JP4481281B2 - Tilted optical compensation film, method for producing the same, and liquid crystal display device using the same - Google Patents

Description

  The present invention relates to a tilted optical compensation film used for improving viewing angle characteristics, a method for producing the same, and various image display devices using the same.

  Conventionally, in a liquid crystal display device, various retardation films are used for optical compensation, and for example, a birefringent layer formed from a polymer having negative birefringence is used. As the polymer having negative birefringence, for example, polyimide and the like are disclosed in various documents (for example, see Patent Documents 1 to 7). However, the negative birefringent layer can be used as a tilted optical compensation film in a liquid crystal display device in which the display method is a vertical alignment (VA) mode, for example, but in a twisted nematic (TN) mode liquid crystal display device, There is a problem that the effect as a tilted optical compensation film is insufficient.

  On the other hand, as a tilted optical compensation film useful for a TN mode liquid crystal display device, for example, a film containing a low molecular liquid crystal tilted and aligned in a polymer matrix (for example, see Patent Document 8), or aligned on a support. There has been reported a film in which a film is formed, a discotic liquid crystal is tilted on the film, and the liquid crystal is polymerized (see, for example, Patent Documents 9 and 10).

However, although there are many reports on tilted optical compensation films for TN mode in which such a liquid crystal material is tilt-aligned, for example, selection of a liquid crystal material (e.g., tilt alignment using the difference in surface energy at the air interface is easy). The selection of the liquid crystal material) and the control of the tilt angle of the liquid crystal material (control of the tilt angle using a surfactant) are necessary, and the manufacturing method is complicated, such as the necessity of an alignment substrate, and the control factors are diverse. There is also a problem that it is difficult to change the tilt angle and the phase difference (see, for example, Patent Document 11).
US Pat. No. 5,344,916 US 5,395,918 US 5,480,964 US 5,580,950 US 5,694,187 US 5,750,641 US 6,074,709 Japanese Patent No. 2565644 Japanese Patent No. 2692035 Japanese Patent No. 2802719 JP-A-12-105315

  Therefore, an object of the present invention is to provide a new tilted optical compensation film, not a tilted optical compensation film using a conventional liquid crystal material. Specifically, the tilt is useful for a TN mode liquid crystal display device or the like. An orientation-type tilted optical compensation film is provided.

  In order to achieve the above object, the present invention is an optical compensation film containing a non-liquid crystal polymer, and includes the following first and second inclined optical compensation films.

The first inclined optical compensation film of the present invention is
An optical compensation film comprising a non-liquid crystal polymer,
The non-liquid crystal polymer is tilted;
When the normal of the optical compensation film surface is 0 ° and the angle between the normal and the measurement axis is the measurement angle (0 °),
The phase difference value measured from the measurement axis direction is centered on the phase difference value at 0 °, and the change in the phase difference value is asymmetric between the + side and the − side,
And,
The birefringence (Δn) represented by the following formula is in the range of 0.001 to 0.5.

  Δn = [[(nx + ny) / 2] −nz] · d / d

  In the above formula, Δn represents the birefringence of the tilted optical compensation film, nx, ny and nz represent the refractive indexes in the X-axis, Y-axis and Z-axis directions of the tilted optical compensation film, respectively, and the X-axis Is the axial direction showing the maximum refractive index in the plane of the tilted optical compensation film, the Y axis is the axial direction perpendicular to the X axis in the plane, and the Z axis is the X direction The thickness direction perpendicular to the axis and the Y axis is shown, and d denotes the thickness of the tilted optical compensation film.

The second tilted optical compensation film of the present invention is an optical compensation film containing a non-liquid crystal polymer,
The non-liquid crystal polymer is tilted;
When the normal of the optical compensation film surface is 0 ° and the angle between the normal and the measurement axis is a measurement angle (including 0 °),
The phase difference value measured from the measurement axis direction is centered on the phase difference value at 0 °, and the change in the phase difference value is asymmetric between the + side and the − side,
And,
The non-liquid crystal polymer is at least one polymer selected from the group consisting of polyamide, polyimide, polyester, polyetherketone, polyamideimide and polyesterimide.

  ADVANTAGE OF THE INVENTION According to this invention, a new inclination optical compensation film useful especially for liquid crystal display devices, such as NT mode, can be provided, without using liquid crystal material. Further, since it is a non-liquid crystal polymer, it is not affected by the orientation of the substrate, so the type of the substrate is not limited. Furthermore, even after the non-liquid crystal polymer is tilted and oriented, it can be stretched and contracted, so that the design of optical properties can be further changed. Therefore, the application can be expanded and it is very useful as a retardation film.

  As a result of diligent research, the present inventors have selected a non-liquid crystal polymer instead of a liquid crystal material as a forming material, and by using a non-liquid crystal polymer such as polyimide among the non-liquid crystal polymers, a tilting optical system that is completely different from the conventional one. The inventors have newly found that a compensation film can be formed, and have reached the present invention. As long as the non-liquid crystal polymer is tilted and the tilted optical compensation film satisfies the above conditions, for example, a TN mode liquid crystal display can be used as in the case of a tilted optical compensation film (tilt retardation film) made of a conventional liquid crystal material. Useful for devices and the like. Furthermore, since the tilted optical compensation film of the present invention is formed from a non-liquid crystal polymer, it is different from the conventional liquid crystal material that is solidified. Optical properties such as phase difference can be further changed by applying shrinkage or the like. For this reason, it is possible to adjust the optical characteristics according to the application, such as imparting more excellent optical characteristics, etc., and can be used for a wider range of applications than the conventional tilted optical compensation film, leading to cost reduction. . Further, by using the above-described polyimide or the like as the non-liquid crystal polymer, the birefringence (Δn) in the above-described range can be satisfied, so that the visual compensation effect such as good contrast at a wide viewing angle is excellent. Therefore, the optical compensation film of the present invention can be used as a new retardation film useful for various image display devices including liquid crystal display devices.

  In the present invention, the trajectory of the measurement axis including the normal line is the same plane, and the inclination direction of the measurement axis inclined from the normal line is not particularly limited.

Next, the method for producing a tilted optical compensation film of the present invention comprises applying at least one non-liquid crystal polymer selected from the group consisting of polyamide, polyimide, polyester, polyetherketone, polyamideimide and polyesterimide on a substrate. Forming a coating film, and forming a tilted optical compensation film by tilt-aligning the non-liquid crystal polymer in the coating film,
The method for tilting and aligning the non-liquid crystal polymer is a method for manufacturing a tilted optical compensation film, in which an external force is applied to the coating film so that the non-liquid crystal polymer is tilt-aligned.

  If the non-liquid crystal polymer as described above is different from the conventional liquid crystalline material due to its own properties, regardless of the orientation of the base material, the molecules are aligned and optically negative due to their own properties. A coating film exhibiting uniaxiality (nx> nz) and (ny> nz) can be formed. Therefore, the substrate is not limited to the substrate on which the alignment substrate or the alignment film is formed. In addition, the non-liquid crystal polymer constituting the coating film can be tilted and aligned only by applying an external force to the coating film formed in this way. By such a method, a new tilted optical compensation film having excellent optical characteristics as described above can be obtained.

The tilted optical compensation film of the present invention is an optical compensation film containing a non-liquid crystal polymer as described above, and the non-liquid crystal polymer is tilted and oriented,
When the normal of the optical compensation film surface is 0 ° and the angle between the normal and the measurement axis is the measurement angle (0 °),
The phase difference value measured from the measurement axis direction is asymmetric in the change of the phase difference value between the + side and the − side with the phase difference value at 0 ° as the center. And the 1st inclination optical compensation film of this invention is further characterized by birefringence ((DELTA) n) represented by a following formula being the range of 0.001-0.5.

  Δn = [[(nx + ny) / 2] −nz] · d / d

  In the above formula, Δn represents the birefringence of the tilted optical compensation film, nx, ny and nz represent the refractive indexes in the X-axis, Y-axis and Z-axis directions of the tilted optical compensation film, respectively, and the X-axis Is the axial direction showing the maximum refractive index in the plane of the tilted optical compensation film, the Y axis is the axial direction perpendicular to the X axis in the plane, and the Z axis is the X direction The thickness direction perpendicular to the axis and the Y axis is shown, and d denotes the thickness of the tilted optical compensation film. In the second tilted optical compensation film of the present invention, the non-liquid crystal polymer is at least one polymer selected from the group consisting of polyamide, polyimide, polyester, polyetherketone, polyamideimide and polyesterimide. It is characterized by.

  In the present invention, “the phase difference value measured from the direction of the measurement axis is asymmetric in the change of the phase difference value between the + side and the − side with the phase difference value at 0 ° as the center. ", For example, a graph obtained when the phase difference value at each measurement angle is plotted on the horizontal axis and the measurement angle is plotted on the vertical axis, as shown in FIG. 1, at a measurement angle of 0 ° (normal line). A state in which the vertical axis (the dotted line in the figure) is asymmetrical.

  The measurement angle is not particularly limited, but is preferably, for example, −50 to + 50 °. This is because when the phase difference is measured by actually tilting the sample of the tilted optical compensation film, the phase difference can be measured with higher accuracy within the above range. This measurement angle is a condition for measuring the phase difference of the present invention, and does not limit the present invention.

  In the present invention, it is preferable that the maximum value or the minimum value of the phase difference value is a phase difference value when the measurement angle is on the + side or − side. That is, the phase difference value in the normal (0 °) direction is preferably not the maximum or minimum value.

  In the tilted optical compensation film of the present invention, examples of the shape of the graph include a concave curve, a convex curve, a right-up curve, and a right-down curve as shown in FIG. When the graph shape is a concave curve, the vertex is the maximum phase difference value, and when the graph shape is a convex curve, the vertex is the minimum phase difference value. In the case of a curve that rises to the right, the measurement value at the maximum measurement angle (for example, + 50 °) is the maximum phase difference value, and the measurement value at the minimum measurement angle (for example, −50 °) is the minimum phase difference value. In this case, the measurement value at the maximum measurement angle is the minimum phase difference value, and the measurement value at the minimum measurement angle is the maximum phase difference value.

  In the present invention, the measurement axis includes a normal line and an axis inclined from the normal line, and the inclination direction is not particularly limited. For example, the axis inclined from the normal line is a slow axis of the inclined optical compensation film. It may be inclined in the direction or may be inclined in the fast axis direction of the inclined optical compensation film.

  In the present invention, the birefringence (Δn) represented by the above formula is preferably in the range of 0.001 to 0.5 because the thickness can be sufficiently reduced. The birefringence is preferably in the range of 0.001 to 0.2, particularly preferably 0.002 to 0.15, because a thin tilted optical compensation film having further excellent productivity can be obtained. Range.

  Although other optical characteristics are not particularly limited, the in-plane retardation (Δnd) represented by the following formula is, for example, in the range of 5 to 200 nm, preferably 10 to 150 nm. Moreover, the thickness direction phase difference (Rth) represented by a following formula is the range of 20-1000 nm, for example, Preferably it is 30-800 nm, More preferably, it is 40-500 nm. In the following formula, nx, ny, nz, and d are as described above.

Δnd = (nx−ny) · d
Rth = [[(nx + ny) / 2] −nz] · d

  For example, as described above, the tilt optical compensation film of the present invention is preferably applied to a liquid crystal display device whose display method is a TN (Twisted Nematic) mode or an OCB (Optically Aligned Birefringence) mode. In addition, if the liquid crystal alignment is a monodomain alignment, the display method is not limited, and can be applied to, for example, a VA mode liquid crystal display.

  By disposing the tilted optical compensation film of the present invention in a liquid crystal display device, for example, a region showing a contrast of 10 or higher in a liquid crystal display device whose display method is a TN mode is further expanded by 10 ° or more in the horizontal direction of the display surface. It is preferable to do.

  The contrast can be measured by the following method, for example. First, a sample is placed on a liquid crystal display device together with a polarizing plate, and a white image and a black image are displayed on the liquid crystal display device. For example, according to a trade name Ez contrast 160D (manufactured by ELDIM) or the like, For the left and right, the Y value, x value, and y value of the XYZ display system at a viewing angle of 0 to 70 ° are measured. Then, the contrast at each viewing angle can be calculated from the Y value (Yw) in the white image and the Y value (YB) in the black image.

  The non-liquid crystal polymer in the present invention is optically negative uniaxial (nx> nz) or (ny> nz) due to its own properties regardless of the orientation of the substrate, for example, unlike a liquid crystalline material. Can be formed. For this reason, the non-liquid crystal polymer is aligned by its own properties without using a birefringent base material such as an alignment substrate or a substrate having an alignment film laminated on the surface like conventional liquid crystal materials. It becomes a state. Therefore, although it is not a liquid crystal material, the non-liquid crystal polymer can be tilted and aligned by a process as described later.

  As the non-liquid crystal polymer, for example, it has excellent heat resistance, chemical resistance, transparency, and rigidity, so polyamide, polyimide, polyester, polyaryletherketone, polyetherketone, polyamideimide, polyesterimide, etc. Polymers are preferred. 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 and the like are preferable because high birefringence can be obtained. This is because, when such a high birefringence is exhibited, a large birefringence value can be obtained, and therefore, for example, a comparable compensation effect can be achieved with a thin layer as compared with other polymers. Examples of these polymers include, but are not limited to, for example, U.S. Patent Nos. 5,344,916, 5,395,918, 5,480,964, 5,580,950, Those disclosed in US Pat. Nos. 5,694,187, 5,750,641, 6,074,709 and the like can be used.

  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.

  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, a condensation polymerization product of 9,9-bis (aminoaryl) fluorene and aromatic tetracarboxylic dianhydride disclosed in JP-T-2000-511296, specifically, A polymer containing one or more repeating units represented by the following formula (1) can be used.

In the formula (1), R ³ to R ⁶ are hydrogen, halogen, a phenyl group, 1-4 halogen atoms, or C ₁ ~ ₁₀ alkyl-substituted phenyl, and C ₁ ~ 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).

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 ^{There are 8} groups, and when there are multiple 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, it may be the same or different. R ⁹ are each 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. (Wherein X is halogen), from the group consisting of CO group, O atom, S atom, SO ₂ group, Si (CH ₂ CH ₃ ) ₂ group, and N (CH ₃ ) group, 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 kind of substituent selected from the group consisting of halogen, C _1-3 alkyl group, and C _1-3 halogenated alkyl group. Examples of the halogen include fluorine, chlorine, bromine and iodine. d is an integer from 0 to 2, and e is an integer from 0 to 3.

  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, halogen, C _1-3 alkyl group, C _1-3 halogenated alkyl group, phenyl group, or 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 2,2 ', 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, for example, 2,2′-dibromo-4,4 ′, 5,5′-biphenyltetracarboxylic dianhydride, 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'- Sopropylidene-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 diamines, 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 naphthalene diamine 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, the aromatic diamine includes 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-aminophenol 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'-diaminodiphenyl thioether, 4,4'-diaminodiphenyl sulfone and the like.

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

  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.

  In the formula (8), X ′ represents a substituent, and is the same as X in the formula (7), for example. In 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 R2, an aromatic group selected from the group consisting of the following formulas (9) to (15) is preferable.

In the formula (7), the 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. 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 the material for forming the birefringent layer include polyamides and polyesters described in JP-T-10-508048, and their repeating units are: For example, it can be represented by the following general formula (22).

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 represents, for example, hydrogen, halogen, C _1-3 alkyl group, C _1-3 halogenated alkyl group, an alkoxy group represented by 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, C _1-3 alkyl group, C _1-3 halogenated alkyl group, phenyl group and 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, C _1-3 alkyl group, 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.

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.

The tilted optical compensation film of the present invention may be, for example, only a birefringent layer formed from the tilted non-liquid crystal polymer, or a laminate including another member such as a base material in addition to the birefringent layer. It may be a body.

  In the present invention, the thickness of the birefringent layer formed from the non-liquid crystal polymer is not particularly limited. For example, when applied as a retardation film, the liquid crystal display device can be thinned, and the visual compensation function can be achieved. In order to obtain an excellent and homogeneous film, the range of 0.1 to 50 μm is preferable, more preferably 0.5 to 30 μm, and particularly preferably 1 to 20 μm. In addition, the thickness of the tilted optical compensation film of the present invention varies depending on, for example, the case where only the birefringent layer is included as described above and the case where other members such as a base material are included. The range is 50 μm, preferably 1 to 40 μm.

  Below, the manufacturing method of the inclination optical compensation film of this invention is demonstrated. The manufacturing method of the tilted optical compensation film of the present invention is not particularly limited as long as it satisfies the above-described conditions, and examples thereof include the following first and second manufacturing methods.

  The first manufacturing method includes a step of coating the non-liquid crystal polymer on a substrate to form a coating film, and a tilt optical compensation film is formed by tilt-aligning the non-liquid crystal polymer in the coating film. A step of applying an external force to the coating film so that the non-liquid crystal polymer is inclined and aligned. This will be specifically described below.

  First, the non-liquid crystal polymer is applied onto a substrate to form a coating film. As described above, since the non-liquid crystal polymer has the 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. As a base material which produces the phase difference by the said birefringence, a stretched film etc. are mention | raise | lifted, for example, and the thing etc. which the refractive index of the thickness direction was controlled can 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 material of the base material is not particularly limited, but for example, a polymer having excellent transparency is preferable, and a thermoplastic resin is preferable because it is suitable for a stretching process and a shrinking process as described later. Specifically, for example, acetate resin such as triacetyl cellulose (TAC), polyester resin, polyether sulfone resin, polysulfone resin, polycarbonate resin, polyamide resin, polyimide resin, polyolefin resin, acrylic resin, polynorbornene resin, cellulose resin And polyarylate resin, polystyrene resin, polyvinyl alcohol resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyacrylic resin, and mixtures thereof. A liquid crystal polymer or the like can also be used. Further, for example, as described in JP-A-2001-343529 (WO 01/37007), a thermoplastic resin having a substituted imide group or an unsubstituted imide group in the side chain, and a substituted phenyl group in the side chain Alternatively, a mixture of a thermoplastic resin having an unsubstituted phenyl group and a nitrile group can also be used. Specific examples include a resin composition having an alternating copolymer composed of isobutene and N-methylenemaleimide and an acrylonitrile / styrene copolymer. Among these forming materials, a mixture of the above-mentioned thermoplastic resin having a substituted imide group or an unsubstituted imide group in the side chain and a thermoplastic resin having a substituted phenyl group or an unsubstituted phenyl group and a nitrile group in the side chain. Is preferred.

  The thickness of the substrate is not particularly limited, but is, for example, in the range of 5 to 500 μm, preferably in the range of 10 to 200 μm, and particularly preferably in the range of 15 to 150 μm.

  The method for coating the non-liquid crystal polymer on the substrate is not particularly limited. For example, because of excellent workability, a method of coating a polymer solution in which the non-liquid crystal polymer is dissolved in a solvent, etc. Is preferred.

  Although 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 crystal polymer is preferably 5 to 50 parts by weight with respect to 100 parts by weight of the solvent. More preferably, it is 10 to 40 parts by weight.

  The solvent of the polymer solution is not particularly limited as long as the non-liquid crystal polymer can be dissolved, and can be appropriately determined according to the type of the non-liquid crystal polymer. 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. Specifically, additives such as a silane coupling agent and an acrylic copolymer are used for improving the adhesion to the substrate and other members.

  In addition, the polymer solution may contain other different resins as long as, for example, the orientation of the non-liquid crystal polymer is not significantly reduced. 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.

  Next, the non-liquid crystal polymer is tilted and aligned by applying an external force to the coating film on the substrate. The tilted optical compensation film can be formed on the substrate by tilting in this way. The method of applying the external force is not particularly limited as long as the non-liquid crystal polymer is tilted and aligned, and examples thereof include a method of blowing air on the coating film.

  Conditions for blowing air to the coating film are not particularly limited and can be appropriately determined according to the physical properties of the polymer solution, for example, viscosity, etc., for example, when the coating film is fixed, It is preferable to blow the wind so that the angle is 10 to 80 ° from the normal of the surface, and more preferably the angle is 20 to 70 °.

  Also, the time for blowing the wind is not particularly limited, and can be appropriately determined according to the desired inclination angle of the non-liquid crystal polymer, for example, preferably 5 seconds to 10 minutes per location, more preferably It is 10 seconds to 9 minutes, and particularly preferably 30 seconds to 8 minutes.

  Thus, by applying an external force to the coating film, the non-liquid crystal polymer forming the coating film can be tilted and oriented at, for example, 5 to 50 ° from the normal direction of the coating film. The angle of the tilted orientation can be appropriately determined according to the application, for example.

  The inclination angle of the non-liquid crystal polymer can be calculated as an average inclination angle from the normal direction using, for example, a phase difference meter (trade name KOBRA-21ADH; manufactured by Oji Scientific Instruments).

  Further, after applying an external force to the coating film, a step of solidifying the tilted non-liquid crystal polymer on the substrate may be included. The method for solidifying the non-liquid crystal polymer is not particularly limited. For example, the non-liquid crystal polymer is solidified on the base material by, for example, naturally drying or heat-treating the tilted non-liquid crystal polymer. can do.

  As the conditions for the heat treatment, for example, the heating temperature is preferably in the range of 25 to 300 ° C, more preferably in the range of 50 to 250 ° C, and particularly preferably in the range of 60 to 200 ° C.

  Since the solvent of the polymer solution remaining in the tilted optical compensation film on the substrate may change the optical characteristics over time in proportion to the amount thereof, the remaining amount is 5% or less due to the heating or the like. It is preferable to process so that it may become, More preferably, it is 2% or less, More preferably, it is 0.2% or less.

  Further, in the inclined alignment treatment step, for example, the inclined alignment treatment step and the solidification step may be performed simultaneously by blowing hot air. That is, the non-liquid crystal polymer may be tilted and solidified by performing both steps simultaneously.

  The tilted optical compensation film thus formed may be subjected to, for example, a corona treatment, a dry treatment such as an ozone treatment, a wet treatment such as an alkali treatment, etc., in order to improve adhesion to other members. .

  On the other hand, the second manufacturing method includes a step of coating the non-liquid crystal polymer on a substrate to form a coating film, and a step of tilting and aligning the non-liquid crystal polymer in the coating film, The method of tilting and aligning the non-liquid crystal polymer uses a shrinkable base material (first base material) as the base material, and after forming a coating film on the first base material, Forming a second base material having a different shrinkage from the first base material on the coating film, sandwiching the coating film between the first base material and the second base material, In this method, an external force is applied to the coating film by shrinking both the first base material and the second base material. This will be specifically described below. Unless otherwise specified, the same production can be performed using the same material as that of the first production method.

  Prior to the formation of the coating film, the first base material having the contractibility and the second base material are prepared. As both the base materials, materials having the same shrinkage as those described above can be used as long as they have different shrinkage rates. The second base material may have a contraction rate different from that of the first base material. For example, the second base material may not have contractility.

  The shrinkable base material preferably has shrinkage in one direction within the plane. Such shrinkability can be imparted, for example, by subjecting an untreated substrate to a stretching treatment. Thus, contraction force is generated in the direction opposite to the stretching direction by previously stretching the substrate. Moreover, if it is a base material which has a contractibility originally, it may be used untreated and may be contracted by heating.

  Although the thickness of the said base material before extending | stretching is not restrict | limited in particular, For example, it is the range of 10-200 micrometers, Preferably it is the range of 20-150 micrometers, Especially preferably, it is the range of 30-100 micrometers.

  The stretching method of the base material is not particularly limited. For example, when the base material is contracted later, the base material can be contracted in one direction. Therefore, the base material is stretched with one end fixed (fixed end stretching). Method stretching method). As described above, when the substrate is stretched, the direction opposite to the stretching direction is the shrinking direction. Therefore, if one end of the substrate is fixed and stretched in one direction, shrinkage occurs in one direction. This is because the non-liquid crystal polymer on the substrate can be tilted and oriented in one direction as will be described later.

  Next, a non-liquid crystal polymer is applied to the first base material in the same manner as described above to form a coating film, and the second base material is further laminated on the coating film, The coating film is sandwiched between the first base material and the second base material. At this time, the stretching direction of the first substrate and the stretching direction of the second substrate, that is, the shrinking direction of the first substrate and the stretching direction of the second substrate are aligned. Is preferred.

  The method for laminating the second base material on the coating film is not particularly limited, but for example, it may be simply laminated as it is. In this case, the second base material may be removed after the non-liquid crystalline polymer is tilted and oriented, or when the adhesiveness is high, it may be used as it is as an integrated product. Moreover, it is not limited to this, For example, you may adhere | attach the said 2nd base material with an adhesive agent or an adhesive agent on the said coating film.

  Subsequently, an external force is applied to the coating film due to the difference in shrinkage between the first base material and the second base material. Note that either one of the substrates may not shrink.

  Thus, when both the base materials (or one base material) are contracted, the two have different contraction ratios, so that a difference in contraction degree occurs between them, thereby forming the coating film. Are inclined. More specifically, for example, when the shrinkage rate of the first base material is larger than that of the second base material, the first base material side among the coating films according to the difference in shrinkage rate. Since this part contracts further than the part on the second substrate side, the non-liquid crystal polymer forming the coating film is tilted and oriented. For this reason, for example, the greater the difference in shrinkage between the two substrates, the greater the tilt angle of the polymer. Specifically, when the normal of the tilted optical compensation film is set to 0 °, the tilt angle of the non-liquid crystal polymer with respect to the normal is increased, and the polymer is tilted in the surface direction of the substrate.

  When both the base materials are contracted, it is preferable that the non-liquid crystal polymer on the base material is tilted and oriented in a certain direction as described above. For example, the first base material and the second base material It is preferable to fix both ends in the shrinkage direction of the material together.

  Examples of the method for shrinking the substrate include heat treatment. The conditions for the heat treatment are not particularly limited and can be appropriately determined depending on, for example, the type of non-liquid crystal polymer and the material of the base material. For example, the heating temperature is in the range of 25 to 300 ° C., preferably Is in the range of 50 to 200 ° C, particularly preferably in the range of 60 to 180 ° C.

  In this manner, the tilted optical compensation film made of the non-liquid crystal polymer that is tilt-aligned can be formed on the first substrate. In addition, the said 1st base material and a 2nd base material may peel either one, for example, and can also be used as an inclination optical compensation film, with both laminated | stacked.

  Further, similarly to the first manufacturing method, after the non-liquid crystal polymer is tilt-aligned, the non-liquid crystal polymer tilt-aligned may be further solidified on the first substrate. Solidification may be performed together with the inclined orientation by the heat treatment.

  The inventors found for the first time that the tilted optical compensation film of the present invention can be produced by the method as described above. However, the method for producing the tilted optical compensation film of the present invention is not limited thereto.

  The tilted optical compensation film formed on the substrate may be peeled off from the substrate or used as a laminate of the two.

  The tilted optical compensation film of the present invention thus produced has a birefringence layer (Δn) of 0.001 to 0.5 as described above. As other optical characteristics, for example, the thickness direction retardation (Rth) is preferably in the range of 20 to 1000 nm, more preferably 30 nm to 800 nm. The in-plane retardation (Δnd) is preferably in the range of 0 to 100 nm, more preferably 10 to 70 nm, and particularly preferably.

  In addition, the method for producing a tilted optical compensation film of the present invention may further include a stretching or shrinking step. When a tilted optical compensation film is formed using a liquid crystal material as in the past, the liquid crystal material is solidified after tilting and aligning the liquid crystal material. Processing such as stretching cannot be performed. For example, when a treatment such as stretching is performed, the tilted molecular structure is separated, and the tilted optical compensation film does not exhibit optical characteristics. Therefore, after the liquid crystal material is tilted, it is impossible to change the optical characteristics any more. However, when a non-liquid crystal polymer is used as a forming material as in the production method of the present invention, further stretching and the like are possible even after the non-liquid crystal polymer is solidified. For this reason, the phase difference in the in-plane direction and the thickness direction can be further changed. For example, the optical characteristics can be set according to the purpose of use. As described above, if the optical characteristics can be further modified, the use of the same tilted optical compensation film can be expanded and the cost can be reduced.

  Specifically, as a method of changing the optical characteristics, for example, a method of further stretching the base material and the tilted optical compensation film formed on the base material together can be mentioned. Thus, by extending | stretching the said inclination optical compensation film, the in-plane phase difference and thickness direction phase difference in the said inclination optical compensation film can be changed. The stretching treatment is not limited to these methods. For example, since the tilted optical compensation film is stretched along with stretching of the base material, only the base material may be stretched, or the base material may be stretched. It is also possible to peel and stretch only the tilted optical compensation film.

  In addition to the stretching method, for example, there is a method of using a shrinkable substrate as the substrate, forming a tilted optical compensation film on the substrate, and then shrinking the substrate. . As described above, after the tilted optical compensation film is formed, the base material is shrunk, so that the tilted optical compensation film is shrunk and the in-plane retardation can be changed.

As described above, after the non-liquid crystal polymer is tilted and oriented, the optical properties of the tilted optical compensation film are, for example, a thickness direction retardation (Rth) of, for example, 20 to 1000 nm. The in-plane retardation (Δnd) can be changed in the range of 5 to 200 nm. The degree of stretching or shrinkage may be changed according to, for example, desired optical characteristics, and can be performed by a known method. As described above, the tilted optical compensation film of the present invention is optically It is also possible to variously control the anisotropy of the refractive index. Accordingly, examples of the refractive index ellipsoid of the tilted optical compensation film of the present invention include a form as shown in FIG. 2 and may be a form in which these are hybrid-oriented. The figure is a diagram schematically showing the refractive index ellipsoid of the tilt alignment compensation film of the present invention,
(A) A refractive index ellipsoid of nx≈ny> nz is inclined,
(B) A refractive index ellipsoid of nx>ny> nz is inclined,
(C) Inclined refractive index ellipsoid of nx>nz> ny or nz>nx> ny,
(D) An index ellipsoid of nz> nx≈ny is inclined. In FIGS. 4A to 4D, the axis passing through the center of the ellipse is the “normal line of the tilted optical compensation film”, and the “normal line of the refractive index ellipsoid” is inclined in the direction of the arrow. ing.

  Next, the tilted optical compensation film of the present invention is useful as, for example, a retardation film or retardation plate for optical compensation.

  The tilted optical compensation film of the present invention is not particularly limited as long as it includes a birefringent layer in which the non-liquid crystal polymer is tilted and oriented as described above. It can be illustrated. For example, when the tilted optical compensation film of the present invention is formed on the base material (first base material) as described above, only the tilted birefringent layer peeled off from the first base material may be used. A laminate in which the birefringent layer is directly formed on the first substrate may be used. Moreover, the laminated body which peeled the said birefringent layer from the said 1st base material, and was laminated | stacked on the other 2nd base material may be sufficient, and the laminated body of the said 1st base material and the said birefringent layer May be a laminate produced by peeling only the first base material after adhering the second base material so that the birefringent layer faces the second base material.

  Among these forms, for example, the laminate of the first base material and the birefringent layer can be used as it is after the birefringent layer is directly formed on the base material. For example, when used in various image display devices such as liquid crystal display devices, a tilted optical compensation film can be provided at low cost, which is preferable.

  Next, the polarizing plate of the present invention is a laminated polarizing plate including an optical compensation film and a polarizer, wherein the optical compensation film is the tilted optical compensation film of the present invention.

  As long as such a laminated polarizing plate has the tilted optical compensation film of the present invention and the polarizer, the configuration thereof is not particularly limited, and examples thereof include the following configurations.

  For example, the first laminated polarizing plate has the tilted optical compensation film of the present invention, a polarizer and two transparent protective layers, and transparent protective layers are laminated on both sides of the polarizer, respectively, The inclined optical compensation film is further laminated on the surface of the protective layer. In addition, as for the said inclination optical compensation film, in the case of the laminated body of the said birefringent layer and a resinous base material as mentioned above, any surface may face the said transparent protective layer.

  Moreover, the said transparent protective layer may be laminated | stacked on both sides of the said polarizer, and may be laminated | stacked only on any one surface. 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.

  On the other hand, the second laminated polarizing plate has the tilted optical compensation film of the present invention, the polarizer 2 and a transparent protective layer, and the tilted optical compensation film is formed on one surface of the polarizer. The transparent protective layer is laminated on the other surface.

  When the tilted optical compensation film is a laminate of a birefringent layer and a resinous base material as described above, any surface may face the polarizer. For example, for the following reason It is preferable that the tilted optical compensation film is disposed so that the substrate side faces the polarizer. This is because, with such a configuration, the base material of the tilted optical compensation film can be used as a transparent protective layer in a laminated polarizing plate. That is, instead of laminating a transparent protective layer on both sides of the polarizer, a tilted optical compensation is made so that a transparent protective layer is laminated on one side of the polarizer and the substrate faces the other side. By laminating films, the substrate also serves as a transparent protective layer. For this reason, the polarizing plate made still thinner can be obtained.

  When the tilted optical compensation film is a laminate of a birefringent layer and a resinous substrate as described above, a polarizer may be used as the resinous substrate. When the resin base material also serves as a polarizer, a further thinned polarizing plate can be obtained.

  The polarizer (polarizing film) is not particularly limited. For example, by a conventionally known method, various films such as iodine and dichroic dyes are adsorbed and dyed, crosslinked, stretched, Those prepared by drying 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 protective film can be used. For example, a layer having excellent transparency, mechanical strength, thermal stability, moisture barrier property, isotropy and the like is preferable. Specific examples of such transparent protective layer materials include cellulose resins such as triacetyl cellulose (TAC), polyester resins, polycarbonate resins, polyamide resins, polyimide resins, polyethersulfone resins, polysulfone resins, and polystyrene resins. And transparent resins such as polynorbornene, polyolefin, polyacryl, and polyacetate. 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, the alignment film of the liquid crystal polymer is preferable because it can achieve a wide viewing angle with good visual recognition, and in particular, the optical compensation layer composed of the inclined alignment layer of a 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 according to, for example, the phase difference or the protective strength, but is usually 500 μm or less, preferably 5 to 300 μm, more preferably 5 to 150 μm. It 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 for laminating the components (gradient optical compensation film, polarizer, transparent protective layer, etc.) is not particularly limited, and can be performed by a conventionally known method. In general, the same pressure-sensitive adhesives and adhesives as described above can be used, and the type thereof can be appropriately determined depending on the material of each 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. 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.

  Moreover, the polarizing plate of this invention can also be manufactured by the following methods, for example. For example, when the laminated body is prepared by forming the birefringent layer on the base material by the method for producing a tilted optical compensation film of the present invention, a polarizer or a polarizing plate is formed via the adhesive layer or the like. A method in which the birefringent layer of the laminate is bonded to the transparent protective layer, or the birefringent layer of the laminate is transferred to the polarizer or the transparent protective layer after being transferred. There is a method of peeling only the substrate. In addition, a birefringent layer is formed on one surface of the base material (first base material) by the method for manufacturing a tilted optical compensation film of the present invention, and the first base material is used as a transparent protective layer of a polarizing plate. As another example, there is a method of attaching a polarizer to the other surface side of the first base material via the adhesive or the like. Thus, if the polarizing plate of the present invention is manufactured using the manufacturing method of the tilted optical compensation film of the present invention, for example, the polarizing plate can be provided at a low cost with a small number of steps. Since the thickness is reduced, the polarizing plate itself including this can also be reduced in thickness.

  Furthermore, the tilted optical compensation film of the present invention may be used in combination with conventionally known optical members such as various retardation plates, diffusion control films, brightness enhancement films, etc. in addition to the polarizer as described above. it can. 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. The tilted optical compensation film can also be combined with, for example, a wire grid polarizer.

  In practical use, the laminated polarizing plate of the present invention may further contain other optical layers in addition to the tilted optical compensation film 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 including the birefringent layer. 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 of the present invention 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 polarizing plates of the present invention may be, for example, an optical member including two or more optical layers by laminating a laminated polarizing plate including a birefringent layer as described above and an optical layer.

  An optical member in which two or more optical layers are laminated in this way 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 for the adhesive layer is not particularly limited, and a conventionally known material such as an acrylic polymer can be used. For example, it is preferable to form a pressure-sensitive adhesive layer having a low moisture absorption rate and excellent heat resistance, from the viewpoint 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. Or a method of forming a pressure-sensitive adhesive layer on a separator, which will be described later, and transferring it 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, the surface can be covered with a liner (separator) for the purpose of preventing contamination until the pressure-sensitive adhesive layer is put to practical use. preferable. This liner can be formed on a suitable film such as the above-mentioned transparent protective film by a method of providing a release coat with a release agent such as silicone, long chain alkyl, fluorine, or 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 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 tilted optical compensation film and polarizing plate of the present invention as described above, a polarizing film forming various optical members (various polarizing plates further laminated with an optical layer), a transparent protective layer, an optical layer, an adhesive layer, For example, it may have an 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 tilted optical compensation film and polarizing plate of the present invention are preferably used for forming various devices such as a liquid crystal display device. For example, a polarizing plate is disposed on one side or both sides of a liquid crystal cell. It can be used for a liquid crystal display device such as a reflective type, a transflective type, or a transmissive / reflective type.

  The type of the liquid crystal cell forming the liquid crystal display device is, for example, an active matrix driving type typified by a thin film transistor (TFT) type, a simple type typified by a TN (twisted nematic) type or STN (super twisted nematic) type. Various types of liquid crystal cells such as a matrix driving type can be used. Among these, it is preferable to use for a liquid crystal cell whose display method is a TN type, STN type, or OCB (Optically Aligned Birefringence) type. Further, even in the case of a VA (Vertical Aligned) type or the like, it can be applied to such a liquid crystal cell when the alignment of the liquid crystal is a monodomain alignment.

  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 the optical compensation layer of this invention, a polarizing plate, and another optical member in both surfaces of a liquid crystal cell, they may be the same kind and may differ. 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. Further, the light source may further include a light source. The light source is not particularly limited, but is preferably a flat light source that emits polarized light, for example, because light energy can be used effectively.

  Examples of the liquid crystal panel of the present invention include the following forms. The liquid crystal panel has, for example, a liquid crystal cell, the tilted optical compensation film of the present invention, a polarizer 2 and a transparent protective layer, and the tilted optical compensation film is laminated on one surface of the liquid crystal cell, The polarizer and the transparent protective layer are laminated in this order on the other surface of the tilted optical compensation film. The liquid crystal cell has a configuration in which liquid crystal is held between two liquid crystal cell substrates. In addition, when the tilted optical compensation film is a laminate of a birefringent layer and a substrate as described above, the arrangement thereof is not particularly limited. For example, the birefringent layer side faces the liquid crystal cell. The base material side faces 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 disposed on the tilted optical compensation film on the viewing side, or the liquid crystal cell in the liquid crystal panel A compensation retardation plate or the like can be appropriately disposed between the polarizing plate and the polarizing plate.

  The tilted optical compensation film and polarizing plate of the present invention are not limited to the liquid crystal display device as described above, and examples thereof include an organic electroluminescence (EL) display, PDP, plasma display (PD), and FED (field emission display). : Field Emission Display) and the like. When used in a self-luminous flat display, for example, by setting the polarizing plate of the present invention to Δnd = λ / 4, circularly polarized light can be obtained, so that it can be used as an antireflection filter.

  Hereinafter, an electroluminescence (EL) display device including the tilted optical compensation film and the polarizing plate of the present invention will be described. The EL display device of the present invention is a display device having the tilted optical compensation film or polarizing plate of the present invention, and this EL device 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. In particular, the tilted optical compensation film and polarizing plate of the present invention may emit linearly polarized light, circularly polarized light or elliptically polarized light from the EL layer, or emit natural light in the front direction. 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. The tilted optical compensation film or polarizing plate of the present invention is preferably disposed on the surface of the transparent electrode, and a λ / 4 plate is preferably disposed between the polarizing plate and the EL element. Thus, by arranging the tilted optical compensation film and the 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.

  For example, the retardation film and the optical film (polarizing plate, etc.) have a function of polarizing the light incident from the outside and reflected by the metal electrode, so that the mirror surface of the metal electrode is visually recognized from the outside by the polarization action. There is an effect of not letting it. 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 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 in more detail using an Example and a comparative example, this invention is not limited to a following example.

Example 1
2,2′-bis (trifluoromethyl) -4,4 ′, 5,5′-biphenyltetracarboxylic dianhydride and 2,2′-bis (trifluoromethyl) -4,4′-diaminobiphenyl A polyimide having a weight average molecular weight (Mw) of 70,000 synthesized from the above was dissolved in cyclohexanone to prepare a 10 wt% polyimide solution. And the said polyimide solution was applied to the surface of 75-micrometer-thick PET film (Toray Industries, Inc. brand name S27). And the hot air was applied to this coating film from the air blower, and the polyimide of the said coating film was inclined. The conditions of this treatment were a wind speed of 20 m / sec, a wind temperature of 100 ° C., a time of 5 minutes, a distance of 30 cm between the coating film surface and the blower tip, and the laminate of the PET film and the coating film was placed on the belt The hot air was applied by placing and continuously delivering at a speed of 2 m / min. And the polyimide film with a thickness of 4 micrometers was formed on the said PET film by heat-drying for 5 minutes at 150 degreeC, and fixing the polyimide which carried out the inclination orientation on the said PET film. When the birefringence of the polyimide film was evaluated, it was found to be a birefringent layer having a birefringence (Δn) of about 0.041.

  The said polyimide film was peeled from the said PET film, and the phase difference in 590 nm was measured about this polyimide film using the phase difference meter (brand name KOBRA-21ADH: Oji Scientific Instruments company make). In this phase difference measurement, the normal line of the polyimide film is set to 0 °, and the normal line (0 °) and the axis inclined from −50 ° to + 50 ° in the fast axis direction of the polyimide film from the normal line are measured. The measurement was performed from the measurement axis direction as the axis. These results are shown in FIG. This figure is a graph showing the relationship between the measurement angle (tilt angle) and the phase difference value at each measurement angle, where the horizontal axis indicates the angle and the vertical axis indicates the phase difference value.

  As shown in the figure, the curve of the phase difference value at the measurement angle (−50 to + 50 °) when the normal is 0 ° is on the vertical axis (dotted line in the same figure) passing through 0 ° (normal). On the other hand, since it was asymmetric, it was confirmed that the film was a tilted optical compensation film in which the polyimide was tilted. Further, the minimum phase difference value is shown in the vicinity of an inclination of about + 10 ° in the fast axis direction from the normal line.

  Furthermore, this polyimide film was laminated on a commercially available polarizing plate (trade name HEG1425DU: manufactured by Nitto Denko Corporation). This laminated polarizing plate was further mounted on a liquid crystal panel of a commercially available TN mode liquid crystal display device so that the polyimide film and the liquid crystal panel face each other. And the contrast of this liquid crystal display device was calculated | required. The contrast is obtained by displaying a white image and a black image on the liquid crystal display device, and by using the product name Ez contrast 160D (manufactured by ELDIM Co., Ltd.) Y value, x value, and y value were measured. Then, the contrast “Yw / YB” at each viewing angle was calculated from the Y value (Yw) in the white image and the Y value (YB) in the black image. On the other hand, as a comparative example, the contrast at the viewing angle was also confirmed for a liquid crystal display device in which only the commercially available polarizing plate was mounted instead of the laminated polarizing plate.

  As a result, according to the liquid crystal display device on which the laminated polarizing plate of the example was mounted, the viewing angle showing a contrast of 10 or more compared to the liquid crystal display device of the comparative example in which only the commercially available polarizing plate was mounted was that of the comparative example. It was expanded to the range of + 15 ° to the left and right of the viewing angle.

(Control 1)
A 1% by weight aqueous solution of polyvinyl alcohol (trade name NH-18, manufactured by Nippon Synthetic Chemical Co., Ltd.) was applied to the surface of the glass plate with a spin coater and dried at 120 ° C. for 5 minutes. As a result, a PVA film having a film thickness of 0.5 μm was formed on the glass plate. Further, the surface of the PVA film was rubbed five times in one direction with a commercially available rubbing cloth to form an alignment film. Then, on the surface of the alignment film, a 10% by weight tetrachloroethylene solution of a triphenylene discotic liquid crystal represented by the following formula is applied by a spin coater, and the applied film is heat-treated at 200 ° C. for 5 minutes. The liquid crystal material was aligned. By this heat treatment, an inclined birefringent layer having a thickness of 2 μm and a birefringence (Δn) of about 0.040 was formed on the alignment film.

  For the inclined birefringent layer of Comparative Example 1, the phase difference was measured in the same manner as in Example 1. The result is shown in FIG. 3 is a graph showing the relationship between the angle of the normal line-measurement axis and the phase difference value in each measurement axis, as in FIG. 3, wherein the horizontal axis indicates the angle and the vertical axis indicates the phase difference value. As shown in FIG. 4, the curve of the phase difference value at the measurement angle (-50 to + 50 °) when the normal is 0 ° is the vertical axis passing through 0 ° (normal) (dotted line in the figure). The minimum phase difference value was asymmetrical with respect to the normal line in the vicinity of the inclination of about + 30 ° in the fast axis direction.

  Furthermore, as a result of mounting this birefringent layer on a commercially available TN mode liquid crystal display device in the same manner as in Example 1, there was a region showing a contrast of 10 or more compared to the case where only the commercially available polarizing plate was mounted. It was confirmed that the image was enlarged by + 15 ° in the left-right direction.

  As can be seen from the above results, the gradient optical compensation film of the example is slightly asymmetric with respect to the vertical axis, although there is a slight difference in the shape of the phase difference and measurement angle graphs compared to the control example. there were.

  In addition, as a result of further stretching the tilted optical compensation films produced in the examples and the control examples, the tilted optical compensation films of the control examples were not practical as tilted optical films because the tilted alignment of liquid crystal molecules was dispersed. In contrast, the tilted optical compensation layer of the example could further change the in-plane retardation. Also from this fact, it can be said that the tilted optical compensation film of the present invention is useful because the optical characteristics can be further changed according to the use, and the use is expanded.

It is a graph which shows the relationship between the measurement angle of a phase difference, and a phase difference value in the inclination optical compensation film of this invention. It is the schematic which shows the form of the refractive index ellipsoid in the inclination optical compensation film of this invention. In one Example of this invention, it is a graph which shows the relationship between the phase difference value of a tilting optical compensation film, and a measurement angle. It is a graph which shows the relationship between the retardation value of a tilting optical compensation film, and a measurement angle in a control example.

Claims (12)

An optical compensation film comprising a non-liquid crystal polymer,
The non-liquid crystal polymer is tilted;
When the normal of the optical compensation film surface is 0 ° and the angle between the normal and the measurement axis is a measurement angle (including 0 °),
The phase difference value measured from the measurement axis direction is centered on the phase difference value at 0 °, and the change in the phase difference value is asymmetric between the + side and the − side,
The thickness of the optical compensation film is 0.5 to 50 μm,
And,
An optical compensation film having a birefringence (Δn) represented by the following formula in a range of 0.001 to 0.5.
Δn = [[(nx + ny) / 2] −nz] · d / d
In the above formula, Δn represents the birefringence of the tilted optical compensation film, nx, ny and nz represent the refractive indexes in the X-axis, Y-axis and Z-axis directions of the tilted optical compensation film, respectively, and the X-axis Is the axial direction showing the maximum refractive index in the plane of the tilted optical compensation film, the Y axis is the axial direction perpendicular to the X axis in the plane, and the Z axis is the X direction The thickness direction perpendicular to the axis and the Y axis is shown, and d denotes the thickness of the tilted optical compensation film.   2. The tilted optical compensation film according to claim 1, wherein the non-liquid crystal polymer is at least one polymer selected from the group consisting of polyamide, polyimide, polyester, polyetherketone, polyamideimide, and polyesterimide. An optical compensation film comprising a non-liquid crystal polymer,
The non-liquid crystal polymer is tilted;
When the normal of the optical compensation film surface is 0 ° and the angle between the normal and the measurement axis is a measurement angle (including 0 °),
The phase difference value measured from the measurement axis direction is centered on the phase difference value at 0 °, and the change in the phase difference value is asymmetric between the + side and the − side,
The thickness of the optical compensation film is 0.5 to 50 μm,
And,
The optical compensation film, wherein the non-liquid crystal polymer is at least one polymer selected from the group consisting of polyamide, polyimide, polyester, polyetherketone, polyamideimide, and polyesterimide. The tilted optical compensation film according to claim 3, wherein the birefringence (Δn) represented by the following formula is in the range of 0.001 to 0.5.
Δn = [[(nx + ny) / 2] −nz] · d / d
In the above formula, Δn represents the birefringence of the tilted optical compensation film, nx, ny and nz represent the refractive indexes in the X-axis, Y-axis and Z-axis directions of the tilted optical compensation film, respectively, and the X-axis Is the axial direction showing the maximum refractive index in the plane of the tilted optical compensation film, the Y axis is the axial direction perpendicular to the X axis in the plane, and the Z axis is the X direction The thickness direction perpendicular to the axis and the Y axis is shown, and d denotes the thickness of the tilted optical compensation film.   The tilted optical compensation film according to any one of claims 1 to 4, wherein the maximum value or the minimum value of the retardation values is a retardation value on the + side or-side of the measurement angle.   The tilted optical compensation film according to any one of claims 1 to 5, wherein the measurement angle is -50 to + 50 °.   The inclined optical compensation film according to claim 6, wherein the maximum value or the minimum value of the retardation value is a retardation value at the measurement angle of −2 ° to −50 ° or + 2 ° to + 50 °.   The measurement axis includes a normal line and an axis inclined from the normal line, and the axis inclined from the normal line is inclined in the slow axis direction of the inclined optical compensation film. The tilted optical compensation film according to Item.   The measurement axis includes a normal line and an axis inclined from the normal line, and the axis inclined from the normal line is inclined in the fast axis direction of the inclined optical compensation film. The tilted optical compensation film according to Item.   The tilt optical compensation film according to any one of claims 1 to 9, which is used for a liquid crystal display device in which a display method is a TN (Twisted Nematic) mode or an OCB (Optically Aligned Birefringence) mode.   The tilted optical compensation film according to any one of claims 1 to 10, which is used for a liquid crystal display device in which liquid crystal alignment is monodomain alignment.   The tilted optical compensation film according to claim 10, wherein a region showing a contrast of 10 or more in a liquid crystal display device in which a display method is a TN mode is expanded by 10 ° or more in a horizontal direction of the display surface.

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