JP3838522B2 - Manufacturing method of laminated retardation plate - Google Patents

Description

  The present invention relates to a method for manufacturing a laminated retardation plate.

  Conventionally, various image display devices require a retardation plate with a controlled refractive index in order to realize excellent display quality in all directions, and the type is, for example, a display method of a liquid crystal display device. It is selected according to etc. In particular, in a liquid crystal display device such as a VA (Vertically Aligned) type and an OCB (Optically Compensated Bend) type, the refractive index (nx, ny, nz) in three axial directions (X axis, Y axis, Z axis) is “nx”. > Ny> nz ”, that is, a retardation plate that exhibits optically negative biaxiality is required. Thus, as the retardation plate satisfying “nx> ny> nz”, for example, two stretched polymer films in which nx> ny = nz by uniaxial stretching at the free end are used, and the slow axis direction in the plane is There are known laminated retardation plates laminated so as to be orthogonal to each other, and single-layer retardation plates controlled to “nx> ny> nz” by transverse stretching or biaxial stretching of a polymer film.

  However, the former laminated phase difference plate has an advantage that the range of retardation values obtained by the combination of the stretched films is widened, but on the other hand, one sheet is thick and the film is further thickened by lamination. There were drawbacks. On the other hand, the latter single-layer retardation plate has the advantage of having an optical characteristic of “nx> ny> nz” even though it is a single layer, but on the other hand, it is thick and has a range of retardation values obtained. There is a disadvantage of being narrow. For this reason, it is necessary to further laminate another retardation film to widen the range of the retardation value. In addition, in order to obtain a retardation value whose thickness direction retardation value is significantly larger than the in-plane retardation value using this single-layer retardation plate, as in the case of the former laminated retardation plate, other levels It is necessary to laminate a phase difference film. As a result, the disadvantage of further thickening occurs.

  Also disclosed is a method of producing a single-layer retardation film that is thin and satisfies “nx> ny> nz” using a non-liquid crystal polymer such as polyimide (see, for example, Patent Document 1). ). However, for such a single-layer polyimide retardation film, if the thickness direction retardation is set large, the reason is unknown, but coloring is observed, and the display quality may be deteriorated.

JP 2000-190385 A

  Therefore, the present invention is a multilayered retardation plate that has excellent viewing angle characteristics and high contrast when used in a liquid crystal display device, and has a large thickness retardation value and can be thinned. An object of the present invention is to provide a method for producing a laminated retardation plate capable of preventing coloring.

In order to achieve the above object, the laminated retardation plate of the present invention comprises:
A laminated retardation plate comprising at least two optically anisotropic layers,
An optically anisotropic layer (A) made of a polymer and at least one non-liquid crystalline polymer selected from the group consisting of polyamide, polyimide, polyester, polyaryletherketone, polyetherketone, polyamideimide and polyesterimide. And (B)
The in-plane retardation (Re) represented by the following formula is 10 nm or more,
A method for producing a laminated retardation plate having a thickness direction retardation (Rth) represented by the following formula and a difference (Rth-Re) between the in-plane retardation (Re) of 50 nm or more,
On the polymer optical anisotropic layer (A), the non-liquid crystalline polymer solution is applied to form a coating film, and only the optical anisotropic layer (A) is dried while drying the coating film. The optically anisotropic layer (B) is formed by stretching the coating film and indirectly stretching the coating film .
Re = (nx−ny) · d
Rth = (nx−nz) · d
In the above equation, nx, ny, and nz represent the refractive indexes in the X-axis, Y-axis, and Z-axis directions of the laminated phase difference plate, respectively, and the X axis is the maximum in the plane of the laminated phase difference plate. An axial direction indicating a refractive index, the Y axis is an axial direction perpendicular to the X axis in the plane, and the Z axis is a thickness direction perpendicular to the X axis and the Y axis, and d Indicates the thickness of the laminated retardation plate.

  The inventors thus laminated the optically anisotropic layer (A) made of the polymer and the optically anisotropic layer (B) made of a non-liquid crystalline polymer such as the polyimide, whereby an in-plane retardation ( Re) is 10 nm or more, excellent optical properties such that the difference between the thickness direction retardation (Rth) and the in-plane retardation (Re) (Rth-Re) is 50 nm or more, and thinning is also realized. It was found that a laminated retardation plate was obtained. Furthermore, with such a laminated phase difference plate, it is possible to prevent coloring problems caused by realizing a large thickness direction retardation with a polyimide film alone as in the prior art. Therefore, according to the laminated retardation plate of the present invention, for example, when applied to various image display devices such as a liquid crystal display device, not only excellent display characteristics such as a wide viewing angle characteristic can be realized, but also the device itself. Since the thickness can be reduced, it is very useful.

  As described above, the laminated retardation plate of the present invention comprises at least a polymer optically anisotropic layer (A) and polyamide, polyimide, polyester, polyaryletherketone, polyetherketone, polyamideimide and polyesterimide. An optically anisotropic layer (B) made of at least one non-liquid crystalline polymer selected from the group, wherein the in-plane retardation (Re) is 10 nm or more, the thickness direction retardation (Rth) and the surface The difference (Rth−Re) from the internal phase difference (Re) is 50 nm or more.

  The laminated phase difference plate of the present invention has a refractive index of “nx> ny> nz” as a whole by laminating the optically anisotropic layers (A) and (B). In addition, since the Re value is 10 nm or more and the difference between Rth and Re (Rth-Re) is 50 nm or more, for example, display methods such as VA mode and OCB mode as described above In the liquid crystal display device, the birefringence of the liquid crystal cell can be sufficiently compensated, and an excellent viewing angle expansion effect can be obtained. When the Re value is less than 10 nm or the Rth-Re is less than 50 nm, there is a problem that the viewing angle expansion effect as described above cannot be obtained.

  The Re value is preferably in the range of 10 to 500 nm, more preferably in the range of 20 to 300 nm. The value of (Rth-Re) is preferably in the range of 50 to 1,000 nm, more preferably in the range of 50 to 900 nm, and particularly preferably in the range of 50 to 800 nm.

  The Rth is 60 nm or more, preferably in the range of 60 to 1500 nm, more preferably in the range of 60 to 1400 nm, and particularly preferably in the range of 60 to 1300 nm. Moreover, Rth / Re of the laminated phase difference plate of the present invention is 1 or more.

In the present invention, the optically anisotropic layer (A) is particularly limited if it can satisfy the conditions of Re and (Rth-Re) as a whole by combining with the optically anisotropic layer (B). However, for example, the in-plane retardation [Re (A)] shown in the following formula is 20 to 300 nm, the thickness direction retardation [Rth (A)] shown in the following formula and the in-plane retardation [Re (A) ]] [Rth (A) / Re (A)] is preferably 1.0 or more. This is because the ratio [Rth (A) / Re (A)] between the thickness direction retardation and the in-plane retardation is less than 1.0, for example, when used in a liquid crystal display device, in the thickness direction. This is because the phase difference value cannot be sufficiently compensated and the viewing angle becomes narrow, and when the in-plane phase difference is less than 20 nm or more than 300 nm, the viewing angle becomes narrow. The Rth (A) / Re (A) is more preferably 1.2 or more, and particularly preferably 1.2 to 40.
Re (A) = (nx (A) -ny (A)) · d (A)
Rth (A) = (nx (A) −nz (A)) · d (A)
In the above formula, nx (A), ny (A) and nz (A) represent the refractive indexes in the X-axis, Y-axis and Z-axis directions in the optical anisotropic layer (A), respectively. , The axial direction showing the maximum refractive index in the plane of the optical anisotropic layer (A), the Y axis is an axial direction perpendicular to the X axis in the plane, and the Z axis is In the thickness direction perpendicular to the X-axis and Y-axis, d (A) represents the thickness of the optically anisotropic layer (A) (the same applies hereinafter).

On the other hand, the refractive index of the optically anisotropic layer (B) is not particularly limited as long as it is an optically anisotropic layer made of a non-liquid crystal polymer as described above. For example, refraction in the X axis, Y axis, and Z axis is possible. The rate may satisfy the relationship of “nx (B)> ny (B)> nz (B)” or may satisfy “nx (B) ≈ny (B)> nz (B)”.
In the above formula, nx (B), ny (B), and nz (B) represent the refractive indexes in the X-axis, Y-axis, and Z-axis directions in the optical anisotropic layer (B), respectively, , The axial direction showing the maximum refractive index in the plane of the optical anisotropic layer (B), the Y axis is an axial direction perpendicular to the X axis in the plane, and the Z axis is The thickness direction perpendicular to the X axis and the Y axis is shown (the same applies hereinafter).

When the optically anisotropic layer (B) exhibits a relationship of “nx (B)> ny (B)> nz (B)”, the in-plane retardation [Re (B)] represented by the following formula is 3 nm or more, The ratio [Rth (B) / Re (B)] between the thickness direction retardation [Rth (B)] and the in-plane retardation [Re (B)] shown in the formula is preferably 1.0 or more. When the ratio [Rth (B) / Re (B)] of the thickness direction retardation to the in-plane retardation is less than 1.0, for example, when used in a liquid crystal display device, the retardation value in the thickness direction This is because there is a problem that the viewing angle cannot be sufficiently compensated and the viewing angle becomes narrow. Further, when the optical anisotropic layer (B) shows a relationship of “nx (B) ≈ny (B)> nz (B)”, that is, the in-plane retardation [Re (B)] is almost 0 nm. For example, by setting the in-plane retardation [Re (A)] of the optically anisotropic layer (A) within the above range, the conditions of Re and (Rth-Re) in the laminated retardation plate of the present invention are set as described above. It can also be satisfied. The Re (B) is more preferably 3 to 800 nm, particularly preferably 5 to 500 nm, and the Rth (B) / Re (B) is more preferably 1.2 or more, particularly preferably. 1.2 to 160. In the following formula, d (B) represents the thickness of the optically anisotropic layer (B) (the same applies hereinafter).
Re (B) = (nx (B) -ny (B)) · d (B)
Rth (B) = (nx (B) −nz (B)) · d (B)

  Specific examples of the combination of the optically anisotropic layer (A) and the optically anisotropic layer (B) include, for example, an in-plane retardation [Re (A)] of 20 to 300 nm, and a thickness direction retardation thereof. An optically anisotropic layer (A) having a ratio [Rth (A) / Re (A)] of [Rth (A)] to the in-plane retardation [Re (A)] of 1.0 or more; The retardation [Re (B)] is 3 nm or more, and the ratio [Rth (B) / Re (B)] between the thickness direction retardation [Rth (B)] and the in-plane retardation [Re (B)] is 1. And a combination with the optically anisotropic layer (B) which is not less than 0.0.

  The overall thickness of the laminated retardation plate of the present invention is usually 1 mm or less, and is sufficiently thinner than the conventional laminated retardation plate as described above. Preferably it is the range of 1-500 micrometers, Especially preferably, it is the range of 5-300 micrometers. For example, as described above, in comparison with “a conventional laminated phase difference plate in which two stretched polymer films with nx> ny = nz are laminated so that the in-plane slow axis directions are perpendicular to each other”, According to the laminated phase difference plate of the present invention, the thickness can be reduced to, for example, about one half.

  Moreover, the thickness of the said optically anisotropic layer (A) is 1-800 micrometers, for example, Preferably it is 5-500 micrometers, More preferably, it is 10-400 micrometers, Most preferably, it is 50-400 micrometers. The thickness of the optically anisotropic layer (B) is, for example, 1 to 50 μm, preferably 2 to 30 μm, and particularly preferably 1 to 20 μm. Thus, since the thickness of the optically anisotropic layer (B) can be sufficiently reduced, the overall thickness of the laminated retardation film of the present invention is also reduced, and the optical properties are improved by the lamination of the optically anisotropic layer (A). Will also be excellent.

  The material for forming the optically anisotropic layer (A) is not particularly limited, but for example, a polymer exhibiting positive birefringence is preferable. This is because by selecting such a polymer, the in-plane retardation and the thickness direction retardation of the optically anisotropic layer (A) can be increased. In the present invention, the “polymer exhibiting positive birefringence” refers to a polymer exhibiting the property that the refraction in the stretching direction is maximized when the film is stretched, but the optically anisotropic formed from the polymer. The layer (A) may be either a stretched film or an unstretched film (the same applies hereinafter).

  As the polymer, a stretched film can be used as the form of the optically anisotropic layer (A) as described above, and therefore, for example, a thermoplastic polymer that is easily stretched is preferable. Examples of the thermoplastic polymer include polyolefin (polyethylene, polypropylene, etc.), polynorbornene-based polymer, polyester, polyvinyl chloride, polyacrylonitrile, polysulfone, polyarylate, polyvinyl alcohol, polymethacrylic ester, polyacrylic ester, and cellulose. Esters and copolymers thereof can be used. These polymers may be used alone or in combination of two or more. Moreover, the polymer film described in JP 2001-343529 A (WO01 / 37007) can also be used as the optically anisotropic layer (A). Examples of the polymer material include a resin composition containing a thermoplastic resin having a substituted or unsubstituted imide group in the side chain and a thermoplastic resin having a substituted or unsubstituted phenyl group and cyano group in the side chain. Examples thereof include a resin composition having an alternating copolymer composed of isobutene and N-methylenemaleimide and an acrylonitrile / styrene copolymer. The polymer film may be, for example, an extruded product of the resin composition. Moreover, it is preferable that it is excellent in transparency.

  The optical anisotropic layer (B) is formed of a non-liquid crystal material such as polyamide, polyimide, polyester, polyaryletherketone, polyetherketone, polyamideimide, and polyesterimide that is excellent in heat resistance, chemical resistance, transparency, and the like. Polymer. Such a non-liquid crystalline material, for example, unlike a liquid crystalline material, forms a film exhibiting optical uniaxiality such as nx> nz and ny> nz depending on its own property, regardless of the orientation of the substrate. For this reason, for example, the substrate used when forming the anisotropic layer (B) is not limited to an oriented substrate, and for example, an unoriented substrate can be used as it is.

  Any one of these polymers may be used alone, or a mixture of two or more having different functional groups such as a mixture of polyaryletherketone and polyamide may be used. . Among such polymers, polyimide is particularly preferable because of its 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. The weight average molecular weight can be measured, for example, by gel permeation chromatography (GPC) using polyethylene oxide as a standard sample and DMF (N, N-dimethylformamide) as a solvent.

  As the polyimide, for example, a polyimide that has high in-plane orientation and is 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 2000-511296 A, and has the following formula ( A polymer containing one or more repeating units shown in 1) can be used.

前記式（１）中、Ｒ^３〜Ｒ^６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Ｃ_１〜_１０アルキル基で置換されたフェニル基、およびＣ_１〜_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、Ｒ^３〜Ｒ^６は、ハロゲン、フェニル基、１〜４個のハロゲン原子またはＣ_１〜_１０アルキル基で置換されたフェニル基、およびＣ_１〜_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 are each selected from hydrogen, halogen, a phenyl group, a phenyl group substituted with ₁ to 4 halogen atoms or a C ₁ to ₁₀ alkyl group, and a C ₁ to ₁₀ alkyl group. And at least one substituent selected independently from the group. ^Preferably, R 3 to R ⁶ is a halogen, a phenyl group, each independently from the group consisting of one to four halogen atoms or _C 1 _{~ 10} alkyl-substituted phenyl, and _C 1 _{~ 10} alkyl group It is at least one type of substituent selected.

In the formula (1), Z represents a tetravalent aromatic group C ₆ ~ _20, preferably a pyromellitic group, a polycyclic aromatic group, a derivative of a polycyclic aromatic group, or, It is group represented by following formula (2).

前記式（２）中、Ｚ’は、例えば、共有結合、Ｃ（Ｒ^７）_２基、ＣＯ基、Ｏ原子、Ｓ原子、ＳＯ_２基、Ｓｉ（Ｃ_２Ｈ_５）_２基、または、ＮＲ^８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。Ｒ^７は、それぞれ独立に、水素またはＣ（Ｒ^９）_３である。Ｒ^８は、水素、炭素原子数１〜約２０のアルキル基、またはＣ_６〜_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。Ｒ^９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, C (R ⁷ ) ₂ group, CO group, O atom, S atom, SO ₂ group, Si (C ₂ H ₅ ) ₂ group, or NR ^Eight groups, and when there are a plurality of groups, they are the same or different. W represents an integer from 1 to 10. Each R ⁷ is independently hydrogen or C (R ⁹ ) ₃ . R ⁸ is hydrogen, an alkyl group or a _C 6 _{~ 20} aryl group, the carbon atom number from 1 to about 20, for a plurality, they may be the same or different. Each R ⁹ is independently hydrogen, fluorine, or chlorine.

Examples of the polycyclic aromatic group include a tetravalent group derived from naphthalene, fluorene, benzofluorene or anthracene. The substitution Examples of the substituted derivatives of polycyclic aromatic group, for example, an alkyl group of C ₁ ~ _10, at least one group selected from the group consisting of fluorinated derivatives, and F or a halogen such as Cl And the above-mentioned polycyclic aromatic group.

  In addition, for example, a homopolymer described in JP-A-8-511812, wherein the repeating unit is represented by the following general formula (3) or (4), or the repeating unit is represented by the following general formula (5): The polyimide etc. which are shown are mention | raise | lifted. In addition, the polyimide of following formula (5) is a preferable form of the homopolymer of following formula (3).

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, or a C (CX ₃ ) ₂ group. (Where X is halogen), from the group consisting of CO, O, S, SO ₂ , Si (CH ₂ CH ₃ ) ₂ and N (CH ₃ ) groups, respectively It represents independently selected groups, and may be the same or different.

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 C _1-3 alkyl group, a C _1-3 halogenated alkyl group, a phenyl group, or a substituted phenyl group, and in a plurality of cases, they are the same or different. Examples of the substituted phenyl group include substituted phenyl groups having at least one substituent selected from the group consisting of halogen, C _1-3 alkyl groups, and C _1-3 halogenated alkyl groups. 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.

  In the formulas (3) to (5), Q is a substituent, and f represents the number of substitutions. Q is, for example, selected from the group consisting of hydrogen, halogen, alkyl group, substituted alkyl group, nitro group, cyano group, thioalkyl group, alkoxy group, aryl group, substituted aryl group, alkyl ester group, and substituted alkyl ester group And when Q is plural, they are 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 these, R ¹⁰ and R ¹¹ are preferably each independently a halogenated alkyl group.

In the formula (5), M ¹ and M ² are the same or different and are, for example, a halogen, a C _1-3 alkyl group, a C _1-3 halogenated alkyl group, a phenyl group, or a substituted phenyl group. is there. Examples of the halogen include fluorine, chlorine, bromine and iodine. Examples of the substituted phenyl group include substituted phenyl groups having at least one type of substituent selected from the group consisting of halogen, C _1-3 alkyl groups, and C _1-3 halogenated alkyl groups. .

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

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

  Examples of the acid dianhydride include aromatic tetracarboxylic dianhydrides. Examples of the aromatic tetracarboxylic dianhydride include pyromellitic dianhydride, benzophenone tetracarboxylic dianhydride, naphthalene tetracarboxylic dianhydride, heterocyclic aromatic tetracarboxylic dianhydride, 2, And 2'-substituted biphenyltetracarboxylic dianhydride.

  Examples of the pyromellitic dianhydride include pyromellitic dianhydride, 3,6-diphenylpyromellitic dianhydride, 3,6-bis (trifluoromethyl) pyromellitic dianhydride, and 3,6-dibromo. Examples include pyromellitic dianhydride and 3,6-dichloropyromellitic dianhydride. Examples of the benzophenone tetracarboxylic dianhydride include 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 2,3,3 ′, 4′-benzophenone tetracarboxylic dianhydride, 2 , 2 ′, 3,3′-benzophenone tetracarboxylic dianhydride and the like. Examples of the naphthalenetetracarboxylic dianhydride include 2,3,6,7-naphthalene-tetracarboxylic dianhydride, 1,2,5,6-naphthalene-tetracarboxylic dianhydride, 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. Pyridine-2,3,5,6-tetracarboxylic dianhydride and the like. 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, etc. 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) -1,1,1,3,3 3-hexafluoropropane dianhydride, 4,4 ′-(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'-I Propylidene-di (p-phenyleneoxy)] bis (phthalic anhydride), N, N- (3,4-dicarboxyphenyl) -N-methylamine dianhydride, bis (3,4-dicarboxyphenyl) And diethylsilane dianhydride.

  Among these, the aromatic tetracarboxylic dianhydride is preferably 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 benzene diamine, diaminobenzophenone, naphthalene diamine, 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, Examples include 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.

  In addition to these, as the aromatic diamine, 4,4′-diaminobiphenyl, 4,4′-diaminodiphenylmethane, 4,4 ′-(9-fluorenylidene) -dianiline, 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-aminophen Xyl) benzene, 1,3-bis (4-aminophenoxy) 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] -1,1,1,3 , 3,3-hexafluoropropane, 4,4′-diaminodiphenylthioether, 4,4′-diaminodiphenylsulfone, and the like.

  Examples of the polyether ketone which is a material for forming the birefringent layer (a) include polyaryl ether ketones represented by the following general formula (7) described in JP-A No. 2001-49110. .

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 substitutions. X is, for example, a halogen atom, a lower alkyl group, a halogenated alkyl group, a lower alkoxy group, or a halogenated alkoxy group, and when there are a plurality of Xs, 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. Examples of the lower alkyl group, for example, preferably a lower alkyl group having a straight-chain or branched C ₁ ~ _6, more preferably a straight-chain or branched alkyl group of C ₁ ~ _4. 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 halides of the lower alkyl group such as a trifluoromethyl group. Examples of the lower alkoxy group, for example, preferably a straight chain or branched chain alkoxy group of C ₁ ~ _6, more preferably a straight chain or branched chain alkoxy group of C ₁ ~ _4. 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 halides of the lower alkoxy group such as a trifluoromethoxy group.

  In the 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 are present in the para position.

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

In the above formula (8), ^{R 2} 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 divalent groups derived from biphenylsulfone. In these divalent aromatic groups, hydrogen directly bonded to the aromatic group may be substituted with a halogen atom, a lower alkyl group or a lower alkoxy group. Among these, as R ² , an aromatic group selected from the group consisting of the following formulas (9) to (15) is preferable.

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 the formula (8).

  Furthermore, in said Formula (7), n represents a polymerization degree, for example, is the range of 2-5000, Preferably, it is the range of 5-500. Further, 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 mode of the repeating unit may be block polymerization or random polymerization.

  Furthermore, the end of the polyaryl ether ketone represented by the formula (7) is preferably fluorine on the p-tetrafluorobenzoylene group side and a hydrogen atom on the oxyalkylene group side. 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 formula (7).

  Specific examples of the polyaryletherketone represented by the formula (7) include those represented by the following formulas (18) to (21). In each formula below, n represents the formula (7). Represents the same degree of polymerization.

  In addition to these, examples of the polyamide or polyester that is a material for forming the birefringent layer (a) include polyamides and polyesters described in JP-T-10-508048. The unit can be represented by the following general formula (22), for example.

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、Ｃ_２アルキレン基、ハロゲン化Ｃ_２アルキレン基、ＣＨ_２基、Ｃ（ＣＸ_３）_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、ＳＯ_２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、Ｃ_１−３アルキル基およびＣ_１−３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 formula (22), Y is O or NH. E is, for example, a covalent bond, a C ₂ alkylene group, a halogenated C ₂ alkylene group, a CH ₂ group, a C (CX ₃ ) ₂ group (where X is a halogen or hydrogen), a CO group, It is at least one kind of group selected from the group consisting of O atom, S atom, SO ₂ group, Si (R) ₂ group, and N (R) group, and may be the same or different. In E, R is at least one of a C _1-3 alkyl group and a C _1-3 halogenated alkyl group, and is in a meta position or a para position with respect to a carbonyl functional group or a Y group.

  Moreover, in said (22), A and A 'are substituents, and t and z represent the number of each substitution. 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, an alkoxy group represented by hydrogen, halogen, C _1-3 alkyl group, C _1-3 halogenated alkyl group, OR (where R is as defined above), aryl Group, substituted aryl group by halogenation, C _1-9 alkoxycarbonyl group, C _1-9 alkylcarbonyloxy group, C _1-12 aryloxycarbonyl group, C _1-12 arylcarbonyloxy group and substituted derivatives thereof, C It is selected from the group consisting of a _1-12 arylcarbamoyl group and a C _1-12 arylcarbonylamino group and substituted derivatives thereof, and in the plurality of cases, they are the same or different. The A ′ is, for example, selected from the group consisting of halogen, a C _1-3 alkyl group, a C _1-3 halogenated alkyl group, a phenyl group, and a substituted phenyl group, and in a plurality of cases, they are the same or different. Examples of the substituent on the phenyl ring of the substituted phenyl group include halogen, a C _1-3 alkyl group, a C _1-3 halogenated alkyl group, and combinations thereof. The t is an integer from 0 to 4, and the z is an integer from 0 to 3.

  Among the repeating units of polyamide or polyester represented by the 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 those defined in the formula (22), and v is an integer of 0 to 3, preferably 0 to 2. x and y are each 0 or 1, but are not 0 at the same time.

  Next, the laminated phase difference plate of the present invention can be manufactured as follows, for example.

  First, the optical anisotropic layer (A) is prepared. As described above, the optical anisotropic layer (A) has an in-plane retardation [Re (A)] of 20 to 300 nm, and a thickness direction retardation [Rth (A)] and the in-plane retardation [Re The ratio [Rth (A) / Re (A)] to (A)] may be 1.0 or more. As described above, the polymer film may be an unstretched film or a stretched film. The stretched film can be obtained, for example, by stretching a polymer film formed by extrusion molding or casting film formation. The stretched film may be a uniaxially stretched film or a biaxially stretched film.

  The stretching method is not particularly limited, and examples thereof include conventionally known stretching methods such as uniaxial stretching such as roll method longitudinal stretching and biaxial stretching such as tenter transverse stretching. The roll method longitudinal stretching may be, for example, either a method using a heated roll, a method using an atmosphere under heating conditions, or a combination thereof. Examples of the biaxial stretching include simultaneous biaxial stretching by an all tenter method and sequential biaxial stretching by a roll tenter method. In addition, the draw ratio is not particularly limited, and can be determined as appropriate depending on, for example, the drawing method and the forming material. As the characteristics of the optically anisotropic layer (A), those excellent in surface smoothness, uniformity of birefringence, transparency and heat resistance are preferable.

  The thickness of the polymer film before stretching is usually 10 to 800 μm, preferably 10 to 700 μm. And the thickness of the polymer film after extending | stretching, ie, an optically anisotropic layer (A), is as above-mentioned.

  On the other hand, the optically anisotropic layer (B) has an in-plane retardation [Re (B)] of 3 nm or more, and a ratio [Rth (B) / Re (B) between the thickness direction retardation and the in-plane retardation. )] Is not particularly limited as long as it is 1.0 or more, but for example, it can be prepared as follows.

  The optically anisotropic layer (B) is formed, for example, by coating the non-liquid crystalline polymer on a substrate to form a coating film, and solidifying the non-liquid crystalline polymer in the coating film, It can be formed on a substrate. The non-liquid crystal polymer such as polyimide exhibits optical characteristics of nx> nz and ny> nz (nx≈ny> nz) regardless of the orientation of the substrate. For this reason, an optically anisotropic layer, that is, an optically anisotropic layer showing a phase difference only in the thickness direction can be formed. In addition, the said optically anisotropic layer (B) may peel and use from the said base material, and may be used in the state formed on the base material.

  At this time, it is preferable to use the optically anisotropic layer (A) as the substrate. If the optically anisotropic layer (A) is used as a base material and the non-liquid crystalline polymer is directly coated thereon, the optically anisotropic layers (A) and (B) are laminated with an adhesive or an adhesive. This is because the number of stacked layers is reduced and the thickness can be further reduced.

  Further, as described above, since the non-liquid crystal polymer has a property of exhibiting optical uniaxiality, it is not necessary to use the orientation of the substrate. For this reason, both the oriented substrate and the non-oriented substrate can be used as the base material. Further, for example, a phase difference due to birefringence may be generated, or a phase difference due to birefringence may not be generated. Examples of the transparent substrate that generates a phase difference due to birefringence include a stretched film and the like, and those having a controlled refractive index in the thickness direction can also be used. The refractive index can be controlled by, for example, a method in which a polymer film is bonded to a heat-shrinkable film and then heated and stretched.

  The method for coating the non-liquid crystalline polymer on the substrate is not particularly limited. For example, the non-liquid crystalline polymer is heated and melted as described above, or the non-liquid crystalline polymer is applied. Examples thereof include a method of applying a polymer solution dissolved in a solvent. Among them, the method of applying the polymer solution is preferable because of excellent workability.

  The polymer concentration in the polymer solution is not particularly limited. For example, since the viscosity is easy to apply, for example, the non-liquid crystalline polymer may be 5 to 50 parts by weight with respect to 100 parts by weight of the solvent. The amount is preferably 10 to 40 parts by weight.

  The solvent of the polymer solution is not particularly limited as long as the forming material such as the non-liquid crystalline polymer can be dissolved, and can be appropriately determined according to the type of the forming material. Specific examples include, for example, halogenated hydrocarbons such as chloroform, dichloromethane, carbon tetrachloride, dichloroethane, tetrachloroethane, trichloroethylene, tetrachloroethylene, chlorobenzene, and orthodichlorobenzene; phenols such as phenol and parachlorophenol; benzene, toluene, Aromatic hydrocarbons such as xylene, methoxybenzene, 1,2-dimethoxybenzene; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, cyclopentanone, 2-pyrrolidone, N-methyl-2-pyrrolidone; Ester solvents such as ethyl acetate and butyl acetate; t-butyl alcohol, glycerin, ethylene glycol, triethylene glycol, ethylene glycol monomethyl ether, die Alcohol solvents such as lenglycol dimethyl ether, propylene glycol, dipropylene glycol and 2-methyl-2,4-pentanediol; amide solvents such as dimethylformamide and dimethylacetamide; nitrile solvents such as acetonitrile and butyronitrile; Examples include ether solvents such as diethyl ether, dibutyl ether and tetrahydrofuran; carbon disulfide, ethyl cellosolve, butyl cellosolve and the like. One type of these solvents may be used, or two or more types may be used in combination.

  For example, the polymer solution may further contain various additives such as a stabilizer, a plasticizer, and metals as required.

  Further, the polymer solution may contain other different resins as long as the orientation of the forming material is not significantly lowered. Examples of the other resin include various general-purpose resins, engineering plastics, thermoplastic resins, and thermosetting resins.

  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), polyethersulfone (PES), polyketone (PK), polyimide (PI), polycyclohexanedimethanol terephthalate (PCT), polyarylate (PAR), and liquid crystal polymer. (LCP) and the like. Examples of the thermosetting resin include an epoxy resin and a phenol novolac resin.

  Thus, when mix | blending said other resin etc. in the said polymer solution, the compounding quantity is 0-50 mass% with respect to the said polymer material, for example, Preferably, 0-30 mass% It is.

  Examples of the coating method for the polymer solution include spin coating, roll coating, flow coating, printing, dip coating, casting film formation, bar coating, and gravure printing. Moreover, in the case of coating, the superposition | polymerization method of a polymer layer is also employable as needed.

  Solidification of the non-liquid crystalline polymer forming the coating film can be performed, for example, by drying the coating film. The drying method is not particularly limited, and examples thereof include natural drying and heat drying. The conditions can also be appropriately determined according to, for example, the type of the non-liquid crystalline polymer, the type of the solvent, etc. For example, the temperature is usually 40 ° C. to 300 ° C., preferably 50 ° C. to 250 ° C. More preferably, it is 60 degreeC-200 degreeC. The coating film may be dried at a constant temperature or may be performed while increasing or decreasing the temperature stepwise. The drying time is not particularly limited, but is usually 10 seconds to 30 minutes, preferably 30 seconds to 25 minutes, and more preferably 1 minute to 20 minutes or less.

  The solvent of the polymer solution remaining in the optically anisotropic layer (B) may change the optical characteristics of the laminated retardation plate over time in proportion to the amount of the solvent. For example, 5% or less is preferable, more preferably 2% or less, and still more preferably 0.2% or less.

  On the other hand, by forming a coating film on a substrate in the same manner as described above and stretching the transparent substrate and the coating film together, optical biaxiality, that is, optical anisotropy exhibiting nx> ny> nz A layer (B) can also be formed on a base material. According to this method, the laminate of the base material and the coating film is stretched together in one direction in the plane, whereby the coating film further generates a refractive difference in the plane, and optical two-dimensional It shows axiality (nx> ny> nz).

  The method for stretching the laminate of the base material and the coating film is not particularly limited. For example, free end longitudinal stretching for uniaxial stretching in the longitudinal direction, uniaxial stretching in the width direction with the longitudinal direction of the film fixed. Examples include fixed end transverse stretching, and sequential or simultaneous biaxial stretching in which stretching is performed in both the longitudinal direction and the width direction.

And the extending | stretching of the said laminated body extends | stretches only the said base material from the following reasons. When only the base material is stretched, the coating film on the base material is stretched indirectly by the tension generated in the base material by this stretching. And, since stretching the single layer body is usually uniform stretching rather than stretching the laminate, if only the transparent substrate is uniformly stretched as described above, the base material is accompanied accordingly. This is because the upper coating film can also be stretched uniformly.

  The stretching conditions are not particularly limited, and can be appropriately determined according to, for example, the type of the base material and the non-liquid crystalline polymer. Moreover, the heating temperature at the time of stretching can be appropriately determined according to, for example, the type of the base material or non-liquid crystalline polymer, the glass transition point (Tg) thereof, the type of additive, and the like. Preferably, it is 120-220 degreeC, Most preferably, it is 140-200 degreeC. In particular, the temperature is preferably near Tg of the base material or higher.

  The laminated phase difference plate of the present invention is formed by laminating the optically anisotropic layer (A) and the optically anisotropic layer (B) obtained as described above through, for example, an adhesive or an adhesive. be able to. In addition, the optical anisotropic layer (B) formed on the base material (first base material) is bonded to the optical anisotropic layer (A) via an adhesive or the like, and then the first base The material may be peeled off.

  The adhesive or pressure-sensitive adhesive is not particularly limited, and has been publicly known, for example, a transparent pressure-sensitive adhesive or pressure-sensitive adhesive such as acrylic, silicone, polyester, polyurethane, polyether, and rubber. Things can be used. Among these, those that do not require a high-temperature process during curing and drying are preferable from the viewpoint of preventing changes in the optical properties of the laminated phase difference body. Specifically, a long curing process and drying time are required. Acrylic adhesive that does not work is desirable.

  In addition, the bonding method is not limited to this. For example, as described above, the optical anisotropic layer (A) is used as a base material for forming the optical anisotropic layer (B), and the optical layer is directly formed thereon. By forming the anisotropic layer (B), the both may be directly laminated to form the laminated retardation plate of the present invention. This is because, in such a form, for example, the pressure-sensitive adhesive layer and the adhesive layer are not necessary, so that the number of stacked layers can be reduced, and further reduction in thickness can be realized. Alternatively, the optically anisotropic layer (B) may be directly laminated as described above using the optically anisotropic layer (A) as a base material, and this laminate may be further stretched as described above.

  The laminated retardation plate of the present invention preferably further has a pressure-sensitive adhesive layer or an adhesive layer as the outermost layer. This facilitates adhesion between the laminated retardation plate of the present invention and other members such as other optical layers and liquid crystal cells, and can prevent the laminated retardation plate of the present invention from peeling off. . In addition, the said adhesive may be one outermost layer of a laminated phase difference plate, and may be laminated | stacked on both outermost layers.

  The material of the adhesive layer is not particularly limited, and a conventionally known material such as an acrylic polymer can be used. In particular, foaming and peeling due to moisture absorption, deterioration of optical characteristics due to thermal expansion difference, etc. From the viewpoints of preventing warpage of the liquid crystal cell when used, and hence the formability of a liquid crystal display device having high quality and excellent durability, for example, it is preferable that the adhesive layer has a low moisture absorption and excellent heat resistance. Moreover, the adhesion layer etc. which contain microparticles | fine-particles and show light diffusibility may be sufficient. The pressure-sensitive adhesive layer is formed on the surface of the laminated phase difference plate by, for example, directly adding a solution or melt of various pressure-sensitive adhesive materials to a predetermined surface of the polarizing plate by a developing method such as casting or coating. The layer can be formed by a method of forming a pressure-sensitive adhesive layer on a liner, which will be described later, and transferred to a predetermined surface of the laminated retardation plate.

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

  For example, the pressure-sensitive adhesive layer may be a single layer or a laminate. As the laminate, for example, a laminate in which different compositions and different types of single layers are combined can be used. Moreover, when arrange | positioning on both surfaces of the said laminated phase difference plate, the same adhesive layer may be sufficient, respectively, for example, and a different composition and a different kind of adhesive layer may be sufficient.

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.

  As the pressure-sensitive adhesive that forms the pressure-sensitive adhesive layer, for example, one that is excellent in optical transparency and exhibits appropriate wettability, cohesiveness, and adhesive pressure-sensitive adhesive properties 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 property of the pressure-sensitive adhesive layer is, for example, the degree of cross-linking depending on the composition and molecular weight of the base polymer forming the pressure-sensitive adhesive layer, the crosslinking method, the content ratio of the crosslinkable functional group, the blending ratio of the crosslinking agent, and the like. It can be suitably carried out by a conventionally known method such as adjusting the molecular weight.

  As described above, the laminated retardation plate of the present invention may be used alone, or may be used in various optical applications as a laminated body in combination with other optical members as necessary. Specifically, it is useful as an optical compensation member. Although it does not restrict | limit especially as said other optical member, For example, the polarizer etc. which are shown below are mention | raise | lifted.

  The laminated phase difference plate of the present invention can be used as the optical film in a laminated polarizing plate including an optical film and a polarizer, for example.

  The configuration of such a polarizing plate is not particularly limited as long as it has the laminated retardation plate of the present invention, and examples thereof include the following. The laminated polarizing plate is not limited to the following configuration as long as it has the laminated retardation plate of the present invention and a polarizer, and may further contain other optical members and the like. Other structural requirements may be omitted.

  As an example of the laminated polarizing plate, for example, it has the laminated retardation plate of the present invention, a polarizer and two transparent protective layers, and a transparent protective layer is provided on both sides of the polarizer via an adhesive layer. Each layer is laminated, and the laminated phase difference plate is further laminated on one transparent protective layer via an adhesive layer. The laminated retardation plate is a laminated body of the optically anisotropic layer (A) and the optically anisotropic layer (B) as described above, but any surface may face the transparent protective layer.

  Note that the transparent protective layer may be laminated on both sides of the polarizer as described above, or may be laminated only on one of the surfaces. Moreover, when laminating | stacking on both surfaces, the same kind of transparent protective layer may be used, for example, or a different kind of transparent protective layer may be used. Moreover, the adhesion method of each layer is not particularly limited, and a pressure-sensitive adhesive or an adhesive may be used as the adhesive layer. When direct lamination is possible, the adhesive layer may not be interposed.

  In addition, as another example of the laminated polarizing plate, the laminated retardation plate of the present invention, a polarizer and a transparent protective layer, the transparent protective layer is laminated on one surface of the polarizer via an adhesive layer, The laminated retardation plate is laminated on the other surface of the polarizer via an adhesive layer.

  And since a laminated phase difference plate is a laminated body which laminated | stacked the optical anisotropic layer (A) and the optical anisotropic layer (B) through the contact bonding layer, any surface may face a polarizer. However, for the following reasons, for example, it is preferable that the optically anisotropic layer (A) side of the laminated retardation plate is disposed so as to face the polarizer. This is because the optically anisotropic layer (A) of the laminated retardation plate can also be used as a transparent protective layer in the laminated polarizing plate with such a configuration. That is, instead of laminating transparent protective layers on both sides of the polarizer, a transparent protective layer is laminated on one surface of the polarizer, and the optically anisotropic layer (A) faces the other surface. By laminating the laminated retardation plate, the optical anisotropic layer (A) also serves as the other transparent protective layer of the polarizer. For this reason, the polarizing plate made still thinner can be obtained.

  The polarizer is not particularly limited, and for example, by dying dichroic substances such as iodine and dichroic dyes on various films by using a conventionally known method, dyeing, crosslinking, stretching, and drying. The prepared one can be used. Among these, a film that transmits linearly polarized light when natural light is incident is preferable, and a film that is excellent in light transmittance and degree of polarization is preferable. Examples of the various films that adsorb the dichroic substance include high hydrophilicity such as polyvinyl alcohol (PVA) film, partially formalized PVA film, ethylene / vinyl acetate copolymer partially saponified film, and cellulose film. In addition to these, for example, polyene oriented films such as PVA dehydrated products and polyvinyl chloride dehydrochlorinated products can be used. Among these, PVA film is preferable. Moreover, although the thickness of the said polarizing film is the range of 1-80 micrometers normally, it is not limited to this.

  The protective layer is not particularly limited, and a conventionally known transparent film can be used. For example, a layer excellent in transparency, mechanical strength, thermal stability, moisture barrier property, isotropy, and the like is preferable. Specific examples of the material for such a transparent protective layer include cellulose resins such as triacetyl cellulose, polyester, polycarbonate, polyamide, polyimide, polyethersulfone, polysulfone, polystyrene, and polynorbornene. Transparent resins such as polyethylene, polyolefin, acrylic, and acetate. Further, examples thereof include thermosetting resins such as acrylic, urethane, acrylic urethane, epoxy, and silicone, or ultraviolet curable resins. Among these, a TAC film whose surface is saponified with alkali or the like is preferable from the viewpoint of polarization characteristics and durability.

Moreover, the polymer film as described in Unexamined-Japanese-Patent No. 2001-343529 (WO01 / 37007) is mention | raise | lifted. Examples of the polymer material include a resin composition containing a thermoplastic resin having a substituted or unsubstituted imide group in the side chain and a thermoplastic resin having a substituted or unsubstituted phenyl group and a nitrile group in the side chain. For example, a resin composition having an alternating copolymer composed 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.

Moreover, it is preferable that the said protective layer does not have 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. It is in the range of ~ + 45 nm. When the retardation value is in the range of −90 nm to +75 nm, the coloring (optical coloring) of the polarizing plate due to 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

The transparent protective layer may further have an optical compensation function. As described above, the transparent protective layer having an optical compensation function is intended to prevent coloring or increase the viewing angle for good viewing caused by a change in viewing angle based on a phase difference in a liquid crystal cell, for example. A well-known thing can be used. Specifically, for example, various stretched films obtained by uniaxially or biaxially stretching the above-described transparent resin, alignment films such as liquid crystal polymers, and laminates in which alignment layers such as liquid crystal polymers are arranged on a transparent substrate. It is done. Among these, since it is possible to achieve a wide viewing angle with good visibility, the alignment film of the liquid crystal polymer is preferable, and in particular, the optical compensation layer composed of the inclined alignment layer of the discotic or nematic liquid crystal polymer is used as described above. 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 triacetyl cellulose film.

The thickness of the transparent protective layer is not particularly limited, and can be appropriately determined depending on, for example, the phase difference and the protective strength, but is usually 500 μm or less, preferably 5 to 300 μl, more preferably 5 to 150 μm. Is

  The transparent protective layer is appropriately formed 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, the optical compensation retardation plate, or the like on the polarizing film. It is also possible to use a commercial product.

  The transparent protective layer may be further subjected to, for example, a hard coat treatment, an antireflection treatment, a treatment for preventing sticking or diffusion, antiglare, and the like. The hard coat treatment is for the purpose of preventing scratches on the surface of the polarizing plate, for example, a treatment for forming a cured film having excellent hardness and slipperiness composed of a curable resin on the surface of the transparent protective layer. It is. As the curable resin, for example, a silicone-based, urethane-based, acrylic-based, or epoxy-based ultraviolet curable 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 intended to prevent 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 intended to prevent visual interference of the light transmitted through the polarizing plate due to reflection of external light on the surface of the polarizing plate, for example, on the surface of the transparent protective layer by a conventionally known method, This can be done by forming a fine uneven structure. Examples of a method for forming such a concavo-convex structure include a roughening method by sandblasting or embossing, a method of forming the transparent protective layer by blending transparent fine particles in the transparent resin as described above, and the like. It is done.

  Examples of the transparent fine particles include silica, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, antimony oxide, and the like. In addition, conductive inorganic fine particles, crosslinked or uncrosslinked Organic fine particles composed of polymer particles and 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 blending ratio of the transparent fine particles is not particularly limited, but is generally preferably in the range of 2 to 70 parts by mass and 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 antiglare layer containing the transparent fine particles can be used as, for example, the transparent protective layer itself, or may be formed as a coating layer on the surface of the transparent protective layer. Furthermore, the anti-glare layer may also serve as a diffusion layer (visual compensation function or the like) for diffusing the light transmitted through the polarizing plate to expand the viewing angle.

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

  The method of laminating each component (optically anisotropic layer (A), optically anisotropic layer (B), laminated phase difference plate, polarizer, transparent protective layer, etc.) is not particularly limited, and is performed by a conventionally known method. be able to. 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 component. Examples of the adhesive include polymer adhesives such as acrylic, vinyl alcohol, silicone, polyester, polyurethane, and polyether, and rubber adhesives. The pressure-sensitive adhesives and adhesives as described above are hardly peeled off due to, for example, the influence of humidity and heat, and are excellent in light transmittance and degree of polarization. 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 adhesion treatment. These adhesives and pressure-sensitive adhesives may be applied to the surface of the polarizer or the transparent protective layer as they are, for example, or a layer such as a tape or sheet composed of the adhesive or pressure-sensitive adhesive is disposed on the surface. May be. For example, when prepared as an aqueous solution, other additives and catalysts such as acids may be blended as necessary. In addition, when apply | coating the said adhesive agent, you may mix | blend another additive and catalysts, such as an acid, with the said adhesive agent aqueous solution, for example. 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. The method is not particularly limited, and for example, a conventionally known method using an adhesive such as an acrylic polymer or a vinyl alcohol polymer can be employed. In addition, an adhesive containing a water-soluble cross-linking agent of PVA polymer such as glutaraldehyde, melamine, oxalic acid and the like can be obtained because it can form a polarizing plate that is difficult to peel off due to humidity, heat, etc. and has excellent light transmittance and polarization degree. preferable. These adhesives can be used by, for example, applying the aqueous solution to the surface of each component and drying. In the aqueous solution, for example, other additives and a catalyst such as an acid can be blended as necessary. Among these, as the adhesive, a PVA adhesive is preferable from the viewpoint of excellent adhesiveness with a PVA film.

  In addition to the polarizer as described above, the laminated retardation plate of the present invention is used in combination with conventionally known optical members such as various other retardation plates, diffusion control films, brightness enhancement films, and the like. You can also Examples of the retardation plate include a uniaxially or biaxially stretched polymer film, a Z-axis aligned treatment, a liquid crystalline polymer coating film, and the like. Examples of the diffusion control film include films utilizing diffusion, scattering, and refraction, and these can be used for, for example, control of viewing angle, glare related to resolution, and control of scattered light. As the brightness enhancement film, for example, a brightness enhancement film using selective reflection of a cholesteric liquid crystal and a quarter wavelength plate (λ / 4 plate), a scattering film using anisotropic scattering by the polarization direction, or the like is used. it can. Moreover, the said optical film can also be combined with a wire grid type polarizer, for example.

  In practical use, the laminated polarizing plate may further contain other optical layers in addition to the laminated retardation plate and the polarizer of the present invention. Examples of the optical layer include conventionally known various optical layers used for forming a liquid crystal display device and the like such as a polarizing plate, a reflecting plate, a transflective plate, and a brightness enhancement film as shown below. One kind of these optical layers may be used, two or more kinds 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 as an integrated polarizing plate having an optical compensation function, for example, and is suitable for use in various image display devices such as being disposed on the surface of a liquid crystal cell. 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. The reflective polarizing plate further includes a reflective plate on the laminated polarizing plate of the present invention, and the transflective polarizing plate further includes a semi-transmissive reflective plate stacked on the laminated polarizing plate of the present invention.

  The reflective polarizing plate 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) of a type that reflects incident light from the viewing side (display side). Such a reflective polarizing plate, for example, has an advantage that the liquid crystal display device can be thinned because the built-in light source such as a backlight can be omitted.

The reflective polarizing plate can be produced by a conventionally known method such as a method of forming a reflective plate made of metal or the like on one surface of a polarizing plate exhibiting the elastic modulus. Specifically, for example, one surface (exposed surface) of the transparent protective layer in the polarizing plate is mat-treated as necessary, and a metal foil or a vapor deposition film made of a reflective metal such as aluminum is formed on the surface as a reflection plate. The reflective polarizing plate formed as follows.

In addition, as described above, a reflective polarizing plate or the like in which a reflecting plate reflecting the fine uneven structure is formed on a transparent protective layer containing fine particles in various transparent resins and having a fine uneven structure on the surface. It is done. A reflector having a fine concavo-convex structure on its surface has an advantage that, for example, incident light can be diffused by irregular reflection to prevent directivity and glaring appearance and to suppress uneven brightness. Such a reflector is, for example, directly on the uneven surface of the transparent protective layer by a conventionally known method such as a vacuum deposition method, an ion plating method, a sputtering method, or a plating method. It can form as a metal vapor deposition film.

In addition, instead of the method of directly forming the reflective plate on the transparent protective layer of the polarizing plate as described above, a reflective sheet having a reflective layer provided on a suitable film such as the transparent protective film is used as the reflective plate. May be. Since the reflective layer in the reflective plate is usually composed of metal, for example, from the viewpoint of preventing the decrease in reflectance due to oxidation, and thus the long-term persistence of the initial reflectance, and the separate formation of a transparent protective layer, etc. The usage form is preferably a state in which the reflective surface of the reflective layer is covered with the film, a polarizing plate or the like.

On the other hand, the transflective polarizing plate has a transflective reflective plate instead of the reflective plate in the reflective polarizing plate. Examples of the transflective reflector include a half mirror that reflects light through a reflective 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, the incident light from the viewing side (display side) is reflected to display an image. In a relatively dark atmosphere, it can be used for a liquid crystal display device of a type that displays an image using a built-in light source such as a backlight built in the back side of the transflective polarizing plate. That is, the transflective polarizing plate can save the energy of using a light source such as a backlight in a bright atmosphere, and can be used with the built-in light source in a relatively dark atmosphere. It is useful for the formation of etc.

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

The brightness enhancement film is not particularly limited, and for example, a linear multi-layer thin film of dielectric material or a multi-layer laminate of thin film films having different refractive index anisotropy transmits linearly polarized light having a predetermined polarization axis, Other light can be used that reflects light. As such a brightness enhancement film, for example, trade name “D-BEF” manufactured by 3M Co., Ltd. may be mentioned. Also, a cholesteric liquid crystal layer, in particular an oriented film of a cholesteric liquid crystal polymer, or a film in which the oriented liquid crystal layer is supported on a film substrate can be used. These reflect the right and left circularly polarized light and transmit the other light. For example, the product name “PCF350” manufactured by Nitto Denko Corporation, the product name “Transmax” manufactured by Merck, etc. can give.

The various laminated polarizing plates as described above may be optical members in which other optical layers are further laminated, for example.

An optical member in which two or more optical layers are laminated in this manner can be formed by a method of sequentially laminating separately, for example, in the manufacturing process of a liquid crystal display device or the like. There are advantages such as excellent quality stability and assembly workability, and improvement in manufacturing efficiency of liquid crystal display devices and the like. For the lamination, various adhesive means such as an adhesive layer can be used as described above.

The various polarizing plates as described above preferably have a pressure-sensitive adhesive layer or an adhesive layer because they can be easily laminated on other members such as a liquid crystal cell. It can be placed on one or both sides of the plate. The material of the adhesive layer is not particularly limited, and a conventionally known material such as an acrylic polymer can be used. In particular, foaming and peeling due to moisture absorption are prevented, optical characteristics are deteriorated due to a difference in thermal expansion, and a liquid crystal cell is warped. For example, it is preferable to form a pressure-sensitive adhesive layer having a low moisture absorption rate and excellent heat resistance, for example, from the viewpoints of prevention, and hence formability of a liquid crystal display device having high quality and excellent durability. Moreover, the adhesion layer etc. which contain microparticles | fine-particles and show light diffusibility may be sufficient. The pressure-sensitive adhesive layer is formed on the surface of the polarizing plate by, for example, adding a solution or a melt of various pressure-sensitive adhesive materials directly to a predetermined surface of the polarizing plate by a developing method such as casting or coating. In the same manner, a pressure-sensitive adhesive layer is formed on a separator, which will be described later, and transferred to a predetermined surface of the polarizing plate. Such a layer may be formed on any surface of the polarizing plate, for example, on the exposed surface of the retardation plate in the polarizing plate.

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

  For example, the pressure-sensitive adhesive layer may be a single layer or a laminate. As the laminate, for example, a laminate in which different compositions and different types of single layers are combined can be used. Moreover, when arrange | positioning on the both surfaces of the said polarizing plate, the same adhesive layer may respectively be sufficient, for example, a different composition and a different kind of adhesive layer may be sufficient.

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.

  As the pressure-sensitive adhesive that forms the pressure-sensitive adhesive layer, for example, one that is excellent in optical transparency and exhibits appropriate wettability, cohesiveness, and adhesive pressure-sensitive adhesive properties 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 property of the pressure-sensitive adhesive layer is, for example, the degree of cross-linking depending on the composition and molecular weight of the base polymer forming the pressure-sensitive adhesive layer, the crosslinking method, the content ratio of the crosslinkable functional group, the blending ratio of the crosslinking agent, and the like. It can be suitably carried out by a conventionally known method such as adjusting the molecular weight.

Each layer such as the above-described laminated retardation plate, polarizing plate, polarizing film, transparent protective layer, optical layer, and pressure-sensitive adhesive layer forming various optical members (various polarizing plates in which optical layers are stacked) is, for example, Further, it may be provided with ultraviolet absorbing ability by appropriately treating with an ultraviolet absorber such as a salicylic acid ester compound, a benzophenone compound, a benzotriazole compound, a cyanoacrylate compound, or a nickel complex compound.

As described above, the laminated retardation plate of the present invention and the laminated polarizing plate provided with the same are preferably used for forming various devices such as a liquid crystal display device. For example, the laminated retardation plate of the present invention and the A laminated polarizing plate is arranged on one side or both sides of a liquid crystal cell to form a liquid crystal panel, which can be used for a liquid crystal display device of a reflective type, a transflective type, a transmissive / reflective type or the like.

  The type of the liquid crystal cell forming the liquid crystal display device can be arbitrarily selected, for example, an active matrix drive type represented by a thin film transistor type, a simple matrix drive type represented by a twist nematic type or a super twist nematic type. Various types of liquid crystal cells can be used. Among these, the optical film and the polarizing plate of the present invention are extremely useful for optical compensation of VA (Vertical Aligned) cells, and are very useful as viewing angle compensation films for VA mode liquid crystal display devices. It is.

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

Moreover, when providing a polarizing plate and an optical member on both surfaces of a liquid crystal cell, the laminated phase difference plate and laminated polarizing plate of the present invention may be disposed on at least one surface, and they may be of the same type or different. May be. Furthermore, when forming the liquid crystal display device, for example, appropriate components such as a prism array sheet, a lens array sheet, a light diffusing plate, and a backlight can be arranged in one or more layers 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. In the case of including a light source, the light source is not particularly limited. However, for example, a planar light source that emits polarized light is preferable because light energy can be used effectively.

  As an example of the liquid crystal panel of the present invention, for example, it has a liquid crystal cell, a laminated retardation plate of the present invention, a polarizer and a transparent protective layer, and the laminated retardation plate is laminated on one surface of the liquid crystal cell. A polarizer and a transparent protective layer are laminated in this order on the other surface of the laminated retardation plate. The liquid crystal cell has a configuration in which liquid crystal is held between two liquid crystal cell substrates. The laminated retardation plate is a laminate of the optically anisotropic layer (A) and the optically anisotropic layer (B) as described above, and any surface may face the polarizer.

In the liquid crystal display device of the present invention, for example, a diffusion plate, an antiglare layer, an antireflection film, a protective layer and a protective plate are further arranged on the viewing-side optical film (laminated polarizing plate), or the liquid crystal in the liquid crystal panel. A compensation retardation plate or the like can be appropriately disposed between the cell and the polarizing plate.

  The laminated phase difference plate of the present invention and the laminated polarizing plate provided with the same are not limited to the liquid crystal display device as described above. For example, a self-luminous type such as an organic electroluminescence (EL) display, PDP, FED, etc. It can also be used for display devices. When used for a self-luminous flat display, for example, circular polarization can be obtained by setting the in-plane retardation value Δnd of the laminated retardation plate of the present invention or the laminated polarizing plate to λ / 4. It can be used as an antireflection filter.

  Hereinafter, an electroluminescence (EL) display device including the laminated retardation plate of the present invention and the laminated polarizing plate will be described. The EL display device of the present invention only needs to have the laminated retardation plate of the present invention or the laminated polarizing plate provided with the same, and may be either organic EL or inorganic EL.

  In recent years, it has been proposed to use, for example, an optical film such as a polarizer or a polarizing plate together with a λ / 4 plate in an EL display device as an antireflection from an electrode in a black state. The laminated phase difference plate and the laminated polarizing plate of the present invention emit light of natural light in the front direction, particularly when the EL layer emits linearly polarized light, circularly polarized light or elliptically polarized light. This is very useful when the outgoing light in the oblique direction is partially polarized.

  First, a general organic EL display device will be described here. The organic EL display device generally has a light emitter (organic EL light emitter) in which a transparent electrode, an organic light emitting layer, and a metal electrode are laminated 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, or the like. Various combinations such as a laminate of a light-emitting layer and an electron injection layer made of a perylene derivative, or a laminate of the hole injection layer, the light-emitting layer, and the electron injection layer can be 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 generated 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 recombination of holes and electrons is the same as that of a general diode, and current and emission intensity show strong nonlinearity with rectification with respect to applied voltage.

  In the organic EL display device, in order to extract light emitted from the organic light emitting layer, at least one of the electrodes needs to be transparent. 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 metal electrodes such as Mg—Ag and Al—Li are used.

  In the organic EL display device having such a configuration, the organic light emitting layer is preferably formed of an extremely thin film having a thickness of about 10 nm, for example. This is because the organic light-emitting layer transmits light almost completely as in the transparent electrode. As a result, at the time of non-light emission, the light incident from the surface of the transparent substrate, transmitted through the transparent electrode and the organic light emitting layer, and reflected by the metal electrode again returns to the surface side of the transparent substrate. For this reason, 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 is, for example, an organic EL display device including the organic EL light emitting device including a transparent electrode on a front surface side of the organic light emitting layer and a metal electrode on a back surface side of the organic light emitting layer. It is preferable that the laminated phase difference plate of the present invention and the laminated polarizing plate are disposed on the surface of the transparent electrode, and it is preferable that a λ / 4 plate is disposed between the polarizing plate and the EL element. Thus, by arranging the laminated phase difference plate and laminated polarizing plate of the present invention, an organic EL display device having an effect of suppressing reflection from the outside and improving the visibility can be obtained. Moreover, it is preferable that a phase difference plate is further disposed between the transparent electrode and the optical film.

The retardation plate and the polarizing plate, for example, have a function of polarizing light incident from the outside and reflected by the metal electrode, so that the effect of preventing the mirror surface of the metal electrode from being visually recognized by the polarization action. is there. In particular, if a quarter-wave plate is used as a retardation plate and the angle formed by the polarization direction of the polarizing plate and the retardation plate is adjusted to π / 4, the mirror surface of the metal electrode is completely shielded. can do. That is, only the linearly polarized light component of the external light incident on the organic EL display device is transmitted by the polarizing plate. The linearly polarized light becomes generally elliptically polarized light by the retardation plate, but becomes circularly polarized light particularly when the retardation plate is a quarter wavelength plate and the angle is π / 4.

  For example, this circularly polarized light is transmitted through the transparent substrate, the transparent electrode, and the organic thin film, reflected by the metal electrode, again transmitted through the organic thin film, the transparent electrode, and the transparent substrate, and again 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. .

  EXAMPLES Hereinafter, although this invention is demonstrated further more concretely using an Example and a comparative example, this invention is not limited to a following example. The optical properties and thickness were measured by the following methods.

(Measurement of phase difference value)
Measurement was performed using a phase difference meter (trade name: KOBRA-21ADH manufactured by Oji Scientific Instruments) based on the parallel Nicol rotation method (measurement wavelength: 610 nm).

(Thickness measurement)
Measurement was performed using an Anritsu brand name digital micrometer K-351C type.

(Example A-3)
2,2'-bis (3,4-dicarboxylate diphenyl) hexafluoro propane Contact and 2,2'-bis (trifluoromethyl) -4,4'-polyimide synthesized from diamino biphenyl (weight average molecular weight 59 , 000) was dissolved in cyclohexanone to prepare a 15 wt% polyimide solution. The polyimide solution was applied to a triacetyl cellulose (TAC) film having a thickness of 80 μm, and tenter transverse stretching was performed while drying at a temperature of 180 ° C. for 5 minutes. The stretching ratio was 2.0 times before stretching in the stretching direction. By this stretching, an optical anisotropic layer (B) made of polyimide was formed on the stretched TAC film (optical anisotropic layer (A)), and a laminated retardation plate was obtained. The optically anisotropic layer (A) has a thickness of 67 μm, and its optical properties are Re (A) = 30 nm, Rth (A) = 55 nm, Rth (A) / Re (A) = 1.8. there were. The optically anisotropic layer (B) has a thickness of 5 μm, and its optical characteristics are Re (B) = 40 nm, Rth (B) = 198 nm, Rth (B) / Re (B) = 5. there were.

(Example A-4)
A weight average molecular weight of 60,000 synthesized from 4,4'-bis (3,4-dicarboxyphenyl) -2,2-diphenylpropane dianhydride and 2,2'-dichloro-4,4-diaminobiphenyl The polyimide was dissolved in cyclopentanone to prepare a 20% by weight polyimide solution. This polyimide solution was applied to a TAC film having a thickness of 80 μm, and tenter transverse stretching was performed while drying at a temperature of 180 ° C. for 5 minutes. The stretching ratio was 1.1 times before stretching in the stretching direction. By this stretching, an optical anisotropic layer (B) made of polyimide was formed on the stretched TAC film (optical anisotropic layer (A)), and a laminated retardation plate was obtained. The optical anisotropic layer (A) had a thickness of 74 μm, and its optical characteristics were Re (A) = 25 nm, Rth (A) = 50 nm, Rth (A) / Re (A) = 2. . The optically anisotropic layer (B) has a thickness of 6 μm, and its optical characteristics are Re (B) = 38 nm, Rth (B) = 220 nm, Rth (B) / Re (B) = 44. there were.

(Comparative Example A-1)
The norbornene film having a thickness of 100 μm was subjected to tenter transverse stretching at 175 ° C. The draw ratio was 1.8 times the length before drawing in the drawing direction. As a result, an optical anisotropic layer (A) having a thickness of 88 μm, Re (A) = 252 nm, Rth (A) = 252 nm, and Rth (A) / Re (A) = 1.0 was obtained. On the other hand, a norbornene film having a thickness of 100 μm was similarly stretched 1.5 times to obtain a thickness of 95 μm, Re (B) = 180 nm, Rth (B) = 181 nm, Rth (B) / Re (B) = 1.0. An optically anisotropic layer (B) was obtained. An acrylic adhesive having a thickness of 15 μm is applied to the optical anisotropic layer (A), and the in-plane slow axes of the optical anisotropic layer (A) and the optical anisotropic layer (B) are orthogonal to each other. I stuck together. Thus, a laminated retardation plate (nx>ny> nz) was produced.

  The thickness, in-plane retardation value (Re), and thickness direction retardation (Rth) of the laminated retardation plate obtained in Examples A-3 and 4 and Comparative Example A-1 were measured. These results are shown in Table 1.

(Table 1)
Example A-3 Example A-4 Comparative Example A-1
(Optically anisotropic layer A)
d (A) μm 67 74 88
Re (A) nm 30 25 252
Rth (A) nm 55 50 252
Rth (A) / Re (A) 1.8 2.0 1.0
(Optically anisotropic layer B)
d (B) μm 5 6 95
Re (B) nm 40 38 180
Rth (B) nm 198 220 181
Rth (B) / Re (B) 5.0 44.0 1.0
(Laminated retardation plate)
d μm 72 80 183
Re nm 70 63 72
Rth nm 253 270 252
Rth-Re 183 207 180

  As shown in Table 1, the laminated retardation plate of Comparative Example A-1 using a norbornene polymer as the optically anisotropic layer (B) has a thickness of 183 μm in order to obtain optical properties similar to those of the examples. It became necessary. On the other hand, according to the laminated phase difference plate of each Example using polyimide as the optically anisotropic layer (B), not only sufficient optical characteristics were obtained, but also two minutes of Comparative Example A-1. A reduction of about 1 was achieved.

(Example B)
The laminated phase difference plate of this invention was manufactured, and the laminated polarizing plate shown in FIGS . 1-3 was further manufactured using this. In these drawings, the same portions are denoted by the same reference numerals.

(Example B-5)
In this example, a laminated polarizing plate 50 having the form shown in FIG. 1 was produced. A polyimide (weight average molecular weight 59000) synthesized from 2,2′-bis (3,4-dicarbodiphenyl) hexafluoropropane and 2,2′-bis (trifluoromethyl) -4,4′-diaminobiphenyl It melt | dissolved in cyclohexanone and prepared the 15 weight% polyimide solution. This polyimide solution was applied to a TAC film having a thickness of 80 μm, and tenter transverse stretching was performed at a stretching ratio of 1.3 times while drying at a temperature of 190 ° C. for 5 minutes. Thus, a laminated retardation film 31 having a total thickness of 66 μm, in which a polyimide film (optical anisotropic layer (B) 11b) having a thickness of 6 μm is laminated on a stretched TAC film (optical anisotropic layer (A) 11a) having a thickness of 60 μm. Got. And, through the PVA adhesive layer 15 having a thickness of 5 μm, the TAC film 12 having a thickness of 80 μm is provided on one side of the polarizing layer 13, and the laminated retardation plate 31 is provided on the other side of the optical anisotropic layer (A) 11 a. Adhesion was performed so as to be on the polarizing layer 13 side to obtain a wide viewing angle laminated polarizing plate having a thickness of 183 μm. The polarizing layer was obtained by stretching a polyvinyl alcohol (PVA) film having a thickness of 80 μm five times in an iodine aqueous solution and then drying.

(Example B-6)
In this example, a laminated polarizing plate 60 having the form shown in FIG. 2 was produced. A wide viewing angle with a thickness of 176 μm, as in Example B-5, except that the laminated retardation plate 31 was adhered to the polarizing layer 13 so that the optically anisotropic layer (B) 11b was on the polarizing layer 13 side. The laminated laminated polarizing plate 60 was obtained.

(Example B-8)
In this example, a laminated polarizing plate 80 having the form shown in FIG. 3 was produced. A weight average molecular weight of 65,000 synthesized from 4,4'-bis (3,4-dicarboxyphenyl) -2,2-diphenylpropane dianhydride and 2,2'-dichloro-4,4-diaminobiphenyl The polyimide was dissolved in cyclopentanone to prepare a 20% by weight polyimide solution. This polyimide solution was applied to a TAC film having a thickness of 80 μm, and tenter transverse stretching was performed while drying at a temperature of 200 ° C. for 5 minutes. The stretching ratio was 1.5 times before stretching in the stretching direction. As a result, a laminated retardation plate having a total thickness of 60 μm is formed by laminating a 6 μm thick polyimide film (optical anisotropic layer (B)) on a stretched TAC film (optical anisotropic layer (A)) having a thickness of 54 μm. It was done. Furthermore, the laminated phase difference plate is interposed via a polyvinyl alcohol (PVA) pressure-sensitive adhesive layer 15 so that the optically anisotropic layer (A) faces one side of the polarizing layer similar to Example B-5. Further, the TAC film 12 having a thickness of 80 μm was bonded to the other surface of the polarizing layer through a PVA adhesive layer. As a result, a wide viewing angle laminated polarizing plate having a thickness of 170 μm was obtained.

(Comparative Example B-1)
A TAC film having a thickness of 80 μm, Re (A) 0.9 nm, Rth (A) 59 nm, and Rth (A) / Re (A) 66 was used as the optically anisotropic layer (A). On top of this, the same polyimide solution as in Example B-5 was applied and dried at 130 ° C. for 5 minutes to form an optically anisotropic layer (B) on the optically anisotropic layer (A). A laminated phase difference plate having a thickness of 85 μm and nx≈ny> nz was produced. Furthermore, a 5 μm-thick polyvinyl alcohol (PVA) pressure-sensitive adhesive layer is used so that the optically anisotropic layer (A) is opposed to one side of the polarizing layer similar to Example B-5. Further, a TAC film having a thickness of 80 μm was adhered to the other surface of the polarizing layer via a PVA adhesive layer (thickness: 5 μm). As a result, a wide viewing angle laminated polarizing plate having a thickness of 170 μm was obtained.

(Comparative Example B-2)
The same polyimide solution as in Example B-5 was coated on a polyester film, dried at 130 ° C. for 5 minutes, and subjected to tenter transverse stretching at 160 ° C. by 1.1 times. By removing the polyester film, an optically anisotropic layer (B) made of polyimide was obtained. The optically anisotropic layer (B) had a thickness of 6 μm, Re (B) 55 nm, Rth (B) 240 nm, and Rth (B) / Re (B) 4.4. Further, the optically anisotropic layer (B) is bonded to one side of the polarizing layer similar to Example B-5 via a polyvinyl alcohol (PVA) pressure-sensitive adhesive layer having a thickness of 5 μm. A TAC film having a thickness of 80 μm was adhered to the other surface via an acrylic pressure-sensitive adhesive (thickness: 15 μm). Thereby, a wide viewing angle laminated polarizing plate not including the optically anisotropic layer (A) was obtained.

(Comparative Example B-3)
A TAC film having a thickness of 80 μm was stretched by a tenter at 190 ° C. by 1.4 times to obtain a thickness of 58 μm, Re (A) 40 nm, Rth (A) 46 nm, Rth (A) / Re (A) 1.2. An optically anisotropic layer (A) was obtained. On the other hand, the same polyimide solution as in Example B-5 was coated on a polyester film, dried at 130 ° C. for 5 minutes, and subjected to 1.2 times free end longitudinal stretching at 160 ° C. An optically anisotropic layer (B) made of polyimide was formed thereon. The optically anisotropic layer (B) had a thickness of 6 μm, Re (B) 170 nm, Rth (B) 200 nm, and Rth (B) / Re (B) 1.2. A laminated phase difference plate is obtained by adhering both with an acrylic pressure-sensitive adhesive having a thickness of 15 μm so that the optically anisotropic layer (A) and the optically anisotropic layer (B) face each other, and then removing the polyester film. Got. This laminated retardation plate had a thickness of 64 μm, Re of 210 nm, Rth of 246 nm, Rth / Re of 1.2, and (Rth−Re) of 36 nm. The laminated phase difference plate is bonded via a PVA pressure-sensitive adhesive layer having a thickness of 5 μm so that the optically anisotropic layer (A) is opposed to one side of the polarizing layer similar to Example B-5, A TAC film having a thickness of 80 μm was bonded to the other surface of the polarizing layer via a PVA adhesive layer (thickness: 5 μm). Thus, a wide viewing angle laminated polarizing plate having a thickness of 189 μm was obtained.

(Comparative Example B-4)
A polarizing layer was obtained in the same manner as in Example B-5.

  Optically anisotropic layer (A), optically anisotropic layer (B) and laminated phase difference in wide viewing angle laminated polarizing plate obtained in Examples B-5, 6, 8 and Comparative Examples B-1 to B-3 The plate was measured for in-plane retardation value, thickness direction retardation and the like as described above. The results are shown in Table 2 below.

(Table 2)
Examples Comparative examples
B-5 B-6 B-8 B-1 B-2 B-3
(Optically anisotropic layer A)
d (A) μm 60 60 54 80-58
Re (A) nm 30 30 33 0.9 -40
Rth (A) nm 38 38 36 59-46
Rth (A) / Re (A) 1.3 1.3 1.1 66-1.2
(Optically anisotropic layer B)
d (B) μm 6 6 6 5 6 6
Re (B) nm 22 22 25 0.3 55 170
Rth (B) nm 200 200 205 170 240 200
Rth (B) / Re (B) 9.1 9.1 8.2 567 4.4 1.2
(Laminated retardation plate)
d μm 66 66 60 85-64
Re nm 52 52 59 1 55 210
Rth nm 238 238 240 229 240 246
Rth-Re 186 186 181 228 185 36

  Viewing angle characteristics of the wide viewing angle laminated polarizing plates obtained in Examples B-5, 6, 8 and Comparative Examples B-1 to B-3 and the polarizing plate obtained in Comparative Example B-4 were evaluated. A polarizing plate was placed on both sides of the VA type liquid crystal cell so that the transmission axes were orthogonal to each other to produce a liquid crystal display device. In addition, the wide viewing angle laminated polarizing plate of Example was arrange | positioned so that a laminated phase difference plate might become the liquid crystal cell side. The viewing angle at which the Co (contrast) on the display screen of the liquid crystal display device was 10 or more was measured.

The contrast was calculated by the following method. A white image and a black image are displayed on the liquid crystal display device, and the front, top, bottom, left, right, diagonal 45 ° -225 °, and diagonal 135 ° -315 are displayed according to the product name Ez contrast 160D (manufactured by ELDIM). The Y value, x value, and y value of the XYZ display system in the ° direction were measured. The contrast “Y _w / Y _B ” at each viewing angle was calculated from the Y value (Y _w ) in the white image and the Y value (Y _B ) in the black image . Shows the range of viewing angles the contrast exhibits 10 or more in the following Table 3. Moreover, the display screen of each said liquid crystal display device was observed visually, and the presence or absence of coloring of the said laminated phase difference plate was evaluated. These results are also shown in Table 3 below.

(Table 3)
Visual angle (°) Coloring
Up / Down Left / Right Diagonal (45 ° -225 °) Diagonal (135 ° -315 °)
Example B-5 ± 80 ± 80 ± 65 ± 65 None Example B-6 ± 80 ± 80 ± 65 ± 65 None Comparative Example B-1 ± 80 ± 80 ± 40 ± 40 None Comparative Example B-2 ± 80 ± 80 ± 55 ± 55 Yes Comparative Example B-3 ± 80 ± 80 ± 40 ± 40 Yes
Comparative Example B-4 ± 80 ± 80 ± 35 ± 35 None

  According to the laminated polarizing plate including the laminated retardation plate of the present invention as shown in Table 2, a liquid crystal display device with a wider viewing angle was obtained as shown in Table 3 than in each comparative example. In Comparative Example B-1, since the in-plane retardation is not sufficiently compensated for by the optically anisotropic layer (A), the in-plane retardation (Re) is smaller than 10 nm, and Comparative Example B-3 has (Rth− Since Re) is smaller than 50 nm, the viewing angle characteristics in the diagonal direction are inferior, and coloring was also confirmed for Comparative Example B-3. Further, Comparative Example B-2 consisting only of the polyimide optically anisotropic layer (B) does not show excellent diagonal viewing angle characteristics as in the examples, and the optically anisotropic layer (B) alone has a thickness. Since the directional phase difference was increased, coloring was also confirmed. From this, it can be said that the use of the wide viewing angle laminated polarizing plate according to the present invention can provide a liquid crystal display device with a high quality display which is thinner and more visible than the conventional one.

  As described above, the multilayered retardation plate of the present invention has a wide viewing angle characteristic when applied to various image display devices because Re is 10 nm or more and (Rth-Re) is 50 nm or more. In addition, since the thickness can be reduced, it is very useful.

It is sectional drawing which shows an example of a laminated polarizing plate in the Example of this invention. It is sectional drawing which shows an example of the laminated polarizing plate in the other Example of this invention. It is sectional drawing which shows an example of a laminated polarizing plate in the further another Example of this invention.

Explanation of symbols

50, 60, 80 laminated polarizing plate 11 laminated retardation plate 11a optical anisotropic layer (A)
11b Optical anisotropic layer (B)
12 Transparent protective layer 13 Polarizing layer 14 Adhesive layer 15 Adhesive layer

Claims (5)

A laminated retardation plate comprising at least two optically anisotropic layers,
An optically anisotropic layer (A) made of a polymer and at least one non-liquid crystalline polymer selected from the group consisting of polyamide, polyimide, polyester, polyaryletherketone, polyetherketone, polyamideimide and polyesterimide. And (B)
The in-plane retardation (Re) represented by the following formula is 10 nm or more,
A method for producing a laminated retardation plate having a thickness direction retardation (Rth) represented by the following formula and a difference (Rth-Re) between the in-plane retardation (Re) of 50 nm or more,
On the polymer optical anisotropic layer (A), the non-liquid crystalline polymer solution is applied to form a coating film, and only the optical anisotropic layer (A) is dried while drying the coating film. The optically anisotropic layer (B) is formed by stretching the coating film indirectly by stretching the coating film .
Re = (nx−ny) · d
Rth = (nx−nz) · d
In the above equation, nx, ny, and nz represent the refractive indexes in the X-axis, Y-axis, and Z-axis directions of the laminated phase difference plate, respectively, and the X axis is the maximum in the plane of the laminated phase difference plate. An axial direction indicating a refractive index, the Y axis is an axial direction perpendicular to the X axis in the plane, and the Z axis is a thickness direction perpendicular to the X axis and the Y axis, and d Indicates the thickness of the laminated retardation plate.   A substrate is used in place of the optically anisotropic layer (A), the non-liquid crystalline polymer solution is applied onto the substrate to form a coating film, and the substrate is dried while the coating film is dried. The optical anisotropic layer (B) is formed by stretching only the material and indirectly stretching the coating film, and bonding the optical anisotropic layer (B) to the optical anisotropic layer (A) Then, the method for producing a laminated phase difference plate according to claim 1, wherein the substrate is peeled off. The method for producing a laminated phase difference plate according to claim 1 or 2, wherein the forming material of the optically anisotropic layer (A) is a polymer exhibiting positive birefringence. The manufacturing method of the laminated phase difference plate as described in any one of Claim 1 to 3 with which the said laminated phase difference plate satisfy | fills the following conditions.
nx> ny> nz
The manufacturing method of the laminated phase difference plate as described in any one of Claim 1 to 4 with which the adhesive layer was further laminated | stacked on at least one outermost layer in the said laminated phase difference plate.

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