JP2004078203A - Optical film and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical film which is excellent in optical characteristics and can easily be manufactured at a low cost. <P>SOLUTION: In this optical film where a transparent macromolecular film layer and a birefringent layer made of non-liquid crystal polymer are laminated, the birefringent layer satisfies the condition of the following equation (1), and in-plane phase difference of the transparent macromolecular film layer is set to ≤50 nm. The equation (1) is nx ≥ ny > nz, wherein nx, ny, and nz are the refractive indexes of an X axes direction, a Y axis direction and a Z axis direction, respectively. The X axis direction is an axial direction showing a maximum refractive index in the in-plane direction of the birefringent layer, the Y axis direction is an axial direction perpendicular to the X axis direction in the plane, and the Z axis direction shows a thickness direction perpendicular to the X axis direction and the Y axis direction. <P>COPYRIGHT: (C)2004,JPO

Description

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

Various optical films are used in liquid crystal display devices to improve display performance. For example, an optical film (retardation film) that satisfies the following condition (1) is disposed between a liquid crystal cell and a polarizing plate, and is used to perform viewing angle compensation of a liquid crystal display device. Such an optical film is manufactured by stretching a polymer film (see Patent Documents 1, 2, and 3).

nx ≧ ny> nz (1)

In the above formula (1), nx, ny and nz indicate the refractive indexes of the optical film in the X-axis direction, the Y-axis direction and the Z-axis direction, respectively.
The X-axis direction is an axial direction indicating the maximum refractive index in the in-plane direction of the optical film, the Y-axis direction is an axial direction perpendicular to the X-axis direction in the plane, The Z-axis direction indicates a thickness direction perpendicular to the X-axis direction and the Y-axis direction.

However, in the production method using the stretching method, it is necessary to set conditions such as the stretching ratio and the stretching direction in detail, and it is necessary to precisely control the stretching process, which complicates the process. In the stretching method, it is necessary to solve the bowing phenomenon. Further, in the stretching method, it is necessary to use a polymer film having a certain thickness, and thus the obtained optical film has a thickness, and as a result, there is a problem that the liquid crystal display device also becomes thick.

On the other hand, there is a method for producing an optical film without using a stretching treatment. For example, a solution of a polymer such as polyamide, polyimide, polyester, polyetherketone, polyamideimide and polyesterimide is applied to a substrate having a smooth surface, and the solvent of the solution is evaporated to form an optical film. (See Patent Documents 4, 5, 6, 7, and 8). As the substrate, an inorganic substrate such as a SUS belt, a copper thin plate, a glass plate, and a Si wafer is mainly used. However, when an inorganic substrate is used, it cannot be used for a liquid crystal display device itself, and therefore, it is necessary to transfer an optical film from the substrate to a polarizer or the like. Also, an optical film formed on a substrate is peeled off from the substrate and wound up. As described above, when an inorganic substrate is used, the production of an optical film becomes complicated, and there is also a problem that the cost of the inorganic substrate is high.

As described above, the conventional optical film has a problem in its manufacturing method, but the optical film itself is required to have further improved optical characteristics.
JP-A-3-33719 JP-A-3-24502 JP-A-4-194820 U.S. Pat. No. 5,344,916 U.S. Pat. No. 5,395,918 (Japanese Unexamined Patent Publication No. Hei 8-511812). US Patent No. 5,480,964 US Patent No. 5,580,950 U.S. Pat. No. 6,074,709

Therefore, an object of the present invention is to provide an optical film which can be manufactured easily and at low cost and has excellent optical characteristics, and a method for manufacturing the same.

In order to solve the above problems, the optical film of the present invention is an optical film in which a transparent polymer film layer and a birefringent layer formed of a non-liquid crystalline polymer are laminated, wherein the birefringent layer is The condition of the formula (1) is satisfied, and the in-plane retardation of the transparent polymer film layer is 50 nm or less.

nx ≧ ny> nz (1)
In the above formula (1), nx, ny and nz indicate the refractive indexes of the birefringent layer in the X-axis direction, the Y-axis direction and the Z-axis direction, respectively.
The X-axis direction is an axial direction indicating a maximum refractive index in the in-plane direction of the birefringent layer, the Y-axis direction is an axial direction perpendicular to the X-axis direction in the plane, The Z-axis direction indicates a thickness direction perpendicular to the X-axis direction and the Y-axis direction.

Next, the method for producing an optical film of the present invention is a method for producing an optical film in which a transparent polymer film layer and a birefringent layer are laminated, wherein a transparent polymer film having an in-plane retardation of 50 nm or less is prepared. Then, a non-liquid crystalline polymer solution is applied thereon, and a solvent in the solution is removed by evaporation to form a birefringent layer. The birefringent layer is formed so as to satisfy the condition of the formula (1). Manufacturing method.

As described above, the optical film of the present invention uses the transparent polymer film layer as the base material and the birefringent layer is laminated thereon, so that it can be used as it is in a laminated state, and can be used for peeling work from the base material or winding. No take-up work is required, and the transparent polymer film layer is inexpensive. For this reason, the optical film of the present invention can be manufactured simply and at low cost as compared with the related art. In the optical film of the present invention, the transparent polymer film layer has an in-plane retardation of 50 nm or less. Therefore, the retardation of the entire optical film can be set in an appropriate range, and the optical film has excellent optical characteristics such as contrast and viewing angle characteristics.

Next, the present invention will be described in detail.

In the optical film of the present invention, the birefringent layer needs to satisfy the above condition 1. FIG. 4 shows an example of the refractive indexes nx, ny and nz in the birefringent layer. As shown in the drawing, nx, ny, and nz indicate the refractive indexes of the birefringent layer in the X-axis direction, the Y-axis direction, and the Z-axis direction, respectively. The X-axis direction is an axial direction indicating a maximum refractive index in the in-plane direction of the birefringent layer, the Y-axis direction is an axial direction perpendicular to the X-axis direction in the plane, The Z-axis direction indicates a thickness direction perpendicular to the X-axis direction and the Y-axis direction.

If the optical film has optical characteristics of nx = ny> nz, it has optically uniaxial characteristics, and such an optical film is generally called a C plate. In the case where the optical characteristics satisfy nx>ny> nz, the characteristics are optically biaxial. In the case of an optically uniaxial characteristic, nx and ny basically match, but an actual measurement value has an error. In the case where the thickness (d) of the birefringent layer is, for example, 0.1 μm to 50 μm, if Δnd = (nx−ny) · d <5 nm, it can be said that the optically uniaxial characteristic, and Is optically biaxial. The birefringent layer of the present invention may be optically uniaxial or biaxial, and thus does not need to be strictly distinguished.

In the optical film and the method of manufacturing the same according to the present invention, the birefringence Δn (a) of the birefringent layer and the birefringence Δn (b) of the transparent polymer film layer are represented by the following formulas (2) to (7). It is preferable that one of the conditions is satisfied. By satisfying this condition, optical characteristics such as contrast and viewing angle characteristics are further improved. It is to be noted that, in the following equation, the equation becomes more preferable from equation (2) to equation (7).

Δn (a)> Δn (b) × 10 (2)
Δn (a)> Δn (b) × 15 (3)
Δn (a)> Δn (b) × 20 (4)
Δn (a)> Δn (b) × 30 (5)
Δn (a)> Δn (b) × 40 (6)
Δn (a)> Δn (b) × 50 (7)
In the optical film of the present invention and the method for producing the same, the birefringence (Δn) of the entire optical film is preferably in the range of 0.0005 to 0.5. When Δn is 0.0005 or more, it is possible to make the optical film thin, and when Δn is 0.5 or less, there is an advantage that the phase difference can be easily controlled. A more preferable range of Δn is a range of 0.001 to 0.2, and a still more preferable range is a range of 0.002 to 0.15.

In the optical film and the method for producing the same according to the present invention, the non-liquid crystalline polymer forming the birefringent layer is not particularly limited, and examples thereof include polyamide, polyimide, polyester, polyetherketone, polyamideimide, polyesterimide, and mixtures thereof. Is raised.

In the optical film of the present invention and the method for producing the same, the resin forming the transparent polymer film layer is not particularly limited, for example, acetate resin, polyester resin, polyether sulfone resin, polysulfone resin, polycarbonate resin, polyamide resin, Polyimide resin, polyolefin resin, acrylic resin, polynorbornene resin, cellulose resin, polyarylate resin, polystyrene resin, polyvinyl alcohol resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyacryl resin, their mixed resin, liquid crystal polymer, and Examples include a mixture of a thermoplastic resin having a substituted imide group or an unsubstituted imide group in a side chain and a thermoplastic resin having a substituted phenyl group or an unsubstituted phenyl group and a nitrile group in a side chain. As the acetate resin, for example, there is triacetyl acetate. Examples of a mixture of a thermoplastic resin having a substituted imide group or an unsubstituted imide group in a side chain and a thermoplastic resin having a substituted phenyl group or an unsubstituted phenyl group and a nitrile group in a side chain include, for example, isobutene and N There is a mixed resin of an alternating copolymer of methylene maleimide and an acrylonitrile / styrene copolymer.

In the optical film and the method for producing the same according to the present invention, the transparent polymer film layer is not particularly limited, and may be produced by molding a resin for forming the film into a film shape and performing a stretching treatment. . In the method for producing an optical film of the present invention, after laminating the transparent polymer film layer and the birefringent layer, the laminate may be stretched or shrunk.

に お い て In the optical film and the method for producing the same according to the present invention, the transparent polymer film layer may be used as a transparent protective film for a polarizing plate.

偏光 The polarizing plate of the present invention is a polarizing plate including an optical film and a polarizer, wherein the optical film is the optical film of the present invention. It is preferable that the transparent polymer film layer of the optical film also functions as a transparent protective film of the polarizing plate. Further, it is preferable that the optical film functions as an optical compensation layer.

The liquid crystal panel of the present invention is a liquid crystal panel including a liquid crystal cell and an optical member, wherein the optical member is disposed on at least one surface of the liquid crystal cell, and the optical member is the optical film or the optical film of the present invention. 3 is a polarizing plate of the present invention. The type of the liquid crystal cell of the present invention is not particularly limited, and for example, a STN (Super Twisted Nematic) cell, a TN (Twisted Nematic) cell, an IPS (In-Plane Switching) cell, a VA (Vertical Aligned) cell, an OCB ( There are an optically aligned birefringence (HAN) cell, a HAN (hybrid aligned nematic) cell, and an ASM (Axially Symmetric Alighned Microcell) cell. Among them, the optical film of the present invention is preferably applied to VA cells and OCB cells.

The liquid crystal display of the present invention is a liquid crystal display including the liquid crystal panel of the present invention.

The self-luminous display device of the present invention is a self-luminous display device including at least one of the optical film of the present invention and the polarizing plate of the present invention. Examples of the self-luminous display device include an organic EL display.

Next, an example of the method for producing the optical film of the present invention will be described. The optical film of the present invention is prepared, for example, by preparing a transparent polymer film having an in-plane retardation of 50 nm or less, coating a non-liquid crystalline polymer solution thereon, and removing the solvent in the solution by evaporation. A birefringent layer can be manufactured by forming a refracting layer and satisfying the condition of the formula (1).

As the non-liquid crystalline polymer used for forming the birefringent layer, as described above, for example, heat resistance, chemical resistance, excellent in transparency, rich in rigidity, polyamide, polyimide, polyester, polyether Preferred are polymers such as ketones, polyaryletherketones, polyamideimides, polyesterimides and the like. One of these polymers may be used alone, or may be used as a mixture of two or more having different functional groups, for example, a mixture of a polyaryletherketone and a polyamide. . Among such polymers, polyimide is particularly preferable because of high transparency, high orientation and high stretchability.

Although the molecular weight of the polymer is not particularly limited, for example, the weight average molecular weight (Mw) is preferably in the range of 1,000 to 1,000,000, more preferably in the range of 2,000 to 500,000. is there.

ポ リ イ ミ ド As the polyimide, for example, polyimide having high in-plane orientation and soluble in an organic solvent is preferable. Specifically, for example, it includes a condensation polymerization product of 9,9-bis (aminoaryl) fluorene and an aromatic tetracarboxylic dianhydride, disclosed in JP-T-2000-511296, and has the following formula ( A polymer containing one or more repeating units shown in 1) can be used.

　前記式（１）中、Ｒ³〜Ｒ⁶は、水素、ハロゲン、フェニル基、１〜４個のハロゲン原子またはＣ１〜１０アルキル基で置換されたフェニル基、およびＣ１〜１０アルキル基からなる群からそれぞれ独立に選択される少なくとも一種類の置換基である。好ましくは、Ｒ³〜Ｒ⁶は、ハロゲン、フェニル基、１〜４個のハロゲン原子またはＣ１〜１０アルキル基で置換されたフェニル基、およびＣ１〜１０アルキル基からなる群からそれぞれ独立に選択される少なくとも一種類の置換基である。

In the formula (1), R ^{3 to} R ^{6 each} represent a group consisting of hydrogen, halogen, a phenyl group, a phenyl group substituted with 1 to 4 halogen atoms or C1 to 10 alkyl groups, and a C1 to 10 alkyl group. And at least one substituent independently selected from Preferably, R ^{3 to} R ⁶ are each independently selected from the group consisting of a halogen, a phenyl group, a phenyl group substituted with 1 to 4 halogen atoms or C 1 to 10 alkyl groups, and a C 1 to 10 alkyl group. At least one type of substituent.

In the formula (1), Z is, for example, a C6-20 tetravalent aromatic group, preferably a pyromellitic group, a polycyclic aromatic group, a derivative of a polycyclic aromatic group, or It is a group represented by the formula (2).

　前記式（２）中、Ｚ'は、例えば、共有結合、Ｃ(Ｒ⁷)₂基、ＣＯ基、Ｏ原子、Ｓ原子、ＳＯ₂基、Ｓｉ(Ｃ₂Ｈ₅)₂基、または、ＮＲ⁸基であり、複数の場合、それぞれ同一であるかまたは異なる。また、ｗは、１から１０までの整数を表す。Ｒ⁷は、それぞれ独立に、水素またはＣ（Ｒ⁹）₃である。Ｒ⁸は、水素、Ｃ１〜Ｃ２０のアルキル基、またはＣ６〜２０アリール基であり、複数の場合、それぞれ同一であるかまたは異なる。Ｒ⁹は、それぞれ独立に、水素、フッ素、または塩素である。

In the formula (2), Z ′ is, for example, a covalent bond, a C (R ⁷ ) ₂ group, a CO group, an O atom, a S atom, a SO ₂ group, a Si (C ₂ H ₅ ) ₂ group, or an NR. ^{There are eight} groups, and in the case of a plurality, they are the same or different. W represents an integer of 1 to 10. R ⁷ is each independently hydrogen or C (R ⁹ ) ₃ . R ⁸ is hydrogen, a C1 to C20 alkyl group, or a C6 to 20 aryl group, and in the case of a plurality, R ⁸ is the same or different. R ⁹ is each independently hydrogen, fluorine, or chlorine.

{Examples of the polycyclic aromatic group include a tetravalent group derived from naphthalene, fluorene, benzofluorene or anthracene. The substituted derivative of the polycyclic aromatic group is, for example, substituted with at least one group selected from the group consisting of a C1-10 alkyl group, a fluorinated derivative thereof, and a halogen such as F or Cl. And the above-mentioned polycyclic aromatic groups.

In addition, for example, a homopolymer represented by the following general formula (3) or (4) and a repeating unit represented by the following general formula (5) described in JP-T-8-511812 are disclosed. And the like. The polyimide of the following formula (5) is a preferred form of the homopolymer of the following formula (3).

　前記一般式（３）〜（５）中、ＧおよびＧ'は、例えば、共有結合、ＣＨ₂基、Ｃ(ＣＨ₃)₂基、Ｃ(ＣＦ₃)₂基、Ｃ(ＣＸ₃)₂基（ここで、Ｘは、ハロゲンである。）、ＣＯ基、Ｏ原子、Ｓ原子、ＳＯ₂基、Ｓｉ(ＣＨ₂ＣＨ₃)₂基、および、Ｎ(ＣＨ₃)基からなる群から、それぞれ独立して選択される基を表し、それぞれ同一でも異なってもよい。

In the general formulas (3) to (5), G and G ′ are, for example, a covalent bond, a CH ₂ group, a C (CH ₃ ) ₂ group, a C (CF ₃ ) ₂ group, a C (CX ₃ ) ₂ group (Where X is a halogen), CO, O, S, SO ₂ , Si (CH ₂ CH ₃ ) ₂ , and N (CH ₃ ) groups. Represents an independently selected group, which may be the same or different.

中 In the above formulas (3) and (5), L is a substituent, and d and e represent the number of substitutions. L is, for example, a halogen, a C1-3 alkyl group, a C1-3 halogenated alkyl group, a phenyl group, or a substituted phenyl group, and in the case of a plurality, L is the same or different. Examples of the substituted phenyl group include a substituted phenyl group having at least one substituent selected from the group consisting of a halogen, a C1-3 alkyl group, and a C1-3 halogenated alkyl group. Examples of the halogen include fluorine, chlorine, bromine and iodine. d is an integer from 0 to 2, and e is an integer from 0 to 3.

中 In the formulas (3) to (5), Q represents a substituent, and f represents the number of substitutions. Q is, for example, selected from the group consisting of hydrogen, halogen, an alkyl group, a substituted alkyl group, a nitro group, a cyano group, a thioalkyl group, an alkoxy group, an aryl group, a substituted aryl group, an alkyl ester group, and a substituted alkyl ester group. And when Q is plural, each is the same or different. Examples of the halogen include fluorine, chlorine, bromine and iodine. Examples of the substituted alkyl group include a halogenated alkyl group. Examples of the substituted aryl group include a halogenated aryl group. f is an integer from 0 to 4, and g and h are integers from 0 to 3 and 1 to 3, respectively. Further, g and h are preferably larger than 1.

In the formula (4), R ¹⁰ and R ¹¹ are groups independently selected from the group consisting of hydrogen, halogen, phenyl group, substituted phenyl group, alkyl group, and substituted alkyl group. Among them, R ¹⁰ and R ¹¹ are preferably each independently a halogenated alkyl group.

中 In the above formula (5), M1 and M2 are the same or different and are, for example, halogen, C1-3 alkyl group, C1-3 halogenated alkyl group, phenyl group, or substituted phenyl group. Examples of the halogen include fluorine, chlorine, bromine and iodine. Examples of the substituted phenyl group include a substituted phenyl group having at least one substituent selected from the group consisting of a halogen, a C1-3 alkyl group, and a C1-3 halogenated alkyl group.

具体 Specific examples of the polyimide represented by the formula (3) include, for example, those represented by the following formula (6).

　さらに、前記ポリイミドとしては、例えば、前述のような骨格（繰り返し単位）以外の酸二無水物やジアミンを、適宜共重合させたコポリマーがあげられる。

Further, examples of the polyimide include a copolymer obtained by appropriately copolymerizing an acid dianhydride or a diamine other than the above-described skeleton (repeating unit).

Examples of the acid dianhydride include aromatic tetracarboxylic dianhydride. As the aromatic tetracarboxylic dianhydride, for example, pyromellitic dianhydride, benzophenone tetracarboxylic dianhydride, naphthalene tetracarboxylic dianhydride, heterocyclic aromatic tetracarboxylic dianhydride, 2, 2'-substituted biphenyltetracarboxylic dianhydride and the like.

Examples of the pyromellitic dianhydride include pyromellitic dianhydride, 3,6-diphenyl pyromellitic dianhydride, 3,6-bis (trifluoromethyl) pyromellitic dianhydride, 3,6-dibromo Pyromellitic dianhydride, 3,6-dichloropyromellitic dianhydride and the like. Examples of the benzophenone tetracarboxylic dianhydride include 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 2,3,3 ′, 4′-benzophenone tetracarboxylic dianhydride, , 2 ', 3,3'-benzophenonetetracarboxylic dianhydride and the like. Examples of the naphthalenetetracarboxylic dianhydride include 2,3,6,7-naphthalene-tetracarboxylic dianhydride, 1,2,5,6-naphthalene-tetracarboxylic dianhydride and 2,6 -Dichloro-naphthalene-1,4,5,8-tetracarboxylic dianhydride and the like. Examples of the heterocyclic aromatic tetracarboxylic dianhydride include thiophene-2,3,4,5-tetracarboxylic dianhydride and pyrazine-2,3,5,6-tetracarboxylic dianhydride And pyridine-2,3,5,6-tetracarboxylic dianhydride. Examples of the 2,2′-substituted biphenyltetracarboxylic dianhydride include 2,2′-dibromo-4,4 ′, 5,5′-biphenyltetracarboxylic dianhydride and 2,2′-dichloro -4,4 ', 5,5'-biphenyltetracarboxylic dianhydride, 2,2'-bis (trifluoromethyl) -4,4', 5,5'-biphenyltetracarboxylic dianhydride and the like can give.

Other examples of the aromatic tetracarboxylic dianhydride include 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and bis (2,3-dicarboxyphenyl) methane dianhydride. , Bis (2,5,6-trifluoro-3,4-dicarboxyphenyl) methane dianhydride, 2,2-bis (3,4-dicarboxyphenyl) -1,1,1,1,3,3, 3-hexafluoropropane dianhydride, 4,4′-bis (3,4-dicarboxyphenyl) -2,2-diphenylpropane dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, 4,4'-oxydiphthalic dianhydride, bis (3,4-dicarboxyphenyl) sulfonic dianhydride, 3,3 ', 4,4'-diphenylsulfonetetracarboxylic dianhydride, 4,4' -[4,4'-isopropylidene-di (p-phenyleneoxy)] bis (phthalic anhydride), N, N- (3,4-dicarboxy) Eniru) -N- methylamine dianhydride, bis (3,4-carboxyphenyl) diethyl silane dianhydride, and the like.

Among them, the aromatic tetracarboxylic dianhydride is preferably a 2,2′-substituted biphenyltetracarboxylic dianhydride, more preferably 2,2′-bis (trihalomethyl) -4,4. ', 5,5'-biphenyltetracarboxylic dianhydride, more preferably 2,2'-bis (trifluoromethyl) -4,4', 5,5'-biphenyltetracarboxylic dianhydride It is.

Examples of the diamine include aromatic diamines, and specific examples include benzenediamine, diaminobenzophenone, naphthalenediamine, heterocyclic aromatic diamine, and other aromatic diamines.

Examples of the benzenediamine include o-, m- and p-phenylenediamine, 2,4-diaminotoluene, 1,4-diamino-2-methoxybenzene, 1,4-diamino-2-phenylbenzene and 1,1,4-diamino-2-methoxybenzene. And diamines selected from the group consisting of benzenediamines such as 3-diamino-4-chlorobenzene. Examples of the diaminobenzophenone include 2,2'-diaminobenzophenone and 3,3'-diaminobenzophenone. Examples of the naphthalenediamine include 1,8-diaminonaphthalene and 1,5-diaminonaphthalene. Examples of the heterocyclic aromatic diamine include 2,6-diaminopyridine, 2,4-diaminopyridine, and 2,4-diamino-S-triazine.

Examples of the aromatic diamine include 4,4′-diaminobiphenyl, 4,4′-diaminodiphenylmethane, 4,4 ′-(9-fluorenylidene) -dianiline and 2,2′-bis ( (Trifluoromethyl) -4,4'-diaminobiphenyl, 3,3'-dichloro-4,4'-diaminodiphenylmethane, 2,2'-dichloro-4,4'-diaminobiphenyl, 2,2 ', 5, 5'-tetrachlorobenzidine, 2,2-bis (4-aminophenoxyphenyl) propane, 2,2-bis (4-aminophenyl) propane, 2,2-bis (4-aminophenyl) -1,1, 1,3,3,3-hexafluoropropane, 4,4′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, 1,3-bis (3-aminophenoxy) benzene, 1,3-bis (4-amino Phenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 4 , 4'-bis (4-aminophenoxy) biphenyl, 4,4'-bis (3-aminophenoxy) biphenyl, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl] -1,1,1,1,3,3,3-hexafluoropropane, 4,4′-diaminodiphenylthioether, 4,4′-diaminodiphenylsulfone and the like.

と し て As the polyether ketone, for example, a polyaryl ether ketone represented by the following general formula (7) described in JP-A-2001-49110 is exemplified.

　前記式（７）中、Ｘは、置換基を表し、ｑは、その置換数を表す。Ｘは、例えば、ハロゲン原子、低級アルキル基、ハロゲン化アルキル基、低級アルコキシ基、または、ハロゲン化アルコキシ基であり、Ｘが複数の場合、それぞれ同一であるかまたは異なる。

In the formula (7), X represents a substituent, and q represents the number of the substituents. X is, for example, a halogen atom, a lower alkyl group, a halogenated alkyl group, a lower alkoxy group, or a halogenated alkoxy group. When a plurality of Xs are present, they are the same or different.

Examples of the halogen atom include a fluorine atom, a bromine atom, a chlorine atom and an iodine atom, and among these, a fluorine atom is preferable. The lower alkyl group is, for example, preferably a C1-6 linear or branched lower alkyl group, and more preferably a C1-4 linear or branched alkyl group. Specifically, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, and a tert-butyl group are preferable, and a methyl group and an ethyl group are particularly preferable. Examples of the halogenated alkyl group include a halide of the lower alkyl group such as a trifluoromethyl group. As the lower alkoxy group, for example, a C1-6 linear or branched alkoxy group is preferable, and a C1-4 linear or branched alkoxy group is more preferable. Specifically, a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, an isobutoxy group, a sec-butoxy group, and a tert-butoxy group are more preferable, and a methoxy group and an ethoxy group are particularly preferable. . Examples of the halogenated alkoxy group include a halide of the lower alkoxy group such as a trifluoromethoxy group.

Ｑ In the above formula (7), q is an integer from 0 to 4. In the above formula (7), it is preferable that q = 0 and that the carbonyl group bonded to both ends of the benzene ring and the oxygen atom of the ether be present at the para position to each other.

In the formula (7), R1 is a group represented by the following formula (8), and m is an integer of 0 or 1.

　前記式（８）中、Ｘ’は置換基を表し、例えば、前記式（７）におけるＸと同様である。前記式（８）において、Ｘ'が複数の場合、それぞれ同一であるかまたは異なる。ｑ'は、前記Ｘ'の置換数を表し、０から４までの整数であって、ｑ'＝０が好ましい。また、ｐは、０または１の整数である。

In the formula (8), X ′ represents a substituent, for example, the same as X in the formula (7). In the formula (8), when X ′ is plural, they are the same or different. q ′ represents the number of substitutions of X ′, is an integer from 0 to 4, and preferably q ′ = 0. P is an integer of 0 or 1.

中 In the formula (8), R2 represents a divalent aromatic group. Examples of the divalent aromatic group include an o-, m- or p-phenylene group, or naphthalene, biphenyl, anthracene, o-, m- or p-terphenyl, phenanthrene, dibenzofuran, biphenyl ether, or And a divalent group derived from biphenylsulfone. In these divalent aromatic groups, hydrogen directly bonded to the aromatic may be substituted with a halogen atom, a lower alkyl group or a lower alkoxy group. Among these, as R2, an aromatic group selected from the group consisting of the following formulas (9) to (15) is preferable.

　前記式（７）中、前記Ｒ¹としては、下記式（１６）で表される基が好ましく、下記式（１６）において、Ｒ²およびｐは前記式（８）と同義である。

In the formula (7), R ¹ is preferably a group represented by the following formula (16). In the following formula (16), R ² and p have the same meanings as in the formula (8).

　さらに、前記式（７）中、ｎは重合度を表し、例えば、２〜５０００の範囲であり、好ましくは、５〜５００の範囲である。また、その重合は、同じ構造の繰り返し単位からなるものであってもよく、異なる構造の繰り返し単位からなるものであってもよい。後者の場合には、繰り返し単位の重合形態は、ブロック重合であってもよいし、ランダム重合でもよい。

Further, in the above formula (7), n represents the degree of polymerization, and is, for example, in the range of 2 to 5000, preferably in the range of 5 to 500. The polymerization may be composed of repeating units having the same structure, or may be composed of repeating units having different structures. In the latter case, the polymerization form of the repeating unit may be block polymerization or random polymerization.

Further, the terminal of the polyaryl ether ketone represented by the above formula (7) is preferably such that the p-tetrafluorobenzoylene group side is fluorine and the oxyalkylene group side is a hydrogen atom. For example, it can be represented by the following general formula (17). In the following formula, n represents the same degree of polymerization as in the formula (7).

　前記式（７）で示されるポリアリールエーテルケトンの具体例としては、下記式（１８）〜（２１）で表されるもの等があげられ、下記各式において、ｎは、前記式（７）と同様の重合度を表す。

Specific examples of the polyaryl ether ketone represented by the formula (7) include those represented by the following formulas (18) to (21). In each of the following formulas, n is the same as the formula (7) Represents the same degree of polymerization.

　また、これらの他に、前記ポリアミドまたはポリエステルとしては、例えば、特表平１０−５０８０４８号公報に記載されるポリアミドやポリエステルがあげられ、それらの繰り返し単位は、例えば、下記一般式（２２）で表すことができる。

In addition to the above, examples of the polyamide or polyester include polyamides and polyesters described in JP-T-10-508048. The repeating unit thereof is, for example, a compound represented by the following general formula (22). Can be represented.

　前記式（２２）中、Ｙは、ＯまたはＮＨである。また、Ｅは、例えば、共有結合、Ｃ２アルキレン基、ハロゲン化Ｃ２アルキレン基、ＣＨ₂基、Ｃ(ＣＸ₃)₂基（ここで、Ｘはハロゲンまたは水素である。）、ＣＯ基、Ｏ原子、Ｓ原子、ＳＯ₂基、Ｓｉ(Ｒ)₂基、および、Ｎ(Ｒ)基からなる群から選ばれる少なくとも一種類の基であり、それぞれ同一でもよいし異なってもよい。前記Ｅにおいて、Ｒは、Ｃ１-３アルキル基およびＣ１-３ハロゲン化アルキル基の少なくとも一種類であり、カルボニル官能基またはＹ基に対してメタ位またはパラ位にある。

In the above formula (22), Y is O or NH. Further, E is, for example, covalent bond, C2 alkylene group, a halogenated C2 alkylene group, CH ₂ group, C (CX _{3) 2} group (wherein, X is halogen or hydrogen.), CO group, O atoms , S atom, SO ₂ group, Si (R) ₂ group, and N (R) group, and may be the same or different. In the above E, R is at least one of a C1-3 alkyl group and a C1-3 halogenated alkyl group, and is at a meta or para position with respect to the carbonyl functional group or the Y group.

In addition, in the above (22), A and A ′ are substituents, and t and z represent the respective numbers of substitution. Also, p is an integer from 0 to 3, q is an integer from 1 to 3, and r is an integer from 0 to 3.

A is, for example, hydrogen, halogen, a C1-3 alkyl group, a C1-3 halogenated alkyl group, an alkoxy group represented by OR (where R is as defined above), an aryl group, A substituted aryl group by halogenation or the like, a C1-9 alkoxycarbonyl group, a C1-9 alkylcarbonyloxy group, a C1-12 aryloxycarbonyl group, a C1-12 arylcarbonyloxy group and a substituted derivative thereof, a C1-12 arylcarbamoyl group, And a group selected from the group consisting of a C1-12 arylcarbonylamino group and a substituted derivative thereof. In a plurality of cases, each is the same or different. A ′ is selected from the group consisting of, for example, a halogen, a C1-3 alkyl group, a C1-3 halogenated alkyl group, a phenyl group and a substituted phenyl group, and in the case of a plurality, A ′ is the same or different. Examples of the substituent on the phenyl ring of the substituted phenyl group include a halogen, a C1-3 alkyl group, a C1-3 halogenated alkyl group, and a combination thereof. The t is an integer from 0 to 4, and the z is an integer from 0 to 3.

中 で も Among the polyamide or polyester repeating units represented by the above formula (22), those represented by the following general formula (23) are preferable.

　前記式（２３）中、Ａ、Ａ'およびＹは、前記式（２２）で定義したものであり、ｖは０から３の整数、好ましくは、０から２の整数である。ｘおよびｙは、それぞれ０または１であるが、共に０であることはない。

In the formula (23), A, A ′ and Y are as defined in the formula (22), and v is an integer from 0 to 3, preferably an integer from 0 to 2. x and y are each 0 or 1, but not both 0.

Next, as described above, the transparent polymer film has an in-plane retardation (Δnd) of 50 nm or less, preferably 20 nm or less, and more preferably 10 nm or less. In the present invention, the in-plane retardation (Δnd), the thickness direction retardation (Rth), and the birefringence (Δn) are represented by the following equations. When the transparent polymer film is a single layer, the lower limit of the in-plane retardation (Δnd) is a value exceeding 0. Accordingly, the range of the in-plane retardation (Δnd) of the transparent polymer film is preferably in the range of 50 nm or more and more than 0 nm, more preferably in the range of 20 nm or more and more than 0 nm, and further preferably in the range of 10 nm or more and more than 0 nm. is there. In the following formula, nx, ny and nz are the same as in the case of the above-described birefringent layer. That is, ny and nz indicate the refractive indexes of the transparent polymer film in the X-axis direction, the Y-axis direction, and the Z-axis direction, respectively. The X-axis direction is an axial direction indicating the maximum refractive index in the in-plane direction of the transparent polymer film, and the Y-axis direction is an axial direction perpendicular to the X-axis direction in the plane. , The Z-axis direction indicates a thickness direction perpendicular to the X-axis direction and the Y-axis direction. d is the thickness of the film.
Δnd = (nx−ny) · d
Rth = [(nx + ny) / 2-nz] · d
Δn = [(nx + ny) / 2-nz] · d / d
The material for forming the transparent polymer film is not particularly limited, and a polymer having excellent transparency is preferable, and a thermoplastic resin is preferable because it is suitable for a stretching process and a shrinking process described later. Specifically, for example, acetate resin such as triacetyl cellulose (TAC), polyester resin, polyether sulfone resin, polysulfone resin, polycarbonate resin, polyamide resin, polyimide resin, polyolefin resin, acrylic resin, polynorbornene resin (for example, Trade name "ARTON" (manufactured by JSR Corporation), trade name "ZEONOR", trade name "ZEONEX" (manufactured by Zeon Corporation), cellulose resin, polyarylate resin, polystyrene resin, polyvinyl alcohol resin, polyvinyl chloride resin, Examples include polyvinylidene chloride resin, polyacryl resin, and mixtures thereof. Further, a liquid crystal polymer or the like can be used. Further, for example, a thermoplastic resin having a substituted imide group or an unsubstituted imide group in a side chain and a substituted phenyl group in a side chain as described in JP-A-2001-343529 (WO 01/37007). Alternatively, a mixture of a thermoplastic resin having an unsubstituted phenyl group and a nitrile group can be used. Specific examples include, for example, a resin composition having an alternating copolymer of isobutene and N-methylenemaleimide and an acrylonitrile / styrene copolymer. Among these forming materials, for example, a material that can set the birefringence when forming a transparent film to a relatively lower value is preferable. Specifically, a substituted imide group or an unsubstituted imide group And a thermoplastic resin having a substituted or unsubstituted phenyl group and a nitrile group in the side chain. Representative examples of the above resins include cellulose-based polymer films such as triacetyl cellulose (TAC) and norbornene-based polymer films (“ARTON” (JSR), “ZEONOR”, “ZEONEX” (Nippon Zeon), etc.). No.

透明 The thickness of the transparent polymer film is, for example, about 10 to 1000 µm, preferably 20 to 500 µm, and more preferably 30 to 100 µm.

The transparent polymer film layer of the present invention may be formed in advance using the transparent polymer film having an in-plane retardation (Δnd) of the present invention, or may be formed of a transparent polymer film outside the above-mentioned predetermined range. May be subjected to a process such as stretching or shrinking to make the predetermined range.

Next, a solution of the non-liquid crystal polymer is applied to the transparent polymer film in a film form, and the solvent in the solution is removed by evaporation to form a birefringent layer.

The solvent of the solution to be applied is not particularly limited, and examples thereof include halogenated hydrocarbons such as chloroform, dichloromethane, carbon tetrachloride, dichloroethane, tetrachloroethane, trichloroethylene, tetrachloroethylene, chlorobenzene, and orthodichlorobenzene; phenol and pallachlorophenol. Phenols such as benzene; toluene, xylene, methoxybenzene, aromatic hydrocarbons such as 1,2-dimethoxybenzene; acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, cyclopentanone, 2-pyrrolidone, N-methyl- Ketone solvents such as 2-pyrrolidone; ester solvents such as ethyl acetate and butyl acetate; t-butyl alcohol, glycerin, ethylene glycol, triethylene glycol, ethylene glycol monomer Alcohol solvents such as dimethyl ether, diethylene glycol dimethyl ether, propylene glycol, dipropylene glycol, 2-methyl-2,4-pentanediol; amide solvents such as dimethylformamide and dimethylacetamide; nitrile solvents such as acetonitrile and butyronitrile Ether solvents such as diethyl ether, dibutyl ether and tetrahydrofuran; and carbon disulfide, ethyl cellosolve, butyl cellosolve and the like. These solvents may be used alone or in combination of two or more.

The coating solution may further contain, for example, various additives such as a stabilizer, a plasticizer, and metals as needed.

The coating solution may contain another different resin. Examples of the other resin include various general-purpose resins, engineering plastics, thermoplastic resins, and thermosetting resins.

汎 用 Examples of the general-purpose resin include polyethylene (PE), polypropylene (PP), polystyrene (PS), polymethyl methacrylate (PMMA), ABS resin, and AS resin. Examples of the engineering plastic include polyacetate (POM), polycarbonate (PC), polyamide (PA: nylon), polyethylene terephthalate (PET), and polybutylene terephthalate (PBT). Examples of the thermoplastic resin include polyphenylene sulfide (PPS), polyether sulfone (PES), polyketone (PK), polyimide (PI), polycyclohexane dimethanol terephthalate (PCT), polyarylate (PAR), and liquid crystal polymer. (LCP) and the like. Examples of the thermosetting resin include an epoxy resin and a phenol novolak resin.

As described above, when the other resin or the like is compounded in the coating solution, the compounding amount is, for example, 0 to 50% by mass, and preferably 0 to 30% by mass based on the polymer material. is there.

溶液 Examples of the method of applying the solution include a spin coating method, a roll coating method, a flow coating method, a printing method, a dip coating method, a casting film forming method, a bar coating method, and a gravure printing method. Further, at the time of coating, a superposition method of a polymer layer can be adopted as necessary.

後 After coating, the solvent in the solution is evaporated and removed by, for example, natural drying, air drying, and heat drying (for example, 60 to 250 ° C.) to form a film-like birefringent layer. This birefringent layer satisfies the condition of the above formula (1). The thickness of the birefringent layer is not particularly limited, but is, for example, 0.1 to 50 μm, preferably 0.5 to 30 μm, and more preferably 0.5 to 30 μm, from the viewpoints of thinning of the liquid crystal display device, viewing angle compensation, and film homogeneity. Is in the range of 1 to 20 μm.

The birefringent layer of the present invention has optically uniaxial characteristics (nx = ny> nz) unless a process other than the layer forming step by removing the non-liquid crystalline polymer solution by solvent evaporation is performed. However, for example, if the following processing is performed, a difference in refractive index (nx> ny) can be provided in the plane, and optical biaxiality (nx> ny> nz) is obtained. As a method of giving a difference in the refractive index in the plane of the birefringent layer, for example, the following method is available. First, a transparent polymer film having in-plane shrinkage in one direction is used, and the solution is applied thereon and dried to form the film using the in-plane shrinkage of the transparent polymer film. The birefringent layer can have an in-plane refractive index difference. Also, by applying the solution on a transparent polymer film to which stress is applied in one direction, or by blowing air from one direction on the applied solution, by forming a birefringent layer, A difference in the refractive index can be provided in the plane. In addition, by applying the solution on a transparent polymer film having anisotropy to form a birefringent layer, a difference in refractive index can be given in a plane. Further, by forming the birefringent layer on the transparent polymer film layer and then stretching the laminate, a difference in the refractive index can be provided in the plane of the birefringent layer. Note that these methods may be combined.

An optical film in which the transparent polymer film layer and the birefringent layer formed of a non-liquid crystalline polymer are laminated in this manner, wherein the optical polymer film satisfies the condition of the above formula (1), and The optical film of the present invention in which the in-plane retardation of the layer is 50 nm or less is obtained. Note that the optical film of the present invention may be manufactured by another manufacturing method. For example, the optical film may be formed by forming the birefringent layer as a film in advance by a T-die extrusion method or the like, and attaching the film to a transparent polymer film. As the attaching means, for example, there is a method using an adhesive or an adhesive.

に お い て In the present invention, the birefringent layer may be formed on one surface of the transparent polymer film layer, or may be formed on both surfaces. Further, the birefringent layer may be a single layer, or may have a single forming material or a multi-layer structure of a plurality of forming materials.

光学 The optical film of the present invention preferably further has at least one of an adhesive layer and a pressure-sensitive adhesive layer. This facilitates adhesion between the optical film of the present invention and other members such as another optical layer and a liquid crystal cell, and can prevent peeling of the optical film of the present invention. Therefore, the adhesive layer and the pressure-sensitive adhesive layer are preferably laminated on the outermost layer of the optical film, and may be laminated on one outermost layer or on both outermost layers of the optical film.

The material of the adhesive layer is not particularly limited. For example, acrylic pressure-sensitive adhesives such as acrylic, vinyl alcohol-based, silicone-based, polyester-based, polyurethane-based, and polyether-based pressure-sensitive adhesives, and rubber-based pressure-sensitive adhesives Etc. can be used. Further, these materials may contain fine particles to form a layer exhibiting light diffusivity. Among these, for example, a material excellent in hygroscopicity and heat resistance is preferable. With such properties, for example, when used in a liquid crystal display device, foaming and peeling due to moisture absorption, deterioration in optical characteristics due to a difference in thermal expansion, and warpage of a liquid crystal cell can be prevented, and high quality and durability can be achieved. The display device is also excellent.

As described above, the optical film of the present invention may be used alone, or may be combined with other optical members as needed to provide a laminate for various optical uses. Specifically, it is useful as a member for optical compensation, particularly as a visual compensation member. The other optical member is not particularly limited, and examples thereof include a polarizer shown below.

偏光 The polarizing plate of the present invention is a laminated polarizing plate including an optical film and a polarizer, wherein the optical film is the optical film of the present invention.

構成 The configuration of such a polarizing plate is not particularly limited as long as it has the optical film of the present invention, and examples thereof include those shown in FIG. 1 or FIG. 1 and 2 are cross-sectional views each showing an example of the polarizing plate of the present invention, and the same parts are denoted by the same reference numerals in both figures. Note that the polarizing plate of the present invention is not limited to the following configuration, and may further include other optical members and the like.

The polarizing plate shown in FIG. 1 has the optical film 1, the polarizer 2, and the transparent protective layer 3 of the present invention, and the optical film 1 is laminated on one surface (the upper surface in the drawing) of the polarizer 2, The transparent protective layer 3 is laminated on the other surface (the lower surface in the figure). Since the optical film 1 is a laminate of the birefringent layer and the transparent polymer film layer as described above, any surface may face the polarizer 2, but the transparent polymer film layer When the transparent protective layer 3 is also used, the transparent polymer film layer is preferably in contact with the polarizer. Further, the optical film 1, the polarizer 2, and the transparent protective layer 3 may be laminated by forming an adhesive layer or an adhesive layer between the respective layers.

The polarizing plate shown in FIG. 2 has the optical film 1, the polarizer 2, and two transparent protective layers 3 of the present invention. The transparent protective layers 3 are laminated on both surfaces of the polarizer 2, respectively. The optical film 1 is further laminated on the protective layer 3. Since the optical film 1 is a laminate of the birefringent layer and the transparent polymer film as described above, any surface may face the transparent protective layer 3.

The transparent protective layer may be laminated on both sides of the polarizer as shown in the figure, or may be laminated on only one of the surfaces. When laminating on both sides, for example, the same type of transparent protective layer may be used, or different types of transparent protective layers may be used.

The polarizer is not particularly limited, for example, by a conventionally known method, by adsorbing a dichroic substance such as iodine or a dichroic dye on various films, dyeing, crosslinking, stretching, and drying. Preparations and the like can be used. Among these, a film that transmits linearly polarized light when natural light is incident thereon is preferable, and a film that is excellent in light transmittance and polarization degree is preferable. Examples of the various films on which the dichroic substance is adsorbed include, for example, polyvinyl alcohol (PVA) -based films, partially formalized PVA-based films, ethylene-vinyl acetate copolymer-based partially saponified films, and cellulose-based films. Molecular films and the like, and besides these, for example, oriented polyene films such as dehydrated PVA and dehydrochlorinated polyvinyl chloride can also be used. Among these, a PVA-based film is preferred. The thickness of the polarizing film is usually in the range of 1 to 80 μm, but is not limited thereto.

透明 The transparent protective layer is not particularly limited, and a conventionally known transparent film can be used. For example, a layer having excellent transparency, mechanical strength, heat stability, moisture barrier properties, isotropy, and the like is preferable. Specific examples of the material of such a transparent protective layer include cellulosic resins such as triacetyl cellulose, and polyester, polycarbonate, polyamide, polyimide, polyethersulfone, polysulfone, polystyrene, and polynorbornene. And polyolefin-based, acrylic, and acetate-based transparent resins. Further, there may be mentioned a thermosetting resin such as acrylic, urethane, acrylic urethane, epoxy and silicone, or an ultraviolet curable resin. Among them, a TAC film whose surface is saponified with an alkali or the like is preferable from the viewpoint of polarization characteristics and durability.

Further, as the transparent protective layer, a polymer film described in JP-A-2001-343529 (WO 01/37007) can be mentioned. As the polymer material, for example, a resin composition containing a thermoplastic resin having a substituted or unsubstituted imide group in a side chain and a thermoplastic resin having a substituted or unsubstituted phenyl group and a nitrile group in a side chain For example, a resin composition having an alternating copolymer of isobutene and N-methylenemaleimide and an acrylonitrile / styrene copolymer can be used. The polymer film may be, for example, an extruded product of the resin composition.

Further, it is preferable that the transparent protective layer has no coloring, for example. Specifically, the retardation value (Rth) in the film thickness direction represented by the following formula is preferably in the range of -90 nm to +75 nm, more preferably -80 nm to +60 nm, and particularly preferably -70 nm. ＋+ 45 nm. When the retardation value is in the range of -90 nm to +75 nm, coloring (optical coloring) of the polarizing plate caused by the protective film can be sufficiently eliminated. In the following formula, nx, ny, and nz are the same as described above, and d indicates the film thickness.
Rth = [(nx + ny) / 2-nz] · d
Further, the transparent protective layer may further have an optical compensation function. As described above, the transparent protective layer having an optical compensation function is, for example, for the purpose of preventing coloring or the like, or increasing the viewing angle for good visibility, due to a change in the viewing angle based on the phase difference in the liquid crystal cell. Known ones can be used. Specifically, for example, various stretched films obtained by uniaxially or biaxially stretching the transparent resin described above, an alignment film such as a liquid crystal polymer, and a laminate in which an alignment layer such as a liquid crystal polymer is disposed on a transparent base material are exemplified. Can be Among these, an alignment film of the liquid crystal polymer is preferable because a wide viewing angle with good visibility can be achieved.In particular, the optical compensation layer composed of a tilted alignment layer of a discotic or nematic liquid crystal polymer, An optical compensation retardation plate supported by a triacetyl cellulose film or the like is preferable. Examples of such an optical compensation retardation plate include commercially available products such as “WV film” manufactured by Fuji Photo Film Co., Ltd. The optical compensation retardation plate may be one in which optical properties such as retardation are controlled by laminating two or more film supports such as the retardation film and the triacetyl cellulose film.

The thickness of the transparent protective layer is not particularly limited and can be appropriately determined depending on, for example, a retardation and a protection strength. However, the thickness is usually 500 μm or less, preferably 5 to 300 μm, and more preferably 5 to 150 μm. The transparent protective layer is, for example, by a conventionally known method such as a method of applying the various transparent resins to a polarizing film, a method of laminating the transparent resin film or the optical compensation retardation plate or the like on the polarizing film. It can be appropriately formed, and a commercially available product can also be used.

The transparent protective layer may be further subjected to, for example, a hard coat treatment, an antireflection treatment, a treatment for preventing sticking and diffusion, an antiglare, and the like. The hard coat treatment is for the purpose of preventing scratches on the surface of the polarizing plate and the like, for example, a process of forming a cured film made of a curable resin and having excellent hardness and slipperiness on the surface of the transparent protective layer. It is. As the curable resin, for example, an ultraviolet curable resin such as a silicone-based, urethane-based, acrylic-based, or epoxy-based resin can be used, and the treatment can be performed by a conventionally known method. The purpose of preventing sticking is to prevent adhesion between adjacent layers. The antireflection treatment is for preventing reflection of external light on the surface of the polarizing plate, and can be performed by forming a conventionally known antireflection layer or the like.

  The anti-glare treatment is for the purpose of preventing visible light obstruction of light transmitted through the polarizing plate due to reflection of external light on the surface of the polarizing plate, for example, by a conventionally known method, on the surface of the transparent protective layer, This can be performed by forming a fine uneven structure. Examples of the method of forming such a concavo-convex structure include a method of forming a surface by sandblasting or embossing, and a method of forming the transparent protective layer by blending transparent fine particles with the transparent resin as described above. Can be

Examples of the transparent fine particles include, for example, silica, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, antimony oxide, and the like.In addition, inorganic fine particles having conductivity, and crosslinked or uncrosslinked. Organic fine particles composed of polymer particles or the like can also be used. The average particle size of the transparent fine particles is not particularly limited, but is, for example, in the range of 0.5 to 20 μm. The mixing ratio of the transparent fine particles is not particularly limited, but is generally preferably in the range of 2 to 70 parts by mass, more preferably in the range of 5 to 50 parts by mass per 100 parts by mass of the transparent resin as described above.

The anti-glare layer containing the transparent fine particles can be used, for example, as the transparent protective layer itself, or may be formed as a coating layer on the surface of the transparent protective layer. Further, the anti-glare layer may also serve as a diffusion layer (a visual compensation function or the like) for diffusing light transmitted through the polarizing plate to increase the viewing angle.

  The anti-reflection layer, the anti-sticking layer, the diffusion layer, the anti-glare layer and the like are separately formed from the transparent protective layer, for example, as an optical layer composed of a sheet or the like provided with these layers, laminated on a polarizing plate. May be.

積 層 The method of laminating the components (optical film, polarizer, transparent protective layer, etc.) is not particularly limited, and can be performed by a conventionally known method. In general, the same pressure-sensitive adhesives and adhesives as described above can be used, and the type thereof can be appropriately determined depending on the material of each of the components. Examples of the adhesive include an acrylic adhesive, a vinyl alcohol adhesive, a silicone adhesive, a polyester adhesive, a polyurethane adhesive, a polyether adhesive, and the like, and a rubber adhesive. In addition, an adhesive composed of a water-soluble cross-linking agent of a vinyl alcohol-based polymer such as glutaraldehyde, melamine, and oxalic acid can also be used. The above-mentioned pressure-sensitive adhesives and adhesives are hardly peeled off even under the influence of humidity or heat, for example, and are excellent in light transmittance and polarization degree. Specifically, when the polarizer is a PVA-based film, for example, a PVA-based adhesive is preferable from the viewpoint of the stability of the bonding treatment and the like. These adhesives and pressure-sensitive adhesives, for example, may be directly applied to the surface of a polarizer or a transparent protective layer, or a layer such as a tape or sheet composed of the adhesive or pressure-sensitive adhesive is disposed on the surface. May be. Further, for example, when prepared as an aqueous solution, another additive or a catalyst such as an acid may be blended as necessary. When the adhesive is applied, for example, another additive or a catalyst such as an acid may be added to the aqueous solution of the adhesive. The thickness of such an adhesive layer is not particularly limited, but is, for example, 1 nm to 500 nm, preferably 10 nm to 300 nm, and more preferably 20 nm to 100 nm. There is no particular limitation, and for example, a conventionally known method using an adhesive such as an acrylic polymer or a vinyl alcohol polymer can be employed. Further, since it is hard to be peeled off even by humidity or heat and can form a polarizing plate having excellent light transmittance and polarization degree, an adhesive containing a water-soluble crosslinking agent of a PVA-based polymer such as glutaraldehyde, melamine, oxalic acid, etc. preferable. These adhesives can be used, for example, by applying an aqueous solution thereof to the surface of each of the above-mentioned components and drying the applied solution. In the aqueous solution, for example, other additives and a catalyst such as an acid can be blended, if necessary. Among these, a PVA-based adhesive is preferable as the adhesive from the viewpoint of excellent adhesion to a PVA film.

The optical film of the present invention can be used in combination with conventionally known optical members such as various retardation plates, diffusion control films, and brightness enhancement films, in addition to the polarizers described above. Examples of the retardation plate include those obtained by uniaxially or biaxially stretching a polymer film, those subjected to a Z-axis orientation treatment, and a liquid crystalline polymer coating film. Examples of the diffusion control film include a film utilizing diffusion, scattering, and refraction. These films can be used, for example, for controlling a viewing angle and controlling glare and scattered light related to resolution. As the brightness enhancement film, for example, a brightness enhancement film using selective reflection of cholesteric liquid crystal and a 波長 wavelength plate (λ / 4 plate), a scattering film using anisotropic scattering depending on a polarization direction, and the like are used. it can. Further, the optical film can be combined with, for example, a wire grid polarizer.

偏光 In practical use, the polarizing plate of the present invention may further include another optical layer in addition to the optical film of the present invention. Examples of the optical layer include conventionally known various optical layers used for forming a liquid crystal display device such as a polarizing plate, a reflecting plate, a semi-transmissive reflecting plate, and a brightness enhancement film as described below. One of these optical layers may be used, two or more of them may be used in combination, one layer may be used, or two or more layers may be laminated. The laminated polarizing plate further including such an optical layer is preferably used, for example, as an integrated polarizing plate having an optical compensation function, and is suitable for use in various image display devices, for example, disposed on a liquid crystal cell surface. ing.

Hereinafter, such an integrated polarizing plate will be described.

  First, an example of a reflective polarizing plate or a transflective polarizing plate will be described. In the reflective polarizing plate, a reflective plate is further laminated on the laminated polarizing plate of the present invention, and in the semi-transmissive reflective polarizing plate, a semi-transmissive reflective plate is further laminated on the laminated polarizing plate of the present invention.

The reflective polarizer is usually disposed on the back side of a liquid crystal cell, and can be used for a liquid crystal display device (reflective liquid crystal display device) that reflects incident light from the viewing side (display side) to display. Such a reflective polarizer can omit the incorporation of a light source such as a backlight, for example, and thus has advantages such as enabling the liquid crystal display device to be thinner.

  The reflective polarizing plate can be manufactured by a conventionally known method such as a method of forming a reflective plate made of metal or the like on one surface of the polarizing plate having the elastic modulus. Specifically, for example, one surface (exposed surface) of the transparent protective layer in the polarizing plate is subjected to a mat treatment as necessary, and a metal foil or a vapor-deposited film made of a reflective metal such as aluminum is coated on the surface. And the like.

  In addition, as described above, a reflective polarizing plate and the like, in which a reflective plate reflecting the fine uneven structure is formed on a transparent protective layer having a fine uneven structure on the surface by incorporating fine particles in various transparent resins as described above, may also be used. Can be A reflector having a fine uneven structure on its surface has an advantage that, for example, incident light is diffused by irregular reflection, directivity and glare can be prevented, and uneven brightness can be suppressed. Such a reflection plate, for example, on the uneven surface of the transparent protective layer, a vacuum deposition method, an ion plating method, a deposition method such as a sputtering method or a plating method, a conventionally known method, directly, the metal foil or It can be formed as a metal deposition film.

  Further, instead of a method in which the reflective plate is directly formed on the transparent protective layer of the polarizing plate as described above, a reflective sheet or the like provided with a reflective layer on an appropriate film such as the transparent protective film is used as the reflective plate. May be. Since the reflection layer in the reflection plate is usually made of metal, for example, to prevent a decrease in reflectance due to oxidation, and thus a long-lasting initial reflectance, and in order to avoid separately forming a transparent protective layer, It is preferable that the mode of use is such that the reflection surface of the reflection layer is covered with the film, the polarizing plate, or the like.

  On the other hand, the transflective polarizing plate has a transflective reflecting plate in place of the reflecting plate in the reflecting type polarizing plate. Examples of the semi-transmissive reflection plate include a half mirror that reflects light on a reflection layer and transmits light.

  The transflective polarizing plate is usually provided on the back side of a liquid crystal cell. When a liquid crystal display device or the like is used in a relatively bright atmosphere, it reflects incident light from the viewing side (display side) to form an image. In a relatively dark atmosphere for display, the present invention can be used for a liquid crystal display device or the like that displays images using a built-in light source such as a backlight built in the back side of a transflective polarizing plate. That is, the transflective polarizing plate can save energy for use of a light source such as a backlight in a bright atmosphere, and can be used with the built-in light source even in a relatively dark atmosphere. It is useful for formation of etc.

Next, an example of a polarizing plate in which a brightness enhancement film is further laminated on the polarizing plate of the present invention will be described.

  The brightness enhancement film is not particularly limited, for example, a multilayer thin film of a dielectric, such as a multilayer laminate of thin film having different refractive index anisotropy, transmitting linearly polarized light of a predetermined polarization axis, Other light that shows a characteristic of reflecting light can be used. As such a brightness enhancement film, for example, "D-BEF" (trade name, manufactured by 3M) is exemplified. In addition, a cholesteric liquid crystal layer, in particular, an oriented film of a cholesteric liquid crystal polymer, and a film in which the oriented liquid crystal layer is supported on a film substrate can be used. These reflect one of the left and right circularly polarized light and show the property of transmitting the other light. For example, Nitto Denko's product name "PCF350", Merck's product name "Transmax", etc. can give.

  The various polarizing plates of the present invention as described above may be, for example, optical members obtained by laminating the polarizing plate of the present invention and two or more optical layers.

  Such an optical member in which two or more optical layers are laminated can be formed, for example, in a manufacturing process of a liquid crystal display device or the like by a method in which the optical members are sequentially laminated separately. In addition, there is an advantage that it is excellent in quality stability, assembling workability, and the like, and can improve the manufacturing efficiency of a liquid crystal display device and the like. In addition, various bonding means, such as an adhesive layer, can be used for lamination similarly to the above.

  Various polarizing plates as described above preferably further have an adhesive layer or an adhesive layer, for example, because they can be easily laminated on another member such as a liquid crystal cell. It can be arranged on one or both sides of the board. The material of the pressure-sensitive adhesive layer is not particularly limited, and a conventionally known material such as an acrylic polymer can be used. In particular, prevention of foaming and peeling due to moisture absorption, deterioration of optical properties due to a difference in thermal expansion, and warpage of a liquid crystal cell can be used. For example, from the viewpoint of prevention, and, in turn, the formability of a liquid crystal display device having high quality and excellent durability, for example, it is preferable to form an adhesive layer having low moisture absorption and excellent heat resistance. Further, an adhesive layer containing fine particles and exhibiting light diffusing property may be used. Formation of the pressure-sensitive adhesive layer on the surface of the polarizing plate, for example, a solution or a melt of various pressure-sensitive adhesive materials, by a spreading method such as casting or coating, directly added to a predetermined surface of the polarizing plate, a layer Or a method in which a pressure-sensitive adhesive layer is formed on a separator to be described later and then transferred to a predetermined surface of the polarizing plate. In addition, such a layer may be formed on any surface of the polarizing plate, for example, may be formed on an exposed surface of the retardation plate in the polarizing plate.

  When the surface of the pressure-sensitive adhesive layer or the like provided on the polarizing plate is exposed as described above, it is preferable to cover the surface with a separator for the purpose of preventing contamination or the like until the pressure-sensitive adhesive layer is put to practical use. This separator is formed on a suitable film such as the transparent protective film or the like, if necessary, by a method of providing one or more release coats with a release agent such as a silicone-based, long-chain alkyl-based, fluorine-based, or molybdenum sulfide. it can.

The pressure-sensitive adhesive layer and the like may be, for example, a single-layer body or a laminate. As the laminate, for example, a laminate in which different compositions or different types of single layers are combined may be used. In the case of disposing the pressure-sensitive adhesive layers on both surfaces of the polarizing plate, for example, they may be the same pressure-sensitive adhesive layer, or may have different compositions or different types of pressure-sensitive adhesive layers.

  The thickness of the pressure-sensitive adhesive layer can be appropriately determined according to, for example, the configuration of the polarizing plate, and is generally 1 to 500 μm.

粘着 As the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer, for example, a pressure-sensitive adhesive excellent in optical transparency and exhibiting appropriate wettability, cohesiveness and adhesiveness is preferable. Specific examples include pressure-sensitive adhesives prepared by appropriately using polymers such as acrylic polymers, silicone polymers, polyesters, polyurethanes, polyethers, and synthetic rubbers as base polymers.

Control of the adhesive properties of the pressure-sensitive adhesive layer, for example, the composition and molecular weight of the base polymer forming the pressure-sensitive adhesive layer, the crosslinking method, the content of the crosslinking functional group, the mixing ratio of the crosslinking agent, the degree of crosslinking, It can be appropriately performed by a conventionally known method such as adjusting the molecular weight.

  Each layer such as the optical film and the polarizing plate of the present invention as described above, the polarizing film, the transparent protective layer, the optical layer, and the pressure-sensitive adhesive layer which form various optical members (various polarizing plates in which optical layers are laminated) is formed of, for example, salicylic acid. A compound having an ultraviolet absorbing property by appropriately treating with an ultraviolet absorbing agent such as an ester compound, a benzophenone compound, a benzotriazole compound, a cyanoacrylate compound, or a nickel complex compound may be used.

  As described above, the optical film and the polarizing plate of the present invention are preferably used for forming various devices such as a liquid crystal display device.For example, the optical film and the polarizing plate of the present invention are arranged on one side or both sides of a liquid crystal cell. Thus, the liquid crystal panel can be used for a liquid crystal display device of a reflection type, a transflective type, or a transmission / reflection type.

The type of the liquid crystal cell forming the liquid crystal display device can be arbitrarily selected. For example, an STN (Super Twisted Nematic) cell, a TN (Twisted Nematic) cell, an IPS (In-Plane Switching) cell, a VA (Vertical Alighned) cell , OCB (Optically Alighned Birefringence) cells, HAN (Hybrid Alighned Nematic) cells, ASM (Axially Symmetric Alighned Microcell) cells, ferroelectric / anti-ferroelectric cells, and those obtained by performing regular orientation division on these, and performing random orientation division. Various types of cells such as objects are included. Among them, the optical film and the polarizing plate of the present invention are very excellent especially in optical compensation of VA cells and OCB cells, and thus are very useful as viewing angle compensation films for VA mode and OCB mode liquid crystal display devices. is there.

The liquid crystal cell usually has a structure in which liquid crystal is injected into a gap between opposing liquid crystal cell substrates. The liquid crystal cell substrate is not particularly limited, and for example, a glass substrate or a plastic substrate can be used. The material of the plastic substrate is not particularly limited, and may be a conventionally known material.

  When polarizing plates or optical members are provided on both surfaces of the liquid crystal cell, they may be of the same type or different. Further, in forming the liquid crystal display device, for example, one or more layers of appropriate parts such as a prism array sheet, a lens array sheet, a light diffusion plate, and a backlight can be arranged at appropriate positions.

Furthermore, the liquid crystal display device of the present invention includes a liquid crystal panel, and is not particularly limited except that the liquid crystal panel of the present invention is used as the liquid crystal panel. When a light source is included, the light source is not particularly limited. For example, a planar light source that emits polarized light is preferable because light energy can be used effectively.

(3) An example of the liquid crystal panel of the present invention is shown in the sectional view of FIG. As shown in the drawing, the liquid crystal panel has a liquid crystal cell 21, an optical film 1, a polarizer 2, and a transparent protective layer 3. The optical film 1 is laminated on one surface of the liquid crystal cell 21, and an optical On the other surface, the polarizer 2 and the transparent protective layer are laminated in this order. The liquid crystal cell has a configuration in which liquid crystal is held between two liquid crystal cell substrates (not shown). The optical film 1 is a laminate of a birefringent layer and a transparent polymer film layer as described above. The birefringent layer side faces the liquid crystal cell 21 and the transparent polymer film side faces the polarizer 2. are doing.

  The liquid crystal display device of the present invention may further include, for example, disposing a diffusion plate, an antiglare layer, an antireflection film, a protective layer or a protective plate on the optical film (polarizing plate) on the viewing side, or a liquid crystal cell in a liquid crystal panel. A compensating retardation plate or the like may be appropriately disposed between the polarizing plate and the polarizing plate.

The optical film and the polarizing plate of the present invention are not limited to the liquid crystal display device described above, and can be used for a self-luminous display device such as an organic electroluminescence (EL) display, PDP, and FED. When used in a self-luminous flat display, for example, by setting the in-plane retardation value Δnd of the birefringent optical film of the present invention to λ / 4, circularly polarized light can be obtained. Available.

Hereinafter, an electroluminescence (EL) display device including the polarizing plate of the present invention will be described. The EL display device of the present invention is a display device having the optical film or the polarizing plate of the present invention, and the EL device may be any of an organic EL and an inorganic EL.

In recent years, in an EL display device, it has been proposed to use an optical film such as a polarizer or a polarizing plate together with a λ / 4 plate to prevent reflection from an electrode in a black state. The polarizer or the optical film of the present invention is particularly suitable for the case where any one of linearly polarized light, circularly polarized light or elliptically polarized light is emitted from the EL layer, or even when natural light is emitted in the front direction, This is very useful when the emitted light in the direction is partially polarized.

First, a general organic EL display device will be described. The organic EL display device generally has a light-emitting body (organic EL light-emitting body) in which a transparent electrode, an organic light-emitting layer, and a metal electrode are stacked in this order on a transparent substrate. The organic light emitting layer is a laminate of various organic thin films, for example, a laminate of a hole injection layer made of a triphenylamine derivative or the like and a light emitting layer made of a fluorescent organic solid such as anthracene, Various combinations such as a stacked body of a light emitting layer and an electron injection layer made of a perylene derivative or the like, and a stacked body of the hole injection layer, the light emitting layer, and the electron injection layer are given.

  In such an organic EL display device, by applying a voltage to the anode and the cathode, holes and electrons are injected into the organic light emitting layer, and the holes and electrons are recombined. The emitted energy emits light on the principle that it excites the phosphor and emits light when the excited phosphor returns to the ground state. The mechanism of the recombination of holes and electrons is the same as that of a general diode, and the current and the emission intensity show strong nonlinearity with rectification with respect to the applied voltage.

In the organic EL display device, at least one electrode is required to be transparent in order to extract light emitted from the organic light emitting layer. Therefore, the organic EL display device is usually formed of a transparent conductor such as indium tin oxide (ITO). A transparent electrode is used as the anode. On the other hand, in order to facilitate electron injection and increase luminous efficiency, it is important to use a material having a small work function for the cathode, and usually a metal electrode such as Mg-Ag or Al-Li is used.

In the organic EL display device having such a configuration, it is preferable that the organic light emitting layer is formed of, for example, an extremely thin film having a thickness of about 10 nm. This is because light is transmitted almost completely in the organic light emitting layer as in the case of the transparent electrode. As a result, when light is not emitted, light that enters from the surface of the transparent substrate, passes through the transparent electrode and the organic light emitting layer, and is reflected by the metal electrode exits to the surface of the transparent substrate again. Therefore, when viewed from the outside, the display surface of the organic EL display device looks like a mirror surface.

  The organic EL display device of the present invention includes, for example, an organic EL display device including a transparent electrode on a front surface side of the organic light emitting layer and the organic EL light emitting body including a metal electrode on a back surface side of the organic light emitting layer. The optical film of the present invention (such as a polarizing plate) is preferably disposed on the surface of the transparent electrode, and a λ / 4 plate is preferably disposed between the polarizing plate and the EL element. Thus, by arranging the optical film of the present invention, an organic EL display device has an effect of suppressing reflection of the outside world and improving visibility. Further, it is preferable that a retardation plate is further disposed between the transparent electrode and the optical film.

  Since the retardation plate and the optical film (such as a polarizing plate) have a function of, for example, polarizing light incident from the outside and reflected by the metal electrode, the mirror effect of the metal electrode is visually recognized by the polarizing function. It has the effect of not letting it. In particular, if a quarter-wave plate is used as the phase difference plate and the angle between the polarization direction of the polarizing plate and the phase difference plate is adjusted to π / 4, the mirror surface of the metal electrode is completely shielded. can do. That is, only linearly polarized light components of the external light incident on the organic EL display device are transmitted by the polarizing plate. The linearly polarized light is generally converted into elliptically polarized light by the retardation plate. In particular, when the retardation plate is a quarter-wave plate and the angle is π / 4, the linearly polarized light becomes circularly polarized light.

This circularly polarized light, for example, passes through a transparent substrate, a transparent electrode, an organic thin film, is reflected by a metal electrode, again passes through an organic thin film, a transparent electrode, a transparent substrate, and is again linearly polarized by the retardation plate. Become. And, since this linearly polarized light is orthogonal to the polarization direction of the polarizing plate, it cannot pass through the polarizing plate, and as a result, the mirror surface of the metal electrode can be completely shielded as described above. .

Next, examples of the present invention will be described together with comparative examples. However, the present invention is not limited to the following embodiments. In the following examples, the characteristics of the optical films were evaluated by the following methods.

(Measurement of phase difference value Δnd and alignment axis accuracy)
The phase difference value Δnd and the orientation axis accuracy were measured using a phase difference meter (trade name: KOBRA21ADH, manufactured by Oji Scientific Instruments).

(Measurement of refractive index)
The refractive index was measured at 590 nm using KOBRA21ADH (trade name, manufactured by Oji Scientific Instruments).

(Film thickness measurement)
The film thickness was measured using a digital micrometer model K-351C manufactured by Anritsu.

Weight average molecular weight synthesized from 2,2'-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride and 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl Polyimide having a (Mw) of 70,000 and a birefringence (Δn) of about 0.04 was dissolved in MIBK (methyl isobutyl ketone) to obtain a solution having a solid content of 15% by weight. This solution was applied on a 75 μm-thick triacetylcellulose (TAC) film that had been stretched 1.3 times at 150 ° C. by fixed-end transverse stretching. Δnd of this TAC film was 20 nm. Thereafter, by heating at 100 ° C. for 10 minutes, the solvent was removed by evaporation of the solution to form a layer, and the layer was shrunk by shrinking the TAC film to obtain a completely transparent and smooth optical film. . The optical characteristics of the obtained birefringent layer were such that nx> ny> nz.

75 parts by weight of an alternating copolymer of isobutene and N-methylmaleimide (N-methylmaleimide content: 50 mol%) and 25 parts by weight of an acrylonitrile-styrene copolymer having an acrylonitrile content of 28% by weight were added to methylene chloride. After dissolution, a solution having a solid content of 15% by weight was obtained. The solution was cast on a polyethylene terephthalate (PET) film spread on a glass plate, left at room temperature for 60 minutes, peeled off the PET film, dried at 100 ° C. for 10 minutes, dried at 140 ° C. for 10 minutes, and further heated at 160 ° C. For 30 minutes to obtain a transparent film. The in-plane retardation (△ nd) of the film was 4 nm, and Rth was 4 nm.

溶液 The same solution as in Example 1 was applied to the transparent film obtained as described above. Thereafter, a layer was formed on the transparent film by heating at 100 ° C. for 5 minutes to obtain a completely transparent and smooth film. The obtained film was subjected to 10% longitudinal uniaxial stretching at a temperature of 130 ° C to obtain an optical film. The optical characteristics of the birefringent layer of the obtained optical film satisfy nx> ny> nz.

Birefringence synthesized from 2,2'-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride and 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl (Δn) About 0.05 polyimide was dissolved in ethyl acetate to obtain a solution having a solid content of 20% by weight. This solution was applied on the substrate used in Example 1. Thereafter, by heating at 130 ° C. for 5 minutes, the solvent was removed by evaporation of the solvent to form a layer, and the layer was contracted to obtain a completely transparent and smooth optical film. The optical characteristics of the birefringent layer of the obtained optical film satisfy nx> ny> nz.

Polyetherketone (polyaryletherketone A, manufactured by Nippon Shokubai Co., Ltd.) represented by the following structural formula (18) and having a birefringence (Δn) of about 0.03 was dissolved in MIBK to obtain a solid content of 20% by weight. A solution was prepared. This was applied to a 75 μm-thick triacetylcellulose (TAC) film that was 1.3 times laterally stretched at 130 ° C. by fixed-end lateral stretching. Δnd of this TAC film was 15 nm. Thereafter, the solution was subjected to heat treatment at 100 ° C. for 10 minutes to remove the solvent by evaporation to form a layer, and the layer was subjected to shrinkage treatment to obtain a completely transparent and smooth optical film. The optical characteristics of the birefringent layer of the obtained optical film satisfy nx> ny> nz.

溶液 Using the same solution as in Example 1, this solution was applied on a triacetyl cellulose (TAC) film having a thickness of 80 μm. Δnd of this TAC film was 5 nm. Thereafter, the solution was subjected to a heat treatment at 100 ° C. for 10 minutes to remove the solvent by evaporation to form a layer, thereby obtaining a completely transparent and smooth film. This film was stretched 10% longitudinally and uniaxially at a temperature of 150 ° C. to cause a difference in the refractive index in the plane of the layer to obtain an optical film. The optical characteristics of the birefringent layer of the obtained optical film satisfy nx> ny> nz.

溶液 Using the same solution as in Example 1, this solution was applied on a triacetyl cellulose (TAC) film having a thickness of 80 μm. Δnd of this TAC film was 5 nm. Thereafter, the solution was subjected to a heat treatment at 100 ° C. for 10 minutes to remove the solvent by evaporation to form a birefringent layer, thereby obtaining a completely transparent and smooth optical film. The optical characteristics of the birefringent layer of the obtained optical film satisfy nx = ny> nz.

Weight average molecular weight (4,4′-bis (3,4-dicarboxyphenyl) -2,2-diphenylpropane dianhydride and 2,2′-dichloro-4,4′-diaminobiphenyl) Mw) 30,000 polyimides were dissolved in cyclopentanone to obtain a solution having a solid concentration of 20% by weight. This solution was applied on a TAC film that had been treated in the same manner as in Example 1. Thereafter, the solution was subjected to a heat treatment at 140 ° C. for 10 minutes to evaporate and remove the solvent from the solution to form a layer, and the layer was contracted to obtain a completely transparent and smooth optical film. The optical characteristics of the birefringent layer of the obtained optical film satisfy nx> ny> nz.

Comparative Example 1

用 い Using the same solution as in Example 1, this solution was applied on a PET film having a thickness of 75 μm and △ nd = 4000 nm. Thereafter, the solution was subjected to heat treatment at 150 ° C. for 10 minutes to remove the solvent by evaporation to form a birefringent layer, thereby obtaining a completely transparent and smooth optical film. The birefringent layer of this optical film had optical characteristics of nx = ny> nz. However, since the in-plane retardation of the PET film is too large, there is a problem in the optical characteristics of the optical film, and it is necessary to peel the birefringent layer from the PET film and transfer it to an optical member such as a polarizer before use. Was.

Comparative Example 2

(4) The same solution as in Example 1 was applied on a 150 μm-thick TAC film that was stretched 1.5 times in the free-end longitudinal direction at 150 ° C. Δnd of this TAC film was 70 nm. Thereafter, the solution was subjected to heat treatment at 100 ° C. for 10 minutes to remove the solvent by evaporation to form a birefringent layer, thereby obtaining a completely transparent and smooth optical film. The birefringent layer of this optical film had optical characteristics of nx = ny> nz. However, since the in-plane retardation of the PET film is too large, there is a problem in the optical characteristics of the optical film, and it is necessary to peel the birefringent layer from the PET film and transfer it to an optical member such as a polarizer before use. Was.

Regarding the optical films obtained in the above Examples and Comparative Examples, the thickness, the in-plane retardation A (Δnd) of the optical film, the in-plane retardation B (Δnd) of the transparent polymer film, and the birefringence of the birefringent layer were obtained. The results obtained by examining the refractive index (Δn (a)) and the birefringence (Δn (b)) of the transparent polymer film are shown in Table 1 below.
(Table 1)
Thickness (μm) A (Δnd) B (Δnd) Δn (a) Δn (b)
Example 1 6 135 20 0.04 0.0006
Example 2 6 120 4 0.04 0.001
Example 3 10 70 20 0.05 0.0006
Example 4 10 80 15 0.03 0.0006
Example 5 8 150 20 0.04 0.0006
Example 6 6 0.3 5 0.04 0.0006
Example 7 6 130 20 0.025 0.0006
Comparative Example 1 6 0.9 4000 0.04 0.08
Comparative Example 2 6 150 70 0.04 0.0007

The optical films obtained in the above Examples and Comparative Examples were examined for liquid crystal display characteristics (LCD display characteristics). That is, first, an optical film and a polarizing plate (trade name “HEG1425DU” manufactured by Nitto Denko Corporation) were laminated via an acrylic adhesive to obtain a polarizing plate integrated with an optical compensation layer. This was adhered to the backlight side of the liquid crystal cell so that the polarizing plate was on the outside, to produce a liquid crystal display device. Then, the front contrast of the liquid crystal display device was examined. The results are shown in Table 2 below. Further, in Example 1 and Comparative Example 1, the presence or absence of occurrence of rainbow unevenness was examined. The results are shown in the photographs of FIG. 5 (Example 1) and FIG. 6 (Comparative Example 1). The front contrast was measured by the following method.
(Front contrast)
A white image and a black image were displayed on the liquid crystal display device, and the Y value, the x value, and the y value of the XYZ display system in front of the display screen were measured by Ez contrast 160D (trade name, manufactured by ELDIM). Then, the front (0 ° viewing angle) contrast (Y _W / Y _B ) was calculated from the Y value (Y _W ) of the white image and the Y value (Y _B ) of the black image.

(Table 2)
Front contrast ^* 　
Example 1 ○
Example 2 ○
Example 3 ○
Example 4 ○
Example 5 ○
Example 6 ○
Example 7 ○
Comparative Example 1 ×
Comparative Example 2 ×

* A contrast of 100 or more was evaluated as ○ and a contrast of less than 100 was evaluated as ×.

As shown in Table 1, all the examples were excellent in contrast. On the other hand, the comparative example had a problem in contrast. Further, as shown in FIG. 5, in Example 1, no rainbow unevenness occurred. On the other hand, as shown in FIG. 6, in Comparative Example 1, rainbow unevenness occurred.

As described above, the optical film of the present invention has excellent optical properties and can be manufactured easily and at low cost. Therefore, the optical film of the present invention is useful, for example, as an optical member of a display device such as a liquid crystal display device or a self-luminous display device.

FIG. 2 is a schematic cross-sectional view illustrating an example of the polarizing plate of the present invention. FIG. 4 is a schematic cross-sectional view showing another example of the polarizing plate of the present invention. It is a cross section showing an example of the liquid crystal display of the present invention. It is a figure showing an example of an axial direction of an optical film of the present invention. It is the photograph which evaluated rainbow unevenness in one Example of the optical film of this invention. It is the photograph which evaluated the rainbow unevenness in the optical film of the comparative example.

Explanation of reference numerals

1 birefringent layer 2 polarizer 3 protective film 11 polarizing plate 21 liquid crystal cell

Claims (24)

An optical film in which a transparent polymer film layer and a birefringent layer formed of a non-liquid crystalline polymer are laminated, wherein the birefringent layer satisfies the condition of the following formula (1) and the transparent polymer film An optical film in which the in-plane retardation of the layer is 50 nm or less.

nx ≧ ny> nz (1)

In the above formula (1), nx, ny and nz indicate the refractive indexes of the birefringent layer in the X-axis direction, the Y-axis direction and the Z-axis direction, respectively.
The X-axis direction is an axial direction indicating a maximum refractive index in the in-plane direction of the birefringent layer, the Y-axis direction is an axial direction perpendicular to the X-axis direction in the plane, The Z-axis direction indicates a thickness direction perpendicular to the X-axis direction and the Y-axis direction. The optical film according to claim 1, wherein the birefringence Δn (a) of the birefringent layer and the birefringence Δn (b) of the transparent polymer film layer satisfy the following expression (2).

Δn (a)> Δn (b) × 10 (2)
The optical film according to claim 1, wherein the birefringence (Δn) of the entire optical film is in a range of 0.0005 to 0.5. The non-liquid crystalline polymer forming the birefringent layer is at least one polymer selected from the group consisting of polyamide, polyimide, polyester, polyetherketone, polyamideimide and polyesterimide. Optical film.
The resin forming the transparent polymer film layer is an acetate resin, a polyester resin, a polyether sulfone resin, a polysulfone resin, a polycarbonate resin, a polyamide resin, a polyimide resin, a polyolefin resin, an acrylic resin, a polynorbornene resin, a cellulose resin, and a polyarylate. Resins, polystyrene resins, polyvinyl alcohol resins, polyvinyl chloride resins, polyvinylidene chloride resins, polyacrylic resins, mixed resins of these, liquid crystal polymers, and thermoplastic resins having a substituted imide group or unsubstituted imide group in the side chain The optical film according to any one of claims 1 to 4, wherein the optical film is at least one resin selected from the group consisting of a mixture of a thermoplastic resin having a substituted or unsubstituted phenyl group and a nitrile group in a chain. 5. The resin according to claim 1, wherein the resin forming the transparent polymer film layer is at least one of a mixed resin of an alternating copolymer of triacetyl acetate and isobutene and N-methylenemaleimide and an acrylonitrile / styrene copolymer. 6. The optical film according to any one of the above. The optical film according to any one of claims 1 to 6, wherein the transparent polymer film layer is manufactured by molding a resin material for forming the transparent polymer film layer into a film shape and performing a stretching treatment. 8. The optical film according to claim 1, wherein the transparent polymer film layer is used as a transparent protective film for a polarizing plate. 9. A polarizing plate comprising an optical film and a polarizer, wherein the optical film is the optical film according to claim 1. The polarizing plate according to claim 9, wherein the transparent polymer film layer of the optical film also functions as a transparent protective film of the polarizing plate. The polarizing plate according to claim 9, wherein the optical film functions as an optical compensation layer. A liquid crystal panel including a liquid crystal cell and an optical member, wherein the optical member is disposed on at least one surface of the liquid crystal cell, and the optical member is the optical film or the optical film according to claim 1. Item 12. A liquid crystal panel which is the polarizing plate according to any one of items 9 to 11. The liquid crystal cell includes a super twisted nematic (STN) cell, a twisted nematic (TN) cell, an in-plane switching (IPS) cell, a vertical aligned (VA) cell, an optically aligned birefringence (OCB) cell, and a hybrid aligned nematic (HAN). 13. The liquid crystal panel according to claim 12, which is at least one selected from the group consisting of cells and ASM (Axially Symmetric Alighned Microcell) cells. A liquid crystal display device comprising the liquid crystal panel according to claim 12. A self-luminous display device comprising at least one of the optical film according to any one of claims 1 to 8 and the polarizing plate according to any one of claims 9 to 11. An organic EL display comprising at least one of the optical film according to any one of claims 1 to 8 and the polarizing plate according to any one of claims 9 to 11. A method for producing an optical film in which a transparent polymer film layer and a birefringent layer are laminated, wherein a transparent polymer film having an in-plane retardation of 50 nm or less is prepared, and a non-liquid crystalline polymer solution is coated thereon. Then, a birefringent layer is formed by evaporating and removing the solvent in the solution, and the birefringent layer satisfies the condition of the following formula (1).

nx ≧ ny> nz (1)

In the above formula (1), nx, ny and nz indicate the refractive indexes of the birefringent layer in the X-axis direction, the Y-axis direction and the Z-axis direction, respectively.
The X-axis direction is an axial direction indicating a maximum refractive index in the in-plane direction of the birefringent layer, the Y-axis direction is an axial direction perpendicular to the X-axis direction in the plane, The Z-axis direction indicates a thickness direction perpendicular to the X-axis direction and the Y-axis direction. The two layers are formed so that the refractive index Δn (a) of the birefringent layer and the birefringent index Δn (b) of the transparent polymer film layer satisfy the condition of the following formula (2). Production method.

Δn (a)> Δn (b) × 10 (2)
The method according to claim 17, wherein the birefringence (Δn) of the entire optical film is in the range of 0.0005 to 0.5. 20. The non-liquid crystalline polymer forming the birefringent layer is at least one polymer selected from the group consisting of polyamide, polyimide, polyester, polyether ketone, polyamide imide and polyester imide. Manufacturing method. The resin forming the transparent polymer film layer is an acetate resin, a polyester resin, a polyether sulfone resin, a polysulfone resin, a polycarbonate resin, a polyamide resin, a polyimide resin, a polyolefin resin, an acrylic resin, a polynorbornene resin, a cellulose resin, and a polyarylate. Resins, polystyrene resins, polyvinyl alcohol resins, polyvinyl chloride resins, polyvinylidene chloride resins, polyacrylic resins, mixed resins of these, liquid crystal polymers, and thermoplastic resins having a substituted imide group or unsubstituted imide group in the side chain The method according to any one of claims 17 to 20, wherein the resin is at least one resin selected from the group consisting of a mixture of a thermoplastic resin having a substituted phenyl group or an unsubstituted phenyl group and a nitrile group in a chain. 21. The resin according to claim 17, wherein the resin forming the transparent polymer film layer is at least one of a mixed resin of an alternating copolymer of triacetyl acetate and isobutene and N-methylenemaleimide and an acrylonitrile / styrene copolymer. The production method according to any one of the above. The manufacturing method according to any one of claims 17 to 212, wherein the transparent polymer film layer is manufactured by forming a resin material for forming the transparent polymer film layer into a film shape and then performing a stretching treatment. 24. The production method according to claim 17, wherein after laminating the transparent polymer film layer and the birefringent layer, the laminate is stretched or shrunk.

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