JP2012078420A - Light diffusing polarizer plate, and liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light diffusing polarizer plate in which a surface treatment film exhibiting various functions is laminated on a light diffusing layer of a light diffusing film via an adhesive layer, and even when surface roughness of the light diffusing layer is large, air bubbles are not tangled into the surface roughness of the light diffusing layer, thereby preventing discoloration and achieving good visibility, and a liquid crystal display device using the light diffusing polarizer plate.SOLUTION: The light diffusing polarizer plate includes a polarizer film 101, the light diffusing film 102 laminated on the polarizer film, and the surface treatment film 103 laminated on the light diffusing film. The light diffusing film 102 has the light diffusing layer 106 with surface center line average roughness Ra of 0.1 μm or more and less than 1 μm. The light diffusing layer 106 and the surface treatment film 103 are bonded together via the adhesive layer 104 which has a storage elastic modulus of less than 1.0×10Pa at 25°C. The liquid crystal display device using the light diffusing polarizer plate is also provided.

Description

  The present invention relates to a light diffusing polarizing plate and a liquid crystal display device using the same.

  In recent years, application of liquid crystal display devices to mobile phones, personal computer monitors, televisions, liquid crystal projectors, and the like is rapidly progressing. In general, a liquid crystal display device includes a backlight device, a liquid crystal panel including a liquid crystal cell, a back side polarizing plate disposed on the backlight side of the liquid crystal cell, and a front side polarizing plate disposed on the viewing side of the liquid crystal cell. , Including.

  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.

  As a method for solving such a problem of viewing angle characteristics, a technique for imparting a light diffusion function to a front-side polarizing plate is conventionally known. For example, Japanese Patent Application Laid-Open No. 2009-301014 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2010-160527 (Patent Document 2) describe a polarizing plate having a relatively high light diffusibility (Patent Document) on the front side of a liquid crystal cell. 1 and 2, which are expressed as “second light diffusion layer”. 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). ).

JP 2009-301014 A JP 2010-160527 A

  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. Optical processing such as anti-glare processing or anti-reflection processing for preventing or reducing reflection of external light incident on the display surface may be performed.

  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 an extremely large protrusion, and is centerline average according to JIS B 0601. When expressed by the roughness Ra, the surface roughness may be 0.1 μm or more. In such a case, it is difficult to directly apply the optical treatment as described above to the surface of the light diffusion layer. Or, even if the optical treatment itself can be directly performed, a predetermined function such as an anti-glare function or an anti-reflection function may not be exhibited well.

  In addition, by applying a surface-treated film that has been optically treated to the surface of the resin film that serves as the base material to the light diffusion layer using an adhesive, a predetermined function such as an antiglare function or an antireflection function is provided. However, when the surface roughness of the light diffusing layer is 0.1 μm or more as described above, bubbles are caught in the surface irregularities of the light diffusing layer during bonding, and the liquid crystal display device When applied, dot-shaped color loss may occur and visibility may be reduced.

  Accordingly, an object of the present invention is a light diffusing polarizing plate in which a surface treatment film exhibiting an antiglare function or an antireflection function is laminated on a light diffusing layer of a light diffusing film via an adhesive layer, Even when the surface roughness of the layer is as large as 0.1 μm or more, a light diffusing polarizing plate having good visibility without causing color loss without causing air bubbles to bite into the surface irregularities of the light diffusing layer, and this An object of the present invention is to provide a liquid crystal display device using the above.

The present invention relates to a polarizing film, a light diffusing film laminated on the polarizing film, and a surface-treated film having an optical treatment applied to one surface of a transparent resin film laminated on the light diffusing film. The light diffusion film has a light diffusion layer having a surface centerline average roughness Ra of 0.1 μm or more and less than 1 μm, and the light diffusion layer of the light diffusion film and the surface treatment film are 25 Provided is a light diffusing polarizing plate which is bonded to each other through an adhesive layer having a storage elastic modulus at ° C. of less than 1.0 × 10 ⁶ Pa. The storage elastic modulus at 25 ° C. of the pressure-sensitive adhesive layer is preferably 1.0 × 10 ⁵ Pa or more.

  In the light diffusable polarizing plate of this invention, it is preferable that the light-diffusion layer and the surface where the optical treatment of the surface treatment film is not performed are mutually bonded through the said adhesive layer.

  The surface-treated film is, for example, an antiglare film in which an antiglare treatment is performed on one surface of the transparent resin film, or an antireflection film in which an antireflection treatment is performed on one surface of the transparent resin film. be able to.

  The light diffusing film is preferably provided with a transparent base film and a light diffusing layer laminated on the transparent base film in which translucent fine particles are dispersed. 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 diffusing layer is formed by applying a resin liquid in which translucent fine particles are dispersed on a transparent substrate film, and then transferring the mirror surface or the uneven surface of the mold to the surface of the layer made of the resin liquid. May be formed.

  Moreover, this invention provides a liquid crystal display device provided with a backlight apparatus, a light-diffusion means, a backlight side polarizing plate, a liquid crystal cell, and the said light diffusable 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 side faces the liquid crystal cell.

  In the liquid crystal display device of the present invention, the emitted light from the light diffusing means has a 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 to have light distribution characteristics and include non-parallel light.

  The light diffusing means may 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) liquid crystal cell, an IPS (In-Plane Switching) liquid crystal cell, a VA (Vertical Alignment) liquid crystal cell, or the like can be used.

  According to the present invention, it is possible to provide a light diffusable polarizing plate that has no air bubbles in the surface irregularities of the light diffusing layer and thus has no color loss and good visibility. The light diffusable polarizing plate of the present invention has high light diffusibility and also exhibits other optical functions such as an antiglare function and an antireflection function. The liquid crystal display device of the present invention to which the light diffusing polarizing plate is applied has high viewing angle characteristics and also has other optical functions imparted to the light diffusing polarizing plate, and is excellent in visibility.

It is a schematic sectional drawing which shows a preferable example of the light diffusable polarizing plate of this invention. It is the schematic which shows an example of the apparatus for manufacturing a light-diffusion film. It is a schematic sectional drawing which shows a preferable example of the liquid crystal display device of this invention. It is a schematic sectional drawing which shows an example of a light-diffusion means. It is a schematic sectional drawing which shows another example of a light-diffusion means. 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. It is an example of a method for measuring the luminance value in the direction of 70 ° with respect to the normal line of the light incident surface of the liquid crystal cell for the light diffusion means. It is a figure explaining the definition of non-parallel light. It is a schematic sectional drawing which shows another preferable example of the liquid crystal display device of this invention.

<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. 1 according to the present invention includes a polarizing film 101, a light diffusing film 102 having a light diffusing layer 106 laminated on the polarizing film 101, and a laminated film on the light diffusing film 102. A surface treatment film 103 made of a transparent resin film 107 that has been subjected to optical treatment on one surface (specifically, a surface treatment layer 108 is provided), and light diffusion of the light diffusion film 102 The layer 106 and the surface treatment film 103 are bonded to each other with the pressure-sensitive adhesive layer 104 interposed therebetween.

  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. 106 is a resin layer in which translucent fine particles 106a are dispersed in translucent resin 106b. The light diffusion film 102 is laminated on the polarizing film 101 so that the transparent base film 105 side faces the polarizing film 101. The light diffusion film 102 has a center line average roughness Ra according to JIS B 0601 on the surface of the light diffusion layer 106 of 0.1 μm or more and less than 1 μm.

  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 (a surface on which the surface treatment film 103 is not subjected to optical treatment), and is a light diffusion film through the adhesive layer 104. The light diffusion layer 106 of 102 is bonded.

  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.

According to the light diffusable polarizing plate 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 in which the surface treated layer 108 is formed on the transparent resin film 107 are 25 Since the storage elastic modulus at a temperature of less than 1.0 × 10 ⁶ Pa is bonded through the relatively small pressure-sensitive adhesive layer 104, the center line average roughness Ra of the surface of the light diffusion layer 106 is 0.1 μm or more. Even in this case, there is no air bubble mixing between the surface irregularities of the light diffusion layer 106 and the pressure-sensitive adhesive layer 104, so that when applied to a liquid crystal display device, dot-shaped color loss does not occur and good visibility can be obtained. it can. Moreover, since the light-diffusion layer 106 and the surface treatment film 103 can be joined with sufficient adhesiveness, the durability of the light-diffusible polarizing plate can be improved. Further, the bonding of the surface treatment film 103 with the pressure-sensitive adhesive layer ensures that the surface treatment film 103 having a desired optical function is formed on the light diffusion layer 106 and that the surface treatment layer 108 has a surface shape of the light diffusion layer 106. It enables stacking while completely eliminating the influence on the structure and shape. Therefore, the light diffusing polarizing plate of the present invention exhibits a predetermined optical function by the surface treatment layer 108 as well as a light diffusing function.

Hereinafter, the light diffusable polarizing plate of the present invention will be described in more detail.
(Polarizing film)
As the polarizing film 101, for example, a dichroic dye or iodine is adsorbed and oriented on a film made of polyvinyl alcohol resin, polyvinyl acetate resin, ethylene / vinyl acetate (EVA) resin, polyamide resin, polyester resin, or the like. Examples thereof include a polyvinyl alcohol / polyvinylene copolymer containing a molecular chain oriented with a dichroic dehydrated product of polyvinyl alcohol (polyvinylene) in a molecularly oriented polyvinyl alcohol film. 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. Although there is no restriction | limiting in particular in the thickness of the polarizing film 101, From viewpoints, such as thickness reduction of a light diffusable polarizing plate, 100 micrometers or less are preferable, More preferably, it is 10-50 micrometers, More preferably, it is 25-35 micrometers.

(Light diffusion film)
As shown in FIG. 1, the light diffusion film 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. The resin 106b is preferably made of a resin layer in which translucent fine particles (light diffusing agent) 106a are dispersed.

  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. As the plastic film, those having appropriate transparency and mechanical strength are preferable. Specifically, cellulose acetate resins such as TAC (triacetyl cellulose), acrylic resins, polycarbonate resins, and polyester systems such as polyethylene terephthalate. Resin etc. are mentioned. The thickness of the transparent substrate film 105 is, for example, 10 to 500 μm, and preferably 20 to 300 μm.

  The light diffusion layer 106 is a layer that uses a light-transmitting resin 106b as a base material, and light-transmitting fine particles 106a are dispersed in the light-transmitting resin 106b. The translucent resin 106b is not particularly limited as long as it has translucency. For example, a cured product of an ionizing radiation curable resin such as an ultraviolet curable resin or an electron beam curable resin; Cured product; thermoplastic resin; cured product of metal alkoxide. Among these, a cured product of an ionizing radiation curable resin is preferable because high hardness and scratch resistance can be imparted. In the case of using an ionizing radiation curable resin, a thermosetting resin, or a metal alkoxide, the translucent resin 106b is formed by curing the resin by irradiation or heating with ionizing radiation.

  Examples of the ionizing radiation curable resin include polyfunctional acrylates such as polyhydric alcohol acrylic acid or methacrylic acid ester; polyisocyanates synthesized from diisocyanate, polyhydric alcohol and acrylic acid or methacrylic acid hydroxy ester, and the like. Examples include functional urethane acrylate. Besides these, polyether resins having an acrylate functional group, polyester resins, epoxy resins, alkyd resins, spiroacetal resins, polybutadiene resins, polythiol polyene resins, and the like can also be used.

  Examples of the thermosetting resin include a phenol resin, a urea melamine resin, an epoxy resin, an unsaturated polyester resin, and a silicone resin, in addition to a thermosetting urethane resin composed of an acrylic polyol and an isocyanate prepolymer.

  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.

  As the metal alkoxide, a silicon oxide matrix or the like using a silicon alkoxide material as a raw 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.

  Further, as the light transmissive fine particles 106a, a light diffusing agent made of light transmissive organic fine particles or inorganic fine particles can be used. For example, organic fine particles made of 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. Examples include inorganic fine particles. Organic polymer balloons and glass hollow beads can also be used. The translucent fine particles 106a 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 106a may be any of a spherical shape, a flat shape, a plate shape, a needle shape, an indefinite shape, etc., but a spherical shape or a substantially spherical shape is preferable.

  The weight average particle diameter of the translucent fine particles 106a is preferably 0.5 to 15 μm, and more preferably 4 to 8 μm. When the weight average particle diameter of the light-transmitting fine particles 106a is less than 0.5 μm, the light diffusing property of the light diffusing film 102 becomes insufficient, and as a result, when a light diffusing polarizing plate is applied to a liquid crystal display device, Sufficient wide viewing angle performance may not be obtained. Moreover, when the weight average particle diameter exceeds 15 μm, sufficient light diffusibility may not be obtained. The translucent fine particles 106a preferably have a ratio of standard deviation of particle diameter to weight average particle diameter (standard deviation / weight average particle diameter) of 0.5 or less, 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 surface of the light diffusion layer 106 is 1 μm or more. Or the surface haze of the light diffusing film 102 may deviate from a preferable range described later. The weight average particle diameter and the standard deviation of the particle diameter of the translucent fine particles 106a are measured using a Coulter Multisizer (manufactured by Beckman Coulter, Inc.) based on the Coulter principle (pore electrical resistance method).

  The content of the translucent fine particles 106a in the light diffusion layer 106 is preferably 20 parts by weight or more and 100 parts by weight or less, more preferably 20 parts by weight or more and 70 parts by weight with respect to 100 parts by weight of the translucent resin 106b. Part or less, more preferably 25 parts by weight or more and 60 parts by weight or less, and particularly preferably 25 parts by weight or more and 50 parts by weight or less. When the content of the light transmissive fine particles 106a 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 106a 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. In the present invention, since the surface treatment film 103 is bonded to the light diffusion layer 106 via the pressure-sensitive adhesive layer 104, a relatively large amount of light-transmitting fine particles (light diffusion agent) is contained in the light diffusion layer. In addition, it is possible to prevent the occurrence of color loss by preventing bubbles from being mixed, and without failing the structure and shape necessary for the surface treatment layer to exhibit a predetermined optical function reliably and easily. The surface treatment layer can be applied to the light diffusing polarizing plate.

  The difference in refractive index between the translucent fine particles 106a and the translucent resin 106b is preferably in the range of 0.04 to 0.15. By setting the difference in refractive index between the light-transmitting fine particles 106a and the light-transmitting resin 106b within the above range, moderate internal scattering occurs due to the difference in refractive index, and a light diffusive film with moderately high light diffusibility is obtained. be able to.

  Moreover, it is preferable that the surface (surface on the opposite side to the transparent base film 105) of the light-diffusion layer 106 is formed only by the translucent resin 106b. That is, it is preferable that the translucent fine particles 106 a do not protrude from the surface of the light diffusion layer 106 and are completely buried in the light diffusion layer 106. For this reason, the thickness of the light diffusion layer 106 is preferably 1 to 3 times the weight average particle diameter of the translucent fine particles 106a. When the thickness of the light diffusing layer 106 is less than 1 times the weight average particle diameter of the translucent fine particles 106a, when the light diffusing polarizing plate is applied to the liquid crystal display device, the screen is diffused due to surface irregular reflection of the light diffusing layer. There may be a so-called “whiteness” in which the entire image appears whitish. Further, when the thickness of the light diffusion layer 106 exceeds three times the weight average particle diameter of the translucent fine particles 106a, 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 is applied to the liquid crystal display device, the front contrast may be lowered.

  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 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 curling generated in the produced light diffusing film becomes large, and the handleability in the production process of the light diffusing polarizing plate may be lowered.

  The center line average roughness Ra according to JIS B 0601 of the surface of the light diffusion layer 106 (surface opposite to the transparent substrate film 105) is 0.1 μm or more and less than 1 μm, preferably 0.2 μm or more and 0.5 μm. Is less than. When the center line average roughness Ra on the surface of the light diffusion layer 106 is 1 μm or more, whitishness becomes remarkable. According to the present invention, even if the center line average roughness Ra is 0.1 μm or more, and even 0.2 μm or more, the surface treatment exhibits a good optical function without causing a problem of color loss due to air bubbles mixing. A layer can be applied 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 average line, the x-axis is extracted in the direction of the average line 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):

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 Solutions Co., Ltd.) in accordance with JIS B 0601. Can be calculated.

The light diffusion film 102 preferably has a total haze of 40% to 70% and an internal haze of 40% to 70%. Moreover, it is preferable that the surface haze resulting from the surface shape of the light-diffusion layer 106 is less than 6%. “Total haze” is the total light transmittance (Tt) representing the total amount of light transmitted through the light diffusing film and the diffused light transmittance (Td) diffused and transmitted by the light diffusing film. From the ratio, the following formula (2):
Total haze (%) = (Td / Tt) × 100 (2)
Is required.

  The total light transmittance (Tt) is the sum of the parallel light transmittance (Tp) and the diffused 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 according to JIS K 7361.

  The “internal haze” of the light diffusion film is a haze other than the haze (surface haze) caused by the surface shape of the light diffusion layer 106 among all the hazes.

  When the total haze and / or internal haze is less than 40%, the light scattering property is insufficient, and sufficient wide viewing angle performance tends to be hardly obtained. Further, when the total haze and / or internal haze exceeds 70%, light scattering becomes strong, and the front contrast may be lowered when the light diffusing polarizing plate is applied to the liquid crystal display device. Further, when the total haze and / or internal haze exceeds 70%, the transparency of the light diffusion film 102 tends to be impaired. The total haze and internal haze are each preferably 50% or more and 65% or less.

  Moreover, when the surface haze resulting from the surface shape of the light-diffusion layer 106 is 6% or more, it exists in the tendency for whitening to occur easily by surface irregular reflection. In order to prevent whitening more effectively, the surface haze is more preferably 3% or less.

  Specifically, the total haze, internal haze, and surface haze of the light diffusion film 102 are measured as follows. That is, first, in order to prevent warping of the film, the light diffusion film 102 is pasted on the glass substrate using an optically transparent adhesive so that the light diffusion layer 106 becomes the surface. In combination, a measurement sample is prepared, and the total haze value of the measurement sample is measured. The total haze value is determined by 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, and a total light transmittance (Tt) and diffused light transmission. The rate (Td) is measured and calculated by the above equation (2).

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. The haze can be regarded as “internal haze” of the light diffusing film 102 because the surface haze due to the surface shape of the light diffusing layer 106 is almost canceled by the bonded triacetyl cellulose film. 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.

  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.

  Next, a method for manufacturing the light diffusion film 102 will be described. The light diffusion film 102 can be formed by a method of applying a resin liquid in which translucent fine particles 106 a are dispersed on the transparent base film 105.

  The resin liquid includes the light-transmitting fine particles 106a, the light-transmitting resin 106b constituting the light diffusion layer 106 or a resin (for example, ionizing radiation curable resin, thermosetting resin, or metal alkoxide) that forms this, and as necessary. Accordingly, other components such as a solvent are included. In the case where an ultraviolet curable resin is used as the resin that forms the translucent resin 106b, 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 '-Biimidazole, 10-butyl-2-chloroacridone, 2-ethylanthraquinone, benzyl, 9,10-phenanthrenequinone, camphorquinone, methyl phenylglyoxylate, titanocene compound and the like can also be used. The usage-amount of a photoinitiator is 0.5-20 weight part normally with respect to 100 weight part of resin contained in a resin liquid, Preferably, it is 1-5 weight part. In order to make the optical properties and the surface shape of the light diffusion film 102 uniform, it is preferable that the dispersion of the translucent fine particles 106a in the resin solution is an isotropic dispersion.

  Application of the resin liquid onto the transparent substrate film 105 can be performed by, for example, 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. . In 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 106a. It is preferable to do.

  Various surface treatments may be applied to the surface (light diffusion layer side surface) of the transparent substrate film 105 for the purpose of improving the coating property of the resin liquid or improving the adhesion to 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.

  In order to improve the adhesion between the transparent substrate film 105 and the polarizing film 101, it is preferable to subject the surface of the transparent substrate film 105 opposite to the light diffusion layer 106 to the surface treatment as described above. .

  The light diffusion film 102 is a method in which a resin liquid in which translucent fine particles 106a are dispersed is applied onto a transparent substrate film 105, and then a mirror surface or an uneven surface of a mold is transferred to the surface of the layer made of the resin liquid. Can also be formed. 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 made of the resin liquid as necessary after the resin liquid is applied. It can also be formed by transferring the mirror surface or uneven surface by bringing the uneven surface of the mold having a mirror surface or uneven surface (embossing mold) into close contact. The mirror surface mold may be a mirror surface metal roll, and the embossing mold may be an embossing metal roll.

  When ionizing radiation curable resin, thermosetting resin or metal alkoxide is used as the resin for forming the translucent resin 106b, a layer made of the above resin solution is formed and dried (removing the solvent) as necessary. Depending on the condition, the surface of the layer made of the resin liquid is in close contact with or close to the mold mirror surface or uneven surface, and then irradiated with ionizing radiation (when using ionizing radiation curable resin) or heated (thermosetting) The layer made of the resin liquid is cured by using a mold resin or metal alkoxide. The ionizing radiation can be appropriately selected from ultraviolet rays, electron beams, near ultraviolet rays, visible light, 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.

  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 arc, and a metal halide lamp are preferably used.

  Further, as the electron beam, 50 to 1000 keV emitted from various electron beam accelerators such as a cockroft Walton type, a bandegraph type, a resonance transformation type, an insulation core transformation type, a linear type, a dynamitron type, and a high frequency type, preferably 100 Mention may be made of electron beams having an energy of ˜300 keV.

  Next, a preferred embodiment for manufacturing the light diffusion film 102 will be described. In the production method according to the preferred embodiment, in order to continuously produce the light diffusing film 102, the transparent base film 105 wound in a roll shape is continuously fed, and the translucent fine particles 106a are dispersed. It includes a step of applying a resin liquid and drying it as necessary, a step of curing a layer made of 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.

  First, the transparent base film 105 is continuously unwound by the unwinding device 301. Next, a resin liquid in which translucent fine particles 106 a are dispersed is applied onto the unwound transparent base film 105 using a coating device 302 and a backup roll 303 facing the coating device 302. Next, when a solvent is contained in the resin liquid, the resin liquid is dried by passing it through a dryer 304. Next, the transparent base film 105 provided with a layer made of a resin liquid is a mirror surface metal roll or an embossing metal roll 305 between the nip roll 306 and the layer made of the resin liquid is a mirror surface metal roll. Or it winds so that it may contact | adhere with the metal roll 305 for embossing. 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 made of the resin liquid. Next, in a state where the transparent base film 105 is wound around the mirror surface metal roll or the embossing metal roll 305, the ultraviolet light is irradiated from the ultraviolet irradiation device 308 through the transparent base film 105, thereby removing from the resin liquid. The resulting layer is cured. Since the irradiated surface becomes hot due to the 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 about 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 produced as described above is taken up by the take-up device 309. At this time, for the purpose of protecting the light diffusing layer 106, it is wound up with a surface protective film made of polyethylene terephthalate, polyethylene, or the like attached to the surface of the light diffusing layer 106 through an adhesive layer having removability. Also good.

  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. Further, instead of performing ultraviolet irradiation in a state of being wound around a mirror surface metal roll or an embossing metal roll 305, a transparent base film 105 on which a layer made of an uncured resin liquid is formed is used as a mirror surface metal roll. Or after peeling from the metal roll 305 for embossing, you may harden by irradiating an ultraviolet-ray.

  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. As an adhesive, an adhesive composed of an active energy ray or a thermosetting resin composition such as a curable resin composition containing an epoxy resin, or an aqueous adhesive containing a polyvinyl alcohol resin or a urethane resin as an adhesive component Etc. can be preferably used. Especially, since the improvement of production efficiency which does not require a drying process etc. can be aimed at and favorable adhesive strength is obtained, the adhesive agent which consists of curable resin composition containing an epoxy resin is used more preferable.

  Bonding of the light diffusion film 102 and the polarizing film 101 using an adhesive made of a curable resin composition containing an epoxy resin is performed by coating the adhesive on the bonding surface of the light diffusion film 102 or the polarizing film 101. And after laminating | stacking both films through an uncured adhesive bond layer, it can carry out by hardening | curing an uncured adhesive bond layer by irradiating an active energy ray or heating. 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, and more preferably 0.5 to 5 μm.

(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 resin film made of 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 is used. be able to. The thickness of the transparent resin film 107 is, for example, 10 to 500 μm, and preferably 20 to 300 μm.

  As the surface treatment film 103, for example, the surface treatment layer 108 is an antiglare layer having surface irregularities in which irregular reflection on the surface is used to reduce or prevent reflection on the display screen (that is, the optical treatment described above). (Anti-glare treatment) is an anti-glare film, and the surface treatment layer 108 is an anti-reflection layer that reduces or prevents reflection on the display screen by reducing or preventing reflection of external light incident on the display screen. An antireflection film can be mentioned (that is, the optical treatment is an antireflection treatment).

  As the antiglare film, for example, after the ultraviolet curable resin composition containing or not containing fine particles is coated on the transparent resin film 107, the formed ultraviolet curable resin layer has a predetermined uneven surface shape. An ultraviolet curable resin composition containing fine particles on the transparent resin film 107, or an antiglare layer provided with predetermined surface irregularities by curing the ultraviolet curable resin layer while pressing the uneven surface of the mold. After the coating, a UV curable resin layer is cured without using a mold, and thus an antiglare layer having predetermined surface irregularities by fine particles can be used. A commercially available anti-glare film can also be used as the anti-glare film.

As the antireflection film, for example, a film having a low refractive index layer composed of a material lower than the refractive index of the light diffusion layer 106 as an antireflection layer, or a material higher than the refractive index of the light diffusion layer 106 is used. Examples thereof include a layer having a laminated structure of a high refractive index layer and a low refractive index layer made of a material lower than the refractive index of the high refractive index layer as an antireflection layer. 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, etc. It can contain a low refractive index material and a binder resin. The binder resin forming material may be a conventionally known material, such as polysiloxane resin, hydrolyzate of silicon alkoxide, light or thermosetting multi-branched compound (dendrimer, hyperbranched polymer, etc.), other light or thermosetting resin. Can be used. One or more of other layers such as a hard coat layer and an antistatic layer may be interposed between the transparent resin film 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.

  In the light diffusing polarizing plate of the present invention, the surface treatment film 103 is usually a surface opposite to the surface treatment layer 108 of the transparent resin film 107 (a surface on which the surface treatment film 103 is not subjected to optical treatment). Thus, it is bonded to the light diffusion layer 106 of the light diffusion film 102 via the pressure-sensitive adhesive layer 104.

(Adhesive layer)
The pressure-sensitive adhesive layer 104 is made of a pressure-sensitive adhesive layer having a storage elastic modulus at 25 ° C. of less than 1.0 × 10 ⁶ Pa. By bonding the surface treatment film 103 to the light diffusion layer 106 through the pressure-sensitive adhesive layer exhibiting a storage elastic modulus within such a range, bubbles between the surface irregularities of the light diffusion layer 106 and the pressure-sensitive adhesive layer 104 are obtained. Occurrence of color loss due to mixing can be effectively suppressed. When the storage elastic modulus at 25 ° C. is 1.0 × 10 ⁶ Pa or more, bubbles enter the surface irregularities of the light diffusion layer 106 and the pressure-sensitive adhesive layer 104 at the time of bonding, and the bubbles are applied to the liquid crystal display device. The dot-shaped color omission corresponding to. From the viewpoint of more effectively suppressing the mixing of bubbles during bonding, the storage elastic modulus of the pressure-sensitive adhesive layer 104 at 25 ° C. is preferably 5.0 × 10 ⁵ Pa or less.

Moreover, it is preferable that the storage elastic modulus in 25 degreeC of the adhesive layer 104 is 1.0 * 10 < ⁵ > Pa or more. Thereby, the favorable hardness (pencil hardness) of the outermost surface (surface of the surface treatment 108) of a light diffusable polarizing plate is securable. When the storage elastic modulus is less than 1.0 × 10 ⁵ Pa, the outermost surface tends to be dented and sufficient hardness may not be maintained.

  Storage elastic modulus (dynamic elastic modulus) is a commonly used term for viscoelasticity measurement, and is generated by applying strain or stress that changes (vibrates) over time to a sample. This value is obtained by measuring the mechanical properties of the sample by measuring the stress or strain (dynamic viscoelasticity measurement). The strain is in phase with the stress and the phase is 90 degrees out of phase with the stress. The elastic modulus is in the same phase as the vibration stress when divided into two component waves. The storage elastic modulus can be measured using a commercially available viscoelasticity measuring device, for example, a dynamic viscoelasticity measuring device (Dynamic Analyzer RDA II: manufactured by REOMETRIC Co., Ltd.) as shown in the examples described later. For the temperature control of the viscoelasticity measuring apparatus, various known temperature control devices such as a circulating thermostat, an electric heater, a Peltier element, and the like are used, and thereby the temperature at the time of measurement can be set.

  Examples of the pressure-sensitive adhesive that forms the pressure-sensitive adhesive layer exhibiting the storage elastic modulus include pressure-sensitive adhesives based on acrylic polymers, silicone polymers, polyesters, polyurethanes, polyethers, and the like. Among these, an acrylic pressure-sensitive adhesive having an acrylic polymer as a base polymer is preferably used from the viewpoints of transparency, adhesive strength, reliability, reworkability, and the like. In the acrylic polymer, a functional group comprising an alkyl ester of acrylic acid having an alkyl group having 20 or less carbon atoms such as a methyl group, an ethyl group, or a butyl group, and (meth) acrylic acid or hydroxyethyl (meth) acrylate. An acrylic copolymer having a weight average molecular weight of 100,000 or more obtained by copolymerizing a group-containing acrylic monomer with a glass transition temperature of preferably 25 ° C. or lower, more preferably 0 ° C. or lower is a base polymer Useful as.

  The acrylic base polymer is not particularly limited, but (meth) such as butyl (meth) acrylate, ethyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, etc. An acrylic ester base polymer and a copolymer base polymer using two or more of these (meth) acrylic esters are preferably used. In addition, polar monomers may be copolymerized with these base polymers. Examples of polar monomers include (meth) acrylic acid, 2-hydroxypropyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, (meth) acrylamide, and 2-N, N-dimethylaminoethyl (meth). Mention may be made of monomers having polar functional groups such as carboxyl groups, hydroxyl groups, amide groups, amino groups, epoxy groups, such as acrylates and glycidyl (meth) acrylates.

  These acrylic polymers can be used alone as a pressure-sensitive adhesive, but a crosslinking agent is usually added to the pressure-sensitive adhesive. As the crosslinking agent, a divalent or polyvalent metal ion that forms a carboxylic acid metal salt with a carboxyl group, a polyamine compound that forms an amide bond with a carboxyl group, Examples include polyepoxy compounds or polyol compounds that form an ester bond with a carboxyl group, and polyisocyanate compounds that form a urea bond with a carboxyl group.

  For example, the type and amount of the cross-linking agent are appropriately selected to lower the cross-linking density of the base polymer, the type of monomer forming the base polymer is appropriately selected to reduce the acid value, Alternatively, the storage modulus of the pressure-sensitive adhesive layer can be lowered to the above range by lowering the degree of polymerization of the base polymer and relatively increasing the content of the low molecular weight component. On the other hand, by adding an oligomer (such as urethane acrylate oligomer) to the pressure-sensitive adhesive composition or by irradiating and curing such an oligomer-containing pressure-sensitive adhesive composition with energy rays, the storage elastic modulus is increased. In order to adjust the storage elastic modulus, such a method may be used in combination.

  In addition to the above base polymer and cross-linking agent, the pressure-sensitive adhesive includes, for example, natural products or synthetic materials in order to adjust the pressure-sensitive adhesive force, cohesive force, viscosity, elastic modulus, glass transition temperature, etc. Appropriate additives such as resins, tackifier resins, antioxidants, ultraviolet absorbers, dyes, pigments, antifoaming agents, corrosion inhibitors, and photopolymerization initiators can also be blended. Examples of the ultraviolet absorber include salicylic acid ester compounds, benzophenone compounds, benzotriazole compounds, cyanoacrylate compounds, and nickel complex compounds.

  The pressure-sensitive adhesive layer can be provided by a method in which the above-mentioned pressure-sensitive adhesive is, for example, an organic solvent solution, which is applied to the transparent resin film 107 by a die coater or a gravure coater and dried. The sheet-like pressure-sensitive adhesive formed on the plastic film (referred to as a separate film) to which the above has been applied can also be provided by a method of transferring 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, preferably in the range of 5 to 30 μm.

  The bonding surface of the transparent resin film 107 and / or the light diffusion layer 106 may be subjected to an easy adhesion process such as a corona discharge process or a primer process (formation of a primer layer) prior to bonding with an adhesive. .

(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 having low birefringence and excellent 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 resins such as terephthalate; polyimide resins; polysulfone resins; polyethersulfone resins; polystyrene resins; polyvinyl alcohol resins; polyvinyl chloride resins; polyolefin resins or polyamide resins It is done. Among these, a triacetyl cellulose film and a norbornene-based thermoplastic resin film are 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 particularly limited, but from the viewpoint of reducing the thickness of the polarizing plate, etc. 500 micrometers or less are preferable, More preferably, it is the range of 5-300 micrometers, More preferably, it is the range of 5-150 micrometers.

  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.

  Instead of the protective film 109, an optical compensation film such as a retardation film (retardation plate) or the like may be bonded to the polarizing film 101.

  The light diffusing polarizing plate having the above configuration is typically a glass substrate of a liquid crystal cell through an adhesive layer or the like so that the surface treatment film 103 is on the viewing side when applied to a liquid crystal display device. Is attached to the liquid crystal display device.

<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. A liquid crystal display device 400 of FIG. 3 is a normally white mode TN liquid crystal display device, and includes a backlight device 402, a light diffusion means 403, a backlight-side polarizing plate 404, and a pair of transparent substrates 411a and 411b. A liquid crystal cell 401 in which a liquid crystal layer 412 is provided, and a light diffusing polarizing plate 405 according to the present invention which is a viewing side polarizing plate are arranged in this order. 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 rectangular parallelepiped case 421 having an upper surface opening and a plurality of cold cathode tubes 422 as linear light sources arranged in parallel in the case 421. The light diffusion means 403 is provided on the light diffusion plate 403a disposed on the backlight device 402 and on the front side of the light diffusion plate 403a (between the light diffusion plate 403a and the backlight side polarizing plate 404). And an optical deflection plate (prism sheet) 403b.

  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 with respect to the normal direction is given. The directivity with respect to the normal direction is set higher than that of the conventional apparatus. 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.

  Thus, in the liquid crystal display device of the present invention, the directivity in the normal direction of the light incident on the liquid crystal cell 401 in the light diffusing unit 403 is made higher than that in the conventional case, that is, the incident light to the liquid crystal cell 401 is conventionally transmitted. The light is further condensed 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.

Hereinafter, the constituent members constituting the liquid crystal display device of the present invention will be described in more detail.
(Liquid crystal cell)
The liquid crystal cell 401 includes a pair of transparent substrates 411a and 411b arranged to face each other with a predetermined distance by a spacer, and a liquid crystal layer 412 formed by sealing liquid crystal between the pair of transparent substrates 411a and 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.

(Backlight device)
The backlight device 402 includes a rectangular parallelepiped case 421 having an upper surface opening, and a plurality of cold cathode tubes 422 as linear light sources arranged in parallel in the case 421. The case 421 is formed from a resin material or a metal material, and at least the inner peripheral surface of the case 421 may be white or silver from the viewpoint of reflecting the light emitted from the cold cathode tube 422 on the inner peripheral surface of the case 421. desirable. 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.

[Light diffusion means]
As shown in FIG. 4, the light diffusing unit 403 includes a light diffusing plate 403a disposed on the backlight device 402, and a front side of the light diffusing plate 403a (the light diffusing plate 403a and the backlight side polarizing plate 404 And a light deflector 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, polyvinyl chloride 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, and polyimide resins can be used.

  Further, 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 made of a material having a refractive index different from that of the material to be the base material 430. For example, it is different from the material to be the base material 430. Organic fine particles made of various acrylic resins, melamine resins, polyethylene resins, polystyrene resins, organic silicone resins, acrylic-styrene copolymer resins, and the like, and calcium carbonate, silica, aluminum oxide, barium carbonate, barium sulfate, titanium oxide, Examples include inorganic fine particles made of glass. 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.

  On the other hand, the light deflection plate (prism sheet) 403b has a flat surface on the light incident surface side (backlight device 402 side) and a tapered cross section on the light emission surface (surface facing the backlight side polarizing plate 404). A plurality of polygonal prisms, preferably triangular linear prisms 450, are formed in parallel. Examples of the material of the light deflector 403b include polycarbonate resins, ABS resins, methacryl resins, methyl methacrylate-styrene copolymer resins, polystyrene resins, acrylonitrile-styrene copolymer resins, and polyolefin resins such as polyethylene and polypropylene. Examples thereof include resins. 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.

  The light diffusing plate 403a and the light deflecting plate 403b may be formed integrally, 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.

  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.

  Further, as shown in FIG. 6, the light diffusing unit 403 may include two light deflecting plates (prism sheets) arranged on the front side of the light diffusing plate 403a. In this case, referring to FIG. 6, the light deflection plate 403b disposed on the side close to the light diffusion plate 403a has the direction of the ridge line 451 of the linear prism 450 substantially equal to the transmission axis direction of the backlight side polarizing plate 404. The light deflection plate 403b ′ arranged so as to be parallel to each other and disposed on the front side of the light deflection plate 403b has the direction of the ridge line 451 ′ of the linear prism 450 ′ as the transmission axis direction of the light diffusing polarizing plate 405. Are preferably arranged so as to be substantially parallel to each other. With such a configuration, the luminance in the front direction of the liquid crystal display device can be further improved. However, it is arranged so that the direction of the ridge line 451 ′ of the linear prism 450 ′ of the light deflector 403b ′ is substantially parallel to the transmission axis direction of the backlight side polarizing plate 404, and the linear prism 450 of the light deflector 403b. It is also possible to arrange the ridge line 451 so that the direction of the ridge line 451 is substantially parallel to the transmission 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 that the luminance value in the direction inclined by 70 ° from the normal direction of the light incident surface of the liquid crystal cell 401 is the front luminance value, that is, the light incident surface of the liquid crystal cell 401. It is preferable that the luminance value is 20% or less with respect to the luminance value in the normal direction, and the emitted light from the light diffusion means 403 includes non-parallel light. A more preferable light distribution characteristic is to prevent light exceeding 60 ° from the normal line of the light incident surface of the liquid crystal cell 401. Normally, as shown in FIG. 3, the back 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 direction of 70 ° with respect to the normal line of the light incident surface of the liquid crystal cell 401 is For example, as shown in FIG. 7, the luminance value is a normal line to the xy plane when the longitudinal direction of the light diffusing unit 403 is the x direction and the plane parallel to the back 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, 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 this triangle, an equal side and an unequal side can be arbitrary, but an isosceles triangle is preferable when concentrating in the normal direction of the liquid crystal cell 401 (front direction of the liquid crystal display device). 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.

  As shown in FIG. 8, non-parallel light means that light emitted from a circle having a diameter of 1 cm on the emission surface of the light diffusing means 403 is parallel to the emission surface, which is 1 m away from the normal direction of the emission surface. When viewed as a projection image on a simple observation surface, the light has an emission characteristic 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 can be used.

(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 phase difference plate 406 is disposed between the backlight side polarizing plate 404 and the liquid crystal cell 401. This phase difference plate 406 has a substantially zero phase difference in a direction perpendicular to the surface of the liquid crystal cell 401, has no optical effect from the front, and has a phase difference when viewed from an oblique direction. It is expressed and compensates for the phase difference generated in the liquid crystal cell 401. As a result, a wider viewing angle can be obtained, and better display quality and color reproducibility can be obtained. The retardation plate 406 can be disposed between the backlight side polarizing plate 404 and the liquid crystal cell 401, or between the light diffusing polarizing plate 405 and the liquid crystal cell 401, or both. The retardation film 406 can be laminated on the protective film of the backlight-side polarizing plate 404, or can be laminated directly on the polarizing film so as to function as a protective film. The same applies to the light diffusing polarizing plate 405.

  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.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited to these Examples. In the following examples, the haze and surface centerline average roughness Ra of the light diffusing film, the thickness of the light diffusing layer, the weight average particle diameter of the light-transmitting fine particles used in the light diffusing layer, and the storage elasticity of the pressure-sensitive adhesive layer The method for measuring the ratio and the pencil hardness of the surface of the surface-treated film (surface of the surface-treated layer) is as follows.

(A) Haze Using an optically transparent adhesive, measurement was performed using a measurement sample in which a light diffusion film was bonded to a glass substrate on the base film side. For the measurement of the total haze value and the internal haze, a haze transmittance meter (haze meter “HM-150” manufactured by Murakami Color Research Laboratory Co., Ltd.) based on JIS K 7136 was used. Based on the result, the surface haze was calculated from the above formula (3).

(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) Thickness of light diffusing layer 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) 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).

(E) Storage elastic modulus of adhesive layer (25 ° C)
A cylindrical test piece having a diameter of 8 mm and a thickness of 1 mm made of a pressure-sensitive adhesive to be measured is prepared, and a dynamic viscoelasticity measuring device (Dynamic Analyzer RDA II: manufactured by REOMETRIC) is used with a torsional shear method with a frequency of 1 Hz. Measurement was performed under the conditions of an initial strain of 1 N and a temperature of 25 ° C.

(F) Pencil hardness on the surface of the surface-treated film According to JIS K 5600-5-4 (pencil scratch test method), scratch measurement is performed 5 times with a load of 500 g, and the hardest pencil in the case where scratches are not scratched twice or more. The hardness was defined as the hardness of the surface-treated film surface. Pencil hardness is measured before and after the surface treatment film is bonded to the light diffusion film (the surface treatment film in the light diffusing polarizing plate to which the surface treatment film prepared in each example and comparative example is bonded). The hardness of the surface was measured.

[Production of surface-treated film]
(Production Example 1: Production of antiglare film)
The surface of a 200 mm diameter iron roll (STKM13A by JIS) was prepared by applying copper ballad plating. Copper ballad plating consists of a copper plating layer / thin silver plating layer / surface copper plating layer, and the thickness of the entire plating layer was about 200 μm. The copper-plated surface is mirror-polished, and further, zirconia beads TZ-B125 (manufactured by Tosoh Corporation, average particle size: 125 μm) are used 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 shall apply 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 Corp., 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).

  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.

  Next, with respect to 100 parts by weight of the solid content of the ultraviolet curable resin composition, “Lucillin 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.

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. Next, the dried transparent resin film was brought into close contact with the concavo-convex 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. The pencil hardness of the surface of the antiglare layer of the obtained antiglare film was 3H.

(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 by irradiating the transparent resin film after drying with ultraviolet rays at a power of 120 W for 10 seconds from a distance of 20 cm using a metal hydride lamp. The obtained hard coat layer had a thickness of 5 μm and a refractive index of 1.52.

Next, isopropyl alcohol and 0.1N hydrochloric acid were added to tetraethoxysilane and hydrolyzed to obtain a solution containing a tetraethoxysilane polymer composed of an oligomer. 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 was formed was immersed in a 1.5N-NaOH aqueous solution at 50 ° C. for 2 minutes for alkali treatment, washed with water, and then washed with a 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 dryer 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.

  Next, an oligomer is formed 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 the mixture. A solution containing a polymer of an organosilicon 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 comprising a hard coat layer, an antistatic layer and a low refractive index layer on a transparent resin film was produced. The pencil hardness of the surface of the low refractive index layer of the obtained antireflection film was 2H.

[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.

  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) as a photopolymerization initiator Manufactured, 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.

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. The light diffusing film A comprising a light diffusing layer and a transparent substrate film is irradiated with light from a high-pressure mercury lamp in an amount of 300 mJ / cm ^{2 in} terms of the amount of h-line conversion to cure the ultraviolet curable resin composition layer. Got.

  Total haze, internal haze, and surface haze of the obtained light diffusion film A were 60.1%, 59.3%, and 0.8%, respectively. Further, the center line average roughness Ra of the surface was 0.31 μm, and the thickness of the light diffusion layer was 10.5 μm.

<Examples 1-3, Comparative 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 diffusion film A is laminated on one surface of a polarizing film obtained by adsorbing and orienting iodine on a uniaxially stretched polyvinyl alcohol resin film, and the protective film is disposed on the other surface. It laminated | stacked through the adhesive bond layer, and was pinched with a pair of nip roll. 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.

  Next, Table 1 shows the antiglare film obtained in Production Example 1 so that the transparent resin film side becomes a bonding surface on the light diffusion layer of the light diffusion film A in the light diffusion polarizing plate. A light diffusable polarizing plate was obtained by pasting through a sheet-like pressure-sensitive adhesive having a storage elastic modulus and a thickness and subjected to an antiglare treatment. The bubble mixing to the surface unevenness | corrugation of the light-diffusion layer at the time of bonding was observed visually. The evaluation results are also shown in Table 1. Table 1 also shows the pencil hardness of the antiglare layer surface of the obtained light diffusing polarizing plate subjected to the antiglare treatment.

<Examples 4 to 6, Comparative Example 2>
A light diffusing polarizing plate that has been subjected to antireflection treatment in the same manner as in Examples 1 to 3 and Comparative Example 1 except that the antireflection film obtained in Production Example 2 was used instead of the antiglare film. Obtained. Table 1 shows the evaluation results of bubble contamination. In addition, Table 1 shows the pencil hardness of the surface of the low refractive index layer of the obtained light diffusing polarizing plate subjected to the antireflection treatment.

  DESCRIPTION OF SYMBOLS 100,405 Light diffusable polarizing plate, 101 Polarizing film, 102 Light diffusing film, 103 Surface treatment film, 104 Adhesive layer, 105 Transparent base film, 106 Light diffusing layer, 106a Translucent fine particle, 106b Translucent resin , 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 UV irradiation device, 309 winding device, 400, 400 ′ liquid crystal display device, 401 liquid crystal cell, 402 backlight device, 403 light diffusion means, 403a light diffusion plate, 403b, 403b ′ light deflection plate, 404 back Light side polarization , 406 retardation 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 ′ linear prism ridge line .

Claims (11)

A polarizing film;
A light diffusion film laminated on the polarizing film;
A surface-treated film that is laminated on the light diffusion film, and is subjected to optical treatment on one surface of the transparent resin film;
With
The light diffusion film has a light diffusion layer having a center line average roughness Ra of 0.1 μm or more and less than 1 μm,
The light diffusion layer of the light diffusion film and the surface treatment film are bonded to each other via an adhesive layer having a storage elastic modulus at 25 ° C. of less than 1.0 × 10 ⁶ Pa. . The light diffusable polarizing plate according to claim 1, wherein the adhesive layer has a storage elastic modulus at 25 ° C. of 1.0 × 10 ⁵ Pa or more.   The light diffusable polarizing plate of Claim 1 or 2 with which the said light-diffusion layer and the surface where the optical treatment of the said surface treatment film is not performed are mutually bonded through the said adhesive layer.   The surface treatment film is an antiglare film in which an antiglare treatment is performed on one surface of a transparent resin film, or an antireflection film in which an antireflection treatment is performed on one surface of a transparent resin film. Item 4. The light diffusing polarizing plate according to any one of Items 1 to 3.   The said light-diffusion film is equipped with a transparent base film and the said light-diffusion layer by which the translucent fine particle was disperse | distributed in the translucent resin laminated | stacked on the said transparent base film. The light diffusable polarizing plate in any one.   The light diffusing polarizing plate according to claim 5, 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.   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 then transferring a mirror surface or an uneven surface of a mold onto the surface of the layer made of the resin liquid. The light diffusing polarizing plate according to claim 5, wherein the light diffusing polarizing plate is formed. 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 7, in this order,
The light diffusing polarizing plate is a liquid crystal display device arranged such that the polarizing film side faces the liquid crystal cell.   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 of Claim 8 containing non-parallel light.   The liquid crystal display device according to claim 8, wherein the light diffusing unit includes a light diffusing plate and a light deflecting plate in this order from the backlight device side.   The liquid crystal display device according to claim 8, 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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