JP2008256998A - Laminated optical film, liquid crystal panel using laminated optical film and liquid crystal display apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminated optical film which remarkably improves a contrast ratio in an oblique direction while improving a viewing angle characteristic when used for a liquid crystal display apparatus or the like and further to provide a liquid crystal panel using the laminated optical film and a liquid crystal display apparatus. <P>SOLUTION: The laminated optical film has a polarizer, a first optical compensation layer and a second optical compensation layer in this order. The first optical compensation layer has refractive index distribution of nx>nz>ny and is arranged so that its slow axis direction is substantially in parallel with or substantially vertical to an absorption axis direction of the polarizer. The second optical compensation layer has refractive index distribution of nx>ny>nz. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a laminated optical film, a liquid crystal panel using the laminated optical film, and a liquid crystal display device. More specifically, the present invention provides a laminated optical film capable of remarkably improving the contrast ratio in an oblique direction while improving viewing angle characteristics when used in a liquid crystal display device or the like, and such a laminated film The present invention relates to a liquid crystal panel and a liquid crystal display device using an optical film.

  As a VA mode liquid crystal display device, a transflective liquid crystal display device has been proposed in addition to a transmissive liquid crystal display device and a reflective liquid crystal display device (see, for example, Patent Documents 1 and 2). The transflective liquid crystal display device uses external light in a bright place in the same manner as the reflective liquid crystal display device, and allows display to be visually recognized by an internal light source such as a backlight in a dark place. In other words, the transflective liquid crystal display device employs a display method having both a reflective type and a transmissive type, and switches to either the reflective mode or the transmissive mode depending on the surrounding brightness. As a result, the transflective reflective liquid crystal display device can be clearly displayed even in a dark place while reducing power consumption, and is therefore preferably used for, for example, a display unit of a portable device.

  As a specific example of such a transflective reflective liquid crystal display device, for example, a reflective film in which a light transmissive window is formed on a metal film such as aluminum is provided on the inner side of the lower base material. A liquid crystal display device that functions as a transmission / reflection plate can be given. In such a liquid crystal display device, in the reflection mode, external light incident from the upper base material side is reflected by the reflective film inside the lower base material after passing through the liquid crystal layer and again passes through the liquid crystal layer. Then, it is emitted from the upper substrate side and contributes to display. On the other hand, in the case of the transmission mode, light from the backlight incident from the lower substrate side passes through the liquid crystal layer through the window of the reflective film, and then is emitted from the upper substrate side to contribute to display. . Therefore, in the reflective film formation region, the region where the window is formed is the transmissive display region, and the other region is the reflective display region. However, in the conventional reflective or transflective VA mode liquid crystal display device, there is a problem in that light leakage occurs in black display and the contrast is lowered, which has not been solved for a long time.

As an attempt to solve such a problem, for example, a laminated optical film using a retardation film having a wavelength dispersion characteristic in which the retardation value becomes smaller as the wavelength is shorter is proposed (see Patent Document 3). However, such a conventional laminated optical film has a problem that the viewing angle is insufficient and the practicality is inferior.
Japanese Patent Laid-Open No. 11-242226 Japanese Patent Laid-Open No. 2001-209065 JP 2004-326089 A

  The present invention has been made to solve the above-described conventional problems, and the object of the present invention is to dramatically improve the contrast ratio in the oblique direction while improving the viewing angle characteristics when used in a liquid crystal display device or the like. It is to provide a laminated optical film that can be improved and a liquid crystal panel and a liquid crystal display device using such a laminated optical film.

The laminated optical film of the present invention is
Having a polarizer, a first optical compensation layer, and a second optical compensation layer in this order;
The first optical compensation layer has a refractive index distribution of nx>nz> ny, and is arranged so that a slow axis direction thereof is substantially parallel or substantially orthogonal to the absorption axis direction of the polarizer. ,
The second optical compensation layer has a refractive index distribution of nx>ny> nz.

  In a preferred embodiment, the Nz coefficient of the first optical compensation layer is 0.1 to 0.6.

  In a preferred embodiment, the first optical compensation layer is composed of a single retardation film (A).

  In preferable embodiment, the said retardation film (A) contains the at least 1 sort (s) of thermoplastic resin selected from norbornene-type resin, a cellulose-type resin, carbonate-type resin, and ester-type resin.

  In a preferred embodiment, the second optical compensation layer is composed of one retardation film (B), and the slow axis direction of the retardation film (B) is relative to the absorption axis direction of the polarizer. Arranged at an angle of substantially 45 °.

  In preferable embodiment, the said retardation film (B) contains the at least 1 sort (s) of thermoplastic resin selected from norbornene-type resin and carbonate-type resin.

  In a preferred embodiment, a third optical compensation layer having a refractive index distribution of nx = ny> nz is disposed on the opposite side of the second optical compensation layer from the first optical compensation layer.

  According to another aspect of the present invention, a liquid crystal panel is provided. The liquid crystal panel includes the laminated optical film and a liquid crystal cell.

  According to still another aspect of the present invention, a liquid crystal display device is provided. The liquid crystal display device includes the liquid crystal panel.

  As described above, according to the present invention, when used in a liquid crystal display device or the like, a laminated optical film capable of remarkably improving a contrast ratio in an oblique direction while improving viewing angle characteristics, and such A liquid crystal panel and a liquid crystal display device using a laminated optical film can be provided.

  Such an effect is that a laminated optical film has a polarizer, a first optical compensation layer, and a second optical compensation layer in this order, and the first optical compensation layer has nx> nz> ny. And the second optical compensation layer is arranged such that nx> ny>, the slow axis direction of which is substantially parallel to or substantially perpendicular to the absorption axis direction of the polarizer. It can be expressed by adopting a film having a refractive index distribution of nz.

  That is, the synergistic effect of the combination of the optical characteristics of each optical compensation layer and their arrangement method, when used in a liquid crystal display device, etc., compared with conventional laminated optical films, while improving the viewing angle characteristics, The contrast ratio in the oblique direction can be remarkably improved.

(Definition of terms and symbols)
Definitions of terms and symbols used herein are as follows:

  (1) “nx” is the refractive index in the direction in which the in-plane refractive index is maximum (ie, the slow axis direction), and “ny” is the direction perpendicular to the slow axis in the plane (ie, fast phase). (Nz direction), and “nz” is the refractive index in the thickness direction. For example, “nx = ny” includes not only the case where nx and ny are exactly equal, but also the case where nx and ny are substantially equal. In this specification, “substantially equal” is intended to include the case where nx and ny are different within a range that does not practically affect the overall polarization characteristics of the laminated optical film. Therefore, for example, the description of nx = ny includes the case where the in-plane retardation Re [590] described below is less than 10 nm.

  (2) “In-plane retardation Re [590]” refers to an in-plane retardation value measured with light having a wavelength of 590 nm at 23 ° C. Re [590] is an equation when the refractive index in the slow axis direction and the fast axis direction of the film (layer) at a wavelength of 590 nm is nx and ny, respectively, and d (nm) is the thickness of the film (layer). : Re [λ] = (nx−ny) × d. Similarly, for example, “in-plane retardation Re [550]” refers to the in-plane retardation value measured with light having a wavelength of 550 nm at 23 ° C. When simply described as “Re”, unless otherwise specified, it means a retardation value in the plane of the film (layer) measured with light having a wavelength of 590 nm at 23 ° C.

  (3) “Thickness direction retardation Rth [590]” refers to a thickness direction retardation value measured with light having a wavelength of 590 nm at 23 ° C. Rth [590] is the formula: Rth when the refractive index in the slow axis direction and the thickness direction of the film (layer) at a wavelength of 590 nm is nx and nz, respectively, and d (nm) is the thickness of the film (layer). [Λ] = (nx−nz) × d. Similarly, for example, “thickness direction retardation Rth [550]” means a thickness direction retardation value measured at 23 ° C. with light having a wavelength of 550 nm. When simply described as “Rth”, unless otherwise specified, it means a retardation value in the thickness direction measured with light having a wavelength of 590 nm at 23 ° C.

  (4) The “Nz coefficient” is a value calculated by Nz = Rth [590] / Re [590].

  (5) In this specification, “substantially parallel” includes a case where an angle formed by two optical axes is 0 ° ± 2 °, and preferably 0 ° ± 1 °. In this specification, “substantially orthogonal” includes a case where an angle formed by two optical axes is 90 ° ± 2 °, and preferably 90 ° ± 1 °.

  (6) The subscript “1” attached to the terms and symbols described in this specification represents the first optical compensation layer, and the subscript “2” represents the second optical compensation layer. The letter “3” represents the third optical compensation layer.

  (7) “λ / 2 plate” refers to converting linearly polarized light having a specific vibration direction into linearly polarized light having a vibration direction orthogonal to the vibration direction of the linearly polarized light, or converting right circularly polarized light to the left circle It has a function of converting into polarized light (or converting left circularly polarized light into right circularly polarized light). The λ / 2 plate has an in-plane retardation value of about ½ for a predetermined wavelength of light (usually in the visible light region).

  (8) “λ / 4 plate” means a plate having a function of converting linearly polarized light having a specific wavelength into circularly polarized light (or circularly polarized light into linearly polarized light). The λ / 4 plate has an in-plane retardation value of about ¼ for a predetermined wavelength of light (usually in the visible light region).

  (9) In the present invention, the axial angle of + α ° has an axial angle of α ° counterclockwise when viewed from the direction in which the liquid crystal cell can finally be arranged (the direction in which the adhesive layer can be formed). Means that.

[A. Laminated optical film]
[A-1. Overall configuration of laminated optical film]
FIG. 1 is a schematic cross-sectional view of a laminated optical film according to a preferred embodiment of the present invention. It should be noted that, in order to make the drawing easier to see, the ratio of the vertical, horizontal, and thickness of each component in the drawing is different from the actual ratio.

  As shown in FIG. 1, the laminated optical film 10 includes a polarizer 20, a first optical compensation layer 30, and a second optical compensation layer 40 at least in this order.

  The first optical compensation layer 30 has a refractive index distribution of nx> nz> ny. The first optical compensation layer 30 is disposed so that the slow axis direction thereof is substantially parallel or substantially orthogonal to the absorption axis direction of the polarizer 20.

  The second optical compensation layer 40 has a refractive index distribution of nx> ny> nz.

  The laminated optical film having the structure shown in FIG. 1 functions as a circularly polarizing plate when used in a liquid crystal display device, and has a significantly higher contrast ratio in an oblique direction than a conventional laminated optical film. Can be obtained. The laminated optical film having the structure as shown in FIG. 1 exhibits particularly excellent effects when used as one circularly polarizing plate of a transmission type liquid crystal display device using two circularly polarizing plates.

  Practically, any appropriate protective layer (not shown) or surface treatment layer (not shown) may be laminated on the side of the polarizer 20 where the first optical compensation layer 30 is not formed. . Furthermore, any appropriate protective layer (not shown) may be provided between the polarizer 20 and the first optical compensation layer 30 as necessary.

  Arbitrary appropriate adhesive layers (not shown in FIG. 1) may be provided between the constituent members (polarizer, optical compensation layers, etc.) of the laminated optical film of the present invention. In the present invention, the “adhesive layer” refers to a layer obtained by joining the surfaces of adjacent members and integrating them with practically sufficient adhesive force and adhesion time. Examples of the material for forming the adhesive layer include an adhesive, a pressure-sensitive adhesive, and an anchor coating agent. The adhesive layer may have a multilayer structure in which an anchor coat layer is formed on the surface of the adherend, and an adhesive layer or a pressure-sensitive adhesive layer is formed on the anchor coat layer. The adhesive layer may be a thin layer (also referred to as a hairline) that cannot be visually recognized.

  In consideration of practicality, the total thickness of the laminated optical film of the present invention is preferably 200 to 420 μm, more preferably 210 to 410 μm, and further preferably 220 to 400 μm.

[A-2. First optical compensation layer]
The first optical compensation layer is disposed between the polarizer and the second optical compensation layer. In the present invention, the arrangement of the first optical compensation layer is important in order to obtain a laminated optical film capable of obtaining a liquid crystal display device having a significantly higher contrast ratio in an oblique direction than a conventional laminated optical film. is there. When the arrangement of the first optical compensation layer is changed, for example, a laminated optical film including a polarizer, a second optical compensation layer, and a first optical compensation layer in this order is used in a liquid crystal display device. There is a possibility that an excellent contrast ratio in an oblique direction cannot be obtained.

  The first optical compensation layer preferably also serves as a protective layer for the polarizer. That is, it is not necessary to provide a separate protective layer between the polarizer and the first optical compensation layer. In this case, the first optical compensation layer is preferably bonded to the surface of the polarizer via an adhesive layer.

  The first optical compensation layer has a refractive index distribution of nx> nz> ny. The first optical compensation layer acts so as to correct the geometric axis deviation of the polarizing plate when viewed from an oblique direction.

  The first optical compensation layer is arranged so that the slow axis direction thereof is substantially parallel or substantially perpendicular to the absorption axis direction of the polarizer.

  When the laminated optical film of the present invention is used as one circular polarizing plate of a transmission type liquid crystal display device using two circular polarizing plates, the first optical compensation layer has absorption axes of two polarizers. It has a function of optically compensating that the positional relationship changes between the front direction and the oblique direction.

  The total thickness of the first optical compensation layer is preferably 20 to 500 μm. When the first optical compensation layer has a thickness in such a range, a liquid crystal display device excellent in optical uniformity can be obtained.

The transmittance (T ₁ ) at a wavelength of 590 nm of the first optical compensation layer is preferably 80% or more.

Re ₁ [590] of the _first optical compensation layer is preferably 150 to 350 nm, more preferably 180 to 300 nm, and further preferably 250 to 300 nm.

  The Nz coefficient of the first optical compensation layer is preferably 0.1 to 0.6, and more preferably 0.15 to 0.55.

By setting the Re ₁ [590] and the Nz coefficient of the first optical compensation layer in the above ranges, a laminated optical film that can obtain a liquid crystal display device having a remarkably high contrast ratio in an oblique direction can be obtained. In particular, when the Nz coefficient of the first optical compensation layer is 0.5, it is possible to achieve a characteristic in which the retardation value is substantially constant regardless of the angle, and thus the above effect is easily achieved, which is preferable.

  The first optical compensation layer may be a single layer or a laminate composed of a plurality of layers. Preferably, the first optical compensation layer is composed of one retardation film (A). According to such a form, the thickness of the laminated optical film of the present invention can be reduced. In particular, when the first optical compensation layer also serves as a protective layer for the polarizer, the effect becomes more remarkable. As an effect in the case where the first optical compensation layer also serves as a protective layer of the polarizer, there is a point that the possibility of receiving a problem due to the influence of the retardation of the protective layer can be reduced.

The absolute value (C _A [590] (m ² / N)) of the photoelastic coefficient of the first optical compensation layer is preferably 1 × 10 ^{−12 to} 6 × 10 ⁻¹² , more preferably 1 × 10 6. ^-12 is a ~6 × ^{10 -12.} When C _A [590] is within the above range, a liquid crystal display device excellent in display uniformity can be obtained.

  The retardation film (A) can be formed of any appropriate material as long as the above properties are obtained. Preferably, the retardation film (A) contains at least one thermoplastic resin selected from norbornene-based resins, cellulose-based resins, carbonate-based resins, and ester-based resins. The retardation film (A) preferably contains 60 to 100 parts by weight of the resin with respect to 100 parts by weight of the total solid content.

  In the present specification, the “thermoplastic resin” includes a polymer having a degree of polymerization of 20 or more and a large weight average molecular weight (so-called high polymer), and further having a degree of polymerization of 2 or more and less than 20, Includes polymers having an average molecular weight of about several thousand (so-called low polymers: sometimes referred to as oligomers).

  In the present specification, the “resin” may be a homopolymer obtained from one kind of monomer or a copolymer obtained from two or more kinds of monomers. .

  The retardation film (A) more preferably contains at least one thermoplastic resin selected from norbornene resins and carbonate resins. It is because it is excellent in heat resistance, transparency, and moldability.

  The weight average molecular weight of the thermoplastic resin is preferably 20,000 to 500,000 as measured by a gel permeation chromatograph (GPC) method using a tetrahydrofuran solvent. As for the glass transition temperature (Tg) of the thermoplastic resin, a value determined by a DSC method according to JIS K 7121 is preferably 110 ° C to 180 ° C. By setting the weight average molecular weight and the glass transition temperature within the above ranges, a retardation film (A) having good heat resistance and moldability can be obtained.

  The norbornene-based resin is a resin that is polymerized using a norbornene-based monomer as a polymerization unit.

  Examples of the norbornene-based monomer include norbornene and alkyl and / or alkylidene substituted products thereof such as 5-methyl-2-norbornene, 5-dimethyl-2-norbornene, 5-ethyl-2-norbornene, and 5-butyl. 2-Norbornene, 5-ethylidene-2-norbornene, and the like, polar substituents such as halogens thereof; dicyclopentadiene, 2,3-dihydrodicyclopentadiene, etc .; dimethanooctahydronaphthalene, its alkyl and / or alkylidene Substituents and polar group substituents such as halogen such as 6-methyl-1,4: 5,8-dimethano-1,4,4a, 5,6,7,8,8a-octahydronaphthalene, 6- Ethyl-1,4: 5,8-dimethano-1,4,4a, 5,6,7,8,8a-oct Hydronaphthalene, 6-ethylidene-1,4: 5,8-dimethano-1,4,4a, 5,6,7,8,8a-octahydronaphthalene, 6-chloro-1,4: 5,8-dimethano -1,4,4a, 5,6,7,8,8a-octahydronaphthalene, 6-cyano-1,4: 5,8-dimethano-1,4,4a, 5,6,7,8,8a -Octahydronaphthalene, 6-pyridyl-1,4: 5,8-dimethano-1,4,4a, 5,6,7,8,8a-octahydronaphthalene, 6-methoxycarbonyl-1,4: 5 8-dimethano-1,4,4a, 5,6,7,8,8a-octahydronaphthalene and the like; 3-pentamer of cyclopentadiene, for example, 4,9: 5,8-dimethano-3a, 4 4a, 5,8,8a, 9,9a-octahydro-1H-benzoin 4,11: 5,10: 6,9-trimethano-3a, 4,4a, 5,5a, 6,9,9a, 10,10a, 11,11a-dodecahydro-1H-cyclopentanthracene and the like. It is done. The norbornene-based resin may be a copolymer of a norbornene-based monomer and another monomer. In the case of a copolymer, any appropriate arrangement state can be adopted as the arrangement state of the molecule. For example, a random copolymer, a block copolymer, or a graft copolymer may be used.

  Examples of the norbornene resin include a resin obtained by hydrogenating a ring-opening (co) polymer of a norbornene monomer and a resin obtained by addition (co) polymerization of a norbornene monomer. A resin obtained by hydrogenating a ring-opening (co) polymer of the norbornene monomer is formed by opening one or more norbornene monomers with at least one selected from α-olefins, cycloalkenes, and non-conjugated dienes. It includes a resin obtained by hydrogenating a ring (co) polymer. The resin obtained by addition (co) polymerization of the norbornene monomer is addition (co) polymerization of one or more norbornene monomers and at least one selected from α-olefins, cycloalkenes and non-conjugated dienes. Resin.

  A resin obtained by hydrogenating a ring-opening (co) polymer of the norbornene monomer is subjected to a metathesis reaction of the norbornene monomer or the like to obtain a ring-opening (co) polymer, and the ring-opening (co) polymer is further hydrogenated. It can be obtained by adding. Specifically, for example, the method described in paragraphs 0059 to 0060 of JP-A-11-116780 and the method described in paragraphs 0035 to 0037 of JP-A-2001-350017 are exemplified. The resin obtained by addition (co) polymerization of the norbornene monomer can be obtained, for example, by the method described in Example 1 of JP-A No. 61-292601.

  As the polycarbonate resin, an aromatic polycarbonate is preferably used. The aromatic polycarbonate can be typically obtained by a reaction between a carbonate precursor and an aromatic dihydric phenol compound. Specific examples of the carbonate precursor include phosgene, bischloroformate of dihydric phenols, diphenyl carbonate, di-p-tolyl carbonate, phenyl-p-tolyl carbonate, di-p-chlorophenyl carbonate, dinaphthyl carbonate and the like. Can be mentioned. Among these, phosgene and diphenyl carbonate are preferable. Specific examples of the aromatic dihydric phenol compound include 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, and bis (4-hydroxyphenyl). ) Methane, 1,1-bis (4-hydroxyphenyl) ethane, 2,2-bis (4-hydroxyphenyl) butane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) butane, 2, 2-bis (4-hydroxy-3,5-dipropylphenyl) propane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethyl And cyclohexane. You may use these individually or in combination of 2 or more types. Preferably, 2,2-bis (4-hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane are Used. In particular, it is preferable to use both 2,2-bis (4-hydroxyphenyl) propane and 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane.

  The retardation film (A) may contain any appropriate other thermoplastic resin. Other thermoplastic resins include polyolefin resins, polyvinyl chloride resins, cellulose resins, styrene resins, acrylonitrile / butadiene / styrene resins, acrylonitrile / styrene resins, polymethyl methacrylate, polyvinyl acetate, and polychlorinated resins. General-purpose plastics such as vinylidene resins; general-purpose engineering plastics such as polyamide resins, polyacetal resins, polycarbonate resins, modified polyphenylene ether resins, polybutylene terephthalate resins, polyethylene terephthalate resins; polyphenylene sulfide resins, polysulfone resins , Polyethersulfone resin, polyetheretherketone resin, polyarylate resin, liquid crystalline resin, polyamideimide resin, polyimide resin, polyester Super engineering plastics such as La fluoroethylene resin and the like.

  Any appropriate method can be adopted as a method for producing the retardation film (A). Typically, for example, a thermoplastic resin or a composition containing the thermoplastic resin is formed into a sheet shape to form a polymer film, and a shrinkable film is bonded to one or both sides of the polymer film, The method of extending by heating is mentioned. Examples of the heat stretching include heat stretching by a longitudinal uniaxial stretching method using a roll stretching machine.

  The polymer film can be obtained by any appropriate forming method. Examples of the molding method include compression molding, transfer molding, injection molding, extrusion molding, blow molding, powder molding, FRP molding, and solvent casting.

  The shrinkable film is used for imparting a shrinkage force in a direction orthogonal to the stretching direction during heat stretching. Thereby, the shrinkage rate (nz) in the thickness direction can be increased. Examples of the material used for the shrinkable film include polyester, polystyrene, polyethylene, polypropylene, polyvinyl chloride, and polyvinylidene chloride. From the viewpoint of excellent shrinkage uniformity and heat resistance, a polypropylene film is preferably used. Examples of a method for bonding a shrinkable film on both surfaces of the polymer film include, for example, a method in which a pressure-sensitive adhesive layer is provided and bonded between the polymer film and the shrinkable film, productivity, workability, and It is preferable from the point of being economical. As a method for increasing or decreasing the Nz coefficient of the retardation film (A), for example, a shrinkable film having a large shrinkage rate in the width direction is preferably used. For example, the shrinkage rate in the width direction at 140 ° C. is 5% to 15%.

  As a method for stretching the polymer film, any suitable stretching method can be adopted depending on the purpose. Examples of the stretching method include a longitudinal uniaxial stretching method, a transverse uniaxial stretching method, a longitudinal and transverse simultaneous biaxial stretching method, and a longitudinal and transverse sequential biaxial stretching method. The stretching direction may be the longitudinal direction (MD direction) of the film or the width direction (TD direction). Moreover, you may extend | stretch in the diagonal direction (diagonal extending | stretching) using the extending | stretching method of FIG. 1 of Unexamined-Japanese-Patent No. 2003-262721.

  Any appropriate stretching condition can be adopted as the stretching condition. The stretching temperature is preferably equal to or higher than the glass transition temperature (Tg) of the polymer film. This is because the retardation value of the obtained stretched film is likely to be uniform, and the film is difficult to crystallize (white turbidity). The stretching temperature is more preferably Tg + 1 ° C. to Tg + 30 ° C., more preferably Tg + 2 ° C. to Tg + 20 ° C., particularly preferably Tg + 3 ° C. to Tg + 15 ° C., and most preferably Tg + 5 ° C. to Tg + 10 ° C. By setting the stretching temperature in such a range, uniform heating and stretching can be performed. Furthermore, the stretching temperature is preferably constant in the film width direction. This is because a stretched film having good optical uniformity with small variations in retardation value can be produced. The draw ratio can be set to any appropriate value. Preferably more than 1 time and 3 times or less, more preferably 1.05 to 2.00 times, still more preferably 1.10 to 1.50 times, particularly preferably 1.20 to 1.40 times, most preferably 1 .25 to 1.30 times. By setting the draw ratio in such a range, a stretched film having little mechanical shrinkage and excellent mechanical strength can be obtained. The feeding speed at the time of stretching is preferably 0.5 m / min to 30 m / min in view of mechanical accuracy, stability and the like. By selecting such conditions, it is possible to obtain a retardation film having a uniform retardation value and high transparency.

  An example of a method for producing the retardation film (A) will be described with reference to FIG. FIG. 2 is a schematic diagram showing the concept of a typical production process of the retardation film (A) used in the present invention. For example, the polymer film 402 containing a thermoplastic resin is fed out from the first feeding unit 401, and fed out from the second feeding unit 403 on both surfaces of the polymer film 402 by the laminate rolls 407 and 408. The shrinkable film 404 including the pressure-sensitive adhesive layer and the shrinkable film 406 including the pressure-sensitive adhesive layer fed out from the third feeding portion 405 are bonded together. The polymer film having the shrinkable film attached on both sides is given a tension in the longitudinal direction of the film by rolls 410, 411, 412 and 413 having different speed ratios while being held at a constant temperature by the heating means 409 ( At the same time, the film is subjected to a stretching treatment while being given a tension in the thickness direction by the shrinkable film. The stretched film 418 is peeled off at the first winding portion 414 and the second winding portion 416 together with the shrinkable films 404 and 406 together with the pressure-sensitive adhesive layer, and wound at the third winding portion 419. It is done.

[A-3. Second optical compensation layer]
The second optical compensation layer has a refractive index distribution of nx>ny> nz.

The second optical compensation layer can function as a so-called λ / 4 plate. According to the present invention, the wavelength dispersion characteristic of the second optical compensation layer functioning as a λ / 4 plate is corrected by the optical characteristic of the first optical compensation layer functioning as the λ / 2 plate, thereby obtaining a wide wavelength range. The circular polarization function in a range can be exhibited. The second optical compensation layer has a refractive index ellipsoid of nx>ny> nz. The in-plane retardation Re ₂ [590] of the second optical compensation layer is preferably 90 to 160 nm, more preferably 110 to 155 nm, and further preferably 130 to 150 nm.

  The Nz coefficient of the second optical compensation layer is preferably 1 <Nz <2, more preferably 1 <Nz <1.8.

  The second optical compensation layer can be formed of any appropriate material. Specific examples include stretched films of polymer films. The resin forming the polymer film is preferably a norbornene resin or a polycarbonate resin. Details of these resins are as described above in section A-2. Arbitrary appropriate methods can be employ | adopted as a preparation method of a stretched film. Examples of the stretching method include lateral uniaxial stretching (fixed end biaxial stretching) and sequential biaxial stretching. The stretching temperature is preferably 135 to 165 ° C, more preferably 140 to 160 ° C. The draw ratio is preferably 2.8 to 3.2 times, more preferably 2.9 to 3.1 times. In this case, the thickness is typically 20 to 80 μm, preferably 25 to 75 μm, and more preferably 30 to 60 μm.

  Another specific example of the material forming the second optical compensation layer is a non-liquid crystalline material. A non-liquid crystalline polymer is preferable. Specifically, polymers such as polyamide, polyimide, polyester, polyetherketone, polyamideimide, and polyesterimide are preferable. These polymers may be used alone or in a mixture of two or more. Among these, polyimide is particularly preferable because of high transparency, high orientation, and high stretchability.

  The second optical compensation layer can be typically formed by applying a solution of the non-liquid crystal polymer to a base film and removing the solvent. In the method for forming the second optical compensation layer, preferably, a process for imparting optical biaxiality (nx> ny> nz) (for example, a stretching process) is performed. By performing such processing, a difference in refractive index (nx> ny) can be reliably imparted in the surface. In addition, as a specific example of the said polyimide and the specific example of the formation method of the said 2nd optical compensation layer, the manufacturing method of the polymer and optical compensation film of Unexamined-Japanese-Patent No. 2006-234848 are mentioned. In this case, the thickness is typically 0.1 to 10 μm, more preferably 0.1 to 8 μm, and particularly preferably 0.1 to 5 μm.

  Whether the second optical compensation layer has a function of converting linearly polarized light into circularly polarized light or a function of converting circularly polarized light into linearly polarized light, when the laminated optical film of the present invention is used in a liquid crystal display device, It can be determined by the positional relationship between the position of the laminated optical film and the light source. For example, when the light source of the liquid crystal display device is a backlight and the laminated optical film is disposed on the backlight side of the liquid crystal cell, the second optical compensation layer has a function of converting linearly polarized light into circularly polarized light. Alternatively, when the light source of the liquid crystal display device is a backlight and the laminated optical film is disposed on the viewing side of the liquid crystal cell, the second optical compensation layer has a function of converting circularly polarized light into linearly polarized light.

The transmittance (T ₂ ) at a wavelength of 590 nm of the second optical compensation layer is preferably 80% or more. The absolute value (C _B [590] (m ² / N)) of the photoelastic coefficient of the second optical compensation layer is preferably 1 × 10 ^{−12 to} 100 × 10 ⁻¹² , more preferably 1 × 10 6. ^-12 is a ~60 × ^{10 -12.} A liquid crystal display device excellent in display uniformity can be obtained by using a material having C _B [590] in the above range.

  Preferably, the slow axis direction of the second optical compensation layer is arranged so as not to be substantially parallel or orthogonal to the absorption axis direction of the polarizer. An example of the second optical compensation layer will be described with reference to FIG.

  FIG. 3 is a schematic perspective view of a laminated optical film in a preferred embodiment of the present invention. It should be noted that, in order to make the drawing easier to see, the ratio of the vertical, horizontal, and thickness of each component in the drawing is different from the actual ratio.

  In one embodiment, as shown in FIG. 3, the laminated optical film 10 of the present invention includes the second optical compensation layer 40 formed by one retardation film (B) 41, and the polarizer 20. The angle formed between the absorption axis direction of the film and the slow axis direction of the retardation film (B) 41 is substantially 45 °. In this specification, “substantially 45 °” includes 45 ° ± 5 °. In the illustrated example, the case where the absorption axis direction of the polarizer 20 is substantially orthogonal to the slow axis direction of the first optical compensation layer 30 is shown, but this is substantially parallel. May be.

[A-4. Third optical compensation layer]
In the laminated optical film of the present invention, a third optical compensation layer having a refractive index distribution of nx = ny> nz is arranged on the opposite side of the second optical compensation layer from the first optical compensation layer. May be. Here, “nx = ny” includes not only the case where nx and ny are exactly equal, but also the case where nx and ny are substantially equal. That is, Re ₃ is less than 10 nm. The thickness direction retardation Rth3 of the _third optical compensation layer can be set to any appropriate value depending on the configuration of the applied liquid crystal panel. For example, when the third optical compensation layer is disposed only on one side of the liquid crystal cell, the thickness direction retardation Rth ₃ is preferably 50 to 600 nm, more preferably 80 to 540 nm, and particularly preferably 100 to 300 nm. It is. On the other hand, when the third optical compensation layer is disposed on both sides of the liquid crystal cell, the thickness direction retardation Rth ₃ is preferably 25 to 300 nm, more preferably 40 to 270 nm, and particularly preferably 50 to 150 nm.

  The third optical compensation layer can be formed of any appropriate material as long as the above characteristics are obtained. A specific example of the third optical compensation layer is a cholesteric alignment solidified layer. The “cholesteric alignment solidified layer” refers to a layer in which the constituent molecules of the layer have a helical structure, the helical axis is aligned substantially perpendicular to the plane direction, and the alignment state is fixed. Therefore, the “cholesteric alignment solidified layer” includes not only the case where the liquid crystal compound exhibits a cholesteric liquid crystal phase but also the case where the non-liquid crystal compound has a pseudo structure such as a cholesteric liquid crystal phase. For example, the “cholesteric alignment solidified layer” is obtained by applying a torsion with a chiral agent in a state where the liquid crystal material exhibits a liquid crystal phase and aligning it in a cholesteric structure (spiral structure), and performing a polymerization treatment or a crosslinking treatment in that state. It can be formed by fixing the alignment (cholesteric structure) of the liquid crystal material.

  Specific examples of the cholesteric alignment fixed layer include a cholesteric layer described in JP-A No. 2003-287623.

  The thickness of the third optical compensation layer can be set to any appropriate value as long as the desired optical characteristics are obtained. When the third optical compensation layer is a cholesteric alignment fixed layer, it is preferably 0.5 to 10 μm, more preferably 0.5 to 8 μm, and particularly preferably 0.5 to 5 μm.

  Another specific example of the material forming the third optical compensation layer is a non-liquid crystalline material. Particularly preferred are non-liquid crystalline polymers. Unlike the liquid crystalline material, such a non-liquid crystalline material can form a film exhibiting an optical uniaxial property of nx = ny> nz by its own property regardless of the orientation of the substrate. As the non-liquid crystalline material, for example, polymers such as polyamide, polyimide, polyester, polyetherketone, polyamideimide, and polyesterimide are preferable because they are excellent in heat resistance, chemical resistance, transparency, and rigidity. Any one of these polymers may be used alone, or a mixture of two or more having different functional groups such as a mixture of polyaryletherketone and polyamide may be used. . Among such polymers, polyimide is particularly preferable because of its high transparency, high orientation, and high stretchability.

  Specific examples of the polyimide and the method for forming the third optical compensation layer include a polymer and a method for producing an optical compensation film described in JP-A-2004-46065.

  The thickness of the third optical compensation layer can be set to any appropriate value as long as the desired optical characteristics are obtained. When the third optical compensation layer is formed of a non-liquid crystal material, it is preferably 0.5 to 10 μm, more preferably 0.5 to 8 μm, and particularly preferably 0.5 to 5 μm.

  Still another specific example of the material forming the third optical compensation layer includes a polymer film formed of a cellulose resin such as triacetyl cellulose (TAC), a norbornene resin, or the like. A commercially available film can be used as it is as the third optical compensation layer. Further, a commercially available film subjected to secondary processing such as stretching and / or shrinking can be used. As commercially available films, for example, Fuji Photo Film Co., Ltd. Fujitac series (trade names; ZRF80S, TD80UF, TDY-80UL), Konica Minolta Opto Co., Ltd. trade names “KC8UX2M”, Nippon Zeon Co., Ltd. A trade name “Zeonor”, a product name “Arton” manufactured by JSR Corporation, and the like can be given. The norbornene-based monomer constituting the norbornene-based resin is as described above in the section A-2. Examples of the stretching method for satisfying the above optical characteristics include biaxial stretching (longitudinal and transverse equal magnification stretching).

  The thickness of the third optical compensation layer can be set to any appropriate value as long as the desired optical characteristics are obtained. When the third optical compensation layer is a polymer film formed of a cellulose resin, a norbornene resin or the like, the thickness is preferably 45 to 105 μm, more preferably 55 to 95 μm, and particularly preferably 50 to 90 μm.

  Another specific example of the third optical compensation layer includes a laminate having the cholesteric alignment solidified layer and a plastic film layer. Examples of the resin forming the plastic film layer include cellulose resins and norbornene resins. These resins are as described above in this section.

  Any appropriate method can be adopted as a method of laminating the cholesteric alignment solidified layer and the plastic film layer. Specifically, a method of transferring the cholesteric alignment solidified layer to the plastic layer, a method of pasting the cholesteric alignment solidified layer previously formed on the base material and the plastic film layer through an adhesive layer, and the like can be mentioned. The thickness of the adhesive layer is preferably 1 μm to 10 μm, more preferably 1 μm to 5 μm.

[A-5. Adhesive layer or adhesive layer]
The first optical compensation layer may be provided with an adhesive layer or a pressure-sensitive adhesive layer on at least one surface thereof and adhered to the second optical compensation layer.

  The thickness of the adhesive or pressure-sensitive adhesive can be appropriately determined according to the purpose of use or adhesive force, and is generally 1 to 500 μm, preferably 1 to 50 μm, and particularly preferably 3 to 25 μm.

  Any appropriate adhesive or pressure-sensitive adhesive may be adopted as the adhesive or pressure-sensitive adhesive forming the adhesive layer or pressure-sensitive adhesive layer. For example, acrylic polymer, silicone polymer, polyester, polyurethane, polyamide, polyvinyl ether, vinyl acetate / vinyl chloride copolymer, modified polyolefin, epoxy-based, fluorine-based, natural rubber, synthetic rubber-based polymer A polymer can be appropriately selected and used. In particular, an acrylic pressure-sensitive adhesive is preferably used in that it is excellent in optical transparency, exhibits appropriate wettability, cohesiveness, and adhesive pressure-sensitive adhesive properties, and is excellent in weather resistance and heat resistance.

  A curable adhesive may be used. Typical examples of the curable adhesive include a photocurable adhesive such as an ultraviolet curable adhesive, a moisture curable adhesive, and a thermosetting adhesive. Specific examples of the thermosetting adhesive include thermosetting resin adhesives such as epoxy resins, isocyanate resins, and polyimide resins. Specific examples of the moisture curable adhesive include isocyanate resin-based moisture curable adhesive. A moisture curable adhesive (especially an isocyanate resin-based moisture curable adhesive) is preferred. Moisture curable adhesives cure by reacting with moisture in the air, adsorbed water on the surface of the adherend, active hydrogen groups such as hydroxyl groups and carboxyl groups, and so on. It can be cured and has excellent operability. Furthermore, there is no need for high temperature heating for curing. As a result, since there is no fear of heat shrinkage, even when the optical compensation layer is thin, cracks during lamination can be prevented. In addition, the curable adhesive hardly stretches even when heated after curing. Therefore, even when the optical compensation layer is thin and the obtained liquid crystal panel is used under high temperature conditions, cracking of the optical compensation layer can be prevented. The isocyanate resin adhesive is a general term for polyisocyanate resin adhesives and polyurethane resin adhesives.

  As the curable adhesive, for example, a commercially available adhesive may be used, or the above various curable resins may be dissolved or dispersed in a solvent to prepare a curable resin adhesive solution (or dispersion). Good. When preparing a solution (or dispersion liquid), the content of the curable resin in the solution is preferably 10 to 80% by weight, more preferably 20 to 65% by weight, and particularly preferably the solid content weight. It is 25 to 65% by weight, and most preferably 30 to 50% by weight. As a solvent to be used, any appropriate solvent can be adopted depending on the type of curable resin. Specific examples include ethyl acetate, methyl ethyl ketone, methyl isobutyl ketone, toluene, xylene and the like. These may use only 1 type and may use 2 or more types together.

The coating amount of the adhesive can be appropriately set according to the purpose. For example, the coating amount is preferably 0.3 to 3 ml, more preferably 0.5 to ² ml, and most preferably 1 to ² ml per area (cm ² ) of the optical compensation layer.

  After coating, the solvent contained in the adhesive is volatilized by natural drying or heat drying as necessary. The thickness of the adhesive layer thus obtained is preferably 0.1 μm to 20 μm, more preferably 0.5 μm to 15 μm, and most preferably 1 μm to 10 μm.

  The indentation hardness (Microhardness) of the adhesive layer is preferably 0.1 to 0.5 GPa, more preferably 0.2 to 0.5 GPa, and most preferably 0.3 to 0.4 GPa. In addition, since the indentation hardness has a known correlation with Vickers hardness, it can also be converted into Vickers hardness. The indentation hardness can be calculated from the indentation depth and the indentation load using, for example, a thin film hardness meter (for example, trade name MH4000, trade name MHA-400) manufactured by NEC Corporation.

  The formation method of the said adhesive bond layer is suitably selected according to the objective. For example, the curing temperature of the adhesive is appropriately set according to the adhesive used. Preferably it is 30-90 degreeC, More preferably, it is 40-60 degreeC. By curing in these temperature ranges, foaming can be prevented from occurring in the adhesive layer. Furthermore, rapid curing can be prevented. The curing time is appropriately set according to the adhesive used, the curing temperature, and the like. Preferably it is 5 hours or more, More preferably, it is about 10 hours. By forming the adhesive layer under these conditions, an adhesive layer that is easy to handle can be obtained.

[A-6. Polarizer]
Any appropriate polarizer may be adopted as the polarizer depending on the purpose. For example, dichroic substances such as iodine and dichroic dyes are adsorbed on hydrophilic polymer films such as polyvinyl alcohol films, partially formalized polyvinyl alcohol films, and ethylene / vinyl acetate copolymer partially saponified films. And polyene-based oriented films such as a uniaxially stretched product, a polyvinyl alcohol dehydrated product and a polyvinyl chloride dehydrochlorinated product. Among these, a polarizer obtained by adsorbing a dichroic substance such as iodine on a polyvinyl alcohol film and uniaxially stretching is particularly preferable because of its high polarization dichroic ratio. The thickness of these polarizers is not particularly limited, but is generally about 1 to 80 μm.

  A polarizer uniaxially stretched by adsorbing iodine to a polyvinyl alcohol film can be produced, for example, by dyeing polyvinyl alcohol in an aqueous solution of iodine and stretching it 3 to 7 times the original length. . If necessary, it may contain boric acid, zinc sulfate, zinc chloride, or the like, or may be immersed in an aqueous solution such as potassium iodide. Further, if necessary, the polyvinyl alcohol film may be immersed in water and washed before dyeing.

  By washing the polyvinyl alcohol film with water, not only can the surface of the polyvinyl alcohol film be cleaned and the anti-blocking agent can be washed, but also the effect of preventing unevenness such as uneven dyeing can be obtained by swelling the polyvinyl alcohol film. is there. Stretching may be performed after dyeing with iodine, may be performed while dyeing, or may be dyed with iodine after stretching. The film can be stretched in an aqueous solution of boric acid or potassium iodide or in a water bath.

[A-7. Protective layer]
In the laminated optical film of the present invention, a protective layer may be provided on at least one surface of the polarizer. A protective layer consists of arbitrary appropriate films which can be used as a protective film of a polarizing plate. Specific examples of the material that is the main component of such a film include cellulose resins such as triacetylcellulose (TAC), polyester-based, polyvinyl alcohol-based, polycarbonate-based, polyamide-based, polyimide-based, polyethersulfone-based, Examples thereof include transparent resins such as polysulfone, polystyrene, polynorbornene, polyolefin, (meth) acryl, and acetate. Further, thermosetting resins such as (meth) acrylic, urethane-based, (meth) acrylurethane-based, epoxy-based, and silicone-based or ultraviolet curable resins are also included. In addition to this, for example, a glassy polymer such as a siloxane polymer is also included. Moreover, the polymer film as described in Unexamined-Japanese-Patent No. 2001-343529 (WO01 / 37007) can also be used. As a material for this film, for example, 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 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 mentioned. The polymer film can be, for example, an extruded product of the resin composition.

  As said (meth) acrylic-type resin, Tg (glass transition temperature) becomes like this. Preferably it is 115 degreeC or more, More preferably, it is 120 degreeC or more, More preferably, it is 125 degreeC or more, Most preferably, it is 130 degreeC or more. It is because it can be excellent in durability. Although the upper limit of Tg of the said (meth) acrylic-type resin is not specifically limited, From viewpoints of a moldability etc., Preferably it is 170 degrees C or less.

As said (meth) acrylic-type resin, arbitrary appropriate (meth) acrylic-type resins can be employ | adopted within the range which does not impair the effect of this invention. For example, poly (meth) acrylic acid ester such as polymethyl methacrylate, methyl methacrylate- (meth) acrylic acid copolymer, methyl methacrylate- (meth) acrylic acid ester copolymer, methyl methacrylate-acrylic acid ester -(Meth) acrylic acid copolymer, (meth) acrylic acid methyl-styrene copolymer (MS resin, etc.), polymer having an alicyclic hydrocarbon group (for example, methyl methacrylate-cyclohexyl methacrylate copolymer) And methyl methacrylate- (meth) acrylate norbornyl copolymer). Preferably, poly (meth) acrylic acid C _1-6 alkyl such as poly (meth) acrylate methyl is used. More preferably, a methyl methacrylate resin containing methyl methacrylate as a main component (50 to 100% by weight, preferably 70 to 100% by weight) is used.

  Specific examples of the (meth) acrylic resin include (meth) acrylic resins having a ring structure in the molecule described in, for example, Acrypet VH and Acrypet VRL20A manufactured by Mitsubishi Rayon Co., Ltd., and JP-A-2004-70296. Examples of the resin include high Tg (meth) acrylic resins obtained by intramolecular crosslinking or intramolecular cyclization reaction.

  As the (meth) acrylic resin, a (meth) acrylic resin having a lactone ring structure may be used in that it has high heat resistance, high transparency, and high mechanical strength.

  Examples of the (meth) acrylic resin having the lactone ring structure include JP 2000-230016, JP 2001-151814, JP 2002-120326, JP 2002-254544, and JP 2005. Examples thereof include (meth) acrylic resins having a lactone ring structure described in JP-A-146084.

  The (meth) acrylic resin having the lactone ring structure has a mass average molecular weight (sometimes referred to as a weight average molecular weight) of preferably 1,000 to 2,000,000, more preferably 5,000 to 1,000,000, and still more preferably 10,000 to 500,000. Preferably it is 50000-500000.

  The (meth) acrylic resin having a lactone ring structure has a Tg (glass transition temperature) of preferably 115 ° C. or higher, more preferably 125 ° C. or higher, still more preferably 130 ° C. or higher, particularly preferably 135 ° C., most preferably. Is 140 ° C. or higher. It is because it can be excellent in durability. Although the upper limit of Tg of the (meth) acrylic resin having the lactone ring structure is not particularly limited, it is preferably 170 ° C. or less from the viewpoint of moldability and the like.

  In the present specification, “(meth) acrylic” refers to acrylic and / or methacrylic.

  The protective layer is preferably transparent and has no color. The thickness direction retardation Rth [550] of the protective layer is preferably −20 nm to +20 nm, more preferably −10 nm to +10 nm, still more preferably −6 to +6 nm, and particularly preferably −3 to +3 nm. The in-plane retardation Re [550] of the protective layer is preferably 0 to 10 nm, more preferably 0 to 6 nm, and still more preferably 0 to 3 nm.

  As the thickness of the protective layer, any appropriate thickness can be adopted as long as the preferable retardation Rth in the thickness direction can be obtained. The thickness of the protective layer is typically 5 mm or less, preferably 1 mm or less, more preferably 1 to 500 μm, and particularly preferably 5 to 100 μm.

  On the side of the protective layer opposite to the polarizer, a hard coat treatment, an antireflection treatment, an antisticking treatment, an antiglare treatment, or the like can be performed as necessary.

  As the protective layer, for example, a cellulose film is used. As described above, in the case of a cellulose film generally used as a protective film, for example, a triacetyl cellulose film, the thickness direction retardation Rth is about 40 nm at a thickness of 40 μm. Therefore, a protective layer satisfying the above optical characteristics can be obtained by subjecting the cellulose film having a large thickness direction retardation Rth to an appropriate treatment for reducing the thickness direction retardation Rth.

  Any appropriate treatment method can be adopted as the treatment for reducing the retardation Rth in the thickness direction. For example, a base material such as polyethylene terephthalate, polypropylene, and stainless steel coated with a solvent such as cyclopentanone and methyl ethyl ketone is bonded to a general cellulose film and dried by heating (for example, about 80 to 150 ° C. for 3 to 10 minutes) After removing the base film, a solution obtained by dissolving norbornene resin, acrylic resin or the like in a solvent such as cyclopentanone or methyl ethyl ketone is applied to a general cellulose film and dried by heating (for example, And a method of peeling the coated film after about 3 to 10 minutes at about 80 to 150 ° C.).

  The material constituting the cellulose film is preferably a fatty acid-substituted cellulose polymer such as diacetyl cellulose or triacetyl cellulose. Generally used triacetyl cellulose has an acetic acid substitution degree of about 2.8, preferably an acetic acid substitution degree of 1.8 to 2.7, more preferably a propionic acid substitution degree of 0.1 to 2.7. By controlling to 1, the thickness direction retardation (Rth) can be controlled to be small.

  By adding a plasticizer such as dibutyl phthalate, p-toluenesulfonanilide, acetyltriethyl citrate to the fatty acid-substituted cellulose polymer, the thickness direction retardation Rth can be controlled to be small.

  The addition amount of the plasticizer is preferably 40 parts by weight or less, more preferably 1 to 20 parts by weight, and still more preferably 1 to 15 parts by weight with respect to 100 parts by weight of the fatty acid-substituted cellulose polymer.

  The techniques for controlling the thickness direction retardation Rth as described above may be used in appropriate combination.

[A-8. Other components]
The laminated optical film in the present invention may further include another optical layer. As such another optical layer, any appropriate optical layer may be employed depending on the purpose and the type of the image display device. Specific examples include a liquid crystal film, a light scattering film, a diffraction film, and another optical compensation layer (retardation film).

  The laminated optical film in the present invention may further have a pressure-sensitive adhesive layer or an adhesive layer as an outermost layer on at least one side. Thus, by having a pressure-sensitive adhesive layer or an adhesive layer as the outermost layer, for example, lamination with another member (for example, a liquid crystal cell) is facilitated, and the polarizing plate can be prevented from peeling from the other member. . Any appropriate material can be adopted as the material of the pressure-sensitive adhesive layer. Specific examples of the pressure-sensitive adhesive include those described above. Specific examples of the adhesive include those described above. Preferably, a material excellent in hygroscopicity and heat resistance is used. This is because foaming and peeling due to moisture absorption, deterioration of optical characteristics due to a difference in thermal expansion, and warpage of the liquid crystal cell can be prevented.

  Practically, the surface of the pressure-sensitive adhesive layer or adhesive layer is covered with any appropriate separator until the polarizing plate is actually used, and contamination can be prevented. The separator can be formed by, for example, a method of providing a release coat with a release agent such as silicone-based, long-chain alkyl-based, fluorine-based, molybdenum sulfide, or the like on any appropriate film as necessary.

  Each layer in the laminated optical film of the present invention imparts ultraviolet absorbing ability by, for example, treatment with an ultraviolet absorber such as a salicylic acid ester compound, a benzophenone compound, a benzotriazole compound, a cyanoacrylate compound, a nickel complex compound, or the like. It may be what you did.

[B. Manufacturing method of laminated optical film]
Arbitrary appropriate methods may be employ | adopted for the manufacturing method of the laminated optical film in this invention in the range which does not impair the effect of this invention. Below, an example of the specific procedure of the manufacturing method of the laminated optical film in this invention is demonstrated. Note that the manufacturing method is not limited to this method.

  The polarizers can be laminated at any appropriate time in the production method of the present invention. For example, the polarizer may be stacked after the first optical compensation layer and the second optical compensation layer are bonded together.

  Any appropriate lamination method (for example, adhesion) can be adopted as a method for laminating the polarizer. Adhesion can be performed using any suitable adhesive or adhesive. The type of adhesive or pressure-sensitive adhesive can be appropriately selected according to the type of adherend. The thickness of the adhesive or pressure-sensitive adhesive is preferably 10 to 200 nm, more preferably 30 to 180 nm, and most preferably 50 to 150 nm.

  Below, an example of the manufacturing method of the laminated optical film of this invention is demonstrated.

  The first optical compensation layer is laminated on the second optical compensation layer via an adhesive layer or an adhesive layer. Examples of the pressure-sensitive adhesive layer and adhesive layer that can be used at this time include those described above.

  Next, a polarizer is laminated on the obtained laminate of the first optical compensation layer and the second optical compensation layer via an adhesive layer or an adhesive layer. Examples of the pressure-sensitive adhesive layer and adhesive layer that can be used at this time include those described above. The polarizer may be one in which a protective layer is previously laminated on the polarizer.

  In the present invention, it is important that the polarizers and the first optical compensation layer are laminated in the same direction so that the angle formed by the optical axes is within a desired range. That is, the slow axis direction of the first optical compensation layer is arranged so as to be substantially parallel or substantially orthogonal to the absorption axis direction of the polarizer.

  In the present invention, it is preferable that the polarizers and the second optical compensation layer are laminated in the same direction so that the angle formed by the optical axes is within a desired range. That is, it is preferable that the slow axis direction of the second optical compensation layer is arranged so as not to be substantially parallel to or substantially perpendicular to the absorption axis direction of the polarizer.

[C. Application of laminated optical film]
The laminated optical film in the present invention can be suitably used for various image display devices (for example, liquid crystal display devices, self-luminous display devices). Specific examples of the applicable image display device include a liquid crystal display device, an EL display, a plasma display (PD), and a field emission display (FED). When the laminated optical film of the present invention is used for a liquid crystal display device, it is useful for preventing light leakage and viewing angle compensation in black display, for example. The laminated optical film in the present invention is suitably used for a VA mode liquid crystal display device, and is particularly suitably used for a reflective and transflective VA mode liquid crystal display device. Moreover, when using the laminated | multilayer optical film in this invention for EL display, it is useful for electrode reflection prevention, for example.

[D. LCD panel]
The liquid crystal panel of the present invention includes the laminated optical film of the present invention and a liquid crystal cell. FIG. 4 is a schematic cross-sectional view of a liquid crystal panel according to a preferred embodiment of the present invention. For the sake of clarity, it should be noted that the vertical, horizontal, and thickness ratios of the constituent members in the figure are different from the actual ratios. The liquid crystal panel 100 includes at least a liquid crystal cell 1, a laminated optical film 10 disposed on one side of the liquid crystal cell 1, and an arbitrary circularly polarizing plate 60 disposed on the other side of the liquid crystal cell 1. In the illustrated example, the laminated optical film 10 shows a liquid crystal panel having a configuration arranged below the liquid crystal cell. This liquid crystal panel has a configuration in which the liquid crystal panel of FIG. There may be.

  The liquid crystal cell preferably includes liquid crystal molecules aligned in a homeotropic alignment. In this specification, “homeotropic alignment” means a state in which the alignment vector of liquid crystal molecules is aligned perpendicularly (in the normal direction) to the substrate plane as a result of the interaction between the alignment-treated substrate and the liquid crystal molecules. Refers to things. The refractive index ellipsoid of such a liquid crystal cell shows a relationship of nz> nx = ny. The homeotropic alignment includes a case where the alignment vector of the liquid crystal molecules is slightly inclined with respect to the normal direction of the substrate, that is, the case where the liquid crystal molecules have a pretilt. When the liquid crystal molecules have a pretilt, the pretilt angle (angle from the substrate normal) is preferably 5 ° or less. By setting the pretilt angle in the above range, a liquid crystal display device with a high contrast ratio can be obtained.

  Examples of the liquid crystal cell in which the refractive index ellipsoid shows a relationship of nz> nx = ny include a vertical alignment (VA) mode and a vertically aligned ECB (Electrically Controlled Birefringence) mode according to the classification according to the drive mode.

Rth _LC [590] of the above liquid crystal cell in the absence of an electric field is preferably −500 nm to −200 nm, more preferably −400 nm to −200 nm. The Rth _LC [590] is appropriately set depending on the birefringence of the liquid crystal molecules and the cell gap. The cell gap (substrate interval) of the liquid crystal cell is usually 1.0 μm to 7.0 μm.

[E. Liquid crystal display device]
The liquid crystal display device of the present invention includes the liquid crystal panel of the present invention. FIG. 5 is a schematic cross-sectional view of a liquid crystal display device according to a preferred embodiment of the present invention. For the sake of clarity, it should be noted that the vertical, horizontal, and thickness ratios of the constituent members in the figure are different from the actual ratios. The liquid crystal display device 200 includes at least a liquid crystal panel 100 and a backlight unit 80 disposed on one side of the liquid crystal panel 100. In the illustrated example, the case where the direct type is adopted as the backlight unit is shown, but this may be a side light type, for example.

  When the direct type is adopted, the backlight unit 80 preferably includes at least a light source 81, a reflection film 82, a diffusion plate 83, a prism sheet 84, and a brightness enhancement film 85. When the sidelight method is adopted, preferably, the backlight unit further includes at least a light guide plate and a light reflector in addition to the above-described configuration. In addition, as long as the effect of the present invention is obtained, a part of the optical member illustrated in FIG. 5 can be omitted depending on the application, such as the illumination method of the liquid crystal display device and the driving mode of the liquid crystal cell, or Other optical members can be substituted.

  The liquid crystal display device may be a transmissive type that irradiates light from the back side of the liquid crystal panel to view the screen, or a reflective type that irradiates light from the viewing side of the liquid crystal panel to view the screen. good. Alternatively, the liquid crystal display device may be a transflective type having both transmissive and reflective properties.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited by these Examples. In addition, the sign of the shaft angle referred to in the following examples and comparative examples is negative (-) for counterclockwise when viewed from the backlight side and positive (+) for clockwise when the liquid crystal panel is configured. .

(1) Measurement of phase difference value, Nz coefficient, and transmittance T Automatic measurement was performed using a trade name: KOBRA-WPR manufactured by Oji Scientific Instruments. The measurement temperature was 23 ° C. In addition, the value measured using the Abbe refractometer [Atago Co., Ltd. product name "DR-M4"] was used for the average refractive index.

(2) Measurement of thickness When the thickness was less than 10 μm, the thickness was measured using a spectrophotometer for thin film [manufactured by Otsuka Electronics Co., Ltd., “instant multiphotometry system MCPD-2000”]. When the thickness was 10 μm or more, measurement was performed using an Anritsu digital micrometer “KC-351C type”.

(3) Viewing angle characteristic About the VA mode liquid crystal cell with which the laminated optical film was mounted, the viewing angle characteristic was measured using the viewing angle characteristic measuring apparatus (ELDIM company make, EZ Contrast). Further, viewing angle characteristics were measured by computer simulation using a simulator for liquid crystal display “LCD MASTER” manufactured by Shintech.

[Production Example 1]: Production of Polarizing Plate After a polyvinyl alcohol film is dyed in an aqueous solution containing iodine, it is uniaxially stretched 6 times between rolls having different speed ratios in an aqueous solution containing boric acid to obtain a polarizer. Obtained. A triacetyl cellulose film (thickness 40 μm) [manufactured by Konica Minolta, product name: KC4UYW] as a protective layer was attached to both sides of the thus obtained polarizer via a polyvinyl alcohol-based adhesive (thickness 0.1 μm). . The in-plane retardation Re of the protective layer was 0.9 nm, and the thickness direction retardation Rth was 1.2 nm. In this way, a polarizing plate was obtained.

[Production Example 2]: Production of first optical compensation layer A biaxially stretched polypropylene film [trade name “Torphan BO24-100” (thickness: 60 μm) manufactured by Toray Industries, Inc.] on both sides of a polycarbonate resin film having a thickness of 100 μm was acrylic. It bonded together through the system adhesive layer (thickness 15 micrometers). Then, the film is held in the longitudinal direction with a roll stretching machine, and stretched 1.32 times in a 150 ° C air circulation thermostatic oven (measured at a distance of 3 cm from the film backside / temperature variation ± 1 ° C). Thus, a stretched film (thickness 55 μm) was obtained. The obtained stretched film had an in-plane retardation Re ₁ of 270 nm, a thickness direction retardation Rth ₁ of 135 nm, and an Nz coefficient (Rth ₁ / Re ₁ ) of 0.5. The polycarbonate resin film had a glass transition temperature (Tg) of 136 ° C., an in-plane retardation before stretching of 5 nm, and a retardation in the thickness direction of 12 nm.

[Production Example 3]: Production of second optical compensation layer A long norbornene-based resin film (manufactured by Nippon Zeon Co., Ltd., trade name: Zeonor, thickness 60 μm) is biaxially stretched at 150 ° C. to 1.55 times. Thus, a long film was produced. The in-plane retardation Re of this film was 140 nm, the thickness direction retardation Rth was 217 nm, and the Nz coefficient (Rth / Re) was 1.55.

[Production Example 4]: Preparation of third optical compensation layer 90 parts by weight of a nematic liquid crystalline compound represented by the following chemical formula (1), 10 parts by weight of a chiral agent represented by the following chemical formula (2), a photopolymerization initiator (Irgacure 907: Ciba Specialty Chemicals) 5 parts by weight and 300 parts by weight of methyl ethyl ketone were mixed uniformly to prepare a liquid crystal coating solution. Next, this liquid crystal coating solution is coated on a substrate (biaxially stretched PET film), heat-treated at 80 ° C. for 3 minutes, and then subjected to polymerization treatment by irradiating with ultraviolet rays, and a third optical compensation layer and A cholesteric alignment solidified layer was formed. The thickness of the cholesteric alignment fixed layer was 1.8 μm, the thickness direction retardation Rth ₃ was 90 nm, and the in-plane retardation Re ₃ was substantially zero.

[Example 1]

(Preparation of laminated optical film (1-A))
The polarizing plate obtained above, the first optical compensation layer, and the second optical compensation layer were laminated in this order. Here, the first optical compensation layer and the second optical compensation layer were laminated so that the slow axes were 0 ° and −45 ° with respect to the absorption axis of the polarizer of the polarizing plate, respectively. Each layer was laminated via an acrylic pressure-sensitive adhesive (thickness: 12 μm). In this way, a laminated optical film (1-A) was obtained.

(Preparation of laminated optical film (1-B))
The polarizing plate and the second optical compensation layer obtained above were laminated in this order. Here, the second optical compensation layer was laminated so that the slow axis was −45 ° with respect to the absorption axis of the polarizer of the polarizing plate. Each layer was laminated via an acrylic pressure-sensitive adhesive (thickness: 12 μm). In this way, a laminated optical film (1-B) was obtained.

(Production of liquid crystal panel)
The liquid crystal cell was removed from the Sony PlayStation Portable (VA mode liquid crystal cell mounted), and the laminated film (1-A) was attached to the viewing side of the liquid crystal cell via an acrylic adhesive (thickness 20 μm). At that time, each optical compensation layer was attached so as to be on the liquid crystal cell side. Moreover, the said laminated | multilayer film (1-B) was affixed on the backlight side of the liquid crystal cell through the acrylic adhesive (thickness 20 micrometers). At that time, each optical compensation layer was attached so as to be on the liquid crystal cell side. Moreover, it laminated | stacked so that the absorption axis of the polarizer of laminated | multilayer film (1-A) and the absorption axis of laminated | multilayer optical film (1-B) might mutually cross substantially orthogonally, and obtained liquid crystal panel (1).
Computer simulation was performed on the viewing angle dependence of the contrast of the liquid crystal display device using the liquid crystal panel (1). The results are shown in FIG.

[Example 2]

(Preparation of laminated optical film (2-A))
The polarizing plate obtained above, the first optical compensation layer, and the second optical compensation layer were laminated in this order. Here, the first optical compensation layer and the second optical compensation layer were laminated so that the slow axes were 90 ° and −45 ° with respect to the absorption axis of the polarizer of the polarizing plate, respectively. Each layer was laminated via an acrylic pressure-sensitive adhesive (thickness: 12 μm). In this way, a laminated optical film (2-A) was obtained.

(Preparation of laminated optical film (2-B))
The laminated optical film (1-B) obtained in Example 1 was directly used as the laminated optical film (2-B).

(Production of liquid crystal panel)
Example 1 except that the laminated optical film (2-A) was used instead of the laminated optical film (1-A), and the laminated optical film (2-B) was used instead of the laminated optical film (1-B). Then, a liquid crystal panel (2) was obtained.
Computer simulation was performed on the viewing angle dependence of the contrast of the liquid crystal display device using the liquid crystal panel (2). The results are shown in FIG.

[Comparative Example 1]

(Preparation of laminated optical film (C1-A))
The laminated optical film (1-B) obtained in Example 1 was directly used as the laminated optical film (C1-A).

(Preparation of laminated optical film (C1-B))
The laminated optical film (1-B) obtained in Example 1 was directly used as the laminated optical film (C1-B).

(Production of liquid crystal panel)
Example 1 except that a laminated optical film (C1-A) was used instead of the laminated optical film (1-A), and a laminated optical film (C1-B) was used instead of the laminated optical film (1-B). In the same manner as above, a liquid crystal panel (C1) was obtained.
Computer simulation was performed on the viewing angle dependence of the contrast of the liquid crystal display device using the liquid crystal panel (C1). The results are shown in FIG.

Example 3

(Preparation of laminated optical film (3-A))
A cholesteric alignment solidified layer as a third optical compensation layer is adhered to the second optical compensation layer obtained above with an isocyanate-based adhesive (thickness 5 μm), and the substrate (biaxially stretched PET film) is removed. Thus, a laminate in which the cholesteric alignment solidified layer was transferred to the second optical compensation layer was obtained. The first optical compensation layer and the polarizing plate obtained above were laminated in this order via an acrylic pressure-sensitive adhesive (thickness: 12 μm) on the second optical compensation layer side of the laminate. Here, the first optical compensation layer and the second optical compensation layer were laminated so that the slow axes were 0 ° and −45 ° with respect to the absorption axis of the polarizer of the polarizing plate, respectively. In this way, a laminated optical film (3-A) was obtained.

(Preparation of laminated optical film (3-B))
The laminated optical film (1-B) obtained in Example 1 was directly used as the laminated optical film (3-B).

(Production of liquid crystal panel)
Example 1 except that the laminated optical film (3-A) was used instead of the laminated optical film (1-A), and the laminated optical film (3-B) was used instead of the laminated optical film (1-B). In the same manner as above, a liquid crystal panel (3) was obtained.
Computer simulation was performed on the viewing angle dependence of the contrast of the liquid crystal display device using the liquid crystal panel (3). The results are shown in FIG.

Example 4

(Preparation of laminated optical film (4-A))
A cholesteric alignment solidified layer as a third optical compensation layer is adhered to the second optical compensation layer obtained above with an isocyanate-based adhesive (thickness 5 μm), and the substrate (biaxially stretched PET film) is removed. Thus, a laminate in which the cholesteric alignment solidified layer was transferred to the second optical compensation layer was obtained. The first optical compensation layer and the polarizing plate obtained above were laminated in this order via an acrylic pressure-sensitive adhesive (thickness: 12 μm) on the second optical compensation layer side of the laminate. Here, the first optical compensation layer and the second optical compensation layer were laminated so that the slow axes were −90 ° and −45 ° with respect to the absorption axis of the polarizer of the polarizing plate, respectively. In this way, a laminated optical film (4-A) was obtained.

(Preparation of laminated optical film (4-B))
The laminated optical film (1-B) obtained in Example 1 was directly used as the laminated optical film (4-B).

(Production of liquid crystal panel)
Example 1 except that the laminated optical film (4-A) was used instead of the laminated optical film (1-A), and the laminated optical film (4-B) was used instead of the laminated optical film (1-B). Then, a liquid crystal panel (4) was obtained.
Computer simulation was performed on the viewing angle dependency of contrast of a liquid crystal display device using the liquid crystal panel (4). The results are shown in FIG.

[Comparative Example 2]

(Preparation of laminated optical film (C2-A))
A cholesteric alignment solidified layer as a third optical compensation layer is adhered to the second optical compensation layer obtained above with an isocyanate-based adhesive (thickness 5 μm), and the substrate (biaxially stretched PET film) is removed. Thus, a laminate in which the cholesteric alignment solidified layer was transferred to the second optical compensation layer was obtained. The first optical compensation layer and the polarizing plate obtained above were laminated in this order via an acrylic pressure-sensitive adhesive (thickness: 12 μm) on the second optical compensation layer side of the laminate. Here, the first optical compensation layer and the second optical compensation layer were laminated so that the slow axes were 5 ° and −45 ° with respect to the absorption axis of the polarizer of the polarizing plate, respectively. In this way, a laminated optical film (C2-A) was obtained.

(Preparation of laminated optical film (C2-B))
The laminated optical film (1-B) obtained in Example 1 was directly used as the laminated optical film (C2-B).

(Production of liquid crystal panel)
Example 1 except that the laminated optical film (C2-A) was used instead of the laminated optical film (1-A), and the laminated optical film (C2-B) was used instead of the laminated optical film (1-B). In the same manner as above, a liquid crystal panel (C2) was obtained.
Computer simulation was performed on the viewing angle dependence of contrast of a liquid crystal display device using the liquid crystal panel (C2). The results are shown in FIG.

[Comparative Example 3]

(Preparation of laminated optical film (C3-A))
A cholesteric alignment solidified layer as a third optical compensation layer is adhered to the second optical compensation layer obtained above with an isocyanate-based adhesive (thickness 5 μm), and the substrate (biaxially stretched PET film) is removed. Thus, a laminate in which the cholesteric alignment solidified layer was transferred to the second optical compensation layer was obtained. The first optical compensation layer and the polarizing plate obtained above were laminated in this order via an acrylic pressure-sensitive adhesive (thickness: 12 μm) on the second optical compensation layer side of the laminate. Here, the first optical compensation layer and the second optical compensation layer were laminated so that the slow axes were 30 ° and −45 ° with respect to the absorption axis of the polarizer of the polarizing plate, respectively. In this way, a laminated optical film (C3-A) was obtained.

(Preparation of laminated optical film (C3-B))
The laminated optical film (1-B) obtained in Example 1 was directly used as the laminated optical film (C3-B).

(Production of liquid crystal panel)
Example 1 except that a laminated optical film (C3-A) was used instead of the laminated optical film (1-A), and a laminated optical film (C3-B) was used instead of the laminated optical film (1-B). Then, a liquid crystal panel (C3) was obtained.
Computer simulation was performed on the viewing angle dependency of contrast of a liquid crystal display device using the liquid crystal panel (C3). The results are shown in FIG.

[Comparative Example 4]

(Preparation of laminated optical film (C4-A))
A cholesteric alignment solidified layer as a third optical compensation layer is adhered to the second optical compensation layer obtained above with an isocyanate-based adhesive (thickness 5 μm), and the substrate (biaxially stretched PET film) is removed. Thus, a laminate in which the cholesteric alignment solidified layer was transferred to the second optical compensation layer was obtained. The first optical compensation layer and the polarizing plate obtained above were laminated in this order via an acrylic pressure-sensitive adhesive (thickness: 12 μm) on the second optical compensation layer side of the laminate. Here, the first optical compensation layer and the second optical compensation layer were laminated so that the slow axes were 45 ° and −45 ° with respect to the absorption axis of the polarizer of the polarizing plate, respectively. In this way, a laminated optical film (C4-A) was obtained.

(Preparation of laminated optical film (C4-B))
The laminated optical film (1-B) obtained in Example 1 was directly used as the laminated optical film (C4-B).

(Production of liquid crystal panel)
Example 1 except that a laminated optical film (C4-A) was used instead of the laminated optical film (1-A), and a laminated optical film (C4-B) was used instead of the laminated optical film (1-B). In the same manner as above, a liquid crystal panel (C4) was obtained.
Computer simulation was performed on the viewing angle dependence of the contrast of the liquid crystal display device using the liquid crystal panel (C4). The results are shown in FIG.

[Comparative Example 5]

(Preparation of laminated optical film (C5-A))
A cholesteric alignment solidified layer as a third optical compensation layer is adhered to the second optical compensation layer obtained above with an isocyanate-based adhesive (thickness 5 μm), and the substrate (biaxially stretched PET film) is removed. Thus, a laminate in which the cholesteric alignment solidified layer was transferred to the second optical compensation layer was obtained. The first optical compensation layer and the polarizing plate obtained above were laminated in this order via an acrylic pressure-sensitive adhesive (thickness: 12 μm) on the second optical compensation layer side of the laminate. Here, the first optical compensation layer and the second optical compensation layer were laminated so that the slow axes were 50 ° and −45 ° with respect to the absorption axis of the polarizer of the polarizing plate, respectively. In this way, a laminated optical film (C5-A) was obtained.

(Preparation of laminated optical film (C5-B))
The laminated optical film (1-B) obtained in Example 1 was directly used as a laminated optical film (C5-B).

(Production of liquid crystal panel)
Example 1 except that the laminated optical film (1-A) was used instead of the laminated optical film (C5-A), and the laminated optical film (1-B) was used instead of the laminated optical film (C5-B). Then, a liquid crystal panel (C5) was obtained.
Computer simulation was performed on the viewing angle dependence of the contrast of the liquid crystal display device using the liquid crystal panel (C5). The results are shown in FIG.

[Comparative Example 6]

(Preparation of laminated optical film (C6-A))
A cholesteric alignment solidified layer as a third optical compensation layer is adhered to the second optical compensation layer obtained above with an isocyanate-based adhesive (thickness 5 μm), and the substrate (biaxially stretched PET film) is removed. Thus, a laminate in which the cholesteric alignment solidified layer was transferred to the second optical compensation layer was obtained. The first optical compensation layer and the polarizing plate obtained above were laminated in this order via an acrylic pressure-sensitive adhesive (thickness: 12 μm) on the second optical compensation layer side of the laminate. Here, the first optical compensation layer and the second optical compensation layer were laminated so that the slow axes were 60 ° and −45 ° with respect to the absorption axis of the polarizer of the polarizing plate, respectively. In this way, a laminated optical film (C6-A) was obtained.

(Preparation of laminated optical film (C6-B))
The laminated optical film (1-B) obtained in Example 1 was directly used as a laminated optical film (C6-B).

(Production of liquid crystal panel)
Example 1 except that a laminated optical film (C6-A) was used instead of the laminated optical film (1-A), and a laminated optical film (C6-B) was used instead of the laminated optical film (1-B). In the same manner as above, a liquid crystal panel (C6) was obtained.
Computer simulation was performed on the viewing angle dependency of contrast of a liquid crystal display device using the liquid crystal panel (C6). The results are shown in FIG.

[Evaluation]
6 to 15, it can be seen that the liquid crystal panel using the laminated optical film of the present invention has significantly improved viewing angle characteristics as compared with the liquid crystal panel not using the laminated optical film of the present invention. .

  The laminated optical film of the present invention, and a liquid crystal panel and a liquid crystal display device using the same are used for any appropriate application. Applications include, for example, personal computer monitors, notebook computers, copiers and other office automation equipment, mobile phones, watches, digital cameras, personal digital assistants (PDAs), portable game machines and other portable devices, video cameras, televisions, microwave ovens, etc. Home appliances, back monitors, car navigation system monitors, car audio and other in-vehicle equipment, exhibition equipment such as commercial store information monitors, security equipment such as monitoring monitors, nursing monitors, medical monitors, etc. Nursing care / medical equipment.

It is a schematic sectional drawing of the laminated optical film by preferable embodiment of this invention. It is a schematic diagram which shows the concept of the typical manufacturing process of retardation film (A) used for this invention. It is a schematic perspective view of the laminated optical film in preferable embodiment of this invention. It is a schematic sectional drawing of the liquid crystal panel used for the liquid crystal display device by preferable embodiment of this invention. 1 is a schematic cross-sectional view of a liquid crystal display device according to a preferred embodiment of the present invention. It is a chart figure which shows the result of having measured the viewing angle characteristic of the liquid crystal panel (1) by the computer simulation. It is a chart figure which shows the result of having measured the viewing angle characteristic of the liquid crystal panel (2) by the computer simulation. It is a chart figure which shows the result of having measured the viewing angle characteristic of the liquid crystal panel (C1) by computer simulation. It is a chart figure which shows the result of having measured the viewing angle characteristic of the liquid crystal panel (3) by the computer simulation. It is a chart figure which shows the result of having measured the viewing angle characteristic of the liquid crystal panel (4) by the computer simulation. It is a chart figure which shows the result of having measured the viewing angle characteristic of the liquid crystal panel (C2) by computer simulation. It is a chart figure which shows the result of having measured the viewing angle characteristic of the liquid crystal panel (C3) by the computer simulation. It is a chart figure which shows the result of having measured the viewing angle characteristic of the liquid crystal panel (C4) by computer simulation. It is a chart figure which shows the result of having measured the viewing angle characteristic of the liquid crystal panel (C5) by computer simulation. It is a chart figure which shows the result of having measured the viewing angle characteristic of the liquid crystal panel (C6) by computer simulation.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid crystal cell 10 Laminated optical film 20 Polarizer 30 1st optical compensation layer 40 2nd optical compensation layer 100 Liquid crystal panel 200 Liquid crystal display device

Claims (9)

Having a polarizer, a first optical compensation layer, and a second optical compensation layer in this order;
The first optical compensation layer has a refractive index distribution of nx>nz> ny, and is arranged so that a slow axis direction thereof is substantially parallel or substantially orthogonal to the absorption axis direction of the polarizer. ,
The second optical compensation layer has a refractive index profile of nx>ny>nz;
Laminated optical film.   The laminated optical film according to claim 1, wherein the Nz coefficient of the first optical compensation layer is 0.1 to 0.6.   The laminated optical film according to claim 1 or 2, wherein the first optical compensation layer is composed of a single retardation film (A).   The laminated optical film according to claim 3, wherein the retardation film (A) contains at least one thermoplastic resin selected from norbornene-based resins, cellulose-based resins, carbonate-based resins, and ester-based resins.   The second optical compensation layer is composed of one retardation film (B), and the slow axis direction of the retardation film (B) is substantially 45 ° with respect to the absorption axis direction of the polarizer. The laminated optical film according to claim 1, which is arranged at an angle.   The laminated optical film according to claim 5, wherein the retardation film (B) contains at least one thermoplastic resin selected from norbornene resins and carbonate resins.   The third optical compensation layer having a refractive index profile of nx = ny> nz is disposed on the opposite side of the second optical compensation layer from the first optical compensation layer. The laminated optical film according to any one of the above.   A liquid crystal panel comprising the laminated optical film according to claim 1 and a liquid crystal cell.   A liquid crystal display device comprising the liquid crystal panel according to claim 8.