JP2005292727A - Laminated phase difference film, its manufacturing method and optical film using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a laminated phase difference film where an inclined oriented birefringent layer whose inclined orientation direction is controlled is laminated on a negative biaxial birefringent film without arranging an oriented film additionally. <P>SOLUTION: The birefringent oriented film is manufactured by irradiating the surface of the biaxial birefringent film with polarized light and changing only the surface of the film so as to have anisotropy different from the inside. If the liquid crystal layer of a bar-shaped liquid crystalline compound is directly formed on the surface of the birefringent oriented film irradiated with polarized light, the inclined oriented birefringent layer inclined according to the anisotropy of the surface of the birefringent oriented film is laminated, whereby the laminated phase difference film is provided. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a laminated retardation film useful for optical compensation of various image display devices, a production method thereof, and an optical film using the same.

  Conventionally, various liquid crystal display devices have various viewing angle characteristics problems such as a decrease in contrast ratio and occurrence of gradation inversion in the black display portion when viewed from an oblique direction. A refractive film (retardation film) is used as an optical compensation film.

  In recent years, with respect to optical compensation films using liquid crystalline compounds, development of films formed from liquid crystalline compounds has been made as optical compensation films that optimize optical characteristics according to the operation mode of a liquid crystal display (LCD). It is actively done.

  Among them, as a film for compensating a twisted nematic (TN) mode LCD, a so-called inclined alignment film in which the optical axis is inclined with respect to the film plane is important. As such a tilted alignment film, conventionally, a tilted discotic liquid crystal or a tilted rod-like nematic liquid crystal polymer is known. In addition, it has been reported that a laminated film obtained by laminating a uniaxially oriented retardation film and a tilted oriented film is suitable for the TN mode (see Non-Patent Document 1).

On the other hand, optically biaxial retardation films are generally used for liquid crystal modes in which almost all liquid crystals in the cell are homeotropically aligned, such as a VA (Vertically Aligned) mode and an OCB (Optical Compensated Birefringence) mode.
1999 SID digest “Wide-Viewing-Angle Photoaligned Plastic Film for TN-LCPs”, 1999, pp. 98-101

  At present, there is a demand for an optical compensation film that can perform optical compensation more strictly for various liquid crystal modes, particularly for the VA mode and the OCB mode. Therefore, for example, in a liquid crystal cell such as VA mode and OCB mode, the biaxial retardation film and the tilted alignment film are used for the purpose of compensating for tilted alignment molecules (liquid crystal) in the vicinity of the alignment film in the cell. A combination is being tried. However, in order to design the optical characteristics, for example, when adjusting the slow axis directions of the biaxial retardation film and the inclined alignment film to a predetermined angle, there are the following problems. That is, the direction of the tilt alignment of the liquid crystal compound constituting the tilt alignment film is determined according to, for example, the anisotropy (orientation) of the substrate. For this reason, in order to appropriately set the slow axis of the biaxial retardation film and the tilted orientation film, it is necessary to separately prepare the biaxial retardation film and the tilted orientation film and bond them using an adhesive or the like. . In addition, when forming an inclined alignment film on a biaxial retardation film, it is essential to dispose an alignment film on the biaxial retardation film so that the liquid crystalline compound is aligned in a desired direction. It is. As described above, since the intervention of the adhesive and the alignment film is an essential requirement, the film thickness is increased, and it is difficult to meet the recent demand for thinner image display devices. In addition, there is a problem that it takes time to adjust the bonding between the biaxial retardation film and the alignment film, and the biaxial retardation film and the tilted alignment film.

  Accordingly, an object of the present invention is to provide a laminated retardation film useful for setting desired optical characteristics, and more specifically, for example, biaxial birefringence without separately arranging an alignment film. The present invention provides a laminated retardation film obtained by directly laminating a conductive film and a tilt-oriented birefringent layer tilt-oriented in a desired direction, and a method for producing the same.

  In order to achieve the above object, the method for producing a laminated retardation film of the present invention irradiates at least one surface of a birefringent polymer film exhibiting optical properties represented by the following formula (I) with polarized light, A step of producing a birefringent alignment film by changing the anisotropy of only the surface irradiated with polarized light of the polymer film, and a coating containing a rod-like liquid crystalline compound on the polarized irradiation surface of the birefringent alignment film. The coating liquid is directly applied to form a coating film, and the coating film is subjected to heat treatment to align the rod-like liquid crystalline compound according to the anisotropy of the alignment film, thereby forming a tilted alignment birefringent layer. Forming.

    nx '> ny'> nz '(I)

  In the formula (I), nx ′, ny ′, and nz ′ represent refractive indexes in the X-axis, Y-axis, and Z-axis directions of the polymer film, respectively, and the X-axis direction is the surface of the polymer film. In which the Y axis is an axial direction perpendicular to the X axis in the plane, and the Z axis is a thickness direction perpendicular to the X axis and the Y axis. Show. The optical characteristic represented by the formula (I) is referred to as optically negative biaxiality.

  Further, the laminated retardation film of the present invention is a laminated retardation film comprising an alignment film having birefringence containing a non-liquid crystalline polymer and an inclined alignment birefringent layer in which rod-like liquid crystalline compounds are inclined and aligned. The birefringent oriented film exhibits optical characteristics represented by the following formula (II), at least one surface of the birefringent oriented film exhibits anisotropy different from the inside thereof, and the birefringent property The tilted alignment birefringent layer is directly laminated on the surface of the alignment film having anisotropy different from the inside, and in the tilted alignment birefringent layer, the rod-like liquid crystalline compound is formed of the birefringent alignment film. Inclined orientation according to the anisotropy of the surface is characterized.

    nx> ny> nz (II)

  In the formula (II), nx, ny, and nz respectively indicate refractive indexes in the X-axis, Y-axis, and Z-axis directions of the oriented film, and the X-axis direction is the maximum in the plane of the oriented film. The Y-axis is an axial direction perpendicular to the X-axis in the plane, and the Z-axis is a thickness direction perpendicular to the X-axis and the Y-axis.

  As a result of diligent research, the present inventors changed the surface to anisotropy different from the inside of the film by irradiating the surface of the biaxial birefringent polymer film with polarized light, It has been found that on the surface, the rod-like liquid crystalline compound is tilted and aligned according to the anisotropy of the surface, not the inside of the film. And based on this, it came to the manufacturing method of the lamination | stacking phase difference film of this invention. The laminated retardation film of the present invention obtained by such a manufacturing method does not require a separate alignment film in order to control the tilt direction of the tilted alignment birefringent layer, for example, and can be thinned. , Variation in optical properties will also spread. Therefore, it can be said that it is extremely useful for various image display devices including a liquid crystal display device.

  As described above, the method for producing a laminated retardation film of the present invention irradiates at least one surface of a birefringent polymer film exhibiting optical properties represented by the following formula (I) with polarized light, and the polymer film A step of producing a birefringent alignment film by changing its anisotropy only on the surface irradiated with the polarized light, and a coating liquid containing a rod-like liquid crystalline compound on the polarized irradiation surface of the birefringent alignment film. Directly coating to form a coating film, heating the coating film, and orienting the rod-like liquid crystalline compound according to the anisotropy of the orientation film to form a tilted orientation birefringent layer Including.

  Although an example of the manufacturing method of the present invention will be described below, the present invention is not limited to this example.

  First, one surface of the birefringent polymer film is irradiated with polarized light. Thereby, the anisotropy is changed only on the surface of the birefringent polymer film, and a birefringent alignment film having anisotropy different from the inside of the polymer film can be formed. That is, it can be said that the slow axis direction of the surface has changed in a direction different from the internal slow axis due to the irradiation of polarized light. The slow axis direction and the fast axis direction in the entire birefringent alignment film after polarized light irradiation are the same directions as the slow axis and fast axis directions of the birefringent polymer film before polarized light irradiation, The optical characteristics as a whole also show the negative optical biaxiality represented by the formula (I), like the birefringent polymer film.

  The reason why the anisotropy of the surface can be changed by irradiation with polarized light is not clear, but it is considered that the polymer constituting the birefringent polymer film is decomposed by irradiation with polarized light (for example, Liquid Crystals 26, 575-580). (1999)). If it demonstrates concretely, the component (polymer) of the said polymer film in the polarization direction will selectively be decomposed | disassembled by the polarized light irradiation to the said polymer film surface. For this reason, the refractive index of the polarization direction becomes relatively small on the surface of the polymer film. That is, the refractive index in the polarization direction is relatively small only on the surface of the polymer film, while the refractive index in the 90 ° direction is relatively large with respect to the polarization direction. It becomes a state where the directionality is different from the internal anisotropy, that is, a state where the anisotropy is different. Since the surface anisotropy is different from the inside as described above, the rod-like liquid crystalline compound described later is aligned according to the surface anisotropy of the birefringent alignment film (that is, the slow axis direction on the surface). . Specifically, for example, when polarized irradiation is performed in the same direction as the slow axis direction (for example, the stretching direction) of the birefringent polymer film, the surface of the obtained birefringent oriented film is in the irradiation direction. The maximum refractive index appears in the 90 ° direction. Therefore, the rod-like liquid crystalline compound described later is tilted and oriented in the direction of 90 ° (the direction showing the maximum refractive index) with respect to the slow axis inside the birefringent oriented film.

  The polarized light is, for example, ultraviolet polarized light, preferably 200 to 400 nm ultraviolet polarized light. Further, linearly polarized light and elliptically polarized light are preferable, and ultraviolet linearly polarized light is particularly preferable.

  Although the irradiation angle of polarized light is not particularly limited, for example, 0 to 80 ° is preferable, more preferably 10 to 60 °, and particularly preferably 20 to 45 °.

  The polarization direction at the time of irradiation can be appropriately determined according to the direction in which the rod-like liquid crystal compound is inclined. For example, when it is desired to incline in the direction of 90 ° with respect to the slow axis of the birefringent polymer film, the polarization direction may be set in the same direction as the slow axis of the polymer film. When it is desired to incline in the direction of 45 ° with respect to the slow axis, the polarization direction may be set in the direction of 45 ° with respect to the slow axis of the polymer film. Among them, the birefringent polymer film is preferably irradiated with polarized light in the same direction as the slow axis, and the angle between the slow axis and the polarized axis to be irradiated is, for example, 0 ± 5 °, The angle is preferably 0 ± 2 °.

  Next, a coating liquid containing a rod-like liquid crystalline compound is directly applied to the polarized irradiation surface of the birefringent oriented film, that is, the surface exhibiting anisotropy different from the inside to form a coating film. Then, the coating film is subjected to a heat treatment to orient the rod-like liquid crystalline compound according to the anisotropy of the orientation film, thereby forming a tilted orientation birefringent layer.

  In addition to the rod-like liquid crystalline compound, the coating liquid may contain, for example, the above-described solvent, additive, crosslinking agent, polymerization agent, and the like. The content of the liquid crystal compound in the coating liquid is, for example, 10 to 50 parts by weight, preferably 20 to 30 parts by weight, with respect to 100 parts by weight of the solvent. Can be used. Moreover, the coating method of the said coating liquid can be performed by a conventionally well-known method similarly to the above-mentioned.

  Such a rod-like liquid crystalline compound can be oriented according to the orientation direction of the oriented film by transitioning to a liquid crystal phase. That is, since the liquid crystalline compound exhibits a liquid crystal phase in a specific temperature range depending on, for example, the liquid crystal phase appears when the coating film is processed in the predetermined temperature range, and the rod-shaped liquid crystal The functional compound can be oriented. At this time, the rod-like liquid crystalline compound is oriented according to the anisotropy of the surface irradiated with polarized light, not the internal anisotropy of the oriented film, specifically, the direction perpendicular to the irradiation direction of polarized light on the surface. Inclined orientation.

  The conditions for the heat treatment can be determined according to the type of rod-like liquid crystalline compound used as described above. In order to fix the alignment state of the rod-like liquid crystalline compound, a rapid cooling treatment may be performed after the heat treatment.

  The rod-like liquid crystal compound may be a monomer liquid crystal compound or a polymer liquid crystal compound. When the rod-like liquid crystalline compound is a monomer liquid crystalline compound, it is preferably a polymerizable monomer liquid crystalline compound for the reasons described later.

  As the rod-like liquid crystalline compound as described above, a conventionally known compound can be used, and examples thereof include a commercially available product name UCL-001 (manufactured by Dainippon Ink & Chemicals, Inc.).

  When the rod-like liquid crystal compound is a polymerizable monomer, the alignment state may be fixed by polymerizing the monomer by, for example, photopolymerization or thermal polymerization. When the rod-like liquid crystalline compound is polymerized in this manner, the monomer compound used itself is liquid crystalline, but the polymer formed by the polymerization fixation becomes non-liquid crystalline. For this reason, the formed tilted alignment birefringent layer has a tilted alignment structure such as a liquid crystal phase, but due to polymerization, a change to a liquid crystal phase, a glass phase, or a crystal phase due to a temperature change peculiar to a liquid crystal monomer. It does not happen. Therefore, the layer has an extremely stable structure in which the orientation structure is not affected by temperature change.

  Thus, if the birefringent polymer film is irradiated with polarized light and the anisotropy of the surface is changed, the polymer film is oriented according to the anisotropy of the polarized irradiation surface instead of the anisotropy inside the polymer film. A tilted birefringent layer can be formed directly on the surface of the birefringent polymer film. For this reason, the laminated position of the present invention in which an inclined oriented birefringent layer oriented in a desired direction is directly laminated on the birefringent polymer film without separately arranging an oriented film on the birefringent polymer film as in the prior art. A phase difference film is obtained. In the laminated retardation film of the present invention, since the oriented film showing birefringence and the tilted oriented birefringent layer are directly laminated, the thickness becomes extremely thin, and further, the variation of optical characteristics that can be set is extremely widened. Therefore, it can be said that this is a very useful production method in the optical field.

  The birefringent polymer film subjected to the polarization treatment exhibits the optical characteristics (negative biaxiality) represented by the formula (I), and the orientation direction of the surface is changed by the polarization irradiation described above. Although it will not restrict | limit especially if it can change, For example, it is preferable that it is a film containing a non-liquid crystalline polymer.

  Examples of the non-liquid crystal polymer include polyamide, polyimide, polyester, polyetherketone, polyaryletherketone, and polyamideimide as described above because of excellent heat resistance, chemical resistance, transparency, and high rigidity. Polymers such as polyesterimide 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. . The molecular weight of such a non-liquid crystalline polymer is not particularly limited, but can be determined according to the viscosity and concentration since the viscosity can be adjusted by the molecular weight and concentration of the non-liquid crystalline polymer. Specifically, the weight average molecular weight (Mw) is preferably in the range of 1,000 to 1,000,000, more preferably in the range of 10,000 to 400,000. Among the polymers listed above, polyimide is particularly preferable because of its high transparency, high orientation, and high stretchability.

  With such a non-liquid crystalline polymer, when preparing the birefringent polymer film, for example, negative biaxiality can be realized as shown below regardless of whether or not the substrate is oriented. Because.

  The method for preparing the polymer film is not particularly limited. However, when the non-liquid crystalline polymer is, for example, polyimide as described above, a coating liquid containing the non-liquid crystalline polymer is applied to the surface of the substrate. A stretched film or a contracted film obtained by forming a work film and further stretching or shrinking the film can be used.

  If it is the said non-liquid crystalline polymer, plane orientation will arise in the said coating film regardless of the presence or absence of the orientation of the said base material. That is, the coating film, for example, contracts in the film thickness direction by drying and exhibits a phenomenon in which the orientation is expressed in the molecular orientation, and thus exhibits negative uniaxial (nx> nz, ny> nz) optical characteristics. It is. And if this coated film is stretched or shrunk, a difference will occur in the in-plane refractive index (nx, ny), so that the stretched film or shrunk film obtained is a negative two shown in the above formula (I). It shows axiality. In addition, the polymer film formed in this way may be peeled off from the base material and used as a laminate with the base material, for example.

  The polymer may be coated on the base material by, for example, a heat melting method. For example, the non-liquid crystalline polymer is dissolved or dispersed in a solvent from the viewpoint of production efficiency and optical orientation control. A method of applying a polymer solution is preferred. For the coating treatment, for example, a conventionally known method such as a spin coating method, a roll coating method, a flow coating method, a printing method, a dip coating method, a casting film forming method, a bar coating method, or a gravure printing method is appropriately employed. it can.

  The solvent is not particularly limited, and for example, methylene chloride, cyclohexanone, trichloroethylene, tetrachloroethane, N-methylpyrrolidone, tetrahydrofuran and the like can be used as appropriate. From the viewpoint of viscosity, for example, the polymer liquid is preferably mixed with 5 to 50 parts by weight, more preferably 10 to 40 parts by weight with respect to 100 parts by weight of the solvent. Moreover, the polymer liquid may further contain various additives such as a stabilizer, a plasticizer, and metals as necessary.

  After applying the coating liquid to the substrate, for example, natural drying or heat drying treatment may be performed. By such drying treatment, the polymer is fixed on the substrate, and the birefringence is obtained. Can be formed. As for the conditions of the said heat drying process, about 40-200 degreeC is preferable, for example.

  Although the thickness of this coating film is not specifically limited, For example, it is 0.1-100 micrometers, for example, Preferably it is 0.5-50 micrometers, More preferably, it is 2-10 micrometers. The birefringence (Δn) represented by the following formula of the coated film is 0.01 or more, more preferably 0.02 to 0.2, and particularly preferably 0.03 to 0.0. 1.

      Δn = nx ″ −nz ″

  In the above formula, nx ″ and nz ″ indicate the refractive indexes in the X-axis and Z-axis directions of the film, respectively, and the X-axis direction is the axial direction indicating the maximum refractive index in the plane of the film. And the Z-axis indicates the thickness direction perpendicular to the X-axis.

  For the stretching treatment, various methods such as free end uniaxial stretching, fixed end uniaxial stretching, sequential uniaxial stretching, sequential biaxial stretching, simultaneous biaxial stretching, and oblique stretching can be employed. In addition, the orientation nucleus can be controlled by using an oblique stretching technique. The degree of stretching is not particularly limited and can be determined according to desired optical properties. The thickness of the coating film (namely, polymer film) after the stretching treatment is, for example, 0.05 to 100 μm, preferably 0.25 to 50 μm, and more preferably 1 to 10 μm.

  In the case of shrinkage treatment, for example, the method of changing the dimensions of the substrate and shrinking the coating film along with this, the method of imparting shrinkage to the substrate in advance, and the like, for example, It is also possible to control the shrinkage rate using a stretching machine or the like.

  Next, as described above, the laminated retardation film of the present invention is a laminate comprising a birefringent orientation film containing a non-liquid crystalline polymer and a tilted orientation birefringent layer in which a rod-like liquid crystalline compound is tilted. A retardation film, wherein the birefringent oriented film exhibits optical properties represented by the following formula (II), and at least one surface of the birefringent oriented film has anisotropy different from the inside thereof. The tilted orientation birefringence layer is laminated directly on the surface (hereinafter also referred to as “modified surface”) showing anisotropy different from the inside of the birefringent oriented film, In the layer, the rod-like liquid crystalline compound is tilted and oriented according to the anisotropy of the surface of the birefringent oriented film. Such a laminated retardation film can be produced by the production method of the present invention as described above, but is not limited thereto.

  In the birefringent oriented film, “one surface showing an orientation direction different from the inside” does not indicate only an exposed surface in contact with the outside world, and “an orientation direction different from the inside of the oriented film”. Means a region including the exposed surface.

  In the birefringent oriented film, the angle between the orientation direction of the modified surface and the internal orientation direction is, for example, preferably 90 ° ± 5 °, more preferably 90 ± 2 °.

  The birefringent oriented film and the tilted oriented birefringent layer are directly laminated so that, for example, the angle between the slow axis of the oriented film and the slow axis of the tilted oriented birefringent layer is in the range of 90 ° ± 5 °. It is preferable that it is within a range of 90 ° ± 2 °. A laminated retardation film in which the slow axes of the oriented film and the tilted oriented birefringent layer are set in this way is particularly useful for optical compensation of, for example, VA cells and OCB cells. The slow axis (X axis) of the birefringent oriented film is in the same direction as the slow axis inside the film.

  Further, the in-plane retardation (Δnd) represented by the following formula of the birefringent oriented film is larger than the in-plane retardation (Δnd ′ ″) represented by the following formula of the tilted oriented birefringent layer. Preferably, “Δnd−Δnd ′ ″” is, for example, 10 to 300 nm, and preferably 20 to 140 nm. In the following formula, nx and ny are the same as described above, d is the thickness of the birefringent oriented film, nx ′ ″ and ny ′ ″ are the X-axis and Y-axis in the tilt-oriented birefringent layer, respectively. The X-axis direction is an axial direction indicating the maximum refractive index in the plane of the tilt-oriented birefringent layer, and the Y-axis is perpendicular to the X-axis in the plane. D ′ ″ represents the thickness of the tilted orientation birefringent layer.

Δnd = (nx−ny) · d
Δnd ′ ″ = (nx ′ ″ − ny ′ ″) · d ′ ″

  Specifically, the in-plane retardation (Δnd) of the birefringent oriented film is, for example, 10 to 200 nm, preferably 30 to 150 nm, more preferably 50 to 100 nm, and the thickness thereof is, for example, It is 4-6 micrometers, Preferably it is 4.5-5.8 micrometers, More preferably, it is 5-5.5 micrometers. On the other hand, the in-plane retardation of the tilted orientation birefringent layer is, for example, 50 to 500 nm, preferably 100 to 450 nm, more preferably 150 to 200 nm, and the thickness thereof is, for example, 0.5 to 5 μm, preferably Is 1 to 4.5 μm, more preferably 1.5 to 2 μm.

  Moreover, the thickness of the whole laminated retardation film is, for example, 4.5 to 11 μm, preferably 5.5 to 10.3 μm, more preferably 6.5 to 7.5 μm, and the in-plane retardation ( [Delta] nd) is, for example, 10 to 300 nm, preferably 30 to 200 nm, and more preferably 50 to 150 nm. Those having such a phase difference are particularly suitable for the VA mode and the OCB mode.

  The laminated retardation film of the present invention is measured in the direction of the measurement axis when the normal of the film surface is 0 ° and the angle between the normal and the measurement axis is a measurement angle (including 0 °). It is preferable that the phase difference value (Δnd) is asymmetric with respect to the measurement angle between the + side and the − side with the phase difference value at 0 ° as the center.

  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 phase of the laminated retardation film. It may be inclined in the axial direction, or may be inclined in the fast axis direction of the inclined optical compensation film.

  “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”. 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, the vertical axis at the measurement angle 0 ° (normal) as shown in FIG. In this state, the image is asymmetric with respect to the dotted line.

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

  Examples of the non-liquid crystalline polymer contained in the birefringent alignment film include polymers such as polyamide, polyimide, polyester, polyetherketone, polyaryletherketone, polyamideimide, and polyesterimide as described above.

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

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 ′ represents, 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, they may be the same or different. Each R ⁹ is independently hydrogen, fluorine, or chlorine.

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

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

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

In the above formulas (3) and (5), L is a substituent, and d and e represent the number of substitutions. L is, for example, halogen, C ₁ ~ ₃ alkyl group, C ₁ ~ ₃ halogenated alkyl group, a phenyl group, or a substituted phenyl group, in the case of multiple or different are each identical. Examples of the substituted phenyl group, for example, halogen, a substituted phenyl group having at least one substituent selected from C ₁ ~ ₃ alkyl group, and C ₁ ~ ₃ the group consisting of halogenated alkyl groups. Examples of the halogen include fluorine, chlorine, bromine and iodine. d is an integer from 0 to 2, and e is an integer from 0 to 3.

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

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

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

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

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

  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 1,4-diaminotoluene. And diamines selected from the group consisting of benzenediamines such as 3-diamino-4-chlorobenzene. Examples of the diaminobenzophenone include 2,2′-diaminobenzophenone and 3,3′-diaminobenzophenone. Examples of the 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, and 2,2′-bis ( Trifluoromethyl) -4,4'-diaminobiphenyl, 3,3'-dichloro-4,4'-diaminodiphenylmethane, 2,2'-dichloro-4,4'-diaminobiphenyl, 2,2 ', 5, 5′-tetrachlorobenzidine, 2,2-bis (4-aminophenoxyphenyl) propane, 2,2-bis (4-aminophenyl) propane, 2,2-bis (4-aminophenyl) -1,1, 1,3,3,3-hexafluoropropane, 4,4′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, 1,3-bis (3-aminophenoxy) benzene, 1,3-bis (4-amino) Phenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 4, '-Bis (4-aminophenoxy) biphenyl, 4,4'-bis (3-aminophenoxy) biphenyl, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4 -(4-aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane, 4,4′-diaminodiphenylthioether, 4,4′-diaminodiphenylsulfone, and the like.

  As said polyetherketone, the polyaryletherketone represented by following General formula (7) described in Unexamined-Japanese-Patent No. 2001-49110 is mention | raise | lifted, for example.

  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, lower alkyl groups are preferable linear 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 the formula (8), when there are a plurality of X ′, they are the same or different. q ′ represents the number of substitutions of X ′ and is an integer from 0 to 4, preferably q ′ = 0. P is an integer of 0 or 1.

In the formula (8), R ² represents a divalent aromatic group. Examples of the divalent aromatic group include 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, R ² is preferably an aromatic group selected from the group consisting of the following formulas (9) to (15).

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

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

  In addition to these, examples of the polyamide or polyester include polyamides and polyesters described in JP-T-10-508048, and their repeating units are represented by the following general formula (22), for example. Can be represented.

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 the E, R is at least one of C ₁ ~ ₃ alkyl group and C ₁ ~ ₃ halogenated alkyl group, in the meta or para position relative to the carbonyl functional group or a Y group.

  Moreover, in said (22), A and A 'are substituents and t and z represent each substitution number. 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.

Wherein A is selected from hydrogen, a halogen, C ₁ ~ ₃ alkyl group, C ₁ ~ ₃ halogenated alkyl group, OR (wherein, R represents those defined above.) The alkoxy group represented by aryl group, a substituted aryl group by a halogen, etc., C ₁ ~ ₉ alkoxycarbonyl group, C ₁ ~ ₉ alkylcarbonyloxy group, C ₁ ~ ₁₂ aryloxycarbonyl group, C ₁ ~ ₁₂ arylcarbonyloxy group and a substituted derivative thereof, C _1-12 arylcarbamoyl group, and is selected from the group consisting of C _1-12 arylcarbonylamino group and a substituted derivative thereof, in the case of a plurality, they may be the same or different. Wherein A 'is, for example, halogen, C ₁ ~ ₃ alkyl group, C ₁ ~ ₃ halogenated alkyl group, selected from the group consisting of phenyl group and a substituted phenyl group and when there are plural, they may be the same or different. The substituent on the phenyl ring of the substituted phenyl group, for example, halogen, C ₁ ~ ₃ alkyl group, C ₁ ~ ₃ alkyl halide groups and combinations thereof and the like. 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.

  On the other hand, the tilted alignment birefringent layer only needs to contain a rod-like liquid crystalline compound as described above. Examples of the rod-like liquid crystalline compound include the monomer liquid crystalline compound and the polymer liquid crystalline compound as described above. it can. When the rod-like liquid crystalline compound is a monomer liquid crystalline compound, it is particularly preferably a polymerizable monomer liquid crystalline compound. In the tilted alignment birefringent layer, the liquid crystallinity depends on the liquid crystallinity of the polymerizable monomer liquid crystalline compound. The compounds may be tilted and the monomer compounds may form a polymer by polymerization. In this case, the state of tilted alignment of the monomer liquid crystalline compound is fixed by polymerization, and the entire tilted birefringent layer becomes non-liquid crystalline by polymerization.

  Next, the optical film of the present invention is characterized by including at least one of the laminated retardation films of the present invention. The optical film only needs to include any one of the above-described films, and the configuration and structure other than that are not limited at all. For example, the optical film may further include various conventionally known optical layers. The optical layer is not particularly limited, and for example, various conventionally known various types used in various image display devices such as a polarizing element, various retardation plates, a diffusion control film, a brightness enhancement film, a reflective plate, and a transflective plate. An optical layer. 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 polarizing element may be, for example, a polarizer alone or a polarizing plate in which a transparent protective layer is laminated on at least one surface of the polarizer. The transparent protective layer may be laminated on both sides of the polarizer, or may be laminated only on one of the surfaces. Moreover, when laminating | stacking on both surfaces, the same kind of transparent protective layer may be used, for example, or a different kind of transparent protective layer may be used. Moreover, you may laminate | stack the optical film of this invention on the surface of the said polarizer as a film which serves as a transparent protective layer. When using the laminated retardation film of the present invention, either the surface-modified retardation film or the birefringent layer may be opposed to the polarizing element, but the birefringent layer may be laminated. preferable.

  The laminated retardation film and polarizing element of the present invention, and the polarizer and the transparent protective layer can be performed by a general method such as laminating via a conventionally known adhesive or pressure-sensitive adhesive. Further, the laminated retardation film and the polarizing element may only be bonded with the adhesive or the like. In addition to this, for example, it is possible to directly form the laminated retardation film of the present invention on the polarizer using the polarizer as a substrate.

  The polarizer (polarizing film) is not particularly limited, and is dyed by adsorbing a dichroic substance such as iodine or a dichroic dye on various films such as a polyvinyl alcohol film by a conventionally known method. And what was prepared by bridge | crosslinking, extending | stretching, and 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 film can be used. For example, a protective layer having excellent transparency, mechanical strength, thermal stability, moisture barrier property, isotropy and the like is preferable. Specific examples of the material for such a transparent protective layer include cellulose resins such as triacetyl cellulose, polyester, polycarbonate, polyamide, polyimide, polyethersulfone, polysulfone, polystyrene, and polynorbornene. Transparent resins such as polyethylene, polyolefin, acrylic, and acetate. Further, examples thereof include thermosetting resins such as acrylic, urethane, acrylic urethane, epoxy, and silicone, or ultraviolet curable resins. Among these, a TAC film whose surface is saponified with alkali or the like is preferable from the viewpoint of polarization characteristics and durability.

  Examples of the protective layer include polymer films described in JP-A-2001-343529 (WO01 / 37007). 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-methylmaleimide 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 element 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 tilted alignment layer of the discotic or nematic liquid crystal polymer is the above-mentioned. 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 element, 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 element, 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 light transmitted through the polarizing element due to reflection of external light on the surface of the polarizing element, 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 weight, more preferably in the range of 5 to 50 parts by weight per 100 parts by weight 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 element and expanding the viewing angle.

  The antireflection layer, antisticking layer, diffusion layer, antiglare layer, etc. are laminated on the polarizing element as an optical layer composed of, for example, a sheet provided with these layers, separately from the transparent protective layer. May be.

  As described above, the stacking of the components is not particularly limited, and can be performed by a conventionally known method. The type of the pressure-sensitive adhesive, the adhesive, or the like to be used 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. Further, an adhesive composed of a water-soluble crosslinking agent of vinyl alcohol polymers such as glutaraldehyde, melamine and oxalic acid can be used. 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 to 500 nm, preferably 10 to 300 nm, and more preferably 20 to 100 nm. The method is not particularly limited, and for example, a conventionally known method using an adhesive such as an acrylic polymer or a vinyl alcohol polymer can be employed. In addition, an adhesive containing a water-soluble cross-linking agent of PVA polymer such as glutaraldehyde, melamine, oxalic acid and the like can be obtained because it can form a polarizing element that is not easily peeled off by humidity, heat, etc. and has excellent light transmittance and polarization degree. preferable. These adhesives can be used by, for example, applying the aqueous solution to the surface of each component and drying. In the aqueous solution, for example, other additives and a catalyst such as an acid can be blended as necessary. Among these, as the adhesive, a PVA adhesive is preferable from the viewpoint of excellent adhesiveness with a PVA film.

  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 orientation scattering by the polarization direction, and the like can be used. . Moreover, the said optical film may contain the wire grid type polarizer, for example.

  Next, as an example of the optical film of the present invention, a reflective polarizing plate that further includes a reflective plate and a transflective reflective polarizing plate that further includes a semi-transmissive reflective plate will be described.

  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 composed of metal or the like on one surface of the surface-modified retardation film or laminated retardation film of the present invention. 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, as an example of the optical film of the present invention, a film on which a brightness enhancement film is further laminated will be described.

  The brightness enhancement film is not particularly limited. For example, it transmits linearly polarized light having a predetermined polarization axis, such as a dielectric multilayer thin film or a multilayer laminate of thin film films having different refractive index orientations. For example, the light having the characteristic of reflecting can be used. 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 optical film of the present invention as described above has, for example, a pressure-sensitive adhesive layer and an adhesive layer as its outermost layer because it can be easily laminated on other members such as a liquid crystal cell. These may be only one outermost layer or both outermost layers. The material of the adhesive layer is not particularly limited, and a conventionally known material such as an acrylic polymer can be used. In particular, foaming and peeling due to moisture absorption are prevented, optical characteristics are deteriorated due to a difference in thermal expansion, and a liquid crystal cell is warped. For example, it is preferable to form a pressure-sensitive adhesive layer having a low moisture absorption rate and excellent heat resistance, for example, from the viewpoints of prevention, and hence formability of a liquid crystal display device having high quality and excellent durability. Moreover, the adhesion layer etc. which contain microparticles | fine-particles and show light diffusibility may be sufficient. The pressure-sensitive adhesive layer is formed on the outermost layer by, for example, forming a layer by directly adding solutions or melts of various pressure-sensitive adhesive materials to the exposed surface of the optical film by a developing method such as casting or coating. It can be performed by a method, a method in which a pressure-sensitive adhesive layer is formed on a separator, which will be described later, and transferred to the exposed surface. Such a layer may be formed on any surface of the optical film.

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

  For example, the pressure-sensitive adhesive layer may be a single layer or a laminate. As the laminate, for example, a laminate in which different compositions and different types of single layers are combined can be used. Moreover, when arrange | positioning on both surfaces of an optical film, 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 optical film, and is generally 1 to 500 nm.

  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.

  The optical film of the present invention as described above and various members constituting the optical film are, for example, ultraviolet absorbers such as salicylic acid ester compounds, benzophenone compounds, benzotriazole compounds, cyanoacrylate compounds, nickel complex compounds, and the like. It may be provided with ultraviolet absorbing ability by appropriate treatment.

  The optical film of the present invention is particularly preferably used in a liquid crystal display device among image display devices. For example, the optical film of the present invention is disposed on one side or both sides of a liquid crystal cell to form a liquid crystal panel, and is reflective or transflective. It can be used for a liquid crystal display device such as a mold or a transmission / reflection type.

  The type of the liquid crystal cell forming the liquid crystal display device can be arbitrarily selected. For example, an active matrix driving type represented by a thin film transistor type, a simple matrix driving type represented by a twist nematic type or a super twist nematic type, and the like. Various types of liquid crystal cells can be used. Specifically, for example, STN (Super Twisted Nematic) cell, TN (Twisted Nematic) cell, IPS (In-Plan Switching) cell, VA (Vertical Nematic) cell, OCB (Optically Aligned Birefringence) cell, HAN (Hybrid Aligned) Nematic) cells, ASM (Axially Symmetric Aligned Microcell) cells, ferroelectric / antiferroelectric cells, and those in which regular alignment division is performed on these cells, and those in which random alignment division is performed are applicable. Among these, the optical film of the present invention is very useful as a viewing angle compensation film for a liquid crystal display device of TN mode and OCB mode because it is particularly excellent in optical compensation of TN cells and OCB cells.

  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 an optical member on both surfaces of a liquid crystal cell, you may arrange | position the optical film of this invention on both surfaces, and may arrange | position the optical film of this invention only to either one side. They may be of the same type or different. 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.

  The optical film of the present invention can be used for a self-luminous display device such as an organic electroluminescence (EL) display, PDP, FED, etc., in addition to the liquid crystal display device as described above. These image display devices need only have the optical film of the present invention, and are not particularly limited, and can have the same configuration and structure as conventional ones. When the optical film of the present invention is used in a self-luminous display device, for example, if the in-plane retardation value Δnd of the optical film of the present invention is λ / 4, circularly polarized light can be obtained. As very useful.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further more concretely, this invention is not limited to these.

(Example 1)
2,2′-bis (3,4-dicarboxyphenyl) hexafluoropropane and 2,2′-bis (trifluoromethyl) -4,4′-diaminobiphenyl) A polyimide powder was synthesized. The polyimide had a weight average molecular weight of 70,000.

  This polyimide powder was dissolved in methyl isobutyl ketone so as to be 20% by weight to prepare a polyimide solution. Then, the polyimide solution was continuously applied to the surface of a TAC film (length 200 m, width 350 mm, thickness 80 μm, manufactured by Fuji Photo Film) by a blade coating method, and the coating film was dried at 130 ° C. for 5 minutes. The thickness of the coating film after drying was 6.7 μm. Further, the coated film was stretched 1.3 times by the fixed end lateral stretching under the condition of 160 ° C. together with the TAC film. In addition, the draw ratio in this case means the magnification with respect to the length of an untreated coating film. By this stretching, the coating film was an optically negative biaxial polyimide film.

Subsequently, the surface of the biaxial polyimide film on the TAC film was irradiated with polarized UV light (wavelength 310 nm) for 30 minutes from a polarized UV exposure apparatus (irradiation energy 5 mW / cm ^{2 at a} wavelength of 310 nm; manufactured by Sen Engineering Co., Ltd.). . The polarized UV light was applied in the same direction as the stretching direction of the biaxial polyimide film, that is, the slow axis (X axis indicating the main refractive index nx). Thus, a polyimide film (birefringent alignment film) having a modified surface anisotropy was produced. A laminate of this TAC film and the birefringent oriented film was used as a substrate sample.

  On the other hand, 3 parts of a photoinitiator (trade name: Irgacure 369) is added to 100 parts of a polymerizable rod-like liquid crystal compound (trade name UCL-001: manufactured by Dainippon Ink & Chemicals), and the photoinitiator is added as described above. Dissolved in the liquid crystal compound. Butanol was further added to this solution so that the solid content was 20% by weight to prepare a coating solution. This coating solution was spin-coated on the polarized irradiation surface of the birefringent oriented film of the substrate sample at a rotation speed of 1000 rpm, and then this coating film was treated at 70 ° C. for 5 minutes, and then allowed to stand at room temperature. . By this heat treatment, the solvent was removed from the coating film and the isotropic phase transition was performed, and the mixture was allowed to stand at room temperature, thereby forming a liquid crystal layer in which the alignment state of the rod-like liquid crystal compound was inclined. Then, under a nitrogen purge (under a nitrogen atmosphere), the liquid crystal layer was irradiated with UV to polymerize the rod-like liquid crystalline compound in the liquid crystal layer, thereby forming a birefringent layer in which the alignment state was fixed. In this way, a laminated retardation film was produced in which a tilted oriented birefringent layer was directly laminated on the birefringent oriented film of the substrate sample.

(Reference Example 1)
In the same manner as in Example 1, a laminate of a TAC film and an optical biaxial polyimide film was prepared as a retardation film. The surface of the optical biaxial polyimide film is not irradiated with polarized light.

  About the obtained retardation film of Example 1 and Reference Example 1, the phase difference at 550 nm was measured using a spectroscopic ellipsometer (trade name M-220: manufactured by JASCO Corporation). In this retardation measurement, an in-plane normal of the laminated retardation film is set to 0 °, and −40 in the fast axis direction and the slow axis direction of the polyimide film from the normal line (0 °) and the normal line. The measurement was carried out from the direction of the measurement axis, with the axis inclined at 0 ° to + 40 ° as the measurement axis. These results are shown in FIG. 4 (Example) and FIG. 5 (Reference Example 1). Both figures are graphs showing the relationship between the measurement angle (tilt angle) and the phase difference value at each measurement angle. The horizontal axis represents the angle, the vertical axis represents the phase difference value, and the solid line represents the measurement axis. The phase difference value when tilted in the axial direction and the broken line indicate the phase difference value when the measurement axis is tilted in the slow axis direction.

  As shown in FIG. 4, the laminated phase difference film of Example 1 has a front phase difference (0 °) of 68 nm, and the retardation value curve when tilted in the fast axis direction is 0 ° (normal line). ) With respect to the vertical axis passing through. The slow axis and the fast axis of the laminated retardation film of Example 1 are in the same direction as the slow axis and the fast axis of the used optical biaxial polyimide film, respectively. As shown in FIG. 5, the laminated retardation film of Reference Example 1 has a front phase difference (0 °) of 113 nm and a position at a measurement angle (−40 to + 40 °) when the normal is 0 °. When the phase difference value curve was tilted in the fast axis direction and tilted in the slow axis direction, the curve was symmetrical with respect to the vertical axis passing through 0 ° (normal line).

  These results show the following. That is, when a liquid crystal layer is formed on the biaxial polyimide film surface of the retardation film of the reference example in the same manner as in Example 1, the rod-like liquid crystalline compound is anisotropic in the nature of the biaxial polyimide film. In accordance with the property (orientation), that is, along the slow axis (stretching direction) of the biaxial polyimide film. For this reason, for example, when it is desired to incline the rod-like liquid crystalline compound in the fast axis direction (perpendicular to the slow axis) of the biaxial polyimide film, a separate alignment film is formed on the biaxial polyimide film. It is understood that it is necessary to arrange. However, in Example 1, the tilted birefringent layer formed by irradiating the biaxial polyimide film with polarized light is different from the slow axis direction inside the biaxial polyimide film as shown in FIG. Inclined orientation in different directions (90 °) was shown. That is, according to the present invention, a tilted alignment birefringent layer having a controlled tilt direction is directly formed on a biaxial birefringent film by irradiating polarized light without providing a separate alignment film. You can see that The reason why the laminated phase difference film of Example 1 showed no object in the phase difference curve of the fast axis was because the polarized light irradiation was performed in the same direction as the slow axis of the biaxial polyimide film. This is because the liquid crystal compound is tilted and aligned in the fast axis direction which is perpendicular to the axis.

  As described above, according to the method for producing a laminated retardation film of the present invention, by designing the anisotropy of the surface of the biaxial birefringent film to be different from the internal anisotropy, the birefringent film ( On the birefringent oriented film), an inclined alignment birefringent layer inclined according to the anisotropy of the surface can be directly laminated. Such a laminated retardation film of the present invention does not require a separate alignment film in order to control the tilt direction of the tilted birefringent layer, for example, and thus can be reduced in thickness and variations in optical characteristics. Also spread. Therefore, it can be said that it is extremely useful for various image display devices including a liquid crystal display device.

It is a graph which shows an example of the relationship between the measurement angle of retardation, and retardation value in the lamination | stacking retardation film of this invention. It is a graph which shows the relationship between the measurement angle of retardation, and retardation value about the laminated retardation film in the Example of this invention. It is a graph which shows the relationship between the measurement angle of phase difference, and phase difference value about the laminated phase difference film in a reference example.

Claims (29)

When at least one surface of a birefringent polymer film exhibiting optical characteristics represented by the following formula (I) is irradiated with polarized light, only the surface of the polymer film irradiated with polarized light is changed in anisotropy to be compounded. Producing a refractive oriented film; and
On the surface irradiated with polarized light of the birefringent alignment film, a coating liquid containing a rod-like liquid crystalline compound is directly applied to form a coating film, and the coating film is subjected to a heat treatment to produce the rod-like liquid crystalline compound. A method for producing a laminated retardation film comprising a birefringent film and a tilted orientated birefringent layer, comprising a step of forming a tilted orientated birefringent layer by orienting in accordance with the anisotropy of the oriented film.
nx '>ny'> nz '(I)
In the formula (I), nx ′, ny ′, and nz ′ represent the refractive indexes in the X-axis, Y-axis, and Z-axis directions of the birefringent polymer film, respectively, An axial direction showing the maximum refractive index in the plane of the refractive polymer film, the Y axis is an axial direction perpendicular to the X axis in the plane, and the Z axis is the X axis and the Y axis. The thickness direction perpendicular to is shown. The manufacturing method according to claim 1, wherein the rod-like liquid crystalline compound is a liquid crystalline monomer compound, and the rod-like liquid crystalline compound is polymerized after heat-treating the coating film. The production method according to claim 1 or 2, wherein the birefringent polymer film is irradiated with polarized light in the same direction as a slow axis thereof. The manufacturing method according to claim 3, wherein an angle between a slow axis of the birefringent polymer film and an axis of polarized light to be irradiated is 0 ± 5 °. The manufacturing method according to claim 3, wherein an angle between a slow axis of the birefringent polymer film and an axis of polarized light to be irradiated is 0 ± 2 °. The production method according to claim 1, wherein the polarized light is linearly polarized light. The production method according to any one of claims 1 to 6, wherein the polarized light is ultraviolet polarized light. The production method according to claim 7, wherein the polarized light is ultraviolet polarized light of 200 to 400 nm. The said polymer film is a film containing a non-liquid crystalline polymer, The manufacturing method as described in any one of Claims 1-8. The production method according to claim 9, wherein the non-liquid crystalline polymer is at least one polymer selected from the group consisting of polyamide, polyimide, polyester, polyetherketone, polyaryletherketone, polyamideimide, and polyesterimide. A coating film is formed by coating a coating liquid containing a non-liquid crystalline polymer on a substrate surface, and a stretched film or a contracted film obtained by further stretching or shrinking the coated film is used as the oriented film. Item 11. The production method according to Item 10. The production method according to claim 11, wherein a birefringence (Δn) represented by the following formula of the coated film before stretching or shrinking is 0.01 or more.
Δn = nx ''-nz ''
In the above formula, nx ″ and nz ″ indicate the refractive indexes in the X-axis and Z-axis directions of the film, respectively, and the X-axis direction is the axial direction indicating the maximum refractive index in the plane of the film. And the Z-axis indicates the thickness direction perpendicular to the X-axis. The laminated phase difference film manufactured by the manufacturing method as described in any one of Claims 1-12. A laminated retardation film comprising a birefringent orientation film containing a non-liquid crystalline polymer, and a tilted birefringent layer in which a rod-like liquid crystalline compound is tilted,
The birefringent oriented film exhibits optical properties represented by the following formula (II):
At least one surface of the birefringent oriented film exhibits anisotropy different from the inside thereof,
The inclined birefringent layer is directly laminated on the surface showing anisotropy different from the inside in the birefringent oriented film,
The laminated retardation film, wherein in the tilted birefringent layer, the rod-like liquid crystalline compound is tilted according to the anisotropy of the surface of the birefringent oriented film.
nx>ny> nz (II)
In the formula (II), nx, ny, and nz respectively indicate refractive indexes in the X-axis, Y-axis, and Z-axis directions of the oriented film, and the X-axis direction is the maximum in the plane of the oriented film. The Y-axis is an axial direction perpendicular to the X-axis in the plane, and the Z-axis is a thickness direction perpendicular to the X-axis and the Y-axis. The laminated retardation film according to claim 14, wherein an angle between a slow axis of the birefringent oriented film and a slow axis of the tilted oriented birefringent layer is 90 ° ± 5 °. The laminated retardation film according to claim 14, wherein an angle between a slow axis of the birefringent oriented film and a slow axis of the tilted oriented birefringent layer is 90 ° ± 2 °.
The laminated retardation film according to any one of claims 14 to 16, wherein in the birefringent oriented film, an angle between the anisotropy of the surface and the internal anisotropy is 90 ° ± 5 °. The laminated retardation film according to any one of claims 14 to 17, wherein an in-plane retardation of the birefringent oriented film is larger than an in-plane retardation of the tilted oriented birefringent layer. The non-liquid crystalline polymer includes one polymer selected from the group consisting of polyamide, polyimide, polyester, polyetherketone, polyaryletherketone, polyamideimide, and polyesterimide. The laminated retardation film described. The laminated retardation film according to any one of claims 14 to 19, wherein the rod-like liquid crystalline compound is a liquid crystalline monomer compound, and the tilted alignment birefringent layer includes a polymer of the liquid crystalline monomer compound. The laminated retardation film according to any one of claims 14 to 19, wherein the rod-like liquid crystalline compound is a liquid crystalline polymer compound. When the normal of the film surface of the laminated retardation film is 0 °, and the angle between the normal and the measurement axis is a measurement angle (including 0 °),
The phase difference value (Δnd) 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 respect to the phase difference value at 0 °. The laminated phase difference film according to any one of to 21. When the normal of the film surface of the laminated retardation film is 0 °, the angle between the normal and the measurement axis is a measurement angle (including 0 °), and the measurement axis is inclined in the fast axis direction Further, the phase difference value (Δnd) 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. Item 22. The laminated retardation film according to any one of Items 14 to 21. The laminated retardation film according to any one of claims 14 to 23, wherein the retardation value (Δnd) of the oriented film is larger than the retardation value (Δnd) of the tilted orientation birefringent layer. An optical film comprising at least one of the laminated retardation films according to any one of claims 13 and 14-24. The optical film according to claim 25, further comprising a polarizing element. An image display device comprising the optical film according to claim 25 or claim 26. 28. The image display device according to claim 27, which is a liquid crystal display device. It is at least one self-luminous image display device selected from the group consisting of an electroluminescence (EL) display device, an organic electroluminescence (EL) display, a plasma display (PD), and an FED (Field Emission Display). The image display device according to claim 28.

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