WO2007129609A1 - Élément d'affichage à cristaux liquides comportant une feuille prismatique, et dispositif d'affichage à cristaux liquides utilisant l'élément d'affichage à cristaux liquides - Google Patents

Élément d'affichage à cristaux liquides comportant une feuille prismatique, et dispositif d'affichage à cristaux liquides utilisant l'élément d'affichage à cristaux liquides Download PDF

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Publication number
WO2007129609A1
WO2007129609A1 PCT/JP2007/059180 JP2007059180W WO2007129609A1 WO 2007129609 A1 WO2007129609 A1 WO 2007129609A1 JP 2007059180 W JP2007059180 W JP 2007059180W WO 2007129609 A1 WO2007129609 A1 WO 2007129609A1
Authority
WO
WIPO (PCT)
Prior art keywords
prism
light
liquid crystal
crystal display
prism sheet
Prior art date
Application number
PCT/JP2007/059180
Other languages
English (en)
Japanese (ja)
Inventor
Tomoyoshi Yamashita
Yuji Nishinaka
Original Assignee
Mitsubishi Rayon Co., Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Mitsubishi Rayon Co., Ltd. filed Critical Mitsubishi Rayon Co., Ltd.
Priority to JP2007524116A priority Critical patent/JPWO2007129609A1/ja
Publication of WO2007129609A1 publication Critical patent/WO2007129609A1/fr

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Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/04—Prisms
    • G02B5/045—Prism arrays
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0033—Means for improving the coupling-out of light from the light guide
    • G02B6/005—Means for improving the coupling-out of light from the light guide provided by one optical element, or plurality thereof, placed on the light output side of the light guide
    • G02B6/0053—Prismatic sheet or layer; Brightness enhancement element, sheet or layer
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0065—Manufacturing aspects; Material aspects
    • 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
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0013—Means for improving the coupling-in of light from the light source into the light guide
    • G02B6/0015—Means for improving the coupling-in of light from the light source into the light guide provided on the surface of the light guide or in the bulk of it
    • G02B6/002—Means for improving the coupling-in of light from the light source into the light guide provided on the surface of the light guide or in the bulk of it by shaping at least a portion of the light guide, e.g. with collimating, focussing or diverging surfaces
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0033—Means for improving the coupling-out of light from the light guide
    • G02B6/0035—Means for improving the coupling-out of light from the light guide provided on the surface of the light guide or in the bulk of it
    • G02B6/0038—Linear indentations or grooves, e.g. arc-shaped grooves or meandering grooves, extending over the full length or width of the light guide
    • 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
    • G02F1/133507—Films for enhancing the luminance
    • 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
    • G02F1/13356—Structural association of cells with optical devices, e.g. polarisers or reflectors characterised by the placement of the optical elements
    • G02F1/133567—Structural association of cells with optical devices, e.g. polarisers or reflectors characterised by the placement of the optical elements on the back side

Definitions

  • the present invention relates to a liquid crystal display element used in combination with a backlight (surface light source device). Furthermore, this invention relates to the liquid crystal display device which combines a liquid crystal display element and a backlight.
  • a liquid crystal display device is basically composed of a backlight and a liquid crystal display element.
  • an edge light type is often used from the viewpoint of making the liquid crystal display device compact.
  • an edge light type backlight at least one end surface of a rectangular plate-shaped light guide is used as a light incident end surface, and a linear shape such as a straight tube fluorescent lamp is formed along the light incident end surface.
  • a rod-shaped primary light source is disposed, and light emitted from the primary light source is introduced into the light guide from the light incident end surface of the light guide, and is one of the two main surfaces of the light guide. What is emitted from the light exit surface is widely used.
  • a backlight In such a backlight, light emitted in an oblique direction from the light exit surface of the light guide is guided by light from the light guide in a plane orthogonal to both the light incident end surface and the light exit surface of the light guide.
  • An optical deflecting element is used to deflect toward the exit surface normal.
  • the light deflection element is typically a prism sheet. In this prism sheet, one surface is a flat surface and the other surface is a prism row forming surface.
  • the prism array forming surface is formed by arranging a large number of prism arrays in parallel with each other at a predetermined pitch.
  • the characteristics required for a surface light source device for a liquid crystal display device include a high light intensity and a light guide for exhibiting a required optical function.
  • the surface structure such as the mat structure and the lens array arrangement structure formed mainly on the light emitting surface of the body or on the back surface on the opposite side may be difficult to see.
  • the prism row forming surface of the prism sheet of the surface light source device is disposed so as to face the light guide (that is, the prism row forming surface is disposed on the light guide light emitting surface).
  • the light incident surface on which light from the light enters.
  • a prism sheet opposite to the light entrance surface
  • the surface structural force S of the light guide may be visually recognized. Therefore, as described in Japanese Patent Laid-Open No. 6-324205 (Patent Document 1) and Japanese Patent Laid-Open No. 7-151909 (Patent Document 2), the prism sheet has a surface opposite to the prism array forming surface. It is conceivable to apply a technique for providing a fine uneven shape to make it difficult to visually recognize the surface structure of the light guide while maintaining high luminance.
  • Patent Document 1 JP-A-6-324205
  • Patent Document 2 JP-A-7-151909
  • the surface light source device there is a problem that uneven luminance due to the prism sheet is easily recognized as a high-intensity light source is used as a primary light source.
  • a defect due to a defect in the die for manufacturing the prism sheet brightness unevenness may be visually recognized due to a defective form of the prism sheet based on the defect.
  • an adhesive protective sheet is affixed to protect the prism array forming surface after the prism sheet is manufactured. After the adhesive protective sheet is peeled off when manufacturing the surface light source device, the adhesive of the protective sheet adheres to the top of the prism array. When it remains, brightness unevenness may be visually recognized due to this adhesive residue adhesive.
  • the present invention provides a liquid crystal display device capable of concealing optical defects while suppressing a decrease in luminance with almost no increase in cost, and a liquid crystal display element used therefor The purpose is to provide.
  • a liquid crystal display element used in combination with a surface light source device
  • a first surface of a prism sheet is bonded to a side of the liquid crystal display element on which light emitted from the surface light source device is incident, and a second surface opposite to the first surface of the prism sheet is a prism array.
  • the prism array forming surface has a plurality of prism arrays substantially parallel to each other. It is formed by arranging so as to extend to
  • the prism row forming surface has a roughened portion extending along the prism row between the prism rows adjacent to each other, and a surface of the roughened portion is formed by a prism surface of the prism row.
  • the roughening section has an arrangement pitch of 0.
  • the first surface of the prism sheet is bonded to the liquid crystal display element on the side on which light generated by the surface light source device is incident by a bonding material.
  • the bonding material is an adhesive or a self-adsorbing resin.
  • the prism rows are arranged concentrically.
  • a primary light source Comprising: a primary light source; a light guide that is guided and guided by light emitted from the primary light source; and the liquid crystal display element with the prism sheet,
  • the light guide includes a light incident end surface on which light emitted from the primary light source enters and a light exit surface from which the guided light exits, and the primary light source includes a light incident end surface of the light guide.
  • the liquid crystal display element with a prism sheet is disposed such that the prism row forming surface of the prism sheet faces the light emitting surface of the light guide.
  • the prism row forming surface of the prism sheet is a rough surface extending along the prism row between adjacent prism rows. Since the liquid crystal display device is configured by using the liquid crystal display element to which the prism sheet is bonded, based on the light diffusion in the roughened surface portion, it is based on the defects of the prism sheet manufacturing mold.
  • Luminance unevenness caused by defective form of prism sheet, prism array after peeling of the adhesive protective sheet based on the adhesion of the adhesive protective sheet The effect of improving the luminance unevenness caused by the residual adhesion of the protective sheet pressure sensitive adhesive, that is, the effect of concealing optical defects, is obtained, and the decrease in luminance is small.
  • FIG. 1 A schematic partially cutaway perspective view showing one embodiment of a liquid crystal display device using a liquid crystal display element with a prism sheet according to the present invention.
  • FIG. 5 A schematic cross-sectional view for explaining the production of a mold member for manufacturing a prism sheet.
  • FIG. 7 is a schematic perspective view showing a roll mold used in the manufacture of a prism sheet.
  • FIG. 8 is a schematic exploded perspective view showing a roll mold used in the manufacture of a prism sheet.
  • FIG. 9 is a diagram showing the luminance distribution of the surface light source.
  • FIG. 10 is a diagram showing the luminance distribution of the surface light source.
  • FIG. 11 A schematic partial enlarged cross-sectional view of one embodiment of a prism sheet constituting a liquid crystal display element with a prism sheet according to the present invention.
  • FIG. 12 is a schematic partial enlarged bottom view of the prism sheet of FIG.
  • FIG. 13 is a schematic diagram showing a cross-sectional shape of a valley portion of the prism sheet of FIG.
  • FIG. 14 A schematic partially cutaway perspective view showing one embodiment of a liquid crystal display device using a liquid crystal display element with a prism sheet according to the present invention.
  • FIG. 17 is a cross-sectional enlarged view of the transfer surface portion of the prism row and the valley portion of the mold member obtained in the example. Is true.
  • FIG. 1 is a schematic partially cutaway perspective view showing one embodiment of a liquid crystal display device using a liquid crystal display element with a prism sheet according to the present invention
  • FIG. 2 is a schematic partial sectional view thereof.
  • the liquid crystal display device of this embodiment includes an edge light type surface light source device and a liquid crystal display element with a prism sheet.
  • the edge light type surface light source device includes at least one side end face as a light incident end face 31 and one light guide face 3 having a light exit face 33 as one surface substantially orthogonal thereto.
  • the linear primary light source 1 disposed opposite to the light incident end surface 31 of the light guide 3 and covered with the light source reflector 2 and the back surface 34 of the light guide 3 opposite to the light exit surface 33
  • the light reflecting element 5 is disposed to face each other.
  • the light guide 3 is disposed in parallel with the XY plane and has a rectangular plate shape as a whole.
  • the light guide 3 has four side end faces, of which a small number of the pair of side end faces parallel to the YZ plane. At least one side end face is a light incident end face 31.
  • the light incident end face 31 is arranged to face the primary light source 1, and light emitted from the primary light source 1 enters the light incident end face 31 and is introduced into the light guide 3.
  • the light source may be disposed opposite to another side end face such as the side end face 32 opposite to the light incident end face 31.
  • the two main surfaces that are substantially orthogonal to the light incident end surface 31 of the light guide 3 are respectively positioned substantially parallel to the XY plane, and one of the surfaces (the upper surface in the figure) is the light emitting surface 33.
  • the light emitting surface 33 With a directional light emitting mechanism including a rough surface, the light incident from the light incident surface 31 is guided through the light guide 3 while the light incident from the light incident surface 31 is guided through the light incident surface 31.
  • light having directivity is emitted in a plane (XZ plane) orthogonal to the light exit surface 33.
  • the peak direction (peak light) of the emitted light intensity distribution in this XZ in-plane distribution is the angle formed by the light emitting surface 33.
  • the angle is, for example, 10 to 40 degrees, and the full width at half maximum of the emitted light luminous intensity distribution is, for example, 10 to 40 degrees.
  • the rough surface or lens array formed on the surface of the light guide 3 should have an average inclination angle ⁇ a in the range of 0.5 to 15 degrees according to IS04287 / 1-1984. It is preferable from the viewpoint of improving the uniformity of the luminance in the interior.
  • the average inclination angle ⁇ a is more preferably in the range of 1 to 12 degrees, and more preferably in the range of 1.5 to 11 degrees.
  • the average inclination angle ⁇ a is preferably set to an optimum range by the ratio (L / d) of the thickness (d) of the light guide 3 and the length (L) in the direction in which the incident light propagates. .
  • the average inclination angle ⁇ a when using a light guide 3 having an L / d of about 20 to 200, it is preferable to set the average inclination angle ⁇ a to 0.5 to 7.5 degrees, and more preferably: Is in the range of -5 degrees, more preferably in the range of 1.5-4 degrees.
  • the average inclination angle ⁇ a when a light guide 3 having L / d of about 20 or less is used, it is preferable to set the average inclination angle ⁇ a to 7 to 12 degrees S, more preferably 8 to 11 degrees. Range.
  • the average inclination angle ⁇ a of the rough surface formed on the light guide 3 is measured according to IS04287Z1-1984 using a stylus type surface roughness meter, and the coordinate in the measurement direction is X From the obtained gradient function f (X), the following equations (1) and (2)
  • the light guide 3 preferably has a light emission rate in the range of 0.5 to 5%, more preferably in the range of 1 to 3%.
  • the light emission rate By setting the light emission rate to 0.5% or more, the amount of light emitted from the light guide 3 is increased and sufficient luminance tends to be obtained.
  • the light emission rate By setting the light emission rate to 5% or less, emission of a large amount of light in the vicinity of the primary light source 1 is prevented, and attenuation of the emitted light in the X direction within the light emission surface 33 is reduced. The luminance uniformity on surface 33 tends to improve.
  • the angle of the peak light in the emission light intensity distribution (in the XZ plane) of the light emitted from the light emission surface becomes the light emission.
  • the full width at half maximum of the emitted light intensity distribution (in the XZ plane) in the XZ plane that is in the range of 50 to 80 degrees with respect to the normal of the surface and is perpendicular to both the light incident end face and the light emitting face is 10 to 40 degrees.
  • Light with such highly directional emission characteristics can be emitted from the light guide 3, and the emission direction can be efficiently deflected by the prism sheet 4 bonded to the liquid crystal display element 8.
  • a surface light source having high power and brightness can be provided.
  • the light emission rate from the light guide 3 is defined as follows. From the light intensity (I) of the emitted light at the edge on the light incident end surface 31 side of the light emitting surface 33 and the edge on the light incident end surface 31 side
  • the constant ⁇ is the light output rate
  • the light guide 3 per unit length (length corresponding to the light guide thickness d) in the X direction orthogonal to the light incident end surface 31 on the light output surface 33 It is a ratio (percentage:%) at which light is emitted from the light source.
  • This light emission rate ⁇ is obtained from the gradient by plotting the relationship between the logarithm of the light intensity of the light emitted from the light exit surface 23 on the vertical axis and (L / d) on the horizontal axis. be able to.
  • the light diffusing fine particles are mixed and dispersed inside the light guide.
  • a neutral light emitting mechanism may be provided.
  • the back surface 34 which is the main surface to which no directional light emitting mechanism is provided, controls the directivity on a surface (YZ surface) parallel to the primary light source 1 of the light emitted from the light guide 3.
  • a prism array forming surface is formed by arranging a number of prism arrays 1J extending in a direction crossing the surface 31, more specifically in a direction substantially perpendicular to the light incident end surface 31 (X direction).
  • the prism row on the rear surface 34 of the light guide 3 can have an arrangement pitch in the range of 10 to 100 ⁇ m, preferably 30 to 60 111, for example.
  • the prism array on the back surface 34 of the light guide 3 can have an apex angle in the range of 85 to 110 degrees, for example. This is because by setting the apex angle within this range, the light emitted from the light guide 3 can be condensed appropriately, and the luminance as a surface light source device can be improved.
  • the angle is more preferably in the range of 90 to 100 degrees.
  • the light guide 3 is not limited to the shape shown in FIG. 1, but can have various shapes such as a light incident end face having a thick shape and a wedge shape.
  • the light guide 3 can be made of a synthetic resin having a high light transmittance.
  • synthetic resin include methacrylic resin, acrylic resin, polycarbonate resin, polyester resin, and chlorinated resin.
  • methacrylic resins are optimal because of their high light transmittance, heat resistance, mechanical properties, and moldability.
  • a methacrylic resin is a resin mainly composed of methyl methacrylate, and preferably has a methyl methacrylate content of 80% by weight or more.
  • the structural surface can also be formed using heat or a photo-curable resin.
  • an active energy line curable resin is applied on the surface of a transparent substrate such as a polyester film, an acrylic resin, a polycarbonate resin, a vinyl chloride resin, a polymethacrylimide resin, or a transparent substrate.
  • a rough surface structure or a lens array arrangement structure may be formed, and such a sheet may be bonded and integrated on a separate transparent substrate by a method such as adhesion or fusion.
  • the active energy ray-curable resin it is possible to use polyfunctional (meth) acrylic compounds, vinyl compounds, (meth) acrylic acid esters, aryl compounds, (meth) acrylic acid metal salts, and the like.
  • the primary light source 1 is a linear light source extending in the Y direction.
  • a light lamp or a cold cathode tube can be used.
  • the primary light source 1 may be further installed on the opposite side end surface as needed, not only when it is installed facing one side end surface of the light guide 3. You can also.
  • the light source reflector 2 guides the light from the primary light source 1 to the light guide 3 with little loss.
  • a plastic film having a metal-deposited reflective layer on the surface can be used as the material.
  • the light source reflector 2 is rubbed from the outer surface of the edge of the light reflecting element 5 to the edge of the light emitting surface of the light guide 3 through the outer surface of the primary light source 1.
  • a reflection member similar to the light source reflector 2 can be attached to the side end face other than the light incident end face 31 of the light guide 3.
  • the light reflecting element 5 for example, a plastic sheet having a metal-deposited reflecting layer on the surface can be used.
  • the liquid crystal display element 8 a well-known transmissive liquid crystal display element can be used without particular limitation.
  • this transmissive liquid crystal display element for example, a liquid crystal 83 is interposed between two translucent substrates 81, 82 made of a glass sheet or a synthetic resin sheet arranged in parallel with each other, and formed on the lower surface of the substrate 82.
  • An example of performing image display by applying a voltage according to an image signal between the transparent electrode 85 and a required one of the pixel electrodes 84 formed on the upper surface of the substrate 81 is exemplified.
  • it may include a color filter for color display, a pair of polarizing plates as a polarizer and an analyzer, and other known appropriate functional members.
  • the liquid crystal display element 8 is disposed above the light emitting surface 33 of the light guide 3.
  • the light exit surface (first surface) of the prism sheet 4 as a light deflecting element on the side (lower side in the figure) on which light emitted from the surface light source device of the liquid crystal display element 8 is incident 42 are joined.
  • This joining is performed by a joining material 86.
  • the bonding material 86 is not particularly limited as long as it has translucency.
  • an adhesive or a self-adsorbing resin is preferable.
  • Adhesives include UV curable adhesives and those commonly known as pressure sensitive adhesives, and it has excellent heat resistance, electrical insulation, and chemical resistance.
  • main component is polydimethylsiloxane
  • transparent acrylic adhesive with excellent weather resistance for example, main component is polybutyl acrylate, polyoctyl acrylate
  • resin with thermoplasticity at relatively low temperature Hot melt type adhesives (for example, those based on ethylene / vinyl acetate copolymer) are effective.
  • the light incident surface (second surface) 41 opposite to the light exit surface 42 of the prism sheet 4 is a prism row forming surface formed by arranging a plurality of prism rows so as to extend substantially parallel to each other. ing. Thereby, the liquid crystal display element 8 with the prism sheet 4 is formed.
  • the prism sheet 4 constitutes a surface light source that emits light along the direction of the normal direction of the light guide surface of the light guide, together with the primary light source 1 and the light guide 3, in terms of optical function.
  • the prism sheet 4 is joined and integrated with the liquid crystal display element 8 to form a liquid crystal display element with a prism sheet. Therefore, in this specification, for the sake of convenience, the members constituting the surface light source as described above are used.
  • a surface light source device is referred to as a surface light source device excluding the prism sheet.
  • the prism sheet 4 is disposed above the light emitting surface 33 of the light guide 3.
  • the two principal surfaces 41 and 42 of the prism sheet 4 are arranged in parallel with each other as a whole, and are located parallel to the XY plane as a whole.
  • One of the main surfaces 41, 42 (the main surface located on the light emitting surface 33 side of the light guide 3) is a light incident surface 41, and the other is a light emitting surface 42.
  • the light exit surface 42 is a flat surface parallel to the light exit surface 33 of the light guide 3.
  • the light incident surface 41 is a prism row forming surface in which a large number of prisms IJ411 extending in the Y direction are arranged in parallel to each other.
  • FIG. 3 shows a schematic partial enlarged cross-sectional view of the prism sheet 4.
  • the prism sheet 4 can be composed of a transparent base material 43 and a prism portion 44.
  • the upper surface of the transparent substrate 43 forms the light exit surface 42
  • the lower surface of the prism portion 44 forms the light incident surface 41.
  • the transparent substrate 43 is preferably made of a material that transmits active energy rays such as ultraviolet rays and electron beams.
  • a flexible glass plate or the like can be used.
  • a transparent resin sheet or film such as a resin, an acrylic resin, a polycarbonate resin, a salt vinyl resin, or a polymetalinoleimide resin is preferable.
  • polymethylmetatalylate having a refractive index lower than the refractive index of the prism portion 44 and low surface reflectance a mixture of polymethyl acrylate and polyvinylidene fluoride resin, polycarbonate resin, polyethylene terephthalate, etc. What consists of a polyester-type resin is preferable.
  • the thickness of the transparent substrate 43 is, for example, about 50 ⁇ m to 500 ⁇ m.
  • the transparent base material 43 has its surface subjected to an adhesion improvement treatment such as an anchor coat treatment in order to improve the adhesion between the prism portion 44 made of an active energy line curable resin and the transparent base material 43. Is preferred.
  • the upper surface of the prism portion 44 is a flat surface, and is joined to the lower surface of the transparent base material 43.
  • the lower surface of the prism portion 44, that is, the light incident surface 41 is a prism row forming surface, and a plurality of prisms 1J41 1 extending in the Y direction are arranged in parallel with each other and between adjacent prism rows. And a roughened surface 412 extending in the Y direction along the prism row.
  • the thickness of the prism portion 44 is, for example, 10 to 500 ⁇ .
  • the arrangement pitch P of the prism array 41 1 is, for example, 10 ⁇ m to 500 ⁇ m.
  • the prism row 41 1 has two prism surfaces 41 la and 41 lb force. These prism surfaces may be optically sufficiently smooth surfaces (mirror surfaces), or may be rough surfaces having a roughening degree smaller than the surface of the roughening portion 412.
  • the prism surface is preferably a mirror surface from the viewpoint of maintaining desired optical characteristics by the prism sheet.
  • the region near the roughened portion of the prism surface may be roughened.
  • the degree of roughening indicates the degree of roughening, and can be expressed by, for example, centerline average roughness Ra or ten-point average roughness.
  • the apex angle ⁇ of the prism array 41 1 is preferably in the range of 40 to 150 °.
  • the apex angle ⁇ of the prism array is in the range of about 80 to 100 °. Yes, preferably in the range of 85-95 °.
  • the prism sheet 4 is arranged so that the prism row forming surface is on the light guide 3 side as in the above embodiment, the apex angle ⁇ of the prism row 41 1 is in the range of about 40 to 75 °. Preferably in the range of 45-70 ° .
  • a surface having an irregular cross-sectional shape is also referred to as a rough surface.
  • the width W of the roughened portion 412 is 0.04 times to 0.5 times the arrangement pitch P of the prism row 411. It is 0.08 times to 0.3 times. Is more preferably 0.1 times to 0.2 times. This is because if the width W of the roughened portion 412 is within the range of 0.04 to 0.5 times the arrangement pitch P, the desired observation direction range based on the light diffusion in the roughened portion 412 This is because the effect of concentrating the light amount and the effect of improving the brightness unevenness can be obtained, and the reduction of the light deflection effect toward the normal light exit surface of the light guide by the prism IJ411 can be reduced.
  • the surface roughness of the roughened portion 412 is preferably 0.3 to 2 xm in terms of the center line average roughness Ra, more preferably 0.4 to 1.7 m.
  • the average roughness Rz is preferably 1 to 3 ⁇ m, and more preferably 1.3 to 2.7 zm.
  • the two prism surfaces 41 la and 41 lb of the prism array 411 may be rough surfaces having a roughening degree smaller than the surface of the roughening part 412.
  • the roughness of the prism surfaces 41 la and 41 lb is preferably less than 0 ⁇ 3 ⁇ at the centerline average roughness Ra, more preferably 0 ⁇ 1 / im or less, and a 10-point average
  • the roughness Rz is preferably less than 1 ⁇ m, more preferably 0.5 / im or less.
  • the surface shape of the roughened portion 412 or the prism surface 41 la, 41 lb of the prism array 411 is measured using, for example, an ultra-deep shape measuring microscope (for example, VK-8500 manufactured by Keyence Corporation) ]).
  • the entire shape of the XZ cross section excluding the shape based on the fine structure of the roughened portion 412 (or the shape based on the fine structure is averaged and connected by a smooth line) is as shown in FIG. A concave curve is formed downward.
  • the overall shape of the XZ cross section of the roughened portion 412 may be a planar shape parallel to the XY plane.
  • the roughened portion and the prism surface are distinguished from each other by the degree of roughening, and the portion having a large degree of roughening is called a roughened portion, which is a mirror surface or roughened surface. The small part of the degree is the prism surface.
  • the prism portion 44 is made of, for example, an active energy ray-curable resin and preferably has a high refractive index from the viewpoint of improving the luminance of the surface light source device. 1. 55 or more, more preferably 1.6 or more.
  • the active energy ray curable resin for forming the prism portion 44 is not particularly limited as long as it is cured with active energy rays such as ultraviolet rays and electron beams.
  • active energy rays such as ultraviolet rays and electron beams.
  • (meth) acrylate resins such as polyester (meth) acrylate, epoxy (meth) acrylate and urethane (meth) acrylate.
  • (meth) acrylate resins are particularly preferable from the viewpoint of optical properties and the like.
  • the active energy ray-curable composition used for such a cured resin includes a polyfunctional acrylate and / or a polyfunctional metatalylate (hereinafter referred to as a polyvalent (meta)) in terms of handling property, properties and curability. It is preferable to use as a main component a monoacrylate and / or monomethacrylate (hereinafter referred to as mono (meth) acrylate) and a photopolymerization initiator by active energy rays.
  • Typical polyfunctional (meth) acrylates include polyol poly (meth) acrylate, polyester poly (meth) acrylate, epoxy poly (meth) acrylate, urethane poly (meth) acrylate. These are used alone or as a mixture of two or more. Examples of mono (meth) acrylate include mono (meth) acrylates of monoalcohol, mono (meth) acrylates of polyol, and the like.
  • the prism sheet 4 is described as including the transparent base material 43 and the prism portion 44.
  • the prism sheet 4 may be composed of a single material.
  • the prism sheet 4 can be made of a synthetic resin having a high light transmittance.
  • a synthetic resin include methacrylic resin, acrylic resin, polycarbonate resin, polyester resin, and salt resin resin.
  • methacrylic resin is optimal because of its high light transmittance, heat resistance, mechanical properties, and molding cacheability.
  • methacrylic resin is a resin containing methyl methacrylate as a main component, and methyl methacrylate is preferably 80% by weight or more.
  • FIG. 4 schematically shows how the prism sheet 4 deflects light in the XZ plane.
  • This figure shows an example of the traveling direction of peak light (light corresponding to the peak of the outgoing light distribution) from the light guide 3 in the XZ plane.
  • Most of the peak light obliquely emitted at an angle ⁇ from the light emitting surface 33 of the light guide 3 is incident on the first prism surface 41 la of the prism ⁇ Ij411 and is almost entirely in the inner surface by the second prism surface 411b.
  • the light is reflected and emitted in the direction of the normal of the light exit surface 42.
  • a part of the peak light is incident on the first prism surface 41 la of the prism IJ411, diffused by the roughening unit 412 and emitted from the light exit surface 42.
  • This light diffusion is also done in the YZ plane.
  • part of the light other than the peak light is directly incident on the roughened portion 412 and diffused. Based on such light diffusion in the roughened portion 412, an effect of concentrating the amount of light in a desired observation direction range and an excellent effect of improving luminance unevenness can be obtained.
  • the YZ plane there is the action of the prism row on the back surface 34 of the light guide as described above, so that the luminance in the normal direction of the light exit surface 42 can be sufficiently improved in a wide range.
  • the shape of the prism surfaces 41 la and 41 lb of the prism row 411 of the prism sheet 4 is not limited to a single flat surface, and can be, for example, a convex polygonal shape or a convex curved surface shape. Further, it is possible to further increase the brightness and narrow the visual field.
  • the desired prism array shape is accurately manufactured to obtain stable optical performance, and the purpose of suppressing wear and deformation of the top of the prism array during assembly work and use of the light source device
  • a top flat portion or a top curved surface portion may be formed at the top of the prism row.
  • the width of the top flat portion or the top curved surface portion should be 3 / m or less. It is preferable from the viewpoint of suppressing the occurrence of uneven brightness patterns due to sticking phenomenon as the brightness of the liquid crystal display device is reduced. More preferably, the width of the top flat portion or the top curved surface portion is 2 ⁇ m or less, and more preferably 1 ⁇ m or less.
  • the prism sheet 4 as described above is synthesized using a mold member having a shape transfer surface that transfers and forms a light incident surface 41 including a prism row forming surface having a prism row 411 and a roughened portion 412. Manufacturing power S can be achieved by shaping the surface of the resin sheet. The production of this mold part will be described with reference to FIG.
  • the first regions 411a ", 411b” having a shape corresponding to the prism surfaces 41la, 411b of the prism row 411 and the roughened portion 412 are substantially the same.
  • Corresponding shape A mold member 41 ′ having a shape transfer surface composed of the second region 412 ′′ is produced.
  • the shape of the second region 412 ′′ substantially corresponds to the roughened portion 412 ” will be described later.
  • the shape corresponding to the roughened portion 412 can be obtained by blasting.
  • the shape of the second region 412 can be a shape formed by extending the shape (for example, a plane) of the first region 41la", 41lb "as it is.
  • blasting is performed on the shape transfer surface of the mold member 41 ′, so that the second region 4 12 ′′ is roughened and has a shape corresponding to the roughened portion 412.
  • Such a blasting process is performed such that the blast particles are not substantially sprayed to the first regions 41 la ′′ and 411b ′′ of the mold member 41 ′ and are sprayed only to the second regions 412 ′′.
  • blasting is performed using blast particles having a size (particle size) that does not enter the depth of the recess of the mold member 41 ′.
  • blast particles BP within an appropriate particle size range should be used.
  • the prism apex angle ⁇ force is 3 ⁇ 40 to 75 degrees, it is preferable to use a particle having a particle diameter of 0.3 times pitch P or more.
  • the particle size of the blast particle BP is preferably about 5 times the pitch P at the maximum.
  • the particle size of the blast particle BP is more preferably 1 to 4 times the pitch P, and still more preferably 2 to 3 times the pitch P.
  • the blast pressure can be set as appropriate according to the material and particle size of the blast particles to be used, the material of the mold member 41 ′, etc. By performing the blasting process as described above for an appropriate time, it corresponds to the first regions 41 la ′ and 411b ′ having a shape corresponding to the prism row and the roughened portion as shown in FIG. A mold member 41 ′ having a shape transfer surface composed of the shape second region 412 ′ is obtained.
  • the direction of spraying of the blast particles BP can be made oblique.
  • blast particles having a small particle size in which the blast pressure is easily controlled, as compared with the case of FIG. 5 (b).
  • the width of the second region 412 ′ having a shape corresponding to the roughened portion can be appropriately set.
  • the prism surfaces 411a and 41 lb of the prism ⁇ Ij411 are optically sufficiently flat.
  • a smooth surface is shown, and the first region 41 la ", 41 lb" of the mold member 41 'has already been formed into a shape corresponding to the prism surfaces 411a, 41 lb before blasting. This area is almost unaffected by blasting.
  • the blast particles may include those having a flat shape, and the influence of the blast treatment may reach the first region 41 la ", 411b".
  • the first regions 411a "and 41 lb” are slightly roughened by blasting to form the first regions 41 la 'and 41 lb. That is, the prism surfaces 411a and 41 lb of the prism row 411 are slightly roughened to a roughening degree smaller than the surface of the roughened portion 412.
  • the prism surfaces 41 la and 411b of the prism array 411 may be intentionally roughened to a roughening degree smaller than the surface of the roughened portion 412.
  • the first regions 41 la "and 41 lb" of the mold member 41 ' are formed in a shape substantially corresponding to the prism surfaces 41 la and 41 lb before blasting.
  • the shape "corresponds substantially to the prism surfaces 41 la, 411b” means that the shape corresponding to the prism surfaces 41 la, 41 lb is obtained by blasting. It refers to such a shape.
  • the second blasting process for spraying blasting particles having a smaller particle size is performed.
  • the first region 41 la “, 411b” is roughened, and the shape corresponding to the prism surfaces 41 la, 41 lb of the prism array 411 is formed, and the second region 412 "is roughened by the roughened portion 412. It becomes the shape corresponding to.
  • the particle size of the blast particles used for the second blasting process can be, for example, 0.1 to 0.5 times the arrangement pitch P of the prism rows.
  • a prism sheet can be obtained by performing synthetic resin molding using the mold member produced as described above and the mold member having a planar shape transfer surface. That is, by using the mold member produced as described above and shaping the surface of the synthetic resin sheet, a prism sheet having a required prism array forming surface can be obtained.
  • the surface of the synthetic resin sheet can be shaped by hot pressing, extrusion molding, injection molding or the like.
  • FIG. 6 is a schematic view showing another embodiment of shaping a synthetic resin sheet.
  • reference numeral 7 denotes a mold member (roll mold) in which a shape transfer surface equivalent to the mold member 41 ′ is formed on a cylindrical outer peripheral surface.
  • This roll type 7 is made of metal such as anorium, brass, steel, etc. It can be powerful.
  • FIG. 7 is a schematic perspective view of the roll mold 7.
  • a shape transfer surface 18 is formed on the outer peripheral surface of the cylindrical tool 16. The blasting process as described above for forming the shape transfer surface 18 can be performed with high accuracy and good productivity while rotating the roll mold.
  • FIG. 8 is a schematic exploded perspective view showing a modified example of the roll mold 7. In this modification, a thin plate-shaped mold member 15 is wound around and fixed to the outer peripheral surface of the cylindrical roll 16.
  • the thin plate-shaped mold member 15 is equivalent to the mold member 41 ′, and a shape transfer surface is formed on the outer surface.
  • the blasting process as described above for forming the shape transfer surface can be performed on the flat thin plate-shaped mold member 15, but the mold member 15 is wound around and fixed to the outer peripheral surface of the cylindrical roll 16. It can be performed with high accuracy by rotating the roll mold after forming the roll mold.
  • a transparent substrate 9 is supplied along the outer peripheral surface, that is, the shape transfer surface, to the Ronole mold 7, and the mold 7 and the transparent substrate 9
  • the active energy ray-curable composition 10 is continuously supplied from the resin tank 12 through the nozzle 13.
  • an ep roll 28 for making the thickness of the supplied active energy ray-curable composition 10 uniform is installed on the outside of the transparent substrate 9.
  • a metal roll, a rubber roll or the like is used.
  • the nip roll 28 is required to accurately adjust the thickness of the active energy ray-curable composition 10 and is operated by the pressure mechanism 11.
  • a hydraulic cylinder, a pneumatic cylinder, various screw mechanisms, and the like can be used, but a pneumatic cylinder is preferable from the viewpoint of simplicity of the mechanism.
  • the air pressure is controlled by a pressure regulating valve.
  • the active energy ray-curable composition 10 supplied between the roll mold 7 and the transparent substrate 9 is preferably maintained at a constant viscosity in order to keep the thickness of the obtained prism portion constant. Ms.
  • the viscosity range is preferably in the range of 20 to 3000 mPa ′ S, and more preferably in the range of 100 to 1000 mPa ′ S.
  • the viscosity of the active energy ray-curable composition 10 to 20 mPa 'S or more.
  • the pressure mechanism 11 tends to be unable to operate stably, and the thickness of the prism portion becomes unstable. Further, when the molding speed is extremely increased, the irradiation amount of the active energy line is insufficient, and the active energy ray-curable composition tends to be insufficiently cured.
  • the curable composition 10 can be sufficiently distributed to the details of the roll-shaped shape transfer surface structure, and the lens shape can be accurately determined. Transfer is difficult, defects due to air bubbles are likely to occur, and productivity is not deteriorated due to an extremely low molding speed.
  • a sheathed heater, a hot water jacket, etc. are provided outside or inside the resin tank 12 so that the temperature of the curable composition 10 can be controlled. It is preferable to install a heat source facility.
  • the active energy ray-curable composition 10 After supplying the active energy ray-curable composition 10 between the roll mold 7 and the transparent substrate 9, the active energy ray-curable composition 10 is formed between the mouth mold 7 and the transparent substrate 9.
  • the active energy ray irradiating device 14 irradiates the active energy ray through the transparent base material 9 to polymerize and cure the active energy ray curable composition 10, and the shape transfer formed on the roll mold 7 Transfer the surface.
  • a chemical reaction chemical lamp, a low-pressure mercury lamp, a high-pressure mercury lamp, a metal halide lamp, a visible light halogen lamp, or the like is used as the active energy ray irradiation device 14.
  • the irradiation amount of the active energy ray is preferably such that the integrated energy of the wavelength of 200 to 600 nm is 0.:! To 50 j / cm 2 .
  • the irradiation atmosphere of active energy rays may be air or an inert gas atmosphere such as nitrogen or argon.
  • the present invention includes the surface light source device including the primary light source 1, the light source reflector 2, the light guide 3, and the light reflecting element 5 as described above, and the transmissive liquid crystal display element 8 with the prism sheet 4.
  • a liquid crystal display device is constructed.
  • the liquid crystal display device is observed by an upward force observer in FIG. 1 or FIG. [0064]
  • the prism sheet 4 since the prism sheet 4 has the above-described characteristics, the luminance unevenness in the liquid crystal display device is improved, and the force is less reduced in luminance.
  • the prism sheet 4 has a mirror surface or a rough surface with a small degree of roughening formed at the top and the vicinity of the prism row 411 that greatly contributes to the light deflection function.
  • the rough surface 412 having a large surface roughness is formed in the portion between adjacent prism rows that contributes little to the The concealment function can also be exhibited well.
  • FIG. 11 is a schematic partial enlarged cross-sectional view of one embodiment of a prism sheet constituting the liquid crystal display element with a prism sheet according to the present invention
  • FIG. 12 is a schematic partial enlarged bottom view thereof.
  • members or portions having the same functions as in FIGS. 1 to 8 are given the same reference numerals.
  • the light incident surface 41 which is the prism row forming surface, extends the plurality of prisms IJ411 in parallel to each other in the Y direction. In the point formed by arranging, it is the same as that of the said embodiment.
  • the prism row forming surface 41 has a trough portion 412A extending in the Y direction between adjacent prisms 1J411.
  • the width WA of the valley 412A is preferably 0.04 times to 0.5 times the arrangement pitch P of the prism rows 411, similarly to the width W of the roughened portion 412 of the above embodiment. It is more preferable that the ratio is 08 times to 0.3 times. It is particularly preferable that the ratio is 0.1 times to 0.2 times.
  • the ridge line of the prism row 411 is indicated by reference numeral 413.
  • the trough portion 412A has an irregular cross-sectional shape.
  • the irregularity is taken for each prism array arrangement pitch P in both the extending direction (Y direction) and the array direction (X direction) of the prism array 411 within an area (domain) of a predetermined size.
  • the predetermined size of the region may be 500 zm for each of the Y direction and the X direction. If the arrangement pitch P of the prism array 411 is 100 zm, as shown in FIG. 12, the valley 412A existing in each of the X-direction coordinates xl to x5 has a prism array array pin in the X direction. It is arranged continuously for every P.
  • valleys 412A For each of these five continuously arranged valleys 412A, on each surface of the Y-direction coordinates yl to y5 separated by the prism array arrangement pitch P. Take 5 cut sections. That is, in total, 25 cross-sectional shapes with XY coordinates from (xl, yl) to (x5, y5) are taken.
  • the valley cross-sectional shape is irregular. That is.
  • the fact that the cross-sectional shapes of the valleys are different means that the differences in the optical functions for reflecting or refracting the incoming light from the light guide 3 as described with reference to FIG. 4 are significant.
  • the cross-sectional shapes of the valleys are different means that the shape and optical function are not identical.
  • Figure 13 shows the XZ cross-sectional shape of the valley 412A. In FIG. 13, (a) and (b) show different valley cross-sectional shapes.
  • the trough 412A having an irregular cross-sectional shape as described above is blasted with blast particles having an average particle diameter of 0.3 to 5 times the prism row arrangement pitch as described in the above embodiment.
  • a forming member can be formed by shaping the surface of the synthetic resin sheet using a mold member having a shaped transfer surface. 11 to 13 do not mention the fine structure of the valley 412A, but the valley 412A is as described in the above embodiment. It has a fine structure of surface roughness.
  • the prism array forming surface 41 of the prism sheet is used.
  • the valley 412A having an irregular cross-sectional shape
  • the incoming light of the light guide force is irregularly diffused or reflected, so that it is difficult to visually recognize the surface structure of the light guide.
  • the prism sheet 4 has a mirror surface or a rough surface with a small degree of roughness formed on the top and the vicinity of the prism row 411 that greatly contributes to the light deflection function.
  • the trough 412A having an irregular cross-sectional shape is formed in the portion between adjacent prism rows that has a small contribution to the surface, so that the surface structure of the light guide can be visually confirmed while performing the required light deflection function satisfactorily.
  • the function of concealing optical defects can also be exhibited well.
  • a simple means of making only the cross-sectional shape of the valley portion irregular while maintaining the cross-sectional shape of the prism row, that is, adding blasting to the mold member on the manufacturing surface By simple means, it is possible to conceal optical defects that cause luminance unevenness due to the structure of a light guide or the like that does not cause a decrease in luminance and causes speckles at low cost.
  • FIG. 14 is a schematic partially cutaway perspective view showing one embodiment of a liquid crystal display device using a liquid crystal display element with a prism sheet according to the present invention.
  • members or portions having the same functions as those in FIGS. 1 to 8 and 11 to 13 are denoted by the same reference numerals.
  • a point light source such as a light emitting diode (LED) is used as the primary light source 1.
  • LED light emitting diode
  • One corner of the rectangular plate-shaped light guide 3 is cut out, and a light incident end face 31 is formed here.
  • the primary light source 1 is disposed so as to face the light incident end face.
  • a light emitting mechanism is formed as in the above embodiment.
  • the prism rows 411 formed on the light incident surface 41 of the prism sheet 4 are arranged in parallel concentrically around the corner where the light incident end surface 31 of the light guide 3 is formed. ing. In this specification, the arrangement of such a plurality of prism rows is also substantially parallel to each other.
  • the light emitted from the primary light source 1 is a divergent light beam in the plane parallel to the light emitting surface 33 and is incident on the light incident end surface 31 and introduced into the light guide 3. The emitted light travels substantially radially about the primary light source 1 and is also emitted substantially radially when exiting from the light exit surface 33.
  • the prism rows 411 on the light incident surface of the prism sheet 4 are concentrically arranged as described above, the light incident on the light incident surface 41 and introduced into the prism sheet 4 is described in the above embodiment. Similarly, the light is deflected in a substantially normal direction of the light guide light emitting surface 33 and emitted from the light emitting surface 42. Also in the present embodiment, irregularly shaped valleys 412A are formed between adjacent ones of the plurality of prisms IJ411 formed on the light incident surface 41 of the prism sheet 4.
  • the behavior of light when viewed in a cross-section (cross-section passing through the primary light source) orthogonal to the extending direction of the prism ridge 11 (direction of tangent at each position of the arc) is the above-described embodiment.
  • This is similar to the behavior of light when viewed in a cross section (XZ cross section) perpendicular to the extending direction of the prism row 411. Accordingly, the dimensional relationship between the prism IJ411 and the valley 412A is the same as that of the above embodiment when viewed from these cross sections.
  • the bonding of the prism sheet 4 and the liquid crystal display element 8 by the bonding material 86 is performed over the entire facing surface.
  • This bonding may be performed on a part of the opposing surface of the prism sheet 4 and the liquid crystal display element 8.
  • a method other than bonding using a bonding material may be used for bonding the prism sheet 4 and the liquid crystal display element 8.
  • An example of such a method is holding the pressure at the peripheral portion by the mechanical pressure means.
  • a shape transfer surface with a shape almost corresponding to the shape of the prism array formation surface as described with reference to Fig. 5 (a) is formed on the surface of three types of thin plates with a thickness of 1 Omm, 400 mm X 690 mm. It was.
  • the shape of the second region 412 "of the shape transfer surface of the mold member shown in Fig. 5 (a) corresponds to an extension of the planar shape of the first regions 411a" and 41 lb ". It is.
  • blasting is performed by spraying with blast particles made of glass beads having a center particle diameter of 45 to 75 xm at a nozzle discharge pressure of 0.07 MPa.
  • the shape of the second region 412 ′ as described with respect to (b) was formed.
  • the roughness of the second region was a center line average roughness Ra of 0.5 111 and a 10-point average roughness of 1 ⁇ of 1.5 ⁇ m. Further, the roughness of the first region was such that the center line average roughness Ra was 0 .: m and the 10-point average roughness Rz was 0.
  • the shape transfer surface of the mold member obtained as described above was subjected to electroless nickel plating.
  • a stainless steel cylindrical roll having a diameter of 220 mm and a length of 450 mm as shown in FIG. 8 is prepared, and the mold member 15 is wound around the outer peripheral surface thereof with a screw. Fixed to obtain a roll type.
  • an NBR rubber roll 28 having a rubber hardness of 80 ° was disposed so as to be close to the roll mold 7.
  • the polyester film 9 was nipped between the rubber roll 28 and the roll mold 7 by the pneumatic cylinder 11.
  • the operating pressure of the pneumatic cylinder 11 at this time was 0. IMP a.
  • an SMC air cylinder with an air tube diameter of 32 mm was used.
  • an ultraviolet irradiation device 14 was installed below the roll mold 7.
  • the ultraviolet irradiation device 14 has an ultraviolet intensity of 120 W / cm, a capacity of 9.6 kW, a UV irradiation lamp manufactured by Western Quart, a cold mirror type parallel light reflector and a power source.
  • the ultraviolet curable composition 10 was mixed with a refractive index adjusting component, a catalyst, and the like in advance, and charged into the resin tank 12.
  • the resin tank 12 was made of SUS304 at all the portions in contact with the ultraviolet curable composition 10.
  • it has a hot water jacket layer for controlling the liquid temperature of the ultraviolet curable composition 10, and hot water adjusted to 40 ° C by a temperature controller is supplied to the hot water jacket layer, and the resin tank 12
  • the liquid temperature of the UV curable composition 10 is 40. C ⁇ 1. C was held.
  • the resin tank 12 is evacuated by a vacuum pump. Thus, bubbles generated at the time of charging were removed.
  • the ultraviolet curable composition 10 was as follows, and the viscosity was adjusted to 300 mPa'S / 25 ° C.
  • Bisphenol A-diepoxy monoacrylate (Epoxy Cisternol 3000A manufactured by Kyoeisha Yushi Chemical Co., Ltd.): 50 parts by weight
  • the UV curable composition 10 becomes the roll mold 7 and the polyester film 9
  • the ultraviolet ray irradiation device 14 was irradiated with ultraviolet rays to polymerize and cure the ultraviolet curable composition 10 to transfer the prism row pattern on the shape transfer surface of the roll mold 7. Thereafter, it was released from the roll mold 7 to obtain a prism sheet.
  • the prism row forming surface is directed downward on the light emission surface of the acrylic resin light guide having the cold cathode tube arranged on the side surface.
  • the other side surface and back surface were covered with a reflection sheet, and a surface light source for a 14.1-inch liquid crystal display device was obtained.
  • this surface light source the cold cathode tube was turned on and the light emitting surface (light emitting surface of the prism sheet) was observed. As a result, the brightness unevenness is not visually recognized, and it is optically concealed. It was excellent.
  • the cold-cathode tube was turned on to measure the luminance distribution (distribution in the XZ plane and distribution in the YZ plane) of the light emitting surface.
  • the results are shown in Figs.
  • the peak luminance value was 2534 cd / m 2
  • the peak angle was -3.7 degrees
  • the half width was 21 degrees.
  • the peak luminance value was 2377 cd / m 2
  • the peak angle was ⁇ 3.0 degrees
  • the half-value width was 41 degrees.
  • the above prism is formed using a soft silicon resin (rubber) as a bonding material.
  • the light-emitting surface of the sheet was joined.
  • a liquid crystal display element with a prism sheet was formed, and a liquid crystal display device was obtained.
  • the cold cathode tube was turned on and the liquid crystal display element was driven, and the white screen displayed on the liquid crystal display element was observed.
  • the luminance unevenness was not visually recognized and was excellent in optical concealment.
  • a prism sheet was obtained by performing the same process as in Example 1 except that the nozzle discharge pressure was set to 0 ⁇ 15 MPa in the blasting process on the shape transfer surface of the mold member.
  • the center line average roughness Ra was 0.8 ⁇ and the ten-point average roughness Rz was 2.6 ⁇ .
  • the roughness of the first region was such that the center line average roughness Ra was 0.1111 and the ten-point average roughness 13 ⁇ 4 was 0.5 / im.
  • the width of the roughened portion was 30 ⁇ . Using this prism sheet, a surface light source was obtained in the same manner as in Example 1.
  • the cold cathode tube was turned on in the same manner as in Example 1 to observe the light emitting surface. As a result, the luminance unevenness was not visually recognized, and the optical concealment was excellent.
  • the cold cathode tube was turned on and the luminance distribution (distribution in the XZ plane and distribution in the YZ plane) of the light emitting surface was measured. The results are shown in Figs.
  • the peak luminance value was 2207 cd / m 2
  • the peak angle was 9.1 degrees
  • the half-value width was 20.5 degrees.
  • the peak luminance value was 1466 cd / m 2
  • the peak angle was -4 degrees
  • the half width was 42 degrees.
  • Example 2 the light emitting surface of the prism sheet was bonded to the light incident side surface of the liquid crystal display element.
  • a liquid crystal display element with a prism sheet was formed, and a liquid crystal display device was obtained.
  • the cold cathode tube is turned on and the liquid crystal display element is driven, thereby the liquid crystal display element
  • the white screen displayed on the screen was observed. As a result, the luminance unevenness was not visually recognized and was excellent in optical concealment.
  • a prism sheet was obtained by carrying out the same steps as in Example 1 except that the blast treatment was performed as follows. That is, in the blasting process for the shape transfer surface of the mold member, after performing the first blasting process using a blast particle made of glass beads having a central particle diameter of 45 to 75 ⁇ m and spraying at a nozzle discharge pressure of 0.07 MPa, A second blasting process was performed using blast particles made of glass beads with a central particle size of 10 ⁇ m and sprayed at a nozzle discharge pressure of 0. IMPa. The roughness of the second region of the die member after blasting was 0.6111 for the center line average roughness Ra and 1 for the 10-point average roughness 1 ⁇ .
  • the center line average roughness Ra was 0.3111 and the ten-point average roughness 13 ⁇ 4 was 0.
  • the width of the roughened portion was 23 ⁇ m.
  • Example 2 the light emitting surface of the prism sheet was bonded to the light incident side surface of the liquid crystal display element.
  • a liquid crystal display element with a prism sheet was formed, and a liquid crystal display device was obtained.
  • the cold cathode tube was turned on and the liquid crystal display element was driven, and the white screen displayed on the liquid crystal display element was observed.
  • the luminance unevenness was not visually recognized and was excellent in optical concealment.
  • a liquid crystal display device with a prism sheet was formed in the same manner as in Example 1 except that the light exit surface of the prism sheet was bonded using silicon resin (rubber) to obtain a liquid crystal display device.
  • a white LED is turned on and a liquid crystal display element is driven, and the liquid crystal display element The white screen displayed on the screen was observed. As a result, the luminance unevenness was not visually recognized and was excellent in optical concealment.
  • a prism sheet was obtained by performing the same process as in Example 1 except that the blasting treatment for the shape transfer surface of the mold member was not performed.
  • the center line average roughness Ra and the ten-point average roughness Rz of the prism row of the obtained prism sheet are the center line average roughness Ra of 0.16 zm and the ten-point average roughness Rz at the top of the prism row.
  • the center line average roughness Ra on the prism surface was 0.05 05 111 and the 10-point average roughness 1 ⁇ was 0.
  • the width of the roughened portion was 0 zm, that is, there was no roughened portion.
  • a surface light source was obtained in the same manner as in Example 1.
  • the cold cathode tube was turned on in the same manner as in Example 1 and the light emitting surface was observed.
  • uneven brightness due to defective form of the prism sheet based on defects in the mold for manufacturing the prism sheet and adhesion residue of the protective sheet adhesive on the prism row after the adhesive protective sheet is peeled off due to the application of the adhesive protective sheet.
  • the cold cathode tube was turned on and the luminance distribution (distribution in the XZ plane and distribution in the YZ plane) was measured. The results are shown in FIG. 9 and FIG.
  • the peak luminance value was 2631 cd / m 2
  • the peak angle was ⁇ 2.5 degrees
  • the half-value width was 20 degrees.
  • the peak luminance value was 2436 cd / m 2
  • the peak angle was ⁇ 2 degrees
  • the half-value width was 40 degrees.
  • Example 2 the light emitting surface of the prism sheet was bonded to the light incident side surface of the liquid crystal display element.
  • a liquid crystal display element with a prism sheet was formed, and a liquid crystal display device was obtained.
  • the cold cathode tube was turned on and the liquid crystal display element was driven, and the white screen displayed on the liquid crystal display element was observed. As a result, uneven brightness was visually recognized and the optical concealment was not sufficient.
  • a mold member was produced by an apparatus as shown in FIG.
  • a surface of a cylindrical metal roll having a diameter F "of 230 mm and a length B of 500 mm is subjected to a copper plating (not shown) having a thickness of 0.5 mm, and then the copper plating surface is smoothed.
  • Processing and copper plating part A prism shape C with an apex angle of 68 degrees and an array pitch of 50 ⁇ m was continuously formed by cutting with a cutting tool.
  • an electroless nickel plating film (not shown) was formed with a thickness of 1 ⁇ m, and a mold member blank A in which the prism shape was continuously formed was produced.
  • FIG. 16 shows an enlarged cross-sectional photograph of the prism row of this mold member blank A and the transfer surface portion of the trough. The shapes of the transfer surfaces of the prism rows and the valleys were substantially the same for adjacent repeating units.
  • the mold member blank A was subjected to a blasting treatment as follows. That is, the mold member blank A was mounted on a device (not shown) that can rotate the mold member blank A installed in the blast box continuously or discontinuously in the circumferential direction.
  • the air blasting device AMD-10 type manufactured by Niche Yu Co., Ltd. was used as the blasting device, and glass beads [trade name J-120] manufactured by Potters Valorutini Co., Ltd. were used as the polishing material.
  • Nozzle D with a tip diameter of 2 mm was used, the discharge pressure was 0. IMPa, and the distance E between the tip of Nozno D and the surface of the die blank A was 450 mm.
  • the movement of the nozzle D during blasting is done by setting the distances F and F 'to 100 mm each in order to suppress the occurrence of spraying irregularities at the start and end of discharge in addition to the effective area B of the mold blank A.
  • the total travel distance was 700 mm.
  • Blasting is performed while moving the nozzle D at a constant speed of 5m / min to D 'in the direction perpendicular to the cutting direction of the prism row transfer surface formed on the mold blank A (K-K' direction). Carried out.
  • the mold part blank A was rotated in the circumferential direction of the mold part blank A by a circumference of 20 mm (angle of about 10 degrees), and blasting was performed in the K—K ′ direction by the same operation as described above.
  • blasting was performed on all parts, that is, the entire outer peripheral surface of the mold member blank A.
  • FIG. 17 shows an enlarged cross-sectional photograph of the prism row and the trough transfer surface portion of the mold member obtained as described above.
  • the shape of the trough transfer surface (bottom edge in the figure) was substantially different for all adjacent repeat units.
  • a prism sheet was obtained in the same manner as in Example 1.
  • a surface light source was obtained in the same manner as in Example 1 using the obtained prism sheet.
  • the surface structure of the light guide and prism sheet is visible. Further, luminance unevenness was not visually recognized, and it was excellent in concealing optical defects.
  • Example 2 the light emitting surface of the prism sheet was bonded to the light incident side surface of the liquid crystal display element.
  • a liquid crystal display element with a prism sheet was formed, and a liquid crystal display device was obtained.
  • the cold cathode tube was turned on and the liquid crystal display element was driven, and the white screen displayed on the liquid crystal display element was observed.
  • the luminance unevenness was not visually recognized and was excellent in optical concealment.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Nonlinear Science (AREA)
  • Mathematical Physics (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Optical Elements Other Than Lenses (AREA)
  • Devices For Indicating Variable Information By Combining Individual Elements (AREA)
  • Liquid Crystal (AREA)

Abstract

Une surface émettant de la lumière (42) d'une feuille prismatique (4) est collée sur un côté d'entrée de la lumière d'un élément d'affichage à cristaux liquides (8) par une substance adhésive (86). Une surface d'entrée de la lumière (41) de la feuille prismatique (4) est utilisée en tant que surface formant des rangées de prismes. La surface formant des rangées de prismes (41) est formée en disposant une pluralité de rangées de prismes pour s'étendre pratiquement parallèlement les unes par rapport aux autres. La surface formant des rangées de prismes (41) comporte une section rugueuse qui s'étend le long des rangées de prismes entre les rangées de prismes adjacentes. La surface de la section rugueuse est plus rugueuse que la surface de prismes de la rangée de prismes. La lumière émise à partir d'une source lumineuse principale (1) est introduite dans un corps conducteur de lumière (3) à travers une surface d'extrémité d'entrée de la lumière (31). La lumière conduite dans le corps conducteur de lumière (3) est délivrée à partir d'une surface de sortie de la lumière (33) et son entrée dans la surface d'entrée de la lumière (41) de la feuille prismatique (4) est permise.
PCT/JP2007/059180 2006-05-02 2007-04-27 Élément d'affichage à cristaux liquides comportant une feuille prismatique, et dispositif d'affichage à cristaux liquides utilisant l'élément d'affichage à cristaux liquides WO2007129609A1 (fr)

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010237398A (ja) * 2009-03-31 2010-10-21 Kimoto & Co Ltd プリズムシート及びこれを用いたバックライト
JP2011247947A (ja) * 2010-05-24 2011-12-08 Dainippon Printing Co Ltd 光学シート、面光源装置、表示装置
TWI498602B (zh) * 2008-07-29 2015-09-01 李大煥 光學板片及其製造方法
WO2016076426A1 (fr) * 2014-11-14 2016-05-19 富士フイルム株式会社 Dispositif d'affichage à cristaux liquides
WO2016076439A1 (fr) * 2014-11-14 2016-05-19 富士フイルム株式会社 Dispositif d'affichage à cristaux liquides
JP2019044183A (ja) * 2017-09-04 2019-03-22 荒川化学工業株式会社 保護フィルム用紫外線硬化型粘着剤組成物、粘着剤層、保護シート

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP6798372B2 (ja) * 2017-03-14 2020-12-09 オムロン株式会社 導光体、表示装置及び遊技機

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Publication number Priority date Publication date Assignee Title
JPH06148408A (ja) * 1992-11-11 1994-05-27 Sekisui Chem Co Ltd 光制御シート
JPH06250182A (ja) * 1993-03-01 1994-09-09 Enplas Corp 面光源装置用プリズムシート
JP2004200072A (ja) * 2002-12-19 2004-07-15 Minebea Co Ltd 面状照明装置
JP2005142164A (ja) * 2003-11-08 2005-06-02 Samsung Electronics Co Ltd 導光板及びこれを有するバックライトアセンブリ
WO2007046337A1 (fr) * 2005-10-17 2007-04-26 Mitsubishi Rayon Co., Ltd. Feuille prismatique et son procédé de production et dispositif à source de lumière en surface

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH06148408A (ja) * 1992-11-11 1994-05-27 Sekisui Chem Co Ltd 光制御シート
JPH06250182A (ja) * 1993-03-01 1994-09-09 Enplas Corp 面光源装置用プリズムシート
JP2004200072A (ja) * 2002-12-19 2004-07-15 Minebea Co Ltd 面状照明装置
JP2005142164A (ja) * 2003-11-08 2005-06-02 Samsung Electronics Co Ltd 導光板及びこれを有するバックライトアセンブリ
WO2007046337A1 (fr) * 2005-10-17 2007-04-26 Mitsubishi Rayon Co., Ltd. Feuille prismatique et son procédé de production et dispositif à source de lumière en surface

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
TWI498602B (zh) * 2008-07-29 2015-09-01 李大煥 光學板片及其製造方法
JP2010237398A (ja) * 2009-03-31 2010-10-21 Kimoto & Co Ltd プリズムシート及びこれを用いたバックライト
JP2011247947A (ja) * 2010-05-24 2011-12-08 Dainippon Printing Co Ltd 光学シート、面光源装置、表示装置
WO2016076426A1 (fr) * 2014-11-14 2016-05-19 富士フイルム株式会社 Dispositif d'affichage à cristaux liquides
WO2016076439A1 (fr) * 2014-11-14 2016-05-19 富士フイルム株式会社 Dispositif d'affichage à cristaux liquides
JPWO2016076426A1 (ja) * 2014-11-14 2017-07-20 富士フイルム株式会社 液晶表示装置
JP2019044183A (ja) * 2017-09-04 2019-03-22 荒川化学工業株式会社 保護フィルム用紫外線硬化型粘着剤組成物、粘着剤層、保護シート

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JPWO2007129609A1 (ja) 2009-09-17

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