WO2011004906A1 - Liquid crystal display device and light diffusion film - Google Patents

Liquid crystal display device and light diffusion film Download PDF

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Publication number
WO2011004906A1
WO2011004906A1 PCT/JP2010/061855 JP2010061855W WO2011004906A1 WO 2011004906 A1 WO2011004906 A1 WO 2011004906A1 JP 2010061855 W JP2010061855 W JP 2010061855W WO 2011004906 A1 WO2011004906 A1 WO 2011004906A1
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WO
WIPO (PCT)
Prior art keywords
liquid crystal
light
light diffusion
diffusion layer
display device
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PCT/JP2010/061855
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French (fr)
Japanese (ja)
Inventor
羽場康弘
山原基裕
Original Assignee
住友化学株式会社
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Application filed by 住友化学株式会社 filed Critical 住友化学株式会社
Priority to CN201080029994XA priority Critical patent/CN102472912A/en
Publication of WO2011004906A1 publication Critical patent/WO2011004906A1/en

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    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/133504—Diffusing, scattering, diffracting elements
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/02—Diffusing elements; Afocal elements
    • 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
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/133528—Polarisers
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • G02F1/133602—Direct backlight
    • G02F1/133604—Direct backlight with lamps
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • G02F1/133602—Direct backlight
    • G02F1/133606—Direct backlight including a specially adapted diffusing, scattering or light controlling members
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • G02F1/133602—Direct backlight
    • G02F1/133606—Direct backlight including a specially adapted diffusing, scattering or light controlling members
    • G02F1/133607—Direct backlight including a specially adapted diffusing, scattering or light controlling members the light controlling member including light directing or refracting elements, e.g. prisms or lenses

Definitions

  • the present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device having excellent viewing angle characteristics.
  • liquid crystal display devices have been widely used from portable small electronic devices such as cellular phones and PDAs (Personal Digital Assistants) to large electric devices such as personal computers and televisions, and their applications are expanding. Yes.
  • a liquid crystal display device does not emit light. For this reason, in a transmissive liquid crystal display device, a backlight device is provided on the back side of the liquid crystal display element, and the liquid crystal display element controls the transmitted light amount of illumination light from the backlight device for each pixel. An image is displayed.
  • liquid crystal display devices such as a TN (Twisted Nematic) method, an STN (Super Twisted Nematic) method, a VA (Vertical Alignment) method, and an IPS (In-plane Switching) method.
  • TN Transmission Nematic
  • STN Super Twisted Nematic
  • VA Very Alignment
  • IPS In-plane Switching
  • a narrow viewing angle direction exists due to light leakage due to the liquid crystal molecules having a retardation value, a shift of the axial angle of the polarizing plate when it is oblique, and the like.
  • a method for expanding the viewing angle a method of optical compensation to a liquid crystal cell or a polarizing plate using a retardation plate is widely adopted (for example, JPH04-229828-A and JPH04-258923-A).
  • a liquid crystal cell is illuminated with parallel or substantially parallel light source light, and the transmitted light of the liquid crystal cell is transmitted by a light diffusion layer having high haze.
  • Methods for diffusing are known (e.g. JPS 58-169132-A, JPS 60-202425-A and JUS 62-110977-A).
  • the light diffusion layer used in these techniques include a concave lens and a transparent base material having irregularities on the surface.
  • the liquid crystal display device has large irregularities on the outermost surface, which is outside the environment where the display device is placed. Reflecting the light, the screen became whitish and the display quality was not sufficient.
  • An object of the present invention is to provide a liquid crystal display device capable of realizing a display with a wide viewing angle and high color reproducibility even in the presence of external light from the environment.
  • Another object of the present invention is to provide a liquid crystal display device capable of expanding the viewing angle without using a retardation plate, that is, without increasing the number of components.
  • the present invention includes the following.
  • a liquid crystal cell in which a liquid crystal layer is provided between a pair of transparent substrates;
  • a backlight device provided on the back side of the liquid crystal cell;
  • a first light diffusion layer having a light diffusion function and / or a light deflection function disposed between the backlight device and the liquid crystal cell;
  • a first polarizing plate disposed between the first light diffusion layer and the liquid crystal cell;
  • a second light diffusion layer disposed on the front side of the liquid crystal cell;
  • a second polarizing plate disposed between the liquid crystal cell and the second light diffusion layer,
  • the second light diffusion layer has a normal direction relative to the intensity of the laser light incident in the normal direction of the second light diffusion layer when a laser beam having a wavelength of 543.5 nm is incident from the normal direction on the back side.
  • a light diffusion characteristic in which the relative intensity of laser light emitted in a direction inclined by 40 ° is 0.0002% to 0.001%;
  • the liquid crystal display device whose external haze of
  • the side (light emitting side) that becomes the display screen of the liquid crystal display device is referred to as “front side”, and the opposite side (light incident side) is referred to as “back side”.
  • liquid crystal display device according to any one of [1] to [4], wherein the liquid crystal cell is any one of a TN liquid crystal cell, an IPS liquid crystal cell, and a VA liquid crystal cell.
  • the combination of the second light diffusion layer and the second support film is composed of a light diffusion film in which a light diffusion layer is formed directly on one surface of the transparent base film or via an adhesive layer.
  • the liquid crystal cell and the first polarizing plate back side of the liquid crystal cell
  • the liquid crystal cell and the second polarizing plate It is preferable to further dispose a retardation plate on the front side of the liquid crystal cell.
  • the retardation plate may not be provided from the viewpoint of reducing the number of parts, improving the assembly of the apparatus and increasing the productivity.
  • the liquid crystal cell may be a TN liquid crystal and may not include a retardation plate.
  • liquid crystal display device of the present invention a wide viewing angle, high display quality, and excellent color reproducibility can be obtained. Further, viewing angle characteristics that do not hinder actual use can be obtained without using a retardation plate.
  • liquid crystal display device according to the present invention will be described with reference to the drawings, but the present invention is not limited to these embodiments.
  • FIG. 1 is a schematic diagram showing an embodiment of a liquid crystal display device according to the present invention.
  • the liquid crystal display device of FIG. 1 is a normally white mode TN liquid crystal display device, and includes a liquid crystal cell 1 in which a liquid crystal layer 12 is provided between a pair of transparent substrates 11a and 11b, and a back surface of the liquid crystal cell 1.
  • a direct-type backlight device 2 provided with a plurality of cold-cathode tubes 21 provided in parallel at predetermined intervals is provided.
  • a first light diffusion layer 3 and a first polarizing plate 4 are arranged in this order from the backlight device side, and on the front side surface of the liquid crystal cell 1 from the liquid crystal cell 1 side.
  • the 2nd polarizing plate 6 and the 2nd light-diffusion layer 5 are arrange
  • the first light diffusing layer 3 includes a light diffusing plate 31 having a light diffusing function and prism sheets (light deflecting structure plates) 32 a and 32 b provided on the front side surface of the light diffusing plate 31 and having a light deflecting function. Is done.
  • the light emitted from the backlight device 2 is diffused by the light diffusion plate 31 of the first light diffusion layer 3, and then the light incident surface of the liquid crystal cell 1 by the prism sheet 32.
  • 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 first polarizing plate 4 and enters the liquid crystal cell 1.
  • the light incident on the liquid crystal cell 1 is emitted from the liquid crystal cell 1 with its polarization plane controlled for each pixel by the orientation of the liquid crystal layer 12 controlled by the electric field.
  • the light emitted from the liquid crystal cell 1 is imaged and diffused by the second polarizing plate 6 and the second light diffusion layer 5.
  • the directivity in the normal direction of the light incident on the liquid crystal cell 1 in the first light diffusion layer 3 is higher than that in the conventional case, that is, the incident light on the liquid crystal cell 1.
  • the light emitted from the liquid crystal cell 1 is diffused by the second light diffusion layer 5.
  • a wide viewing angle and excellent color reproducibility can be obtained as compared with the conventional apparatus.
  • a liquid crystal is sealed between a pair of transparent substrates 11a and 11b arranged to face each other at a predetermined distance by a spacer (not shown), and the pair of transparent substrates 11a and 11b.
  • the liquid crystal layer 12 is provided.
  • a transparent electrode and an alignment film are laminated on each of the pair of transparent substrates 11a and 11b, 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 1 is the TN method, but a display method such as an IPS method or a VA method may be adopted.
  • the backlight device 2 used in the present invention is not limited to the direct type shown in FIG. 1, but is a side-ride 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 light source itself. Conventionally known ones such as a planar light source type can be used.
  • the first light diffusion layer 3 includes a light diffusion plate 31 and prism sheets 32a and 32b. Specifically, as illustrated in FIG. 2, the first light diffusion layer 3 may have a configuration in which a prism sheet 32 is provided on the front side of the light diffusion plate 31.
  • the light diffusing plate 31 has a configuration in which a diffusing agent 312 is dispersed in a base material 311.
  • polycarbonate methacrylic resin, methyl methacrylate-styrene copolymer resin, acrylonitrile-styrene copolymer resin, methacrylic acid-styrene copolymer resin, polystyrene, polyvinyl chloride, polypropylene, Polyolefins such as polymethylpentene, cyclic polyolefins, polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, polyamide resins, polyarylate, polyimide, and the like can be used.
  • the diffusing agent 312 dispersed in the base material 311 is fine particles made of a substance having a refractive index different from that of the material of the base material 311.
  • a kind of acrylic resin different from the material of the base material 311 Organic fine particles such as melamine resin, polyethylene, polystyrene, organic silicone resin, acrylic-styrene copolymer, and inorganic fine particles such as calcium carbonate, silica, aluminum oxide, barium carbonate, barium sulfate, titanium oxide, glass, etc.
  • Organic polymer balloons and glass hollow beads can also be used as the diffusing agent 312.
  • the average particle size of the diffusing agent 312 is preferably in the range of 0.5 ⁇ m to 30 ⁇ m.
  • the shape of the diffusing agent 312 may be not only spherical but also flat, plate-like, and needle-like.
  • the prism sheet 32 has a flat surface on the back side (light incident surface side) and a prism surface in which V-shaped linear grooves 321 are arranged in parallel on the front side (light emission surface side).
  • the material of the prism sheet 32 include polycarbonate resin, ABS resin, methacrylic resin, methyl methacrylate-styrene copolymer resin, polystyrene resin, acrylonitrile-styrene copolymer resin, polyolefin resin such as polyethylene / polypropylene, or Examples include cured products of ionizing radiation curable resins such as ultraviolet curable resins and electron beam curable resins.
  • the prism sheet 32 can be manufactured by a known method such as a profile extrusion method, a press molding method, an injection molding method, a roll transfer method, a laser ablation method, a mechanical cutting method, a mechanical grinding method, or a photopolymer process method. Each of these methods may be used alone, or two or more methods may be combined. Further, a light diffusing agent may be dispersed in the prism sheet 32.
  • the thickness of the prism sheet 32 is usually 0.1 to 15 mm, preferably 0.5 to 10 mm.
  • the light diffusing plate 31 and the prism sheet 32 may be formed integrally, or may be formed separately and then joined. Moreover, when producing and joining as a different body, you may make it contact between the light-diffusion plate 31 and the prism sheet 32 via an air layer.
  • a diffusing agent 312 is dispersed in a prism sheet 32 having a light deflection function, and the prism sheet 32 is further provided with a light diffusing function.
  • the light diffusing plate 31 may be omitted.
  • the light distribution characteristic of the light that has passed through the first light diffusion layer 3 is such that the luminance in a direction inclined by 70 ° from the normal direction is 20% or less with respect to the luminance in the normal direction, and from the first light diffusion layer.
  • the emitted light preferably includes non-parallel light.
  • a more preferable light distribution characteristic is an alignment characteristic in which there is no light in a direction inclined at an angle exceeding 60 ° from the normal direction.
  • the non-parallel light is parallel to the light emitting surface 71, as shown in FIG. 4, in which the light emitted from the circle 72 having a diameter of 1 cm on the light emitting surface 71 is separated by 1 m in the normal direction of the light emitting surface 71.
  • the light When viewed as a projected image 74 on a particular observation surface 73, the light has such emission characteristics that the minimum half-value width 75 of the in-plane luminance distribution of the projected image 74 is 30 cm or more. Note that the minimum half-value width here is the minimum value of the half-value width in all directions of the in-plane luminance distribution.
  • the shape of the prism portion 322 having a triangular cross section formed between the V-shaped linear grooves 321 of the prism sheet 32 may be adjusted.
  • the apex angle ⁇ (shown in FIGS. 2 and 3) of the triangle which is the cross section of the prism portion 322 is preferably in the range of 60 to 120 °.
  • each side of this triangle may be either an equal side or an unequal side, and when concentrating in the front direction (normal direction) of the liquid crystal cell 1, the front side (light emission side) It is preferable that the two sides are equal isosceles triangles.
  • a plurality of prism portions 322 having such a triangular cross section are arranged so that the bases opposite to the apex angle ⁇ of the triangle are adjacent to each other, and the ridge lines (or the plurality of V-shaped portions) of the plurality of prism portions 322 are arranged.
  • the linear grooves 321) are preferably arranged so as to be substantially parallel to each other. In this case, as long as the light collecting ability is not significantly reduced, each vertex of the triangular shape of the prism portion 322 may have a curved shape or the like.
  • the distance d between the vertices (shown in FIGS. 2 and 3) is usually in the range of 10 ⁇ m to 500 ⁇ m, and preferably in the range of 30 ⁇ m to 200 ⁇ m.
  • the first polarizing plate 4 used in the present invention one obtained by bonding a support film on both sides of a polarizer is usually used.
  • polarizers are those obtained by adsorbing and orienting dichroic dyes or iodine on polarizer substrates such as polyvinyl alcohol resins, polyvinyl acetate resins, ethylene / vinyl acetate (EVA) resins, polyamide resins, and polyester resins.
  • EVA ethylene / vinyl acetate
  • polyamide resins polyamide resins
  • polyester resins polyester resins.
  • a molecularly oriented polyvinyl alcohol film a polyvinyl alcohol / polyvinylene copolymer containing oriented molecular chains of a dichroic dehydrated product of polyvinyl alcohol (polyvinylene).
  • a polarizer substrate made of polyvinyl alcohol resin obtained by adsorbing and orienting a dichroic dye or iodine is preferably used as the polarizer.
  • the thickness of the polarizer is not particularly limited, but in general, it is preferably 100 ⁇ m or less, more preferably in the range of 10 to 50 ⁇ m, still more preferably in the range of 25 to 35 ⁇ m for the purpose of reducing the thickness of the polarizing plate.
  • a film made of a polymer having low birefringence, excellent transparency, mechanical strength, thermal stability, moisture shielding property and the like is preferable.
  • films are cellulose acetate resins such as TAC (triacetyl cellulose), acrylic resins, fluorine resins such as tetrafluoroethylene / hexafluoropropylene copolymers, polycarbonate resins, polyethylene terephthalate.
  • a triacetyl cellulose film or a norbornene-based thermoplastic resin film whose surface is saponified with an alkali or the like can be preferably used from the viewpoints of polarization characteristics and durability.
  • the norbornene-based thermoplastic resin film is particularly suitable because the film becomes a good barrier from heat and wet heat, so that the durability of the polarizing plate 4 is greatly improved and the dimensional stability is greatly improved because of its low moisture absorption rate.
  • a conventionally known method such as a casting method, a calendar method, or an extrusion method can be used.
  • the thickness of the support film is not limited, but is usually preferably 500 ⁇ m or less, more preferably in the range of 5 to 300 ⁇ m, and still more preferably in the range of 5 to 150 ⁇ m, from the viewpoint of reducing the thickness of the polarizing plate 4.
  • the second polarizing plate 6 is paired with the first polarizing plate 4 disposed on the back side of the liquid crystal cell 1, and those exemplified for the first polarizing plate 4 can also be suitably used here.
  • the second polarizing plate 6 is usually arranged so that the deflection surface thereof is orthogonal to the deflection surface of the first polarizing plate 4 or in parallel.
  • the first polarizing plate and the second polarizing plate may be installed so that the deflection surfaces thereof are perpendicular to each other. What is necessary is just to install so that the polarizing surface of 2 polarizing plates may become parallel.
  • FIG. 5 shows a schematic diagram of the second light diffusion layer 5 and the second polarizing plate 6 arranged in the liquid crystal display device of FIG.
  • FIGS. 5A and 5B illustrate various forms of the second light diffusion layer 5.
  • the second polarizing plate 6 includes a polarizer 60, a first support film 61 disposed on the liquid crystal cell side of the polarizer 60, and the second light diffusion layer 5 side of the polarizer. It is comprised from the 2nd support film 62 arrange
  • the polarizer 60 is the same as the polarizer used for the second polarizing plate.
  • the 1st support film 61 and the 2nd support film 62 are the same as the support film used for the above-mentioned 2nd polarizing plate.
  • the second light diffusing layer 5 is obtained by applying a resin composition in which minute translucent fine particles 52 are dispersed on the second support film 62 of the second polarizing plate 6, and making the surface flat and curing.
  • the translucent resin layer 51 in which translucent fine particles 52 are dispersed is formed on the second polarizing plate 6 as the second light diffusion layer 5.
  • the dispersion of the translucent fine particles 52 in the resin composition is preferably isotropic dispersion.
  • a resin composition in which minute translucent fine particles 52 are dispersed is applied on the second support film 62 of the second polarizing plate 6 and cured.
  • a translucent resin layer 51 having irregularities on the surface where the translucent fine particles 52 are dispersed is formed on the second polarizing plate 6.
  • a hard coat layer 53 having a flat surface is formed by applying a resin composition similar to that of the light transmissive resin layer 51 containing no light transmissive fine particles thereon and then curing the surface with a flat surface.
  • the 2nd polarizing plate 6 is the same as that of Fig.5 (a).
  • the second light diffusing layer 5 having such a configuration is adapted to the intensity of the laser light incident in the normal direction of the second light diffusing layer when laser light having a wavelength of 543.5 nm is incident from the normal direction on the back side.
  • the light diffusion characteristic is such that the relative intensity of the laser light emitted in a direction inclined by 40 ° from the normal direction is 0.0002% to 0.001%. Furthermore, it is preferable that the angle (emitted angle) with respect to the normal direction where the relative intensity of the laser beam is 0.0008% or less is 40 ° or more.
  • the light transmitted from the liquid crystal cell 1 to the front side is scattered forward, and the viewing angle is suppressed while coloring of the image viewed from an oblique direction is suppressed while maintaining the sharpness of the image of the transmitted light in the front direction. Becomes wider.
  • the light-transmitting resin layer 51 in which the light-transmitting fine particles 52 are dispersed is used as the second light diffusion layer 5
  • What is necessary is just to adjust the shape, particle diameter, addition amount of the fine particles 52, the refractive index difference between the translucent fine particles 52 and the translucent resin layer 51, and the like.
  • any resin can be used as long as it is a transparent resin that can be cured by any method. It is preferable to use a product. And the method of hardening
  • the ultraviolet curable resin composition known ones can be used, but considering that the second light diffusion layer is disposed on the outermost side of the liquid crystal display device, the light diffusion layer has sufficient mechanical strength. Therefore, it is preferable that the ultraviolet curable resin composition also has characteristics as a resin composition for hard coat. As such an ultraviolet curable resin composition, an acrylic or epoxy hard coat resin composition is preferably used.
  • a polyfunctional acrylate such as trimethylolpropane triacrylate or pentaerythritol tetraacrylate alone or Mixtures of two or more with photopolymerization initiators such as “Irgacure 907”, “Irgacure 184” (from Ciba Specialty Chemicals), “Lucirin TPO” (from BASF), etc. It can be preferably used.
  • the translucent fine particles 52 are fine particles made of a material having a refractive index different from that of the translucent resin layer 51, and examples thereof include acrylic resin, melamine resin, polyethylene, polystyrene, organic silicone resin, and acrylic-styrene copolymer.
  • Organic fine particles such as calcium carbonate, silica, aluminum oxide, barium carbonate, barium sulfate, titanium oxide, glass and the like, and one of these is used, or two or more are mixed. Can be used. Organic polymer balloons and glass hollow beads can also be used.
  • the average particle diameter of the translucent fine particles 52 is preferably in the range of 1 ⁇ m to 25 ⁇ m.
  • the shape of the translucent fine particles 52 may be any of a spherical shape, a flat shape, a plate shape, a needle shape, and the like, but a spherical shape is particularly desirable.
  • FIG. 6 is a schematic diagram for explaining a method of forming the second light diffusing layer 5 on the second polarizing plate 6 using the light diffusing film 54.
  • the light diffusion film 54 includes a light diffusion layer 54A and a transparent base film 54B.
  • the light diffusion layer 54A is the same as the second light diffusion layer described above.
  • the transparent substrate film 54B is not particularly limited as long as it is a transparent film.
  • the resin used for forming the transparent substrate film 54B include cellulose acetate resins such as TAC (triacetyl cellulose), Examples thereof include acrylic resins, polycarbonate resins, and polyester resins such as polyethylene terephthalate.
  • Method 1 using a light diffusion film As shown in FIG. 6A, the transparent base film 54B side of the light diffusion film 54 is laminated directly or via an adhesive layer on the polarizer 60 (on the side opposite to the first support film 61). In this way, the light diffusion layer 54A and the transparent base film 54B of the light diffusion film 54 are used as the second light diffusion layer 5 and the second support film 62 of the liquid crystal display device, respectively, and the first support film 61, The second polarizing plate 6 in which the polarizer 60 and the second support film 62 are laminated in this order, and the second light diffusion layer 5 directly laminated on the second support film 62 are obtained.
  • the transparent base film 54 ⁇ / b> B side of the light diffusion film 54 is laminated on the second support film of the second polarizing plate 6 directly or via an adhesive layer.
  • an adhesive layer here is comprised from an adhesive or an adhesive agent.
  • the first support film 61, the polarizer 60, and the second support film 62 are laminated in this order, and the second support film 62 is directly or via an adhesive layer.
  • the transparent substrate film 54B is laminated, and the second light diffusion layer 5 laminated directly on the transparent substrate film 54B is obtained.
  • the “normal direction on the back side of the second polarizing plate” refers to the normal direction on the light incident side with respect to the flat surface of the second polarizing plate 6.
  • FIG. 7 schematically shows the incident direction and the emission direction of the laser beam when measuring the relative intensity of the laser beam incident from the normal direction on the back side of the second polarizing plate and emitted to the second light diffusion layer side.
  • FIG. 7 the direction of the angle ⁇ from the normal direction 92 on the second light diffusion layer side with respect to the laser light 93 incident in the normal direction from the back side (the lower side in the figure) of the surface 91 of the second light diffusion layer.
  • the intensity of the laser beam 94 emitted from the laser beam is measured.
  • a value obtained by dividing the measured intensity of the laser beam 94 by the intensity of the incident laser beam 93 is the relative intensity. Note that the laser beam 94, the normal direction 92, and the incident laser beam 93 are all measured on the same plane (plane 95 in FIG. 7).
  • FIG. 8 is an example of a graph in which the relative intensity of laser light emitted from the second light diffusion layer side is plotted against the emission angle ⁇ .
  • the relative intensity has a peak in the outgoing angle of 0 °, that is, the normal direction 92 in FIG. 7, and the relative intensity tends to decrease as the outgoing angle ⁇ increases with respect to the normal direction 92.
  • the relative intensity is 0.0008% or less when the emission angle ⁇ is 41 ° or more.
  • FIG. 9 shows another embodiment of the liquid crystal display device of the present invention.
  • the liquid crystal display device of FIG. 9 is different from the liquid crystal display device of FIG. 1 in that a phase difference plate 8 is disposed between the first polarizing plate 4 and the liquid crystal cell 1.
  • This phase difference plate 8 has substantially zero phase difference in the normal direction of the surface of the liquid crystal cell 1 and has no optical effect on the normal direction (front direction) of the surface of the liquid crystal cell 1.
  • a phase difference appears in a direction oblique to the direction, and an attempt is made to compensate for the phase difference generated in the liquid crystal cell 1 when the liquid crystal display device is viewed obliquely.
  • the retardation plate 8 can be disposed between the first polarizing plate 4 and the liquid crystal cell 1 and between or between the second polarizing plate 6 and the liquid crystal cell 1.
  • phase difference plate 8 examples include those obtained by using a polycarbonate resin or a cyclic olefin polymer resin as a film, further biaxially stretching the film, and those obtained by fixing a molecular arrangement of a liquid crystalline monomer by a photopolymerization reaction. Since the phase difference plate 8 optically compensates for the alignment of the liquid crystal, it is preferable to use one having a refractive index characteristic opposite to that of the liquid crystal alignment.
  • liquid crystal display cell of TN mode for example, “WV film” (manufactured by Fuji Film Co., Ltd.)
  • liquid crystal display cell of STN mode for example, “LC film” (manufactured by Nippon Oil Corporation)
  • LC film manufactured by Nippon Oil Corporation
  • IPS mode liquid crystal cell for example, biaxial retardation film
  • VA mode liquid crystal cell for example, retardation plate combining A-plate and C-plate, biaxial retardation film, ⁇ cell mode
  • OV WV film manufactured by Fuji Film Co., Ltd.
  • crosslinked siloxane-based resin particles (“Trefill DY33-719” manufactured by Toray Dow Corning Silicone Co., Ltd., refractive index of 1.42, Together with a weight average particle diameter of 2 ⁇ m), the mixture was melt kneaded by a first extruder and supplied to a feed block.
  • the addition amount of the crosslinked siloxane-based resin particles the total light transmittance Tt of the diffusion plate was adjusted, and a light diffusion plate having a total light transmittance Tt of 65% was produced.
  • the resin supplied from the first extruder to the feed block becomes an intermediate layer (base layer), and the resin supplied from the second extruder to the feed block becomes a surface layer (both sides).
  • the laminate is made of three layers having a thickness of 2 mm (intermediate layer 1.90 mm, surface layer 0.05 mm ⁇ 2).
  • the total light transmittance Tt was measured using a haze / transmittance meter (HR-100, manufactured by Murakami Color Research Laboratory Co., Ltd.) in accordance with JIS K 7361.
  • a styrene resin (refractive index: 1.59) was press-molded to produce a 1 mm thick flat plate. Further, as shown in FIG. 2, a prism sheet having prism portions 322 having an isosceles triangle cross section in which the apex angle is ⁇ and the distance d between vertices is 50 ⁇ m, and V-shaped linear grooves 321 are arranged in parallel. Using a metal mold having a shape corresponding to 32, the styrene resin plate was re-press molded to produce a prism sheet.
  • the apex angle ⁇ has a luminance in a direction inclined by 70 ° with respect to the normal line direction when the prism sheet is incorporated as a member of the first light diffusion layer of the liquid crystal display device of an embodiment to be described later.
  • the brightness was adjusted to 0%, 10%, and 20% of the luminance in the line direction.
  • the light diffusing plate 31 and the prism sheets 32a and 32b are arranged in the arrangement shown in FIG.
  • the layers were laminated as follows. At this time, the V-shaped linear groove of one prism sheet is arranged so that the direction of the V-shaped linear groove is substantially parallel to the cold cathode tube 21 of the backlight device 2, and the V-shaped linear groove of the other prism film is arranged.
  • the prism sheets 32a and 32b were laminated so that the direction was orthogonal to the direction of the V-shaped linear groove of the former prism sheet.
  • Pentaerythritol triacrylate 60 parts by mass
  • polyfunctional urethanized acrylate reaction product of hexamethylene diisocyanate and pentaerythritol triacrylate, 40 parts by mass
  • the refractive index of the cured product after removing propylene glycol monomethyl ether from the composition and curing with ultraviolet rays was 1.53.
  • polystyrene particles having a weight average particle diameter of 12.0 ⁇ m (SBX-12 manufactured by Sekisui Plastics Co., Ltd.) are used as translucent fine particles.
  • 30 parts by mass 5 parts by mass of “Lucirin TPO” (BASF Corp., chemical name: 2,4,6-trimethylbenzoyldiphenylphosphine oxide), which is a photopolymerization initiator, is added to a solid content ratio of 60% by mass.
  • a coating solution was prepared by diluting with propylene glycol monomethyl ether.
  • This coating solution was applied onto a flat triacetyl cellulose (TAC) film (second polarizer polarizing film 62 in the second polarizing plate) having a thickness of 80 ⁇ m and dried for 1 minute in a dryer set at 80 ° C. I let you.
  • TAC triacetyl cellulose
  • the TAC film on which the coating solution is dried and the ultraviolet curable resin composition layer is formed is a rubber roll so that the ultraviolet curable resin composition layer is on the mold side on the mirror surface of the mold prepared in (1) above. Press to make contact.
  • ⁇ Production Example 2 Second light diffusion layer in the same manner as in Production Example 1 except that 40 parts by mass of polystyrene-based particles (SBX-6 manufactured by Sekisui Plastics Co., Ltd.) having a weight average particle size of 6.0 ⁇ m were used as the light-transmitting fine particles. Got. At this time, the thickness of the translucent resin layer 51 in which the translucent fine particles 52 were dispersed was 15.5 ⁇ m.
  • the UV curable resin composition layer is irradiated with light from a high pressure mercury lamp having an intensity of 20 mW / cm 2 from the UV curable resin side so as to be 300 mJ / cm 2 in terms of h-ray conversion amount without being pressed against the mirror surface of the mold.
  • a second light diffusion layer was obtained in the same manner as in Production Example 1 except that was cured. At this time, the thickness of the translucent resin layer 51 in which the translucent fine particles 52 were dispersed was 27.2 ⁇ m.
  • the second light diffusion layer was formed in the same manner as in Production Example 5 except that 40 parts by mass of polystyrene-based particles having a weight average particle size of 6.0 ⁇ m (SBX-6 manufactured by Sekisui Plastics Co., Ltd.) were used as the light-transmitting fine particles. Obtained. At this time, the thickness of the translucent resin layer 51 in which the translucent fine particles 52 were dispersed was 16.1 ⁇ m.
  • the TAC film side laminated on the second light diffusion layer is bonded to the glass substrate using an optically transparent adhesive so that the second light diffusion layer becomes the surface. In that state, the entire haze was measured by irradiating light from the glass substrate side.
  • a glass substrate and a TAC film do not influence the measurement of each haze value, and a measured value here is equivalent to the haze value of a 2nd light-diffusion layer.
  • the measurement of the internal haze was performed in the same manner as the measurement of the total haze by sticking a triacetyl cellulose film having a haze of almost 0 to the film surface with glycerin to eliminate the influence of the outside of the film.
  • the external haze was determined from the measured values of the total haze and internal haze according to the following formula.
  • External haze (%) Total haze (%)-Internal haze (%) ⁇ Measurement of laser light intensity at each emission angle>
  • the second light diffusion layer obtained in Production Examples 1 to 6 was bonded to a glass substrate, and from a He-Ne laser having a wavelength of 543.5 nm in the normal direction of the second light diffusion layer from the glass substrate side.
  • the light transmitting resin layer in which the light transmitting fine particles are dispersed among the layers constituting the second light diffusion layer is irradiated at a predetermined angle of 0 ° to 90 ° with respect to the normal direction of the glass substrate surface.
  • the intensity of the laser beam emitted at an angle (exit angle) was measured.
  • “3292 03 optical power sensor” and “3292 optical power meter” manufactured by Yokogawa Electric Corporation were used.
  • the emission angle (°) and normal line where the intensity ratio (relative intensity) of the laser beam emitted at a predetermined emission angle to the intensity of the laser beam applied to the second light diffusion layer is 0.0008% or less.
  • Table 1 shows the relative intensity (%) emitted in a direction inclined by 40 ° from the direction.
  • a light source for irradiating a He—Ne laser was disposed at a position of 430 mm from the glass substrate.
  • the power sensor which is a light receiver, was placed at a position 280 mm from the emission point of the laser beam, and the power sensor was moved to the predetermined angle to measure the intensity of the emitted laser beam. Further, the intensity of the laser light irradiated to the second light diffusion layer, that is, the intensity of the laser light irradiated from the light source is determined from the light source without installing a glass substrate on which the second light diffusion layer is bonded. It was determined by measuring the intensity of light directly incident on the power sensor. In addition, the said intensity
  • positioning the said power sensor in the position of 710 mm ( 430mm + 280mm) from the said light source.
  • Example 1 As the liquid crystal display device, the luminance in the direction inclined by 70 ° from the normal direction is the luminance in the normal direction on the front side of the backlight device of the 32-inch liquid crystal television (LC-32D10-B) manufactured by Sharp Corporation in VA mode. A liquid crystal display device provided with the first light diffusion layer of 10% was used. Next, the polarizing plates on both sides and the retardation plate in the liquid crystal cell of the liquid crystal display device are peeled off, and an iodine-based normal polarizing plate (TRW842AP7) manufactured by Sumitomo Chemical Co., Ltd.
  • TRW842AP7 iodine-based normal polarizing plate manufactured by Sumitomo Chemical Co., Ltd.
  • the iodine-based normal polarization obtained by bonding the second light diffusion layer with the TAC film (the polarizer support film in the second polarizing plate) obtained in Production Example 1 to the front side.
  • Example 2 As the first light diffusion layer, the first light diffusion layer (Example 2) in which the luminance in the direction inclined by 70 ° from the normal direction is 0% of the luminance in the normal direction, and the first diffusion layer which is 20% A liquid crystal display device was produced in the same manner as in Example 1 except that (Example 3) was used.
  • Example 4 A liquid crystal display device was produced in the same manner as in Example 1 except that the second light diffusion layer obtained in Production Example 2 was used as the second light diffusion layer.
  • Example 1 A liquid crystal display device was produced in the same manner as in Example 1 except that the second light diffusion layer obtained in Production Example 3 was used as the second light diffusion layer.
  • Example 2 A liquid crystal display device was produced in the same manner as in Example 1 except that the second light diffusion layer obtained in Production Example 4 was used as the second light diffusion layer.
  • the viewing angle with respect to the front direction (normal direction) of the liquid crystal screen is between 0 ° (front) and 60 °. No abnormality was observed in gradation inversion, gradation collapse, color tone, white floating in black display, and luminance change, and all were good. In the evaluation in the bright room, the display quality was good as in the evaluation in the dark room.
  • the liquid crystal display device of Comparative Example 1 had a low luminance when viewed from an oblique direction and an insufficient viewing angle. Further, the liquid crystal display device of Comparative Example 2 had low luminance when viewed from the front, and display quality was insufficient. Further, the liquid crystal display devices of Comparative Examples 3 and 4 had sufficient display quality in the dark room, but the screen became whitish in the bright room, and the display quality was insufficient.
  • Example 5 As a liquid crystal display device, a liquid crystal display device was produced in the same manner as in Example 1 except that a 26-inch liquid crystal television (TL2686TW) manufactured by TECO in TN mode was used, and visual evaluation was performed in a dark room and a bright room. In both the dark room and the bright room, when the viewing angle is between 0 ° (front) and 60 °, there are no abnormalities in gradation inversion, gradation collapse, color tone, white floating in black display, and luminance change. The display quality was good.
  • TECO 26-inch liquid crystal television
  • Example 6 A liquid crystal display device was produced in the same manner as in Example 1 except that a 32-inch liquid crystal television (VIERA TH-32LZ85) manufactured by Panasonic Corporation in IPS mode was used as the liquid crystal display device, and visual evaluation was performed in a dark room and a bright room. In both the dark room and the bright room, when the viewing angle is between 0 ° (front) and 60 °, there are no abnormalities in gradation inversion, gradation collapse, color tone, white floating in black display, and luminance change. The display quality was good.
  • VIPERA TH-32LZ85 32-inch liquid crystal television manufactured by Panasonic Corporation in IPS mode

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Abstract

Disclosed is a liquid crystal display device which comprises: a liquid crystal cell that is obtained by arranging a liquid crystal layer between a pair of transparent substrates; a backlight unit that is arranged on the back surface side of the liquid crystal cell; a first light diffusion layer that is arranged between the backlight unit and the liquid crystal cell and has a light diffusing function and/or a light deflecting function; a first polarizing plate that is arranged between the first light diffusion layer and the liquid crystal cell; a second light diffusion layer that is arranged on the front surface side of the liquid crystal cell; and a second polarizing plate that is arranged between the liquid crystal cell and the second light diffusion layer. The second light diffusion layer has such light diffusion characteristics that when laser light having a wavelength of 549 nm is incident thereupon from the back surface side in the normal line direction, the relative intensity of the laser light outgoing therefrom in the direction that is inclined to the normal line direction at 40˚ with respect to the intensity of the laser light incident thereupon in the normal line direction is 0.0002-0.001%. The external haze of the second light diffusion layer is less than 1.0%. The liquid crystal display device is capable of achieving display with wide viewing angle and high color reproduction even when there is outside light from the environment.

Description

液晶表示装置および光拡散フィルムLiquid crystal display device and light diffusion film
　本発明は液晶表示装置に関し、より詳細には、視野角特性に優れた液晶表示装置に関するものである。 The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device having excellent viewing angle characteristics.
　近年、液晶表示装置は、携帯電話機やＰＤＡ（Ｐｅｒｓｏｎａｌ　Ｄｉｇｉｔａｌ　Ａｓｓｉｓｔａｎｔ）等の携帯用小型電子機器から、パーソナルコンピュータやテレビなどの大型電気機器に至るまで広く使用されており、その用途は益々拡大している。 In recent years, liquid crystal display devices have been widely used from portable small electronic devices such as cellular phones and PDAs (Personal Digital Assistants) to large electric devices such as personal computers and televisions, and their applications are expanding. Yes.
　液晶表示装置は、ＣＲＴやＰＤＰ（プラズマディスプレイパネル）などの自発光型の表示装置とは異なり、表示素子自体は発光しない。このため、透過型の液晶表示装置では、液晶表示素子の背面側にバックライト装置が設けられており、このバックライト装置からの照明光の透過光量を液晶表示素子が画素ごとに制御することによって画像の表示が行われる。 Unlike a self-luminous display device such as a CRT or PDP (plasma display panel), a liquid crystal display device does not emit light. For this reason, in a transmissive liquid crystal display device, a backlight device is provided on the back side of the liquid crystal display element, and the liquid crystal display element controls the transmitted light amount of illumination light from the backlight device for each pixel. An image is displayed.
　液晶表示装置には、ＴＮ（Ｔｗｉｓｔｅｄ　Ｎｅｍａｔｉｃ）方式、ＳＴＮ（Ｓｕｐｅｒ　Ｔｗｉｓｔｅｄ　Ｎｅｍａｔｉｃ）方式、ＶＡ（Ｖｅｒｔｉｃａｌ　Ａｌｉｇｎｍｅｎｔ）方式、ＩＰＳ（Ｉｎ−ｐｌａｎｅ　Ｓｗｉｔｃｈｉｎｇ）方式などのさまざまな方式があるが、これらの方式には、液晶分子が位相差値を持つことによる光漏れや、偏光板における斜視時の軸角度のずれなどに起因して、それぞれに視野角の狭い方向（方位角）が存在する。 There are various types of liquid crystal display devices such as a TN (Twisted Nematic) method, an STN (Super Twisted Nematic) method, a VA (Vertical Alignment) method, and an IPS (In-plane Switching) method. A narrow viewing angle direction (azimuth angle) exists due to light leakage due to the liquid crystal molecules having a retardation value, a shift of the axial angle of the polarizing plate when it is oblique, and the like.
　そこで、視野角を拡大する方法として、位相差板による、液晶セルや偏光板への光学補償という方法が広く採用されている（例えば、ＪＰＨ０４−２２９８２８−ＡおよびＪＰＨ０４−２５８９２３−Ａ）。 Therefore, as a method for expanding the viewing angle, a method of optical compensation to a liquid crystal cell or a polarizing plate using a retardation plate is widely adopted (for example, JPH04-229828-A and JPH04-258923-A).
　一方、液晶表示装置において、位相差板を用いずに広い視野角を得る方法として、平行ないし略平行の光源光で液晶セルを照明し、液晶セルの透過光を高いヘイズを有する光拡散層によって拡散する方法が知られている（たとえばＪＰＳ５８−１６９１３２−Ａ、ＪＰＳ６０−２０２４２５−Ａ及びＪＵＳ６２−１１０９７７−Ａ）。 On the other hand, in a liquid crystal display device, as a method of obtaining a wide viewing angle without using a retardation plate, a liquid crystal cell is illuminated with parallel or substantially parallel light source light, and the transmitted light of the liquid crystal cell is transmitted by a light diffusion layer having high haze. Methods for diffusing are known (e.g. JPS 58-169132-A, JPS 60-202425-A and JUS 62-110977-A).
　これらの技術で用いられる光拡散層として、具体的には、凹レンズや、表面に凹凸を有する透明基材が記載されている。 Specific examples of the light diffusion layer used in these techniques include a concave lens and a transparent base material having irregularities on the surface.
　しかしながら、例えば、表面に凹凸を有する透明基材を用いて高いヘイズを有する光拡散層を形成した場合、液晶表示装置の最表面には大きな凹凸を有することとなり、表示装置のおかれる環境の外光を反射して画面が白っぽくなり、表示品位は十分ではなかった。 However, for example, when a light diffusing layer having high haze is formed using a transparent substrate having irregularities on the surface, the liquid crystal display device has large irregularities on the outermost surface, which is outside the environment where the display device is placed. Reflecting the light, the screen became whitish and the display quality was not sufficient.
　本発明は、環境からの外光の存在下でも、広視野角で色再現性の高い表示を実現できる液晶表示装置を提供することを目的とする。 An object of the present invention is to provide a liquid crystal display device capable of realizing a display with a wide viewing angle and high color reproducibility even in the presence of external light from the environment.
　また、本発明の目的は、位相差板を用いることなく、すなわち部品点数を増やすことなく視野角の拡大が図れる液晶表示装置を提供することにある。 Another object of the present invention is to provide a liquid crystal display device capable of expanding the viewing angle without using a retardation plate, that is, without increasing the number of components.
　本発明は、以下のものを含む。
［１］　一対の透明基板の間に液晶層が設けられてなる液晶セルと、
　液晶セルの背面側に設けられたバックライト装置と、
　上記バックライト装置と上記液晶セルとの間に配置された光拡散機能および／または光偏向機能を有する第１光拡散層と、
　上記第１光拡散層と上記液晶セルとの間に配置された第１偏光板と、
　上記液晶セルの前面側に配置された第２光拡散層と、
　上記液晶セルと上記第２光拡散層との間に配置された第２偏光板とを備え、
　上記第２光拡散層は、波長５４３．５ｎｍのレーザ光を背面側の法線方向から入射したときに、第２光拡散層の法線方向に入射するレーザ光の強度に対する、法線方向から４０°傾いた方向に出射するレーザ光の相対強度が０．０００２％~０．００１％である光拡散特性を有し、
　上記第２光拡散層の外部ヘイズが１．０％未満である液晶表示装置。 The present invention includes the following.
[1] A liquid crystal cell in which a liquid crystal layer is provided between a pair of transparent substrates;
A backlight device provided on the back side of the liquid crystal cell;
A first light diffusion layer having a light diffusion function and / or a light deflection function disposed between the backlight device and the liquid crystal cell;
A first polarizing plate disposed between the first light diffusion layer and the liquid crystal cell;
A second light diffusion layer disposed on the front side of the liquid crystal cell;
A second polarizing plate disposed between the liquid crystal cell and the second light diffusion layer,
The second light diffusion layer has a normal direction relative to the intensity of the laser light incident in the normal direction of the second light diffusion layer when a laser beam having a wavelength of 543.5 nm is incident from the normal direction on the back side. A light diffusion characteristic in which the relative intensity of laser light emitted in a direction inclined by 40 ° is 0.0002% to 0.001%;
The liquid crystal display device whose external haze of the said 2nd light-diffusion layer is less than 1.0%.
　なお、本明細書においては、液晶表示装置の表示画面となる側（光出射側）を「前面側」と称し、それとは反対側（光入射側）を「背面側」と称するものとする。 In the present specification, the side (light emitting side) that becomes the display screen of the liquid crystal display device is referred to as “front side”, and the opposite side (light incident side) is referred to as “back side”.
［２］　上記第２光拡散層の内部ヘイズが２０％以上７０％未満である［１］に記載の液晶表示装置。 [2] The liquid crystal display device according to [1], wherein an internal haze of the second light diffusion layer is 20% or more and less than 70%.
［３］　上記第１光拡散層からの出射光は、法線方向から７０°傾いた方向の輝度が法線方向の輝度に対して２０％以下である配光特性を有し、且つ、非平行光を含む、［１］または［２］に記載の液晶表示装置。 [3] The light emitted from the first light diffusion layer has a light distribution characteristic in which the luminance in a direction inclined by 70 ° from the normal direction is 20% or less with respect to the luminance in the normal direction, and The liquid crystal display device according to [1] or [2], which includes parallel light.
［４］　上記第１光拡散層は、上記光拡散機能を奏する光拡散板と、上記光偏向機能を奏する光偏向構造板とを有し、上記光拡散板の前面側に上記光偏向構造板が設けられた、［１］~［３］のいずれかに記載の液晶表示装置。 [4] The first light diffusing layer includes a light diffusing plate having the light diffusing function and a light deflecting structural plate having the light deflecting function, and the light deflecting structural plate on the front side of the light diffusing plate. The liquid crystal display device according to any one of [1] to [3].
［５］　上記液晶セルが、ＴＮ方式液晶セル、ＩＰＳ方式液晶セル及びＶＡ方式液晶セルのいずれかである［１］~［４］のいずれかに記載の液晶表示装置。 [5] The liquid crystal display device according to any one of [1] to [4], wherein the liquid crystal cell is any one of a TN liquid crystal cell, an IPS liquid crystal cell, and a VA liquid crystal cell.
［６］　上記第２偏光板が、偏光子と、該偏光子と液晶セルの間に配置される第１支持フィルムと、該偏光子と上記第２光拡散層の間に配置される第２支持フィルムとを有する［１］~［５］のいずれかに記載の液晶表示装置。 [6] The second polarizing plate includes a polarizer, a first support film disposed between the polarizer and the liquid crystal cell, and a second disposed between the polarizer and the second light diffusion layer. The liquid crystal display device according to any one of [1] to [5], comprising a support film.
［７］　前記第２光拡散層が、前記第２支持フィルムに直接積層されている［６］に記載の液晶表示装置。 [7] The liquid crystal display device according to [6], wherein the second light diffusion layer is directly laminated on the second support film.
［８］　前記第２光拡散層の背面側の面が透明基材フィルムに直接貼合され、且つ該透明基材フィルムの第２光拡散層とは反対の面が前記第２支持フィルムに直接または接着層を介して貼合されている［６］に記載の液晶表示装置。 [8] The surface on the back side of the second light diffusion layer is directly bonded to the transparent base film, and the surface opposite to the second light diffusion layer of the transparent base film is directly on the second support film. Or the liquid crystal display device as described in [6] bonded through the contact bonding layer.
［９］　前記第２光拡散層と前記第２支持フィルムとの組み合わせが、透明基材フィルムの一方の面に直接または接着層を介して光拡散層が形成されている光拡散フィルムからなる、［７］に記載の液晶表示装置。 [9] The combination of the second light diffusion layer and the second support film is composed of a light diffusion film in which a light diffusion layer is formed directly on one surface of the transparent base film or via an adhesive layer. The liquid crystal display device according to [7].
　また、視野角特性および色再現性のさらなる向上の観点からは、上記液晶セルと第１偏光板との間（液晶セルの背面側）および／または上記液晶セルと第２偏光板との間（液晶セルの前面側）に位相差板をさらに配置するのが好ましい。一方、部品点数を少なくして、装置の組み立て性を向上させ生産性を上げる観点から、位相差板を具備しないようにしてもよい。また、上記液晶セルとしてＴＮ方式液晶とし、且つ、位相差板を具備しないようにしてもよい。 Further, from the viewpoint of further improving viewing angle characteristics and color reproducibility, between the liquid crystal cell and the first polarizing plate (back side of the liquid crystal cell) and / or between the liquid crystal cell and the second polarizing plate ( It is preferable to further dispose a retardation plate on the front side of the liquid crystal cell. On the other hand, the retardation plate may not be provided from the viewpoint of reducing the number of parts, improving the assembly of the apparatus and increasing the productivity. The liquid crystal cell may be a TN liquid crystal and may not include a retardation plate.
［１０］　透明基材フィルムの一方の面に直接または接着層を介して光拡散層が形成されている光拡散フィルムであって、該光拡散層は、波長５４３．５ｎｍのレーザ光を背面側の法線方向から入射したときに、該光拡散層の法線方向に入射するレーザ光の強度に対する、法線方向から４０°傾いた方向に出射するレーザ光の相対強度が０．０００２％~０．００１％である光拡散特性を有し、該光拡散層の外部ヘイズが１．０％未満である光拡散フィルム。 [10] A light diffusing film in which a light diffusing layer is formed directly or via an adhesive layer on one surface of a transparent substrate film, and the light diffusing layer transmits laser light having a wavelength of 543.5 nm on the back side. The relative intensity of the laser light emitted in a direction inclined by 40 ° from the normal direction with respect to the intensity of the laser light incident in the normal direction of the light diffusion layer is 0.0002% to A light diffusing film having a light diffusing property of 0.001% and an external haze of the light diffusing layer being less than 1.0%.
［１１］　［６］に記載の液晶表示装置に使用される［１０］に記載の光拡散フィルムであって、上記光拡散層および上記透明基材フィルムが、それぞれ、上記液晶表示装置の第２光拡散層および第２支持フィルムとして使用される光拡散フィルム。 [11] The light diffusing film according to [10] used in the liquid crystal display device according to [6], wherein the light diffusing layer and the transparent base film are each a second of the liquid crystal display device. A light diffusion film used as a light diffusion layer and a second support film.
［１２］　［６］に記載の液晶表示装置に使用される［１０］に記載の光拡散フィルムであって、上記透明基材フィルムが、上記液晶表示装置の第２偏光板の第２支持フィルム側に直接または接着層を介して貼合される光拡散フィルム。 [12] The light diffusing film according to [10] used in the liquid crystal display device according to [6], wherein the transparent base film is a second support film of the second polarizing plate of the liquid crystal display device. A light diffusion film bonded to the side directly or via an adhesive layer.
　本発明の液晶表示装置では、広視野角、高表示品位および優れた色再現性が得られる。また、位相差板を用いなくても実使用上支障のない視野角特性が得られる。 In the liquid crystal display device of the present invention, a wide viewing angle, high display quality, and excellent color reproducibility can be obtained. Further, viewing angle characteristics that do not hinder actual use can be obtained without using a retardation plate.
本発明に係る液晶表示装置の一例を示す概説図である。It is a schematic diagram which shows an example of the liquid crystal display device which concerns on this invention. 第１光拡散層の一例を示す概説図である。It is a schematic diagram which shows an example of a 1st light-diffusion layer. 第１光拡散層の他の例を示す概説図である。It is an outline figure showing other examples of the 1st light diffusion layer. 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. （ａ）、（ｂ）は第２光拡散層および第２偏光板の構成例を示す概説図である。(A), (b) is a schematic diagram which shows the structural example of a 2nd light-diffusion layer and a 2nd polarizing plate. （ａ）、（ｂ）は、光拡散フィルムを用いて第２光拡散層を形成する方法を説明するための概説図である。(A), (b) is a schematic diagram for demonstrating the method of forming a 2nd light-diffusion layer using a light-diffusion film. 第２光拡散層におけるレーザ光の入射方向と出射方向とを模式的に表した図である。It is the figure which represented typically the incident direction and emitting direction of the laser beam in a 2nd light-diffusion layer. 第２光拡散層から出射するレーザ光の相対強度を、出射角に対してプロットしたグラフの一例である。It is an example of the graph which plotted the relative intensity | strength of the laser beam radiate | emitted from a 2nd light-diffusion layer with respect to the outgoing angle. 本発明に係る液晶表示装置の他の例を示す概説図である。It is a schematic diagram which shows the other example of the liquid crystal display device which concerns on this invention.
　以下、本発明に係る液晶表示装置について図に基づいて説明するが、本発明はこれらの実施形態に何ら限定されるものではない。 Hereinafter, the liquid crystal display device according to the present invention will be described with reference to the drawings, but the present invention is not limited to these embodiments.
　図１に、本発明に係る液晶表示装置の一実施形態を示す概説図を示す。図１の液晶表示装置はノーマリホワイトモードのＴＮ方式の液晶表示装置であって、一対の透明基板１１ａ，１１ｂの間に液晶層１２が設けられてなる液晶セル１と、液晶セル１の背面側に設けられた、複数本の冷陰極管２１が所定間隔で平行に設置されてなる直下型のバックライト装置２と備える。バックライト装置２と液晶セル１との間には、バックライト装置側から順に第１光拡散層３、第１偏光板４が配置され、液晶セル１の前側面には、液晶セル１側から順に第２偏光板６、第２光拡散層５が配置されている。第１光拡散層３は、光拡散機能を有する光拡散板３１と、光拡散板３１の前側面に設けられた、光偏向機能を奏するプリズムシート（光偏向構造板）３２ａ，３２ｂとから構成される。 FIG. 1 is a schematic diagram showing an embodiment of a liquid crystal display device according to the present invention. The liquid crystal display device of FIG. 1 is a normally white mode TN liquid crystal display device, and includes a liquid crystal cell 1 in which a liquid crystal layer 12 is provided between a pair of transparent substrates 11a and 11b, and a back surface of the liquid crystal cell 1. A direct-type backlight device 2 provided with a plurality of cold-cathode tubes 21 provided in parallel at predetermined intervals is provided. Between the backlight device 2 and the liquid crystal cell 1, a first light diffusion layer 3 and a first polarizing plate 4 are arranged in this order from the backlight device side, and on the front side surface of the liquid crystal cell 1 from the liquid crystal cell 1 side. The 2nd polarizing plate 6 and the 2nd light-diffusion layer 5 are arrange | positioned in order. The first light diffusing layer 3 includes a light diffusing plate 31 having a light diffusing function and prism sheets (light deflecting structure plates) 32 a and 32 b provided on the front side surface of the light diffusing plate 31 and having a light deflecting function. Is done.
　このような構成の液晶表示装置において、バックライト装置２から放射された光は、第１光拡散層３の光拡散板３１によって拡散された後、プリズムシート３２によって液晶セル１の光入射面の法線方向に対する所定の指向性が付与される。この法線方向に対する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、第１偏光板４によって偏光とされて液晶セル１に入射する。液晶セル１に入射した光は、電場によって制御された液晶層１２の配向によって画素ごとに偏光面が制御されて液晶セル１から出射する。そして、液晶セル１から出射した光は、第２偏光板６、第２光拡散層５によって画像化されると共に拡散される。 In the liquid crystal display device having such a configuration, the light emitted from the backlight device 2 is diffused by the light diffusion plate 31 of the first light diffusion layer 3, and then the light incident surface of the liquid crystal cell 1 by the prism sheet 32. 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 first polarizing plate 4 and enters the liquid crystal cell 1. The light incident on the liquid crystal cell 1 is emitted from the liquid crystal cell 1 with its polarization plane controlled for each pixel by the orientation of the liquid crystal layer 12 controlled by the electric field. The light emitted from the liquid crystal cell 1 is imaged and diffused by the second polarizing plate 6 and the second light diffusion layer 5.
　このように、本発明の液晶表示装置では、第１光拡散層３における、液晶セル１に入射する光の法線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１への入射光を従来よりも集光させたものとするとともに、液晶セル１からの出射光を第２光拡散層５によって拡散させる。これによって、従来の装置に比べて広視野角および優れた色再現性が得られるようになる。 As described above, 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 1 in the first light diffusion layer 3 is higher than that in the conventional case, that is, the incident light on the liquid crystal cell 1. The light emitted from the liquid crystal cell 1 is diffused by the second light diffusion layer 5. As a result, a wide viewing angle and excellent color reproducibility can be obtained as compared with the conventional apparatus.
　以下、本発明の液晶表示装置の各部材について説明する。まず、本発明で使用する液晶セル１は、不図示のスペーサにより所定距離を隔てて対向配置された一対の透明基板１１ａ，１１ｂと、この一対の透明基板１１ａ，１１ｂの間に液晶を封入されてなる液晶層１２とを備える。図１では示していないが、一対の透明基板１１ａ，１１ｂ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１の表示方式はここではＴＮ方式であるが、ＩＰＳ方式、ＶＡ方式などの表示方式を採用しても構わない。 Hereinafter, each member of the liquid crystal display device of the present invention will be described. First, in the liquid crystal cell 1 used in the present invention, a liquid crystal is sealed between a pair of transparent substrates 11a and 11b arranged to face each other at a predetermined distance by a spacer (not shown), and the pair of transparent substrates 11a and 11b. The liquid crystal layer 12 is provided. Although not shown in FIG. 1, a transparent electrode and an alignment film are laminated on each of the pair of transparent substrates 11a and 11b, and the liquid crystal is aligned by applying a voltage based on display data between the transparent electrodes. To do. Here, the display method of the liquid crystal cell 1 is the TN method, but a display method such as an IPS method or a VA method may be adopted.
　本発明で使用するバックライト装置２は、図１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ド型、あるいは光源自体が平面状の平面光源型など従来公知のものを使用できる。 The backlight device 2 used in the present invention is not limited to the direct type shown in FIG. 1, but is a side-ride 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 light source itself. Conventionally known ones such as a planar light source type can be used.
　第１光拡散層３は、光拡散板３１とプリズムシート３２ａ，３２ｂとを有する。具体的には、図２に例示されるように、第１光拡散層３は光拡散板３１の前面側にプリズムシート３２が設けられた構成が挙げられる。ここで、光拡散板３１は基材３１１に拡散剤３１２が分散された構成となっている。 The first light diffusion layer 3 includes a light diffusion plate 31 and prism sheets 32a and 32b. Specifically, as illustrated in FIG. 2, the first light diffusion layer 3 may have a configuration in which a prism sheet 32 is provided on the front side of the light diffusion plate 31. Here, the light diffusing plate 31 has a configuration in which a diffusing agent 312 is dispersed in a base material 311.
　基材３１１を構成する樹脂としては、ポリカーボネート、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、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、ポリ塩化ビニル、ポリプロピレン、ポリメチルペンテン等のポリオレフィン、環状ポリオレフィン、ポリエチレンテレフタレート、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、ポリイミド等が使用できる。 As the resin constituting the substrate 311, polycarbonate, methacrylic resin, methyl methacrylate-styrene copolymer resin, acrylonitrile-styrene copolymer resin, methacrylic acid-styrene copolymer resin, polystyrene, polyvinyl chloride, polypropylene, Polyolefins such as polymethylpentene, cyclic polyolefins, polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, polyamide resins, polyarylate, polyimide, and the like can be used.
　また、基材３１１に分散させる拡散剤３１２は、基材３１１となる材料と屈折率が異なる物質からなる微粒子であって、具体例としては、基材３１１の材料とは異なる種類のアクリル樹脂、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の有機微粒子、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、ガラス等の無機微粒子等が挙げられ、これらの中の１種を使用するか、または２種類以上を混合して使用することができる。また、有機重合体のバルーンやガラス中空ビーズも拡散剤３１２として使用できる。拡散剤３１２の平均粒径は０．５μｍ~３０μｍの範囲が好適である。また、拡散剤３１２の形状としては、球状のみならず偏平状、板状、針状等であってもよい。 Further, the diffusing agent 312 dispersed in the base material 311 is fine particles made of a substance having a refractive index different from that of the material of the base material 311. As a specific example, a kind of acrylic resin different from the material of the base material 311, Organic fine particles such as melamine resin, polyethylene, polystyrene, organic silicone resin, acrylic-styrene copolymer, and inorganic fine particles such as calcium carbonate, silica, aluminum oxide, barium carbonate, barium sulfate, titanium oxide, glass, etc. One of these can be used, or two or more can be mixed and used. Organic polymer balloons and glass hollow beads can also be used as the diffusing agent 312. The average particle size of the diffusing agent 312 is preferably in the range of 0.5 μm to 30 μm. Further, the shape of the diffusing agent 312 may be not only spherical but also flat, plate-like, and needle-like.
　一方、プリズムシート３２は、背面側（光入射面側）が平坦面で、前面側（光出射面側）は、Ｖ字状の直線溝３２１が平行に配列形成されてなるプリズム面となっている。プリズムシート３２の材料としては、例えば、ポリカーボネート樹脂や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・ポリプロピレン等のポリオレフィン樹脂、あるいは、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の硬化物などが挙げられる。プリズムシート３２は、異形押出法、プレス成形法、射出成形法、ロール転写法、レーザブレーション法、機械切削法、機械研削法、フォトポリマープロセス法などの公知の方法で製造することができる。これらの方法は、それぞれ単独で使用されてもよいし、あるいは２種以上の方法を組み合わせてもよい。また、プリズムシート３２に光拡散剤を分散してもよい。プリズムシート３２の厚みは、通常、０．１~１５ｍｍであり、好ましくは０．５~１０ｍｍである。 On the other hand, the prism sheet 32 has a flat surface on the back side (light incident surface side) and a prism surface in which V-shaped linear grooves 321 are arranged in parallel on the front side (light emission surface side). Yes. Examples of the material of the prism sheet 32 include polycarbonate resin, ABS resin, methacrylic resin, methyl methacrylate-styrene copolymer resin, polystyrene resin, acrylonitrile-styrene copolymer resin, polyolefin resin such as polyethylene / polypropylene, or Examples include cured products of ionizing radiation curable resins such as ultraviolet curable resins and electron beam curable resins. The prism sheet 32 can be manufactured by a known method such as a profile extrusion method, a press molding method, an injection molding method, a roll transfer method, a laser ablation method, a mechanical cutting method, a mechanical grinding method, or a photopolymer process method. Each of these methods may be used alone, or two or more methods may be combined. Further, a light diffusing agent may be dispersed in the prism sheet 32. The thickness of the prism sheet 32 is usually 0.1 to 15 mm, preferably 0.5 to 10 mm.
　光拡散板３１とプリズムシート３２とは一体に成形してもよいし、別体で作製した後接合してもよい。また、別体として作製し接合する場合、光拡散板３１とプリズムシート３２との間に空気層を介して接触させてもよい。 The light diffusing plate 31 and the prism sheet 32 may be formed integrally, or may be formed separately and then joined. Moreover, when producing and joining as a different body, you may make it contact between the light-diffusion plate 31 and the prism sheet 32 via an air layer.
　第１光拡散層３の異なる実施態様としては、図３に示すように、光偏向機能を有するプリズムシート３２に拡散剤３１２を分散させて、プリズムシート３２にさらに光拡散機能を付与することにより、光拡散板３１を省略してもよい。 As a different embodiment of the first light diffusing layer 3, as shown in FIG. 3, a diffusing agent 312 is dispersed in a prism sheet 32 having a light deflection function, and the prism sheet 32 is further provided with a light diffusing function. The light diffusing plate 31 may be omitted.
　第１光拡散層３を通過した光の配光特性は、法線方向から７０°傾いた方向の輝度が法線方向の輝度に対して２０％以下であり、且つ、第１光拡散層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、法線方向から６０°を超える角度傾いた方向の光がないような配向特性である。 The light distribution characteristic of the light that has passed through the first light diffusion layer 3 is such that the luminance in a direction inclined by 70 ° from the normal direction is 20% or less with respect to the luminance in the normal direction, and from the first light diffusion layer. The emitted light preferably includes non-parallel light. A more preferable light distribution characteristic is an alignment characteristic in which there is no light in a direction inclined at an angle exceeding 60 ° from the normal direction.
　ここで、非平行光とは、図４に示すように、発光面７１における直径１ｃｍの円７２内から出射された光を、発光面７１の法線方向に１ｍ離れた、発光面７１に平行な観察面７３における投影像７４として観察したとき、その投影像７４の面内輝度分布の最小半値幅７５が３０ｃｍ以上であるような出射特性を有する光である。なお、ここでいう最小半値幅とは、面内輝度分布の全方向における半値幅の最小値である。 Here, the non-parallel light is parallel to the light emitting surface 71, as shown in FIG. 4, in which the light emitted from the circle 72 having a diameter of 1 cm on the light emitting surface 71 is separated by 1 m in the normal direction of the light emitting surface 71. When viewed as a projected image 74 on a particular observation surface 73, the light has such emission characteristics that the minimum half-value width 75 of the in-plane luminance distribution of the projected image 74 is 30 cm or more. Note that the minimum half-value width here is the minimum value of the half-value width in all directions of the in-plane luminance distribution.
　このような配光特性とするためには、例えば、プリズムシート３２のＶ字状の直線溝３２１の間に形成される三角形の断面を有するプリズム部分３２２の形状を調整すればよい。プリズム部分３２２の断面である三角形の頂角θ（図２、３に図示）は、６０~１２０°の範囲が好ましい。また、この三角形は、各辺が等辺、不等辺のいずれのものであってもよく、液晶セル１の正面方向（法線方向）に集光しようとする場合は、前面側（光出射側）の二辺が等しい二等辺三角形であることが好ましい。 In order to obtain such a light distribution characteristic, for example, the shape of the prism portion 322 having a triangular cross section formed between the V-shaped linear grooves 321 of the prism sheet 32 may be adjusted. The apex angle θ (shown in FIGS. 2 and 3) of the triangle which is the cross section of the prism portion 322 is preferably in the range of 60 to 120 °. In addition, each side of this triangle may be either an equal side or an unequal side, and when concentrating in the front direction (normal direction) of the liquid crystal cell 1, the front side (light emission side) It is preferable that the two sides are equal isosceles triangles.
　上記プリズムシート３２は、かかる三角形の断面を有する複数のプリズム部分３２２が、三角形の頂角θに相対する底辺が互いに隣接するように配置され、複数のプリズム部分３２２の稜線（もしくは複数のＶ字状の直線溝３２１）が互いにほぼ平行になるように配列された構造を有することが好ましい。この場合、集光能力が著しく減退しない限り、プリズム部分３２２の断面形状の三角形は、その各頂点が曲線形状等となっていてもよい。
各頂点間の距離ｄ（図２、３に図示）は、通常、１０μｍ~５００μｍの範囲であり、好ましくは、３０μｍ~２００μｍの範囲である。 In the prism sheet 32, a plurality of prism portions 322 having such a triangular cross section are arranged so that the bases opposite to the apex angle θ of the triangle are adjacent to each other, and the ridge lines (or the plurality of V-shaped portions) of the plurality of prism portions 322 are arranged. The linear grooves 321) are preferably arranged so as to be substantially parallel to each other. In this case, as long as the light collecting ability is not significantly reduced, each vertex of the triangular shape of the prism portion 322 may have a curved shape or the like.
The distance d between the vertices (shown in FIGS. 2 and 3) is usually in the range of 10 μm to 500 μm, and preferably in the range of 30 μm to 200 μm.
　本発明で使用する第１偏光板４としては、通常は、偏光子の両面に支持フィルムを貼り合わせたものが使用される。偏光子の例は、ポリビニルアルコール系の樹脂、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、ポリエステル樹脂等の偏光子基板に、二色性染料またはヨウ素を吸着配向させたもの、及び分子的に配向したポリビニルアルコールフィルム中に、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）の配向した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含む。特に、ポリビニルアルコール系樹脂の偏光子基板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子として好適に使用される。偏光子の厚さに特に限定はないが、一般には偏光板の薄型化等を目的に、１００μｍ以下が好ましく、より好ましくは１０~５０μｍの範囲、さらに好ましくは２５~３５μｍの範囲である。 As the first polarizing plate 4 used in the present invention, one obtained by bonding a support film on both sides of a polarizer is usually used. Examples of polarizers are those obtained by adsorbing and orienting dichroic dyes or iodine on polarizer substrates such as polyvinyl alcohol resins, polyvinyl acetate resins, ethylene / vinyl acetate (EVA) resins, polyamide resins, and polyester resins. And in a molecularly oriented polyvinyl alcohol film, a polyvinyl alcohol / polyvinylene copolymer containing oriented molecular chains of a dichroic dehydrated product of polyvinyl alcohol (polyvinylene). In particular, a polarizer substrate made of polyvinyl alcohol resin obtained by adsorbing and orienting a dichroic dye or iodine is preferably used as the polarizer. The thickness of the polarizer is not particularly limited, but in general, it is preferably 100 μm or less, more preferably in the range of 10 to 50 μm, still more preferably in the range of 25 to 35 μm for the purpose of reducing the thickness of the polarizing plate.
　偏光子を支持・保護する支持フィルムとしては、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なるフィルムが好ましい。このようなフィルムの例は、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やアクリル系樹脂、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、ポリオレフィン樹脂もしくはポリアミド系樹脂等の樹脂をフィルム状に成形加工したものを含む。これらの中でも、偏光特性や耐久性などの点から、表面をアルカリなどでケン化処理した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、フィルムが熱や湿熱からの良好なバリアーとなるので偏光板４の耐久性が大幅に向上するとともに、吸湿率が少ないため寸法安定性が大幅に向上し、特に好適に使用できる。フィルム状への成形加工は、キャスティング法、カレンダー法、押出し法の従来公知の方法を用いることができる。支持フィルムの厚さに限定はないが、偏光板４の薄型化等の観点から、通常は、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。 As the support film for supporting and protecting the polarizer, a film made of a polymer having low birefringence, excellent transparency, mechanical strength, thermal stability, moisture shielding property and the like is preferable. Examples of such films are cellulose acetate resins such as TAC (triacetyl cellulose), acrylic resins, fluorine resins such as tetrafluoroethylene / hexafluoropropylene copolymers, polycarbonate resins, polyethylene terephthalate. Polyester resin, polyimide resin, polysulfone resin, polyethersulfone resin, polystyrene resin, polyvinyl alcohol resin, polyvinyl chloride resin, polyolefin resin, polyamide resin, etc. Including Among these, a triacetyl cellulose film or a norbornene-based thermoplastic resin film whose surface is saponified with an alkali or the like can be preferably used from the viewpoints of polarization characteristics and durability. The norbornene-based thermoplastic resin film is particularly suitable because the film becomes a good barrier from heat and wet heat, so that the durability of the polarizing plate 4 is greatly improved and the dimensional stability is greatly improved because of its low moisture absorption rate. Can be used for For forming into a film, a conventionally known method such as a casting method, a calendar method, or an extrusion method can be used. The thickness of the support film is not limited, but is usually preferably 500 μm or less, more preferably in the range of 5 to 300 μm, and still more preferably in the range of 5 to 150 μm, from the viewpoint of reducing the thickness of the polarizing plate 4.
　第２偏光板６は、液晶セル１の背面側に配置された第１偏光板４と対となるものであって、第１偏光板４で例示したものがここでも好適に使用できる。ただし、第２偏光板６は、通常、その偏向面が、第１偏光板４の偏向面と直交するように配置されているか、または、平行となるように配置されている。液晶表示装置をノーマリーホワイトとする場合には、第１偏光板と第２偏光板の偏向面が直行するように設置すればよく、ノーマリーブラックとする場合には、第１偏光板と第２偏光板の偏向面が平行になるように設置すればよい。 The second polarizing plate 6 is paired with the first polarizing plate 4 disposed on the back side of the liquid crystal cell 1, and those exemplified for the first polarizing plate 4 can also be suitably used here. However, the second polarizing plate 6 is usually arranged so that the deflection surface thereof is orthogonal to the deflection surface of the first polarizing plate 4 or in parallel. When the liquid crystal display device is normally white, the first polarizing plate and the second polarizing plate may be installed so that the deflection surfaces thereof are perpendicular to each other. What is necessary is just to install so that the polarizing surface of 2 polarizing plates may become parallel.
　（第２光拡散層の形成）
　図５に、図１の液晶表示装置に配置される第２光拡散層５および第２偏光板６の概説図を示す。図５（ａ）、（ｂ）は、第２光拡散層５の各種の形態を例示している。 (Formation of second light diffusion layer)
FIG. 5 shows a schematic diagram of the second light diffusion layer 5 and the second polarizing plate 6 arranged in the liquid crystal display device of FIG. FIGS. 5A and 5B illustrate various forms of the second light diffusion layer 5.
　図５（ａ）において、第２偏光板６は、偏光子６０と、該偏光子６０の液晶セル側に配置される第１支持フィルム６１と、該偏光子の第２光拡散層５側に配置される第２支持フィルム６２とから構成されている。偏光子６０は、上述の第２偏光板に用いられる偏光子と同様のものである。第１支持フィルム６１および第２支持フィルム６２は、上述の第２偏光板に用いられる支持フィルムと同様のものである。 In FIG. 5A, the second polarizing plate 6 includes a polarizer 60, a first support film 61 disposed on the liquid crystal cell side of the polarizer 60, and the second light diffusion layer 5 side of the polarizer. It is comprised from the 2nd support film 62 arrange | positioned. The polarizer 60 is the same as the polarizer used for the second polarizing plate. The 1st support film 61 and the 2nd support film 62 are the same as the support film used for the above-mentioned 2nd polarizing plate.
　第２光拡散層５は、微小な透光性微粒子５２を分散させた樹脂組成物を、第２偏光板６の第２支持フィルム６２上に塗布し、表面を平坦にして硬化させることにより、透光性微粒子５２が分散された透光性樹脂層５１を第２光拡散層５として第２偏光板６上に形成したものである。この場合、樹脂組成物中の透光性微粒子５２の分散は等方分散であることが好ましい。 The second light diffusing layer 5 is obtained by applying a resin composition in which minute translucent fine particles 52 are dispersed on the second support film 62 of the second polarizing plate 6, and making the surface flat and curing. The translucent resin layer 51 in which translucent fine particles 52 are dispersed is formed on the second polarizing plate 6 as the second light diffusion layer 5. In this case, the dispersion of the translucent fine particles 52 in the resin composition is preferably isotropic dispersion.
　図５（ｂ）の第２光拡散層５では、微小な透光性微粒子５２を分散させた樹脂組成物を、第２偏光板６の第２支持フィルム６２上に塗布し、硬化させることにより、透光性微粒子５２が分散された表面に凹凸を有する透光性樹脂層５１が第２偏光板６上に形成されている。さらに、その上に透光性微粒子を含有しない透光性樹脂層５１と同様の樹脂組成物を塗布した後に、表面を平坦にして硬化させることにより、平坦な表面を有するハードコート層５３が形成されている。第２偏光板６は、図５（ａ）と同様である。 In the second light diffusion layer 5 of FIG. 5B, a resin composition in which minute translucent fine particles 52 are dispersed is applied on the second support film 62 of the second polarizing plate 6 and cured. A translucent resin layer 51 having irregularities on the surface where the translucent fine particles 52 are dispersed is formed on the second polarizing plate 6. Further, a hard coat layer 53 having a flat surface is formed by applying a resin composition similar to that of the light transmissive resin layer 51 containing no light transmissive fine particles thereon and then curing the surface with a flat surface. Has been. The 2nd polarizing plate 6 is the same as that of Fig.5 (a).
　このような構成の第２光拡散層５は、波長５４３．５ｎｍのレーザ光を背面側の法線方向から入射したときに、第２光拡散層の法線方向に入射するレーザ光の強度に対する、法線方向から４０°傾いた方向に出射するレーザ光の相対強度が０．０００２％~０．００１％であるような光拡散特性を有する。さらに、レーザ光の相対強度が０．０００８％以下となる法線方向に対する角度（出射角）が４０°以上であることが好ましい。これにより、液晶セル１から前面側に透過する光が前方散乱され、正面方向の透過光の画像の鮮明性が高く維持されたまま、斜め方向から見た際の画像の着色が抑えられ視野角が広くなる。 The second light diffusing layer 5 having such a configuration is adapted to the intensity of the laser light incident in the normal direction of the second light diffusing layer when laser light having a wavelength of 543.5 nm is incident from the normal direction on the back side. The light diffusion characteristic is such that the relative intensity of the laser light emitted in a direction inclined by 40 ° from the normal direction is 0.0002% to 0.001%. Furthermore, it is preferable that the angle (emitted angle) with respect to the normal direction where the relative intensity of the laser beam is 0.0008% or less is 40 ° or more. Thereby, the light transmitted from the liquid crystal cell 1 to the front side is scattered forward, and the viewing angle is suppressed while coloring of the image viewed from an oblique direction is suppressed while maintaining the sharpness of the image of the transmitted light in the front direction. Becomes wider.
　第２光拡散層５の光拡散特性をこのように制御するには、例えば、第２光拡散層５として透光性微粒子５２が分散された透光性樹脂層５１を用いる場合、透光性微粒子５２の形状・粒径・添加量、そして透光性微粒子５２と透光性樹脂層５１との屈折率差などを調整すればよい。 In order to control the light diffusion characteristics of the second light diffusion layer 5 in this way, for example, when the light-transmitting resin layer 51 in which the light-transmitting fine particles 52 are dispersed is used as the second light diffusion layer 5, What is necessary is just to adjust the shape, particle diameter, addition amount of the fine particles 52, the refractive index difference between the translucent fine particles 52 and the translucent resin layer 51, and the like.
　透光性樹脂層５１の形成に用いられる樹脂としては、何らかの方法で硬化させることのできる透明な樹脂であれば任意に用いることができるが、製造や取り扱いの簡便さから、紫外線硬化性樹脂組成物を用いることが好ましい。そして、該紫外線硬化性樹脂組成物を硬化して透光性樹脂層５１を得る方法が好ましく用いられる。紫外線硬化性樹脂組成物としては、公知のものを用いることができるが、第２光拡散層が液晶表示装置の最も外側に配置されることを考慮すると、該光拡散層は十分な機械的強度を有することが好ましく、そのため、紫外線硬化性樹脂組成物はハードコート用樹脂組成物としての特徴を兼ね備えることが好ましい。このような紫外線硬化性樹脂組成物としては、アクリル系、エポキシ系などのハードコート用樹脂組成物が好ましく用いられ、例えば、トリメチロールプロパントリアクリレート、ペンタエリスリトールテトラアクリレート等の多官能アクリレートの単独または２種以上と、「イルガキュアー　９０７」、「イルガキュアー　１８４」（以上、チバ・スペシャルティー・ケミカルズ社製）、「ルシリン　ＴＰＯ」（ＢＡＳＦ社製）等の光重合開始剤との混合物などを特に好ましく用いることができる。 As the resin used for forming the translucent resin layer 51, any resin can be used as long as it is a transparent resin that can be cured by any method. It is preferable to use a product. And the method of hardening | curing this ultraviolet curable resin composition and obtaining the translucent resin layer 51 is used preferably. As the ultraviolet curable resin composition, known ones can be used, but considering that the second light diffusion layer is disposed on the outermost side of the liquid crystal display device, the light diffusion layer has sufficient mechanical strength. Therefore, it is preferable that the ultraviolet curable resin composition also has characteristics as a resin composition for hard coat. As such an ultraviolet curable resin composition, an acrylic or epoxy hard coat resin composition is preferably used. For example, a polyfunctional acrylate such as trimethylolpropane triacrylate or pentaerythritol tetraacrylate alone or Mixtures of two or more with photopolymerization initiators such as “Irgacure 907”, “Irgacure 184” (from Ciba Specialty Chemicals), “Lucirin TPO” (from BASF), etc. It can be preferably used.
　透光性微粒子５２は、透光性樹脂層５１と屈折率が異なる材質からなる微粒子であって、その例は、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の有機微粒子、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、ガラス等の無機微粒子を含み、これらの中の１種を使用するか、または２種類以上を混合して使用することができる。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５２の平均粒径は１μｍ~２５μｍの範囲が好適である。透光性微粒子５２の形状は、球状、偏平状、板状、針状等いずれであってもよいが、特に球状が望ましい。 The translucent fine particles 52 are fine particles made of a material having a refractive index different from that of the translucent resin layer 51, and examples thereof include acrylic resin, melamine resin, polyethylene, polystyrene, organic silicone resin, and acrylic-styrene copolymer. Organic fine particles such as calcium carbonate, silica, aluminum oxide, barium carbonate, barium sulfate, titanium oxide, glass and the like, and one of these is used, or two or more are mixed. Can be used. Organic polymer balloons and glass hollow beads can also be used. The average particle diameter of the translucent fine particles 52 is preferably in the range of 1 μm to 25 μm. The shape of the translucent fine particles 52 may be any of a spherical shape, a flat shape, a plate shape, a needle shape, and the like, but a spherical shape is particularly desirable.
　（光拡散フィルムを用いた第２光拡散層の形成）
　第２光拡散層５を第２偏光板６上に形成するための別の有利な態様として、光拡散フィルムを用いる方法が挙げられる。図６は、光拡散フィルム５４を用いて第２光拡散層５を第２偏光板６上に形成する方法を説明するための概説図である。光拡散フィルム５４は、光拡散層５４Ａおよび透明基材フィルム５４Ｂからなる。 (Formation of second light diffusion layer using light diffusion film)
Another advantageous embodiment for forming the second light diffusion layer 5 on the second polarizing plate 6 includes a method using a light diffusion film. FIG. 6 is a schematic diagram for explaining a method of forming the second light diffusing layer 5 on the second polarizing plate 6 using the light diffusing film 54. The light diffusion film 54 includes a light diffusion layer 54A and a transparent base film 54B.
　光拡散層５４Ａは、上述の第２光拡散層と同様のものである。また、透明基材フィルム５４Ｂは透明性を有するフィルムであれば特に限定されないが、透明基材フィルム５４Ｂの形成に用いられる樹脂としては、例えば、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やアクリル系樹脂、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等が挙げられる。 The light diffusion layer 54A is the same as the second light diffusion layer described above. The transparent substrate film 54B is not particularly limited as long as it is a transparent film. Examples of the resin used for forming the transparent substrate film 54B include cellulose acetate resins such as TAC (triacetyl cellulose), Examples thereof include acrylic resins, polycarbonate resins, and polyester resins such as polyethylene terephthalate.
　（１）　光拡散フィルムを用いる方法１
　図６（ａ）に示されるように、光拡散フィルム５４の透明基材フィルム５４Ｂ側が、（第１支持フィルム６１と反対側の）偏光子６０上に直接または接着層を介して積層される。このようにして、光拡散フィルム５４の光拡散層５４Ａおよび透明基材フィルム５４Ｂは、それぞれ、液晶表示装置の第２光拡散層５および第２支持フィルム６２として使用され、第１支持フィルム６１、偏光子６０および第２支持フィルム６２がこの順で積層された第２偏光板６、ならびに、この第２支持フィルム６２に直接積層された第２光拡散層５が得られる。 (1) Method 1 using a light diffusion film
As shown in FIG. 6A, the transparent base film 54B side of the light diffusion film 54 is laminated directly or via an adhesive layer on the polarizer 60 (on the side opposite to the first support film 61). In this way, the light diffusion layer 54A and the transparent base film 54B of the light diffusion film 54 are used as the second light diffusion layer 5 and the second support film 62 of the liquid crystal display device, respectively, and the first support film 61, The second polarizing plate 6 in which the polarizer 60 and the second support film 62 are laminated in this order, and the second light diffusion layer 5 directly laminated on the second support film 62 are obtained.
　（２）　光拡散フィルムを用いる方法２
　図６（ｂ）に示されるように、光拡散フィルム５４の透明基材フィルム５４Ｂ側が、第２偏光板６の第２支持フィルム上に直接または接着層を介して積層される。なお、ここでいう接着層は、粘着剤または接着剤から構成される。このようにして、第１支持フィルム６１、偏光子６０および第２支持フィルム６２がこの順で積層された第２偏光板６、ならびに、この第２支持フィルム６２上に直接または接着層を介して透明基材フィルム５４Ｂが積層され、また該透明基材フィルム５４Ｂに直接積層された第２光拡散層５が得られる。 (2) Method 2 using a light diffusion film
As shown in FIG. 6B, the transparent base film 54 </ b> B side of the light diffusion film 54 is laminated on the second support film of the second polarizing plate 6 directly or via an adhesive layer. In addition, an adhesive layer here is comprised from an adhesive or an adhesive agent. In this way, the first support film 61, the polarizer 60, and the second support film 62 are laminated in this order, and the second support film 62 is directly or via an adhesive layer. The transparent substrate film 54B is laminated, and the second light diffusion layer 5 laminated directly on the transparent substrate film 54B is obtained.
　（レーザ光の相対強度の測定方法）
　以下、レーザ光が第２偏光板の背面側の法線方向から入射したときの、第２光拡散層から出射するレーザ光の相対強度の測定方法について説明する。なお、「第２偏光板の背面側の法線方向」とは、第２偏光板６の平坦な表面に対する光入射側の法線方向をいう。 (Measurement method of relative intensity of laser light)
Hereinafter, a method for measuring the relative intensity of the laser light emitted from the second light diffusion layer when the laser light is incident from the normal direction on the back side of the second polarizing plate will be described. The “normal direction on the back side of the second polarizing plate” refers to the normal direction on the light incident side with respect to the flat surface of the second polarizing plate 6.
　図７は、第２偏光板の背面側の法線方向から入射し、第２光拡散層側へ出射するレーザ光の相対強度を測定するときの、レーザ光の入射方向と出射方向とを模式的に示した斜視図である。図７において、第２光拡散層の表面９１の背面側（図の下方側）から法線方向に入射したレーザ光９３に対し、第２光拡散層側の法線方向９２から角度φの方向に出射するレーザ光９４の強度を測定する。レーザ光９４の測定強度を入射したレーザ光９３の強度で割った値が相対強度となる。なお、レーザ光９４と、法線方向９２と、入射したレーザ光９３とは、全て同一平面（図７における平面９５）上となるように測定される。 FIG. 7 schematically shows the incident direction and the emission direction of the laser beam when measuring the relative intensity of the laser beam incident from the normal direction on the back side of the second polarizing plate and emitted to the second light diffusion layer side. FIG. In FIG. 7, the direction of the angle φ from the normal direction 92 on the second light diffusion layer side with respect to the laser light 93 incident in the normal direction from the back side (the lower side in the figure) of the surface 91 of the second light diffusion layer. The intensity of the laser beam 94 emitted from the laser beam is measured. A value obtained by dividing the measured intensity of the laser beam 94 by the intensity of the incident laser beam 93 is the relative intensity. Note that the laser beam 94, the normal direction 92, and the incident laser beam 93 are all measured on the same plane (plane 95 in FIG. 7).
　次に、このようにして測定される相対強度を角度（出射角φ）に対してプロットすることによって、相対強度が０．０００８％以下となる角度（出射角φ）を求める。図８は、第２光拡散層側から出射するレーザ光の相対強度を出射角φに対してプロットしたグラフの一例である。このグラフに示した如く、相対強度は出射角が０°すなわち図７の法線方向９２がピークであり、法線方向９２に対して出射角φが大きくなるほど相対強度は低下する傾向にある。図８に示す例では、相対強度が０．０００８％以下となるのは出射角φが４１°以上の場合であることがわかる。 Next, by plotting the relative intensity measured in this way against the angle (exit angle φ), an angle (exit angle φ) at which the relative intensity becomes 0.0008% or less is obtained. FIG. 8 is an example of a graph in which the relative intensity of laser light emitted from the second light diffusion layer side is plotted against the emission angle φ. As shown in this graph, the relative intensity has a peak in the outgoing angle of 0 °, that is, the normal direction 92 in FIG. 7, and the relative intensity tends to decrease as the outgoing angle φ increases with respect to the normal direction 92. In the example shown in FIG. 8, it is understood that the relative intensity is 0.0008% or less when the emission angle φ is 41 ° or more.
　（液晶表示装置の他の実施形態）
　図９に、本発明の液晶表示装置の他の実施形態を示す。図９の液晶表示装置が、図１の液晶表示装置と異なる点は、第１偏光板４と液晶セル１との間に位相差板８を配置した点である。この位相差板８は、液晶セル１の表面の法線方向における位相差がほぼゼロであり、液晶セル１の表面の法線方向（正面方向）には何ら光学的な作用を及ぼさず、正面方向に対して斜めの方向には位相差が発現するものであって、液晶表示装置を斜めから見たときに液晶セル１で生じる位相差を補償しようとするものである。これによって、より広い視野角が得られ、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８は、第１偏光板４と液晶セル１との間および第２偏光板６と液晶セル１との間の一方または両方に配置することができる。 (Other embodiment of a liquid crystal display device)
FIG. 9 shows another embodiment of the liquid crystal display device of the present invention. The liquid crystal display device of FIG. 9 is different from the liquid crystal display device of FIG. 1 in that a phase difference plate 8 is disposed between the first polarizing plate 4 and the liquid crystal cell 1. This phase difference plate 8 has substantially zero phase difference in the normal direction of the surface of the liquid crystal cell 1 and has no optical effect on the normal direction (front direction) of the surface of the liquid crystal cell 1. A phase difference appears in a direction oblique to the direction, and an attempt is made to compensate for the phase difference generated in the liquid crystal cell 1 when the liquid crystal display device is viewed obliquely. As a result, a wider viewing angle can be obtained, and better display quality and color reproducibility can be obtained. The retardation plate 8 can be disposed between the first polarizing plate 4 and the liquid crystal cell 1 and between or between the second polarizing plate 6 and the liquid crystal cell 1.
　位相差板８の例は、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、このフィルムを更に二軸延伸したもの、及び液晶性モノマーを光重合反応で分子配列を固定化したものを含む。位相差板８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ことが好ましい。具体的には、ＴＮモードの液晶表示セルには、例えば「ＷＶフィルム」（富士フィルム株式会社製）、ＳＴＮモードの液晶表示セルには、例えば「ＬＣフィルム」（新日本石油株式会社製）、ＩＰＳモードの液晶セルには、例えば二軸性位相差フィルム、ＶＡモードの液晶セルには、例えば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セルモードの液晶セルには例えば「ＯＣＢ用ＷＶフィルム」（富士フィルム株式会社製）などが好適に使用できる。 Examples of the phase difference plate 8 include those obtained by using a polycarbonate resin or a cyclic olefin polymer resin as a film, further biaxially stretching the film, and those obtained by fixing a molecular arrangement of a liquid crystalline monomer by a photopolymerization reaction. Since the phase difference plate 8 optically compensates for the alignment of the liquid crystal, it is preferable to use one having a refractive index characteristic opposite to that of the liquid crystal alignment. Specifically, for the liquid crystal display cell of TN mode, for example, “WV film” (manufactured by Fuji Film Co., Ltd.), for the liquid crystal display cell of STN mode, for example, “LC film” (manufactured by Nippon Oil Corporation), For IPS mode liquid crystal cell, for example, biaxial retardation film, for VA mode liquid crystal cell, for example, retardation plate combining A-plate and C-plate, biaxial retardation film, π cell mode For example, “OCV WV film” (manufactured by Fuji Film Co., Ltd.) can be suitably used for the liquid crystal cell.
　以下、実施例を挙げて本発明をより詳細に説明するが、本発明はこれらに限定されるものではない。 Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.
　［第１光拡散層の製造］
　（１）　光拡散板の作製
　スチレン−メタクリル酸メチル共重合体樹脂（屈折率１．５７）７４．５質量部、架橋ポリメタクリル酸メチル樹脂粒子（屈折率１．４９、重量平均粒子径３０μｍ）２５質量部、ベンゾトリアゾール系紫外線吸収剤（住友化学株式会社製の「スミソーブ２００」）０．５質量部、ヒンダードフェノール系酸化防止剤（熱安定剤）（チバ・スペシャリティー・ケミカルズ株式会社製の「ＩＲＧＡＮＯＸ１０１０」）０．２質量部をヘンシェルミキサーで混合した後、第２押出機で溶融混練して、フィードブロックに供給した。 [Production of first light diffusion layer]
(1) Production of light diffusion plate 74.5 parts by mass of styrene-methyl methacrylate copolymer resin (refractive index 1.57), crosslinked polymethyl methacrylate resin particles (refractive index 1.49, weight average particle diameter 30 μm) 25 parts by mass, 0.5 parts by mass of a benzotriazole UV absorber (Sumitomo Chemical "Sumisorb 200"), hindered phenolic antioxidant (thermal stabilizer) (Ciba Specialty Chemicals) “IRGANOX1010”) of 0.2 part by mass was mixed with a Henschel mixer, melt-kneaded with a second extruder, and supplied to the feed block.
　一方、スチレン樹脂（屈折率１．５９）９９．５質量部、ベンゾトリアゾール系紫外線吸収剤（住友化学株式会社製の「スミソーブ２００」）０．０７質量部、光安定剤（チバ・スペシャリティー・ケミカルズ株式会社製の「チヌビン７７０」）０．１３質量部をヘンシェルミキサーで混合した後、架橋シロキサン系樹脂粒子（東レダウコーニングシリコーン株式会社製の「トレフィルＤＹ３３−７１９」、屈折率１．４２、重量平均粒子径２μｍ）と共に、第１押出機で溶融混練して、フィードブロックに供給した。架橋シロキサン系樹脂粒子の添加量を調節することで、拡散板の全光線透過率Ｔｔを調節し、全光線透過率Ｔｔが６５％の光拡散板を作製した。 On the other hand, 99.5 parts by mass of a styrene resin (refractive index 1.59), 0.07 parts by mass of a benzotriazole-based ultraviolet absorber (“Sumisorb 200” manufactured by Sumitomo Chemical Co., Ltd.), a light stabilizer (Ciba Specialty) After mixing 0.13 parts by mass of “Chinubin 770” manufactured by Chemicals Co., Ltd. with a Henschel mixer, crosslinked siloxane-based resin particles (“Trefill DY33-719” manufactured by Toray Dow Corning Silicone Co., Ltd., refractive index of 1.42, Together with a weight average particle diameter of 2 μm), the mixture was melt kneaded by a first extruder and supplied to a feed block. By adjusting the addition amount of the crosslinked siloxane-based resin particles, the total light transmittance Tt of the diffusion plate was adjusted, and a light diffusion plate having a total light transmittance Tt of 65% was produced.
　なお、上記光拡散板は、上記第１押出機からフィードブロックに供給される樹脂が中間層（基層）となり、上記第２押出機からフィードブロックに供給される樹脂が表層（両面）となるように共押出成形を行い、厚さ２ｍｍ（中間層１．９０ｍｍ、表層０．０５ｍｍ×２）の３層からなる積層板となっている。また、全光線透過率ＴｔはＪＩＳ　Ｋ　７３６１に準拠して、ヘイズ・透過率計（株式会社村上色彩技術研究所製　ＨＲ−１００）を用いて測定した。 In the light diffusion plate, the resin supplied from the first extruder to the feed block becomes an intermediate layer (base layer), and the resin supplied from the second extruder to the feed block becomes a surface layer (both sides). The laminate is made of three layers having a thickness of 2 mm (intermediate layer 1.90 mm, surface layer 0.05 mm × 2). The total light transmittance Tt was measured using a haze / transmittance meter (HR-100, manufactured by Murakami Color Research Laboratory Co., Ltd.) in accordance with JIS K 7361.
　（２）　プリズムシート（光偏向構造板）の作製
　スチレン樹脂（屈折率１．５９）をプレス成形することで厚さ１ｍｍの平板を作製した。さらに、図２に示すような頂角がθ、頂点間の距離ｄが５０μｍである二等辺三角形の断面を有するプリズム部分３２２およびＶ字状の直線溝３２１が平行に配列形成されているプリズムシート３２に対応した形状の金属製金型を用いて、上記スチレン樹脂板を再プレス成形することにより、プリズムシートを作製した。尚、頂角θは、該プリズムシートが、後述する実施例の液晶表示装置の第１光拡散層の部材として組み込まれた際に、法線方向に対して７０°傾いた方向の輝度が法線方向の輝度の０％、１０％、２０％となるように調整された。 (2) Production of prism sheet (light deflecting structure plate) A styrene resin (refractive index: 1.59) was press-molded to produce a 1 mm thick flat plate. Further, as shown in FIG. 2, a prism sheet having prism portions 322 having an isosceles triangle cross section in which the apex angle is θ and the distance d between vertices is 50 μm, and V-shaped linear grooves 321 are arranged in parallel. Using a metal mold having a shape corresponding to 32, the styrene resin plate was re-press molded to produce a prism sheet. Note that the apex angle θ has a luminance in a direction inclined by 70 ° with respect to the normal line direction when the prism sheet is incorporated as a member of the first light diffusion layer of the liquid crystal display device of an embodiment to be described later. The brightness was adjusted to 0%, 10%, and 20% of the luminance in the line direction.
　（３）　第１光拡散層を有する液晶表示装置の作製
　後述する実施例に用いられる液晶表示装置のバックライト装置２に、上記光拡散板３１とプリズムシート３２ａ，３２ｂとを図１の配置のように積層した。この際、一方のプリズムシートのＶ字状の直線溝の方向がバックライト装置２の冷陰極管２１に対して略平行となるように配置され、他方のプリズムフィルムのＶ字状の直線溝の方向が、前者のプリズムシートのＶ字状の直線溝の方向と直交するように、プリズムシート３２ａ，３２ｂを積層した。 (3) Production of Liquid Crystal Display Device Having First Light Diffusing Layer The light diffusing plate 31 and the prism sheets 32a and 32b are arranged in the arrangement shown in FIG. The layers were laminated as follows. At this time, the V-shaped linear groove of one prism sheet is arranged so that the direction of the V-shaped linear groove is substantially parallel to the cold cathode tube 21 of the backlight device 2, and the V-shaped linear groove of the other prism film is arranged. The prism sheets 32a and 32b were laminated so that the direction was orthogonal to the direction of the V-shaped linear groove of the former prism sheet.
　［第２光拡散層の製造］
　＜製造例１＞
　（１）　転写用金属ロールの作製
　直径２００ｍｍの鉄ロール（ＪＩＳによるＳＴＫＭ１３Ａ）の表面に工業用クロムめっき加工を行い、ついで表面を鏡面研磨して鏡面金型を作製した。 [Production of second light diffusion layer]
<Production Example 1>
(1) Preparation of transfer metal roll Industrial chrome plating was performed on the surface of a 200 mm diameter iron roll (JIS STKM13A), and then the surface was mirror-polished to produce a mirror mold.
　（２）　第２光拡散層の調製
　ペンタエリスリトールトリアクリレート（６０質量部）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質量部）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質量％となるように調整して紫外線硬化性樹脂組成物を得た。尚、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。 (2) Preparation of second light diffusion layer Pentaerythritol triacrylate (60 parts by mass) and polyfunctional urethanized acrylate (reaction product of hexamethylene diisocyanate and pentaerythritol triacrylate, 40 parts by mass) in a propylene glycol monomethyl ether solution It mixed and it adjusted so that it might become solid content concentration 60 mass%, and obtained the 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質量部に対して、透光性微粒子として重量平均粒径が１２．０μｍのポリスチレン系粒子（積水化成品工業株式会社製　ＳＢＸ−１２）を３０質量部、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質量部添加し、固形分率が６０質量％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 mass of the solid content of the ultraviolet curable resin composition, polystyrene particles having a weight average particle diameter of 12.0 μm (SBX-12 manufactured by Sekisui Plastics Co., Ltd.) are used as translucent fine particles. 30 parts by mass, 5 parts by mass of “Lucirin TPO” (BASF Corp., chemical name: 2,4,6-trimethylbenzoyldiphenylphosphine oxide), which is a photopolymerization initiator, is added to a solid content ratio of 60% by mass. A coating solution was prepared by diluting with propylene glycol monomethyl ether.
　この塗布液を、厚さ８０μｍの平坦なトリアセチルセルロース（ＴＡＣ）フィルム（第２偏光板における偏光子の第２支持フィルム６２）上に塗布し、８０℃に設定した乾燥機中で１分間乾燥させた。塗布液が乾燥して紫外線硬化性樹脂組成物層が形成されたＴＡＣフィルムを、上記（１）で作製した金型の鏡面に、紫外線硬化性樹脂組成物層が金型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ＴＡＣ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、透光性微粒子５２が分散された透光性樹脂層５１からなる、図５（ａ）に示す構造の平坦な表面を有する第２光拡散層５（ＴＡＣフィルム付き）を得た。このとき透光性微粒子５２が分散された透光性樹脂層５１の厚さは２５．１μｍであった。 This coating solution was applied onto a flat triacetyl cellulose (TAC) film (second polarizer polarizing film 62 in the second polarizing plate) having a thickness of 80 μm and dried for 1 minute in a dryer set at 80 ° C. I let you. The TAC film on which the coating solution is dried and the ultraviolet curable resin composition layer is formed is a rubber roll so that the ultraviolet curable resin composition layer is on the mold side on the mirror surface of the mold prepared in (1) above. Press to make contact. In this state, light from a high-pressure mercury lamp having an intensity of 20 mW / cm 2 is irradiated from the TAC film side so that the amount of light in terms of h-line becomes 300 mJ / cm 2 to cure the ultraviolet curable resin composition layer, The 2nd light-diffusion layer 5 (with a TAC film) which has the flat surface of the structure shown to Fig.5 (a) which consists of the translucent resin layer 51 in which the fine particle 52 was disperse | distributed was obtained. At this time, the thickness of the translucent resin layer 51 in which the translucent fine particles 52 were dispersed was 25.1 μm.
　＜製造例２＞
　透光性微粒子として重量平均粒径が６．０μｍのポリスチレン系粒子（積水化成品工業株式会社製　ＳＢＸ−６）を４０質量部使用した以外は製造例１と同様にして、第２光拡散層を得た。このとき透光性微粒子５２が分散された透光性樹脂層５１の厚さは１５．５μｍであった。 <Production Example 2>
Second light diffusion layer in the same manner as in Production Example 1 except that 40 parts by mass of polystyrene-based particles (SBX-6 manufactured by Sekisui Plastics Co., Ltd.) having a weight average particle size of 6.0 μm were used as the light-transmitting fine particles. Got. At this time, the thickness of the translucent resin layer 51 in which the translucent fine particles 52 were dispersed was 15.5 μm.
　＜製造例３＞
　透光性微粒子として重量平均粒径が６．０μｍのポリスチレン系粒子（積水化成品工業株式会社製　ＳＢＸ−６）を１０質量部使用した以外は製造例１と同様にして、第２光拡散層を得た。このとき透光性微粒子５２が分散された透光性樹脂層５１の厚さは１３．４μｍであった。 <Production Example 3>
Second light diffusion layer in the same manner as in Production Example 1 except that 10 parts by mass of polystyrene-based particles (SBX-6 manufactured by Sekisui Plastics Co., Ltd.) having a weight average particle size of 6.0 μm were used as the light-transmitting fine particles. Got. At this time, the thickness of the translucent resin layer 51 in which the translucent fine particles 52 were dispersed was 13.4 μm.
　＜製造例４＞
　透光性微粒子として重量平均粒径が６．０μｍのポリスチレン系粒子（積水化成品工業株式会社製　ＳＢＸ−６）を７０質量部使用した以外は製造例１と同様にして、第２光拡散層を得た。このとき透光性微粒子５２が分散された透光性樹脂層５１の厚さは１３．７μｍであった。 <Production Example 4>
Second light diffusing layer in the same manner as in Production Example 1 except that 70 parts by mass of polystyrene-based particles (SBX-6 manufactured by Sekisui Plastics Co., Ltd.) having a weight average particle size of 6.0 μm were used as translucent fine particles. Got. At this time, the thickness of the translucent resin layer 51 in which the translucent fine particles 52 were dispersed was 13.7 μm.
　＜製造例５＞
　金型の鏡面に押し付けず、紫外線硬化樹脂側より、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た以外は、製造例１と同様にして、第２光拡散層を得た。このとき透光性微粒子５２が分散された透光性樹脂層５１の厚さは２７．２μｍであった。 <Production Example 5>
The UV curable resin composition layer is irradiated with light from a high pressure mercury lamp having an intensity of 20 mW / cm 2 from the UV curable resin side so as to be 300 mJ / cm 2 in terms of h-ray conversion amount without being pressed against the mirror surface of the mold. A second light diffusion layer was obtained in the same manner as in Production Example 1 except that was cured. At this time, the thickness of the translucent resin layer 51 in which the translucent fine particles 52 were dispersed was 27.2 μm.
　＜製造例６＞
　透光性微粒子として重量平均粒径が６．０μｍのポリスチレン系粒子（積水化成品工業株式会社製　ＳＢＸ−６）を４０質量部用いる以外は製造例５と同様にして、第２光拡散層を得た。このとき透光性微粒子５２が分散された透光性樹脂層５１の厚さは１６．１μｍであった。 <Production Example 6>
The second light diffusion layer was formed in the same manner as in Production Example 5 except that 40 parts by mass of polystyrene-based particles having a weight average particle size of 6.0 μm (SBX-6 manufactured by Sekisui Plastics Co., Ltd.) were used as the light-transmitting fine particles. Obtained. At this time, the thickness of the translucent resin layer 51 in which the translucent fine particles 52 were dispersed was 16.1 μm.
　［第２光拡散層の光拡散特性の測定］
　＜ヘイズ値の測定＞
　製造例１~６で得られた第２光拡散層について、ヘイズ値を測定した。測定結果を表１に示す。なお、フィルム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、フィルムにより拡散されて透過した拡散光線透過率（Ｔｄ）との比から下記式（１）：
　ヘイズ（％）＝（Ｔｄ／Ｔｔ）×１００　　　　　（１）
によりヘイズ値を求める。ここで、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）との和である。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、ヘイズ透過率計（株式会社村上色彩技術研究所製　ＨＭ−１５０）を用いて測定した。 [Measurement of light diffusion characteristics of second light diffusion layer]
<Measurement of haze value>
For the second light diffusion layers obtained in Production Examples 1 to 6, haze values were measured. The measurement results are shown in Table 1. In addition, from the ratio of the total light transmittance (Tt) representing the total amount of light transmitted through irradiation of the film and the diffused light transmittance (Td) diffused and transmitted by the film, the following formula (1):
Haze (%) = (Td / Tt) × 100 (1)
To obtain the haze value. Here, the total light transmittance (Tt) is the sum of the parallel light transmittance (Tp) and the diffused light transmittance (Td) transmitted coaxially with the incident light. Total light transmittance (Tt) and diffused light transmittance (Td) were measured using a haze transmittance meter (HM-150 manufactured by Murakami Color Research Laboratory Co., Ltd.) in accordance with JIS K 7361.
　サンプルの反りを防止するため、光学的に透明な粘着剤を用いて第２光拡散層に積層されたＴＡＣフィルム側をガラス基板に貼合して、第２光拡散層が表面となるようにし、その状態でガラス基板側から光を照射して全ヘイズを測定した。なお、ガラス基板およびＴＡＣフィルムは各ヘイズ値の測定に影響せず、ここでの測定値は第２光拡散層のヘイズ値と等価である。 In order to prevent the sample from warping, the TAC film side laminated on the second light diffusion layer is bonded to the glass substrate using an optically transparent adhesive so that the second light diffusion layer becomes the surface. In that state, the entire haze was measured by irradiating light from the glass substrate side. In addition, a glass substrate and a TAC film do not influence the measurement of each haze value, and a measured value here is equivalent to the haze value of a 2nd light-diffusion layer.
　内部ヘイズの測定は、フィルム表面にヘイズがほぼ０のトリアセチルセルロースフィルムをグリセリンで貼り付けて、フィルム外側の影響を消去することにより、全ヘイズの測定と同様にして行った。 The measurement of the internal haze was performed in the same manner as the measurement of the total haze by sticking a triacetyl cellulose film having a haze of almost 0 to the film surface with glycerin to eliminate the influence of the outside of the film.
　外部ヘイズは、上記全ヘイズおよび内部ヘイズの測定値から下式により求めた。
　外部ヘイズ（％）＝全ヘイズ（％）−内部ヘイズ（％）
　＜各出射角におけるレーザ光強度の測定＞
　また、製造例１~６で得られた第２光拡散層をガラス基板に貼合し、そのガラス基板側から第２光拡散層の法線方向に、波長５４３．５ｎｍのＨｅ−Ｎｅレーザからの平行光を照射し、第２光拡散層を構成する層のうち透光性微粒子が分散された透光性樹脂層から、ガラス基板表面の法線方向に対して０°~９０°の所定の角度（出射角）をなして出射されるレーザ光の強度を測定した。尚、測定には、横河電機（株）製の「３２９２　０３　オプティカルパワーセンサー」および「３２９２　オプティカルパワーメーター」を用いた。第２光拡散層に照射されたレーザ光の強度に対する、所定の出射角で出射されたレーザ光の強度の比率（相対強度）が０．０００８％以下となった出射角（°）及び法線方向から４０°傾いた方向に出射する相対強度（％）を表１に示す。
　この測定を行うに当たり、Ｈｅ−Ｎｅレーザを照射する光源は、前記ガラス基板から４３０ｍｍの位置に配置した。受光器である前記パワーセンサーは、レーザ光の出射点から２８０ｍｍの位置に配置し、このパワーセンサーを前記所定角度になるように動かして、出射されるレーザ光の強度をそれぞれ測定した。
　また、第２光拡散層に照射されたレーザ光の強度、すなわち、前記光源から照射されたレーザ光の強度は、第２光拡散層を貼合したガラス基板を設置せずに、前記光源から直接前記パワーセンサーに入射した光の強度を測定することで求めた。なお、当該強度の測定は、前記光源から７１０ｍｍ（＝４３０ｍｍ＋２８０ｍｍ）の位置に前記パワーセンサーを配置して行った。 The external haze was determined from the measured values of the total haze and internal haze according to the following formula.
External haze (%) = Total haze (%)-Internal haze (%)
<Measurement of laser light intensity at each emission angle>
In addition, the second light diffusion layer obtained in Production Examples 1 to 6 was bonded to a glass substrate, and from a He-Ne laser having a wavelength of 543.5 nm in the normal direction of the second light diffusion layer from the glass substrate side. The light transmitting resin layer in which the light transmitting fine particles are dispersed among the layers constituting the second light diffusion layer is irradiated at a predetermined angle of 0 ° to 90 ° with respect to the normal direction of the glass substrate surface. The intensity of the laser beam emitted at an angle (exit angle) was measured. For measurement, “3292 03 optical power sensor” and “3292 optical power meter” manufactured by Yokogawa Electric Corporation were used. The emission angle (°) and normal line where the intensity ratio (relative intensity) of the laser beam emitted at a predetermined emission angle to the intensity of the laser beam applied to the second light diffusion layer is 0.0008% or less. Table 1 shows the relative intensity (%) emitted in a direction inclined by 40 ° from the direction.
In performing this measurement, a light source for irradiating a He—Ne laser was disposed at a position of 430 mm from the glass substrate. The power sensor, which is a light receiver, was placed at a position 280 mm from the emission point of the laser beam, and the power sensor was moved to the predetermined angle to measure the intensity of the emitted laser beam.
Further, the intensity of the laser light irradiated to the second light diffusion layer, that is, the intensity of the laser light irradiated from the light source is determined from the light source without installing a glass substrate on which the second light diffusion layer is bonded. It was determined by measuring the intensity of light directly incident on the power sensor. In addition, the said intensity | strength measurement was performed by arrange | positioning the said power sensor in the position of 710 mm (= 430mm + 280mm) from the said light source.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-I000002
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-I000002
　（実施例１）
　液晶表示装置として、ＶＡモードのシャープ株式会社製３２型液晶テレビ（ＬＣ−３２Ｄ１０−Ｂ）のバックライト装置の前面側に、法線方向から７０°傾いた方向の輝度が法線方向の輝度の１０％である上記第１光拡散層を設置した液晶表示装置を用いた。次に、上記液晶表示装置の液晶セルにある両面の偏光板および位相差板を剥がして、住友化学株式会社製ヨウ素系通常偏光板（ＴＲＷ８４２ＡＰ７）を表裏にクロスニコルとなるように貼合し、偏光板の吸収軸が液晶セルの短辺と長辺に平行となるように貼合した。最後に、第２光拡散層として、製造例１で得たＴＡＣフィルム（第２偏光板における偏光子の支持フィルム）付きの第２光拡散層を前面側に貼合された上記ヨウ素系通常偏光板（第２偏光板の偏光子）の表面に貼合し、前面側から、第２光拡散層、第２偏光板、液晶セル、第１偏光板、第１光拡散層（プリズムシート、光拡散板）、バックライト装置を有する（図１の構成）液晶表示装置を作製した。 Example 1
As the liquid crystal display device, the luminance in the direction inclined by 70 ° from the normal direction is the luminance in the normal direction on the front side of the backlight device of the 32-inch liquid crystal television (LC-32D10-B) manufactured by Sharp Corporation in VA mode. A liquid crystal display device provided with the first light diffusion layer of 10% was used. Next, the polarizing plates on both sides and the retardation plate in the liquid crystal cell of the liquid crystal display device are peeled off, and an iodine-based normal polarizing plate (TRW842AP7) manufactured by Sumitomo Chemical Co., Ltd. is bonded to the front and back so as to be crossed Nicol, Bonding was performed so that the absorption axis of the polarizing plate was parallel to the short side and the long side of the liquid crystal cell. Finally, as the second light diffusion layer, the iodine-based normal polarization obtained by bonding the second light diffusion layer with the TAC film (the polarizer support film in the second polarizing plate) obtained in Production Example 1 to the front side. Bonded to the surface of the plate (polarizer of the second polarizing plate), and from the front side, the second light diffusion layer, the second polarizing plate, the liquid crystal cell, the first polarizing plate, the first light diffusion layer (prism sheet, light A liquid crystal display device having a diffusion plate) and a backlight device (configuration shown in FIG. 1) was produced.
　（実施例２および３）
　第１光拡散層として、法線方向から７０°傾いた方向の輝度が法線方向の輝度の０％である第１光拡散層（実施例２）、および、２０％である第１拡散層（実施例３）を用いたこと以外は実施例１と同様にして、液晶表示装置を作製した。 (Examples 2 and 3)
As the first light diffusion layer, the first light diffusion layer (Example 2) in which the luminance in the direction inclined by 70 ° from the normal direction is 0% of the luminance in the normal direction, and the first diffusion layer which is 20% A liquid crystal display device was produced in the same manner as in Example 1 except that (Example 3) was used.
　（実施例４）
　第２光拡散層として、製造例２で得た第２光拡散層を用いること以外は実施例１と同様にして、液晶表示装置を作製した。 Example 4
A liquid crystal display device was produced in the same manner as in Example 1 except that the second light diffusion layer obtained in Production Example 2 was used as the second light diffusion layer.
　（比較例１）
　第２光拡散層として、製造例３で得た第２光拡散層を用いること以外は実施例１と同様にして、液晶表示装置を作製した。 (Comparative Example 1)
A liquid crystal display device was produced in the same manner as in Example 1 except that the second light diffusion layer obtained in Production Example 3 was used as the second light diffusion layer.
　（比較例２）
　第２光拡散層として、製造例４で得た第２光拡散層を用いること以外は実施例１と同様にして、液晶表示装置を作製した。 (Comparative Example 2)
A liquid crystal display device was produced in the same manner as in Example 1 except that the second light diffusion layer obtained in Production Example 4 was used as the second light diffusion layer.
　（比較例３および４）
　第２光拡散層として、製造例５および６で得た第２光拡散層を用いること以外は実施例１と同様にして、液晶表示装置を作製した。 (Comparative Examples 3 and 4)
A liquid crystal display device was produced in the same manner as in Example 1 except that the second light diffusion layer obtained in Production Examples 5 and 6 was used as the second light diffusion layer.
　（評価）
　実施例１~４、比較例１~４で作製した液晶表示装置について、暗室にて目視評価を行った。また、２００ルクスの明室における目視評価も行った。結果を表２に示す。 (Evaluation)
The liquid crystal display devices produced in Examples 1 to 4 and Comparative Examples 1 to 4 were visually evaluated in a dark room. In addition, visual evaluation in a light room of 200 lux was also performed. The results are shown in Table 2.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
　表２に示されるように、実施例１~４の液晶表示装置は、暗室での評価において、液晶画面の正面方向（法線方向）に対する視野角が０°（正面）から６０°までの間で、階調の反転、階調の潰れ、色調、黒表示の白浮きおよび輝度変化に異常は全く認められず、いずれも良好であった。また、明室での評価においても、暗室での評価と同様に、良好な表示品位を示した。 As shown in Table 2, in the liquid crystal display devices of Examples 1 to 4, in the evaluation in the dark room, the viewing angle with respect to the front direction (normal direction) of the liquid crystal screen is between 0 ° (front) and 60 °. No abnormality was observed in gradation inversion, gradation collapse, color tone, white floating in black display, and luminance change, and all were good. In the evaluation in the bright room, the display quality was good as in the evaluation in the dark room.
　これに対して、比較例１の液晶表示装置は、斜めから見たときの輝度が低く、視野角が不十分であった。また、比較例２の液晶表示装置は、正面から見たときの輝度が低く、表示品位が不十分であった。また、比較例３および４の液晶表示装置は、暗室での表示品位は十分であるが、明室では画面が白っぽくなり、表示品位が不十分であった。 In contrast, the liquid crystal display device of Comparative Example 1 had a low luminance when viewed from an oblique direction and an insufficient viewing angle. Further, the liquid crystal display device of Comparative Example 2 had low luminance when viewed from the front, and display quality was insufficient. Further, the liquid crystal display devices of Comparative Examples 3 and 4 had sufficient display quality in the dark room, but the screen became whitish in the bright room, and the display quality was insufficient.
　（実施例５）
　液晶表示装置として、ＴＮモードのＴＥＣＯ社製２６型液晶テレビ（ＴＬ２６８６ＴＷ）を用いるほかは実施例１と同様に液晶表示装置を作製し、暗室および明室で目視評価を行った。暗室および明室のいずれにおいても、視野角が０°（正面）から６０°までの間で、階調の反転、階調の潰れ、色調、黒表示の白浮きおよび輝度変化に異常は全く認められず、良好な表示品位を示した。 (Example 5)
As a liquid crystal display device, a liquid crystal display device was produced in the same manner as in Example 1 except that a 26-inch liquid crystal television (TL2686TW) manufactured by TECO in TN mode was used, and visual evaluation was performed in a dark room and a bright room. In both the dark room and the bright room, when the viewing angle is between 0 ° (front) and 60 °, there are no abnormalities in gradation inversion, gradation collapse, color tone, white floating in black display, and luminance change. The display quality was good.
　（実施例６）
　液晶表示装置として、ＩＰＳモードのパナソニック株式会社製３２型液晶テレビ（ＶＩＥＲＡ　ＴＨ−３２ＬＺ８５）を用いるほかは実施例１と同様に液晶表示装置を作製し、暗室および明室で目視評価を行った。暗室および明室のいずれにおいても、視野角が０°（正面）から６０°までの間で、階調の反転、階調の潰れ、色調、黒表示の白浮きおよび輝度変化に異常は全く認められず、良好な表示品位を示した。 (Example 6)
A liquid crystal display device was produced in the same manner as in Example 1 except that a 32-inch liquid crystal television (VIERA TH-32LZ85) manufactured by Panasonic Corporation in IPS mode was used as the liquid crystal display device, and visual evaluation was performed in a dark room and a bright room. In both the dark room and the bright room, when the viewing angle is between 0 ° (front) and 60 °, there are no abnormalities in gradation inversion, gradation collapse, color tone, white floating in black display, and luminance change. The display quality was good.
　１：液晶セル
　１１ａ，１１ｂ：透明基板
　１２：液晶層
　２：バックライト装置
　２１：冷陰極管
　３：第１光拡散層
　３１：光拡散板
　３１１：基材
　３１２：拡散剤
　３２，３２ａ，３２ｂ：プリズムシート（光偏向構造板）
　４：第１偏光板
　５：第２光拡散層
　５１：透光性樹脂層
　５２：透光性微粒子
　５３：ハードコート層
　５４：光拡散フィルム
　５４Ａ：光拡散層
　５４Ｂ：透明基材フィルム
　６：第２偏光板
　６０：偏光子
　６１：第１支持フィルム
　６２：第２支持フィルム
　７１：発光面
　７２：円
　７３：観察面
　７４：投影像
　７５：最小半値幅
　８：位相差板
　９１：第２光拡散層の表面
　９２：法線方向
　９３，９４：レーザ光
　９５：平面。 1: Liquid crystal cell 11a, 11b: Transparent substrate 12: Liquid crystal layer 2: Backlight device 21: Cold cathode tube 3: First light diffusion layer 31: Light diffusion plate 311: Base material 312: Diffusing agent 32, 32a, 32b: Prism sheet (light deflection structure plate)
4: First polarizing plate 5: Second light diffusing layer 51: Translucent resin layer 52: Translucent fine particles 53: Hard coat layer 54: Light diffusing film 54A: Light diffusing layer 54B: Transparent substrate film 6: First Two polarizing plates 60: Polarizer 61: First support film 62: Second support film 71: Light emitting surface 72: Circle 73: Observation surface 74: Projected image 75: Minimum half-value width 8: Phase plate 91: Second light diffusion Layer surface 92: normal direction 93, 94: laser beam 95: plane.

Claims (12)

  1. 　一対の透明基板の間に液晶層が設けられてなる液晶セルと、
    　液晶セルの背面側に設けられたバックライト装置と、
    　前記バックライト装置と前記液晶セルとの間に配置された光拡散機能および／または光偏向機能を有する第１光拡散層と、
    　前記第１光拡散層と前記液晶セルとの間に配置された第１偏光板と、
    　前記液晶セルの前面側に配置された第２光拡散層と、
    　前記液晶セルと前記第２光拡散層との間に配置された第２偏光板とを備え、
    　前記第２光拡散層は、波長５４３．５ｎｍのレーザ光を背面側の法線方向から入射したときに、第２光拡散層の法線方向に入射するレーザ光の強度に対する、法線方向から４０°傾いた方向に出射するレーザ光の相対強度が０．０００２％~０．００１％である光拡散特性を有し、
    　前記第２光拡散層の外部ヘイズが１．０％未満である液晶表示装置。     A liquid crystal cell in which a liquid crystal layer is provided between a pair of transparent substrates;
    A backlight device provided on the back side of the liquid crystal cell;
    A first light diffusion layer having a light diffusion function and / or a light deflection function disposed between the backlight device and the liquid crystal cell;
    A first polarizing plate disposed between the first light diffusion layer and the liquid crystal cell;
    A second light diffusion layer disposed on the front side of the liquid crystal cell;
    A second polarizing plate disposed between the liquid crystal cell and the second light diffusion layer,
    The second light diffusion layer has a normal direction relative to the intensity of the laser light incident in the normal direction of the second light diffusion layer when laser light having a wavelength of 543.5 nm is incident from the normal direction on the back side. A light diffusion characteristic in which the relative intensity of laser light emitted in a direction inclined by 40 ° is 0.0002% to 0.001%;
    A liquid crystal display device, wherein an external haze of the second light diffusion layer is less than 1.0%.
  2. 　前記第２光拡散層の内部ヘイズが２０％以上７０％未満である、請求の範囲１に記載の液晶表示装置。 The liquid crystal display device according to claim 1, wherein an internal haze of the second light diffusion layer is 20% or more and less than 70%.
  3. 　前記第１光拡散層からの出射光は、法線方向から７０°傾いた方向の輝度が法線方向の輝度に対して２０％以下である配光特性を有し、且つ、非平行光を含む、請求の範囲１または２に記載の液晶表示装置。 The emitted light from the first light diffusion layer has a light distribution characteristic in which the luminance in a direction inclined by 70 ° from the normal direction is 20% or less with respect to the luminance in the normal direction, and non-parallel light is emitted. The liquid crystal display device according to claim 1, comprising the liquid crystal display device.
  4. 　前記第１光拡散層は、前記光拡散機能を有する光拡散板と、前記光偏向機能を有する光偏向構造板とを有し、前記光拡散板の前面側に前記光偏向構造板が設けられた、請求の範囲１~３のいずれかに記載の液晶表示装置。 The first light diffusion layer includes a light diffusion plate having the light diffusion function and a light deflection structure plate having the light deflection function, and the light deflection structure plate is provided on a front side of the light diffusion plate. The liquid crystal display device according to any one of claims 1 to 3.
  5. 　前記液晶セルが、ＴＮ方式液晶セル、ＩＰＳ方式液晶セル及びＶＡ方式液晶セルのいずれかである、請求の範囲１~４のいずれかに記載の液晶表示装置。 The liquid crystal display device according to any one of claims 1 to 4, wherein the liquid crystal cell is any one of a TN liquid crystal cell, an IPS liquid crystal cell, and a VA liquid crystal cell.
  6. 　前記第２偏光板が、偏光子と、該偏光子と液晶セルの間に配置される第１支持フィルムと、該偏光子と前記第２光拡散層の間に配置される第２支持フィルムとを有する請求の範囲１~５のいずれかに記載の液晶表示装置。 The second polarizing plate includes a polarizer, a first support film disposed between the polarizer and the liquid crystal cell, and a second support film disposed between the polarizer and the second light diffusion layer. The liquid crystal display device according to any one of claims 1 to 5, wherein
  7. 　前記第２光拡散層が、前記第２支持フィルムに直接積層されている請求の範囲６に記載の液晶表示装置。 The liquid crystal display device according to claim 6, wherein the second light diffusion layer is directly laminated on the second support film.
  8. 　前記第２光拡散層の背面側の面が透明基材フィルムに直接積層され、且つ該透明基材フィルムの第２光拡散層とは反対の面が前記第２支持フィルムに直接または接着層を介して積層されている請求の範囲６に記載の液晶表示装置。 The back side surface of the second light diffusing layer is directly laminated on the transparent base film, and the surface opposite to the second light diffusing layer of the transparent base film is directly or on the second support film. The liquid crystal display device according to claim 6, wherein the liquid crystal display device is stacked via the liquid crystal display device.
  9. 前記第２光拡散層と前記第２支持フィルムとの組み合わせが、透明基材フィルムの一方の面に直接、光拡散層が形成されている光拡散フィルムからなる、請求の範囲７に記載の液晶表示装置。 The liquid crystal according to claim 7, wherein the combination of the second light diffusion layer and the second support film comprises a light diffusion film in which a light diffusion layer is formed directly on one surface of the transparent substrate film. Display device.
  10. 　透明基材フィルムの一方の面に直接または接着層を介して光拡散層が形成されている光拡散フィルムであって、該光拡散層は、波長５４３．５ｎｍのレーザ光を背面側の法線方向から入射したときに、該光拡散層の法線方向に入射するレーザ光の強度に対する、法線方向から４０°傾いた方向に出射するレーザ光の相対強度が０．０００２％~０．００１％である光拡散特性を有し、該光拡散層の外部ヘイズが１．０％未満であること特徴とする光拡散フィルム。 A light diffusion film in which a light diffusion layer is formed directly or via an adhesive layer on one surface of a transparent substrate film, and the light diffusion layer emits laser light having a wavelength of 543.5 nm on the back side normal line The relative intensity of laser light emitted in a direction inclined by 40 ° from the normal direction with respect to the intensity of laser light incident in the normal direction of the light diffusion layer when incident from the direction is 0.0002% to 0.001 % Light diffusing properties, and the light diffusing layer has an external haze of less than 1.0%.
  11. 　請求の範囲６に記載の液晶表示装置に使用される請求の範囲１０に記載の光拡散フィルムであって、
    　前記光拡散層および前記透明基材フィルムが、それぞれ、前記液晶表示装置の第２光拡散層および第２支持フィルムとして使用される、光拡散フィルム。     The light diffusing film according to claim 10, which is used in the liquid crystal display device according to claim 6,
    The light diffusion film in which the light diffusion layer and the transparent substrate film are used as a second light diffusion layer and a second support film of the liquid crystal display device, respectively.
  12. 　請求の範囲６に記載の液晶表示装置に使用される請求の範囲１０に記載の光拡散フィルムであって、
    　前記透明基材フィルムが、前記液晶表示装置の第２偏光板の第２支持フィルム側に直接または接着層を介して貼合される、光拡散フィルム。     The light diffusing film according to claim 10, which is used in the liquid crystal display device according to claim 6,
    The light-diffusion film by which the said transparent base film is bonded directly or through the contact bonding layer side with the 2nd support film side of the 2nd polarizing plate of the said liquid crystal display device.
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