to light having a wavelength of 650 nm.)

When the phase difference value Rth2 (550) in the thickness direction of the second phase difference layer exceeds the range of formula (8), the following problems occur: when the optical film of the present invention is combined with a polarizing plate to form an elliptical polarizing plate with an optical compensation function, which will be described later, and attached to a mirror in this state, the oblique color tone changes to red or blue. The more preferable range of the phase difference value in the thickness direction is: rth2 (550) with the wavelength of-95 nm is less than or equal to-55 nm; further preferred ranges are: rth2 (550) is less than or equal to-90 nm and less than or equal to-60 nm. When "Rth2 (450)/Rth 2 (550)" of the second phase difference layer is larger than 1.0, light leakage on the short wavelength side in the elliptical polarizing plate having the phase difference layer increases. Preferably from 0.75 to 0.92, more preferably from 0.77 to 0.87, and even more preferably from 0.79 to 0.85.

The phase difference value in the thickness direction of the second phase difference layer may be adjusted by the thickness of the phase difference layer. Since the phase difference in the thickness direction is determined by the following formula (B), the three-dimensional refractive index and the film thickness d2 may be adjusted so as to obtain a desired phase difference in the thickness direction (Rth 2 (λ): a phase difference in the thickness direction of the second phase difference layer at the wavelength λ (nm)). The thickness of the retardation layer is preferably 0.2 μm to 5 μm, more preferably 0.5 μm to 2 μm. The thickness of the retardation layer can be measured by an interferometer, a laser microscope, or a stylus film thickness meter. The three-dimensional refractive index depends on the molecular structure and orientation of a polymerizable liquid crystal compound described later.

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

( In the formula, in the refractive index ellipsoid formed by the second phase difference layer, there is a relationship of nz2 (λ) > nx2 (λ) ≡ny2 (λ), where nz2 (λ) represents: in the refractive index ellipsoid formed by the second phase difference layer, the refractive index of light of wavelength λ (nm) in the direction perpendicular to the film plane. nx2 (λ) represents: in the refractive index ellipsoid formed by the second phase difference layer, the maximum refractive index for light of wavelength λ (nm) in the direction parallel to the film plane. ny2 (λ) represents: in the refractive index ellipsoid formed by the second phase difference layer, the refractive index of light having a wavelength λ (nm) in a direction parallel to the film plane and orthogonal to the direction of nx2 (λ) is obtained. Where nx2 (λ) =ny2 (λ), nx2 (λ) represents a refractive index in an arbitrary direction parallel to the film plane. Here, d2 represents the thickness of the second phase difference layer. The term "nx2 (λ) ≡ny2 (λ)", means that nx2 (λ) is substantially the same as ny2 (λ), and for example, it means that: the difference between the values is within 0.01 )

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

0.40≤Nz(450)≤0.60 (1)

0.40≤Nz(550)≤0.60 (2)

( Where Nz (λ) is an Nz coefficient showing a three-dimensional refractive index relationship with respect to light of wavelength λ (nm), and is represented by Nz (λ) = (nx (λ) -Nz (λ))/(nx (λ) -ny (λ)). nx (λ) represents: in an index ellipsoid formed by an optical film, the principal refractive index of light of wavelength λ (nm) in a direction parallel to the film plane. ny (λ) represents: in the refractive index ellipsoid formed by the optical film, the refractive index of light having a wavelength λ (nm) in a direction parallel to the film plane and orthogonal to the direction of nx (λ) is measured. nz (λ) represents: in an ellipsoid of refractive index formed by an optical film, the refractive index of light of wavelength λ (nm) in a direction perpendicular to the film plane. )

That is, the optical film of the present invention has a three-dimensional refractive index relationship of nx (λ) > nz (λ) > ny (λ), and the optical film has a relationship of formula (1) and formula (2), whereby excellent display characteristics can be imparted to color tone when mounted on a display. For Nz (λ), 0.45.ltoreq.nz (450.ltoreq.0.55 and 0.45.ltoreq.nz (550.ltoreq.0.55 are further preferable, respectively. Here, nz (450) represents an Nz coefficient at wavelength λ=450 nm, and Nz (550) represents an Nz coefficient at wavelength λ=550 nm, respectively.

The Nz coefficient (Nz coefficient: nz (λ)) (which represents the relationship of nx (λ), ny (λ), nz (λ) of the optical film at each wavelength λ (nm)) is calculated from the following formula.

Nz(λ)＝(nx(λ)-nz(λ))/(nx(λ)-ny(λ))

When the Nz coefficient of the optical film is calculated, if the front phase difference value and the thickness direction phase difference value of the first phase difference layer and the second phase difference layer are known, the calculation can be performed by the following formula (C).

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

(Wherein Re1 (λ) is the front phase difference value of the first phase difference layer at wavelength λ (nm), re2 (λ) is the front phase difference value of the second phase difference layer at wavelength λ (nm), rth1 (λ) is the phase difference value at wavelength λ (nm) in the thickness direction of the first phase difference layer, rth2 (λ) is the phase difference value at wavelength λ (nm) in the thickness direction of the second phase difference layer.)

[ Polymerizable liquid Crystal ]

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

The photopolymerizable functional group means a group that can participate in a polymerization reaction by a living radical, an acid, or the like generated by a photopolymerization initiator. Examples of the photopolymerizable functional group include vinyl, vinyloxy, 1-chlorovinyl, isopropenyl, 4-vinylphenyl, acryloyloxy, methacryloyloxy, oxetanyl, and oxetanyl. Among them, acryloyloxy, methacryloyloxy, vinyloxy, oxetanyl and oxetanyl groups are preferable, and acryloyloxy is more preferable. The liquid crystal may be a thermotropic liquid crystal or a lyotropic liquid crystal, but the thermotropic liquid crystal is preferable in view of being capable of performing strict film thickness control. The phase-ordered structure in the thermotropic liquid crystal may be a nematic liquid crystal or a smectic liquid crystal.

In the present invention, the polymerizable liquid crystal compound is particularly preferably represented by the following formula (I) in view of exhibiting the above-mentioned inverse wavelength dispersibility.

[ Chemical formula 1]

In the formula (I), ar represents a divalent aromatic group which may have a substituent. The aromatic group herein means a group having a planar and cyclic structure, and having pi electrons of the cyclic structure in a number of [4n+2] in accordance with the Skoter rule. Here, n represents an integer. In the case where a ring structure is formed by containing a heteroatom such as-n=, -S-, etc., the following is also included: the inclusion of non-covalent electron pairs on these heteroatoms satisfies the rule of shock and is aromatic. Preferably, the divalent aromatic group contains at least 1 or more of a nitrogen atom, an oxygen atom and a sulfur atom.

G ¹ and G ² each independently represent a divalent aromatic group or a divalent alicyclic hydrocarbon group. Here, the hydrogen atom contained in the divalent aromatic group or the divalent alicyclic hydrocarbon group may be substituted with a halogen atom, an alkyl group having 1 to 4 carbon atoms, a fluoroalkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a cyano group, or a nitro group, and the carbon atoms constituting the divalent aromatic group or the divalent alicyclic hydrocarbon group may be replaced with an oxygen atom, a sulfur atom, or a nitrogen atom.

L ¹、L²、B¹ and B ² are each independently a single bond or a divalent linking group.

K. l each independently represents an integer of 0 to 3, satisfying the relation 1.ltoreq.k+l. Here, when 2.ltoreq.k+l, B ¹ and B ²、G¹ and G ² may be the same or different from each other, respectively.

E ¹ and E ² each independently represent an alkanediyl group (alkanediyl) having 1 to 17 carbon atoms, wherein hydrogen atoms contained in the alkanediyl group may be substituted with halogen atoms, and-CH ₂ -contained in the alkanediyl group may be replaced with-O-, -S-, -Si-. P ¹ and P ² each independently represent a polymerizable group or a hydrogen atom, and at least 1 is a polymerizable group.

Each of G ¹ and G ² is independently preferably a1, 4-phenylene group (PHENYLENEDIYL) which may be substituted with at least 1 substituent selected from a halogen atom and an alkyl group having 1 to 4 carbon atoms, a1, 4-cyclohexanediyl group which may be substituted with at least 1 substituent selected from a halogen atom and an alkyl group having 1 to 4 carbon atoms, more preferably a1, 4-phenylene group substituted with a methyl group, an unsubstituted 1, 4-phenylene group, or an unsubstituted 1, 4-trans-cyclohexanediyl group, particularly preferably an unsubstituted 1, 4-phenylene group, or an unsubstituted 1, 4-trans-cyclohexanediyl group.

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

L ¹ and L ² are each independently preferably a single bond, an alkylene group 、-O-、-S-、-R^a1OR^a2-、-R^a3COOR^a4-、-R^a5OCOR^a6-、-R^a7OC＝OOR^a8-、-N＝N-、-CR^c＝CR^d-、 having 1 to 4 carbon atoms or-C.ident.C-. Here, R ^a1～R^a8 each independently represents a single bond or an alkylene group having 1 to 4 carbon atoms, and R ^c and R ^d represent an alkyl group having 1 to 4 carbon atoms or a hydrogen atom. L ¹ and L ² are each independently more preferably a single bond, -OR ^a2-1-、-CH₂-、-CH₂CH₂-、-COOR^a4-1 -, OR-OCOR ^a6-1 -. Here, R ^a2-1、R^a4-1、R^a6-1 each independently represents any one of a single bond, -CH ₂-、-CH₂CH₂ -. L ¹ and L ² are each independently further preferably a single bond, -O-, -CH ₂CH₂-、-COO-、-COOCH₂CH₂ -, or-OCO-.

B ¹ and B ² are each independently preferably a single bond, an alkylene group having 1 to 4 carbon atoms, a-O-, -S-, -R ^a9OR^a10-、-R^a11COOR^a12-、-R^a13OCOR^a14 -, or-R ^a15OC＝OOR^a16 -. Here, R ^a9～R^a16 each independently represents a single bond or an alkylene group having 1 to 4 carbon atoms. More preferably, each of B ¹ and B ² is independently a single bond, -OR ^a10-1-、-CH₂-、-CH₂CH₂-、-COOR^{a12 -1} -, OR-OCOR ^a14-1 -. Here, R ^a10-1、R^a12-1、R^a14-1 each independently represents any one of a single bond, -CH ₂-、-CH₂CH₂ -. B ¹ and B ² are each independently further preferably a single bond, -O-, -CH ₂CH₂-、-COO-、-COOCH₂CH₂ -, -OCO-, or-OCOCH ₂CH₂ -.

From the viewpoint of exhibiting inverse wavelength dispersibility, k and l are preferably in the range of 2.ltoreq.k+l.ltoreq.6, more preferably k+l=4, further preferably k=2 and l=2.

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

Examples of the polymerizable group represented by P ¹ or P ² include 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, an oxetanyl group, and an oxetanyl group.

Among them, acryloyloxy, methacryloyloxy, vinyloxy, oxetanyl and oxetanyl groups are preferable, and acryloyloxy is more preferable.

Ar preferably has at least one selected from the group consisting of an aromatic hydrocarbon ring which may have a substituent, an aromatic heterocyclic ring which may have a substituent, and an electron withdrawing group. Examples of the aromatic hydrocarbon ring include benzene ring, naphthalene ring, and anthracene ring, and benzene ring and naphthalene ring are preferable. Examples of the aromatic heterocyclic ring include a furan ring, a benzofuran ring, a pyrrole ring, an indole ring, a thiophene ring, a benzothiophene ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a triazole ring, a triazine ring, a pyrroline ring, an imidazole ring, a pyrazole ring, a thiazole ring, a benzothiazole ring, a thienothiazole ring, an oxazole ring, a benzoxazole ring, and a phenanthroline ring. Among them, a thiazole ring, a benzothiazole ring, or a benzofuran ring is preferable, and a benzothiazolyl group is more preferable. When a nitrogen atom is contained in Ar, the nitrogen atom preferably has pi electrons.

In the formula (I), the total number N _π of pi electrons included in the 2-valent aromatic group represented by Ar is preferably 8 or more, more preferably 10 or more, further preferably 14 or more, and particularly preferably 16 or more. The content is preferably 30 or less, more preferably 26 or less, and even more preferably 24 or less.

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

[ Chemical formula 2]

In the formulae (Ar-1) to (Ar-22), each of Z ⁰、Z¹ and Z ² independently represents a linking moiety, a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cyano group, a nitro group, an alkylsulfinyl group having 1 to 12 carbon atoms, an alkylsulfonyl group having 1 to 12 carbon atoms, a carboxyl group, a fluoroalkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkylthio group having 1 to 12 carbon atoms, an N-alkylamino group having 1 to 12 carbon atoms, an N, N-dialkylamino group having 2 to 12 carbon atoms, an N-alkylsulfonyl group having 1 to 12 carbon atoms, or an N, N-dialkylsulfamoyl group having 2 to 12 carbon atoms.

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

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

Y ¹、Y² and Y ³ each independently represent an aromatic hydrocarbon group or an aromatic heterocyclic group which may be substituted.

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 in Y ¹、Y² and Y ³ include aromatic hydrocarbon groups having 6 to 20 carbon atoms such as phenyl, naphthyl, anthryl, phenanthryl, and biphenyl, and preferably phenyl and naphthyl, and more preferably phenyl. Examples of the aromatic heterocyclic group include an aromatic heterocyclic group having 4 to 20 carbon atoms and containing at least 1 hetero atom (nitrogen atom, oxygen atom, sulfur atom, etc.), such as a furyl group, a pyrrolyl group, a thienyl group, a pyridyl group, a thiazolyl group, and a benzothiazolyl group, and a furyl group, a thienyl group, a pyridyl group, a thiazolyl group, and a benzothiazolyl group are preferable.

Y ¹、Y² and Y ³ each independently may be an optionally substituted polycyclic aromatic hydrocarbon group or a polycyclic aromatic heterocyclic group. Polycyclic aromatic hydrocarbon groups refer to condensed polycyclic aromatic hydrocarbon groups or groups derived from an aromatic ring set. Polycyclic aromatic heterocyclic groups refer to fused polycyclic aromatic heterocyclic groups, or groups derived from an aromatic ring set.

Z ⁰、Z¹ 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, Z ⁰ is more preferably a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or a cyano group, and Z ¹ and Z ² are more preferably a hydrogen atom, a fluorine atom, a chlorine atom, a methyl group, or a cyano group.

Q ¹ and Q ² are preferably-NH-, -S-, -NR ^2'-、-O-,R^2' are preferably hydrogen atoms. Wherein, S-, -O-, -NH-is particularly preferred.

Of the formulae (Ar-1) to (Ar-22), the formulae (Ar-6) and (Ar-7) are preferable from the viewpoint of stability of the molecule.

In the formulae (Ar-16) to (Ar-22), Y ¹ may form an aromatic heterocyclic group together with the nitrogen atom to which it is bonded and Z ⁰. Examples of the aromatic heterocyclic group include those described above as aromatic heterocyclic groups that Ar may have, and examples thereof include pyrrole rings, imidazole rings, pyrroline rings, pyridine rings, pyrazine rings, pyrimidine rings, indole rings, quinoline rings, isoquinoline rings, purine rings, pyrrolidine rings, and the like. The aromatic heterocyclic group may have a substituent. In addition, Y ¹ together with the nitrogen atom to which it is bonded and Z ⁰ may be the aforementioned polycyclic aromatic hydrocarbon group or polycyclic aromatic heterocyclic group which may be substituted. Examples thereof include a benzofuran ring, a benzothiazole ring, and a benzoxazole ring.

The total content of the polymerizable liquid crystal compounds in 100 parts by mass of the solid content of the composition for forming a phase difference 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 80 parts by mass to 94 parts by mass, and even more preferably 80 parts by mass to 90 parts by mass. When the total content is within the above range, the alignment property of the polymerizable liquid crystal compound in the obtained retardation layer tends to be improved. The solid content herein refers to the total amount of components obtained by removing the solvent from the composition.

[ Solvent ]

The solvent is preferably a solvent in which the polymerizable liquid crystal compound is soluble, and is preferably a solvent inert to the polymerization reaction of the polymerizable liquid crystal compound.

Examples of the solvent include alcohol solvents such as water, methanol, ethanol, ethylene glycol, isopropanol, 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; amide solvents such as dimethylacetamide, dimethylformamide, N-methyl-2-pyrrolidone, and 1, 3-dimethyl-2-imidazolidinone. These solvents may be used alone in an amount of 1, or may be used in an amount of 2 or more. Among them, alcohol solvents, ester solvents, ketone solvents, chlorine-containing solvents, amide solvents, and aromatic hydrocarbon solvents are preferable.

The content of the solvent in 100 parts by mass of the composition is preferably 50 to 98 parts by mass, more preferably 70 to 95 parts by mass. Therefore, the content of the solid content in 100 parts by mass of the composition is preferably 2 parts by mass to 50 parts by mass. When the solid content of the composition is 50 parts by mass or less, the viscosity of the composition is lowered, and thus the thickness of the retardation layer becomes substantially uniform, and unevenness tends not to occur in the retardation layer. The solid content may be appropriately determined in consideration of the thickness of the retardation layer to be produced.

< Polymerization initiator >

The polymerization initiator is a compound which can generate a reactive species by heat or light to initiate polymerization of a polymerizable liquid crystal or the like. Examples of the reactive species include reactive species such as a radical, a cation, and an anion. Among them, a photopolymerization initiator that generates radicals by light irradiation is preferable from the viewpoint of easy control of the reaction.

Examples of the photopolymerization initiator include benzoin compounds, benzophenone compounds, benzil ketal compounds, α -hydroxyketone compounds, α -aminoketone compounds, triazine compounds, iodonium salts, and sulfonium salts. Specifically, irgacure (registered trademark )907、Irgacure184、Irgacure651、Irgacure819、Irgacure250、Irgacure369、Irgacure379、Irgacure127、Irgacure2959、Irgacure754、Irgacure379EG( or more is manufactured by BASF Japan Co., ltd.), SEIKUOL BZ, SEIKUOL Z, SEIKUOL BEE (manufactured by Seikovia chemical Co., ltd.), kayacure (manufactured by Koehne Japan Co., ltd.), kayacure UVI-6992 (manufactured by DOW Chemical Company, )、ADEKA OPTOMER SP-152、ADEKA OPTOMER SP-170、ADEKA OPTOMER N-1717、ADEKA OPTOMER N-1919、ADEKA ARKLS NCI-831、ADEKA ARKLS NCI-930( or more is manufactured by ADEKA Co., ltd.), TAZ-A, TAZ-PP (manufactured by Siber Hegner Co., ltd.) and TAZ-104 (manufactured by SANWA CHEMICAL Co., ltd.).

The composition for forming a retardation layer contains at least 1 photopolymerization initiator, preferably 1 or 2 photopolymerization initiators.

The photopolymerization initiator is preferably 300 to 400nm, more preferably 300 to 380nm in maximum absorption wavelength, and among them, an α -acetophenone type polymerization initiator and an oxime type photopolymerization initiator are preferable in order to make full use of energy emitted from a light source and to make productivity excellent.

Examples of the α -acetophenone compound include 2-methyl-2-morpholino (morpholino) -1- (4-methylsulfanyl phenyl (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, and more preferably 2-methyl-2-morpholino-1- (4-methylsulfanyl phenyl) propan-1-one and 2-dimethylamino-1- (4-morpholinophenyl) -2-benzylbutan-1-one. Examples of commercial products of the α -acetophenone compound include Irgacure369, 379EG, 907 (from BASF Japan, inc., above) and SEIKUOL BEE (from the company of fine chemistry).

The oxime-type photopolymerization initiator generates methyl radicals by irradiation with light. By the action of the methyl radical, the polymerization of the polymerizable liquid crystal compound in the deep portion of the retardation layer is suitably performed. Further, from the viewpoint of more efficiently performing the polymerization reaction in the deep portion of the retardation layer, it is preferable to use a photopolymerization initiator capable of efficiently utilizing ultraviolet rays having a wavelength of 350nm or more. As the photopolymerization initiator capable of efficiently utilizing ultraviolet rays having a wavelength of 350nm or more, a triazine compound and an oxime ester carbazole compound are preferable, and an oxime ester carbazole compound is more preferable from the viewpoint of sensitivity. Examples of the oxime ester-type carbazole compound include 1, 2-octanedione-1- [4- (phenylthio) -2- (O-benzoyl oxime) ] (1, 2-octanedione,1- [4- (phenylthio) -2- (O-benzoyloxime) ]), 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl ] ethanone 1- (O-acetyl oxime) (ethanone, 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl ] -1- (O-acetyloxime)), and the like. As the oxime ester type carbazole compounds are commercially available products, irgacureOXE-01, irgacureOXE-02, irgacureOXE-03 (manufactured by BASF Japan Co., ltd.), ADEKA OPTOMER N-1919, ADEKA ARKLS NCI-831 (manufactured by ADEKA Co., ltd.), and the like.

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

By compounding a polymerization inhibitor, the polymerization reaction of the polymerizable liquid crystal compound can be controlled. Examples of the polymerization inhibitor include hydroquinone and hydroquinone having a substituent such as an alkyl ether group; catechols having a substituent such as an alkyl ether group, such as butyl catechol; pyrogallol; radical scavenger such as 2, 6-tetramethylpiperidine-1-oxyl radical; thiophenols; beta-naphthylamines and beta-naphthols. The content of the polymerization inhibitor is usually 0.01 to 10 parts by mass, preferably 0.1 to 5 parts by mass, and more preferably 0.1 to 3 parts by mass, per 100 parts by mass of the polymerizable liquid crystal compound, in order to polymerize the polymerizable liquid crystal compound without disturbing the alignment of the polymerizable liquid crystal compound.

In addition, the use of a sensitizer can increase the sensitivity of the photopolymerization initiator. Examples of the photosensitizing agent include xanthones such as xanthone and thioxanthone; anthracene and anthracene having a substituent such as an alkyl ether group; phenothiazine; rubrene. The content of the photosensitizing agent is usually 0.01 to 10 parts by mass, preferably 0.05 to 5 parts by mass, and more preferably 0.1 to 3 parts by mass, relative to 100 parts by mass of the polymerizable liquid crystal compound.

[ Leveling agent ]

The leveling agent is an additive having a function of adjusting the fluidity of the composition and flattening a film obtained by coating the composition, and examples thereof include silicone-based, polyacrylate-based, and perfluoroalkyl-based leveling agents such as silane coupling agents. Specifically, examples thereof include DC3PA, SH7PA, DC11PA, SH28PA, SH29PA, SH30PA, ST80PA, ST86PA, SH8400, SH8700, FZ2123 (each of which is Dow Corning Toray Co., ltd., manufactured by the chemical industry 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( or more), TSF400, TSF401, TSF410, TSF4300, TSF4440, TSF4445, TSF-4446, TSF4452, TSF4460 (each of which is Momentive Performance Materials Japan LLC), fluorinert FC-72, fluorinert FC-40, fluorinert FC-43, fluorinert FC-3283 (each of which is Sumitomo 3M, ltd.), MEGAFACE (each of which is DIC, each of which is registered trademark) )R-08、MEGAFACE R-30、MEGAFACE R-90、MEGAFACE F-410、MEGAFACE F-411、MEGAFACE F-443、MEGAFACE F-445、MEGAFACE F-470、MEGAFACE F-477、MEGAFACE F-479、MEGAFACE F-482、MEGAFACE F-483( or more), fluorinert FC-40, fluorinert FC-43, fluorinert FC-3283 (each of which is Sumitomo 3M, ltd., MEGAFACE (each of which is DIC, each of which is shown by the trade name) and Fluorind., TK. ltd., ltd.) of the above-described materials, surflon (registered trademark) S-381, surflon S-382, surflon S-383, surflon S-393, surflon SC-101, surflon SC-105, KH-40, SA-100 (all of AGC SEIMI CHEMICAL Co., ltd.) of the above-described materials, trade name E1830, trade name E5844 (DAIKIN FINE CHEMICAL Laboratory Co., ltd.) of the above-described materials, BM-1000, BM-1100, BYK-352, BYK-353, and BYK-361N (all trade names, manufactured by BM Chemie corporation) and the like.

The content of the leveling agent in the composition for forming a retardation layer is preferably 0.01 to 5 parts by mass, more preferably 0.05 to 3 parts by mass, based on 100 parts by mass of the polymerizable liquid crystal compound. When the content of the leveling agent is within the above range, it is preferable because it is easy to horizontally orient the polymerizable liquid crystal compound and the obtained retardation layer tends to be smoother. The composition for forming a retardation layer may contain 2 or more leveling agents.

[ Substrate ]

As the substrate, a glass substrate and a film substrate are exemplified, and from the viewpoint of processability, a film substrate is preferable, and from the viewpoint of continuous production, a roll film having a long dimension is more preferable. Examples of the resin constituting the film base material include polyolefin such as polyethylene, polypropylene, and norbornene polymer; a cyclic olefin resin; polyvinyl alcohol; polyethylene terephthalate; a polymethacrylate; a polyacrylate; cellulose esters such as triacetyl cellulose, diacetyl cellulose, and cellulose acetate propionate (cellulose acetate propionate); polyethylene naphthalate; a polycarbonate; polysulfone; polyether sulfone; polyether ketone; polyphenylene sulfide, polyphenylene oxide, and other plastics.

Examples of the commercially available cellulose ester substrate include "Fujitac Film" (manufactured by Fuji Photo Film co., ltd.); "KC8UX2M", "KC8UY" and "KC4UY" (manufactured by Konica Minolta Opto Co., ltd.) are mentioned.

Examples of commercially available cycloolefin resins include "Topas" (registered trademark) (manufactured by Ticona corporation (germany)), "ARTON" (registered trademark) (manufactured by JSR corporation), "ZEONOR" (registered trademark), and "ZEONEX" (registered trademark) (manufactured by ZEONEX corporation) and "APEL" (registered trademark) (manufactured by mitsunk chemical corporation). Such a cycloolefin resin can be formed into a film as a base material by known means such as a solvent casting method and a melt extrusion method. Commercially available cycloolefin resin base materials can also be used. Examples of commercially available cycloolefin resin substrates include "ESCENA" (registered trademark), "SCA40" (registered trademark) (the above are available from Seattle chemical Co., ltd.), and "ZEONOR FILM" (registered trademark) (available from OPTES Co., ltd.) and "ARTON FILM" (registered trademark) (available from JSR Co., ltd.).

The thickness of the base material is preferably thin in terms of quality to such an extent that practical handling is possible, but if too thin, strength is lowered and workability tends to be poor. The thickness of the substrate is usually 5 μm to 300. Mu.m, preferably 20 μm to 200. Mu.m. Further, the effect of further thinning can be obtained by peeling the base material and transferring only the polymer in a state where the polymerizable liquid crystal compound is aligned.

[ Alignment film ]

The alignment film is preferably formed on the surface of the substrate to which the composition for forming a retardation layer is to be applied. The alignment film is a film having an alignment control force for aligning the polymerizable liquid crystal compound in a desired direction.

The alignment film is preferably one having solvent resistance (not being dissolved by application of the composition for forming a retardation layer, etc.), and heat resistance (being resistant to heat treatment for removing the solvent or aligning a polymerizable liquid crystal compound described later).

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

As the alignment film forming the first retardation layer, an alignment film exhibiting an alignment control force in the horizontal direction can be 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 film, a photo-alignment film is preferable in that the alignment direction can be easily controlled.

In the rubbing alignment film, an alignment polymer can be used. Examples of the alignment polymer include polyamide having an amide bond, gelatin, polyimide having an imide bond, and hydrolyzed polyamide acid, polyvinyl alcohol, alkyl-modified polyvinyl alcohol, polyacrylamide, polyoxazole, polyethylenimine, polystyrene, polyvinylpyrrolidone, polyacrylic acid, and polyacrylate. More than 2 kinds of oriented polymers may be combined.

In general, a composition obtained by dissolving an alignment polymer in a solvent (hereinafter, also referred to as an alignment polymer composition) is applied to a substrate, the solvent is removed to form a coating film, and the coating film is rubbed, whereby an alignment control force can be applied.

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

Oriented polymer compositions are commercially available. Examples of commercially available oriented polymer compositions include SUNEVER (registered trademark, manufactured by Nissan chemical industries, ltd.), OPTMER (registered trademark, manufactured by JSR, ltd.).

As a method of applying the alignment polymer composition to the substrate, there can be mentioned the same method as the method of applying the composition for forming a phase difference layer to the substrate described later. Examples of the method for removing the solvent contained in the oriented polymer composition include a natural drying method, a pneumatic drying method, a heat drying method, and a vacuum drying method.

As a method of the rubbing treatment, for example, a method of bringing a rotating rubbing roller around which a rubbing cloth is wound into contact with the coating film is mentioned. When masking (masking) is performed during the rubbing treatment, a plurality of regions (patterns) having different alignment directions may be formed on the alignment film.

The photo-alignment film is generally obtained by applying a composition for forming a photo-alignment film 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 light). The photo-alignment film can arbitrarily control the direction of the alignment control force by selecting the polarization direction of the irradiated polarized light.

The photoreactive group is a group that generates orientation ability by irradiation with light. Specifically, a group that participates in a photoreaction that causes an orientation ability such as an orientation induction reaction, an isomerization reaction, a photodimerization reaction, a photocrosslinking reaction, or a photodecomposition reaction of a molecule that occurs by light irradiation is exemplified. The photoreactive group is preferably a group having an unsaturated bond, particularly a double bond, and particularly preferably a group having at least one selected from the group consisting of 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 carbon-oxygen double bond (c=o bond).

Examples of the photoreactive group having a c=c bond include a vinyl group, a polyalkenyl group, a stilbene azolyl group (stilbazole group), a stilbene azolium group (stilbazolium group), a chalcone group, and a cinnamoyl group. Examples of the photoreactive group having a c=n bond include a group having a structure such as an aromatic schiff base or an aromatic hydrazone. Examples of the photoreactive group having an n=n bond include an azobenzene group, an azonaphthalene group, an aromatic heterocyclic azo group, a disazo group, a formazan (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 substituents such as alkyl, alkoxy, aryl, allyloxy, cyano, alkoxycarbonyl, hydroxyl, sulfonic acid, haloalkyl, and the like.

From the viewpoint of excellent orientation, a group participating in a photodimerization reaction or a photocrosslinking reaction is preferable. Among them, the photoreactive group involved in the photopolymerization reaction is preferable, and cinnamoyl and chalcone groups are preferable in terms of the light irradiation amount of the polarized light required for alignment is small and a photoalignment film excellent in thermal stability and temporal stability is easily obtained. The polymer having a photoreactive group is particularly preferably a polymer having a cinnamoyl group, such as a polymer having a cinnamic acid structure or a cinnamic acid ester structure at the terminal of a side chain.

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

As a method of applying the composition for forming a photo-alignment film to a substrate, there can be mentioned the same method as the method of applying the composition for forming a phase difference layer to a substrate described later. As a method for removing the solvent from the composition for forming a coated photo-alignment film, the same method as that for removing the solvent from the alignment polymer composition can be mentioned.

In the case of irradiating polarized light, the polarized light may be directly irradiated to a product obtained by removing the solvent from the composition for forming a photo-alignment film applied to the substrate, or may be irradiated by irradiating polarized light from the substrate side and transmitting the polarized light through the substrate. The polarized light is preferably substantially parallel light. The wavelength of the irradiated polarized light is preferably a wavelength in a wavelength region where the photoreactive group of the polymer or monomer having the photoreactive group can absorb light energy. Specifically, UV (ultraviolet) having a wavelength in the range of 250nm to 400nm is particularly preferable. Examples of the light source for irradiating the polarized light include ultraviolet light laser such as xenon lamp, high-pressure mercury lamp, ultra-high-pressure mercury lamp, metal halide lamp, krF, arF, and the like. Among them, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, and a metal halide lamp are preferable because of their high emission intensity of ultraviolet rays having a wavelength of 313 nm. The polarized UV light can be irradiated by transmitting the light emitted from the light source through an appropriate polarizing element to irradiate the light. Examples of the polarizing element include a polarizing filter, a polarizing prism such as a gram-thompson polarizing prism and a gram-taylor polarizing prism, and a wire grid. Among them, a wire grid type polarizing element is preferable from the viewpoints of an increase in area and resistance to heat.

In the case of performing polarized light irradiation, a plurality of regions (patterns) having different directions of alignment of the liquid crystal may be formed by masking.

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

As a method for obtaining the groove alignment film, the following methods are mentioned: a method of forming a concave-convex pattern by exposing the surface of a photosensitive polyimide film through an exposure mask having a slit with a pattern shape, and then performing development and rinsing treatment; a method of forming a layer of UV curable resin before curing on a plate-like master having grooves on the surface thereof, and curing the resin layer after transferring it to a substrate; and a method in which a roll master having a plurality of grooves is pressed against a film of a UV curable resin before curing formed on a substrate to form irregularities, and then cured; etc.

The thickness of the alignment film for forming the first retardation layer is usually in the range of 10 to 10000nm, preferably 10 to 1000nm, and more preferably 50 to 500 nm.

As the alignment film forming the second phase difference layer, an alignment film having an alignment control force in the vertical direction (hereinafter, also referred to as a vertical alignment film) can be applied. As the vertical alignment film, a material that reduces the surface tension of the substrate surface is preferably used. Examples of such a material include the aforementioned oriented polymer, fluorine-based polymer such as perfluoroalkyl group, polyimide compound, silane compound, and polysiloxane compound obtained by condensation reaction of these. From the viewpoint of easily lowering the surface tension, the silane compound is preferable.

Examples of suitable silane compounds include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-glycidoxypropyl trimethoxysilane, 3-glycidoxypropyl methyldimethoxysilane, 2- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, 3-methacryloxypropyl trimethoxysilane, 3-mercaptopropyl trimethoxysilane, 3-glycidoxypropyl triethoxysilane, 3-glycidoxypropyl dimethoxymethylsilane, 3-glycidoxypropyl ethoxydimethylsilane, and the like. More than 2 silane compounds may be used.

The silane compound may be an organosilicon monomer type silane compound, or an organosilicon oligomer (polymer) type silane compound. When the silicone oligomer is represented by a (monomer) - (monomer) copolymer, the following can be mentioned, for example.

Mercaptopropyl-containing copolymers such as 3-mercaptopropyl trimethoxysilane-tetramethoxysilane copolymer, 3-mercaptopropyl trimethoxysilane-tetraethoxysilane copolymer, 3-mercaptopropyl triethoxysilane-tetramethoxysilane copolymer, and 3-mercaptopropyl triethoxysilane-tetraethoxysilane copolymer;

Mercaptomethyl trimethoxysilane-tetramethoxysilane copolymer, mercaptomethyl trimethoxysilane-tetraethoxysilane copolymer, mercaptomethyl triethoxysilane-tetramethoxysilane copolymer, mercaptomethyl triethoxysilane-tetraethoxysilane copolymer and the like, and having a mercaptomethyl group;

Methacryloxypropyl trimethoxysilane-tetramethoxysilane copolymer, 3-methacryloxypropyl trimethoxysilane-tetraethoxysilane copolymer, 3-methacryloxypropyl triethoxysilane-tetramethoxysilane copolymer, 3-methacryloxypropyl triethoxysilane-tetraethoxysilane copolymer, 3-methacryloxypropyl methyldimethoxysilane-tetramethoxysilane copolymer, 3-methacryloxypropyl methyldimethoxysilane-tetraethoxysilane copolymer, 3-methacryloxypropyl methyldiethoxysilane-tetramethoxysilane copolymer, 3-methacryloxypropyl methyldiethoxysilane-tetraethoxysilane copolymer, or the like, containing methacryloxypropyl groups;

Acryloxypropyl-containing copolymers such as 3-acryloxypropyl trimethoxysilane-tetramethoxysilane copolymer, 3-acryloxypropyl trimethoxysilane-tetraethoxysilane copolymer, 3-acryloxypropyl triethoxysilane-tetramethoxysilane copolymer, 3-acryloxypropyl triethoxysilane-tetraethoxysilane copolymer, 3-acryloxypropyl methyldimethoxysilane-tetramethoxysilane copolymer, 3-acryloxypropyl methyldimethoxysilane-tetraethoxysilane copolymer, 3-acryloxypropyl methyldiethoxysilane-tetramethoxysilane copolymer, and 3-acryloxypropyl methyldiethoxysilane-tetraethoxysilane copolymer;

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

And amino group-containing copolymers such as 3-aminopropyl trimethoxysilane-tetramethoxysilane copolymer, 3-aminopropyl trimethoxysilane-tetraethoxysilane copolymer, 3-aminopropyl triethoxysilane-tetramethoxysilane copolymer, 3-aminopropyl methyldimethoxysilane-tetraethoxysilane copolymer, 3-aminopropyl methyldiethoxysilane-tetramethoxysilane copolymer, and 3-aminopropyl methyldiethoxysilane-tetraethoxysilane copolymer.

Among them, a silane compound having an alkyl group at the molecular terminal is preferable, and a silane compound having an alkyl group having 6 to 20 carbon atoms is more preferable. These silane compounds are often liquid and therefore can be applied directly to a substrate or can be applied to a substrate after being dissolved in a solvent. In addition, the adhesive may be applied to a substrate after being dissolved in a solvent together with various polymers.

As a method of applying the vertical alignment film to the substrate, there is mentioned the same method as the method of applying the composition for forming a phase difference layer to the substrate described later. As a method for removing the solvent from the composition for forming a coated photo-alignment film, the same method as that for removing the solvent from the alignment polymer composition can be mentioned.

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

Method for producing retardation layer

< Coating of composition for Forming phase-difference layer >

The retardation layer can be formed by applying the composition for forming a retardation layer to the substrate or the alignment film. Examples of the method of applying the composition for forming a retardation layer to a substrate include extrusion coating, direct gravure coating, reverse gravure coating, CAP coating, slit coating, micro gravure coating, die coating, and ink jet coating. Further, a method of coating using a coater such as a dip coater, a bar coater, or a spin coater is also included. Among them, in the case of continuous coating by Roll-to-Roll (Roll to Roll), a coating method using a micro gravure method, an inkjet method, a slit coating method, or a die coating method is preferable, and in the case of coating on a monolithic substrate such as glass, a spin coating method with high uniformity is preferable.

< Drying of composition for Forming phase-difference layer >

Examples of the drying method for removing the solvent contained in the phase difference layer-forming composition include natural drying, air drying, heat drying, and vacuum drying, and a method of combining these. Among them, natural drying or heat drying is preferable. The drying temperature is preferably in the range of 0 to 200 ℃, more preferably in the range of 20 to 150 ℃, and even more preferably in the range of 50 to 130 ℃. The drying time is preferably 10 seconds to 20 minutes, more preferably 30 seconds to 10 minutes. The composition for forming a photo-alignment film and the alignment polymer composition may be dried in the same manner.

< Polymerization of polymerizable liquid Crystal Compound >

As a method of polymerizing the polymerizable liquid crystal compound, photopolymerization is preferable. The photopolymerization may be performed by irradiating a laminate obtained by applying a composition for forming a retardation layer containing a polymerizable liquid crystal compound onto a substrate or an alignment film with active energy rays. The active energy ray to be irradiated may be appropriately selected depending on the type of the polymerizable liquid crystal compound (particularly, the type of the photopolymerizable functional group contained in the polymerizable liquid crystal compound) contained in the dried film, the type of the photopolymerization initiator in the case of containing the photopolymerization initiator, and the amount thereof. Specifically, one or more light selected from the group consisting of visible light, ultraviolet light, infrared light, X-rays, α -rays, β -rays, and γ -rays may be used. Among them, ultraviolet light is preferable from the viewpoint of easy control of the progress of polymerization reaction and the viewpoint of availability of photopolymerization devices widely used in the art, and the type of polymerizable liquid crystal compound is preferably selected so that photopolymerization can be performed by ultraviolet light.

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

The intensity of the ultraviolet irradiation is usually 10mW/cm ²～3,000mW/cm². The ultraviolet irradiation intensity is preferably an intensity in a wavelength region effective for activation of the cationic polymerization initiator or the radical polymerization initiator. The time for irradiation of light is usually 0.1 seconds to 10 minutes, preferably 0.1 seconds to 5 minutes, more preferably 0.1 seconds to 3 minutes, and still more preferably 0.1 seconds to 1 minute. When irradiated 1 or more times with such ultraviolet irradiation intensity, the cumulative light amount thereof is 10mJ/cm ²～3,000mJ/cm², preferably 50mJ/cm ²～2,000mJ/cm², more preferably 100mJ/cm ²～1,000mJ/cm². When the cumulative light amount is less than the above range, curing of the polymerizable liquid crystal compound may become insufficient, and good transferability may not be obtained. Conversely, when the cumulative light amount is equal to or more than the above range, the optical film including the retardation layer may be colored.

[ Polarizing plate ]

The elliptical polarizing plate of the present invention is configured to include a polarizing plate and the optical film of the present invention, and for example, the polarizing plate and the optical film of the present invention can be bonded to each other with an adhesive or an adhesive layer or the like interposed therebetween, thereby obtaining the elliptical polarizing plate of the present invention.

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

The polarizing plate is formed of a polarizer having a polarizing function. Examples of the polarizer include a stretched film having a dye having absorption anisotropy adsorbed thereon, and a film obtained by coating a dye having absorption anisotropy and orienting the same. Examples of the dye having absorption anisotropy include dichroic dyes.

The stretched film having adsorbed thereon the dye having absorption anisotropy can be generally produced by the following steps: a step of uniaxially stretching a polyvinyl alcohol resin film; a step of dyeing a polyvinyl alcohol resin film with a dichroic dye to adsorb the dichroic dye; a step of treating the polyvinyl alcohol resin film having the dichromatic pigment adsorbed thereto with an aqueous boric acid solution; and a step of washing with water after the treatment with the aqueous boric acid solution. The polarizing plate obtained in the above manner is bonded to the transparent protective film, whereby a polarizing plate can be obtained. Examples of the dichroic dye include iodine and dichroic organic dyes. Examples of the dichroic organic dye include: a dichroic direct dye containing a disazo compound such as c.i. direct red (DIRECT RED) 39, a dichroic direct dye containing a compound such as trisazo or tetraazo, and the like. The thickness of the polarizer obtained by uniaxially stretching the polyvinyl alcohol resin film, dyeing with a dichroic dye, boric acid treatment, washing with water, and drying as described above is preferably 5 μm to 40 μm.

[ Adhesive ]

Examples of the adhesive used for bonding the polarizing plate to the optical film of the present invention or bonding the optical film of the present invention to the display device include a pressure-sensitive adhesive, a dry-curable adhesive, and a chemically reactive adhesive. Examples of the chemically reactive adhesive include active energy ray-curable adhesives. The adhesive layer formed of a pressure-sensitive adhesive, a dry-curable adhesive, or an active energy ray-curable adhesive is preferable as the adhesive between the polarizing plate and the optical film of the present invention, and the pressure-sensitive adhesive or the active energy ray-curable adhesive is preferable as the adhesive between the optical film of the present invention and the display device.

The pressure sensitive adhesive typically comprises a polymer and may also comprise a solvent.

Examples of the polymer include an acrylic polymer, a silicone polymer, a polyester, a polyurethane, and a polyether. Among them, an acrylic adhesive containing an acrylic polymer is preferable because it is excellent in optical transparency, has moderate wettability and cohesion, is excellent in adhesion, is excellent in weather resistance and heat resistance, and is less likely to cause lifting and peeling under heating or humidifying conditions.

The acrylic polymer is preferably a copolymer of (meth) acrylic acid ester 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, acrylic acid ester and methacrylic acid ester may be collectively referred to as (meth) acrylic acid ester, acrylic acid and methacrylic acid may be collectively referred to as (meth) acrylic acid), and a (meth) acrylic monomer having a functional group such as hydroxyethyl (meth) acrylate.

The pressure-sensitive adhesive containing such a copolymer is excellent in adhesion, and is preferably removed relatively easily because it does not cause adhesive residue or the like on the display device even when it is removed after being attached to the display device. The glass transition temperature of the acrylic polymer is preferably 25℃or lower, more preferably 0℃or lower. The mass average molecular weight of such an acrylic polymer is preferably 10 ten thousand or more.

Examples of the solvent include the solvents listed above as solvents. The pressure sensitive adhesive may contain a light diffusing agent. The light diffusing agent is an additive that imparts light diffusibility to the binder, and may be any fine particles having a refractive index different from that of the polymer contained in the binder. Examples of the light diffusing agent include fine particles made of an inorganic compound and fine particles made of an organic compound (polymer). Since a polymer contained in a binder as an active ingredient, including an acrylic polymer, generally has a refractive index of about 1.4 to 1.6, it is preferable to appropriately select a light diffusing agent having a refractive index of 1.2 to 1.8. The difference between the refractive index of the polymer contained in the binder as an active ingredient and the refractive index of the light diffusing agent is usually 0.01 or more, and is preferably 0.01 to 0.2 from the viewpoints of the brightness and the display property of the display device. The fine particles used as the light diffusing agent are preferably spherical and nearly monodisperse fine particles, and more preferably fine particles having an average particle diameter of 2 μm to 6 μm. The refractive index can be measured using a conventional minimum deflection angle method or an Abbe refractometer.

Examples of the fine particles formed of an inorganic compound include alumina (refractive index 1.76) and silica (refractive index 1.45). Examples of the fine particles formed of the organic compound (polymer) include melamine beads (refractive index 1.57), polymethyl methacrylate beads (refractive index 1.49), methyl methacrylate/styrene copolymer resin beads (refractive index 1.50 to 1.59), polycarbonate beads (refractive index 1.55), polyethylene beads (refractive index 1.53), polystyrene beads (refractive index 1.6), polyvinyl chloride beads (refractive index 1.46), and silicone beads (refractive index 1.46). The content of the light diffusing agent is usually 3 to 30 parts by mass relative to 100 parts by mass of the polymer.

The thickness of the pressure-sensitive adhesive may be determined according to its adhesion force and the like, and is thus not particularly limited, and is usually 1 μm to 40 μm. The thickness is preferably 3 μm to 25 μm, more preferably 5 μm to 20 μm, from the viewpoints of workability, durability, and the like. By setting the thickness of the adhesive layer formed of the adhesive to 5 μm to 20 μm, the brightness in the case of viewing the display device from the front and in the case of viewing the display device from an oblique direction can be maintained, and the stain and blurring of the display image are less likely to occur.

[ Dry curable adhesive ]

The dry curable adhesive may contain a solvent.

Examples of the dry curable adhesive include a composition containing a polymer of a monomer having a proton functional group such as a hydroxyl group, a carboxyl group or an amino group and an ethylenically unsaturated group, or a polyurethane resin as a main component, and further containing a crosslinking agent or a curable compound such as a polyaldehyde, an epoxy compound, an epoxy resin, a melamine compound, a zirconia compound, and a zinc compound. Examples of the polymer of the monomer having a proton functional group such as a hydroxyl group, a carboxyl group or an amino group and an ethylenically unsaturated group include ethylene-maleic acid copolymer, itaconic acid copolymer, acrylic acid copolymer, acrylamide copolymer, saponified product of polyvinyl acetate, and polyvinyl alcohol resin.

Examples of the polyvinyl alcohol resin include polyvinyl alcohol, partially saponified polyvinyl alcohol, fully saponified polyvinyl alcohol, carboxyl-modified polyvinyl alcohol, acetoacetyl-modified polyvinyl alcohol, hydroxymethyl-modified polyvinyl alcohol, amino-modified polyvinyl alcohol, and the like. The content of the polyvinyl alcohol resin in the aqueous binder is usually 1 to 10 parts by mass, preferably 1 to 5 parts by mass, per 100 parts by mass of water.

Examples of the polyurethane resin include polyester-based ionomer polyurethane resins.

The polyester-based ionomer polyurethane resin herein refers to a polyurethane resin having a polyester skeleton and having a small amount of an ionic component (hydrophilic component) introduced therein. The ionomer polyurethane resin is emulsified in water without using an emulsifier to form an emulsion, and thus an aqueous adhesive can be produced. In the case of using a polyester-based ionomer polyurethane resin, it is effective to blend a water-soluble epoxy compound as a crosslinking agent.

Examples of the epoxy resin include a polyamide epoxy resin obtained by reacting a polyamide polyamine (polyamidepolyamine) (which is obtained by reacting a polyalkylene polyamine (polyalkylene polyamine) such as diethylenetriamine or triethylenetetramine with a dicarboxylic acid such as adipic acid) with epichlorohydrin. Examples of the commercial products of the polyamide epoxy resin include "SUMIREZRESIN (registered trademark) 650" and "SUMIREZRESIN675" (Sumika Chemtex Co., ltd., "WS-525" (manufactured by Japanese PMC Co., ltd.). When the epoxy resin is blended, the amount of the epoxy resin is usually 1 to 100 parts by mass, preferably 1 to 50 parts by mass, based on 100 parts by mass of the polyvinyl alcohol resin.

The thickness of the adhesive layer formed of the dry curable adhesive is usually 0.001 μm to 5. Mu.m, preferably 0.01 μm to 2. Mu.m, and more preferably 0.01 μm to 0.5. Mu.m. If the adhesive layer formed of the dry curable adhesive is too thick, for example, an appearance defect is likely to occur in an elliptical polarizing plate formed of a polarizing plate and the optical film of the present invention.

[ Active energy ray-curable adhesive ]

The active energy ray-curable adhesive may contain a solvent. The active energy ray-curable adhesive means an adhesive cured by irradiation with active energy rays.

Examples of the active energy ray-curable adhesive include cationically polymerizable adhesives containing an epoxy compound and a cationic polymerization initiator; a radical polymerizable adhesive containing an acrylic curing component and a radical polymerization initiator; an adhesive containing both a cationically polymerizable curing component such as an epoxy compound and a radically polymerizable curing component such as an acrylic compound, and further containing a cationic polymerization initiator and a radical polymerization initiator; and adhesives which do not contain these polymerization initiators and cure by irradiation with electron beams.

Among them, a radical-polymerizable active energy ray-curable adhesive containing an acrylic curing component and a radical polymerization initiator, and a cation-polymerizable active energy ray-curable adhesive containing an epoxy compound and a cation polymerization initiator are preferable. Examples of the acrylic acid-based curing component include (meth) acrylic acid esters such as methyl (meth) acrylate and hydroxyethyl (meth) acrylate, and (meth) acrylic acid. The active energy ray-curable adhesive containing an epoxy compound may contain a compound other than the epoxy compound. Examples of the compound other than the epoxy compound include oxetane compounds and acrylic compounds.

The radical polymerization initiator may be the photopolymerization initiator described above. Examples of commercial products of the cationic polymerization initiator include "KAYARAD" (registered trademark) series (manufactured by japan chemical Co., ltd.), "CYRACURE UVI" series (manufactured by the dow chemical company), "CPI" series (manufactured by San-Apro co.), "TAZ", "BBI" and "DTS" (manufactured by midri Kagaku co., ltd., above), "ADEKA OPTOMER" series (manufactured by ADEKA corporation), "RHODORSIL" (manufactured by registered trademark) (manufactured by Rhodia corporation). The content of the radical polymerization initiator and the cationic polymerization initiator is usually 0.5 to 20 parts by mass, preferably 1 to 15 parts by mass, relative to 100 parts by mass of the active energy ray-curable adhesive.

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

In the present specification, the active energy ray is defined as: the compound capable of generating active species is decomposed to generate energy rays of the active species. Examples of such active energy rays include visible light, ultraviolet light, infrared light, X-rays, α -rays, β -rays, γ -rays, and electron beams, and ultraviolet light and electron beams are preferable. The irradiation conditions of ultraviolet rays are preferably the same as those of the polymerization of the polymerizable liquid crystal compound described above.

[ Display device ]

In the present invention, as one embodiment, a display device including the optical film of the present invention can be provided. The display device may include the elliptical 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. Examples of the display device include 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 (a field emission display device (FED or the like), a surface field emission display device (SED)), electronic paper (a display device using electronic ink or an electrophoretic element), a plasma display device, a projection display device (a grating light valve (GRATING LIGHT VALVE) (GLV) display device, a display device having a Digital Micromirror Device (DMD), and the like), and a piezoelectric ceramic display.

The liquid crystal display device includes any of a transmissive liquid crystal display device, a semi-transmissive liquid crystal display device, a reflective liquid crystal display device, a direct-view liquid crystal display device, a projection liquid crystal display device, and the like. These display devices may be display devices that display two-dimensional images, or may be stereoscopic display devices that display three-dimensional images. In particular, as a display device having the optical film and the polarizing plate of the present invention, an organic EL display device and a touch panel display device are preferable.

Examples (example)

The present invention will be described more specifically with reference to examples. In the examples, "%" and "parts" are represented by mass% and parts by mass unless otherwise specified. The polymer film, the apparatus and the measurement method used in the examples below are as follows.

As the cycloolefin polymer (COP) film, ZF-14 manufactured by Japanese ZEON Co., ltd.

AGF-B10 manufactured by Chun electric Co., ltd. Was used as the corona treatment device.

The corona treatment was performed 1 time under conditions of an output of 0.3kW and a treatment speed of 3 m/min using the corona treatment apparatus.

As polarized UV light irradiation apparatus, SPOTCURE SP-9 with polarizer unit manufactured by USHIO INC was used.

As a high-pressure mercury lamp, unicure VB-15201BY-A manufactured BY USHIO INC was used.

The in-plane phase difference Re (λ) was measured using KOBRA-WPR manufactured by KORKAKO SECURE CORPORATION.

The retardation value Rth (lambda) in the thickness direction and the film thickness were measured by using an Ellipsometer (Ellipsometer) M-220 manufactured by Japanese spectroscopic Co.

[ Preparation of alignment film composition for Forming first phase-difference layer ]

5 Parts (weight average molecular weight: 30000) of a photo-alignment material having the following structure and 95 parts of cyclopentanone (solvent) were mixed as components, and the resultant mixture was stirred at 80℃for 1 hour, thereby obtaining an alignment film composition for forming a first retardation layer.

[ Preparation of an alignment film composition for Forming a second phase-Difference layer ]

A silane coupling agent KBE-9103 produced by Xinyue chemical industries Co., ltd was dissolved in a solution of 9:1 (weight ratio) of ethanol and water to give an alignment film composition for forming a second phase difference layer having a solid content of 1%.

[ Preparation of first and second phase-difference layer-Forming compositions (compositions I to IV) ]

To a 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 Co., ltd.) and 6 parts of a polymerization initiator (2-dimethylamino-2-benzyl-1- (4-morpholinophenyl) butan-1-one (Irgacure 369 (Irg 369); manufactured by BASF Japan Co., ltd.) were added.

Further, N-methyl-2-pyrrolidone (NMP) was added as a solvent so that the solid content concentration became 13%, and stirring was performed at 80 ℃ for 1 hour, thereby obtaining first and second phase difference layer-forming compositions. The mixture ratio of the polymerizable liquid crystal compound a and the polymerizable liquid crystal compound B was added as shown in table 1 according to the target wavelength dispersion value α, and the names of the respective compositions were defined as shown in table 1.

TABLE 1

The ratio of the polymerizable liquid crystal compounds a and B in the respective examples is a ratio relative to the total amount of the polymerizable liquid crystal compounds.

The polymerizable liquid crystal compound A is produced by the method described in JP-A2010-31223. The polymerizable liquid crystal compound B is produced according to the method described in japanese patent application laid-open No. 2009-173893. The respective molecular structures are shown below.

Polymerizable liquid Crystal Compound A

Polymerizable liquid Crystal Compound B

[ Preparation of liquid Crystal composition for Forming first and second phase-Difference layers (composition V) ]

The liquid crystal compound LC242 described below: paliocolorLC242 (registered trademark of BASF corporation) to which 0.1 part of a leveling agent F-556 and 3 parts of a polymerization initiator Irg369 were added, cyclopentanone was added so that the solid content concentration became 13%, to obtain a liquid crystal composition for forming first and second phase difference layers. The name of the obtained liquid crystal composition was designated as "composition V".

Liquid crystal compound LC242: paliocolorLC242 (BASF corporation registered trademark)

Example 1

[ Production of first retardation layer ]

The composition for forming the first retardation layer was coated on a COP film (ZF-14-50) manufactured by ZEON Co., ltd. In Japan using a bar coater, dried at 80℃for 1 minute, and exposed to polarized UV light at an axial angle of 45℃under the condition that the cumulative light amount at the wavelength of 313nm was 100mJ/cm ² using a polarized UV light irradiation apparatus (SPOTCURE SP-9; USHIO INC). The film thickness of the obtained alignment film for forming the first retardation layer was measured by ellipsometry, and found to be 100nm.

Next, the composition I was applied to an alignment film for forming a first retardation layer using a bar coater, dried at 120 ℃ for 1 minute, and then irradiated with ultraviolet light (cumulative light amount at 365nm wavelength: 500mJ/cm ² under nitrogen atmosphere) from the side on which the composition for forming a retardation layer was applied using a high-pressure mercury lamp (Unicure VB-15201BY-a, manufactured BY usio inc.). The film thickness of the obtained first retardation layer was measured by ellipsometry and found to be 2.3. Mu.m.

[ Production of second phase Difference layer ]

The composition for forming an alignment film for forming a second phase difference layer was applied onto a COP film (ZF-14-50) manufactured by ZEON Co., ltd. In Japan using a bar coater, and dried at 120℃for 1 minute to obtain an alignment film for forming a second phase difference layer. The film thickness of the obtained second phase difference layer-forming alignment film was measured by ellipsometry and found to be 200nm.

Next, the composition I was applied to an alignment film for forming a second phase difference layer using a bar coater, dried at 120 ℃ for 1 minute, and then irradiated with ultraviolet rays (cumulative light amount at 365nm wavelength: 500mJ/cm ² under nitrogen atmosphere) from the side on which the phase difference layer composition was applied using a high-pressure mercury lamp (Unicure VB-15201BY-a, manufactured BY usio inc.). The film thickness of the obtained second phase difference layer was measured by ellipsometry and found to be 1.2. Mu.m.

Re measurement of first phase Difference layer and second phase Difference layer

In-plane phase difference values (Re 1 (λ) and Re2 (λ)) of the first phase difference layer and the second phase difference layer manufactured by the above method were measured at wavelengths λ of 450nm, 550nm, and 650nm by a measuring instrument (KOBRA-WR, manufactured by prince measuring instruments) after confirming that no phase difference exists in the cycloolefin polymer film as a base material. The results obtained are shown in Table 2.

[ Rth measurement of first phase-difference layer and second phase-difference layer ]

The retardation values (Rth 1 (λ) and Rth2 (λ)) in the thickness direction of the first retardation layer and the second retardation layer manufactured by the above method were measured by changing the incident angle of light incident on the sample by an ellipsometer after confirming that no retardation was present in the cycloolefin polymer film as a base material. In addition, the average refractive index at wavelengths λ of 450nm and 550nm was measured using a refractive index meter (ATAGO co., ltd. Manufactured by the company "multi-wavelength abbe refractometer DR-M4"). Table 2 shows Rth1 (λ) and Rth2 (λ) at wavelengths λ of 450nm and 550nm calculated from the measurement results of ellipsometry, and the obtained film thickness and average refractive index.

[ Calculation of Nz (lambda) ]

Nz (λ) of the optical film in which the first phase difference layer and the second phase difference layer are laminated is calculated according to formula (C). The calculated results are shown in table 2.

The refractive indices nx1 (λ), ny1 (λ), and nz1 (λ) of the obtained first retardation layer satisfy nx1 (λ) > ny1 (λ) ≡nz1 (λ) over the entire range of wavelengths λ=400 to 700 nm. The refractive indices nx2 (λ), ny2 (λ), and nz2 (λ) of the second phase difference layer satisfy nz2 (λ) > nx2 (λ) ≡ny2 (λ) over the entire range of wavelengths λ=400 to 700 nm.

[ Production of polarizing plate ]

A polyvinyl alcohol film having an average polymerization degree of about 2,400 and a saponification degree of 99.9 mol% or more and a thickness of 75 μm was immersed in pure water at 30℃and then immersed in an aqueous solution having a weight ratio of iodine/potassium iodide/water of 0.02/2/100 at 30℃to carry out iodine dyeing (iodine dyeing step). The polyvinyl alcohol film after the iodine dyeing step was immersed in an aqueous solution having a weight ratio of potassium iodide/boric acid/water of 12/5/100 at 56.5 ℃ to carry out boric acid treatment (boric acid treatment step). The polyvinyl alcohol film after the boric acid treatment step was washed with pure water at 8℃and then dried at 65℃to obtain a polarizer in which iodine was adsorbed and oriented in polyvinyl alcohol (thickness after stretching: 27 μm). At this time, stretching is performed in the iodine dyeing step and the boric acid treatment step. The total stretch ratio in the stretching was 5.3 times. The obtained polarizer was bonded to a saponified triacetylcellulose film (KC 4UYTAC,40 μm, manufactured by Konica Minolta) via a water-based adhesive using a nip roll. The resulting laminate was dried at 60℃for 2 minutes while maintaining the tension of the laminate at 430N/m, to obtain a polarizing plate having a triacetyl cellulose film as a protective film on one side. The water-based adhesive was prepared by adding 3 parts of carboxyl group-modified polyvinyl alcohol (Kuraray co., ltd. Kuraray POVAL KL 318) and 1.5 parts of water-soluble polyamide epoxy resin (Sumika Chemtex co., ltd. SUMIREZRESIN, SUMIREZRESIN g 650, aqueous solution with a solid content of 30%) to 100 parts of water.

The optical characteristics of the obtained polarizing plate were measured. The polarizing plate obtained above was measured by a spectrophotometer (V7100, manufactured by japan spectroscopy) with the polarizing plate surface thereof as an incident surface. The obtained visibility-corrected monomer had a transmittance of 42.1%, a visibility-corrected polarization degree of 99.996%, a monomer color tone a of-1.1, and a monomer color tone b of 3.7.

[ Manufacture of elliptical polarizing plate ]

First, the surface of the first retardation layer was subjected to corona treatment, and then, a polarizing plate manufactured by the above method was bonded to the surface via an adhesive (pressure-sensitive adhesive made of Lintec Corporation μm), and then, the base material was peeled off to form a laminate of the polarizing plate and the first retardation layer.

Then, the surface of the second retardation layer was subjected to corona treatment, and then the first retardation layer and the second retardation layer in the laminate of the polarizing plate and the first retardation layer were bonded via an adhesive (pressure-sensitive adhesive made of Lintec Corporation μm). Then, the base material was peeled off to obtain an elliptical polarizing plate.

[ Confirmation of front tone and oblique tone Change ]

The obtained elliptical polarizing plate was attached to a mirror via an adhesive, and then visually observed from the front at a distance of 50cm therefrom to confirm the color tone. The oblique color tone was confirmed by visual observation from the direction of 60 ° in elevation and 0 to 360 ° in azimuth at a distance of 50cm therefrom. The results of the confirmation are shown in table 2.

The front tone and the oblique tone are as follows.

And (3) the following materials: clear black, o: black, delta: black, red or blue, x: red or blue

Examples 2 to 30 and comparative examples 1 to 12

An optical film and an elliptical polarizing plate were produced in the same manner as in example 1, except that the composition I was changed to the composition II, the composition III, the composition IV or the composition V, respectively, as described in table 2. The measurement results are shown in Table 2.

The refractive indices nx1 (λ), ny1 (λ), and nz1 (λ) of the first retardation layers obtained in examples 2 to 30 satisfy nx1 (λ) > ny1 (λ) ≡nz1 (λ) over the entire range of wavelengths λ=400 to 700 nm. The refractive indices nx2 (λ), ny2 (λ), and nz2 (λ) of the second phase difference layer satisfy nz2 (λ) > nx2 (λ) ≡ny2 (λ) over the entire range of wavelengths λ=400 to 700 nm.

Example 31

An optical film and an elliptical polarizing plate were produced in the same manner as in example 1, except that the composition I was changed as described in table 2, and the order of lamination of the first retardation layer and the second retardation layer in the method for producing an elliptical polarizing plate was changed to the order of lamination of the polarizing plate and the second retardation layer, and then the laminate of the polarizing plate and the second retardation layer and the first retardation layer were laminated. The measurement results are shown in Table 2.

The refractive indices nx1 (λ), ny1 (λ) and nz1 (λ) of the first retardation layer obtained in example 31 satisfy nx1 (λ) > ny1 (λ) ≡nz1 (λ) over the entire range of wavelengths λ=400 to 700 nm. The refractive indices nx2 (λ), ny2 (λ), and nz2 (λ) of the second phase difference layer satisfy nz2 (λ) > nx2 (λ) ≡ny2 (λ) over the entire range of wavelengths λ=400 to 700 nm.

TABLE 2

The elliptical polarizing plate having the first retardation layer and the second retardation layer described in the examples had black front tone and oblique tone, and had excellent antireflection characteristics.

Claims (12)

1. An optical film having a first phase difference layer and a second phase difference layer and satisfying the relationship of the following formulas (1) and (2),

0.4≤Nz（450）≤0.6 （1）

0.4≤Nz（550）≤0.6 （2）

Wherein Nz (450) represents the Nz coefficient of the optical film for light having a wavelength of λ=450 nm, nz (550) represents the Nz coefficient of the optical film for light having a wavelength of λ=550 nm,

The Nz coefficient Nz (λ) of the optical film for light of wavelength λ (nm) is represented by the following formula:

Nz（λ）=（nx（λ）-nz（λ））/（nx（λ）-ny（λ））

nx (λ) represents: in an ellipsoid of refractive index formed by an optical film, a principal refractive index for light of wavelength lambda (nm) in a direction parallel to a film plane,

Ny (λ) represents: in an ellipsoid of refractive index formed by an optical film, the refractive index of light of wavelength lambda (nm) in a direction parallel to the film plane and orthogonal to the direction of nx (lambda),

Nz (λ) represents: in an ellipsoid of refractive index formed by an optical film, the refractive index of light of wavelength lambda (nm) in a direction perpendicular to the film plane,

As for the first phase difference layer,

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

Wherein nx1 (λ) represents: in the index ellipsoid formed by the first phase difference layer, the principal refractive index of light of wavelength lambda (nm) in a direction parallel to the film plane,

Ny1 (λ) represents: in the refractive index ellipsoid formed by the first phase difference layer, the refractive index of light of wavelength lambda (nm) in a direction parallel to the film plane and orthogonal to the direction of nx1 (lambda),

Nz1 (λ) represents: in the refractive index ellipsoid formed by the first phase difference layer, the refractive index of light of wavelength λ (nm) in the direction perpendicular to the film plane;

the first phase difference layer satisfies 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) represents the in-plane phase difference value of the first phase difference layer for light with wavelength lambda=450 nm, re1 (550) represents the in-plane phase difference value of the first phase difference layer for light with wavelength lambda=550 nm, re1 (650) represents the in-plane phase difference value of the first phase difference layer for light with wavelength lambda=650 nm,

The in-plane retardation Re1 (λ) of the first retardation layer with respect to light having a wavelength of λnm is represented by the following formula:

Re1（λ）=（nx1（λ）-ny1（λ））×d1

wherein d1 represents the thickness of the first retardation layer,

For the second phase difference layer,

In the refractive index ellipsoid formed by the second phase difference layer, there is a relationship of nz2 (λ) > nx2 (λ) ≡ny2 (λ) in a range of wavelength λ=400 to 700nm,

Wherein nz2 (λ) represents: in the refractive index ellipsoid formed by the second phase difference layer, the refractive index of light of wavelength lambda (nm) in the direction perpendicular to the film plane,

Nx2 (λ) represents: in the refractive index ellipsoid formed by the second phase difference layer, the maximum refractive index for light of wavelength lambda (nm) in the direction parallel to the film plane,

Ny2 (λ) represents: in the refractive index ellipsoid formed by the second phase difference layer, the refractive index of light of wavelength lambda (nm) in a direction parallel to the film plane and orthogonal to the direction of nx2 (lambda),

Where nx2 (λ) =ny2 (λ), nx2 (λ) represents a refractive index in an arbitrary direction parallel to the film plane;

and the second phase difference layer satisfies 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) represents a phase difference value of light having a wavelength of λ=450 nm in a thickness direction, rth2 (550) represents a phase difference value of light having a wavelength of λ=550 nm in a thickness direction of the second phase difference layer, rth2 (650) represents a phase difference value of light having a wavelength of 650nm in a thickness direction of the second phase difference layer,

The phase difference value Rth2 (λ) for light of wavelength λ (nm) in the thickness direction of the second phase difference layer is represented by the following formula:

Rth2（λ）=[（nx2（λ）+ny2（λ））/2-nz2（λ）]×d2

Wherein, in the refractive index ellipsoid formed by the second phase difference layer, nz2 (λ) represents the principal refractive index in the direction perpendicular to the film plane at the wavelength λ (nm) ((nx 2 (λ) +ny2 (λ))/2) represents the average refractive index of the film plane at the wavelength λ (nm), d2 represents the thickness of the second phase difference layer,

The first phase difference layer is a liquid crystal cured film obtained by curing a polymerizable liquid crystal compound in a state of being oriented in a direction horizontal to the substrate surface,

The second phase difference layer is a liquid crystal cured film obtained by curing a polymerizable liquid crystal compound in a state of being oriented in a direction perpendicular to the substrate surface.

2. The optical film according to claim 1, wherein the second phase difference layer is a film formed of a coating layer formed by polymerizing a polymerizable liquid crystal in an aligned state.

3. The optical film according to claim 1 or 2, wherein the first retardation layer is a film formed of a coating layer formed by polymerizing a polymerizable liquid crystal in an aligned state.

4. The optical film according to claim 1 or 2, wherein the second phase difference layer is 5 μm or less.

5. The optical film according to claim 1 or 2, wherein the first retardation layer is 5 μm or less.

6. The optical film according to claim 1 or 2, wherein the first phase difference layer and the second phase difference layer are coating layers formed by polymerizing mainly the same polymerizable liquid crystal compound.

7. An elliptical polarizing plate with an optical compensation function, having the optical film and the polarizing plate according to any one of claims 1 to 6.

8. The elliptical polarizing plate with an optical compensation function of claim 7, wherein the absorption axis of the polarizing plate and the slow axis of the first phase difference 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 phase difference layer are orthogonal to the slow axis of the second phase difference layer in a direction perpendicular to the film plane.

9. The elliptical polarizing plate with an optical compensation function according to claim 7 or 8, which is an optical laminate obtained by sequentially forming a polarizing plate, an adhesive layer, a first retardation layer, an adhesive layer, and a second retardation layer.

10. The elliptical polarizing plate with an optical compensation function according to claim 7 or 8, which is an optical laminate obtained by sequentially forming a polarizing plate, an adhesive layer, a second retardation layer, an adhesive layer, and a first retardation layer.

11. An organic EL display device having the elliptical polarizing plate with an optical compensation function as defined in any one of claims 8 to 10.

12. The method for producing an elliptical polarizing plate with an optical compensation function according to any one of claims 7 to 10, comprising the steps of:

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

(step 1-B) a step of forming a second phase difference layer by applying a polymerizable liquid crystal compound to a substrate on which a vertical alignment film is formed and then polymerizing the substrate in a vertically aligned state; and

(Step 2) transferring and laminating the liquid crystal polymer of the first retardation layer and the liquid crystal polymer of the second retardation layer from the base material to the polarizing plate via the adhesive.