WO2011162132A1 - Light-diffusing polarization plate and liquid-crystal display device - Google Patents

Light-diffusing polarization plate and liquid-crystal display device Download PDF

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Publication number
WO2011162132A1
WO2011162132A1 PCT/JP2011/063606 JP2011063606W WO2011162132A1 WO 2011162132 A1 WO2011162132 A1 WO 2011162132A1 JP 2011063606 W JP2011063606 W JP 2011063606W WO 2011162132 A1 WO2011162132 A1 WO 2011162132A1
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Prior art keywords
light
film
layer
resin
liquid crystal
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PCT/JP2011/063606
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French (fr)
Japanese (ja)
Inventor
康弘 羽場
誠治 室
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住友化学株式会社
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Publication of WO2011162132A1 publication Critical patent/WO2011162132A1/en

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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/02—Diffusing elements; Afocal elements
    • G02B5/0205—Diffusing elements; Afocal elements characterised by the diffusing properties
    • G02B5/0236—Diffusing elements; Afocal elements characterised by the diffusing properties the diffusion taking place within the volume of the element
    • G02B5/0242—Diffusing elements; Afocal elements characterised by the diffusing properties the diffusion taking place within the volume of the element by means of dispersed particles
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/02—Diffusing elements; Afocal elements
    • G02B5/0205—Diffusing elements; Afocal elements characterised by the diffusing properties
    • G02B5/021—Diffusing elements; Afocal elements characterised by the diffusing properties the diffusion taking place at the element's surface, e.g. by means of surface roughening or microprismatic structures
    • G02B5/0231—Diffusing elements; Afocal elements characterised by the diffusing properties the diffusion taking place at the element's surface, e.g. by means of surface roughening or microprismatic structures the surface having microprismatic or micropyramidal shape

Definitions

  • the present invention relates to a light diffusing polarizing plate and a liquid crystal display device using the same.
  • a liquid crystal display device includes a backlight device and a liquid crystal panel, and the liquid crystal panel is disposed on a liquid crystal cell, a back side polarizing plate disposed on a backlight side of the liquid crystal cell, and a viewing side of the liquid crystal cell.
  • the front side polarizing plate is included.
  • Patent Document 1 discloses a polarizing plate having a relatively high light diffusibility (“second light diffusion layer” in Patent Document 1) on the front side (viewing side) of a liquid crystal cell. Is disclosed).
  • This second light diffusing layer is, for example, a polarizing plate and a resin layer (light diffusing layer) provided on the front side of the polarizing plate and provided with a light diffusing function containing a relatively large amount of filler (light diffusing agent). ).
  • the liquid crystal display device for the purpose of further improving the visibility of the liquid crystal display device, it is possible to prevent or reduce external light from being reflected on the display surface on the outermost surface of the liquid crystal display device, that is, the outermost surface of the front-side polarizing plate.
  • an optical process such as an anti-glare process or an anti-reflection process for preventing or reducing reflection of external light incident on the display surface is performed.
  • the shape of the surface on which the optical treatment is performed needs to be precisely controlled.
  • the light diffusion layer containing a relatively large amount of filler such as the light diffusion layer of the front side polarizing plate described in Patent Document 1
  • an object of the present invention is to provide a new light diffusing polarizing plate which has a sufficient light diffusing property and which also exhibits another optical function and a liquid crystal display device using the same. is there.
  • the present invention includes a polarizing film, a light diffusing film laminated on the polarizing film, and a surface treatment film laminated on the light diffusing film, the light diffusing film having a light diffusing layer, Among the surfaces of the diffusion layer, the center line average roughness Ra of the surface closer to the surface treatment film is 0.1 ⁇ m or more and less than 1 ⁇ m, and the surface treatment film is a transparent resin in which one surface is optically treated.
  • a light diffusing polarizing plate which is formed from a film and in which a light diffusion layer and a surface treatment film are bonded to each other via an adhesive layer or an adhesive layer.
  • the surface treatment film has a surface not subjected to optical treatment, and the light diffusion layer and the surface not subjected to optical treatment of the surface treatment film are adhesive. It is preferable that the light diffusion layer and the surface treatment film are bonded to each other through an agent layer or an adhesive layer.
  • the optical treatment can be, for example, an antiglare treatment or an antireflection treatment.
  • the light diffusing film further includes a transparent base film, and the light diffusing layer is laminated on the transparent base film, and the light diffusing layer is dispersed in the translucent resin and the translucent resin. It is preferable that it contains a light-sensitive fine particle.
  • the light diffusion layer of such a light diffusion film can be formed by applying a resin liquid in which translucent fine particles are dispersed on a transparent substrate film.
  • the light diffusion layer is formed by applying a resin liquid in which translucent fine particles are dispersed on a transparent substrate film, and transferring a mirror surface or an uneven surface of a mold onto the surface of the layer formed from the resin liquid. It may be formed.
  • the present invention also provides a liquid crystal display device comprising a backlight device, a light diffusing means, a backlight side polarizing plate, a liquid crystal cell, and the light diffusing polarizing plate in this order.
  • the light diffusing polarizing plate is disposed so that the polarizing film is closer to the liquid crystal cell than the surface treatment film.
  • the light emitted from the light diffusing means has a light distribution in which the luminance in a direction inclined by 70 ° from the normal direction of the light incident surface of the liquid crystal cell is 20% or less with respect to the luminance in the normal direction. It is preferable that it has characteristics and includes non-parallel light.
  • the light diffusing means can include a light diffusing plate and a light deflecting plate in this order from the backlight device side.
  • a TN (Twisted Nematic) type liquid crystal cell an IPS (In-Plane Switching) type liquid crystal cell, a VA (Vertical Alignment) type liquid crystal cell, or the like can be used.
  • FIG. 1 is a schematic cross-sectional view showing a preferred example of the light diffusing polarizing plate of the present invention.
  • a light diffusing polarizing plate 100 shown in FIG. 1 according to the present invention includes a polarizing film 101, a light diffusing film 102 laminated on the polarizing film 101, and a surface treatment film 103 laminated on the light diffusing film 102.
  • the light diffusing film 102 has a light diffusing layer 106, and the surface-treated film 103 is optically treated on one surface (specifically, a surface-treated layer 108 is provided).
  • the light diffusion layer 106 of the light diffusion film 102 and the surface treatment film 103 are bonded to each other via the pressure-sensitive adhesive layer or the adhesive layer 104.
  • the light diffusing film 102 includes a transparent base film 105 and a light diffusing layer 106 laminated on the transparent base film 105.
  • Reference numeral 106 denotes a resin layer in which translucent fine particles 106b are dispersed in a translucent resin 106a.
  • the light diffusing film 102 is placed on the polarizing film 101 so that the transparent base film 105 side faces the polarizing film 101, that is, the transparent base film 105 is closer to the polarizing film 101 than the light diffusing layer 106. Laminated.
  • the light diffusing film 102 has a center line average roughness Ra according to JIS B 0601 on the surface closer to the surface treatment film 103 of the surface of the light diffusing layer 106 is 0.1 ⁇ m or more and less than 1 ⁇ m.
  • the surface treatment film 103 includes a transparent resin film 107 and a surface treatment layer 108 laminated on one surface of the transparent resin film 107.
  • the surface treatment film 103 is a surface opposite to the surface treatment layer 108 of the transparent resin film 107 (the surface of the surface treatment film 103 that is not subjected to optical treatment), and is a pressure-sensitive adhesive layer or an adhesive layer. It is bonded to the light diffusion layer 106 of the light diffusion film 102 through 104.
  • the protective film 109 is a film for protecting the other surface of the polarizing film 101, it is not necessarily required and may be omitted. Further, instead of the protective film 109, an optical compensation film such as a retardation film (retardation plate) may be bonded.
  • an optical compensation film such as a retardation film (retardation plate) may be bonded.
  • the surface treatment film 103 having a desired optical function is reliably formed on the light diffusion layer 106, and the structure and shape of the surface treatment layer 108 by the surface shape of the light diffusion layer 106 It becomes possible to laminate the film while completely eliminating the influence on the film. Therefore, the light diffusing polarizing plate 100 of the present invention exhibits a predetermined optical function by the surface treatment layer 108 as well as a light diffusing function.
  • polarizing film 101 for example, a dichroic dye or iodine is adsorbed and oriented on a film containing polyvinyl alcohol resin, polyvinyl acetate resin, ethylene / vinyl acetate (EVA) resin, polyamide resin, polyester resin, or the like.
  • a uniaxially stretched polyvinyl alcohol resin film obtained by adsorbing and orienting a dichroic dye or iodine is suitably used as a polarizing film.
  • the thickness of the polarizing film 101 is not particularly limited, but is preferably 100 ⁇ m or less, more preferably 10 to 50 ⁇ m, still more preferably 25 to 35 ⁇ m from the viewpoint of reducing the thickness of the light diffusing polarizing plate.
  • the light diffusion film 102 used in the present invention includes a transparent base film 105 and a light diffusion layer 106 laminated on the transparent base film 105, and the light diffusion layer 106 is translucent. It is preferably composed of a resin layer formed of a resin 106a and translucent fine particles (light diffusing agent) 106b dispersed in the translucent resin 106a.
  • the transparent substrate film 105 is not particularly limited as long as it is optically transparent, and for example, glass or plastic film can be used.
  • the plastic film preferably has moderate transparency and mechanical strength.
  • cellulose acetate resins such as TAC (triacetyl cellulose); acrylic resins; polycarbonate resins; and polyesters such as polyethylene terephthalate Resin; and the like.
  • the thickness of the transparent substrate film 105 is, for example, 10 to 500 ⁇ m, preferably 20 to 300 ⁇ m.
  • the light diffusing layer 106 is a layer having a translucent resin 106a as a base material, and translucent fine particles 106b are dispersed in the translucent resin 106a.
  • the translucent resin 106a is not particularly limited as long as it has translucency.
  • an ionizing radiation curable resin such as an ultraviolet curable resin or an electron beam curable resin or a cured product of a thermosetting resin, A cured product of a thermoplastic resin, a cured product of a metal alkoxide, or the like can be used.
  • ionizing radiation curable resins are preferred because they can impart high hardness and scratch resistance.
  • the translucent resin 106a is formed by curing the resin by irradiation or heating with ionizing radiation.
  • the ionizing radiation curable resin may be synthesized from polyfunctional acrylates such as polyhydric alcohol acrylic acid or methacrylic acid ester; diisocyanate, polyhydric alcohol and acrylic acid or methacrylic acid hydroxy ester, or the like. And polyfunctional urethane acrylates. Besides these, polyether resins having an acrylate functional group; polyester resins; epoxy resins; alkyd resins; spiroacetal resins; polybutadiene resins; polythiol polyene resins;
  • thermosetting resins examples include phenolic resins, urea melamine resins, epoxy resins, unsaturated polyester resins, and silicone resins, in addition to thermosetting urethane resins prepared from acrylic polyols and isocyanate prepolymers.
  • thermoplastic resins include cellulose derivatives such as acetylcellulose, nitrocellulose, acetylbutylcellulose, ethylcellulose, and methylcellulose; vinyl acetate and copolymers thereof, vinyl chloride and copolymers thereof, vinylidene chloride and copolymers thereof, and the like.
  • Acetal resins such as polyvinyl formal and polyvinyl butyral; Acrylic resins and copolymers thereof, Acrylic resins such as methacrylic resins and copolymers; Polystyrene resins; Polyamide resins; Polyester resins; Polycarbonate resins Etc.
  • a silicon oxide matrix made of a silicon alkoxide material can be used. Specifically, it is tetramethoxysilane, tetraethoxysilane, or the like, and can be made into an inorganic or organic-inorganic composite matrix (translucent resin) by hydrolysis or dehydration condensation.
  • a light diffusing agent formed from light-transmitting organic fine particles or inorganic fine particles can be used.
  • Organic polymer balloons and glass hollow beads can also be used.
  • the translucent fine particles 106b may be composed of one kind of fine particles, or may contain two or more kinds of fine particles.
  • the shape of the translucent fine particles 106b may be any shape such as a spherical shape, a flat shape, a plate shape, a needle shape, and an indefinite shape, but a spherical shape or a substantially spherical shape is preferable.
  • the weight average particle diameter of the translucent fine particles 106b is preferably 0.5 to 15 ⁇ m, and more preferably 3 to 8 ⁇ m.
  • the weight average particle diameter of the light transmitting fine particles 106b is less than 0.5 ⁇ m, the light diffusing property of the light diffusing film 102 becomes insufficient.
  • the weight average particle diameter exceeds 15 ⁇ m, the light diffusion film 102 may not obtain sufficient light diffusibility.
  • the ratio of the standard deviation of the particle diameter to the weight average particle diameter (standard deviation / weight average particle diameter) of the light transmitting fine particles 106b is preferably 0.5 or less, and is preferably 0.4 or less. More preferred. When the ratio exceeds 0.5, translucent fine particles having an extremely large particle diameter are included, and as a result, the center line average roughness Ra of the light diffusion layer is 1 ⁇ m or more, which deviates from the preferred range. Sometimes.
  • the weight average particle diameter and the standard deviation of the particle diameter of the translucent fine particles 106b are measured using a Coulter Multisizer (manufactured by Beckman Coulter, Inc.) based on the Coulter principle (pore electrical resistance method).
  • the content of the light-transmitting fine particles 106b in the light diffusion layer 106 is preferably 20 parts by weight or more and 100 parts by weight or less with respect to 100 parts by weight of the light-transmitting resin 106a.
  • the surface treatment film 103 is interposed between the pressure-sensitive adhesive layer or the adhesive layer 104.
  • the surface treatment layer 108 is applied to the light diffusing polarizing plate 100 reliably and easily and without impairing the structure and shape necessary for the surface treatment layer 108 to exhibit a predetermined optical function. can do.
  • the content of the light transmissive fine particles 106b in the light diffusion layer 106 is more preferably 20 parts by weight or more and 70 parts by weight or less, and further preferably 25 parts by weight or more and 60 parts by weight or less with respect to 100 parts by weight of the light transmissive resin 106a.
  • it is particularly preferably 30 parts by weight or more and 55 parts by weight or less.
  • the light diffusing film 102 When the content of the light transmissive fine particles 106b is less than 20 parts by weight with respect to 100 parts by weight of the light transmissive resin, the light diffusing film 102 has insufficient light diffusibility. When a polarizing plate is applied, sufficient wide viewing angle performance is difficult to obtain. Further, when the content of the light transmissive fine particles 106b exceeds 100 parts by weight with respect to 100 parts by weight of the light transmissive resin, the haze of the light diffusing film 102 becomes excessively large, resulting in a decrease in transparency of the light diffusing film 102. However, when a light diffusing polarizing plate is applied to the liquid crystal display device, the front contrast is lowered.
  • the difference in refractive index between the translucent fine particles 106b and the translucent resin 106a is preferably in the range of 0.04 to 0.15.
  • the refractive index difference between the translucent fine particles 106b and the translucent resin 106a within the above range, appropriate internal scattering occurs due to the refractive index difference between the translucent fine particles 106b and the translucent resin 106a.
  • the light diffusion film 102 having a moderately high diffusibility can be obtained.
  • the surface of the light diffusion layer 106 (the surface opposite to the transparent base film 105, that is, the surface closer to the surface treatment film 103 among the surfaces of the light diffusion layer 106) is formed only by the translucent resin 106a. Preferably it is formed. That is, it is preferable that the translucent fine particles 106 b do not protrude from the surface of the light diffusion layer 106 and are completely buried in the light diffusion layer 106. Therefore, the thickness of the light diffusion layer 106 is preferably 1 to 3 times the weight average particle diameter of the translucent fine particles 106b.
  • the thickness of the light diffusing layer 106 is less than 1 times the weight average particle diameter of the light transmissive fine particles 106b, the surface of the light diffusing layer 106 is formed when the light diffusing polarizing plate 100 is applied to the liquid crystal display device. Since it becomes too coarse, problems, such as air bubble biting, may occur during surface treatment film bonding. Further, when the thickness of the light diffusion layer 106 exceeds three times the weight average particle diameter of the translucent fine particles 106b, the thickness of the light diffusion layer 106 becomes too large, and the light diffusion property of the light diffusion film 102 is accordingly increased. As a result, when the light diffusing polarizing plate 100 is applied to the liquid crystal display device, the front contrast may be lowered.
  • the thickness of the light diffusion layer refers to the maximum thickness from the surface of the light diffusion layer 106 closer to the transparent base film 105 to the opposite surface. Therefore, in the light diffusion film 102 of the present invention, the thickest portion corresponding to A shown in FIG. In the portion where the thickness from the surface near the transparent base film 105 to the opposite surface of the light diffusion layer 106 is not the maximum (for example, the concave portion of the film having unevenness), the thickness of the light diffusion layer 106 is transparent. It may not be 1 or more times the weight average particle diameter of the light-sensitive fine particles 106b.
  • the thickness of the light diffusion layer 106 is preferably in the range of 1 to 30 ⁇ m.
  • the thickness of the light diffusion layer 106 is less than 1 ⁇ m, sufficient scratch resistance required for the light diffusion film 102 disposed on the viewing side surface of the liquid crystal display device may not be provided.
  • the thickness exceeds 30 ⁇ m, the amount of curl generated in the produced light diffusing film 102 becomes large, and the handleability in the manufacturing process of the light diffusing polarizing plate 100 is deteriorated.
  • Centerline average roughness Ra according to JIS B 0601 of the surface of the light diffusion layer 106 (the surface opposite to the transparent base film 105, ie, the surface of the light diffusion layer 106 closer to the surface treatment film 103) Is 0.1 ⁇ m or more and less than 1 ⁇ m, preferably 0.2 ⁇ m or more and less than 0.5 ⁇ m.
  • the center line average roughness Ra on the surface of the light diffusion layer 106 is 1 ⁇ m or more, there may be a problem such as air bubble biting when the surface treatment film is bonded.
  • the center line average roughness Ra is 0.1 ⁇ m or more, and further 0.2 ⁇ m or more.
  • the surface treatment layer showing a good optical function can be imparted to the light diffusing polarizing plate.
  • the centerline average roughness Ra means that only the reference length l (el) is extracted from the roughness curve in the direction of the centerline, the x-axis is extracted in the direction of the centerline of the extracted portion,
  • Centerline average roughness Ra is a program software that can calculate Ra based on the above formula (1) using a confocal interference microscope (for example, “PL ⁇ 2300” manufactured by Optical Solution Co., Ltd.) in accordance with JIS B 0601. Can be calculated.
  • the center line average roughness Ra of the surface of the light diffusing layer 106 closer to the surface treatment film 103 is 0.1 ⁇ m or more and less than 1 ⁇ m.
  • the light diffusion layer 106 may not contain the light-transmitting resin 106b or the light-transmitting fine particles 106a.
  • the light diffusion film 102 preferably has a total haze of 30% to 70% and an internal haze of 30% to 70%.
  • the total light transmittance (Tt) is the sum of the parallel light transmittance (Tp) and the diffuse light transmittance (Td) that are transmitted coaxially with the incident light.
  • the total light transmittance (Tt) and the diffused light transmittance (Td) are values measured in accordance with JIS K 7361.
  • the “internal haze” of the light diffusing film 102 is a haze other than the haze (surface haze) due to the surface shape of the light emitting surface side of the surface of the light diffusing layer 106 among all the hazes.
  • the total haze and / or internal haze When the total haze and / or internal haze is less than 30%, the light scattering property is insufficient, and it is difficult to obtain sufficient wide viewing angle performance. Moreover, when the total haze and / or internal haze exceeds 70%, light scattering becomes strong, and when the light diffusing polarizing plate 100 is applied to the liquid crystal display device, the front contrast may be lowered. Further, when the total haze and / or internal haze exceeds 70%, the transparency of the light diffusion film 102 tends to be impaired. More preferably, the total haze and the internal haze are 35% or more and 65% or less, respectively.
  • the total haze, internal haze, and surface haze of the light diffusion film 102 are specifically measured as follows. That is, first, in order to prevent warping of the film, the surface of the transparent base film 105 side is a glass substrate so that the light diffusion film 102 becomes the surface using an optically transparent adhesive. The sample for measurement is produced by pasting together, and the total haze value of the sample for measurement is measured. For the total haze value, the total light transmittance (Tt) and diffuse light transmittance are measured using a haze transmittance meter (for example, a haze meter “HM-150” manufactured by Murakami Color Research Laboratory Co., Ltd.) in accordance with JIS K 7136. The rate (Td) is measured and calculated by the above equation (2).
  • a haze transmittance meter for example, a haze meter “HM-150” manufactured by Murakami Color Research Laboratory Co., Ltd.
  • the light diffusion film 102 may have another layer (including an adhesive layer) between the transparent base film 105 and the light diffusion layer 106.
  • the light diffusion film 102 can be formed by a method including a step of applying a resin liquid in which the translucent fine particles 106b are dispersed on the transparent base film 105.
  • the resin liquid is a translucent fine particle 106b, a translucent resin 106a constituting the light diffusion layer 106, or a resin forming the same (for example, ionizing radiation curable resin, thermosetting resin, thermoplastic resin, or metal alkoxide). And other components such as a solvent as necessary.
  • the resin liquid includes a photopolymerization initiator (radical polymerization initiator).
  • photopolymerization initiator examples include acetophenone photopolymerization initiator, benzoin photopolymerization initiator, benzophenone photopolymerization initiator, thioxanthone photopolymerization initiator, triazine photopolymerization initiator, and oxadiazole photopolymerization initiator. An initiator or the like is used.
  • photopolymerization initiator examples include 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,2′-bis (o-chlorophenyl) -4,4 ′, 5,5′-tetraphenyl-1,2 '-Bisimidazole, 10-butyl-2-chloroacridone, 2-ethylanthraquinone, benzyl, 9,10-phenanthrenequinone, camphorquinone, methyl phenylglyoxylate, titanocene compounds and the like can also be used.
  • the amount of the photopolymerization initiator used is usually 0.5 to 20 parts by weight, preferably 1 to 5 parts by weight with respect to 100 parts by weight of the resin contained in the resin liquid.
  • the dispersion of the light-transmitting fine particles 106b in the resin solution is preferably isotropic dispersion.
  • Application of the resin liquid onto the transparent substrate film 105 can be performed, for example, by a gravure coating method, a micro gravure coating method, a rod coating method, a knife coating method, an air knife coating method, a kiss coating method, a die coating method, or the like.
  • the coating film thickness is adjusted so that the thickness of the light diffusion layer 106 is 1 to 3 times the weight average particle diameter of the translucent fine particles 106b. It is preferable to do.
  • Various surface treatments may be applied to the surface of the transparent base film 105 (the surface on the light diffusion layer 106 side) for the purpose of improving the coating property of the resin liquid or improving the adhesion with the light diffusion layer 106.
  • the surface treatment include corona discharge treatment, glow discharge treatment, acid surface treatment, alkali surface treatment, and ultraviolet irradiation treatment.
  • another layer such as a primer layer (easy adhesion layer) may be formed on the transparent base film 105, and the resin liquid may be applied on the other layer.
  • the surface of the transparent substrate film 105 opposite to the surface on the light diffusion layer 106 side is subjected to the surface treatment as described above. It is preferable.
  • the light diffusing film 102 includes a step of applying a resin liquid in which translucent fine particles 106b are dispersed on a transparent base film 105, and a mirror surface or an uneven surface of a mold on the surface of a layer formed from the resin liquid. It can also be formed by a method including a transfer step. That is, the light diffusing layer 106 having the center line average roughness Ra is a mold (mirror mold) having a mirror surface on the surface of the layer formed from the resin liquid, if necessary. It can be formed by closely contacting the uneven surface of a mold having a mirror surface or an uneven surface (embossing mold) and transferring the mirror surface or the uneven surface.
  • the mirror surface mold may be a mirror surface metal roll, and the embossing mold may be an embossing metal roll.
  • thermosetting resin thermoplastic resin or metal alkoxide
  • a layer made of the resin liquid is formed and dried (removal of the solvent) as necessary. If necessary, with the mirror surface or uneven surface of the mold in close contact with the surface of the layer made of the resin liquid, irradiation with ionizing radiation (when using ionizing radiation curable resin), The layer made of the resin liquid is cured by heating (when using a thermosetting resin or metal alkoxide) or cooling (when using a thermoplastic resin).
  • the ionizing radiation can be appropriately selected from ultraviolet rays, electron beams, near ultraviolet rays, visible rays, near infrared rays, infrared rays, X-rays, etc. depending on the type of resin contained in the resin liquid.
  • ultraviolet rays An electron beam is preferable, and ultraviolet rays are particularly preferable because of easy handling and high energy.
  • a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, or the like can be used.
  • An ArF excimer laser, a KrF excimer laser, an excimer lamp, synchrotron radiation, or the like can also be used.
  • an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a xenon lamp, and a metal halide lamp are preferably used.
  • the electron beam 50 to 1000 keV emitted from various electron beam accelerators such as Cockloft Walton type, Bande graph type, resonance transformation type, insulation core transformation type, linear type, dynamitron type, and high frequency type, preferably 100 Mention may be made of electron beams having an energy of ⁇ 300 keV.
  • various electron beam accelerators such as Cockloft Walton type, Bande graph type, resonance transformation type, insulation core transformation type, linear type, dynamitron type, and high frequency type, preferably 100 Mention may be made of electron beams having an energy of ⁇ 300 keV.
  • the step of continuously feeding the transparent base film 105 wound in a roll shape the translucent fine particles 106b are dispersed. It includes a step of applying a resin liquid and drying it as necessary, a step of curing a layer formed from the resin liquid, and a step of winding up the obtained light diffusion film 102.
  • a manufacturing method can be implemented, for example, using a manufacturing apparatus shown in FIG.
  • the transparent base film 105 is continuously unwound by the unwinding device 301.
  • a resin liquid in which the translucent fine particles 106 b are dispersed is applied onto the unwound transparent base film 105 using the coating device 302 and the backup roll 303 facing the coating device 302.
  • the transparent substrate film 105 coated with the resin liquid is dried by passing it through the dryer 304.
  • the transparent base film 105 provided with the layer formed from the resin liquid is formed between the mirror-made metal roll or the embossing metal roll 305 and the nip roll 306, and the layer formed from the resin liquid is It is unwound so as to be in close contact with the mirror surface metal roll or the embossing metal roll 305. Thereby, the mirror surface of the mirror surface metal roll or the uneven surface of the metal roll for embossing is transferred to the surface of the layer formed from the resin liquid.
  • ultraviolet rays are irradiated from the ultraviolet irradiation device 308 through the transparent substrate film 105 in a state where the layer formed from the resin liquid on the transparent substrate film 105 is in close contact with the mirror surface metal roll or the embossing metal roll 305.
  • the layer formed from the resin liquid is cured to form the light diffusion layer 106.
  • the mirror surface metal roll or the embossing metal roll 305 preferably includes a cooling device for adjusting the surface temperature to about room temperature to 80 ° C. .
  • one or a plurality of ultraviolet irradiation devices 308 can be used.
  • the transparent substrate film 105 (light diffusion film 102) on which the light diffusion layer 106 is formed is peeled off from the mirror surface metal roll or the embossing metal roll 305 by the peeling roll 307.
  • the light diffusion film 102 manufactured as described above is wound up by the winding device 309. At this time, for the purpose of protecting the light diffusion layer 106, light is applied to the surface of the light diffusion layer 106 while attaching a surface protective film formed of polyethylene terephthalate, polyethylene or the like through a pressure-sensitive adhesive layer having removability.
  • the diffusion film 102 may be wound up.
  • additional ultraviolet irradiation may be performed after peeling from the mirror surface metal roll or the embossing metal roll 305 by the peeling roll 307.
  • additional ultraviolet irradiation instead of performing ultraviolet irradiation in a state where the mirror metal roll or the embossing metal roll 305 and the layer formed from the resin liquid are in close contact with each other, a transparent layer formed from an uncured resin liquid is formed.
  • the layer formed from the resin liquid may be cured by irradiating ultraviolet rays.
  • the light diffusion film 102 and the polarizing film 101 are bonded to each other through an adhesive layer or the like.
  • the light diffusing film 102 also functions as a protective film for the polarizing film 101, and such a configuration is advantageous for reducing the thickness of the light diffusing polarizing plate 100.
  • the bonding using the adhesive between the light diffusion film 102 and the polarizing film 101 is performed by the same method using the same adhesive as described later for the bonding between the surface treatment film 103 and the light diffusion film 102. Can do.
  • the surface treatment film 103 is a film in which one surface of the transparent resin film 107 is optically treated. Specifically, the surface treatment layer 108 having a desired optical function on one surface of the transparent resin film 107. It can be a film formed.
  • the transparent resin film 107 for example, a cellulose acetate resin such as TAC (triacetyl cellulose); an acrylic resin such as polymethyl methacrylate; a polycarbonate resin; and a polyester resin such as polyethylene terephthalate; A film can be used.
  • the thickness of the transparent resin film 107 is, for example, 10 to 500 ⁇ m, and preferably 20 to 300 ⁇ m.
  • the surface treatment layer 108 is an anti-glare layer having irregularities on the surface, and reduces or prevents reflection of external light on the display screen by using irregular reflection due to the irregularities on the surface.
  • the antiglare film that is, the optical treatment is an antiglare treatment
  • the surface treatment layer 108 is an antireflection layer, which reduces or prevents the reflection of external light incident on the display screen to the display screen.
  • An antireflection film that reduces or prevents reflection of external light that is, the optical treatment is an antireflection treatment
  • the antiglare film for example, a mold having a predetermined surface irregularity on the ultraviolet curable resin layer formed by coating an ultraviolet curable resin composition containing or not containing fine particles on the transparent resin film 107. And an ultraviolet curable resin containing fine particles on the transparent resin film 107 formed by curing the ultraviolet curable resin layer while pressing the concavo-convex surface of the transparent resin film 107. Applying the composition and using an anti-glare layer provided with predetermined surface irregularities by fine particles formed by curing the applied UV-curable resin layer without using a mold Can do.
  • a commercially available anti-glare film can also be used as the anti-glare film.
  • an antireflection film for example, a film having a low refractive index layer made of a material having a refractive index lower than that of the light diffusion layer 106 as an antireflection layer, or a refractive index higher than the refractive index of the light diffusion layer 106 is used.
  • the low refractive index layer is, for example, silica; metal fluoride fine particles (LiF, MgF, 3NaF / AlF, AlF, Na 3 AlF 6 etc.); fine particles having voids inside (hollow silica fine particles etc.); fluorine-containing polymer; And a low refractive index material and a binder resin.
  • the binder resin may be a conventionally known one, and is a polysiloxane resin, a hydrolyzate of silicon alkoxide, a light or thermosetting multi-branched compound (such as a dendrimer or a hyperbranched polymer), or other light or thermosetting resin. be able to.
  • One or more of other layers such as a hard coat layer and an antistatic layer may be interposed between the transparent resin film 107 and the low refractive index layer or the high refractive index layer.
  • a commercially available antireflection film can also be used as the antireflection film.
  • the surface treatment film 103 is usually a surface opposite to the surface of the transparent resin film 107 close to the surface treatment layer 108 (optical treatment of the surface treatment film 103 is performed).
  • the surface treatment film 103 is usually a surface opposite to the surface of the transparent resin film 107 close to the surface treatment layer 108 (optical treatment of the surface treatment film 103 is performed).
  • the surface treatment film 103 is usually a surface opposite to the surface of the transparent resin film 107 close to the surface treatment layer 108 (optical treatment of the surface treatment film 103 is performed).
  • the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer 104 conventionally known ones can be used, and examples thereof include acrylic pressure-sensitive adhesives, urethane pressure-sensitive adhesives, and silicone-based pressure-sensitive adhesives. Among these, an acrylic pressure-sensitive adhesive is preferably used from the viewpoints of transparency, adhesive strength, reliability, reworkability, and the like.
  • the pressure-sensitive adhesive layer 104 can be provided by a method in which such a pressure-sensitive adhesive is, for example, an organic solvent solution, which is applied onto the light diffusion layer 106 or the transparent resin film 107 by a die coater or a gravure coater and dried.
  • a sheet-like pressure-sensitive adhesive formed on a plastic film (referred to as a separate film) subjected to a release treatment to the light diffusion layer 106 or the transparent resin film 107.
  • the thickness of the pressure-sensitive adhesive layer is usually in the range of 2 to 40 ⁇ m.
  • an epoxy resin can be used because the surface treatment film 103 and the light diffusion film 102 can be bonded with high adhesive strength without adversely affecting the appearance of the light diffusing polarizing plate 100.
  • An adhesive containing an active energy ray or a thermosetting resin composition such as a curable resin composition containing water, or an aqueous adhesive containing a polyvinyl alcohol resin or a urethane resin as an adhesive component can be preferably used. .
  • the adhesive agent containing the curable resin composition containing an epoxy resin is used more preferable.
  • Bonding of the surface treatment film 103 and the light diffusion film 102 using an adhesive containing a curable resin composition containing an epoxy resin is performed by applying the adhesive on the light diffusion layer 106 or the transparent resin film 107. Then, after laminating both films via an uncured adhesive layer, the film can be cured by irradiating with active energy rays or heating to cure the uncured adhesive layer.
  • various coating methods such as a doctor blade, a wire bar, a die coater, a comma coater, and a gravure coater can be used. Since each coating method has an optimum viscosity range, the viscosity of the adhesive may be adjusted using an organic solvent.
  • the thickness of the adhesive layer after curing is usually 0.1 to 20 ⁇ m, preferably 0.2 to 10 ⁇ m, more preferably 0.5 to 5 ⁇ m.
  • the bonding surface of the transparent resin film 107 and / or the light diffusion layer 106 is subjected to an easy adhesion process such as a corona discharge process or a primer process (formation of a primer layer). May be.
  • the light diffusing polarizing plate of the present invention may include a protective film 109 laminated on the opposite side of the polarizing film 101 from the light diffusing film 102 via an adhesive layer or the like.
  • the protective film 109 is preferably a film made of a polymer that has low birefringence and is excellent in transparency, mechanical strength, thermal stability, moisture shielding properties, and the like.
  • Such films include cellulose acetate resins such as TAC (triacetyl cellulose); acrylic resins; fluorine resins such as tetrafluoroethylene / hexafluoropropylene copolymers; polycarbonate resins; polyethylenes Polyester resin such as terephthalate; Polyimide resin; Polysulfone resin; Polyethersulfone resin; Polystyrene sulfone resin; Polyvinyl alcohol resin; Polyvinyl chloride resin; Resin film composed of polyolefin resin or polyamide resin Is mentioned.
  • a triacetyl cellulose film and a norbornene-based thermoplastic resin film can be preferably used from the viewpoints of polarization characteristics and durability.
  • the norbornene-based thermoplastic resin film is particularly suitable because it has high moisture and heat resistance and can greatly improve the durability of the polarizing plate and has high dimensional stability because of low hygroscopicity.
  • a conventionally known method such as a casting method, a calendar method, and an extrusion method can be used.
  • the thickness of the protective film 109 is not limited. To 500 ⁇ m or less, more preferably in the range of 5 to 300 ⁇ m, still more preferably in the range of 5 to 150 ⁇ m.
  • the bonding using the adhesive between the polarizing film 101 and the protective film 109 can be performed by the same method using the same adhesive as described above for the bonding between the surface treatment film 103 and the light diffusion film 102. it can.
  • an optical compensation film such as a retardation film (retardation plate) may be bonded to the polarizing film 101 instead of the protective film 109.
  • the light diffusing polarizing plate 100 having the above-described configuration is applied to a liquid crystal display device, an adhesive layer or the like is interposed so that the surface treatment film 103 is closer to the viewing side than the polarizing film 101. Then, it is attached to the glass substrate of the liquid crystal cell and incorporated into the liquid crystal display device.
  • the liquid crystal display device of the present invention comprises a backlight device, a light diffusion means, a backlight side polarizing plate, a liquid crystal cell, and the light diffusing polarizing plate of the present invention in this order.
  • FIG. 3 is a schematic sectional view showing a preferred example of the liquid crystal display device of the present invention.
  • the liquid crystal display device 400 of FIG. 3 is a normally white mode TN liquid crystal display device, which is a backlight device 402, a light diffusion means 403, a backlight side polarizing plate 404, and a viewing side polarizing plate.
  • the light diffusing polarizing plate 405 is arranged in this order, and the liquid crystal cell 401 includes a liquid crystal layer 412 and a pair of transparent substrates 411 a and 411 b arranged on both surfaces of the liquid crystal layer 412.
  • the backlight side polarizing plate 404 and the light diffusing polarizing plate 405 are disposed so that their transmission axes have a crossed Nicols relationship.
  • the backlight device 402 is a direct-type backlight device including a hexahedron-shaped case 421 having a front opening and a plurality of cold cathode tubes 422 as linear light sources arranged in parallel in the case 421.
  • the light diffusing unit 403 is provided on the front surface of the backlight device 402, and on the front side of the light diffusing plate 403a (between the light diffusing plate 403a and the backlight side polarizing plate 404). And an optical deflection plate (prism sheet) 403b.
  • the light emitted from the backlight device 402 is diffused by the light diffusing plate 403a of the light diffusing means 403, and then the light incident surface of the liquid crystal cell 401 by the light deflecting plate 403b.
  • Predetermined directivity in the perpendicular direction (z-axis direction) is given.
  • the directivity in the perpendicular direction is set to be higher than that of the conventional device.
  • the light having a predetermined directivity is polarized by the backlight side polarizing plate 404 and enters the liquid crystal cell 401.
  • the light incident on the liquid crystal cell 401 is emitted from the liquid crystal cell 401 with the polarization state controlled by the liquid crystal layer 412.
  • the light emitted from the liquid crystal cell 401 is diffused by the light diffusing polarizing plate 405.
  • the directivity of the light incident on the liquid crystal cell 401 in the light diffusing unit 403 in the perpendicular direction (z-axis direction) of the light incident surface of the liquid crystal cell 401 is higher than before. That is, the incident light to the liquid crystal cell 401 is collected more than before, and this is further diffused by the light diffusing polarizing plate 405. This makes it possible to obtain an excellent image quality such as color reproducibility as compared with the conventional apparatus.
  • the liquid crystal display device 400 of the present invention to which the light diffusing polarizing plate 405 of the present invention is applied has high viewing angle characteristics and also has an optical function other than the light diffusing function provided to the light diffusing polarizing plate 405. Excellent visibility.
  • the liquid crystal cell 401 includes a pair of transparent substrates 411a and 411b and a liquid crystal layer 412.
  • the pair of transparent substrates 411a and 411b are arranged to face each other with a predetermined distance by a spacer, and the liquid crystal layer 412 includes a pair of transparent substrates 411a and 411a. It is composed of liquid crystal sealed between 411b.
  • the pair of transparent substrates 411a and 411b are each formed by laminating a transparent electrode and an alignment film, and the liquid crystal is aligned by applying a voltage based on display data between the transparent electrodes.
  • the display method of the liquid crystal cell 401 is the TN method in the above example, but a display method such as an IPS method or a VA method may also be adopted.
  • the backlight device 402 includes a hexahedron-shaped case 421 having a front opening, and a plurality of cold cathode tubes 422 as linear light sources arranged in parallel in the case 421.
  • the case 421 is molded from a resin material or a metal material, and at least the inner peripheral surface of the case 421 is desirably white or silver from the viewpoint of reflecting the light emitted from the cold cathode fluorescent lamp 422 on the inner peripheral surface of the case 421.
  • LEDs of various shapes such as a linear shape can be used in addition to a cold cathode tube.
  • the number of the linear light sources to be arranged is not particularly limited, but the distance between the centers of the adjacent linear light sources is in the range of 15 mm to 150 mm from the viewpoint of suppressing luminance unevenness on the light emitting surface. It is preferable.
  • the backlight device 402 used in the present invention is not limited to the direct type shown in FIG. 3, but is a sidelight type in which a linear light source or a point light source is arranged on the side surface of the light guide plate, or a flat type. Various types such as a shape light source type can be used.
  • the light diffusing unit 403 includes a light diffusing plate 403a disposed on the front surface of the backlight device 402, and a front surface side of the light diffusing plate 403a (light diffusing plate 403a and backlight side polarizing plate 404). And a light deflection plate (prism sheet) 403b provided between the two.
  • the light diffusing plate 403 a can be a film or sheet in which a light diffusing agent 440 is dispersed and mixed with a base material 430.
  • polycarbonate resin As the base material 430, polycarbonate resin; methacrylic resin; methyl methacrylate-styrene copolymer resin; acrylonitrile-styrene copolymer resin; methacrylic acid-styrene copolymer resin; polystyrene resin; Polyolefin resins such as polypropylene and polymethylpentene; cyclic polyolefin resins; polyester resins such as polyethylene terephthalate, polybutylene terephthalate and polyethylene naphthalate; polyamide resins; polyarylate resins; polyimide resins; .
  • the light diffusing agent 440 mixed and dispersed in the base material 430 is not particularly limited as long as it is a fine particle formed of a material having a refractive index different from that of the base material 430.
  • it is different from the material of the base material 430.
  • Organic fine particles formed from various types of acrylic resin, melamine resin, polyethylene resin, polystyrene resin, organic silicone resin, acrylic-styrene copolymer resin, and calcium carbonate, silica, aluminum oxide, barium carbonate, barium sulfate, oxidation Inorganic fine particles formed from titanium, glass and the like can be mentioned. Only one type of light diffusing agent 440 may be used, or two or more types may be used in combination.
  • the weight average particle diameter of the light diffusing agent 440 is preferably in the range of 0.5 to 30 ⁇ m.
  • the light diffusing agent 440 may have a spherical shape, a flat shape, a plate shape, a needle shape, or the like, but is preferably a spherical shape.
  • the light deflection plate (prism sheet) 403b has a flat surface on the light incident surface side (the backlight device 402 side, the negative direction side of the z axis shown in FIG. 4) and the light emitting side (z shown in FIG. 4).
  • a plurality of linear prisms 450 having a tapered cross section, preferably a triangular shape, are formed in parallel on the surface on the positive side of the axis (the surface facing the backlight side polarizing plate 404).
  • Examples of the material of the light deflector 403b include polycarbonate resin; ABS resin; methacrylic resin; methyl methacrylate-styrene copolymer resin; polystyrene resin; acrylonitrile-styrene copolymer resin; polyolefins such as polyethylene and polypropylene. Resin; and the like.
  • a method for producing the light deflection plate 403b a normal thermoplastic resin molding method can be used, and examples thereof include hot press molding using a mold and extrusion molding.
  • the thickness of the light deflection plate 403b is usually 0.1 to 15 mm, preferably 0.5 to 10 mm.
  • the “thickness of the light deflection plate” refers to the maximum thickness from the surface of the light deflection plate 403b close to the light diffusion plate 403a to the apex of the apex angle of the linear prism 450. Point to. Therefore, the thickest portion corresponding to B shown in FIG. 4 is the thickness of the light deflection plate 403b. In a portion where the thickness from the surface of the light deflecting plate 403b close to the light diffusing plate 403a to the tip of the apex angle of the linear prism 450 is not maximum (for example, the valley portion of the linear prism 450), the light deflecting plate 403b. The thickness may not be in the above range.
  • the light diffusing plate 403a and the light deflecting plate 403b may be integrally formed, or may be formed separately and then joined. Further, in the case of separately producing and joining, the light diffusing plate 403a and the light deflecting plate 403b may be contacted via an air layer. Further, the light diffusion plate 403a and the light deflection plate 403b may be arranged apart from each other.
  • the light diffusing unit 403 may be provided with a light diffusing function by dispersing and mixing a light diffusing agent 440 on a light deflecting plate 403 b having a light deflecting function.
  • the light diffusing unit 403 may include two light deflecting plates (prism sheets) 403b and 403b 'disposed on the front side of the light diffusing plate 403a.
  • the direction of the ridge line 451 of the linear prism 450 is the transmission axis direction (y
  • the light deflection plate 403b ′ disposed substantially parallel to the axial direction) and disposed on the front surface side of the light deflection plate 403b has a direction of the ridge line 451 ′ of the linear prism 450 ′ as a light diffusing polarizing plate.
  • the light deflection plate 403b ′ is arranged so that the direction of the ridge line 451 ′ of the linear prism 450 ′ of the light deflection plate 403b ′ is substantially parallel to the transmission axis direction (y-axis direction) of the backlight side polarizing plate 404, and the light deflection plate 403b.
  • the ridge line 451 of the linear prism 450 may be arranged so as to be substantially parallel to the transmission axis direction (x-axis direction) of the light diffusing polarizing plate 405.
  • the light distribution characteristic of the light that has passed through the light diffusing means 403 is such that the luminance value in the direction inclined by 70 ° from the perpendicular direction (z-axis direction shown in FIG. 3) of the light incident surface of the liquid crystal cell 401 is the front luminance value. It is preferable that it is 20% or less with respect to the luminance value in the perpendicular direction of the light incident surface of the liquid crystal cell 401, and the light emitted from the light diffusing means 403 includes non-parallel light.
  • a more preferable light distribution characteristic is that no light is emitted in a direction exceeding 60 ° with respect to the normal of the light incident surface of the liquid crystal cell 401. Normally, as shown in FIG.
  • the back surface (light incident surface) of the light diffusing means 403 and the light incident surface of the liquid crystal cell 401 are arranged in parallel, so that the perpendicular to the light incident surface of the liquid crystal cell 401 is
  • the luminance value in the 70 ° direction is, for example, as shown in FIG. 7, where the longitudinal direction of the light diffusing unit 403 is the x direction and the plane parallel to the back surface (light incident surface) of the light diffusing unit 403 is the xy plane.
  • the luminance value is in the direction of 70 ° with respect to the z axis, which is a perpendicular to the xy plane, and preferably the luminance value in the direction in which the angle formed with the z axis on the xz plane is 70 °.
  • the shape of the linear prism 450 (and / or the linear prism 450 ') having a triangular cross section of the light deflection plate 403b may be adjusted.
  • the apex angle ⁇ (see FIGS. 4 and 5) of the linear prisms 450 and 450 ′ is preferably in the range of 60 to 120 °, more preferably 90 to 110 °.
  • an equal side and an unequal side can be arbitrarily selected, but an isosceles triangle is preferable in the case where light is focused in the perpendicular direction of the liquid crystal cell 401 (the front direction of the liquid crystal display device, that is, the z-axis direction).
  • the prism surface composed of linear prisms is arranged sequentially so that the bases corresponding to the apex angles of the triangles are adjacent to each other, and a plurality of linear prisms are arranged so as to be substantially parallel to each other. Is preferred.
  • the V-shaped grooves formed by the apexes of the linear prisms and the adjacent linear prisms may be curved as long as the light collecting ability is not significantly reduced.
  • the distance between the ridgelines of the linear prism (distance d shown in FIGS. 4 and 5) is usually in the range of 10 ⁇ m to 500 ⁇ m, and preferably in the range of 30 ⁇ m to 200 ⁇ m.
  • non-parallel light means that light emitted from a circle having a diameter of 1 cm on the exit surface of the light diffusing means 403 is parallel to the exit surface, which is 1 m away from the exit surface in the perpendicular direction.
  • the light has emission characteristics such that the minimum half-value width of the in-plane luminance distribution of the projection image is 30 cm or more.
  • Backlight side polarizing plate As the backlight-side polarizing plate 404, a polarizing film in which a protective film is bonded to one side or both sides can be usually used. As a polarizing film and a protective film, what was mentioned above about the light diffusable polarizing plate 100 can be used.
  • the liquid crystal display device of the present invention can include a retardation plate 406.
  • the retardation film 406 is disposed between the backlight side polarizing plate 404 and the liquid crystal cell 401.
  • This phase difference plate 406 has a phase difference of almost zero in the direction perpendicular to the surface of the liquid crystal cell 401 (z-axis direction), has no optical effect from the front, and is viewed from an oblique direction. A phase difference is sometimes developed, and the phase difference generated in the liquid crystal cell 401 is compensated. This makes it possible to obtain better display quality and color reproducibility over a wider viewing angle.
  • the retardation plate 406 can be disposed between the backlight side polarizing plate 404 and the liquid crystal cell 401 and between one or both of the light diffusing polarizing plate 405 and the liquid crystal cell 401.
  • the retardation film 406 can be laminated on the protective film of the backlight side polarizing plate 404, or can also be laminated directly on the polarizing film of the backlight side polarizing plate 404 while also serving as a protective film. .
  • phase difference plate 406 for example, a polycarbonate resin or a cyclic olefin polymer resin is used as a film, and this film is further biaxially stretched, or a liquid crystalline monomer is applied to the film, and its molecular arrangement is changed by a photopolymerization reaction. Immobilized ones are listed.
  • the phase difference plate 406 optically compensates for the alignment of the liquid crystal, and therefore has a refractive index characteristic opposite to that of the liquid crystal alignment.
  • a TN mode liquid crystal cell for example, “WV film” (manufactured by FUJIFILM Corporation)
  • STN mode liquid crystal display cell for example, “LC film” (manufactured by Nippon Oil Corporation)
  • LC film manufactured by Nippon Oil Corporation
  • IPS mode liquid crystal display cells for example, a biaxial retardation film
  • VA mode liquid crystal display cells for example, a retardation plate or a biaxial retardation film combining a A plate and a C plate
  • a ⁇ cell for the mode liquid crystal display cell, for example, “OCB WV film” (manufactured by FUJIFILM Corporation) can be suitably used.
  • the methods for measuring the haze and surface centerline average roughness Ra of the light diffusion film, the thickness of the light diffusion layer, and the weight average particle diameter of the light-transmitting fine particles used are as follows.
  • (C) Light diffusing layer thickness The thickness of the light diffusing film is measured using DIGIMICRO MH-15 (main body) and ZC-101 (counter) manufactured by NIKON, and the substrate thickness of 80 ⁇ m is subtracted from the measured layer thickness. Was used to measure the thickness of the light diffusion layer.
  • the surface of a 200 mm diameter iron roll (STKM13A by JIS) was prepared by applying copper ballad plating.
  • the copper ballad plating was formed from a copper plating layer / a thin silver plating layer / a surface copper plating layer, and the thickness of the entire plating layer was about 200 ⁇ m.
  • the copper-plated surface is mirror-polished, and zirconia beads TZ-B125 (manufactured by Tosoh Corporation, average particle size: 125 ⁇ m) are further polished on the polished surface using a blasting device (manufactured by Fuji Seisakusho).
  • Blasting was performed at a blast pressure of 0.05 MPa (gauge pressure, the same shall apply hereinafter) and a fine particle usage amount of 16 g / cm 2 (a usage amount per 1 cm 2 of surface area of the roll, the same applies hereinafter) to form irregularities on the surface.
  • a blasting device manufactured by Fuji Seisakusho
  • zirconia beads TZ-SX-17 manufactured by Tosoh Corporation, average particle size: 20 ⁇ m
  • blast pressure 0.1 MPa using fine particles Blasting was performed at an amount of 4 g / cm 2 to finely adjust the surface irregularities.
  • the resulting copper-plated iron roll with unevenness was etched with a cupric chloride solution (etching amount: 3 ⁇ m). Then, chromium plating processing (thickness of chromium plating: 4 ⁇ m) was performed to produce a metal embossing roll.
  • the Vickers hardness of the chrome-plated surface of the obtained metal embossing roll was 1000. The Vickers hardness was measured according to JIS Z 2244 using an ultrasonic hardness tester MIC10 (manufactured by Krautkramer).
  • This coating solution was applied on a transparent resin film which is a 80 ⁇ m thick triacetyl cellulose (TAC) film, and dried for 1 minute in a drier set at 80 ° C.
  • TAC triacetyl cellulose
  • the dried transparent resin film was pressed and adhered to the uneven surface of the metal embossing roll with a rubber roll so that the ultraviolet curable resin composition layer was on the roll side.
  • light from a high-pressure mercury lamp having an intensity of 20 mW / cm 2 is irradiated from the transparent resin film side so that the amount of light in terms of h-line is 300 mJ / cm 2 to cure the ultraviolet curable resin composition layer, and transparent An antiglare film having an antiglare layer formed on the resin film was obtained.
  • This coating solution was applied onto a transparent resin film (refractive index: 1.49), which is a TAC film having a thickness of 80 ⁇ m, with a wire bar coater and dried in a dryer set at 80 ° C. for 1 minute.
  • a hard coat layer was formed on the transparent resin film after drying by irradiating with ultraviolet rays at a power of 120 W from a distance of 20 cm for 10 seconds using a metal halide lamp.
  • the obtained hard coat layer had a thickness of 5 ⁇ m and a refractive index of 1.52.
  • ATO antimony-doped tin oxide
  • the TAC film on which the hard coat layer is formed is immersed in a 1.5N-NaOH aqueous solution at 50 ° C. for 2 minutes for alkali treatment, washed with water, and then washed with 0.5 wt% H 2 SO 4 aqueous solution at room temperature. It was neutralized by dipping for 30 seconds, further washed with water, and dried.
  • the antistatic layer-forming coating solution was applied onto the alkali-treated hard coat layer with a wire bar coater and dried in a drier set at 120 ° C. for 1 minute to form an antistatic layer.
  • the resulting antistatic layer had a thickness of 163 nm, a refractive index of 1.53, and an optical film thickness of 250 nm.
  • the obtained coating solution for forming a low refractive index layer was coated on the antistatic layer with a wire bar coater and dried in a dryer set at 120 ° C. for 1 minute to form a low refractive index layer.
  • the obtained low refractive index layer had a thickness of 91 nm, a refractive index of 1.37, and an optical film thickness of 125 nm.
  • an antireflection film including a hard coat layer, an antistatic layer, and a low refractive index layer on a transparent resin film was produced.
  • 10 polystyrene particles having a weight average particle diameter of 3.0 ⁇ m and a standard deviation of 0.39 ⁇ m are used as the first light-transmitting fine particles with respect to 100 parts by weight of the solid content of the ultraviolet curable resin composition.
  • This coating solution was applied onto a TAC film (transparent substrate film) having a thickness of 80 ⁇ m, dried for 1 minute in a drier set at 80 ° C., and then strength 20 mW / cm 2 from the transparent substrate film side.
  • Light from a high-pressure mercury lamp is irradiated so as to be 300 mJ / cm 2 in terms of the amount of h-ray conversion, the ultraviolet curable resin composition layer is cured, and light diffusion comprising a light diffusion layer and a transparent substrate film Film A was obtained.
  • the total haze, internal haze, and surface haze of the obtained light diffusion film A were 65.8%, 48.2%, and 17.6%, respectively. Further, the center line average roughness Ra of the surface was 0.42 ⁇ m, and the thickness of the light diffusion layer was 10.9 ⁇ m.
  • Example 1 After the corona treatment is applied to the surface of the transparent base film of the light diffusion film A obtained in Production Example 3, an ultraviolet curable adhesive containing an ultraviolet curable epoxy resin and a cationic photopolymerization initiator is thickened on the corona treatment surface. Coating was performed at 4 ⁇ m. On the other hand, after a corona treatment was applied to one side of a TAC film (thickness 80 ⁇ m) as a protective film, the same UV curable adhesive as described above was applied to the corona treatment surface with a thickness of 4 ⁇ m.
  • the light diffusing film A is laminated on one surface of a polarizing film formed by adsorbing and orienting iodine on a uniaxially stretched polyvinyl alcohol-based resin film, and the protection is provided on the other surface.
  • the film was laminated through the adhesive layer and sandwiched between a pair of nip rolls. Then, the ultraviolet-ray was irradiated from the protective film side, both the adhesive bond layers were hardened, and the light diffusable polarizing plate was obtained.
  • Example 2 a light diffusing polarizing plate subjected to an antireflection treatment was obtained in the same manner as in Example 1 except that the antireflection film obtained in Production Example 2 was used.
  • Example 1 instead of the laminate (used in Example 1) in which the light diffusion film A and the antiglare film are laminated via an adhesive layer, the surface of the light diffusion layer of the light diffusion film A is replaced with the metal embossing roll.
  • a light diffusing polarizing plate subjected to an antiglare treatment was obtained in the same manner as in Example 1 except that a film having an antiglare treatment applied to the light diffusion layer was used by pressing the concavo-convex surface with a rubber roll. .
  • Example 2 instead of the above laminate (used in Example 2) in which the light diffusion film A and the antireflection film are laminated via an adhesive layer, the surface of the light diffusion layer of the light diffusion film A has
  • the anti-reflection treatment was performed in the same manner as in Example 2 except that the anti-reflection layer and the low-refractive index layer were sequentially formed, and the light diffusion layer was subjected to an anti-reflection treatment.
  • the obtained light diffusable polarizing plate was obtained.
  • Color unevenness is a phenomenon in which the inside of the surface looks rainbow-colored in the above visual observation due to in-plane non-uniformity on the antireflection treatment surface. When such color unevenness occurs, the antireflection function is poor. It is judged that there is.
  • DESCRIPTION OF SYMBOLS 100,405 ... Light diffusable polarizing plate, 101 ... Polarizing film, 102 ... Light diffusing film, 103 ... Surface treatment film, 104 ... Adhesive layer or adhesive layer, 105 ... Transparent base film, 106 ... Light diffusing layer, 106a ... translucent resin, 106b ... translucent fine particles, 107 ... transparent resin film, 108 ... surface treatment layer, 109 ... protective film, 301 ... unwinding device, 302 ... coating device, 303 ... backup roll, 304 ... Dryer, 305 ... mirror surface metal roll or embossing metal roll, 306 ... nip roll, 307 ... peeling roll, 308 ...
  • ultraviolet irradiation device 309 ... winding device, 400, 400 '... liquid crystal display device, 401 ... liquid crystal Cell, 402 ... Backlight device, 403 ... Light diffusing means, 403a ... Light diffusing plate, 403b, 403b '... Light Direction plate, 404 ... Backlight side polarizing plate, 406 ... Phase difference plate, 411a, 411b ... Transparent substrate, 412 ... Liquid crystal layer, 421 ... Case, 422 ... Cold cathode tube, 430 ... Base material, 440 ... Light diffusing agent, 450, 450 '... linear prism, 451, 451' ... ridge line of linear prism.

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  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Chemical & Material Sciences (AREA)
  • Dispersion Chemistry (AREA)
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Abstract

Disclosed is a new light-diffusing polarization plate that diffuses light sufficiently and also provides other good optical functionality. Also disclosed is a liquid-crystal display device (400) using said light-diffusing polarization plate. The light-diffusing polarization plate (100) is provided with: a polarizing film (101); a light-diffusing film (102) laminated onto the polarizing film (101); and a surface-treated film (103) laminated onto the light-diffusing film (102). The light-diffusing film (102) has a light-diffusing layer (106), and the centerline average roughness (Ra) of the surface of the light-diffusing layer (106) closer to the surface-treated film (103) is at least 0.1 µm and less than 1 µm. The surface-treated film (103) is formed from a transparent resin film (107), one surface of which is optically treated. The light-diffusion layer (106) and the surface-treated film (103) are bonded to each other by an adhesive or pressure-sensitive adhesive layer (104).

Description

光拡散性偏光板および液晶表示装置Light diffusing polarizing plate and liquid crystal display device
　本発明は、光拡散性偏光板およびこれを用いた液晶表示装置に関する。 The present invention relates to a light diffusing polarizing plate and a liquid crystal display device using the same.
　近年、液晶表示装置は、携帯電話、パソコン用モニター、テレビ、液晶プロジェクタなどへの用途展開が急速に進んでいる。一般に、液晶表示装置は、バックライト装置と、液晶パネルとを備え、該液晶パネルは、液晶セル、該液晶セルのバックライト側に配置された背面側偏光板および該液晶セルの視認側に配置された前面側偏光板を含む。 In recent years, the use of liquid crystal display devices in mobile phones, monitors for personal computers, televisions, liquid crystal projectors, etc. is rapidly progressing. In general, a liquid crystal display device includes a backlight device and a liquid crystal panel, and the liquid crystal panel is disposed on a liquid crystal cell, a back side polarizing plate disposed on a backlight side of the liquid crystal cell, and a viewing side of the liquid crystal cell. The front side polarizing plate is included.
　従来、液晶表示装置においては、表示画面を斜め方向から見た場合に、高いコントラストが得られない、さらには画像の明暗が逆転する階調反転現象等により良好な表示特性が得られないなどといった問題、すなわち、視野角が狭いという問題が指摘されてきた。 Conventionally, in a liquid crystal display device, when the display screen is viewed from an oblique direction, high contrast cannot be obtained, and further, good display characteristics cannot be obtained due to a gradation reversal phenomenon in which the contrast of the image is reversed. The problem, that is, the problem that the viewing angle is narrow has been pointed out.
　このような視野角特性の問題を解決するための方法として、前面側偏光板に光拡散機能を付与する技術が従来知られている。たとえば、特開２００９－３０１０１４号公報（特許文献１）には、液晶セルの前面側（視認側）に、比較的高い光拡散性を有する偏光板（特許文献１では「第２光拡散層」と表現されている）を配置することが開示されている。この第２光拡散層は、たとえば、偏光板と、該偏光板の前面側に設けられる、比較的多量のフィラー（光拡散剤）を含有する光拡散機能が付与された樹脂層（光拡散層）とからなるものである。 As a method for solving such a problem of viewing angle characteristics, a technique for imparting a light diffusion function to the front-side polarizing plate is conventionally known. For example, JP 2009-301014 A (Patent Document 1) discloses a polarizing plate having a relatively high light diffusibility (“second light diffusion layer” in Patent Document 1) on the front side (viewing side) of a liquid crystal cell. Is disclosed). This second light diffusing layer is, for example, a polarizing plate and a resin layer (light diffusing layer) provided on the front side of the polarizing plate and provided with a light diffusing function containing a relatively large amount of filler (light diffusing agent). ).
特開２００９－３０１０１４号公報JP 2009-301014 A
　一方、液晶表示装置の視認性のさらなる改善を目的として、液晶表示装置の前面側の最表面、すなわち、前面側偏光板の最表面に、表示面に外光が映り込むことを防止または低減するための防眩処理や、表示面に入射した外光の反射を防止または低減するための反射防止処理などの光学的処理を施すことがある。これらの光学的処理が所定の機能を十分に発現するためには、光学的処理が施される表面の形状が精密に制御されている必要がある。 On the other hand, for the purpose of further improving the visibility of the liquid crystal display device, it is possible to prevent or reduce external light from being reflected on the display surface on the outermost surface of the liquid crystal display device, that is, the outermost surface of the front-side polarizing plate. In some cases, an optical process such as an anti-glare process or an anti-reflection process for preventing or reducing reflection of external light incident on the display surface is performed. In order for these optical treatments to fully exhibit a predetermined function, the shape of the surface on which the optical treatment is performed needs to be precisely controlled.
　しかしながら、上記特許文献１に記載の前面側偏光板が有する光拡散層のように、比較的多量のフィラーを含有する光拡散層は、極端に大きな突起が形成され、このような場合、該光拡散層の表面に上記のような光学的処理を直接施すことが困難であったり、あるいは、光学的処理を直接施すこと自体は可能であっても、防眩機能や反射防止機能等の所定の機能を良好に発現させることができなかったりすることがあった。 However, the light diffusion layer containing a relatively large amount of filler, such as the light diffusion layer of the front side polarizing plate described in Patent Document 1, has extremely large protrusions. Although it is difficult to directly apply the optical treatment as described above to the surface of the diffusion layer, or it is possible to directly apply the optical treatment itself, a predetermined antiglare function, antireflection function, etc. In some cases, the function could not be expressed well.
　そこで本発明の目的は、十分な光拡散性を有する偏光板であって、さらに別の光学機能をも良好に示す新たな光拡散性偏光板およびこれを用いた液晶表示装置を提供することにある。 Accordingly, an object of the present invention is to provide a new light diffusing polarizing plate which has a sufficient light diffusing property and which also exhibits another optical function and a liquid crystal display device using the same. is there.
　本発明は、偏光フィルムと、該偏光フィルム上に積層される光拡散フィルムと、該光拡散フィルム上に積層される表面処理フィルムとを備え、光拡散フィルムは、光拡散層を有し、光拡散層の表面のうち、表面処理フィルムに近い方の表面の中心線平均粗さＲａが０．１μｍ以上１μｍ未満であり、表面処理フィルムは、一方の表面に光学的処理が施された透明樹脂フィルムから形成され、光拡散層と、表面処理フィルムとが、粘着剤層または接着剤層を介して互いに貼合されている光拡散性偏光板を提供する。 The present invention includes a polarizing film, a light diffusing film laminated on the polarizing film, and a surface treatment film laminated on the light diffusing film, the light diffusing film having a light diffusing layer, Among the surfaces of the diffusion layer, the center line average roughness Ra of the surface closer to the surface treatment film is 0.1 μm or more and less than 1 μm, and the surface treatment film is a transparent resin in which one surface is optically treated Provided is a light diffusing polarizing plate which is formed from a film and in which a light diffusion layer and a surface treatment film are bonded to each other via an adhesive layer or an adhesive layer.
　本発明の光拡散性偏光板において、表面処理フィルムは、光学的処理が施されていない面を有し、光拡散層と、表面処理フィルムの光学的処理が施されていない面とが、粘着剤層または接着剤層を介して互いに貼合されて、光拡散層と表面処理フィルムとが貼合されていることが好ましい。 In the light diffusing polarizing plate of the present invention, the surface treatment film has a surface not subjected to optical treatment, and the light diffusion layer and the surface not subjected to optical treatment of the surface treatment film are adhesive. It is preferable that the light diffusion layer and the surface treatment film are bonded to each other through an agent layer or an adhesive layer.
　光学的処理は、たとえば、防眩処理または反射防止処理であることができる。 The optical treatment can be, for example, an antiglare treatment or an antireflection treatment.
　光拡散フィルムは、透明基材フィルムをさらに備え、該透明基材フィルム上に前記光拡散層が積層され、光拡散層は、透光性樹脂と、透光性樹脂中に分散されている透光性微粒子とを含むものであることが好ましい。このような光拡散フィルムの光拡散層は、透明基材フィルム上に、透光性微粒子が分散された樹脂液を塗布することにより形成することができる。また、光拡散層は、透光性微粒子が分散された樹脂液を透明基材フィルム上に塗布し、該樹脂液から形成される層の表面に金型の鏡面または凹凸面を転写することにより形成してもよい。 The light diffusing film further includes a transparent base film, and the light diffusing layer is laminated on the transparent base film, and the light diffusing layer is dispersed in the translucent resin and the translucent resin. It is preferable that it contains a light-sensitive fine particle. The light diffusion layer of such a light diffusion film can be formed by applying a resin liquid in which translucent fine particles are dispersed on a transparent substrate film. The light diffusion layer is formed by applying a resin liquid in which translucent fine particles are dispersed on a transparent substrate film, and transferring a mirror surface or an uneven surface of a mold onto the surface of the layer formed from the resin liquid. It may be formed.
　また本発明は、バックライト装置と、光拡散手段と、バックライト側偏光板と、液晶セルと、上記光拡散性偏光板とをこの順で備える液晶表示装置を提供する。本発明の液晶表示装置において、光拡散性偏光板は、偏光フィルムが表面処理フィルムよりも液晶セルに近くなるように、配置される。 The present invention also provides a liquid crystal display device comprising a backlight device, a light diffusing means, a backlight side polarizing plate, a liquid crystal cell, and the light diffusing polarizing plate in this order. In the liquid crystal display device of the present invention, the light diffusing polarizing plate is disposed so that the polarizing film is closer to the liquid crystal cell than the surface treatment film.
　本発明の液晶表示装置において、光拡散手段からの出射光は、液晶セルの光入射面の垂線方向から７０°傾いた方向の輝度が該垂線方向の輝度に対して２０％以下である配光特性を有し、かつ、非平行光を含むものであることが好ましい。 In the liquid crystal display device of the present invention, the light emitted from the light diffusing means has a light distribution in which the luminance in a direction inclined by 70 ° from the normal direction of the light incident surface of the liquid crystal cell is 20% or less with respect to the luminance in the normal direction. It is preferable that it has characteristics and includes non-parallel light.
　光拡散手段は、バックライト装置側から、光拡散板と、光偏向板とをこの順で備えるものであることができる。液晶セルとしては、ＴＮ（Ｔｗｉｓｔｅｄ　Ｎｅｍａｔｉｃ）方式液晶セル、ＩＰＳ（Ｉｎ－Ｐｌａｎｅ　Ｓｗｉｔｃｈｉｎｇ）方式液晶セルまたはＶＡ（Ｖｅｒｔｉｃａｌ　Ａｌｉｇｎｍｅｎｔ）方式液晶セルなどを用いることができる。 The light diffusing means can include a light diffusing plate and a light deflecting plate in this order from the backlight device side. As the liquid crystal cell, a TN (Twisted Nematic) type liquid crystal cell, an IPS (In-Plane Switching) type liquid crystal cell, a VA (Vertical Alignment) type liquid crystal cell, or the like can be used.
　本発明によれば、十分な光拡散性を有するとともに、さらに別の光学機能をも良好に示す光拡散性偏光板を提供できる。 According to the present invention, it is possible to provide a light diffusable polarizing plate that has sufficient light diffusibility and also exhibits other optical functions well.
本発明の光拡散性偏光板の好ましい一例を示す概略断面図である。It is a schematic sectional drawing which shows a preferable example of the light diffusable polarizing plate of this invention. 光拡散フィルムを製造するための装置の一例を示す概略図である。It is the schematic which shows an example of the apparatus for manufacturing a light-diffusion film. 本発明の液晶表示装置の好ましい一例を示す概略断面図である。It is a schematic sectional drawing which shows a preferable example of the liquid crystal display device of this invention. 光拡散手段の一例を示す概略断面図である。It is a schematic sectional drawing which shows an example of a light-diffusion means. 光拡散手段の他の一例を示す概略断面図である。It is a schematic sectional drawing which shows another example of a light-diffusion means. ２枚の光偏向板（プリズムシート）が有する線状プリズムの稜線方向と、偏光板の透過軸方向との関係を説明するための概略斜視図である。It is a schematic perspective view for demonstrating the relationship between the ridgeline direction of the linear prism which two light deflection plates (prism sheet | seat) have, and the transmission-axis direction of a polarizing plate. 光拡散手段について、液晶セルの光入射面の垂線に対して７０°方向の輝度値を測定する方法の一例を示す図である。It is a figure which shows an example of the method of measuring the luminance value of a 70 degree direction with respect to the perpendicular of the light-incidence surface of a liquid crystal cell about a light-diffusion means. 非平行光の定義を説明する図である。It is a figure explaining the definition of non-parallel light. 本発明の液晶表示装置の他の好ましい一例を示す概略断面図である。It is a schematic sectional drawing which shows another preferable example of the liquid crystal display device of this invention.
　＜光拡散性偏光板＞
　図１は、本発明の光拡散性偏光板の好ましい例を示す概略断面図である。本発明に係る図１に示される光拡散性偏光板１００は、偏光フィルム１０１と、偏光フィルム１０１上に積層される光拡散フィルム１０２と、光拡散フィルム１０２上に積層される表面処理フィルム１０３とを備え、光拡散フィルム１０２は光拡散層１０６を有し、表面処理フィルム１０３は一方の表面に光学的処理が施された（具体的には、表面処理層１０８が付与された）透明樹脂フィルム１０７から形成され、光拡散フィルム１０２の光拡散層１０６と、表面処理フィルム１０３とが、粘着剤層または接着剤層１０４を介して互いに貼合されている。 <Light diffusing polarizing plate>
FIG. 1 is a schematic cross-sectional view showing a preferred example of the light diffusing polarizing plate of the present invention. A light diffusing polarizing plate 100 shown in FIG. 1 according to the present invention includes a polarizing film 101, a light diffusing film 102 laminated on the polarizing film 101, and a surface treatment film 103 laminated on the light diffusing film 102. The light diffusing film 102 has a light diffusing layer 106, and the surface-treated film 103 is optically treated on one surface (specifically, a surface-treated layer 108 is provided). The light diffusion layer 106 of the light diffusion film 102 and the surface treatment film 103 are bonded to each other via the pressure-sensitive adhesive layer or the adhesive layer 104.
　図１に示される光拡散性偏光板１００において、光拡散フィルム１０２は、透明基材フィルム１０５と、透明基材フィルム１０５上に積層される光拡散層１０６とを備えるものであり、光拡散層１０６は、透光性樹脂１０６ａ中に透光性微粒子１０６ｂが分散された樹脂層から構成される。光拡散フィルム１０２は、その透明基材フィルム１０５側が偏光フィルム１０１に対向するように、すなわち、透明基材フィルム１０５が光拡散層１０６よりも偏光フィルム１０１に近くなるように、偏光フィルム１０１上に積層される。光拡散フィルム１０２は、その光拡散層１０６の表面のうち、表面処理フィルム１０３に近い方の表面のＪＩＳ　Ｂ　０６０１に従う中心線平均粗さＲａが０．１μｍ以上１μｍ未満である。 In the light diffusing polarizing plate 100 shown in FIG. 1, the light diffusing film 102 includes a transparent base film 105 and a light diffusing layer 106 laminated on the transparent base film 105. Reference numeral 106 denotes a resin layer in which translucent fine particles 106b are dispersed in a translucent resin 106a. The light diffusing film 102 is placed on the polarizing film 101 so that the transparent base film 105 side faces the polarizing film 101, that is, the transparent base film 105 is closer to the polarizing film 101 than the light diffusing layer 106. Laminated. The light diffusing film 102 has a center line average roughness Ra according to JIS B 0601 on the surface closer to the surface treatment film 103 of the surface of the light diffusing layer 106 is 0.1 μm or more and less than 1 μm.
　表面処理フィルム１０３は、透明樹脂フィルム１０７と、透明樹脂フィルム１０７の一方の表面に積層される表面処理層１０８とを備える。表面処理フィルム１０３は、その透明樹脂フィルム１０７の表面処理層１０８とは反対側の面（表面処理フィルム１０３の表面のうち光学的処理が施されていない面）で、粘着剤層または接着剤層１０４を介して光拡散フィルム１０２の光拡散層１０６に貼合されている。 The surface treatment film 103 includes a transparent resin film 107 and a surface treatment layer 108 laminated on one surface of the transparent resin film 107. The surface treatment film 103 is a surface opposite to the surface treatment layer 108 of the transparent resin film 107 (the surface of the surface treatment film 103 that is not subjected to optical treatment), and is a pressure-sensitive adhesive layer or an adhesive layer. It is bonded to the light diffusion layer 106 of the light diffusion film 102 through 104.
　なお、保護フィルム１０９は、偏光フィルム１０１の他方の表面を保護するためのフィルムであるが、必ずしも必要ではなく省略されてもよい。また、保護フィルム１０９の代わりに、位相差フィルム（位相差板）等の光学補償フィルムなどが貼合されてもよい。 In addition, although the protective film 109 is a film for protecting the other surface of the polarizing film 101, it is not necessarily required and may be omitted. Further, instead of the protective film 109, an optical compensation film such as a retardation film (retardation plate) may be bonded.
　上記構成を有する本発明の光拡散性偏光板１００によれば、光拡散フィルム１０２の光拡散層１０６と、透明樹脂フィルム１０７上に表面処理層１０８を積層して形成した表面処理フィルム１０３とを、粘着剤層または接着剤層１０４を介して貼合するため、光拡散層１０６の表面に極端に大きな突起が形成される場合においても、すなわち、光拡散層１０６の表面の中心線平均粗さＲａが０．１μｍ以上である場合においても、光拡散層１０６上に所望の光学機能を有する表面処理フィルム１０３を確実に、しかも、光拡散層１０６の表面形状による表面処理層１０８の構造、形状への影響を完全に排除しつつ積層させることが可能となる。したがって、本発明の光拡散性偏光板１００は、光拡散機能とともに、表面処理層１０８による所定の光学機能を良好に示す。 According to the light diffusing polarizing plate 100 of the present invention having the above configuration, the light diffusing layer 106 of the light diffusing film 102 and the surface treated film 103 formed by laminating the surface treated layer 108 on the transparent resin film 107. Even when extremely large protrusions are formed on the surface of the light diffusing layer 106 for bonding via the pressure-sensitive adhesive layer or the adhesive layer 104, that is, the center line average roughness of the surface of the light diffusing layer 106. Even when Ra is 0.1 μm or more, the surface treatment film 103 having a desired optical function is reliably formed on the light diffusion layer 106, and the structure and shape of the surface treatment layer 108 by the surface shape of the light diffusion layer 106 It becomes possible to laminate the film while completely eliminating the influence on the film. Therefore, the light diffusing polarizing plate 100 of the present invention exhibits a predetermined optical function by the surface treatment layer 108 as well as a light diffusing function.
　以下、本発明の光拡散性偏光板について、さらに詳細に説明する。 Hereinafter, the light diffusable polarizing plate of the present invention will be described in more detail.
　（偏光フィルム）
　偏光フィルム１０１としては、たとえば、ポリビニルアルコール系樹脂、ポリ酢酸ビニル樹脂、エチレン／酢酸ビニル（ＥＶＡ）樹脂、ポリアミド樹脂、ポリエステル系樹脂等を含むフィルムに、二色性染料またはヨウ素を吸着配向させたもの、配向したポリビニルアルコールの二色性脱水生成物（ポリビニレン）の分子鎖を含有するポリビニルアルコール／ポリビニレンコポリマーを有する分子的に配向したポリビニルアルコールフィルム等が挙げられる。特に、一軸延伸されたポリビニルアルコール系樹脂フィルムに二色性染料またはヨウ素を吸着配向させたものが偏光フィルムとして好適に使用される。偏光フィルム１０１の厚さに特に制限はないが、光拡散性偏光板の薄型化等の観点から、１００μｍ以下が好ましく、より好ましくは１０～５０μｍ、さらに好ましくは２５～３５μｍである。 (Polarizing film)
As the polarizing film 101, for example, a dichroic dye or iodine is adsorbed and oriented on a film containing polyvinyl alcohol resin, polyvinyl acetate resin, ethylene / vinyl acetate (EVA) resin, polyamide resin, polyester resin, or the like. And a molecularly oriented polyvinyl alcohol film having a polyvinyl alcohol / polyvinylene copolymer containing a molecular chain of an oriented polyvinyl alcohol dichroic dehydration product (polyvinylene). In particular, a uniaxially stretched polyvinyl alcohol resin film obtained by adsorbing and orienting a dichroic dye or iodine is suitably used as a polarizing film. The thickness of the polarizing film 101 is not particularly limited, but is preferably 100 μm or less, more preferably 10 to 50 μm, still more preferably 25 to 35 μm from the viewpoint of reducing the thickness of the light diffusing polarizing plate.
　（光拡散フィルム）
　本発明で用いる光拡散フィルム１０２は、図１に示されるように透明基材フィルム１０５と、透明基材フィルム１０５上に積層される光拡散層１０６とを備え、光拡散層１０６が透光性樹脂１０６ａと、透光性樹脂１０６ａ中に分散された透光性微粒子（光拡散剤）１０６ｂと、から形成される樹脂層から構成されるものであることが好ましい。 (Light diffusion film)
As shown in FIG. 1, the light diffusion film 102 used in the present invention includes a transparent base film 105 and a light diffusion layer 106 laminated on the transparent base film 105, and the light diffusion layer 106 is translucent. It is preferably composed of a resin layer formed of a resin 106a and translucent fine particles (light diffusing agent) 106b dispersed in the translucent resin 106a.
　透明基材フィルム１０５としては、光学的に透明である限り特に制限されず、たとえばガラスやプラスチックフィルムなどを用いることができる。プラスチックフィルムとしては、適度の透明性、機械強度を有するものが好ましく、具体的には、ＴＡＣ（トリアセチルセルロース）等のセルロースアセテート系樹脂；アクリル系樹脂；ポリカーボネート樹脂；およびポリエチレンテレフタレート等のポリエステル系樹脂；などが挙げられる。透明基材フィルム１０５の厚さは、たとえば１０～５００μｍであり、好ましくは２０～３００μｍである。 The transparent substrate film 105 is not particularly limited as long as it is optically transparent, and for example, glass or plastic film can be used. The plastic film preferably has moderate transparency and mechanical strength. Specifically, cellulose acetate resins such as TAC (triacetyl cellulose); acrylic resins; polycarbonate resins; and polyesters such as polyethylene terephthalate Resin; and the like. The thickness of the transparent substrate film 105 is, for example, 10 to 500 μm, preferably 20 to 300 μm.
　光拡散層１０６は、透光性樹脂１０６ａを基材とする層であって、透光性樹脂１０６ａ中に透光性微粒子１０６ｂが分散されている。透光性樹脂１０６ａとしては、透光性を有するものであれば特に制限はなく、たとえば、紫外線硬化型樹脂、電子線硬化型樹脂などの電離放射線硬化型樹脂や熱硬化型樹脂の硬化物、熱可塑性樹脂の硬化物、金属アルコキシドの硬化物などを用いることができる。この中でも、高い硬度および耐擦傷性を付与できることから、電離放射線硬化型樹脂が好適である。電離放射線硬化型樹脂、熱硬化型樹脂または金属アルコキシドを用いる場合は、電離放射線の照射または加熱により当該樹脂を硬化させることにより透光性樹脂１０６ａが形成される。 The light diffusing layer 106 is a layer having a translucent resin 106a as a base material, and translucent fine particles 106b are dispersed in the translucent resin 106a. The translucent resin 106a is not particularly limited as long as it has translucency. For example, an ionizing radiation curable resin such as an ultraviolet curable resin or an electron beam curable resin or a cured product of a thermosetting resin, A cured product of a thermoplastic resin, a cured product of a metal alkoxide, or the like can be used. Among these, ionizing radiation curable resins are preferred because they can impart high hardness and scratch resistance. In the case of using an ionizing radiation curable resin, a thermosetting resin, or a metal alkoxide, the translucent resin 106a is formed by curing the resin by irradiation or heating with ionizing radiation.
　電離放射線硬化型樹脂としては、多価アルコールのアクリル酸またはメタクリル酸エステルのような多官能性のアクリレート；ジイソシアネートと、多価アルコールおよびアクリル酸またはメタクリル酸のヒドロキシエステル等と、から合成されるような多官能のウレタンアクリレート；などが挙げられる。また、これらの他にも、アクリレート系の官能基を有する、ポリエーテル樹脂；ポリエステル樹脂；エポキシ樹脂；アルキッド樹脂；スピロアセタール樹脂；ポリブタジエン樹脂；ポリチオールポリエン樹脂；等も使用することができる。 The ionizing radiation curable resin may be synthesized from polyfunctional acrylates such as polyhydric alcohol acrylic acid or methacrylic acid ester; diisocyanate, polyhydric alcohol and acrylic acid or methacrylic acid hydroxy ester, or the like. And polyfunctional urethane acrylates. Besides these, polyether resins having an acrylate functional group; polyester resins; epoxy resins; alkyd resins; spiroacetal resins; polybutadiene resins; polythiol polyene resins;
　熱硬化型樹脂としては、アクリルポリオールとイソシアネートプレポリマーとから調製される熱硬化型ウレタン樹脂のほか、フェノール樹脂、尿素メラミン樹脂、エポキシ樹脂、不飽和ポリエステル樹脂、シリコーン樹脂が挙げられる。 Examples of thermosetting resins include phenolic resins, urea melamine resins, epoxy resins, unsaturated polyester resins, and silicone resins, in addition to thermosetting urethane resins prepared from acrylic polyols and isocyanate prepolymers.
　熱可塑性樹脂としては、アセチルセルロース、ニトロセルロース、アセチルブチルセルロース、エチルセルロース、メチルセルロース等のセルロース誘導体；酢酸ビニルおよびその共重合体、塩化ビニルおよびその共重合体、塩化ビニリデンおよびその共重合体等のビニル系樹脂；ポリビニルホルマール、ポリビニルブチラール等のアセタール系樹脂；アクリル樹脂およびその共重合体、メタクリル樹脂およびその共重合体等のアクリル系樹脂；ポリスチレン系樹脂；ポリアミド系樹脂；ポリエステル系樹脂；ポリカーボネート系樹脂等が挙げられる。 Examples of thermoplastic resins include cellulose derivatives such as acetylcellulose, nitrocellulose, acetylbutylcellulose, ethylcellulose, and methylcellulose; vinyl acetate and copolymers thereof, vinyl chloride and copolymers thereof, vinylidene chloride and copolymers thereof, and the like. Acetal resins such as polyvinyl formal and polyvinyl butyral; Acrylic resins and copolymers thereof, Acrylic resins such as methacrylic resins and copolymers; Polystyrene resins; Polyamide resins; Polyester resins; Polycarbonate resins Etc.
　金属アルコキシドとしては、珪素アルコキシド系の材料を原料とする酸化珪素系マトリックス等を使用することができる。具体的には、テトラメトキシシラン、テトラエトキシシラン等であり、加水分解や脱水縮合により無機系または有機無機複合系マトリックス（透光性樹脂）とすることができる。 As the metal alkoxide, a silicon oxide matrix made of a silicon alkoxide material can be used. Specifically, it is tetramethoxysilane, tetraethoxysilane, or the like, and can be made into an inorganic or organic-inorganic composite matrix (translucent resin) by hydrolysis or dehydration condensation.
　また、透光性微粒子１０６ｂとしては、透光性を有する有機微粒子または無機微粒子から形成される光拡散剤を用いることができる。たとえば、アクリル樹脂、メラミン樹脂、ポリエチレン、ポリスチレン、有機シリコーン樹脂、アクリル－スチレン共重合体等から形成される有機微粒子や、炭酸カルシウム、シリカ、酸化アルミニウム、炭酸バリウム、硫酸バリウム、酸化チタン、ガラス等から形成される無機微粒子等が挙げられる。また、有機重合体のバルーンやガラス中空ビーズも使用できる。透光性微粒子１０６ｂは、１種類の微粒子から構成されていてもよいし、２種類以上の微粒子を含んでいてもよい。透光性微粒子１０６ｂの形状は、球状、扁平状、板状、針状、不定形状等いずれの形状であってもよいが、球状または略球状が好ましい。 Further, as the light-transmitting fine particles 106b, a light diffusing agent formed from light-transmitting organic fine particles or inorganic fine particles can be used. For example, organic fine particles formed from acrylic resin, melamine resin, polyethylene, polystyrene, organic silicone resin, acrylic-styrene copolymer, calcium carbonate, silica, aluminum oxide, barium carbonate, barium sulfate, titanium oxide, glass, etc. Inorganic fine particles formed from the above. Organic polymer balloons and glass hollow beads can also be used. The translucent fine particles 106b may be composed of one kind of fine particles, or may contain two or more kinds of fine particles. The shape of the translucent fine particles 106b may be any shape such as a spherical shape, a flat shape, a plate shape, a needle shape, and an indefinite shape, but a spherical shape or a substantially spherical shape is preferable.
　透光性微粒子１０６ｂの重量平均粒径は、０．５～１５μｍであることが好ましく、３～８μｍであることがより好ましい。透光性微粒子１０６ｂの重量平均粒径が０．５μｍ未満であると、光拡散フィルム１０２の光拡散性が不十分となり、その結果、液晶表示装置に光拡散性偏光板１００を適用した際に、十分な広視野角性能が得られない場合がある。また、重量平均粒径が１５μｍを超える場合、光拡散フィルム１０２が十分な光拡散性を得られない場合がある。また、透光性微粒子１０６ｂは、その粒径の標準偏差の重量平均粒径に対する比（標準偏差／重量平均粒径）が０．５以下であることが好ましく、０．４以下であることがより好ましい。当該比が０．５を超える場合、粒径が極端に大きい透光性微粒子が含まれるようになり、その結果、光拡散層の中心線平均粗さＲａが１μｍ以上となり、好ましい範囲から逸脱したりする場合がある。なお、透光性微粒子１０６ｂの重量平均粒径および粒径の標準偏差は、コールター原理（細孔電気抵抗法）に基づき、コールターマルチサイザー（ベックマンコールター社製）を用いて測定される。 The weight average particle diameter of the translucent fine particles 106b is preferably 0.5 to 15 μm, and more preferably 3 to 8 μm. When the weight average particle diameter of the light transmitting fine particles 106b is less than 0.5 μm, the light diffusing property of the light diffusing film 102 becomes insufficient. As a result, when the light diffusing polarizing plate 100 is applied to the liquid crystal display device. In some cases, sufficient wide viewing angle performance cannot be obtained. Further, when the weight average particle diameter exceeds 15 μm, the light diffusion film 102 may not obtain sufficient light diffusibility. The ratio of the standard deviation of the particle diameter to the weight average particle diameter (standard deviation / weight average particle diameter) of the light transmitting fine particles 106b is preferably 0.5 or less, and is preferably 0.4 or less. More preferred. When the ratio exceeds 0.5, translucent fine particles having an extremely large particle diameter are included, and as a result, the center line average roughness Ra of the light diffusion layer is 1 μm or more, which deviates from the preferred range. Sometimes. The weight average particle diameter and the standard deviation of the particle diameter of the translucent fine particles 106b are measured using a Coulter Multisizer (manufactured by Beckman Coulter, Inc.) based on the Coulter principle (pore electrical resistance method).
　光拡散層１０６における透光性微粒子１０６ｂの含有量は、透光性樹脂１０６ａの１００重量部に対して２０重量部以上１００重量部以下であることが好ましい。本発明においては、このように比較的多量の透光性微粒子（光拡散剤）１０６ｂを光拡散層１０６に含有させる場合においても、表面処理フィルム１０３を粘着剤層または接着剤層１０４を介して光拡散層１０６に貼合することにより、表面処理層１０８の形成に困難を伴うことはない。すなわち、表面処理層１０８を確実かつ容易に、しかも表面処理層１０８が所定の光学機能を発現するために必要な構造や形状を損なうことなく、表面処理層１０８を光拡散性偏光板１００に付与することができる。光拡散層１０６における透光性微粒子１０６ｂの含有量は、透光性樹脂１０６ａの１００重量部に対して、より好ましくは２０重量部以上７０重量部以下、さらに好ましくは２５重量部以上６０重量部以下、特に好ましくは３０重量部以上５５重量部以下である。透光性微粒子１０６ｂの含有量が透光性樹脂１００重量部に対して２０重量部未満であると、光拡散フィルム１０２の光拡散性が不十分となり、その結果、液晶表示装置に光拡散性偏光板を適用した際に、十分な広視野角性能が得られにくい。また、透光性微粒子１０６ｂの含有量が透光性樹脂１００重量部に対して１００重量部を超えると、光拡散フィルム１０２のヘイズが過度に大きくなる結果、光拡散フィルム１０２の透明性が低下し、液晶表示装置に光拡散性偏光板を適用した際に、正面コントラストの低下を招く。 The content of the light-transmitting fine particles 106b in the light diffusion layer 106 is preferably 20 parts by weight or more and 100 parts by weight or less with respect to 100 parts by weight of the light-transmitting resin 106a. In the present invention, even when a relatively large amount of light-transmitting fine particles (light diffusing agent) 106b is contained in the light diffusing layer 106 in this way, the surface treatment film 103 is interposed between the pressure-sensitive adhesive layer or the adhesive layer 104. By bonding to the light diffusion layer 106, there is no difficulty in forming the surface treatment layer 108. That is, the surface treatment layer 108 is applied to the light diffusing polarizing plate 100 reliably and easily and without impairing the structure and shape necessary for the surface treatment layer 108 to exhibit a predetermined optical function. can do. The content of the light transmissive fine particles 106b in the light diffusion layer 106 is more preferably 20 parts by weight or more and 70 parts by weight or less, and further preferably 25 parts by weight or more and 60 parts by weight or less with respect to 100 parts by weight of the light transmissive resin 106a. Hereinafter, it is particularly preferably 30 parts by weight or more and 55 parts by weight or less. When the content of the light transmissive fine particles 106b is less than 20 parts by weight with respect to 100 parts by weight of the light transmissive resin, the light diffusing film 102 has insufficient light diffusibility. When a polarizing plate is applied, sufficient wide viewing angle performance is difficult to obtain. Further, when the content of the light transmissive fine particles 106b exceeds 100 parts by weight with respect to 100 parts by weight of the light transmissive resin, the haze of the light diffusing film 102 becomes excessively large, resulting in a decrease in transparency of the light diffusing film 102. However, when a light diffusing polarizing plate is applied to the liquid crystal display device, the front contrast is lowered.
　透光性微粒子１０６ｂと透光性樹脂１０６ａとの屈折率差は、０．０４から０．１５の範囲であることが好ましい。透光性微粒子１０６ｂと透光性樹脂１０６ａとの屈折率差を上記範囲内とすることによって、透光性微粒子１０６ｂと透光性樹脂１０６ａとの屈折率差による適度な内部散乱が生じ、光拡散性が適度に高い光拡散フィルム１０２を得ることができる。 The difference in refractive index between the translucent fine particles 106b and the translucent resin 106a is preferably in the range of 0.04 to 0.15. By setting the refractive index difference between the translucent fine particles 106b and the translucent resin 106a within the above range, appropriate internal scattering occurs due to the refractive index difference between the translucent fine particles 106b and the translucent resin 106a. The light diffusion film 102 having a moderately high diffusibility can be obtained.
　また、光拡散層１０６の表面（透明基材フィルム１０５とは反対側の表面、すなわち、光拡散層１０６の表面のうち表面処理フィルム１０３に近い方の表面）は、透光性樹脂１０６ａのみによって形成されていることが好ましい。すなわち、透光性微粒子１０６ｂは、光拡散層１０６の上記表面から突出しておらず、完全に光拡散層１０６内に埋没していることが好ましい。このために、光拡散層１０６の厚さは、透光性微粒子１０６ｂの重量平均粒径に対して１倍以上３倍以下であることが好ましい。光拡散層１０６の厚さが、透光性微粒子１０６ｂの重量平均粒径の１倍未満である場合、液晶表示装置に光拡散性偏光板１００を適用した際に、光拡散層１０６の表面が粗くなりすぎるため、表面処理フィルム貼合時に気泡噛み込み等の不具合を生じる場合がある。また、光拡散層１０６の厚さが透光性微粒子１０６ｂの重量平均粒径の３倍を超える場合、光拡散層１０６の厚さが大きくなり過ぎ、それに伴い光拡散フィルム１０２の光拡散性が強くなり過ぎるため、その結果、液晶表示装置に光拡散性偏光板１００を適用した際に、正面コントラストが低下する場合がある。なお、本明細書において、「光拡散層の厚さ」とは、光拡散層１０６の透明基材フィルム１０５に近い側の面から反対側の面までの最大厚みのことを指す。したがって、本発明の光拡散フィルム１０２において、図１に示すＡに相当する最も厚い部分が光拡散層１０６の厚さとなる。光拡散層１０６の透明基材フィルム１０５に近い側の面から反対側の面までの厚みが最大でない部分（例えば、凹凸を有するフィルムの凹部分）においては、光拡散層１０６の厚さは透光性微粒子１０６ｂの重量平均粒径の１倍以上でなくてもよい。 Further, the surface of the light diffusion layer 106 (the surface opposite to the transparent base film 105, that is, the surface closer to the surface treatment film 103 among the surfaces of the light diffusion layer 106) is formed only by the translucent resin 106a. Preferably it is formed. That is, it is preferable that the translucent fine particles 106 b do not protrude from the surface of the light diffusion layer 106 and are completely buried in the light diffusion layer 106. Therefore, the thickness of the light diffusion layer 106 is preferably 1 to 3 times the weight average particle diameter of the translucent fine particles 106b. When the thickness of the light diffusing layer 106 is less than 1 times the weight average particle diameter of the light transmissive fine particles 106b, the surface of the light diffusing layer 106 is formed when the light diffusing polarizing plate 100 is applied to the liquid crystal display device. Since it becomes too coarse, problems, such as air bubble biting, may occur during surface treatment film bonding. Further, when the thickness of the light diffusion layer 106 exceeds three times the weight average particle diameter of the translucent fine particles 106b, the thickness of the light diffusion layer 106 becomes too large, and the light diffusion property of the light diffusion film 102 is accordingly increased. As a result, when the light diffusing polarizing plate 100 is applied to the liquid crystal display device, the front contrast may be lowered. In this specification, “the thickness of the light diffusion layer” refers to the maximum thickness from the surface of the light diffusion layer 106 closer to the transparent base film 105 to the opposite surface. Therefore, in the light diffusion film 102 of the present invention, the thickest portion corresponding to A shown in FIG. In the portion where the thickness from the surface near the transparent base film 105 to the opposite surface of the light diffusion layer 106 is not the maximum (for example, the concave portion of the film having unevenness), the thickness of the light diffusion layer 106 is transparent. It may not be 1 or more times the weight average particle diameter of the light-sensitive fine particles 106b.
　光拡散層１０６の厚さは、１～３０μｍの範囲が好ましい。光拡散層１０６の厚さが１μｍ未満の場合、液晶表示装置の視認側表面に配置される光拡散フィルム１０２に要求される十分な耐擦傷性が付与されない場合がある。また、厚さが３０μｍを超える場合、作製した光拡散フィルム１０２に発生するカールの量が大きくなり、光拡散性偏光板１００の製造プロセスにおける取り扱い性が悪くなる。 The thickness of the light diffusion layer 106 is preferably in the range of 1 to 30 μm. When the thickness of the light diffusion layer 106 is less than 1 μm, sufficient scratch resistance required for the light diffusion film 102 disposed on the viewing side surface of the liquid crystal display device may not be provided. On the other hand, when the thickness exceeds 30 μm, the amount of curl generated in the produced light diffusing film 102 becomes large, and the handleability in the manufacturing process of the light diffusing polarizing plate 100 is deteriorated.
　光拡散層１０６の表面（透明基材フィルム１０５とは反対側の表面、すなわち、光拡散層１０６の表面のうち表面処理フィルム１０３に近い方の表面）のＪＩＳ　Ｂ　０６０１に従う中心線平均粗さＲａは０．１μｍ以上１μｍ未満であり、好ましくは、０．２μｍ以上０．５μｍ未満である。光拡散層１０６表面の中心線平均粗さＲａが１μｍ以上の場合、表面処理フィルム貼合時に気泡噛み込み等の不具合を生じる場合がある。本発明によれば、光拡散層１０６の表面に極端に大きな突起が形成される場合であっても、すなわち、中心線平均粗さＲａが０．１μｍ以上、さらには、０．２μｍ以上であっても、良好な光学機能を示す表面処理層を光拡散性偏光板に付与することができる。ＪＩＳ　Ｂ　０６０１に従う中心線平均粗さＲａとは、粗さ曲線からその中心線の方向に基準長さｌ（エル）だけを抜き取り、この抜き取り部分の中心線の方向にｘ軸を、縦倍率の方向にｙ軸をとり、粗さ曲線をＹ＝ｆ（ｘ）で表したときに、下記式（１）：
Figure JPOXMLDOC01-appb-M000001
 によって求められる値をマイクロメートル（μｍ）単位で表したものをいう。中心線平均粗さＲａは、ＪＩＳ　Ｂ　０６０１に準拠した共焦点干渉顕微鏡（たとえば、株式会社オプティカルソリューション社製の「ＰＬμ２３００」）を用いて上記計算式（１）に基づいてＲａを計算できるプログラムソフトにより算出することができる。
　なお、本発明の光拡散性偏光板１００においては、光拡散層１０６の表面のうち、表面処理フィルム１０３に近い方の表面の中心線平均粗さＲａが０．１μｍ以上１μｍ未満であればよく、光拡散層１０６が透光性樹脂１０６ｂまたは透光性微粒子１０６ａを含有していなくてもよい。 Centerline average roughness Ra according to JIS B 0601 of the surface of the light diffusion layer 106 (the surface opposite to the transparent base film 105, ie, the surface of the light diffusion layer 106 closer to the surface treatment film 103) Is 0.1 μm or more and less than 1 μm, preferably 0.2 μm or more and less than 0.5 μm. When the center line average roughness Ra on the surface of the light diffusion layer 106 is 1 μm or more, there may be a problem such as air bubble biting when the surface treatment film is bonded. According to the present invention, even when extremely large protrusions are formed on the surface of the light diffusion layer 106, that is, the center line average roughness Ra is 0.1 μm or more, and further 0.2 μm or more. However, the surface treatment layer showing a good optical function can be imparted to the light diffusing polarizing plate. The centerline average roughness Ra according to JIS B 0601 means that only the reference length l (el) is extracted from the roughness curve in the direction of the centerline, the x-axis is extracted in the direction of the centerline of the extracted portion, When the y-axis is taken in the direction and the roughness curve is represented by Y = f (x), the following formula (1):
Figure JPOXMLDOC01-appb-M000001
 Is a value expressed in units of micrometers (μm). Centerline average roughness Ra is a program software that can calculate Ra based on the above formula (1) using a confocal interference microscope (for example, “PLμ2300” manufactured by Optical Solution Co., Ltd.) in accordance with JIS B 0601. Can be calculated.
In the light diffusing polarizing plate 100 of the present invention, it is only necessary that the center line average roughness Ra of the surface of the light diffusing layer 106 closer to the surface treatment film 103 is 0.1 μm or more and less than 1 μm. The light diffusion layer 106 may not contain the light-transmitting resin 106b or the light-transmitting fine particles 106a.
　光拡散フィルム１０２は、全ヘイズが３０％以上７０％以下であり、かつ内部ヘイズが３０％以上７０％以下であることが好ましい。「全ヘイズ」とは、光拡散フィルム１０２に光を照射して透過した光線の全量を表す全光線透過率（Ｔｔ）と、光拡散フィルム１０２により拡散されて透過した拡散光線透過率（Ｔｄ）との比から下式（２）：
　全ヘイズ（％）＝（Ｔｄ／Ｔｔ）×１００　　　　（２）
により求められる。 The light diffusion film 102 preferably has a total haze of 30% to 70% and an internal haze of 30% to 70%. “Total haze” means the total light transmittance (Tt) representing the total amount of light transmitted through the light diffusing film 102 and the diffused light transmittance (Td) diffused and transmitted by the light diffusing film 102. From the ratio to the following formula (2):
Total haze (%) = (Td / Tt) × 100 (2)
It is calculated by.
　全光線透過率（Ｔｔ）は、入射光と同軸のまま透過した平行光線透過率（Ｔｐ）と拡散光線透過率（Ｔｄ）の和である。全光線透過率（Ｔｔ）および拡散光線透過率（Ｔｄ）は、ＪＩＳ　Ｋ　７３６１に準拠して測定される値である。 The total light transmittance (Tt) is the sum of the parallel light transmittance (Tp) and the diffuse light transmittance (Td) that are transmitted coaxially with the incident light. The total light transmittance (Tt) and the diffused light transmittance (Td) are values measured in accordance with JIS K 7361.
　また、光拡散フィルム１０２の「内部ヘイズ」とは、全ヘイズのうち、光拡散層１０６の表面のうち光出射面側の面の表面形状に起因するヘイズ（表面ヘイズ）以外のヘイズである。 The “internal haze” of the light diffusing film 102 is a haze other than the haze (surface haze) due to the surface shape of the light emitting surface side of the surface of the light diffusing layer 106 among all the hazes.
　全ヘイズおよび／または内部ヘイズが３０％未満の場合、光散乱性が不十分であり、十分な広視野角性能が得られにくい。また、全ヘイズおよび／または内部ヘイズが７０％を超える場合は、光散乱が強くなり、液晶表示装置に光拡散性偏光板１００を適用した際に、正面コントラストが低下する場合がある。また、全ヘイズおよび／または内部ヘイズが７０％を超える場合は、光拡散フィルム１０２の透明性が損なわれる傾向にある。全ヘイズおよび内部ヘイズはそれぞれ、３５％以上６５％以下であることがより好ましい。 When the total haze and / or internal haze is less than 30%, the light scattering property is insufficient, and it is difficult to obtain sufficient wide viewing angle performance. Moreover, when the total haze and / or internal haze exceeds 70%, light scattering becomes strong, and when the light diffusing polarizing plate 100 is applied to the liquid crystal display device, the front contrast may be lowered. Further, when the total haze and / or internal haze exceeds 70%, the transparency of the light diffusion film 102 tends to be impaired. More preferably, the total haze and the internal haze are 35% or more and 65% or less, respectively.
　光拡散フィルム１０２の全ヘイズ、内部ヘイズおよび表面ヘイズは、具体的には次のようにして測定される。すなわち、まず、フィルムの反りを防止するため、光学的に透明な粘着剤を用いて光拡散フィルム１０２を、光拡散層１０６が表面となるように、透明基材フィルム１０５側の面をガラス基板に貼合して測定用サンプルを作製し、当該測定用サンプルについて全ヘイズ値を測定する。全ヘイズ値は、ＪＩＳ　Ｋ　７１３６に準拠したヘイズ透過率計（たとえば、株式会社村上色彩技術研究所製のヘイズメーター「ＨＭ－１５０」）を用いて、全光線透過率（Ｔｔ）および拡散光線透過率（Ｔｄ）を測定し、上記式（２）によって算出される。 The total haze, internal haze, and surface haze of the light diffusion film 102 are specifically measured as follows. That is, first, in order to prevent warping of the film, the surface of the transparent base film 105 side is a glass substrate so that the light diffusion film 102 becomes the surface using an optically transparent adhesive. The sample for measurement is produced by pasting together, and the total haze value of the sample for measurement is measured. For the total haze value, the total light transmittance (Tt) and diffuse light transmittance are measured using a haze transmittance meter (for example, a haze meter “HM-150” manufactured by Murakami Color Research Laboratory Co., Ltd.) in accordance with JIS K 7136. The rate (Td) is measured and calculated by the above equation (2).
　ついで、光拡散層１０６の表面に、ヘイズがほぼ０％であるトリアセチルセルロースフィルムを、グリセリンを用いて貼合し、上述の全ヘイズの測定と同様にしてヘイズを測定する。当該ヘイズは、光拡散層１０６の表面のうち光出射面側の面の表面形状に起因する表面ヘイズが、貼合されたトリアセチルセルロースフィルムによってほぼ打ち消されていることから、光拡散フィルム１０２の「内部ヘイズ」とみなすことができる。したがって、光拡散フィルム１０２の「表面ヘイズ」は、下記式（３）：
　表面ヘイズ（％）＝全ヘイズ（％）－内部ヘイズ（％）　　　　　　（３）
より求められる。 Next, a triacetyl cellulose film having a haze of approximately 0% is bonded to the surface of the light diffusion layer 106 using glycerin, and the haze is measured in the same manner as the measurement of the total haze described above. Since the surface haze caused by the surface shape of the light-emitting surface side of the surface of the light diffusion layer 106 is almost canceled by the bonded triacetyl cellulose film, the haze of the light diffusion film 102 It can be regarded as “internal haze”. Therefore, the “surface haze” of the light diffusion film 102 is expressed by the following formula (3):
Surface haze (%) = Total haze (%)-Internal haze (%) (3)
More demanded.
　なお、光拡散フィルム１０２は、透明基材フィルム１０５と光拡散層１０６との間に他の層（接着剤層を含む）を有していてもよい。 The light diffusion film 102 may have another layer (including an adhesive layer) between the transparent base film 105 and the light diffusion layer 106.
　次に、光拡散フィルム１０２を製造するための方法について説明する。光拡散フィルム１０２は、透明基材フィルム１０５上に、透光性微粒子１０６ｂが分散された樹脂液を塗布する工程を含む方法により形成することができる。 Next, a method for manufacturing the light diffusion film 102 will be described. The light diffusion film 102 can be formed by a method including a step of applying a resin liquid in which the translucent fine particles 106b are dispersed on the transparent base film 105.
　上記樹脂液は、透光性微粒子１０６ｂ、光拡散層１０６を構成する透光性樹脂１０６ａまたはこれを形成する樹脂（たとえば、電離放射線硬化型樹脂、熱硬化型樹脂、熱可塑性樹脂または金属アルコキシド）、および必要に応じて溶媒等のその他の成分を含む。透光性樹脂１０６ａを形成する樹脂として紫外線硬化型樹脂を用いる場合、上記樹脂液は、光重合開始剤（ラジカル重合開始剤）を含む。光重合開始剤としては、たとえば、アセトフェノン系光重合開始剤、ベンゾイン系光重合開始剤、ベンゾフェノン系光重合開始剤、チオキサントン系光重合開始剤、トリアジン系光重合開始剤、オキサジアゾール系光重合開始剤などが用いられる。また、光重合開始剤として、たとえば、２，４，６－トリメチルベンゾイルジフェニルホスフィンオキサイド、２，２’－ビス（ｏ－クロロフェニル）－４，４’，５，５’－テトラフェニル－１，２’－ビスイミダゾール、１０－ブチル－２－クロロアクリドン、２－エチルアントラキノン、ベンジル、９，１０－フェナンスレンキノン、カンファーキノン、フェニルグリオキシル酸メチル、チタノセン化合物等も用いることができる。 The resin liquid is a translucent fine particle 106b, a translucent resin 106a constituting the light diffusion layer 106, or a resin forming the same (for example, ionizing radiation curable resin, thermosetting resin, thermoplastic resin, or metal alkoxide). And other components such as a solvent as necessary. In the case where an ultraviolet curable resin is used as the resin forming the translucent resin 106a, the resin liquid includes a photopolymerization initiator (radical polymerization initiator). Examples of the photopolymerization initiator include acetophenone photopolymerization initiator, benzoin photopolymerization initiator, benzophenone photopolymerization initiator, thioxanthone photopolymerization initiator, triazine photopolymerization initiator, and oxadiazole photopolymerization initiator. An initiator or the like is used. Examples of the photopolymerization initiator include 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,2′-bis (o-chlorophenyl) -4,4 ′, 5,5′-tetraphenyl-1,2 '-Bisimidazole, 10-butyl-2-chloroacridone, 2-ethylanthraquinone, benzyl, 9,10-phenanthrenequinone, camphorquinone, methyl phenylglyoxylate, titanocene compounds and the like can also be used.
　光重合開始剤の使用量は、通常、樹脂液に含有される樹脂１００重量部に対して０．５～２０重量部であり、好ましくは、１～５重量部である。なお、光拡散フィルム１０２の光学特性および表面形状を均質なものとするために、樹脂溶液中の透光性微粒子１０６ｂの分散は等方分散であることが好ましい。 The amount of the photopolymerization initiator used is usually 0.5 to 20 parts by weight, preferably 1 to 5 parts by weight with respect to 100 parts by weight of the resin contained in the resin liquid. In order to make the optical properties and the surface shape of the light diffusion film 102 uniform, the dispersion of the light-transmitting fine particles 106b in the resin solution is preferably isotropic dispersion.
　透明基材フィルム１０５上への上記樹脂液の塗布は、たとえば、グラビアコート法、マイクログラビアコート法、ロッドコート法、ナイフコート法、エアーナイフコート法、キスコート法、ダイコート法などによって行なうことができる。樹脂液の塗布にあたっては、上述のように、光拡散層１０６の厚さが、透光性微粒子１０６ｂの重量平均粒径に対して１倍以上３倍以下となるように、塗布膜厚を調整することが好ましい。 Application of the resin liquid onto the transparent substrate film 105 can be performed, for example, by a gravure coating method, a micro gravure coating method, a rod coating method, a knife coating method, an air knife coating method, a kiss coating method, a die coating method, or the like. . When applying the resin liquid, as described above, the coating film thickness is adjusted so that the thickness of the light diffusion layer 106 is 1 to 3 times the weight average particle diameter of the translucent fine particles 106b. It is preferable to do.
　樹脂液の塗布性の改良または光拡散層１０６との接着性の改良を目的として、透明基材フィルム１０５の表面（光拡散層１０６側の表面）には、各種表面処理を施してもよい。表面処理としては、コロナ放電処理、グロー放電処理、酸表面処理、アルカリ表面処理、紫外線照射処理などが挙げられる。また、透明基材フィルム１０５上に、たとえばプライマー層（易接着層）等の他の層を形成し、この他の層の上に、樹脂液を塗布するようにしてもよい。 Various surface treatments may be applied to the surface of the transparent base film 105 (the surface on the light diffusion layer 106 side) for the purpose of improving the coating property of the resin liquid or improving the adhesion with the light diffusion layer 106. Examples of the surface treatment include corona discharge treatment, glow discharge treatment, acid surface treatment, alkali surface treatment, and ultraviolet irradiation treatment. Further, another layer such as a primer layer (easy adhesion layer) may be formed on the transparent base film 105, and the resin liquid may be applied on the other layer.
　また、透明基材フィルム１０５と偏光フィルム１０１との接着性を向上させるために、透明基材フィルム１０５の光拡散層１０６側の表面とは反対側の表面に、上記したような表面処理を施すことが好ましい。 In order to improve the adhesion between the transparent substrate film 105 and the polarizing film 101, the surface of the transparent substrate film 105 opposite to the surface on the light diffusion layer 106 side is subjected to the surface treatment as described above. It is preferable.
　光拡散フィルム１０２は、透明基材フィルム１０５上に、透光性微粒子１０６ｂが分散された樹脂液を塗布する工程と、樹脂液から形成された層の表面に、金型の鏡面または凹凸面を転写する工程とを含む方法によっても形成することができる。すなわち、上記中心線平均粗さＲａを有する光拡散層１０６は、上記樹脂液を塗布し、当該樹脂液から形成された層の表面に、必要に応じて鏡面を有する金型（鏡面金型）の当該鏡面または凹凸面を有する金型（エンボス加工用金型）の当該凹凸面を密着させて、鏡面または凹凸面を転写することにより形成することができる。鏡面金型は鏡面金属製ロールでもよく、また、エンボス加工用金型はエンボス加工用金属製ロールでもよい。 The light diffusing film 102 includes a step of applying a resin liquid in which translucent fine particles 106b are dispersed on a transparent base film 105, and a mirror surface or an uneven surface of a mold on the surface of a layer formed from the resin liquid. It can also be formed by a method including a transfer step. That is, the light diffusing layer 106 having the center line average roughness Ra is a mold (mirror mold) having a mirror surface on the surface of the layer formed from the resin liquid, if necessary. It can be formed by closely contacting the uneven surface of a mold having a mirror surface or an uneven surface (embossing mold) and transferring the mirror surface or the uneven surface. The mirror surface mold may be a mirror surface metal roll, and the embossing mold may be an embossing metal roll.
　透光性樹脂１０６ａを形成する樹脂として電離放射線硬化型樹脂、熱硬化型樹脂、熱可塑性樹脂または金属アルコキシドを用いる場合は、上記樹脂液からなる層を形成し、必要により乾燥（溶媒の除去）を行ない、必要に応じてその樹脂液からなる層の表面に金型の鏡面または凹凸面を密着させた状態でまたは密着させた後、電離放射線の照射（電離放射線硬化型樹脂を用いる場合）、加熱（熱硬化型樹脂または金属アルコキシドを用いる場合）または冷却（熱可塑性樹脂を用いる場合）により樹脂液からなる層を硬化させる。電離放射線としては、樹脂液に含まれる樹脂の種類に応じて紫外線、電子線、近紫外線、可視光線、近赤外線、赤外線、Ｘ線などから適宜選択することができるが、これらの中で紫外線、電子線が好ましく、特に取り扱いが簡便で高エネルギーが得られることから紫外線が好ましい。 When an ionizing radiation curable resin, thermosetting resin, thermoplastic resin or metal alkoxide is used as the resin for forming the translucent resin 106a, a layer made of the resin liquid is formed and dried (removal of the solvent) as necessary. If necessary, with the mirror surface or uneven surface of the mold in close contact with the surface of the layer made of the resin liquid, irradiation with ionizing radiation (when using ionizing radiation curable resin), The layer made of the resin liquid is cured by heating (when using a thermosetting resin or metal alkoxide) or cooling (when using a thermoplastic resin). The ionizing radiation can be appropriately selected from ultraviolet rays, electron beams, near ultraviolet rays, visible rays, near infrared rays, infrared rays, X-rays, etc. depending on the type of resin contained in the resin liquid. Among these, ultraviolet rays, An electron beam is preferable, and ultraviolet rays are particularly preferable because of easy handling and high energy.
　紫外線の光源としては、たとえば、低圧水銀灯、中圧水銀灯、高圧水銀灯、超高圧水銀灯、カーボンアーク灯、メタルハライドランプ、キセノンランプ等を用いることができる。また、ＡｒＦエキシマレーザー、ＫｒＦエキシマレーザー、エキシマランプまたはシンクロトロン放射光等も用いることができる。これらの中でも、超高圧水銀灯、高圧水銀灯、低圧水銀灯、キセノンランプ、メタルハライドランプが好ましく用いられる。 As the ultraviolet light source, for example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, or the like can be used. An ArF excimer laser, a KrF excimer laser, an excimer lamp, synchrotron radiation, or the like can also be used. Among these, an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a xenon lamp, and a metal halide lamp are preferably used.
　また、電子線としては、コックロフトワルトン型、バンデグラフ型、共振変圧型、絶縁コア変圧型、直線型、ダイナミトロン型、高周波型等の各種電子線加速器から放出される５０～１０００ｋｅＶ、好ましくは１００～３００ｋｅＶのエネルギーを有する電子線を挙げることができる。 As the electron beam, 50 to 1000 keV emitted from various electron beam accelerators such as Cockloft Walton type, Bande graph type, resonance transformation type, insulation core transformation type, linear type, dynamitron type, and high frequency type, preferably 100 Mention may be made of electron beams having an energy of ˜300 keV.
　次に、光拡散フィルム１０２を製造するための好ましい実施形態について説明する。当該好ましい実施形態に係る製造方法は、光拡散フィルム１０２を連続的に製造するために、ロール状に巻き付けられた透明基材フィルム１０５を連続的に送り出す工程、透光性微粒子１０６ｂが分散された樹脂液を塗布し、必要に応じて乾燥させる工程、樹脂液から形成された層を硬化させる工程、および、得られた光拡散フィルム１０２を巻き取る工程を含む。かかる製造方法は、たとえば図２に示される製造装置を用いて実施することができる。 Next, a preferred embodiment for manufacturing the light diffusion film 102 will be described. In the manufacturing method according to the preferred embodiment, in order to continuously manufacture the light diffusing film 102, the step of continuously feeding the transparent base film 105 wound in a roll shape, the translucent fine particles 106b are dispersed. It includes a step of applying a resin liquid and drying it as necessary, a step of curing a layer formed from the resin liquid, and a step of winding up the obtained light diffusion film 102. Such a manufacturing method can be implemented, for example, using a manufacturing apparatus shown in FIG.
　まず、巻き出し装置３０１により透明基材フィルム１０５が連続的に巻き出される。ついで、巻き出された透明基材フィルム１０５上に、塗工装置３０２およびこれに対向するバックアップロール３０３を使用して、透光性微粒子１０６ｂが分散された樹脂液が塗工される。次に、樹脂液に溶媒が含まれる場合には、樹脂液が塗工された透明基材フィルム１０５を乾燥機３０４を通過させることにより乾燥させる。次に、樹脂液から形成された層が設けられた透明基材フィルム１０５は、鏡面金属製ロールまたはエンボス加工用金属製ロール３０５とニップロール３０６との間へ、その樹脂液から形成された層が鏡面金属製ロールまたはエンボス加工用金属製ロール３０５と密着するように巻き出される。これにより、樹脂液から形成された層の表面に鏡面金属製ロールの鏡面またはエンボス加工用金属製ロールの凹凸面が転写される。ついで、透明基材フィルム１０５上の樹脂液から形成された層が鏡面金属製ロールまたはエンボス加工用金属製ロール３０５に密着した状態で、透明基材フィルム１０５を通して、紫外線照射装置３０８から紫外線を照射することにより、樹脂液から形成された層を硬化させて光拡散層１０６を形成する。紫外線照射により照射面が高温になることから、鏡面金属製ロールまたはエンボス加工用金属製ロール３０５は、その表面温度を室温～８０℃程度に調整するための冷却装置をその内部に備えることが好ましい。また、紫外線照射装置３０８は、１機、もしくは複数機を使用することができる。光拡散層１０６が形成された透明基材フィルム１０５（光拡散フィルム１０２）は、剥離ロール３０７によって、鏡面金属製ロールまたはエンボス加工用金属製ロール３０５から剥離される。以上のようにして製造された光拡散フィルム１０２は、巻き取り装置３０９へ巻き取られる。この際、光拡散層１０６を保護する目的で、光拡散層１０６表面に、再剥離性を有した粘着剤層を介してポリエチレンテレフタレートやポリエチレン等から形成される表面保護フィルムを貼着しながら光拡散フィルム１０２を巻き取ってもよい。 First, the transparent base film 105 is continuously unwound by the unwinding device 301. Next, a resin liquid in which the translucent fine particles 106 b are dispersed is applied onto the unwound transparent base film 105 using the coating device 302 and the backup roll 303 facing the coating device 302. Next, when the solvent is contained in the resin liquid, the transparent substrate film 105 coated with the resin liquid is dried by passing it through the dryer 304. Next, the transparent base film 105 provided with the layer formed from the resin liquid is formed between the mirror-made metal roll or the embossing metal roll 305 and the nip roll 306, and the layer formed from the resin liquid is It is unwound so as to be in close contact with the mirror surface metal roll or the embossing metal roll 305. Thereby, the mirror surface of the mirror surface metal roll or the uneven surface of the metal roll for embossing is transferred to the surface of the layer formed from the resin liquid. Next, ultraviolet rays are irradiated from the ultraviolet irradiation device 308 through the transparent substrate film 105 in a state where the layer formed from the resin liquid on the transparent substrate film 105 is in close contact with the mirror surface metal roll or the embossing metal roll 305. By doing so, the layer formed from the resin liquid is cured to form the light diffusion layer 106. Since the irradiated surface becomes high temperature due to ultraviolet irradiation, the mirror surface metal roll or the embossing metal roll 305 preferably includes a cooling device for adjusting the surface temperature to about room temperature to 80 ° C. . Further, one or a plurality of ultraviolet irradiation devices 308 can be used. The transparent substrate film 105 (light diffusion film 102) on which the light diffusion layer 106 is formed is peeled off from the mirror surface metal roll or the embossing metal roll 305 by the peeling roll 307. The light diffusion film 102 manufactured as described above is wound up by the winding device 309. At this time, for the purpose of protecting the light diffusion layer 106, light is applied to the surface of the light diffusion layer 106 while attaching a surface protective film formed of polyethylene terephthalate, polyethylene or the like through a pressure-sensitive adhesive layer having removability. The diffusion film 102 may be wound up.
　なお、剥離ロール３０７によって鏡面金属製ロールまたはエンボス加工用金属製ロール３０５から剥離された後に、追加の紫外線照射を行なってもよい。また、鏡面金属製ロールまたはエンボス加工用金属製ロール３０５と樹脂液から形成された層とが密着した状態で紫外線照射を行なう代わりに、未硬化の樹脂液から形成された層が形成された透明基材フィルム１０５を鏡面金属製ロールまたはエンボス加工用金属製ロール３０５から剥離した後に、紫外線を照射して樹脂液から形成された層を硬化させてもよい。 In addition, after peeling from the mirror surface metal roll or the embossing metal roll 305 by the peeling roll 307, additional ultraviolet irradiation may be performed. Moreover, instead of performing ultraviolet irradiation in a state where the mirror metal roll or the embossing metal roll 305 and the layer formed from the resin liquid are in close contact with each other, a transparent layer formed from an uncured resin liquid is formed. After peeling the base film 105 from the mirror surface metal roll or the embossing metal roll 305, the layer formed from the resin liquid may be cured by irradiating ultraviolet rays.
　光拡散フィルム１０２と偏光フィルム１０１とは、接着剤層などを介して互いに貼合される。光拡散フィルム１０２は、偏光フィルム１０１の保護フィルムとしても機能しており、このような構成は、光拡散性偏光板１００の薄膜化に有利である。光拡散フィルム１０２と偏光フィルム１０１との接着剤を用いた貼合は、表面処理フィルム１０３と光拡散フィルム１０２との貼合について後述するものと同様の接着剤を用いて同様の方法によって行なうことができる。 The light diffusion film 102 and the polarizing film 101 are bonded to each other through an adhesive layer or the like. The light diffusing film 102 also functions as a protective film for the polarizing film 101, and such a configuration is advantageous for reducing the thickness of the light diffusing polarizing plate 100. The bonding using the adhesive between the light diffusion film 102 and the polarizing film 101 is performed by the same method using the same adhesive as described later for the bonding between the surface treatment film 103 and the light diffusion film 102. Can do.
　（表面処理フィルム）
　表面処理フィルム１０３は、透明樹脂フィルム１０７の一方の面に光学的処理が施されたフィルムであり、具体的には、透明樹脂フィルム１０７の一方の面に所望の光学機能を有する表面処理層１０８を形成したフィルムであることができる。透明樹脂フィルム１０７としては、たとえば、ＴＡＣ（トリアセチルセルロース）等のセルロースアセテート系樹脂；ポリメタクリル酸メチル等のアクリル系樹脂；ポリカーボネート樹脂；およびポリエチレンテレフタレート等のポリエステル系樹脂；などから構成される樹脂フィルムを用いることができる。透明樹脂フィルム１０７の厚さは、たとえば１０～５００μｍであり、好ましくは２０～３００μｍである。 (Surface treatment film)
The surface treatment film 103 is a film in which one surface of the transparent resin film 107 is optically treated. Specifically, the surface treatment layer 108 having a desired optical function on one surface of the transparent resin film 107. It can be a film formed. As the transparent resin film 107, for example, a cellulose acetate resin such as TAC (triacetyl cellulose); an acrylic resin such as polymethyl methacrylate; a polycarbonate resin; and a polyester resin such as polyethylene terephthalate; A film can be used. The thickness of the transparent resin film 107 is, for example, 10 to 500 μm, and preferably 20 to 300 μm.
　表面処理フィルム１０３としては、たとえば、表面処理層１０８が表面に凹凸を有する防眩層であり、表面での前記凹凸による乱反射を利用して表示画面への外光の映り込みを低減または防止する（すなわち、上記光学的処理が防眩処理である）防眩フィルムや、表面処理層１０８が反射防止層であり、表示画面に入射した外光の反射を低減または防止することにより、表示画面への外光の映り込みを低減または防止する（すなわち、上記光学的処理が反射防止処理である）反射防止フィルムを挙げることができる。 As the surface treatment film 103, for example, the surface treatment layer 108 is an anti-glare layer having irregularities on the surface, and reduces or prevents reflection of external light on the display screen by using irregular reflection due to the irregularities on the surface. The antiglare film (that is, the optical treatment is an antiglare treatment) or the surface treatment layer 108 is an antireflection layer, which reduces or prevents the reflection of external light incident on the display screen to the display screen. An antireflection film that reduces or prevents reflection of external light (that is, the optical treatment is an antireflection treatment) can be used.
　防眩フィルムとしては、たとえば、透明樹脂フィルム１０７上に微粒子を含有するまたは含有しない紫外線硬化型樹脂組成物を塗工し、形成された紫外線硬化型樹脂層に所定の表面凹凸形状を有する金型の該凹凸面を押し付けながら紫外線硬化型樹脂層を硬化させることにより形成した、所定の表面凹凸が付与された防眩層を有するものや、透明樹脂フィルム１０７上に微粒子を含有する紫外線硬化型樹脂組成物を塗工し、金型を用いることなく、塗工した紫外線硬化型樹脂層を硬化させることにより形成した、微粒子による所定の表面凹凸が付与された防眩層を有するものなどを用いることができる。防眩フィルムとして、市販の防眩フィルムを使用することもできる。 As the antiglare film, for example, a mold having a predetermined surface irregularity on the ultraviolet curable resin layer formed by coating an ultraviolet curable resin composition containing or not containing fine particles on the transparent resin film 107. And an ultraviolet curable resin containing fine particles on the transparent resin film 107 formed by curing the ultraviolet curable resin layer while pressing the concavo-convex surface of the transparent resin film 107. Applying the composition and using an anti-glare layer provided with predetermined surface irregularities by fine particles formed by curing the applied UV-curable resin layer without using a mold Can do. A commercially available anti-glare film can also be used as the anti-glare film.
　反射防止フィルムとしては、たとえば、光拡散層１０６の屈折率よりも低い屈折率を有する材料から構成された低屈折率層を反射防止層として備えるものや、光拡散層１０６の屈折率より高い屈折率を有する材料から構成された高屈折率層と、この高屈折率層の屈折率より低い屈折率を有する材料から構成された低屈折率層との積層を反射防止層として備えるものなどを挙げることができる。低屈折率層は、たとえば、シリカ；金属フッ化物微粒子（ＬｉＦ、ＭｇＦ、３ＮａＦ・ＡｌＦ、ＡｌＦ、Ｎａ3ＡｌＦ6等）；内部に空隙を有する微粒子（中空シリカ微粒子等）；フッ素含有ポリマー；などの低屈折率材料、およびバインダー樹脂を含有するものであることができる。バインダー樹脂は従来公知のものであってよく、ポリシロキサン樹脂、ケイ素アルコキシドの加水分解物、光または熱硬化性多分岐化合物（デンドリマーやハイパーブランチポリマー等）、その他の光または熱硬化性樹脂であることができる。透明樹脂フィルム１０７と低屈折率層または高屈折率層との間には、ハードコート層や帯電防止層等の他の層の１種または２種以上が介在していてもよい。反射防止フィルムとして、市販の反射防止フィルムを使用することもできる。 As an antireflection film, for example, a film having a low refractive index layer made of a material having a refractive index lower than that of the light diffusion layer 106 as an antireflection layer, or a refractive index higher than the refractive index of the light diffusion layer 106 is used. A layer having a high refractive index layer composed of a material having a refractive index and a low refractive index layer composed of a material having a refractive index lower than that of the high refractive index layer as an antireflection layer be able to. The low refractive index layer is, for example, silica; metal fluoride fine particles (LiF, MgF, 3NaF / AlF, AlF, Na 3 AlF 6 etc.); fine particles having voids inside (hollow silica fine particles etc.); fluorine-containing polymer; And a low refractive index material and a binder resin. The binder resin may be a conventionally known one, and is a polysiloxane resin, a hydrolyzate of silicon alkoxide, a light or thermosetting multi-branched compound (such as a dendrimer or a hyperbranched polymer), or other light or thermosetting resin. be able to. One or more of other layers such as a hard coat layer and an antistatic layer may be interposed between the transparent resin film 107 and the low refractive index layer or the high refractive index layer. A commercially available antireflection film can also be used as the antireflection film.
　（粘着剤層、接着剤層）
　本発明の光拡散性偏光板１００において、表面処理フィルム１０３は、通常、その透明樹脂フィルム１０７の表面処理層１０８に近い側とは反対側の面（表面処理フィルム１０３の光学的処理が施されていない面）で、粘着剤層または接着剤層１０４を介して光拡散フィルム１０２の光拡散層１０６に貼合される。 (Adhesive layer, adhesive layer)
In the light diffusing polarizing plate 100 of the present invention, the surface treatment film 103 is usually a surface opposite to the surface of the transparent resin film 107 close to the surface treatment layer 108 (optical treatment of the surface treatment film 103 is performed). On the light diffusion layer 106 of the light diffusion film 102 via the pressure-sensitive adhesive layer or the adhesive layer 104.
　粘着剤層１０４を形成する粘着剤としては、従来公知のものを用いることができ、たとえば、アクリル系粘着剤、ウレタン系粘着剤、シリコーン系粘着剤などが挙げられる。中でも、透明性、粘着力、信頼性、リワーク性などの観点から、アクリル系粘着剤が好ましく用いられる。粘着剤層１０４は、このような粘着剤を、たとえば有機溶剤溶液とし、それを光拡散層１０６または透明樹脂フィルム１０７上にダイコーターやグラビアコーターなどによって塗布し、乾燥させる方法によって設けることができる他、離型処理が施されたプラスチックフィルム（セパレートフィルムと呼ばれる）上に形成されたシート状粘着剤を光拡散層１０６または透明樹脂フィルム１０７に転写する方法によっても設けることができる。粘着剤層の厚さは、通常２～４０μｍの範囲内である。 As the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer 104, conventionally known ones can be used, and examples thereof include acrylic pressure-sensitive adhesives, urethane pressure-sensitive adhesives, and silicone-based pressure-sensitive adhesives. Among these, an acrylic pressure-sensitive adhesive is preferably used from the viewpoints of transparency, adhesive strength, reliability, reworkability, and the like. The pressure-sensitive adhesive layer 104 can be provided by a method in which such a pressure-sensitive adhesive is, for example, an organic solvent solution, which is applied onto the light diffusion layer 106 or the transparent resin film 107 by a die coater or a gravure coater and dried. In addition, it can be provided by a method of transferring a sheet-like pressure-sensitive adhesive formed on a plastic film (referred to as a separate film) subjected to a release treatment to the light diffusion layer 106 or the transparent resin film 107. The thickness of the pressure-sensitive adhesive layer is usually in the range of 2 to 40 μm.
　また、接着剤層１０４を形成する接着剤としては、光拡散性偏光板１００の外観に悪影響を及ぼすことなく、表面処理フィルム１０３と光拡散フィルム１０２とを高い接着強度で接着できることから、エポキシ樹脂を含有する硬化性樹脂組成物等の活性エネルギー線または熱硬化性樹脂組成物を含む接着剤や、接着剤成分としてポリビニルアルコール系樹脂またはウレタン樹脂を含有する水系接着剤などを好ましく用いることができる。中でも、乾燥工程を要しない等の生産効率の向上を図ることができ、良好な接着強度が得られることから、エポキシ樹脂を含有する硬化性樹脂組成物を含む接着剤がより好ましく用いられる。 Further, as an adhesive for forming the adhesive layer 104, an epoxy resin can be used because the surface treatment film 103 and the light diffusion film 102 can be bonded with high adhesive strength without adversely affecting the appearance of the light diffusing polarizing plate 100. An adhesive containing an active energy ray or a thermosetting resin composition such as a curable resin composition containing water, or an aqueous adhesive containing a polyvinyl alcohol resin or a urethane resin as an adhesive component can be preferably used. . Especially, since the improvement of production efficiency, such as not requiring a drying process, can be aimed at and favorable adhesive strength is obtained, the adhesive agent containing the curable resin composition containing an epoxy resin is used more preferable.
　エポキシ樹脂を含有する硬化性樹脂組成物を含む接着剤を用いた表面処理フィルム１０３と光拡散フィルム１０２との貼合は、該接着剤を光拡散層１０６または透明樹脂フィルム１０７上に塗工し、未硬化の接着剤層を介して両フィルムを積層した後、活性エネルギー線を照射するか、または加熱することにより、未硬化の接着剤層を硬化させることにより行なうことができる。接着剤の塗工方法に特別な限定はなく、たとえば、ドクターブレード、ワイヤーバー、ダイコーター、コンマコーター、グラビアコーターなど、種々の塗工方式が利用できる。各塗工方式には各々最適な粘度範囲があるため、有機溶剤を用いて接着剤の粘度調整を行なってもよい。硬化後の接着剤層の厚さは、通常０．１～２０μｍであり、好ましくは０．２～１０μｍ、さらに好ましくは０．５～５μｍである。 Bonding of the surface treatment film 103 and the light diffusion film 102 using an adhesive containing a curable resin composition containing an epoxy resin is performed by applying the adhesive on the light diffusion layer 106 or the transparent resin film 107. Then, after laminating both films via an uncured adhesive layer, the film can be cured by irradiating with active energy rays or heating to cure the uncured adhesive layer. There are no particular limitations on the method of applying the adhesive, and various coating methods such as a doctor blade, a wire bar, a die coater, a comma coater, and a gravure coater can be used. Since each coating method has an optimum viscosity range, the viscosity of the adhesive may be adjusted using an organic solvent. The thickness of the adhesive layer after curing is usually 0.1 to 20 μm, preferably 0.2 to 10 μm, more preferably 0.5 to 5 μm.
　透明樹脂フィルム１０７および／または光拡散層１０６の貼合面には、粘着剤または接着剤による貼合に先立って、コロナ放電処理、プライマー処理（プライマー層の形成）などの易接着処理が施されてもよい。 Prior to the bonding with the adhesive or the adhesive, the bonding surface of the transparent resin film 107 and / or the light diffusion layer 106 is subjected to an easy adhesion process such as a corona discharge process or a primer process (formation of a primer layer). May be.
　（保護フィルム）
　図１に示されるように、本発明の光拡散性偏光板は、偏光フィルム１０１の光拡散フィルム１０２とは反対側に接着剤層等を介して積層された保護フィルム１０９を備えていてもよい。保護フィルム１０９は、低複屈折性で、透明性や機械的強度、熱安定性や水分遮蔽性などに優れるポリマーから構成されるフィルムであることが好ましい。このようなフィルムとしては、たとえば、ＴＡＣ（トリアセチルセルロース）などのセルロースアセテート系樹脂；アクリル系樹脂；四フッ化エチレン／六フッ化プロピレン系共重合体のようなフッ素系樹脂；ポリカーボネート樹脂；ポリエチレンテレフタレート等のポリエステル系樹脂；ポリイミド系樹脂；ポリスルホン系樹脂；ポリエーテルスルホン系樹脂；ポリスチレン系樹脂；ポリビニルアルコール系樹脂；ポリ塩化ビニル系樹脂；ポリオレフィン系樹脂もしくはポリアミド系樹脂等から構成される樹脂フィルムが挙げられる。これらの中でも、偏光特性や耐久性などの点から、トリアセチルセルロースフィルムや、ノルボルネン系熱可塑性樹脂フィルムが好ましく使用できる。ノルボルネン系熱可塑性樹脂フィルムは、耐湿熱性が高いため、偏光板の耐久性を大幅に向上させることができるとともに、吸湿性が少ないため、寸法安定性が高く、特に好適である。上記樹脂のフィルムへの成形加工は、キャスティング法、カレンダー法、押出法等の従来公知の方法を用いることができる、保護フィルム１０９の厚さに限定はないが、偏光板の薄膜化等の観点から５００μｍ以下が好ましく、より好ましくは５～３００μｍの範囲、さらに好ましくは５～１５０μｍの範囲である。 (Protective film)
As shown in FIG. 1, the light diffusing polarizing plate of the present invention may include a protective film 109 laminated on the opposite side of the polarizing film 101 from the light diffusing film 102 via an adhesive layer or the like. . The protective film 109 is preferably a film made of a polymer that has low birefringence and is excellent in transparency, mechanical strength, thermal stability, moisture shielding properties, and the like. Examples of such films include cellulose acetate resins such as TAC (triacetyl cellulose); acrylic resins; fluorine resins such as tetrafluoroethylene / hexafluoropropylene copolymers; polycarbonate resins; polyethylenes Polyester resin such as terephthalate; Polyimide resin; Polysulfone resin; Polyethersulfone resin; Polystyrene sulfone resin; Polyvinyl alcohol resin; Polyvinyl chloride resin; Resin film composed of polyolefin resin or polyamide resin Is mentioned. Among these, a triacetyl cellulose film and a norbornene-based thermoplastic resin film can be preferably used from the viewpoints of polarization characteristics and durability. The norbornene-based thermoplastic resin film is particularly suitable because it has high moisture and heat resistance and can greatly improve the durability of the polarizing plate and has high dimensional stability because of low hygroscopicity. For forming the resin into a film, a conventionally known method such as a casting method, a calendar method, and an extrusion method can be used. The thickness of the protective film 109 is not limited. To 500 μm or less, more preferably in the range of 5 to 300 μm, still more preferably in the range of 5 to 150 μm.
　偏光フィルム１０１と保護フィルム１０９との接着剤を用いた貼合は、表面処理フィルム１０３と光拡散フィルム１０２との貼合について上述したものと同様の接着剤を用いて同様の方法によって行なうことができる。 The bonding using the adhesive between the polarizing film 101 and the protective film 109 can be performed by the same method using the same adhesive as described above for the bonding between the surface treatment film 103 and the light diffusion film 102. it can.
　なお、偏光フィルム１０１には、保護フィルム１０９の代わりに、位相差フィルム（位相差板）等の光学補償フィルムなどが貼合されてもよい。 Note that an optical compensation film such as a retardation film (retardation plate) may be bonded to the polarizing film 101 instead of the protective film 109.
　以上のような構成の光拡散性偏光板１００は、典型的には、液晶表示装置に適用する場合、表面処理フィルム１０３が偏光フィルム１０１よりも視認側となるように、粘着剤層等を介して液晶セルのガラス基板に貼着されて液晶表示装置に組み込まれる。 Typically, when the light diffusing polarizing plate 100 having the above-described configuration is applied to a liquid crystal display device, an adhesive layer or the like is interposed so that the surface treatment film 103 is closer to the viewing side than the polarizing film 101. Then, it is attached to the glass substrate of the liquid crystal cell and incorporated into the liquid crystal display device.
　＜液晶表示装置＞
　次に、本発明に係る液晶表示装置について説明する。本発明の液晶表示装置は、バックライト装置と、光拡散手段と、バックライト側偏光板と、液晶セルと、上記本発明の光拡散性偏光板とをこの順で備えるものである。図３は、本発明の液晶表示装置の好ましい一例を示す概略断面図である。図３の液晶表示装置４００は、ノーマリーホワイトモードのＴＮ方式の液晶表示装置であって、バックライト装置４０２、光拡散手段４０３、バックライト側偏光板４０４、および、視認側偏光板である本発明に係る光拡散性偏光板４０５がこの順で配置されてなり、液晶セル４０１は、液晶層４１２と、液晶層４１２の両面に配置された一対の透明基板４１１ａ、４１１ｂとから構成される。バックライト側偏光板４０４と光拡散性偏光板４０５は、それらの透過軸が直交ニコルの関係となるように配置される。 <Liquid crystal display device>
Next, the liquid crystal display device according to the present invention will be described. The liquid crystal display device of the present invention comprises a backlight device, a light diffusion means, a backlight side polarizing plate, a liquid crystal cell, and the light diffusing polarizing plate of the present invention in this order. FIG. 3 is a schematic sectional view showing a preferred example of the liquid crystal display device of the present invention. The liquid crystal display device 400 of FIG. 3 is a normally white mode TN liquid crystal display device, which is a backlight device 402, a light diffusion means 403, a backlight side polarizing plate 404, and a viewing side polarizing plate. The light diffusing polarizing plate 405 according to the invention is arranged in this order, and the liquid crystal cell 401 includes a liquid crystal layer 412 and a pair of transparent substrates 411 a and 411 b arranged on both surfaces of the liquid crystal layer 412. The backlight side polarizing plate 404 and the light diffusing polarizing plate 405 are disposed so that their transmission axes have a crossed Nicols relationship.
　バックライト装置４０２は、前面開口の六面体形状のケース４２１と、ケース４２１内に複数本並列配置された、線状光源としての冷陰極管４２２とを備える直下型のバックライト装置である。また、光拡散手段４０３は、バックライト装置４０２の前面に配置された光拡散板４０３ａと、光拡散板４０３ａの前面側（光拡散板４０３ａとバックライト側偏光板４０４との間）に設けられた光偏向板（プリズムシート）４０３ｂとから構成される。 The backlight device 402 is a direct-type backlight device including a hexahedron-shaped case 421 having a front opening and a plurality of cold cathode tubes 422 as linear light sources arranged in parallel in the case 421. The light diffusing unit 403 is provided on the front surface of the backlight device 402, and on the front side of the light diffusing plate 403a (between the light diffusing plate 403a and the backlight side polarizing plate 404). And an optical deflection plate (prism sheet) 403b.
　このような構成の液晶表示装置４００において、バックライト装置４０２から放射された光は、光拡散手段４０３の光拡散板４０３ａによって拡散された後、光偏向板４０３ｂによって液晶セル４０１の光入射面の垂線方向（ｚ軸方向）への所定の指向性が付与される。この垂線方向への指向性は従来の装置よりも高い設定とされている。そして、所定の指向性が付与された光は、バックライト側偏光板４０４によって偏光とされて液晶セル４０１に入射する。液晶セル４０１に入射した光は、液晶層４１２によって偏光状態が制御されて液晶セル４０１から出射する。そして、液晶セル４０１から出射した光は、光拡散性偏光板４０５によって拡散される。 In the liquid crystal display device 400 having such a configuration, the light emitted from the backlight device 402 is diffused by the light diffusing plate 403a of the light diffusing means 403, and then the light incident surface of the liquid crystal cell 401 by the light deflecting plate 403b. Predetermined directivity in the perpendicular direction (z-axis direction) is given. The directivity in the perpendicular direction is set to be higher than that of the conventional device. The light having a predetermined directivity is polarized by the backlight side polarizing plate 404 and enters the liquid crystal cell 401. The light incident on the liquid crystal cell 401 is emitted from the liquid crystal cell 401 with the polarization state controlled by the liquid crystal layer 412. The light emitted from the liquid crystal cell 401 is diffused by the light diffusing polarizing plate 405.
　このように、本発明の液晶表示装置では、光拡散手段４０３における、液晶セル４０１に入射する光の、液晶セル４０１の光入射面の垂線方向（ｚ軸方向）への指向性を従来よりも高くする、すなわち液晶セル４０１への入射光を従来よりも集光されたものとし、これを光拡散性偏光板４０５によってさらに拡散させる。これによって、従来の装置に比べて色再現性などの優れた画像品位が得られるようになる。本発明の光拡散性偏光板４０５を適用した本発明の液晶表示装置４００は、高い視野角特性を有するとともに、光拡散性偏光板４０５に付与された光拡散機能以外の光学機能を兼備しており、視認性に優れる。 Thus, in the liquid crystal display device of the present invention, the directivity of the light incident on the liquid crystal cell 401 in the light diffusing unit 403 in the perpendicular direction (z-axis direction) of the light incident surface of the liquid crystal cell 401 is higher than before. That is, the incident light to the liquid crystal cell 401 is collected more than before, and this is further diffused by the light diffusing polarizing plate 405. This makes it possible to obtain an excellent image quality such as color reproducibility as compared with the conventional apparatus. The liquid crystal display device 400 of the present invention to which the light diffusing polarizing plate 405 of the present invention is applied has high viewing angle characteristics and also has an optical function other than the light diffusing function provided to the light diffusing polarizing plate 405. Excellent visibility.
　以下、本発明の液晶表示装置４００を構成する構成部材についてより詳細に説明する。 Hereinafter, the constituent members constituting the liquid crystal display device 400 of the present invention will be described in more detail.
　（液晶セル）
　液晶セル４０１は一対の透明基板４１１ａ、４１１ｂと液晶層４１２とを備え、一対の透明基板４１１ａ、４１１ｂはスペーサーにより所定距離を隔てて対向配置されており、液晶層４１２は一対の透明基板４１１ａ、４１１ｂの間に封入された液晶から構成される。一対の透明基板４１１ａ、４１１ｂには、それぞれ透明電極や配向膜が積層形成されており、透明電極間に表示データに基づいた電圧が印加されることによって液晶が配向する。液晶セル４０１の表示方式は、上記の例ではＴＮ方式であるが、ＩＰＳ方式、ＶＡ方式などの表示方式も採用してもよい。 (Liquid crystal cell)
The liquid crystal cell 401 includes a pair of transparent substrates 411a and 411b and a liquid crystal layer 412. The pair of transparent substrates 411a and 411b are arranged to face each other with a predetermined distance by a spacer, and the liquid crystal layer 412 includes a pair of transparent substrates 411a and 411a. It is composed of liquid crystal sealed between 411b. The pair of transparent substrates 411a and 411b are each formed by laminating a transparent electrode and an alignment film, and the liquid crystal is aligned by applying a voltage based on display data between the transparent electrodes. The display method of the liquid crystal cell 401 is the TN method in the above example, but a display method such as an IPS method or a VA method may also be adopted.
　（バックライト装置）
　バックライト装置４０２は、前面開口の六面体形状のケース４２１と、ケース４２１内に複数本並列配置された、線状光源としての冷陰極管４２２とを備える。ケース４２１は、樹脂材料や金属材料から成形され、冷陰極管４２２から放射された光をケース４２１内周面で反射させる観点から、少なくともケース４２１内周面は白色または銀色であることが望ましい。光源としては、冷陰極管の他、線状形状等の各種形状のＬＥＤ等も使用できる。線状光源を用いる場合、配置する線状光源の本数に特に限定はないが、発光面の輝度ムラの抑制等の観点から、隣接する線状光源の中心間距離が１５ｍｍから１５０ｍｍの範囲であることが好ましい。なお、本発明で使用するバックライト装置４０２は、図３に示す直下型のものに限定されるものではなく、導光板の側面に線状光源または点状光源を配置したサイドライト型、あるいは平面状光源型などの各種のものが使用できる。 (Backlight device)
The backlight device 402 includes a hexahedron-shaped case 421 having a front opening, and a plurality of cold cathode tubes 422 as linear light sources arranged in parallel in the case 421. The case 421 is molded from a resin material or a metal material, and at least the inner peripheral surface of the case 421 is desirably white or silver from the viewpoint of reflecting the light emitted from the cold cathode fluorescent lamp 422 on the inner peripheral surface of the case 421. As a light source, LEDs of various shapes such as a linear shape can be used in addition to a cold cathode tube. When the linear light source is used, the number of the linear light sources to be arranged is not particularly limited, but the distance between the centers of the adjacent linear light sources is in the range of 15 mm to 150 mm from the viewpoint of suppressing luminance unevenness on the light emitting surface. It is preferable. Note that the backlight device 402 used in the present invention is not limited to the direct type shown in FIG. 3, but is a sidelight type in which a linear light source or a point light source is arranged on the side surface of the light guide plate, or a flat type. Various types such as a shape light source type can be used.
　〔光拡散手段〕
　光拡散手段４０３は、図４に示されるように、バックライト装置４０２の前面に配置された光拡散板４０３ａと、光拡散板４０３ａの前面側（光拡散板４０３ａとバックライト側偏光板４０４との間）に設けられた光偏向板（プリズムシート）４０３ｂとから構成されることが好ましい。光拡散板４０３ａは、たとえば、図４に示されるように、基材４３０に光拡散剤４４０が分散混合されてなるフィルムまたはシートであることができる。基材４３０としては、ポリカーボネート系樹脂；メタクリル系樹脂；メタクリル酸メチル－スチレン共重合体樹脂；アクリロニトリル－スチレン共重合体樹脂；メタクリル酸－スチレン共重合体樹脂；ポリスチレン系樹脂；ポリ塩化ビニル系樹脂；ポリプロピレンやポリメチルペンテン等のポリオレフィン系樹脂；環状ポリオレフィン系樹脂；ポリエチレンテレフタレートやポリブチレンテレフタレート、ポリエチレンナフタレート等のポリエステル系樹脂；ポリアミド系樹脂；ポリアリレート系樹脂；ポリイミド系樹脂；等が使用できる。 [Light diffusion means]
As shown in FIG. 4, the light diffusing unit 403 includes a light diffusing plate 403a disposed on the front surface of the backlight device 402, and a front surface side of the light diffusing plate 403a (light diffusing plate 403a and backlight side polarizing plate 404). And a light deflection plate (prism sheet) 403b provided between the two. For example, as shown in FIG. 4, the light diffusing plate 403 a can be a film or sheet in which a light diffusing agent 440 is dispersed and mixed with a base material 430. As the base material 430, polycarbonate resin; methacrylic resin; methyl methacrylate-styrene copolymer resin; acrylonitrile-styrene copolymer resin; methacrylic acid-styrene copolymer resin; polystyrene resin; Polyolefin resins such as polypropylene and polymethylpentene; cyclic polyolefin resins; polyester resins such as polyethylene terephthalate, polybutylene terephthalate and polyethylene naphthalate; polyamide resins; polyarylate resins; polyimide resins; .
　また、基材４３０に混合分散させる光拡散剤４４０は、基材４３０の材料とは屈折率が異なる材料から形成される微粒子である限り特に制限されないが、たとえば、基材４３０の材料とは異なる種類のアクリル系樹脂、メラミン樹脂、ポリエチレン樹脂、ポリスチレン樹脂、有機シリコーン樹脂、アクリル－スチレン共重合体樹脂などから形成される有機微粒子、および炭酸カルシウム、シリカ、酸化アルミニウム、炭酸バリウム、硫酸バリウム、酸化チタン、ガラスなどから形成される無機微粒子が挙げられる。使用する光拡散剤４４０は、１種のみであってもよく、２種以上を併用してもよい。また、有機重合体のバルーンやガラス中空ビーズも光拡散剤４４０として使用できる。光拡散剤４４０の重量平均粒径は０．５～３０μｍの範囲が好ましい。また、光拡散剤４４０の形状は球形、偏平、板状、針状等であってよいが、好ましくは球形である。 The light diffusing agent 440 mixed and dispersed in the base material 430 is not particularly limited as long as it is a fine particle formed of a material having a refractive index different from that of the base material 430. For example, it is different from the material of the base material 430. Organic fine particles formed from various types of acrylic resin, melamine resin, polyethylene resin, polystyrene resin, organic silicone resin, acrylic-styrene copolymer resin, and calcium carbonate, silica, aluminum oxide, barium carbonate, barium sulfate, oxidation Inorganic fine particles formed from titanium, glass and the like can be mentioned. Only one type of light diffusing agent 440 may be used, or two or more types may be used in combination. An organic polymer balloon or glass hollow beads can also be used as the light diffusing agent 440. The weight average particle diameter of the light diffusing agent 440 is preferably in the range of 0.5 to 30 μm. The light diffusing agent 440 may have a spherical shape, a flat shape, a plate shape, a needle shape, or the like, but is preferably a spherical shape.
　一方、光偏向板（プリズムシート）４０３ｂは、光入射面側（バックライト装置４０２側、図４に示すｚ軸の負方向側）の面が平坦面で、光出射側（図４に示すｚ軸の正方向側）の面（バックライト側偏光板４０４に対向する表面）に、断面が先細の多角形状、好ましくは三角形状の線状プリズム４５０が平行に複数形成されたものである。光偏向板４０３ｂの材料としては、たとえば、ポリカーボネート系樹脂；ＡＢＳ樹脂；メタクリル樹脂；メタクリル酸メチル－スチレン共重合体樹脂；ポリスチレン系樹脂；アクリロニトリル－スチレン共重合体樹脂；ポリエチレンやポリプロピレン等のポリオレフィン系樹脂；等が挙げられる。光偏向板４０３ｂの作製方法としては、通常の熱可塑性樹脂の成形法を用いることができ、たとえば、金型を用いた熱プレス成形や、押出成形などが挙げられる。光偏向板４０３ｂの厚さは、通常、０．１～１５ｍｍであり、好ましくは０．５～１０ｍｍである。なお、本明細書において、「光偏向板の厚さ」とは、光偏向板４０３ｂの光拡散板４０３ａに近い側の面から線状プリズム４５０の頂角の先端までの最大厚さのことを指す。したがって、図４に示すＢに相当する最も厚い部分が光偏向板４０３ｂの厚さとなる。光偏向板４０３ｂの光拡散板４０３ａに近い側の面から線状プリズム４５０の頂角の先端までの厚みが最大でない部分（例えば、線状プリズム４５０の谷の部分）においては、光偏向板４０３ｂの厚さは上記範囲でなくてもよい。 On the other hand, the light deflection plate (prism sheet) 403b has a flat surface on the light incident surface side (the backlight device 402 side, the negative direction side of the z axis shown in FIG. 4) and the light emitting side (z shown in FIG. 4). A plurality of linear prisms 450 having a tapered cross section, preferably a triangular shape, are formed in parallel on the surface on the positive side of the axis (the surface facing the backlight side polarizing plate 404). Examples of the material of the light deflector 403b include polycarbonate resin; ABS resin; methacrylic resin; methyl methacrylate-styrene copolymer resin; polystyrene resin; acrylonitrile-styrene copolymer resin; polyolefins such as polyethylene and polypropylene. Resin; and the like. As a method for producing the light deflection plate 403b, a normal thermoplastic resin molding method can be used, and examples thereof include hot press molding using a mold and extrusion molding. The thickness of the light deflection plate 403b is usually 0.1 to 15 mm, preferably 0.5 to 10 mm. In this specification, the “thickness of the light deflection plate” refers to the maximum thickness from the surface of the light deflection plate 403b close to the light diffusion plate 403a to the apex of the apex angle of the linear prism 450. Point to. Therefore, the thickest portion corresponding to B shown in FIG. 4 is the thickness of the light deflection plate 403b. In a portion where the thickness from the surface of the light deflecting plate 403b close to the light diffusing plate 403a to the tip of the apex angle of the linear prism 450 is not maximum (for example, the valley portion of the linear prism 450), the light deflecting plate 403b. The thickness may not be in the above range.
　光拡散板４０３ａと光偏向板４０３ｂとは一体に成形してもよいし、別々に作製した後接合してもよい。また、別々に作製し接合する場合、光拡散板４０３ａと光偏向板４０３ｂとの間に空気層を介して接触させてもよい。また、光拡散板４０３ａと光偏向板４０３ｂとは、離間して配置してもよい。 The light diffusing plate 403a and the light deflecting plate 403b may be integrally formed, or may be formed separately and then joined. Further, in the case of separately producing and joining, the light diffusing plate 403a and the light deflecting plate 403b may be contacted via an air layer. Further, the light diffusion plate 403a and the light deflection plate 403b may be arranged apart from each other.
　光拡散手段４０３は、図５に示すように、光偏向機能を奏する光偏向板４０３ｂに光拡散剤４４０を分散混合させて、光拡散機能を付与したものであってもよい。 As shown in FIG. 5, the light diffusing unit 403 may be provided with a light diffusing function by dispersing and mixing a light diffusing agent 440 on a light deflecting plate 403 b having a light deflecting function.
　さらに、光拡散手段４０３は、図６に示すように、光拡散板４０３ａの前面側に配置された２枚の光偏向板（プリズムシート）４０３ｂ、４０３ｂ’を有するものであってもよい。この場合、図６を参照して、光拡散板４０３ａに近い側に配置される光偏向板４０３ｂは、その線状プリズム４５０の稜線４５１の方向がバックライト側偏光板４０４の透過軸方向（ｙ軸方向）と実質的に平行となるよう配置され、光偏向板４０３ｂの前面側に配置される光偏向板４０３ｂ’は、その線状プリズム４５０’の稜線４５１’の方向が光拡散性偏光板４０５の透過軸方向（ｘ軸方向）と実質的に平行となるように配置されることが好ましい。このような構成により、液晶表示装置における正面方向の輝度をより向上させることができる。ただし、光偏向板４０３ｂ’の線状プリズム４５０’の稜線４５１’の方向がバックライト側偏光板４０４の透過軸方向（ｙ軸方向）と実質的に平行となるよう配置し、光偏向板４０３ｂの線状プリズム４５０の稜線４５１の方向が光拡散性偏光板４０５の透過軸方向（ｘ軸方向）と実質的に平行となるように配置することも可能である。 Further, as shown in FIG. 6, the light diffusing unit 403 may include two light deflecting plates (prism sheets) 403b and 403b 'disposed on the front side of the light diffusing plate 403a. In this case, referring to FIG. 6, in the light deflection plate 403b disposed on the side closer to the light diffusion plate 403a, the direction of the ridge line 451 of the linear prism 450 is the transmission axis direction (y The light deflection plate 403b ′ disposed substantially parallel to the axial direction) and disposed on the front surface side of the light deflection plate 403b has a direction of the ridge line 451 ′ of the linear prism 450 ′ as a light diffusing polarizing plate. It is preferable to be arranged so as to be substantially parallel to the transmission axis direction 405 (x-axis direction). With such a configuration, the luminance in the front direction of the liquid crystal display device can be further improved. However, the light deflection plate 403b ′ is arranged so that the direction of the ridge line 451 ′ of the linear prism 450 ′ of the light deflection plate 403b ′ is substantially parallel to the transmission axis direction (y-axis direction) of the backlight side polarizing plate 404, and the light deflection plate 403b. The ridge line 451 of the linear prism 450 may be arranged so as to be substantially parallel to the transmission axis direction (x-axis direction) of the light diffusing polarizing plate 405.
　光拡散手段４０３を通過した光の配光特性は、液晶セル４０１の光入射面の垂線方向（図３に示すｚ軸方向）から７０°傾いた方向の輝度値が、正面輝度値、すなわち、液晶セル４０１の光入射面の垂線方向の輝度値に対して２０％以下であり、かつ、光拡散手段４０３からの出射光は非平行光を含むものであることが好ましい。より好ましい配光特性は、液晶セル４０１の光入射面の垂線に対して６０°を超える方向に出射する光がないようにすることである。通常、図３に示すように、光拡散手段４０３の背面（光入射面）と、液晶セル４０１の光入射面とは平行に配置されるので、液晶セル４０１の光入射面の垂線に対して７０°方向の輝度値とは、たとえば、図７に示すように、光拡散手段４０３の長手方向をｘ方向とし、光拡散手段４０３の背面（光入射面）に平行な面をｘｙ面としたときに、このｘｙ面に対する垂線であるｚ軸に対して７０°方向の輝度値となり、好ましくは、ｘｚ面上においてｚ軸となす角が７０°となる方向の輝度値である。このような配光特性とするには、たとえば、光偏向板４０３ｂの断面三角形状の線状プリズム４５０（および／または線状プリズム４５０’）の形状を調整すればよい。線状プリズム４５０，４５０’の頂角θ（図４および図５参照）は、６０～１２０°の範囲が好ましく、より好ましくは９０～１１０°である。この三角形の形状は、等辺、不等辺は任意であるが、液晶セル４０１の垂線方向（液晶表示装置の正面方向、すなわち、ｚ軸方向）に集光しようとする場合には二等辺三角形が好ましい。また、線状プリズムから構成されるプリズム面は、三角形の頂角に相対した底辺が互いに隣接するように順次配置され、複数の線状プリズムが互いにほぼ平行になるように配列した構造とするのが好ましい。この場合、集光能力が著しく減退しない限り、線状プリズムの頂点および隣接する線状プリズムによって形成されるＶ字状溝は、曲線形状となっていてもよい。線状プリズムの稜線間の距離（図４および図５に示される距離ｄ）は、通常、１０μｍ～５００μｍの範囲であり、好ましくは、３０μｍ～２００μｍの範囲である。 The light distribution characteristic of the light that has passed through the light diffusing means 403 is such that the luminance value in the direction inclined by 70 ° from the perpendicular direction (z-axis direction shown in FIG. 3) of the light incident surface of the liquid crystal cell 401 is the front luminance value. It is preferable that it is 20% or less with respect to the luminance value in the perpendicular direction of the light incident surface of the liquid crystal cell 401, and the light emitted from the light diffusing means 403 includes non-parallel light. A more preferable light distribution characteristic is that no light is emitted in a direction exceeding 60 ° with respect to the normal of the light incident surface of the liquid crystal cell 401. Normally, as shown in FIG. 3, the back surface (light incident surface) of the light diffusing means 403 and the light incident surface of the liquid crystal cell 401 are arranged in parallel, so that the perpendicular to the light incident surface of the liquid crystal cell 401 is The luminance value in the 70 ° direction is, for example, as shown in FIG. 7, where the longitudinal direction of the light diffusing unit 403 is the x direction and the plane parallel to the back surface (light incident surface) of the light diffusing unit 403 is the xy plane. Sometimes, the luminance value is in the direction of 70 ° with respect to the z axis, which is a perpendicular to the xy plane, and preferably the luminance value in the direction in which the angle formed with the z axis on the xz plane is 70 °. In order to achieve such a light distribution characteristic, for example, the shape of the linear prism 450 (and / or the linear prism 450 ') having a triangular cross section of the light deflection plate 403b may be adjusted. The apex angle θ (see FIGS. 4 and 5) of the linear prisms 450 and 450 ′ is preferably in the range of 60 to 120 °, more preferably 90 to 110 °. As for the shape of the triangle, an equal side and an unequal side can be arbitrarily selected, but an isosceles triangle is preferable in the case where light is focused in the perpendicular direction of the liquid crystal cell 401 (the front direction of the liquid crystal display device, that is, the z-axis direction). . Also, the prism surface composed of linear prisms is arranged sequentially so that the bases corresponding to the apex angles of the triangles are adjacent to each other, and a plurality of linear prisms are arranged so as to be substantially parallel to each other. Is preferred. In this case, the V-shaped grooves formed by the apexes of the linear prisms and the adjacent linear prisms may be curved as long as the light collecting ability is not significantly reduced. The distance between the ridgelines of the linear prism (distance d shown in FIGS. 4 and 5) is usually in the range of 10 μm to 500 μm, and preferably in the range of 30 μm to 200 μm.
　非平行光とは、図８に示すように、光拡散手段４０３の出射面における直径１ｃｍの円内から出射された光を、該出射面の垂線方向に１ｍ離れた、該出射面に平行な観察面における投影像として観察したとき、その投影像の面内輝度分布の最小半値幅が３０ｃｍ以上であるような出射特性を有する光である。 As shown in FIG. 8, non-parallel light means that light emitted from a circle having a diameter of 1 cm on the exit surface of the light diffusing means 403 is parallel to the exit surface, which is 1 m away from the exit surface in the perpendicular direction. When observed as a projection image on the observation surface, the light has emission characteristics such that the minimum half-value width of the in-plane luminance distribution of the projection image is 30 cm or more.
　（バックライト側偏光板）
　バックライト側偏光板４０４としては、通常は、偏光フィルムの片面または両面に保護フィルムを貼合したものを使用することができる。偏光フィルムおよび保護フィルムとしては、光拡散性偏光板１００について上述したものを用いることができる。 (Backlight side polarizing plate)
As the backlight-side polarizing plate 404, a polarizing film in which a protective film is bonded to one side or both sides can be usually used. As a polarizing film and a protective film, what was mentioned above about the light diffusable polarizing plate 100 can be used.
　（位相差板）
　本発明の液晶表示装置は、図９に示されるように、位相差板４０６を備えることができる。図９に示される液晶表示装置４００’において位相差板４０６は、バックライト側偏光板４０４と液晶セル４０１との間に配置されている。この位相差板４０６は、液晶セル４０１の表面に対して垂直な方向（ｚ軸方向）の位相差がほぼゼロのものであり、真正面からは何ら光学的な作用を及ぼさず、斜めから見たときに位相差を発現し、液晶セル４０１で生じる位相差を補償するものである。これによって、より広い視野角において、より優れた表示品位および色再現性が得られるようになる。位相差板４０６は、バックライト側偏光板４０４と液晶セル４０１との間、および、光拡散性偏光板４０５と液晶セル４０１との間の一方または両方に配置することができる。位相差板４０６は、バックライト側偏光板４０４の保護フィルム上に積層することもできるし、あるいは保護フィルムの機能を兼ねて、バックライト側偏光板４０４の偏光フィルム上に直接積層することもできる。光拡散性偏光板４０５と液晶セル４０１との間に位相差板を配置する場合についても同様である。 (Phase difference plate)
As shown in FIG. 9, the liquid crystal display device of the present invention can include a retardation plate 406. In the liquid crystal display device 400 ′ shown in FIG. 9, the retardation film 406 is disposed between the backlight side polarizing plate 404 and the liquid crystal cell 401. This phase difference plate 406 has a phase difference of almost zero in the direction perpendicular to the surface of the liquid crystal cell 401 (z-axis direction), has no optical effect from the front, and is viewed from an oblique direction. A phase difference is sometimes developed, and the phase difference generated in the liquid crystal cell 401 is compensated. This makes it possible to obtain better display quality and color reproducibility over a wider viewing angle. The retardation plate 406 can be disposed between the backlight side polarizing plate 404 and the liquid crystal cell 401 and between one or both of the light diffusing polarizing plate 405 and the liquid crystal cell 401. The retardation film 406 can be laminated on the protective film of the backlight side polarizing plate 404, or can also be laminated directly on the polarizing film of the backlight side polarizing plate 404 while also serving as a protective film. . The same applies to the case where a retardation plate is disposed between the light diffusing polarizing plate 405 and the liquid crystal cell 401.
　位相差板４０６としては、たとえば、ポリカーボネート樹脂や環状オレフィン系重合体樹脂をフィルムにし、このフィルムをさらに二軸延伸したものや、液晶性モノマーをフィルムに塗布し、光重合反応によってその分子配列を固定化したもの等が挙げられる。位相差板４０６は、液晶の配列を光学的に補償するものであるから、液晶配列と逆の屈折率特性のものを用いる。具体的にはＴＮモードの液晶セルには、たとえば、「ＷＶフィルム」（富士フイルム株式会社製）、ＳＴＮモードの液晶表示セルには、たとえば、「ＬＣフィルム」（新日本石油株式会社製）、ＩＰＳモードの液晶表示セルには、たとえば、二軸性位相差フィルム、ＶＡモードの液晶表示セルには、たとえば、ＡプレートおよびＣプレートを組み合わせた位相差板や二軸性位相差フィルム、πセルモードの液晶表示セルには、たとえば、「ＯＣＢ用ＷＶフィルム」（富士フイルム株式会社製）等が好適に使用できる。 As the phase difference plate 406, for example, a polycarbonate resin or a cyclic olefin polymer resin is used as a film, and this film is further biaxially stretched, or a liquid crystalline monomer is applied to the film, and its molecular arrangement is changed by a photopolymerization reaction. Immobilized ones are listed. The phase difference plate 406 optically compensates for the alignment of the liquid crystal, and therefore has a refractive index characteristic opposite to that of the liquid crystal alignment. Specifically, for a TN mode liquid crystal cell, for example, “WV film” (manufactured by FUJIFILM Corporation), for an STN mode liquid crystal display cell, for example, “LC film” (manufactured by Nippon Oil Corporation), For IPS mode liquid crystal display cells, for example, a biaxial retardation film, for VA mode liquid crystal display cells, for example, a retardation plate or a biaxial retardation film combining a A plate and a C plate, a π cell For the mode liquid crystal display cell, for example, “OCB WV film” (manufactured by FUJIFILM Corporation) can be suitably used.
　以下、実施例を挙げて本発明をより詳細に説明するが、本発明はこれら実施例に限定されるものではない。なお、以下の例における光拡散フィルムのヘイズおよび表面の中心線平均粗さＲａ、光拡散層の厚さならびに用いた透光性微粒子の重量平均粒径の測定方法は次のとおりである。 Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. In the following examples, the methods for measuring the haze and surface centerline average roughness Ra of the light diffusion film, the thickness of the light diffusion layer, and the weight average particle diameter of the light-transmitting fine particles used are as follows.
　（ａ）ヘイズ
　光学的に透明な粘着剤を用いて、光拡散フィルムを、その透明基材フィルム側をガラス基板に貼合して作製した測定用サンプルを用いて測定を行なった。全ヘイズ値および内部ヘイズの測定には、ＪＩＳ　Ｋ　７１３６に準拠したヘイズ透過率計（株式会社村上色彩技術研究所製のヘイズメーター「ＨＭ－１５０」）を用いた。その結果に基づき、上記式（３）より表面ヘイズを算出した。 (A) Haze Using an optically transparent adhesive, the light diffusion film was measured using a measurement sample prepared by bonding the transparent base film side to a glass substrate. For the measurement of the total haze value and internal haze, a haze transmittance meter (haze meter “HM-150” manufactured by Murakami Color Research Laboratory Co., Ltd.) according to JIS K 7136 was used. Based on the result, the surface haze was calculated from the above formula (3).
　（ｂ）中心線平均粗さＲａ
　ＪＩＳ　Ｂ　０６０１に準拠した共焦点干渉顕微鏡（たとえば、株式会社オプティカルソリューション社製の「ＰＬμ２３００」）を用いて測定を行ない、上記式（１）に基づいて算出した。 (B) Centerline average roughness Ra
Measurement was performed using a confocal interference microscope (for example, “PLμ2300” manufactured by Optical Solution Co., Ltd.) in accordance with JIS B 0601, and calculation was performed based on the above formula (1).
　（ｃ）光拡散層の厚さ
　光拡散フィルムの厚さをＮＩＫＯＮ社製　ＤＩＧＩＭＩＣＲＯ　ＭＨ－１５（本体）およびＺＣ－１０１（カウンター）を用いて測定し、基材厚み８０μｍを測定層厚から差し引くことにより光拡散層の厚さを測定した。 (C) Light diffusing layer thickness The thickness of the light diffusing film is measured using DIGIMICRO MH-15 (main body) and ZC-101 (counter) manufactured by NIKON, and the substrate thickness of 80 μm is subtracted from the measured layer thickness. Was used to measure the thickness of the light diffusion layer.
　（ｄ）透光性微粒子の重量平均粒径および粒径の標準偏差
　コールター原理（細孔電気抵抗法）に基づき、コールターマルチサイザー（ベックマンコールター社製）を用いて測定した。 (D) Weight average particle diameter of light-transmitting fine particles and standard deviation of particle diameter Based on the Coulter principle (pore electrical resistance method), measurement was performed using a Coulter Multisizer (manufactured by Beckman Coulter).
　〔金属製エンボスロールの作製〕
　直径２００ｍｍの鉄ロール（ＪＩＳによるＳＴＫＭ１３Ａ）の表面に銅バラードめっきが施されたものを用意した。銅バラードめっきは、銅めっき層／薄い銀めっき層／表面銅めっき層から形成されるものであり、めっき層全体の厚さは、約２００μｍであった。その銅めっき表面を鏡面研磨し、さらにその研磨面に、ブラスト装置（（株）不二製作所製）を用いて、ジルコニアビーズＴＺ－Ｂ１２５（東ソー（株）製、平均粒径：１２５μｍ）を、ブラスト圧力０．０５ＭＰａ（ゲージ圧、以下同じ）、微粒子使用量１６ｇ／ｃｍ2（ロールの表面積１ｃｍ2あたりの使用量、以下同じ）でブラストし、表面に凹凸を形成した。その凹凸面に、ブラスト装置（（株）不二製作所製）を用いて、ジルコニアビーズＴＺ－ＳＸ－１７（東ソー（株）製、平均粒径：２０μｍ）を、ブラスト圧力０．１ＭＰａ、微粒子使用量４ｇ／ｃｍ2でブラストし、表面凹凸を微調整した。得られた凹凸つき銅めっき鉄ロールに対し、塩化第二銅液でエッチング処理を行なった（エッチング量：３μｍ）。その後、クロムめっき加工（クロムめっきの厚さ：４μｍ）を行ない、金属製エンボスロールを作製した。得られた金属製エンボスロールのクロムめっき面のビッカース硬度は１０００であった。ビッカース硬度は、超音波硬度計ＭＩＣ１０（Ｋｒａｕｔｋｒａｍｅｒ社製）を用い、ＪＩＳ　Ｚ　２２４４に準拠して測定した。 [Production of metal embossing roll]
The surface of a 200 mm diameter iron roll (STKM13A by JIS) was prepared by applying copper ballad plating. The copper ballad plating was formed from a copper plating layer / a thin silver plating layer / a surface copper plating layer, and the thickness of the entire plating layer was about 200 μm. The copper-plated surface is mirror-polished, and zirconia beads TZ-B125 (manufactured by Tosoh Corporation, average particle size: 125 μm) are further polished on the polished surface using a blasting device (manufactured by Fuji Seisakusho). Blasting was performed at a blast pressure of 0.05 MPa (gauge pressure, the same shall apply hereinafter) and a fine particle usage amount of 16 g / cm 2 (a usage amount per 1 cm 2 of surface area of the roll, the same applies hereinafter) to form irregularities on the surface. Using a blasting device (manufactured by Fuji Seisakusho) on the uneven surface, zirconia beads TZ-SX-17 (manufactured by Tosoh Corporation, average particle size: 20 μm), blast pressure 0.1 MPa, using fine particles Blasting was performed at an amount of 4 g / cm 2 to finely adjust the surface irregularities. The resulting copper-plated iron roll with unevenness was etched with a cupric chloride solution (etching amount: 3 μm). Then, chromium plating processing (thickness of chromium plating: 4 μm) was performed to produce a metal embossing roll. The Vickers hardness of the chrome-plated surface of the obtained metal embossing roll was 1000. The Vickers hardness was measured according to JIS Z 2244 using an ultrasonic hardness tester MIC10 (manufactured by Krautkramer).
　〔表面処理フィルムの作製〕
　（製造例１：防眩フィルムの作製）
　ペンタエリスリトールトリアクリレート６０重量部、および多官能ウレタン化アクリレート（ヘキサメチレンジイソシアネートとペンタエリスリトールトリアクリレートの反応生成物）４０重量部をプロピレングリコールモノメチルエーテル溶液に混合し、固形分濃度６０重量％となるように調整して紫外線硬化性樹脂組成物を得た。 [Production of surface-treated film]
(Production Example 1: Production of antiglare film)
60 parts by weight of pentaerythritol triacrylate and 40 parts by weight of polyfunctional urethanized acrylate (reaction product of hexamethylene diisocyanate and pentaerythritol triacrylate) are mixed in a propylene glycol monomethyl ether solution so that the solid content concentration becomes 60% by weight. To obtain an ultraviolet curable resin composition.
　次に、上記紫外線硬化性樹脂組成物の固形分１００重量部に対して、光重合開始剤である「ルシリン　ＴＰＯ」（ＢＡＳＦ社製、化学名：２，４，６－トリメチルベンゾイルジフェニルフォスフィンオキサイド）を５重量部添加し、固形分濃度が６０重量％になるようにプロピレングリコールモノメチルエーテルで希釈して塗布液を調製した。 Next, with respect to 100 parts by weight of the solid content of the UV curable resin composition, “Lucirin TPO” (manufactured by BASF, chemical name: 2,4,6-trimethylbenzoyldiphenylphosphine oxide) ) Was added, and diluted with propylene glycol monomethyl ether so that the solid content concentration was 60% by weight to prepare a coating solution.
　この塗布液を、厚さ８０μｍのトリアセチルセルロース（ＴＡＣ）フィルムである透明樹脂フィルム上に塗布し、８０℃に設定した乾燥機中で１分間乾燥させた。乾燥後の透明樹脂フィルムを、上記金属製エンボスロールの凹凸面に、紫外線硬化性樹脂組成物層がロール側となるようにゴムロールで押し付けて密着させた。この状態で透明樹脂フィルム側より、強度２０ｍＷ／ｃｍ2の高圧水銀灯からの光をｈ線換算光量で３００ｍＪ／ｃｍ2となるように照射して、紫外線硬化性樹脂組成物層を硬化させ、透明樹脂フィルム上に防眩層が形成された防眩フィルムを得た。 This coating solution was applied on a transparent resin film which is a 80 μm thick triacetyl cellulose (TAC) film, and dried for 1 minute in a drier set at 80 ° C. The dried transparent resin film was pressed and adhered to the uneven surface of the metal embossing roll with a rubber roll so that the ultraviolet curable resin composition layer was on the roll side. In this state, light from a high-pressure mercury lamp having an intensity of 20 mW / cm 2 is irradiated from the transparent resin film side so that the amount of light in terms of h-line is 300 mJ / cm 2 to cure the ultraviolet curable resin composition layer, and transparent An antiglare film having an antiglare layer formed on the resin film was obtained.
　（製造例２：反射防止フィルムの作製）
　ジペンタエリスリトールトリアクリレート１０重量部、ペンタエリスリトールテトラアクリレート１０重量部、ウレタンアクリレート（共栄社化学株式会社製「ＵＡ－３０６Ｔ」）３０重量部、光重合開始剤として「イルガキュア１８４」（チバジャパン株式会社製）２．５重量部、溶媒としてメチルエチルケトン５０重量部、酢酸ブチル５０重量部を混合し、紫外線硬化性樹脂組成物であるハードコート層形成用塗布液を調製した。この塗布液を、厚さ８０μｍのＴＡＣフィルムである透明樹脂フィルム（屈折率１．４９）上にワイヤーバーコーターにより塗布し、８０℃に設定した乾燥機中で１分間乾燥させた。乾燥後の透明樹脂フィルムに対し、メタルハライドランプを用い、１２０Ｗの出力で２０ｃｍの距離から１０秒間紫外線照射を行なうことによりハードコート層を形成した。得られたハードコート層の厚さは５μｍであり、屈折率は１．５２であった。 (Production Example 2: Production of antireflection film)
10 parts by weight of dipentaerythritol triacrylate, 10 parts by weight of pentaerythritol tetraacrylate, 30 parts by weight of urethane acrylate (“UA-306T” manufactured by Kyoeisha Chemical Co., Ltd.), “Irgacure 184” (manufactured by Ciba Japan Co., Ltd.) as a photopolymerization initiator ) 2.5 parts by weight, 50 parts by weight of methyl ethyl ketone and 50 parts by weight of butyl acetate as a solvent were mixed to prepare a coating liquid for forming a hard coat layer which is an ultraviolet curable resin composition. This coating solution was applied onto a transparent resin film (refractive index: 1.49), which is a TAC film having a thickness of 80 μm, with a wire bar coater and dried in a dryer set at 80 ° C. for 1 minute. A hard coat layer was formed on the transparent resin film after drying by irradiating with ultraviolet rays at a power of 120 W from a distance of 20 cm for 10 seconds using a metal halide lamp. The obtained hard coat layer had a thickness of 5 μm and a refractive index of 1.52.
　次に、テトラエトキシシランにイソプロピルアルコール、０．１Ｎ塩酸を加え、加水分解させることより、オリゴマーのテトラエトキシシランの重合体を含む溶液を得た。この溶液に一次粒子径が８ｎｍのアンチモンドープ酸化スズ（ＡＴＯ）微粒子を混合し、イソプロピルアルコールを加えることにより、テトラエトキシシランの重合体を２．５重量％、アンチモンドープ酸化スズ微粒子を２．５重量％含む帯電防止層形成用塗布液を得た。一方、ハードコート層が形成されたＴＡＣフィルムを、５０℃の１．５Ｎ－ＮａＯＨ水溶液に２分間浸漬させてアルカリ処理を行ない、水洗後、０．５重量％のＨ2ＳＯ4水溶液に室温で３０秒浸漬させることにより中和させ、さらに水洗し、乾燥処理を行なった。上記帯電防止層形成用塗布液を、アルカリ処理したハードコート層上にワイヤーバーコーターにより塗布し、１２０℃に設定した乾燥機中で１分間乾燥させることにより帯電防止層を形成した。得られた帯電防止層の厚さは１６３ｎｍであり、屈折率は１．５３であり、光学膜厚は２５０ｎｍであった。 Next, isopropyl alcohol and 0.1N hydrochloric acid were added to tetraethoxysilane and hydrolyzed to obtain a solution containing an oligomeric tetraethoxysilane polymer. Antimony-doped tin oxide (ATO) fine particles having a primary particle diameter of 8 nm are mixed with this solution, and isopropyl alcohol is added to obtain 2.5 wt% of tetraethoxysilane polymer and 2.5 wt.% Of antimony-doped tin oxide fine particles. A coating solution for forming an antistatic layer containing 5% by weight was obtained. On the other hand, the TAC film on which the hard coat layer is formed is immersed in a 1.5N-NaOH aqueous solution at 50 ° C. for 2 minutes for alkali treatment, washed with water, and then washed with 0.5 wt% H 2 SO 4 aqueous solution at room temperature. It was neutralized by dipping for 30 seconds, further washed with water, and dried. The antistatic layer-forming coating solution was applied onto the alkali-treated hard coat layer with a wire bar coater and dried in a drier set at 120 ° C. for 1 minute to form an antistatic layer. The resulting antistatic layer had a thickness of 163 nm, a refractive index of 1.53, and an optical film thickness of 250 nm.
　次に、テトラエトキシシランと１Ｈ，１Ｈ，２Ｈ，２Ｈ－パーフルオロオクチルトリメトキシシランの９５：５（モル比）混合物にイソプロピルアルコール、０．１Ｎ塩酸を加え、加水分解させることより、オリゴマーの有機ケイ素化合物の重合体を含む溶液を得た。この溶液に内部に空隙を有する低屈折率シリカ微粒子を混合し、イソプロピルアルコールを加えることにより、有機ケイ素化合物を２重量％、低屈折率シリカ微粒子を２重量％含む低屈折率層形成用塗布液を得た。得られた低屈折率層形成用塗布液を帯電防止層上にワイヤーバーコーターにより塗布し、１２０℃に設定した乾燥機中で１分間乾燥させることにより低屈折率層を形成した。得られた低屈折率層の厚さは９１ｎｍであり、屈折率は１．３７であり、光学膜厚は１２５ｎｍであった。以上により、透明樹脂フィルム上にハードコート層、帯電防止層、及び、低屈折率層を備える反射防止フィルムを作製した。 Next, by adding isopropyl alcohol and 0.1N hydrochloric acid to a 95: 5 (molar ratio) mixture of tetraethoxysilane and 1H, 1H, 2H, 2H-perfluorooctyltrimethoxysilane and hydrolyzing it, an organic oligomer is obtained. A solution containing a polymer of a silicon compound was obtained. A coating solution for forming a low refractive index layer containing 2 wt% of an organosilicon compound and 2 wt% of low refractive index silica fine particles by mixing low refractive index silica fine particles having voids in the solution and adding isopropyl alcohol to the solution. Got. The obtained coating solution for forming a low refractive index layer was coated on the antistatic layer with a wire bar coater and dried in a dryer set at 120 ° C. for 1 minute to form a low refractive index layer. The obtained low refractive index layer had a thickness of 91 nm, a refractive index of 1.37, and an optical film thickness of 125 nm. As described above, an antireflection film including a hard coat layer, an antistatic layer, and a low refractive index layer on a transparent resin film was produced.
　〔光拡散フィルムの作製〕
　（製造例３：光拡散フィルムＡの作製）
　ペンタエリスリトールトリアクリレート６０重量部、および多官能ウレタン化アクリレート（ヘキサメチレンジイソシアネートとペンタエリスリトールトリアクリレートの反応生成物）４０重量部をプロピレングリコールモノメチルエーテル溶液に混合し、固形分濃度６０重量％となるように調整して紫外線硬化性樹脂組成物を得た。なお、該組成物からプロピレングリコールモノメチルエーテルを除去して紫外線硬化した後の硬化物の屈折率は１．５３であった。 [Production of light diffusion film]
(Production Example 3: Production of light diffusion film A)
60 parts by weight of pentaerythritol triacrylate and 40 parts by weight of polyfunctional urethanized acrylate (reaction product of hexamethylene diisocyanate and pentaerythritol triacrylate) are mixed in a propylene glycol monomethyl ether solution so that the solid content concentration becomes 60% by weight. To obtain an ultraviolet curable resin composition. The refractive index of the cured product after removing propylene glycol monomethyl ether from the composition and curing with ultraviolet rays was 1.53.
　次に、上記紫外線硬化性樹脂組成物の固形分１００重量部に対して、第１の透光性微粒子として重量平均粒径が３．０μｍ、標準偏差が０．３９μｍであるポリスチレン系粒子を１０重量部、第２の透光性微粒子として重量平均粒径が７．２μｍ、標準偏差が０．７３μｍであるポリスチレン系粒子を３０重量部、および光重合開始剤である「ルシリン　ＴＰＯ」（ＢＡＳＦ社製、化学名：２，４，６－トリメチルベンゾイルジフェニルフォスフィンオキサイド）を５重量部添加し、固形分率が６０重量％になるようにプロピレングリコールモノメチルエーテルで希釈して塗布液を調製した。 Next, 10 polystyrene particles having a weight average particle diameter of 3.0 μm and a standard deviation of 0.39 μm are used as the first light-transmitting fine particles with respect to 100 parts by weight of the solid content of the ultraviolet curable resin composition. Parts by weight, 30 parts by weight of polystyrene particles having a weight average particle diameter of 7.2 μm and a standard deviation of 0.73 μm as the second translucent fine particles, and “Lucirin TPO” (BASF Corporation) as a photopolymerization initiator (5, parts by weight, manufactured by Chemical Name: 2,4,6-trimethylbenzoyldiphenylphosphine oxide) was added and diluted with propylene glycol monomethyl ether so that the solid content was 60% by weight to prepare a coating solution.
　この塗布液を、厚さ８０μｍのＴＡＣフィルム（透明基材フィルム）上に塗布し、８０℃に設定した乾燥機中で１分間乾燥させた後、透明基材フィルム側より、強度２０ｍＷ／ｃｍ2の高圧水銀灯からの光をｈ線換算光量で３００ｍＪ／ｃｍ2となるように照射して、紫外線硬化性樹脂組成物層を硬化させ、光拡散層と透明基材フィルムとから構成される光拡散フィルムＡを得た。 This coating solution was applied onto a TAC film (transparent substrate film) having a thickness of 80 μm, dried for 1 minute in a drier set at 80 ° C., and then strength 20 mW / cm 2 from the transparent substrate film side. Light from a high-pressure mercury lamp is irradiated so as to be 300 mJ / cm 2 in terms of the amount of h-ray conversion, the ultraviolet curable resin composition layer is cured, and light diffusion comprising a light diffusion layer and a transparent substrate film Film A was obtained.
　得られた光拡散フィルムＡの全ヘイズ、内部ヘイズ、表面ヘイズはそれぞれ、６５．８％、４８．２％、１７．６％であった。また、表面の中心線平均粗さＲａは０．４２μｍであり、光拡散層の厚さは１０．９μｍであった。 The total haze, internal haze, and surface haze of the obtained light diffusion film A were 65.8%, 48.2%, and 17.6%, respectively. Further, the center line average roughness Ra of the surface was 0.42 μm, and the thickness of the light diffusion layer was 10.9 μm.
　＜実施例１＞
　製造例３で得られた光拡散フィルムＡの透明基材フィルム表面にコロナ処理を施した後、コロナ処理面に紫外線硬化性エポキシ樹脂と光カチオン重合開始剤とを含む紫外線硬化性接着剤を厚み４μｍで塗工した。一方、保護フィルムとしてのＴＡＣフィルム（厚さ８０μｍ）の片面にコロナ処理を施した後、コロナ処理面に上記と同じ紫外線硬化性接着剤を厚み４μｍで塗工した。ついで、一軸延伸したポリビニルアルコール系樹脂フィルムにヨウ素を吸着配向させることにより形成した偏光フィルムの一方の面に上記光拡散フィルムＡをその接着剤層を介して積層するとともに、他方の面に上記保護フィルムをその接着剤層を介して積層し、一対のニップロールで挟圧した。その後、保護フィルム側から紫外線を照射し、両方の接着剤層を硬化させて光拡散性偏光板を得た。 <Example 1>
After the corona treatment is applied to the surface of the transparent base film of the light diffusion film A obtained in Production Example 3, an ultraviolet curable adhesive containing an ultraviolet curable epoxy resin and a cationic photopolymerization initiator is thickened on the corona treatment surface. Coating was performed at 4 μm. On the other hand, after a corona treatment was applied to one side of a TAC film (thickness 80 μm) as a protective film, the same UV curable adhesive as described above was applied to the corona treatment surface with a thickness of 4 μm. Next, the light diffusing film A is laminated on one surface of a polarizing film formed by adsorbing and orienting iodine on a uniaxially stretched polyvinyl alcohol-based resin film, and the protection is provided on the other surface. The film was laminated through the adhesive layer and sandwiched between a pair of nip rolls. Then, the ultraviolet-ray was irradiated from the protective film side, both the adhesive bond layers were hardened, and the light diffusable polarizing plate was obtained.
　次に、上記光拡散性偏光板における光拡散フィルムＡの光拡散層上に、製造例１で得られた防眩フィルムをその透明樹脂フィルム側が貼合面となるように、汎用のアクリル系透明粘着剤を介して積層し、防眩処理が施された光拡散性偏光板を得た。 Next, on the light diffusion layer of the light diffusion film A in the light diffusion polarizing plate, a general-purpose acrylic transparent so that the antiglare film obtained in Production Example 1 is a bonding surface on the transparent resin film side. A light diffusing polarizing plate laminated with an adhesive and subjected to an antiglare treatment was obtained.
　＜実施例２＞
　防眩フィルムの代わりに、製造例２で得られた反射防止フィルムを用いたこと以外は、実施例１と同様にして反射防止処理が施された光拡散性偏光板を得た。 <Example 2>
Instead of the antiglare film, a light diffusing polarizing plate subjected to an antireflection treatment was obtained in the same manner as in Example 1 except that the antireflection film obtained in Production Example 2 was used.
　＜比較例１＞
　光拡散フィルムＡと防眩フィルムとを粘着剤層を介して積層した上記積層体（実施例１で使用したもの）の代わりに、光拡散フィルムＡの光拡散層表面を、上記金属製エンボスロールの凹凸面にゴムロールで押し付けることにより、光拡散層に防眩処理を施したフィルムを用いたこと以外は、実施例１と同様にして防眩処理が施された光拡散性偏光板を得た。 <Comparative Example 1>
Instead of the laminate (used in Example 1) in which the light diffusion film A and the antiglare film are laminated via an adhesive layer, the surface of the light diffusion layer of the light diffusion film A is replaced with the metal embossing roll. A light diffusing polarizing plate subjected to an antiglare treatment was obtained in the same manner as in Example 1 except that a film having an antiglare treatment applied to the light diffusion layer was used by pressing the concavo-convex surface with a rubber roll. .
　＜比較例２＞
　光拡散フィルムＡと反射防止フィルムとを粘着剤層を介して積層した上記積層体（実施例２で使用したもの）の代わりに、光拡散フィルムＡの光拡散層表面に、上記製造例２に記載の方法に従って、帯電防止層、低屈折率層を順次形成することにより、光拡散層に反射防止処理を施したフィルムを用いたこと以外は、実施例２と同様にして反射防止処理が施された光拡散性偏光板を得た。 <Comparative Example 2>
Instead of the above laminate (used in Example 2) in which the light diffusion film A and the antireflection film are laminated via an adhesive layer, the surface of the light diffusion layer of the light diffusion film A has In accordance with the method described above, the anti-reflection treatment was performed in the same manner as in Example 2 except that the anti-reflection layer and the low-refractive index layer were sequentially formed, and the light diffusion layer was subjected to an anti-reflection treatment. The obtained light diffusable polarizing plate was obtained.
　（光拡散性偏光板の表面処理特性の評価）
　（１）防眩性の評価
　防眩処理が施された実施例１および比較例１の光拡散性偏光板について、防眩性の評価を行なった。具体的には、光拡散性偏光板を蛍光灯のついた明るい室内で凹凸面（防眩層表面）側から目視観察し、蛍光灯の映り込みの有無を確認した。蛍光灯の映り込みがフィルム全面にわたって見られないものをＡ、フィルム面の少なくとも一部に蛍光灯の映り込みが認められるものをＢとした。結果を表１に示す。 (Evaluation of surface treatment characteristics of light diffusing polarizing plate)
(1) Evaluation of antiglare property About the light diffusable polarizing plate of Example 1 and the comparative example 1 in which the glare-proof process was performed, anti-glare property was evaluated. Specifically, the light diffusing polarizing plate was visually observed from the uneven surface (antiglare layer surface) side in a bright room with a fluorescent lamp to confirm the presence or absence of reflection of the fluorescent lamp. The case where the reflection of the fluorescent lamp was not observed over the entire surface of the film was A, and the case where the reflection of the fluorescent lamp was observed on at least a part of the film surface was indicated as B. The results are shown in Table 1.
　（２）色ムラの評価
　反射防止処理が施された実施例２および比較例２の光拡散性偏光板について、色ムラの評価を行なった。具体的には、保護フィルム表面を黒色艶消しスプレーにより黒色に着色した光拡散性偏光板を、蛍光灯のついた明るい室内で低屈折率層表面側から目視観察し、色ムラの有無を確認した。色ムラがフィルム全面にわたって見られないものをＡ、フィルム面の少なくとも一部に色ムラが認められるものをＢとした。結果を表１に示す。色ムラは、反射防止処理面における面内不均一性に起因して、上記目視観察において面内が虹色に見える現象であり、このような色ムラが発生する場合、反射防止機能が不良であると判断される。 (2) Evaluation of color unevenness Color unevenness was evaluated for the light diffusing polarizing plates of Example 2 and Comparative Example 2 subjected to the antireflection treatment. Specifically, a light-diffusing polarizing plate with the protective film surface colored black by a black matte spray is visually observed from the surface side of the low refractive index layer in a bright room with a fluorescent lamp to confirm the presence or absence of color unevenness. did. A case where no color unevenness was observed over the entire film surface was designated as A, and a case where color unevenness was observed on at least a part of the film surface was designated as B. The results are shown in Table 1. Color unevenness is a phenomenon in which the inside of the surface looks rainbow-colored in the above visual observation due to in-plane non-uniformity on the antireflection treatment surface. When such color unevenness occurs, the antireflection function is poor. It is judged that there is.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　表１に示されるように、本発明に係る光拡散性偏光板によれば、直接表面処理を施すことが困難な光拡散フィルムに対しても、優れた表面処理特性を付与できることがわかる。 As shown in Table 1, according to the light diffusable polarizing plate according to the present invention, it can be seen that excellent surface treatment characteristics can be imparted even to a light diffusion film that is difficult to be directly surface treated.
　１００，４０５…光拡散性偏光板、１０１…偏光フィルム、１０２…光拡散フィルム、１０３…表面処理フィルム、１０４…粘着剤層または接着剤層、１０５…透明基材フィルム、１０６…光拡散層、１０６ａ…透光性樹脂、１０６ｂ…透光性微粒子、１０７…透明樹脂フィルム、１０８…表面処理層、１０９…保護フィルム、３０１…巻き出し装置、３０２…塗工装置、３０３…バックアップロール、３０４…乾燥機、３０５…鏡面金属製ロールまたはエンボス加工用金属製ロール、３０６…ニップロール、３０７…剥離ロール、３０８…紫外線照射装置、３０９…巻き取り装置、４００，４００’…液晶表示装置、４０１…液晶セル、４０２…バックライト装置、４０３…光拡散手段、４０３ａ…光拡散板、４０３ｂ，４０３ｂ’…光偏向板、４０４…バックライト側偏光板、４０６…位相差板、４１１ａ，４１１ｂ…透明基板、４１２…液晶層、４２１…ケース、４２２…冷陰極管、４３０…基材、４４０…光拡散剤、４５０，４５０’…線状プリズム、４５１，４５１’…線状プリズムの稜線。 DESCRIPTION OF SYMBOLS 100,405 ... Light diffusable polarizing plate, 101 ... Polarizing film, 102 ... Light diffusing film, 103 ... Surface treatment film, 104 ... Adhesive layer or adhesive layer, 105 ... Transparent base film, 106 ... Light diffusing layer, 106a ... translucent resin, 106b ... translucent fine particles, 107 ... transparent resin film, 108 ... surface treatment layer, 109 ... protective film, 301 ... unwinding device, 302 ... coating device, 303 ... backup roll, 304 ... Dryer, 305 ... mirror surface metal roll or embossing metal roll, 306 ... nip roll, 307 ... peeling roll, 308 ... ultraviolet irradiation device, 309 ... winding device, 400, 400 '... liquid crystal display device, 401 ... liquid crystal Cell, 402 ... Backlight device, 403 ... Light diffusing means, 403a ... Light diffusing plate, 403b, 403b '... Light Direction plate, 404 ... Backlight side polarizing plate, 406 ... Phase difference plate, 411a, 411b ... Transparent substrate, 412 ... Liquid crystal layer, 421 ... Case, 422 ... Cold cathode tube, 430 ... Base material, 440 ... Light diffusing agent, 450, 450 '... linear prism, 451, 451' ... ridge line of linear prism.

Claims (10)

  1. 　偏光フィルムと、
    　前記偏光フィルム上に積層される光拡散フィルムと、
    　前記光拡散フィルム上に積層される表面処理フィルムと、
    を備え、
    　前記光拡散フィルムは、光拡散層を有し、
    　前記光拡散層の表面のうち、前記表面処理フィルムに近い方の表面の中心線平均粗さＲａが０．１μｍ以上１μｍ未満であり、
    　前記表面処理フィルムは、一方の表面に光学的処理が施された透明樹脂フィルムから形成され、
    　前記光拡散層と、前記表面処理フィルムとが、粘着剤層または接着剤層を介して互いに貼合されている光拡散性偏光板。     A polarizing film;
    A light diffusion film laminated on the polarizing film;
    A surface treatment film laminated on the light diffusion film;
    With
    The light diffusion film has a light diffusion layer,
    Among the surfaces of the light diffusion layer, the center line average roughness Ra of the surface closer to the surface treatment film is 0.1 μm or more and less than 1 μm,
    The surface treatment film is formed from a transparent resin film having an optical treatment on one surface,
    The light diffusable polarizing plate by which the said light-diffusion layer and the said surface treatment film are bonded together through the adhesive layer or the adhesive bond layer.
  2. 　前記表面処理フィルムは、光学的処理が施されていない面を有し、
    　前記光拡散層と前記表面処理フィルムの光学的処理が施されていない面とが、粘着剤層または接着剤層を介して互いに貼合されて、
    　前記光拡散層と前記表面処理フィルムとが貼合されている請求項１に記載の光拡散性偏光板。     The surface treatment film has a surface not subjected to optical treatment,
    The light diffusion layer and the surface of the surface treatment film not subjected to optical treatment are bonded to each other via an adhesive layer or an adhesive layer,
    The light diffusable polarizing plate of Claim 1 with which the said light-diffusion layer and the said surface treatment film are bonded.
  3. 　前記光学的処理は、防眩処理または反射防止処理である請求項１または２に記載の光拡散性偏光板。 3. The light diffusing polarizing plate according to claim 1, wherein the optical treatment is an antiglare treatment or an antireflection treatment.
  4. 　前記光拡散フィルムは、透明基材フィルムをさらに備え、
    　前記透明基材フィルム上に前記光拡散層が積層され、
    　前記光拡散層は、透光性樹脂と、前記透光性樹脂中に分散されている透光性微粒子とを含む請求項１～３のいずれか一項に記載の光拡散性偏光板。     The light diffusion film further comprises a transparent substrate film,
    The light diffusion layer is laminated on the transparent substrate film,
    The light diffusing polarizing plate according to any one of claims 1 to 3, wherein the light diffusing layer includes a translucent resin and translucent fine particles dispersed in the translucent resin.
  5. 　前記光拡散層は、前記透明基材フィルム上に、前記透光性微粒子が分散された樹脂液を塗布して形成される請求項４に記載の光拡散性偏光板。 The light diffusing polarizing plate according to claim 4, wherein the light diffusing layer is formed by applying a resin liquid in which the translucent fine particles are dispersed on the transparent substrate film.
  6. 　前記光拡散層は、前記透光性微粒子が分散された樹脂液を前記透明基材フィルム上に塗布し、前記樹脂液から形成される層の表面に金型の鏡面または凹凸面を転写して形成される請求項４に記載の光拡散性偏光板。 The light diffusion layer is formed by applying a resin liquid in which the translucent fine particles are dispersed on the transparent base film, and transferring a mirror surface or an uneven surface of a mold to the surface of the layer formed from the resin liquid. The light diffusable polarizing plate of Claim 4 formed.
  7. 　バックライト装置と、光拡散手段と、バックライト側偏光板と、液晶セルと、請求項１～６のいずれか一項に記載の光拡散性偏光板とをこの順で備え、
    　前記光拡散性偏光板は、前記偏光フィルムが前記表面処理フィルムよりも前記液晶セルに近くなるように、配置される液晶表示装置。     A backlight device, a light diffusing means, a backlight side polarizing plate, a liquid crystal cell, and the light diffusing polarizing plate according to any one of claims 1 to 6 are provided in this order,
    The light diffusing polarizing plate is a liquid crystal display device arranged so that the polarizing film is closer to the liquid crystal cell than the surface treatment film.
  8. 　前記光拡散手段からの出射光は、前記液晶セルの光入射面の垂線方向から７０°傾いた方向の輝度が前記垂線方向の輝度に対して２０％以下である配光特性を有し、かつ、非平行光を含む、請求項７に記載の液晶表示装置。 The light emitted from the light diffusing means has a light distribution characteristic in which the luminance in a direction inclined by 70 ° from the normal direction of the light incident surface of the liquid crystal cell is 20% or less with respect to the luminance in the normal direction, and The liquid crystal display device according to claim 7, comprising non-parallel light.
  9. 　前記光拡散手段は、前記バックライト装置側から、光拡散板と、光偏向板とをこの順で備える請求項７または８に記載の液晶表示装置。 The liquid crystal display device according to claim 7 or 8, wherein the light diffusion means includes a light diffusion plate and a light deflection plate in this order from the backlight device side.
  10. 　前記液晶セルは、ＴＮ方式液晶セル、ＩＰＳ方式液晶セルまたはＶＡ方式液晶セルである請求項７～９のいずれか一項に記載の液晶表示装置。 The liquid crystal display device according to any one of claims 7 to 9, wherein the liquid crystal cell is a TN liquid crystal cell, an IPS liquid crystal cell, or a VA liquid crystal cell.
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