WO2006115113A1 - Optical member, planar illuminating device, and liquid crystal display - Google Patents

Optical member, planar illuminating device, and liquid crystal display Download PDF

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Publication number
WO2006115113A1
WO2006115113A1 PCT/JP2006/308101 JP2006308101W WO2006115113A1 WO 2006115113 A1 WO2006115113 A1 WO 2006115113A1 JP 2006308101 W JP2006308101 W JP 2006308101W WO 2006115113 A1 WO2006115113 A1 WO 2006115113A1
Authority
WO
WIPO (PCT)
Prior art keywords
light
guide plate
light guide
transmittance
transmittance adjusting
Prior art date
Application number
PCT/JP2006/308101
Other languages
French (fr)
Japanese (ja)
Inventor
Shin Soejima
Akihiko Takeda
Original Assignee
Fujifilm Corporation
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 Fujifilm Corporation filed Critical Fujifilm Corporation
Publication of WO2006115113A1 publication Critical patent/WO2006115113A1/en

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Classifications

    • 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
    • G02B6/0021—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 for housing at least a part of the light source, e.g. by forming holes or recesses
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/02—Diffusing elements; Afocal elements
    • G02B5/0205—Diffusing elements; Afocal elements characterised by the diffusing properties
    • G02B5/0236—Diffusing elements; Afocal elements characterised by the diffusing properties the diffusion taking place within the volume of the element
    • G02B5/0242—Diffusing elements; Afocal elements characterised by the diffusing properties the diffusion taking place within the volume of the element by means of dispersed particles
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/02—Diffusing elements; Afocal elements
    • G02B5/0273—Diffusing elements; Afocal elements characterized by the use
    • G02B5/0278—Diffusing elements; Afocal elements characterized by the use used in transmission
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/02—Diffusing elements; Afocal elements
    • G02B5/0273—Diffusing elements; Afocal elements characterized by the use
    • G02B5/0284—Diffusing elements; Afocal elements characterized by the use used in reflection
    • 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
    • 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
    • G02B6/0045—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 by shaping at least a portion of the light guide
    • G02B6/0046—Tapered light guide, e.g. wedge-shaped light guide
    • 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
    • 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
    • G02B6/0051—Diffusing 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
    • G02B6/0033—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
    • G02B6/0033—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
    • G02B6/0055—Reflecting 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
    • G02B6/0066—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 characterised by the light source being coupled to the light guide
    • G02B6/0068—Arrangements of plural sources, e.g. multi-colour light sources
    • 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
    • G02B6/0066—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 characterised by the light source being coupled to the light guide
    • G02B6/007—Incandescent lamp or gas discharge lamp
    • G02B6/0071—Incandescent lamp or gas discharge lamp with elongated shape, e.g. tube
    • 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
    • G02F1/133611—Direct backlight including means for improving the brightness uniformity

Definitions

  • the present invention relates to an optical member that makes light emitted from a light exit surface of a light guide plate more uniform outgoing light, a planar illumination device using the same, and a liquid crystal display device.
  • a liquid crystal display device uses a backlight unit that illuminates the liquid crystal panel by irradiating the back side of the liquid crystal panel (LCD).
  • the backlight unit uses components such as a light source for illumination, a light guide plate that diffuses the emitted light and irradiates the liquid crystal panel, and a prism sheet and a diffusion sheet that uniformize the light emitted from the light guide plate.
  • a light source for illumination e.g., a light guide plate that diffuses the emitted light and irradiates the liquid crystal panel
  • a prism sheet and a diffusion sheet that uniformize the light emitted from the light guide plate.
  • JP-A-9-304623 discloses a surface light source device using a light guide plate.
  • FIG. 14 is an exploded perspective view of the surface light source device described in JP-A-9-304623.
  • the surface light source device backlight unit
  • the reflection sheet 104 is disposed on the back surface of the light guide plate 100, and the transmitted light amount is corrected on the light exit surface of the light guide plate 100. It is formed by laminating a sheet 106, a light diffusion plate 108, and a prism sheet 110.
  • the light guide plate 100 has a substantially rectangular shape and is formed of a resin in which fine particles that diffuse illumination light are dispersed and mixed. Further, the upper surface of the light guide plate 100 is flat, and is assigned as a light exit surface. Further, a U-shaped groove 100a for embedding the fluorescent lamp 102 is formed on the back surface of the light guide plate 100 (the surface opposite to the light emitting surface). The light emitting surface of the light guide plate 100 has a true shape of the fluorescent lamp 102. A light amount correction surface 100b that avoids the top and promotes the emission of illumination light is formed.
  • JP-A-9-304623 discloses that a light guide plate 100 is formed by mixing fine particles, The light intensity correction surface 100b formed on part or all of the light exit surface except directly above the fluorescent lamp 102 encourages the emission of illumination light, thereby reducing the overall thickness and unnatural brightness of the emitted light. It is described that unevenness can be reduced (see FIG. 15).
  • Japanese Patent Application Laid-Open No. 8-62426 discloses a liquid crystal display that can reduce the size and weight of a liquid crystal display device and reduce the power consumption without reducing the amount of knocklight irradiation.
  • a rectangular irradiation surface, a rectangular cross section grooved in parallel to the long side at the center of the short side, and a long section across the groove are inserted.
  • a light guide plate having a back surface formed so that the plate thickness gradually decreases toward both side surfaces of the side.
  • Japanese Patent Application Laid-Open No. 10-133027 discloses a liquid crystal display device in which the frame can be narrowed, the thickness can be reduced, and a light source can be arranged in order to obtain a bright backlight unit with high light utilization efficiency.
  • a light guide (light guide plate) is described in which the shape of the cross section parallel to the width direction of the recess is a parabolic shape with the depth direction as the main axis.
  • Japanese Patent Application Laid-Open No. 5-127156 describes that a printing portion on a dod for preventing light transmission is formed on the surface of a diffusion plate. Further, the density of the printed portion is made dense in the region where the cold cathode fluorescent lamp is located immediately below, and the amount of light emitted to the diffusion plate side is reduced over the entire surface of the diffusion plate by making the printing area sparse as the area force is moved away. It is written that it will be uniform.
  • Japanese Patent Laid-Open No. 6-235825 describes a light guide plate in which a light scattering layer is formed on the lower surface of a plate so that the area ratio increases as the linear light source force increases. It is described that the light scattering layer is used for extracting light inside the plate of the light guide plate from the upper surface in accordance with the luminance change from the line light source.
  • Japanese Patent Application Laid-Open Publication No. 2001-42327 is a strip that follows the longitudinal direction of the transparent substrate so as to suppress an increase in luminance due to direct light by being inversely proportional to the light source amount of the linear light source,
  • a transmission adjusting means is described which forms a density-modulated dot pattern printed with highly reflective ink.
  • the density modulation pattern of the dots is obtained by reducing the dot area or the number of dots in the in-plane direction from the edge of the protruding edge.
  • the light source light of the linear light source reaches the transmission adjusting means formed on the light emitting surface of the surface through each protruding edge, and the amount of transmission and the amount of transmission prevention are reduced by the density modulation.
  • Edge side force Adjust to increase gradually in the in-plane direction suppress the increase in brightness of the part where the linear light source is placed due to direct light source light, and uniformity with the light guide illumination brightness by the light guide means It is stated that it is secured.
  • Japanese Patent Application Laid-Open No. 2004-170698 discloses a liquid crystal display on which a luminance distribution inversion image formed by reversing gradation of data obtained by measuring at least the luminance distribution of the light exit surface of a backlight unit is printed.
  • a light diffusion sheet which is an optical member used in the backlight unit of the apparatus is described.
  • This inverted luminance distribution image has a high-precision gradation pattern that reflects the luminance distribution on the light exit surface of the knocklight unit, so that the light emitted from the light guide plate is not uneven in brightness after passing through the light diffusion sheet. It is described that the number of emission lines is reduced and generation of bright lines is prevented.
  • Patent Document 1 Japanese Patent Laid-Open No. 9 304623
  • Patent Document 2 JP-A-8-62426
  • Patent Document 3 JP-A-10-133027
  • Patent Document 4 JP-A-5-127156
  • Patent Document 5 JP-A-6-235825
  • Patent Document 6 Japanese Patent Laid-Open No. 2001-42327
  • Patent Document 7 Japanese Unexamined Patent Application Publication No. 2004-170698
  • the present invention has been made in view of the strong situation, and provides an optical member that can improve unevenness of luminance distribution, a planar illumination device using the same, and a liquid crystal display device. Objective.
  • a transmittance adjusting member in which a plurality of transmittance adjusting bodies for adjusting the transmittance of light are arranged on the surface of the optical member, and light is diffused.
  • An optical member formed by laminating a diffusion film that is uniformized in an optical manner, wherein the maximum dimension of the transmittance adjusting body is 500 m or less, and the viewing half-value angle of the diffusion film is 2.5 ° or more. Providing a member.
  • the diffusion film preferably has a haze value of 85% or more.
  • the second form of the first aspect of the present invention is a transmittance adjusting member formed by arranging a plurality of transmittance adjusting bodies for adjusting the light transmittance on the surface of the optical member, and diffusing and uniformizing the light.
  • a transmittance adjusting member formed by arranging a plurality of transmittance adjusting bodies for adjusting the light transmittance on the surface of the optical member, and diffusing and uniformizing the light.
  • an optical member obtained by laminating a diffusion film to be laminated, wherein a maximum dimension of the transmittance adjusting body is 500 ⁇ m or less and a haze value of the diffusion film is 85% or more.
  • a transmittance adjusting member in which a plurality of transmittance adjusting bodies that adjust light transmittance are arranged on the surface of an optical member, and light is diffused and uniformized
  • an optical member having a ratio DZS of 3.0 or more with the maximum dimension S of the rate adjuster is provided.
  • the optical member of the first aspect a light source, and the light source force radiate the emitted light toward the rectangular planar force toward the optical member.
  • a planar lighting device including a light guide plate.
  • the second form of the second aspect of the present invention is the optical member of the first aspect, a light source, and a light guide plate that emits light emitted from the light source force toward the optical member in a rectangular plane force.
  • the third aspect of the second aspect of the present invention provides the optical member of the first aspect and a light source.
  • the optical member is a light guide plate light guide plate that emits light emitted from the light source from a rectangular plane toward the optical member, and the transmittance adjusting body is disposed on a light exit surface of the light guide plate Provided is a planar lighting device.
  • the light guide plate is formed to have a rectangular light exit surface, a thick portion that is substantially parallel to one side of the light guide plate and located at a substantially central portion of the rectangular light exit surface, and substantially parallel to the thick portion.
  • the thickness decreases from the thick portion toward each of the pair of thin end portions on both sides in a direction substantially perpendicular to the one side, and a pair of inclined back surfaces are formed on both sides of the parallel groove.
  • a pair of inclined back surface portions, and the parallel grooves are formed by a pair of contour lines intersecting at the apexes with a narrower interval toward the rectangular light exit surface in the cross-sectional shape in the orthogonal direction.
  • each contour line of the parallel groove in the cross-sectional shape in the orthogonal direction is inclined with respect to a line perpendicular to the rectangular light exit surface.
  • Has a portion angle is changed, from the front end side closer to the apex, towards the base end side of the distant prior Symbol parallel grooves from the apex preferred that an acute angle.
  • the light guide plate includes a rectangular light emission surface and an inclined back surface that is inclined with respect to the light emission surface so that the plate thickness decreases from one side of the light emission surface toward the opposite side;
  • a light incident surface formed on a surface perpendicular to the light emission surface, and an end surface formed on a surface perpendicular to the light emission surface and perpendicular to the light emission surface. Is preferred.
  • a third aspect of the present invention is a backlight unit that also has the surface illumination device power of the second aspect;
  • a liquid crystal display device having a liquid crystal display panel disposed on the light emission surface side of the knock light unit, and the backlight unit and a drive unit for driving the liquid crystal display panel.
  • the transmittance adjusting body by defining the maximum dimension of the transmittance adjusting body and the optical characteristics of the diffusion film, the transmittance adjusting body can be prevented from being visually recognized, and the brightness can be reduced without reducing the brightness.
  • An optical member capable of improving unevenness of distribution, a planar illumination device using the same, and a liquid crystal display device can be provided.
  • the transmittance adjusting body is visually recognized by defining the maximum dimension S of the transmittance adjusting body and the distance D between the transmittance adjusting body and the diffusion film.
  • FIG. 1 is a configuration diagram showing an outline of a liquid crystal display device having a planar illumination device using the optical member of the present invention.
  • FIG. 2 is a cross-sectional view showing an outline of the backlight unit used for determining the visual recognition limit value.
  • FIG. 3 is a diagram showing lightness B and the rate of change dB / dx when the transmittance adjusting body is visually recognized.
  • FIG. 4 is a diagram showing brightness B and its change rate dB / dx when the transmittance adjusting body is not visually recognized.
  • FIG. 5A is a schematic cross-sectional view showing a state in which a prism sheet is disposed between the reflective sheet and the inclined surface of the light guide plate
  • FIG. 5B is a schematic view of the reflective sheet and the inclined surface of the light guide plate
  • FIG. 5C is a schematic plan view of the prism sheet disposed therebetween as seen from the light guide plate side
  • FIG. 5C is a schematic cross-sectional view of the prism sheet.
  • FIG. 6A is a schematic cross-sectional view around the parallel groove of the light guide plate having a hyperbolic cross-sectional shape perpendicular to the length direction of the pair of front end surfaces of the parallel groove
  • FIG. 6B is a pair of parallel grooves.
  • Length of tip 6C is a schematic cross-sectional view of the periphery of the parallel groove of the light guide plate having an elliptical cross-sectional shape
  • FIG. Fig. 6D is a schematic cross-sectional view around the parallel groove of the light guide plate formed by partial force of two circular arc curves symmetrical to the center line perpendicular to the light exit surface of the light guide plate.
  • the cross-sectional shape perpendicular to the longitudinal direction of the pair of tip surfaces of the pair is formed by partial forces of two parabolas symmetrical to the center line passing through the center of the parallel groove and perpendicular to the light exit surface of the light guide plate. It is a schematic sectional drawing of the parallel groove periphery of a light-guide plate.
  • FIG. 7A shows a parallel shape of a light guide plate in which a cross-sectional shape perpendicular to the length direction of a pair of front end surfaces of parallel grooves forms two curved forces that are convex toward the center of the parallel grooves.
  • Fig. 7B is a schematic cross-sectional view of the periphery of the groove.
  • Fig. 7B shows a combination of a convex curve and a concave curve with a cross-sectional shape perpendicular to the length direction of the pair of tip surfaces of the parallel groove.
  • FIG. 6 is a schematic cross-sectional view around a parallel groove of a light guide plate in which a curved force is also formed.
  • FIG. 8A is a cross-sectional view perpendicular to the length direction of a pair of base end faces of parallel grooves formed around a line segment having a sharper angle than the pair of front end faces.
  • FIG. 8B is a schematic cross-sectional view, and FIG. 8B is a cross-sectional view perpendicular to the length direction of a pair of base end surfaces of the parallel grooves formed around the parallel grooves of the light guide plate formed by a concave curve toward the center of the parallel grooves. It is a schematic sectional drawing.
  • FIG. 9 is a schematic cross-sectional view showing another example of a light guide plate that can be suitably used in the present invention.
  • FIG. 10 is an example of a halftone dot pattern formed on the light exit surface side of the light guide plate.
  • FIG. 11A is a schematic cross-sectional view showing a state in which a prism is formed on an inclined surface of a light guide plate
  • FIG. 11B shows a light exit surface of the inclined surface of the light guide plate on which the prism is formed. It is a schematic plan view seen from the side.
  • FIG. 12 is a schematic cross-sectional view showing a state in which prisms are formed on the inclined surface and the light exit surface of the light guide plate.
  • FIG. 13 is a diagram showing an outline of a tandem type planar illumination device using the optical member of the present invention.
  • FIG. 14 is a schematic perspective view of a surface light source device having a conventional light guide plate.
  • FIG. 15 is a graph of luminance on the exit surface of the light guide plate of the surface light source device shown in FIG. is there.
  • FIG. 1 is a diagram showing an outline of a liquid crystal display device having a planar illumination device using the optical member of the present invention.
  • 1A is a perspective view of the liquid crystal display device
  • FIG. 1B is a cross-sectional view of the liquid crystal display device shown in FIG. 1A.
  • the liquid crystal display device 10 basically includes a planar illumination device (hereinafter also referred to as a backlight unit) 2, a liquid crystal display panel 4 disposed on the light emission surface side of the backlight unit 2, and a drive for driving them. With unit 6.
  • the liquid crystal display panel 4 applies a partial electric field to liquid crystal molecules arranged in a specific direction in advance to change the arrangement of the molecules, and utilizes the change in the refractive index generated in the liquid crystal cell. Characters, figures, images, etc. are displayed on the surface of the display panel 4.
  • the drive unit 6 applies a voltage to the transparent electrode in the liquid crystal display panel 4 to change the direction of the liquid crystal molecules to control the transmittance of light transmitted through the liquid crystal display panel 4.
  • the backlight unit 2 is a device that irradiates light from the back of the liquid crystal display panel 4 to the entire surface of the liquid crystal display panel 4.
  • the backlight unit 2 is substantially the same light emission surface (light emitting surface) as the image display surface of the liquid crystal display panel 4. Surface).
  • the knock light unit 2 basically includes a light source 12, a light guide plate 18, a reflector 20, a reflection sheet 22, a transmittance adjusting member 28, a diffusion film 14, Prism sheets 16 and 17.
  • a light source 12 a light guide plate 18, a reflector 20, a reflection sheet 22, a transmittance adjusting member 28, a diffusion film 14, Prism sheets 16 and 17.
  • the transmittance adjusting body 26 arranged on the transparent film 29, the diffusion film 14, and the prism sheets 16, 17 are laminated.
  • the transmittance adjusting body 26 and the diffusion film 14 are collectively referred to as an optical member.
  • the light source 12 is a rod-like (linear) light source and is used to illuminate the liquid crystal display panel 4.
  • the light source 12 is disposed in a parallel groove 18 f formed in the light guide plate 18.
  • the rod-shaped light source 12 for example, a cold cathode tube, a fluorescent tube, an LED (light emitting diode) or the like can be used.
  • a cylindrical or prismatic transparent light guide having a length equivalent to the parallel groove 18f of the light guide plate 18 is used, and the LED is disposed on the side of the light guide.
  • Such an LED light source is capable of emitting light from the side force LED of the light guide used and emitting light from the top and bottom surfaces of the light guide.
  • the light guide plate 18 includes a rectangular light exit surface 18a, a thick portion 18b parallel to one side thereof, and a pair of thin end portions 18c formed on both sides of the thick portion 18b in parallel to the one side. Then, the thickness is reduced by directing the thin end portions 18c on both sides in the direction perpendicular to the one side from the thick portion 18b, A pair of inclined back surface portions 18e forming the inclined surface 18d, and a parallel groove 18f for accommodating the light source 12 formed in parallel with the one side in the thick portion 18b.
  • the light guide plate 18 has a flat surface on one side to form a light emission surface 18a, and the other surface has a plate thickness according to the direction of force on one side from the thick wall portion 18b.
  • a pair of inclined surfaces 18d are formed so as to be thinner with respect to one surface.
  • it is good also as a force curved surface which forms the inclined surface 18d as a plane.
  • the light guide plate 18 has a parallel surface 18g parallel to the light exit surface 18a between the inclined surface 18d and the base end surface 18i on the other surface. That is, in the thick portion 18b of the light guide plate 18, a parallel surface 18g extending from the inclined surface 18d is provided. Such a parallel surface 18g is not necessarily provided, but is preferably provided because it can improve the light use efficiency.
  • the light guide plate 18 is manufactured using, for example, a method in which heated raw material resin is molded by extrusion molding or injection molding, a casting polymerization method in which monomers, oligomers, and the like are molded in a mold. Can do.
  • Examples of the material of the light guide plate 18 include PET (polyethylene terephthalate), PP (polypropylene), PC (polycarbonate), PMMA (polymethylol methacrylate), benzyl methacrylate and MS resin, and other acrylic resins.
  • Transparent resin such as C OP (cycloolefin polymer) can be used.
  • the transparent resin may be mixed with fine particles for scattering light, whereby the light emission efficiency from the light emission surface 18a can be further increased.
  • a parallel groove 18f for accommodating the light source 12 is formed extending in the longitudinal direction.
  • the depth of the parallel groove 18f is determined so that a part of the light source 12 does not protrude from the lower surface of the light guide plate 18. Is preferably determined.
  • the thickness of the thick portion 18b and the thin end portion 18c of the light guide plate 18 can be arbitrarily changed according to the dimensions of the light source 12.
  • the parallel groove 18f of the light guide plate 18 may be formed in a direction perpendicular to the longitudinal direction of the light guide plate 18, but in order to increase the light use efficiency from the light source 12 accommodated in the parallel groove 18f. Is preferably formed in the longitudinal direction.
  • the parallel groove 18f constitutes a pair of distal end surfaces 18h and a proximal end portion constituting the distal end portion thereof.
  • the base end surface 18i is steeper than the front end surface 18h relative to the light exit surface 18a. That is, the maximum angle formed by the tangent plane of the tip end surface 18h and the light exit surface 18a, that is, the angle (inclination angle) ⁇ formed by the tangential plane of the base end surface 18i and the light exit surface 18a is greater than the maximum tilt angle ⁇ . large.
  • the side force that forms the parallel groove 18f also enters the light guide plate 18 and is reflected by the inclined surface 18d of the light guide plate 18. After that, the light exits from the light exit surface 18a. At this time, a part of light on the lower surface of the light guide plate 18 leaks, but the leaked light is reflected by the reflection sheet 22 formed on the inclined surface 18d side of the light guide plate 18 and again of the light guide plate 18. It enters the interior and exits from the light exit surface 18a. Thus, uniform light is emitted from the light exit surface 18a of the light guide plate 18.
  • the angle (taper) of the inclined surface 18d is set so that the light beam effectively reaches the light exit surface 18a at a right angle and in a parallel direction (depth direction). It is preferable to limit. In other words, it is preferable that the angle (taper) of the inclined surface 18d is such that a part of the light beam emitted from the light source 12 and incident on the light guide plate 18 is totally reflected by the light emitting surface 18a (back surface).
  • the parallel groove 18f of the light guide plate 18 has a cross-sectional shape perpendicular to the length direction of the parallel groove 18f, the tip portion of which forms a triangle, and the base end portion of which forms a rectangle. It is formed to have a convex home base shape on the 18a side. Therefore, the pair of leading end surfaces 18h of the parallel grooves 18f are inclined at a predetermined angle with respect to the vertical plane passing through the center of the light source perpendicular to the light emitting surface 18a, with one end of each of them intersecting each other.
  • the cross-sectional shape is formed by two line segments (slopes) having a predetermined angle of inclination forming one vertex of the triangle.
  • a pair of base end surfaces 18i of the parallel grooves 18f of the light guide plate 18 are connected to the other ends of the pair of front end surfaces 18h, and are parallel and symmetrical with respect to the vertical surface.
  • the cross-sectional shape is formed by line segments that are in contact with the remaining two vertices of the triangle and are perpendicular to the light exit surface 18a connected to the parallel surface 18g of the light guide plate 18, respectively.
  • the reflection sheet 22 reflects the light leaking from the inclined surface 18d of the light guide plate 18 and makes it incident on the light guide plate 18 again, thereby improving the light use efficiency.
  • Reflective sheet 22 Is formed so as to cover the inclined surface 18d of the light guide plate 18.
  • the reflection sheet 22 may be formed of any material as long as it can reflect light leaking from the inclined surface 18d of the light guide plate 18.
  • a filler is applied to PET, PP (polypropylene), or the like.
  • a resin sheet with increased reflectivity by forming voids by stretching after kneading, a sheet with a mirror surface formed by aluminum deposition or the like on the surface of a transparent or white resin sheet as described above, or a metal foil such as aluminum or the like It can be formed of a resin sheet carrying a metal foil, or a thin metal plate having sufficient reflectivity on the surface.
  • the reflector 20 is provided on the lower surface of the light source 12 so as to close the parallel grooves 18f of the light guide plate 18.
  • the reflector 20 reflects the light on the lower surface of the light source 12 to allow the side wall force light that forms the parallel grooves 18 f of the light guide plate 18 to enter the light guide plate 18.
  • the reflector 20 can be formed of, for example, the same material as that of the reflection sheet, that is, a resin material, a metal foil, or a metal plate that gives the surface sufficient reflectivity.
  • the transmittance adjusting member 28 reduces unevenness in luminance of light emitted from the light guide plate 18, and is a transparent film 29 that is an optical member having light transmittance, and the surface of the transparent film 29.
  • a plurality of transmittance adjusting bodies 26 are disposed on the surface facing the light guide plate 18 with a predetermined density distribution.
  • the transparent film 29 has a film-like shape and is light transmissive, and is disposed between the light guide plate 18 and the diffusion film 14.
  • Transparent film 29 is made of PET (polyethylene terephthalate), PP (polypropylene), PC (polycarbonate), PMMA (polymethylol methacrylate), benzyl methacrylate, MS resin, other acrylic resins, or COP. It is formed of an optically transparent member such as (cycloolefin polymer).
  • the transmittance adjusting body 26 has a predetermined transmittance, and the plurality of transmittance adjusting bodies 26 have a predetermined density distribution / 0 (X, y) represented by the following formula (1) on the surface of the transparent film. It is preferable to be arranged in
  • This density distribution is a preferred example of the arrangement pattern of the transmittance adjusting body 26 arranged to suppress luminance unevenness, and is an example of an arrangement pattern, and was found by the present inventor.
  • the light guide plate 1 By arranging a plurality of transmittance adjusting bodies 26 with a predetermined density distribution, the light guide plate 1
  • the brightness unevenness of the light emitted from the eight light exit surfaces 18a can be reduced.
  • the transmittance adjusting body 26 can be formed on the surface of the transparent film 29 on the light guide plate 18 side by offset printing, Darvia intaglio printing, screen printing, ink jet printing, or the like.
  • Offset printing is excellent in productivity, and gravure intaglio printing is excellent in productivity, and the thickness of ink can be changed, so that high-quality printing with rich density gradation is possible.
  • screen printing can increase the thickness of ink applied as a transmittance adjusting body, and can reduce the transmittance of the transmittance adjusting body without increasing the ink concentration.
  • inkjet printing can print directly on a three-dimensional object, it is preferable to use this method when printing directly on a light guide plate or the like. These methods for forming the transmittance adjusting body are preferably properly used depending on the purpose.
  • the plurality of transmittance adjusting bodies 26 have the largest dimension (hereinafter also referred to as “dot size”) (hereinafter “maximum dimension of transmittance adjusting body” t). It consists of the following small dots.
  • the shape of the dot is not particularly limited, and may be a rectangle, triangle, hexagon, circle, ellipse, or the like.
  • the transmittance adjustment body By setting the maximum size of the transmittance adjustment body to 500 m or less, when the backlight unit 2 is configured in combination with a light source, a light guide plate, etc., the transmittance adjustment body can be seen from the light exit surface of the knock light unit 2. It becomes difficult to see. When the transmittance adjusting body of the light emission surface force of the knock light unit 2 is visually observed, the transmittance adjusting body prevents the homogeneity of the light source. Therefore, a uniform light source can be obtained by making the transmittance adjusting body visible.
  • the minimum dimension of the transmittance adjuster (the smallest dimension) is 20 m in consideration of manufacturing technology and manufacturing cost.
  • the maximum dimension of the transmittance adjusting body is more preferably 200 m or less. Transmittance This is because if the maximum dimension of the adjusting body is designed with this size, the transmittance adjusting body will not be seen from the light exit surface of the backlight unit 2.
  • the diffuse reflector is a product obtained by coating pigments such as silica, titanium oxide, and zinc oxide that scatter light, or beads such as rosin, glass, and zirconium oxide together with a binder.
  • the diffusion film 14 is for diffusing and uniformizing light emitted from the light exit surface 18a of the light guide plate 18.
  • the diffusion film 14 can improve the unevenness of the luminance distribution by setting the optical characteristics in consideration of the relationship with the transmittance adjusting body, and can emit the light emitted from the light exit surface of the light guide plate. More uniform outgoing light can be obtained.
  • the optical characteristics set for the diffusion film 14 are haze value, viewing angle and total light transmittance, and the dot size of the transmittance adjusting body 26 is set to 500 m or less.
  • the optical properties of the diffusing film are set to 2.5 ° or more for the half angle of view, 90% or less for the total light transmittance, or 85% or more for the haze.
  • two or more of these optical characteristics may be combined.
  • the haze value may be set to 85% or more and the viewing half-value angle may be set to 2.5 ° or more.
  • the half-value angle of the field of view generally indicates an angle at which the intensity of the light that penetrates the normal line at the center of the light emission plane is defined as 0 ° light and the intensity becomes half value.
  • the diffusion film 14 is made of, for example, PET (polyethylene terephthalate), PP (polypropylene), PC (polycarbonate), PMMA (polymethyl methacrylate), benzyl methacrylate, MS resin, and other acrylic resins. Or COP (cycloolefin polymer) It is formed by imparting light diffusibility to a film-like member made of such an optically transparent resin.
  • the manufacturing method is not particularly limited.
  • the surface of the flat plate member is subjected to surface roughening by fine uneven processing or polishing (hereinafter, the surface on which these are applied is referred to as “sand-rubbed surface”) to improve the diffusibility.
  • a material having high reflectivity and low light absorption for example, a metal such as Ag or A1.
  • the diffusion film 14 may be a mat type or coating type diffusion film.
  • the diffusing film 14 it is preferable to use a film-like member having a thickness of 500 ⁇ m or less, using the above-mentioned material and imparting light diffusibility.
  • the diffusion film 14 may be arranged at a predetermined distance from the light exit surface 18a of the light guide plate 18. The distance may be appropriately changed according to the light amount distribution from the light exit surface 18a of the light guide plate 18. obtain.
  • the light emitted from the light exit surface 18a of the light guide plate 18 is transferred between the light exit surface 18a and the diffusion film 14. It is further mixed (mixed). As a result, the luminance of the light that passes through the diffusion film 14 and illuminates the liquid crystal display panel 4 can be made more uniform.
  • a method of separating the diffusion film 14 from the light exit surface 18a of the light guide plate 18 by a predetermined distance for example, a method of providing a spacer between the diffusion film 14 and the light guide plate 18 can be used.
  • the light emitting surface 18a of the light guide plate 18 corresponding to the parallel groove 18f is formed depending on the cross-sectional shape of the parallel groove 18f of the light guide plate 18. It is necessary to reduce the peak value of the brightness sufficiently, and a gap is provided between the diffusion film 14 and the light exit surface 18a of the light guide plate 18 to illuminate the diffusion film 14 force. The luminance distribution of light may be made uniform.
  • the prism sheets 16 and 17 are transparent sheets formed by arranging a plurality of prisms in parallel. The prism sheets 16 and 17 increase the light collecting property of the light emitted from the light exit surface 18a of the light guide plate 18 to increase the luminance. Can be improved.
  • One of the prism sheets 16 and 17 is disposed so that the extending direction of the prism row is parallel to the parallel groove 18f of the light guide plate 18, and the other is disposed vertically. That is, the prism sheets 16 and 17 are arranged so that the extending directions of the prism rows are perpendicular to each other.
  • the prism sheets 16 and 17 are arranged so that the apex angle of the prism faces the light exit surface 18 a of the light guide plate 18.
  • the prism sheets 16 and 17 are arranged in the order in which the prism sheet 16 having a prism extending in a direction parallel to the parallel groove of the light guide plate is disposed immediately above the light guide plate.
  • a prism sheet 17 having prisms extending in a direction perpendicular to the parallel grooves 18f of the light guide plate 18 may be disposed on the 16 or vice versa. Further, it is not always necessary to use two prism sheets.
  • a sheet in which optical members similar to prisms are regularly arranged may be used instead of the force prism sheet using the prism sheets 16 and 17.
  • an element having a lens effect for example, a sheet regularly provided with optical members such as a lenticular lens, a concave lens, a convex lens, and a pyramid type can be used instead of the prism sheet.
  • the optical member of the present invention comprising the transmittance adjusting member and the diffusion film and the backlight unit (planar illumination device) of the present invention
  • the maximum size of the transmittance adjusting body and the diffusion film By defining the optical characteristics and considering the relationship between the diffusion film and the transmittance adjusting body, the unevenness of the luminance distribution can be improved, and a homogeneous light source can be obtained. That is, it is possible to prevent the transmittance adjusting body from being visually recognized and to reduce luminance unevenness. That is, the transmittance adjusting body can be prevented from being visually recognized, and the unevenness of the luminance distribution can be further reduced. Furthermore, it is possible to prevent the luminance from being reduced.
  • Example 1 when a liquid crystal display device is manufactured by combining the planar lighting device of the present invention and a liquid crystal display panel, a liquid crystal display device with good image quality can be provided.
  • FIG. 2 is a cross-sectional view showing a schematic configuration of the backlight unit used in this example.
  • the knock light unit 30 includes a light source 12, a light guide plate 38, a diffusion film 14, a prism sheet 16, a reflector 20, a reflection sheet 22, and a transmittance adjusting body unit 28. .
  • a cold cathode tube having a diameter R of 2 mm was used as the light source 12.
  • a light guide plate 38 having the shape shown in FIG. 2 and having the following dimensions was used.
  • the distance L from the center of the light guide plate 38 (the center of the parallel groove 38f) to one end face of the light guide plate 38 is 15 mm, and the thick part 38b near the center of the light guide plate 38 has the thickest part dO 4
  • the distance between the tip of the parallel groove 38f (the center of the parallel groove 38f) and the light exit surface is dl, and the thickness d2 of the end face of the light guide plate 38 is 1.5mm.
  • the light guide plate 38 which has the widest V ⁇ part G1 and a width of 4 mm, was used.
  • the visibility limit value is the change in brightness that makes it impossible to visually see the transmittance adjustment body by sensory evaluation when the transmittance adjustment body is observed from a position 30 cm away from the light exit surface of the knocklight unit.
  • the rate means dB / dx.
  • a backlight unit 30 using an optical member formed by laminating the transmittance adjusting member 28 and the diffusion film 14 under various conditions was manufactured, and the following method was performed for each of the manufactured backlight units 30. The sensory evaluation was performed.
  • the sensory evaluation was performed by observing the transmittance adjusting body at a position 30 cm away from the light emitting surface of the knocklight unit 30 by 20 subjects. As a result of the observation by the test subjects, when all 20 people could not see the transmittance adjustment body! / ⁇ , the transmittance adjustment body was not visible, and even one of the 20 people had the transmittance adjustment body. The case where the transmittance adjusting body was visually recognized was evaluated as the case where it was evaluated that
  • the brightness B and the rate of change dBZdx were measured for each of the cases where the transmittance adjusting body was visually recognized and when the transmittance adjusting body was not visually recognized! Specifically, an 85mm lens (Nikon Corporation) was attached to a digital camera (Fuji Photo Film Fine Pix S2Pro), and the exit surface of the backlight unit was photographed from a distance of 70 cm to obtain 8-bit image data.
  • an 85mm lens Nakon Corporation
  • a digital camera Fluji Photo Film Fine Pix S2Pro
  • the lightness change rate dB / dx is the absolute value of the change in lightness ⁇ ⁇ ⁇ per 1 ⁇ (40 ⁇ ⁇ ).
  • Fig. 3B shows an example of the measurement result of the brightness ⁇ of the RGB component measured based on the image data obtained by photographing the light exit surface of the backlight unit when the transmittance adjusting body is visually recognized.
  • the brightness change rate dB / dx calculated based on the brightness B of each component shown in FIG. 3A is shown.
  • Fig. 4A shows an example of the measurement result of brightness B of the RGB component measured based on the image data obtained by photographing the light exit surface of the backlight unit when the transmittance adjusting body is not visually recognized, and Fig. 4B.
  • the brightness change rate dB / dx calculated based on the brightness B of each component shown in FIG. 4A is shown.
  • the horizontal axis position X [pixel] in FIGS. 3 and 4 is the origin in the axial direction of the light source from the center of the backlight unit (position on the light exit surface corresponding to the tip of the parallel groove of the light guide plate).
  • the position was 271 pixels (10840 m) away in the vertical direction. In other words, on the horizontal axis, the position of 271 pixels is the center of the backlight unit.
  • the visibility limit value of the brightness change rate that is, When the transmittance adjusting body is also observed at a position force 30 cm away from the light exit surface of the knocklight unit, the lightness change rate dBZdx is 3.0, which is substantially invisible by sensory evaluation. It became a force.
  • a backlight unit using an optical member in which a transmittance adjusting member having a different dimension (dot size) of the transmittance adjusting body and a diffusion film having different optical characteristics are laminated by being separated by 200 ⁇ m is provided. A plurality of them were produced, and whether or not the transmittance adjusting body was visually recognized (visibility) was evaluated for each backlight unit.
  • the optical characteristics of the diffusion film are the half-value angle of view, the total light transmittance, and the haze.
  • the density, particle diameter, type, amount of coating on the front and back of the diffusion film, etc. applied to the transparent film.
  • Various diffusion films having different optical properties were prepared.
  • Table 1 shows the brightness change rate and the visibility determination results obtained by measuring and calculating a plurality of knock light units in which the half-value angle of view of the diffusion film and the dot size of the transmittance adjusting body were changed. Is shown together with the half-value angle of view of the diffusion film of each backlight unit and the dot size of the transmittance adjuster.
  • the half-value angle of view was measured using a go-off otometer (Murakami Color Research Laboratory), the three-dimensional variable-angle luminous intensity, BP-200, ND10, S-polarized light on both the light source side and the light-receiving side, High Volt This is the value measured with 600 and aperture 6.8 mm ⁇ .
  • Table 2 shows the results of the brightness change rate and the visibility determination results measured and calculated for each of the plurality of knock light units in which the total light transmittance of the diffusion film and the dot size of the transmittance adjuster were changed. Is shown together with the total light transmittance of each backlight unit and the dot size of the transmittance adjuster.
  • the total light transmittance [%] is a value measured using a single beam type haze meter (HZ-1 type manufactured by Suga Test Instruments Co., Ltd.). In this example, the measurement light is 7 using C light.
  • Table 3 shows the brightness change rate and the visibility judgment for each of the backlight units in which the haze of the diffusion film and the dot size of the transmittance adjuster were changed. The results are shown together with the haze of each backlight unit and the dot size of the transmittance adjuster.
  • the haze [%] is a value measured using a single beam type haze meter (HZ-1 type, manufactured by Suga Test Instruments Co., Ltd.). Also in this example, measurement was performed using C light as measurement light. Visibility was determined by the same method as in Table 1.
  • Table 4 shows the brightness change rate, brightness [cdZcm 2 ], and visibility determination for each of a plurality of backlight units in which the haze and viewing half-value angle of the diffusion film were changed. The results are shown together with the haze and viewing half-value angle of the diffusion film of each backlight unit.
  • the dot sizes of the transmittance adjusting bodies of the examples shown in Table 4 were all 450 ⁇ m.
  • the haze and viewing half-value angle of the diffusion film are values measured by the same method as described above, and the luminance is a value measured using a luminance meter (BM-7 manufactured by Topcon Corporation).
  • the brightness change rate is small enough that the transmittance adjuster is not visible.
  • the brightness change rate can be set to 3 or less, and it is considered that the transmittance adjusting body can be prevented from being visually recognized from the light exit surface. That is, the transmittance adjusting body can be prevented from being visually recognized, and the unevenness of the luminance distribution can be further reduced.
  • the brightness change rate increases as the dot size of the transmittance adjusting body increases.
  • the dot size of the transmittance adjuster is 500 ⁇ m or less and the total light transmittance is 90% or less, the lightness change rate is small enough that the transmittance adjuster is not visible.
  • the brightness change rate can be set to 3 or less, and it is considered that the transmittance adjusting body can be prevented from being visually recognized from the light exit surface. That is, the transmittance adjusting body can be prevented from being visually recognized, and the unevenness of the luminance distribution can be further reduced.
  • the dot size of the transmittance adjuster is 500 ⁇ m or less and the haze is 85%. If it is more than the above, the lightness change rate takes a small value such that the transmittance adjusting body is not visually observed. In other words, the brightness change rate can be set to 3 or less, and it is considered that the transmittance adjusting body can be prevented from being visually recognized from the light exit surface. That is, the transmittance adjusting body can be prevented from being visually recognized, and the unevenness of the luminance distribution can be further reduced.
  • the rate of change in brightness will be Take a small value that is not visible.
  • the brightness change rate can be set to 3 or less, and the light exit surface force can be prevented from being visually recognized by the transmittance adjusting body.
  • the transmittance adjusting body can be prevented from being visually recognized, and the unevenness of the luminance distribution can be further reduced.
  • the transmittance adjusting body is recognized without reducing the average luminance of the light emitted from the planar illumination device.
  • the present invention is not limited to this.
  • the unevenness of the luminance distribution can also be improved by considering the arrangement interval between the diffusion film 14 and the transmittance adjusting body 26 in accordance with the maximum dimension of the transmittance adjusting body 26.
  • the maximum dimension of the transmittance adjusting body 26 is set to 500 m or less, and the ratio between the distance D between the transmittance adjusting body 26 and the diffusion film 14 and the maximum dimension S of the transmittance adjusting body 26 D ZS Is 3.0 or more.
  • the ratio DZS depends on the maximum size of the transmittance adjusting body 26 and the transmittance adjusting body 26. It can be set by adjusting the distance D to the diffusion film 14.
  • an acrylic plate or the like is provided between the transmittance adjusting member 28 on which the transmittance adjusting body 26 is disposed and the diffusion film 14.
  • a spacer is arranged at the end (edge) of the optical member composed of the transmittance adjusting member 28 and the diffusion film 14 that can be performed, and a support body that supports the diffusion film that can be performed by air is provided. You may carry out by adjusting the thickness of the support body.
  • the brightness change rate of the backlight unit in which the transmittance adjustment body is visually recognized is greater than 3.0, and the transmittance adjustment body is not visible.
  • the brightness change rate of the light unit was 3.0 or less.
  • the lightness change rate of the visual recognition limit value is 3.0.
  • a backlight unit using an optical member formed by laminating a transmittance adjusting member having different dimensions (dot size) of the transmittance adjusting body and a diffusion film having different optical characteristics at different intervals is manufactured.
  • the visibility of the transmittance adjusting body on the light exit surface was evaluated.
  • the dot size S of the transmittance adjusting body is in the range of 60 ⁇ m ⁇ S ⁇ 450 ⁇ m
  • the distance D between the transmittance adjusting member and the diffusion film is 200 ⁇ m ⁇ D ⁇ 5000 ⁇ m. Adjusted (set) the range.
  • the distance D between the transmittance adjusting member and the diffusion film was adjusted by holding the diffusion film with a spacer and a diffusion film support (not shown).
  • Table 5 shows the measured brightness change rate and visibility judgment for the backlight unit in which the dot size S of the transmittance adjusting body and the distance D between the transmittance adjusting member and the diffusion film were changed. The results are shown together with the dot size S and distance D of each backlight unit.
  • the transmittance adjustment body is easily visible.
  • the dot size of the transmittance adjusting body is 450 ⁇ m, the transmittance adjusting body is visually observed when the ratio DZS is 2.2 or less.
  • the dot size of the transmittance adjusting body is 130 m, the transmittance adjusting body is visually observed when the ratio DZS is 1.5 or less.
  • the dot size of the transmittance adjusting member is 500 ⁇ m or less and the ratio DZS between the distance D between the transmittance adjusting body and the diffusion film and the dot size S is 3.0 or more,
  • the lightness change rate is 3.0 or less, and it is considered that the transmittance adjustment body is not visually recognized as uneven brightness.In other words, it is possible to prevent the transmittance adjustment body from being visually recognized and to further reduce uneven brightness distribution. be able to.
  • the prism sheet 19 may also be provided between the reflection sheet 22 and the light guide plate 18.
  • 5A is a schematic cross-sectional view showing a state in which the prism sheet 19 is disposed between the reflective sheet 22 and the inclined surface 18d of the light guide plate 18.
  • FIG. 5B is an inclined surface 1 of the reflective sheet 22 and the light guide plate 18.
  • FIG. 5 is a schematic plan view of the prism sheet 19 disposed between the light guide plate side and the light guide plate side.
  • c is a schematic cross-sectional view of a prism sheet.
  • the prism sheet 19 provided between the reflection sheet 22 and the inclined surface 18d of the light guide plate 18 is arranged so that the direction in which the prism 23a extends is perpendicular to the parallel groove 18f of the light guide plate 18, You may arrange
  • an optical member having a lens effect that may be an optical member having the same effect as the prism sheet, such as a lenticular lens, a concave lens, a convex lens, a pyramid type, etc.
  • a sheet in which optical members are regularly arranged may be provided.
  • the prism sheet 19 is of course unnecessary, and the prism sheet One or both of 16 and 17 need not be used.
  • a transparent film 9 is selected as an optical member having light transmittance, and a transmittance adjusting member 26 is arranged thereon to form a transmittance adjusting member 28.
  • a diffusing film, a prism sheet, or a light guide plate may be selected as the optical member. That is, the transmittance adjusting body can be arranged directly on the surface of the diffusion film, the prism sheet, or the light guide plate. In this case, it is preferable to arrange the transmittance adjusting body by ink jet printing that can directly print on a three-dimensional object.
  • the transmittance adjusting body on the surface of the diffusion film, the prism sheet or the light guide plate, it is not necessary to configure the transmittance adjusting member by arranging the transmittance adjusting body on the transparent film. Therefore, the transparent film can be omitted, the structure of the layers constituting the knock light unit can be simplified, and the manufacturing cost can be reduced.
  • the transmittance adjusting member 28 when the transmittance adjusting member 28 is disposed between the light guide plate and the diffusion film or between the diffusion film and the prism sheet, the position of the transmittance adjusting member 28 is shifted in the manufacturing process after the transmittance adjusting member is disposed. there is a possibility. Since the transmittance adjusting member reduces unevenness of the luminance distribution such as bright lines and dark lines, it is important to prevent displacement of the arrangement position. When the transmittance adjusting body is arranged directly on the light exit surface of the light guide plate, it is possible to prevent a shift in the arrangement position of the transmittance adjusting member. Furthermore, it is not necessary to align the transmittance adjusting body in the assembly process of the knocklight unit.
  • the alignment makeup may be applied to a region other than the region where the transmittance adjusting body is disposed. This facilitates alignment in the assembly process of the knocklight unit.
  • the cross-sectional shape of the parallel groove 18f is a home base shape in which the tip end portion is a triangle and the base end portion is a rectangle. Any shape may be used as long as the portions intersect with each other and the inclination of the proximal end portion connected to the distal end portion is steeper than the inclination of the distal end portion. That is, the cross-sectional shape of the parallel groove 18f is directed to the light exit surface 18a at the tip portion, and the distance between the parallel grooves 18f is narrowed to form a pair of contour lines that intersect at the apex.
  • the shape has a part where the angle of inclination with respect to a line perpendicular to the vertical axis changes, and is farther from the apex (front end face 18h) near the apex, and the base end side (base end face 18i) of the parallel groove has an acute angle. If so!
  • the base of the parallel groove farther from the vertex than the inclination angle (maximum inclination angle ⁇ ) formed by the contour line on the tip side (tip surface 18h) close to the vertex is the light exit surface 18a.
  • Any shape may be used as long as the inclination angle (inclination angle ⁇ ) formed by the contour line on the end side (base end face 18i) and the light exit surface 18a is larger.
  • the pair of front end faces 40 of the parallel grooves 18f can be formed into a hyperbola shape, and as shown in FIG. 6B, the pair of front end faces 42 of the parallel grooves 18f can be formed into an oval shape.
  • the cross-sectional shape of the pair of tip surfaces of the parallel grooves 18f of the light guide plate 18 may be a catenary line shape.
  • the cross-sectional shape of the parallel groove is such that the apex of the parallel groove, that is, the deepest part (the connection part of the side wall forming the parallel groove) is a cusp. It can also be shaped. That is, two cross-sectional shapes of a pair of front end surfaces of the parallel grooves are symmetrical with respect to a center line perpendicular to the light exit surface of the light guide plate through the center of the parallel grooves having one sharp intersection that intersects each other. It can be formed from a part of a curve or straight line.
  • the light guide Even if the cross-sectional shape of the parallel groove of the plate is any of the above shapes, uniform light can be emitted from the light exit surface of the light guide plate.
  • the cross-sectional shape force of the pair of front end surfaces 50 of the parallel groove has a single intersection point that intersects each other, and passes through the center of the parallel groove 18f and is perpendicular to the light exit surface of the light guide plate
  • An example of the case where the partial force of two curves symmetric with respect to is also shown.
  • the light guide plate 18 shown in FIG. 6C has two symmetrical curves 51a and 51b that form a pair of front end surfaces 50 with respect to a center line X perpendicular to the light exit surface 18a of the light guide plate 18 through the center of the parallel groove 18f. Is an arc. In this case, as shown in FIG.
  • the center position of the arc 51a corresponding to one side wall forming the parallel groove 18f is different from the center position of the arc 5 lb corresponding to the other side wall.
  • the portion 52 where the arc-shaped side walls meet each other has a sharp shape as shown in FIG. 6C.
  • the cross-sectional shape of the pair of front end faces 53 of the parallel grooves is perpendicular to the light exit surface of the light guide plate through the center of the parallel grooves having one sharp intersection that intersects each other.
  • the partial force of two curves that are symmetrical about the center line is also present.
  • the light guide plate 18 shown in FIG. 6D has two symmetrical curves 54a and a pair of front end faces 53 with respect to a center line X passing through the center of the parallel groove 18f and perpendicular to the light exit surface 18a of the light guide plate 18.
  • 54b is a parabola.
  • the pair of front end surfaces 53 of the parallel groove 18f are arranged so that the focal point of the parabola 54a corresponding to one side wall of the parallel groove 18f and the focal point of the parabola 54b corresponding to the other side wall are different from each other. It is formed.
  • FIG. 6 shows an example of a light guide plate that is concave in the cross-sectional shape of the parallel grooves, in which the curves forming a pair of front end surfaces of the parallel grooves are directed toward the center of the parallel grooves.
  • FIG. 7A and FIG. 7B show another embodiment of the light guide plate that can be suitably used for different present inventions.
  • Figure 7A shows the cross-sectional shape force of a pair of tip surfaces 60 of the parallel groove 18f.
  • 7B is an example of a light guide plate formed from the curved lines 61a and 61b of FIG. 7.
  • FIGS. 7A and 7B shows a curved line 64a and 64b in which the cross-sectional shape of the pair of tip surfaces 63 of the parallel groove 18f is convex toward the center of the parallel groove 18f.
  • This is an example of a light guide plate formed by combining a curved force 66a and 66b and a curved force.
  • a light guide plate having parallel grooves having a cross-sectional shape as shown in FIGS. 7A and 7B can also emit light with sufficient light emission surface strength while suppressing generation of bright lines.
  • the pair of base end surfaces of the front end portion of the parallel groove are parallel to the light exit surface 18a in contact with the front end surface 18h and the parallel surface 18g.
  • Symmetrical vertical line segment The cross-sectional shape of the parallel groove 18f is directed to the light exit surface 18a, and the distance between the parallel grooves 18f is narrowed.It is composed of a pair of contour lines that intersect at the apex.
  • the inclination angle with respect to a line perpendicular to the exit surface changes, and it is farther from the apex than the tip side (tip surface) close to the apex, and the base end side (base end surface) of the parallel groove has an acute angle.
  • the cross-sectional shape of the pair of tip surfaces of the parallel grooves is a triangle
  • the cross-sectional shape of the pair of base end surfaces 70 of the parallel grooves is changed to the light exit surface 18a as shown in FIG. It is formed by a line segment (the hypotenuse) that has an inclination of a predetermined angle that is perpendicular to the line that passes through the center of the light source and is acute than the tip surface 18h. May be.
  • each base end face of the parallel groove is not limited to a straight line, and a curved line can also be used.
  • the cross-sectional shape of the pair of base end faces 72 of the parallel groove 18f is changed to the parallel groove 18f.
  • a concave curve may be formed by directing force toward the center.
  • various curves used for a pair of tip surfaces of parallel grooves such as a hyperbolic shape, an elliptical shape, and a parabolic shape, can be used.
  • the shape of the parallel grooves is not limited to this, and can be various shapes such as a combination of the shapes of the pair of distal end surfaces and the pair of proximal end surfaces described above.
  • the size of the pair of distal end surfaces and the pair of proximal end surfaces of the parallel grooves is sufficient if the light source can be arranged inside the parallel grooves, and the boundary position (contact position) between the pair of distal end surfaces and the pair of proximal end surfaces Is not particularly limited.
  • a joint (connection portion) between a pair of distal end surfaces and a pair of proximal end surfaces of a parallel groove, a joint between a pair of proximal end surfaces and a parallel surface of parallel grooves, and a parallel surface and an inclined surface
  • the seam should have a smooth shape with R> 0.01 [mm].
  • the surface of the light guide plate excluding the side surfaces of the parallel grooves (a pair of distal end surfaces and a pair of proximal end surfaces), for example
  • the prism sheet can be omitted, the light use efficiency as the planar illumination device can be improved, the device can be made compact, and the cost can be reduced. It is more preferable to form a large number of minute prisms having a predetermined shape on either the inclined surface or the exit surface, but it is more preferable to form such prisms on both the inclined surface and the light exit surface. preferable.
  • the apex angle 0 shall be 100 ° ⁇ ⁇ ⁇ 140 °
  • the prism formed on the light exit surface has apex angle 0 of 40 ° ⁇ ⁇ ⁇ 70 ° and p2 p2! /.
  • a pair of parallel surfaces is provided between the pair of inclined surfaces and the pair of base end surfaces of the parallel grooves.
  • the surface does not necessarily have to be provided, and a parallel surface may not be provided, and the inclined surface 80 and the base end surface 18i of the parallel groove 18f may be directly connected.
  • the density of halftone dots is high at a certain center line X, and both sides from the center line X (in the direction perpendicular to the center line). ) May be formed on the light exit surface 18a of the light guide plate 18 by, for example, printing.
  • Such a halftone dot pattern 92 is formed on the light exit surface 18a of the light guide plate 18 so that the center line X of the halftone dot pattern matches the position corresponding to the center line of the parallel groove of the light guide plate 18.
  • generation of bright lines and unevenness on the light exit surface 18a of the light guide plate 18 can be suppressed.
  • a thin sheet on which the halftone dot pattern is formed may be laminated on the light emitting surface.
  • the shape of the halftone dots can be any shape, such as a rectangle, a circle, or an ellipse, and the density of the halftone dots can be appropriately selected according to the intensity and spread of the bright line.
  • a portion corresponding to the halftone dot pattern may be roughened as a rubbing surface. Such a rubbing surface may be formed at the deepest part or the side wall of the parallel groove of the light guide plate.
  • the luminance distribution of the light emitted from the light exit surface largely depends on the shape of the tip portion of the parallel groove of the light guide plate
  • the shape of the parallel groove of the light guide plate is shown in the above-described present invention. By simply designing it so that it has a uniform shape, the brightness on the light exit surface of the light guide plate can be optimally adjusted and leveled.
  • the peak value of the relative luminance in the portion corresponding to the parallel groove is the average value of the relative luminance formed by the emitted light of the inclined back surface force.
  • the luminance is 10 times or less, and the luminance of the light exit surface force becomes substantially uniform.
  • the cross-sectional shape of the parallel grooves is semicircular or parabolic
  • the relative luminance increases at the central portion of the parallel grooves, that is, the position directly above the light source, and bright lines are generated. That is, in the conventional light guide plate having a semicircular or parabolic cross-sectional shape of the parallel grooves, the luminance on the light exit surface is not uniform.
  • the relative luminance of the central portion is low, so that the force for flattening the apex with a predetermined width is made a curved surface with a relatively small radius of curvature.
  • the luminance on the light exit surface can be made uniform.
  • the brightness in the portion corresponding to the parallel groove of the light guide plate changes according to the length of the flat portion.
  • the brightness can be increased by lengthening the flat end portion of the deepest portion of the parallel groove.
  • the length is too long, a bright line may be formed. It is preferably 20% or less of the diameter of the cathode tube, more preferably 10% or less.
  • luminance and illuminance can be handled in substantially the same manner.
  • the illuminance on the light exit surface of the light guide plate can be made uniform by designing the shape of the parallel grooves of the light guide plate to be the shape shown in the present invention.
  • the cross-sectional shape of the top (deepest part) of the tip of the parallel groove is chamfered flat or rounded at one sharp intersection so as to be symmetric with respect to the center line of the parallel groove.
  • the shape not only the shape but also an elliptical shape, a parabolic shape, or a hyperbolic shape may be acceptable.
  • the peak value of illuminance or luminance is reduced by making the top part (deepest part) of the tip part of the parallel groove a sand rubbing surface. Also good.
  • the light guide plate that can be suitably used in the present invention, it is formed on the light emission surface 18a of the light guide plate 18 other than the parallel grooves 18f, that is, on the portion corresponding to the inclined surface 18d (second portion).
  • the tip shape of the parallel groove 18f of the optical plate 18 is tapered, that is, the degree of tapering of the tip shape of the parallel groove 18f of the light guide plate 18 is controlled according to the value of this ratio.
  • the ratio is preferably 3 or less, more preferably 2 or less, as in the case of the second embodiment described later.
  • this ratio depends on the thickness of the knock light unit 2 (the distance between the light exit surface 18a of the light guide plate 18 and the diffusion sheet 14) and the diffusion sheet used in the knock light unit 2. It is preferable to set according to the diffusion efficiency and the number of sheets 14 and the diffusion efficiency and the number of sheets used of the prism sheets 16, 17 and 19.
  • the thickness of the knock light unit 2 (distance between the light emitting surface 18a of the light guide plate 18 and the diffusion sheet 14) can be increased to a certain extent (or larger), or the diffusion sheet used in the knock light unit 2
  • the number of used sheets with high diffusion efficiency of 14 can be increased, or when the number of sheets used with high diffusion efficiency of prism sheets 16, 17, and 19 can be increased, the light is emitted from the light exit surface 18a of the light guide plate 18.
  • light diffusion mixing, etc.
  • the ratio of the luminance peak values of the first portion of the exit surface 18a can be set to be large to some extent. However, if this is not the case, the cost can be reduced, but the value of this ratio needs to be set small.
  • the tip end portion where the parallel groove 18f is tapered has an angle with respect to the central force light exit surface 18a of the rod-shaped light source 12 and the perpendicular force (X). It is preferable that the portion is within 90 degrees on both sides, more preferably, the portion is within 60 degrees. That is, in order to reduce the luminance peak value of the first portion corresponding to the parallel grooves 18f of the light exit surface 18a of the light guide plate 18, the entire portion of the parallel grooves 18f may be tapered. However, if the peak value can be reduced, a predetermined tip portion may be used.
  • the shape of the parallel grooves of the light guide plate is directed toward the light exit surface, and the distance between the grooves is reduced. Consists of a pair of contour lines intersecting at a point, and each contour line has a portion whose inclination angle changes with respect to a line perpendicular to the light exit surface, and from the tip side (a pair of tip surfaces) near the apex By making the base end side (one pair of base end faces) of the distant parallel groove away from the apex a sharper angle, uneven brightness can be further reduced and the emission efficiency can be improved.
  • the cross-sectional shape of the parallel groove is a combination of a curve having another inclination angle ⁇ (> ⁇ ) with respect to the maximum inclination angle ⁇ of another hyperbola, parabola, or other curved line. Brightness unevenness can be reduced and the emission efficiency can be improved.
  • the surface of the light guide plate excluding the side surfaces of the parallel grooves (a pair of front end surfaces and a pair of base end surfaces), for example, a light emitting surface and a prism whose grooves are parallel to the axis of the rod-shaped light source directly on the flange or inclined surface. May be engraved.
  • the prism 25 may be formed directly on the inclined surface 18d of the light guide plate 18 as shown in FIG. 11A and ⁇ , and the prism 26 and the inclined surface 18d are formed on the light exit surface 18a of the light guide plate 18 as shown in FIG.
  • the prism 25 may be formed.
  • the prism by forming the prism on the surface of the light guide plate excluding the side surfaces of the parallel grooves (one pair of front end surfaces and one pair of base end surfaces), it is possible to obtain the same effect as when a prism sheet is disposed. . Furthermore, since it is not necessary to provide a prism sheet, the arrangement of the sheet can eliminate light attenuation (decrease in luminance) caused by the formed gap, and the light use efficiency as a planar illumination device, that is, The light emission efficiency can be made higher than when a prism sheet is arranged. Furthermore, since there is no need to provide a prism sheet, the apparatus can be made smaller (thinner).
  • the distance between the light exit surfaces becomes narrower, and it is composed of a pair of contour lines that intersect at the apex, and each contour line has a portion where the inclination angle with respect to a line perpendicular to the light exit surface changes.
  • a light guide plate having a shape in which the base end side (a pair of base end surfaces) of the parallel groove far from the apex has a sharper angle than the front end side (a pair of front end surfaces) close to the apex was used.
  • the side surfaces of the parallel grooves (a pair of tip surfaces)
  • the apex angle 0 should be 100 ° ⁇ ⁇ ⁇ 140 °
  • the prism formed on the light exit surface has an apex angle 0 of 40 ° ⁇ ⁇ ⁇ 70 °.
  • the apex angle ⁇ and apex angle ⁇ of the prism to be formed are within the above range.
  • the emission efficiency as the planar illumination device can be improved more suitably.
  • a light guide plate having a large light exit surface can be configured by arranging a plurality of light guide plates in parallel so that the light exit surfaces of the light guide plate all form the same plane.
  • the light guide plate is formed so that a smooth flat surface or curved surface is formed at the connecting portion between the inclined surface of a certain light guide plate and the inclined surface of the light guide plate adjacent thereto.
  • the inclination angle of the inclined surface can be adjusted. That is, the surface formed by the inclined surfaces of the adjacent light guide plates can be formed in an arch shape.
  • a knock light unit with a large light irradiation surface can be obtained, so it can be applied to a liquid crystal display device having a large display screen. it can. In particular, it can be suitably applied to a wall-mounted liquid crystal display device such as a wall-mounted television.
  • a reflector may be disposed on the side surface of the light guide plate disposed on the outermost side! /.
  • a reflector may be disposed on the side surface of the light guide plate disposed on the outermost side! /.
  • the reflecting plate can be formed using the same material as the reflecting sheet or reflector described above.
  • FIG. 13 is a diagram showing an outline of a tandem surface illumination device using the optical member of the present invention having a transmittance adjusting member and a diffusion film.
  • 13A is a perspective view of the surface lighting device
  • FIG. 13B is an enlarged cross-sectional view of the surface lighting device
  • FIG. 13C is a rear side force of the surface lighting device shown in FIG. 13A with the reflective sheet removed.
  • FIG. Note that the tandem-type planar lighting device has the same effect as the planar device shown in FIG. I was able to get it.
  • the tandem planar illumination device 210 includes a rod-shaped light source 122, a plurality of wedge-shaped light guide plates 210, a reflector 20, a reflection sheet 120, a transmittance adjusting member 28, a diffusion film 124, Prism sheets 16 and 17. As described above, here, the transmittance adjusting body 26 and the diffusion film 14 are collectively referred to as an optical member.
  • the rod-shaped light source 12 is a rod-shaped (linear) light source, and is used to illuminate a liquid crystal display panel (not shown).
  • the light source 12 is disposed in a parallel groove 18 f formed in the light guide plate 18.
  • a plurality of rod-shaped light sources 12 are used as a plurality of light guide plates 120 are connected and used. Each rod-shaped light source 12 is arranged between the light guide plate and the light guide plate adjacent to the light guide plate, with the longitudinal directions aligned in parallel.
  • rod-shaped light source 12 for example, a cold cathode tube, a fluorescent tube, an LED (light emitting diode), or the like can be used, as in the embodiment shown in FIG.
  • the light guide plate 120 includes a rectangular light exit surface 120a and an inclined back surface that is inclined with respect to the light exit surface 120a so that the thickness of one side of the light exit surface 120a decreases toward the opposite side.
  • a light incident surface 120b formed on a surface perpendicular to the light emission surface 120a and a surface including the opposite side and formed on a surface perpendicular to the light emission surface 120a.
  • the inclined back surface 120c may be a force curved surface forming a flat surface.
  • the cross section of the light guide plate 120 perpendicular to the longitudinal direction of the rod-shaped light source 12 is shaped so that the light incident surface 120b becomes narrower toward the wide end surface.
  • the plurality of light guide plates 120 are arranged by connecting the end face of the light guide plate adjacent to the light guide plates 120 and the light output surface 12 Oa of the light guide plate 120. Since the light exit surfaces of the respective light guide plates form the same plane, a light guide plate having a large size light exit surface can be configured.
  • the transmittance adjusting member 28 reduces unevenness in luminance of light emitted from the light guide plate 18, and includes a transparent film 29 which is an optical member having light transmittance, and a transparent film 29 having a predetermined density distribution. And a plurality of transmittance adjusting bodies 26 arranged on the surface of the substrate.
  • the transparent film 29 has a film shape and is disposed between the light guide plate 18 and the diffusion film 14.
  • the maximum size of the transmittance adjusting body is 500 m or less, and the dot size of the transmittance adjusting body 26 is so small that it is difficult to see.
  • the diffusion film 14 is an optical member for diffusing and making uniform the light emitted from the light exit surface 18a of the light guide plate 18.
  • the diffusing film 14 has optical characteristics in order to make the light emitted from the light exit surface 18a of the light guide plate 210 more uniform.
  • the optical properties of the diffusion film are set to 2.5 ° or more for a half-field angle, 90% or less for total light transmittance, or 85% or more for haze.
  • two or more of these optical characteristics may be combined.
  • the haze value may be set to 85% or more
  • the viewing half-value angle may be set to 2.5 ° or more.
  • the present invention is not limited to this, and similarly to the above-described planar lighting device 10, the maximum dimension of the transmittance adjusting body 26 is set to 500 m or less, and the maximum dimension of the transmittance adjusting body 26 is set to 500.
  • D the distance between the transmittance adjusting member 28 and the diffusion film 14
  • brightness unevenness can also be improved. That is, it is possible to reduce the uneven brightness while preventing the transmittance adjusting body from being visually recognized.
  • the reflection sheet 124 is disposed so as to cover the inclined back surface 120c of the light guide plate 120 and the rod-shaped light source 122.
  • the reflection sheet 124 reflects part of the light emitted from the rod-shaped light source 122 and makes it incident on the light guide plate 120, and improves the light use efficiency.
  • the reflection sheet 124 may be made of any material as long as it can reflect light.
  • the reflection sheet 124 can be formed of a resin sheet, a specular sheet, or the like.
  • the light that enters the light guide plate 210 from the light incident surface 120b is reflected by the inclined back surface 120c of the light guide plate 120 and then exits from the light exit surface 18a.
  • the light that does not directly enter the light guide plate 120 is reflected by the reflection sheet 124 formed so as to cover the rod-shaped light source 122, and the light of the light guide plate 120 It enters the interior and exits from the light exit surface 18a.
  • the light from the light guide plate 120 Light having a uniform brightness is emitted from the exit surface 120a.
  • a light guide plate having a large light emission surface by connecting a plurality of light guide plates 120 can be used in a backlight unit having a large light emission surface. Furthermore, this backlight unit can be applied to a liquid crystal display device having a large-sized display screen.
  • the light guide plate of the embodiment shown in FIG. 13 and the backlight unit using the light guide plate can be suitably applied particularly to a wall-mounted liquid crystal display device such as a wall-mounted television.
  • the optical member according to the present invention As described above, the optical member according to the present invention, the planar illumination device using the optical member, and the power explained in detail for the liquid crystal display device.
  • the present invention is not limited to the above-described embodiments. Various improvements and changes may be made without departing from the scope of the invention. Industrial applicability
  • the optical member of the present invention can reduce luminance unevenness without allowing the transmittance adjuster to be visually recognized. Therefore, it can be used as an optical member disposed on a light exit surface of a surface illumination device (backlight unit) used for a liquid crystal display, an overhead projector, an advertising signboard, and the like.
  • a surface illumination device backlight unit
  • planar lighting device of the present invention can be used as a planar lighting device (backlight unit) used for a liquid crystal display, an overhead projector, an electric signboard for advertisement, and the like.
  • liquid crystal display device of the present invention can be used for a liquid crystal monitor, a wall-mounted television, an advertising electric signboard, and the like.

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Abstract

Disclosed is an optical member improved in unevenness of luminance distribution. Specifically disclosed is an optical member wherein a transmittance-adjusting member, which is obtained by arranging a plurality of light transmittance adjusters on an optical base, and a diffusion film for uniformizing light by diffusion are arranged in layers. This optical member satisfies at least one of the following conditions: the ratio D/S of the distance D between the transmittance adjusters and the diffusion film to the maximum dimension S of the transmittance adjusters is not less than 3.0; the half-angle field of view of the diffusion film is not less than 2.5˚; the total light transmittance is not more than 90%; and the haze value is not less than 85%, and the maximum dimension S of the transmittance adjusters is set at not more than 500 μm.

Description

明 細 書  Specification
光学部材及びそれを用いた面状照明装置、並びに液晶表示装置 技術分野  Optical member, planar illumination device using the same, and liquid crystal display device
[0001] 本発明は、導光板の光射出面から出射される光をより均一な出射光とする光学部 材及びそれを用いた面状照明装置、並びに液晶表示装置に関する。  The present invention relates to an optical member that makes light emitted from a light exit surface of a light guide plate more uniform outgoing light, a planar illumination device using the same, and a liquid crystal display device.
背景技術  Background art
[0002] 液晶表示装置には、液晶パネル (LCD)の裏面側力 光を照射し、液晶パネルを 照明するバックライトユニットが用いられている。バックライトユニットは、照明用の光源 、この光源力 出射した光を拡散して液晶パネルを照射する導光板、導光板から放 射される光を均一化するプリズムシートや拡散シートなどの部品を用いて構成される 近年、液晶表示装置の薄型化、低消費電力化が要望されており、それを実現する ために種々の形状の導光板が提案されている（例えば、特開平 9— 304623号公報 、特開平 8— 62426号公報及び特開平 10— 133027号公報参照)。  A liquid crystal display device uses a backlight unit that illuminates the liquid crystal panel by irradiating the back side of the liquid crystal panel (LCD). The backlight unit uses components such as a light source for illumination, a light guide plate that diffuses the emitted light and irradiates the liquid crystal panel, and a prism sheet and a diffusion sheet that uniformize the light emitted from the light guide plate. In recent years, there has been a demand for thinning and low power consumption of liquid crystal display devices, and various shapes of light guide plates have been proposed in order to achieve this (for example, Japanese Patent Laid-Open No. 9-304623). JP-A-8-62426 and JP-A-10-133027).
[0003] 特開平 9— 304623号公報には、導光板を用いた面光源装置が記載されている。 [0003] JP-A-9-304623 discloses a surface light source device using a light guide plate.
図 14は、特開平 9— 304623号公報に記載の面光源装置の分解斜視図である。 同図に示す面光源装置 (バックライトユニット）は、導光板 100に蛍光ランプ 102を 埋め込んだ後、導光板 100の背面に反射シート 104を配置し、導光板 100の光射出 面に透過光量補正シート 106、光拡散板 108、プリズムシート 110を積層することで 形成される。  FIG. 14 is an exploded perspective view of the surface light source device described in JP-A-9-304623. In the surface light source device (backlight unit) shown in the figure, after the fluorescent lamp 102 is embedded in the light guide plate 100, the reflection sheet 104 is disposed on the back surface of the light guide plate 100, and the transmitted light amount is corrected on the light exit surface of the light guide plate 100. It is formed by laminating a sheet 106, a light diffusion plate 108, and a prism sheet 110.
導光板 100は、略長方形形状を有し、照明光を拡散する微粒子が分散混入された 榭脂により形成されている。また、導光板 100の上面は平坦になっており、光射出面 として割り当てられる。さらに、導光板 100の背面 (光射出面と反対側の面）には蛍光 ランプ 102を埋め込む断面 U字状の溝 100aが形成され、導光板 100の光射出面に は、蛍光ランプ 102の真上を避けて、照明光の出射を促す光量補正面 100bが形成 されている。  The light guide plate 100 has a substantially rectangular shape and is formed of a resin in which fine particles that diffuse illumination light are dispersed and mixed. Further, the upper surface of the light guide plate 100 is flat, and is assigned as a light exit surface. Further, a U-shaped groove 100a for embedding the fluorescent lamp 102 is formed on the back surface of the light guide plate 100 (the surface opposite to the light emitting surface). The light emitting surface of the light guide plate 100 has a true shape of the fluorescent lamp 102. A light amount correction surface 100b that avoids the top and promotes the emission of illumination light is formed.
[0004] 特開平 9— 304623号公報には、微粒子を混入して導光板 100を形成すると共に、 蛍光ランプ 102の真上を除いた光射出面の一部または全部に形成した光量補正面 100bにより照明光の出射を促すことにより、全体の厚さを薄型化し、かつ出射光の 不自然な輝度むらを低減できる（図 15参照)ことが記載されている。 [0004] JP-A-9-304623 discloses that a light guide plate 100 is formed by mixing fine particles, The light intensity correction surface 100b formed on part or all of the light exit surface except directly above the fluorescent lamp 102 encourages the emission of illumination light, thereby reducing the overall thickness and unnatural brightness of the emitted light. It is described that unevenness can be reduced (see FIG. 15).
[0005] また、特開平 8— 62426号公報には、ノ ックライトの照射量を減らすことなぐ液晶 表示装置の小型軽量化や薄型化及びコスト'消費電力の低減化を実現することがで きる液晶表示装置のバックライトを得るために、長方形の照射面と、短辺の中央部に 長辺と平行にくり抜かれた、光源を嵌挿するための矩形断面の溝と、この溝を挟んで 長辺の両側面方向に向かって板厚が次第に薄くなるように形成された背面とを有す る導光板が記載されている。  [0005] Further, Japanese Patent Application Laid-Open No. 8-62426 discloses a liquid crystal display that can reduce the size and weight of a liquid crystal display device and reduce the power consumption without reducing the amount of knocklight irradiation. In order to obtain a backlight of the display device, a rectangular irradiation surface, a rectangular cross section grooved in parallel to the long side at the center of the short side, and a long section across the groove are inserted. There is described a light guide plate having a back surface formed so that the plate thickness gradually decreases toward both side surfaces of the side.
また、特開平 10— 133027号公報には、液晶表示装置の額縁を狭くし、厚みを薄 くすることができ、光利用効率がよく明るいバックライトユニットを得るために、光源を 配置するための凹部の幅方向に平行な断面の形状が、深さ方向を主軸とする放物 線形状である導光体 (導光板）が記載されて 、る。  Japanese Patent Application Laid-Open No. 10-133027 discloses a liquid crystal display device in which the frame can be narrowed, the thickness can be reduced, and a light source can be arranged in order to obtain a bright backlight unit with high light utilization efficiency. A light guide (light guide plate) is described in which the shape of the cross section parallel to the width direction of the recess is a parabolic shape with the depth direction as the main axis.
[0006] このような導光板を用いたバックライトユニットでは、輝線、暗線など輝度むらを十分 に解消できてはいない。そこで、輝度分布のむらを改善するための種々の技術が提 案されている（例えば、特開平 5— 127156号公報、特開平 6— 235825号公報、特 開 2001— 42327号公報及び特開 2004— 170698号公報参照）。  [0006] In a backlight unit using such a light guide plate, luminance unevenness such as bright lines and dark lines cannot be sufficiently eliminated. Therefore, various techniques for improving the unevenness of the luminance distribution have been proposed (for example, JP-A-5-127156, JP-A-6-235825, JP2001-42327, and JP2004- No. 170698).
[0007] 特開平 5— 127156号公報には、拡散板の表面に光透過を阻止するドッド上の印 刷部を形成することが記載されている。さらに、その印刷部の密度を冷陰極蛍光灯が 直下に位置付けられる領域において密にし、該領域力 遠ざかるにつれ疎にするこ とにより、拡散板側に放出される光量は、該拡散板の全面にいたって均一となると記 載されている。  [0007] Japanese Patent Application Laid-Open No. 5-127156 describes that a printing portion on a dod for preventing light transmission is formed on the surface of a diffusion plate. Further, the density of the printed portion is made dense in the region where the cold cathode fluorescent lamp is located immediately below, and the amount of light emitted to the diffusion plate side is reduced over the entire surface of the diffusion plate by making the printing area sparse as the area force is moved away. It is written that it will be uniform.
[0008] 特開平 6— 235825号公報には、板体の下面に線光源力も遠ざかるにつれて面積 率が大きくなるように光散乱層が形成されて 、る導光板が記載されて 、る。光散乱層 は、線光源からの輝度変化に応じて導光板の板体内部の光を上面から取り出すため に用いるものであることが記載されて 、る。  Japanese Patent Laid-Open No. 6-235825 describes a light guide plate in which a light scattering layer is formed on the lower surface of a plate so that the area ratio increases as the linear light source force increases. It is described that the light scattering layer is used for extracting light inside the plate of the light guide plate from the upper surface in accordance with the luminance change from the line light source.
[0009] 特開 2001— 42327号公報〖こは、線状光源の光源光量に反比例することによって その直射による輝度上昇を抑制するように透明基板の長手方向に添う帯状にして、 高反射性インクにより印刷した密度変調のドットパターンをなす透過調整手段が記載 されている。このとき該ドットの密度変調パターンは、これを、上記突出縁部の端縁か ら面内方向にドット面積又はドット数を減少変化したものとしてあることも記載されてい る。 [0009] Japanese Patent Application Laid-Open Publication No. 2001-42327 is a strip that follows the longitudinal direction of the transparent substrate so as to suppress an increase in luminance due to direct light by being inversely proportional to the light source amount of the linear light source, A transmission adjusting means is described which forms a density-modulated dot pattern printed with highly reflective ink. At this time, it is also described that the density modulation pattern of the dots is obtained by reducing the dot area or the number of dots in the in-plane direction from the edge of the protruding edge.
これによつて線状光源の光源光は、各突出縁部を介してその表面の出光面に形成 した透過調整手段に至り、その密度変調によって透過量と透過防止量とを、突出縁 部の端縁側力 面内方向に漸増するように調整して、光源光の直射による線状光源 を配置する部分の輝度上昇を抑止して、上記導光手段による導光の照明輝度との均 一性を確保して 、ると記載されて 、る。  As a result, the light source light of the linear light source reaches the transmission adjusting means formed on the light emitting surface of the surface through each protruding edge, and the amount of transmission and the amount of transmission prevention are reduced by the density modulation. Edge side force Adjust to increase gradually in the in-plane direction, suppress the increase in brightness of the part where the linear light source is placed due to direct light source light, and uniformity with the light guide illumination brightness by the light guide means It is stated that it is secured.
[0010] 特開 2004— 170698号公報には、バックライトユニットの光出射面の少なくとも輝 度分布を測定したデータを階調反転させて形成された輝度分布反転像が印刷され ている、液晶表示装置のバックライトユニットに使用される光学部材である光拡散シ ートが記載されている。  [0010] Japanese Patent Application Laid-Open No. 2004-170698 discloses a liquid crystal display on which a luminance distribution inversion image formed by reversing gradation of data obtained by measuring at least the luminance distribution of the light exit surface of a backlight unit is printed. A light diffusion sheet which is an optical member used in the backlight unit of the apparatus is described.
この輝度分布反転像は、ノ ックライトユニットの光出射面の輝度分布を反映した高 精度のグラデーションパターンを備えているため、導光板の出射光は光拡散シートを 透過した後は、輝度ムラの少ない状態となり、輝線の発生が防止されることが記載さ れている。  This inverted luminance distribution image has a high-precision gradation pattern that reflects the luminance distribution on the light exit surface of the knocklight unit, so that the light emitted from the light guide plate is not uneven in brightness after passing through the light diffusion sheet. It is described that the number of emission lines is reduced and generation of bright lines is prevented.
[0011] 特許文献 1 :特開平 9 304623号公報  Patent Document 1: Japanese Patent Laid-Open No. 9 304623
特許文献 2：特開平 8— 62426号公報  Patent Document 2: JP-A-8-62426
特許文献 3 :特開平 10— 133027号公報  Patent Document 3: JP-A-10-133027
特許文献 4：特開平 5 - 127156号公報  Patent Document 4: JP-A-5-127156
特許文献 5：特開平 6 - 235825号公報  Patent Document 5: JP-A-6-235825
特許文献 6：特開 2001—42327号公報  Patent Document 6: Japanese Patent Laid-Open No. 2001-42327
特許文献 7：特開 2004— 170698号公報  Patent Document 7: Japanese Unexamined Patent Application Publication No. 2004-170698
発明の開示  Disclosure of the invention
発明が解決しょうとする課題  Problems to be solved by the invention
[0012] しカゝしながら、上述の特開平 5— 127156号公報、特開平 6— 235825号公報、特 開 2001— 42327号公報及び特開 2004— 170698号公報には、透過率を調整す るドット (透過率調整体)や、そのドットのパターン形状について詳細に開示されてい ない。そこで、通常の印刷方法で透過率を調整するためのドット (透過率調整体)を 作成したが、均質な光源を得ることができなカゝつた。 However, in the above-mentioned JP-A-5-127156, JP-A-6-235825, JP2001-42327 and JP2004-170698, the transmittance is adjusted. The details of the dot (transmittance adjusting body) and the pattern shape of the dot are not disclosed. Therefore, we created dots (transmittance adjusters) for adjusting the transmittance with the normal printing method, but we were unable to obtain a homogeneous light source.
[0013] 本発明は、力かる実情に鑑みてなされたものであり、輝度分布のむらを改善するこ とができる光学部材及びそれを用いた面状照明装置並びに液晶表示装置を提供す ることを目的とする。  [0013] The present invention has been made in view of the strong situation, and provides an optical member that can improve unevenness of luminance distribution, a planar illumination device using the same, and a liquid crystal display device. Objective.
課題を解決するための手段  Means for solving the problem
[0014] 本発明の第 1の態様の第 1の形態は、光の透過率を調整する複数の透過率調整体 を光学部材の表面に配置してなる透過率調整部材と、光を拡散して均一化する拡散 フィルムとを積層してなる光学部材であって、前記透過率調整体の最大寸法が 500 m以下であり、かつ前記拡散フィルムの視野半値角が 2. 5° 以上である光学部材 を提供する。 [0014] In a first form of the first aspect of the present invention, a transmittance adjusting member in which a plurality of transmittance adjusting bodies for adjusting the transmittance of light are arranged on the surface of the optical member, and light is diffused. An optical member formed by laminating a diffusion film that is uniformized in an optical manner, wherein the maximum dimension of the transmittance adjusting body is 500 m or less, and the viewing half-value angle of the diffusion film is 2.5 ° or more. Providing a member.
ここで、前記拡散フィルムは、ヘイズ値が 85%以上であることが好ましい。 本発明の第 1の態様の第 2の形態は、光の透過率を調整する複数の透過率調整体 を光学部材の表面に配置してなる透過率調整部材と、光を拡散して均一化する拡散 フィルムとを積層してなる光学部材であって、前記透過率調整体の最大寸法が 500 μ m以下であり、かつ前記拡散フィルムの全光線透過率が 90%以下である光学部 材を提供する。  Here, the diffusion film preferably has a haze value of 85% or more. The second form of the first aspect of the present invention is a transmittance adjusting member formed by arranging a plurality of transmittance adjusting bodies for adjusting the light transmittance on the surface of the optical member, and diffusing and uniformizing the light. An optical member formed by laminating a diffusing film, wherein a maximum dimension of the transmittance adjusting body is 500 μm or less and a total light transmittance of the diffusing film is 90% or less. provide.
本発明の第 1の態様の第 3の形態は、光の透過率を調整する複数の透過率調整体 を光学部材の表面に配置してなる透過率調整部材と、光を拡散して均一化する拡散 フィルムとを積層してなる光学部材であって、前記透過率調整体の最大寸法が 500 μ m以下であり、かつ前記拡散フィルムのヘイズ値が 85%以上である光学部材を提 供する。  According to a third aspect of the first aspect of the present invention, there is provided a transmittance adjusting member formed by arranging a plurality of transmittance adjusting bodies for adjusting the light transmittance on the surface of the optical member, and diffusing and uniformizing the light. There is provided an optical member obtained by laminating a diffusion film to be laminated, wherein a maximum dimension of the transmittance adjusting body is 500 μm or less and a haze value of the diffusion film is 85% or more.
本発明の第 1の態様の第 4の形態は、光の透過率を調整する複数の透過率調整体 を光学部材の表面に配置してなる透過率調整部材と、光を拡散して均一化する拡散 フィルムとが積層されてなる光学部材であって、前記透過率調整体の最大寸法 Sが 5 00 m以下であり、かつ前記透過率調整体と前記拡散フィルムとの距離 Dと、前記 透過率調整体の最大寸法 Sとの比率 DZSが 3. 0以上である光学部材を提供する。 [0015] 本発明の第 2の態様の第 1の形態は、第 1の態様の光学部材と、光源と、前記光源 力 放射される光を矩形状の平面力 前記光学部材に向けて出射する導光板とを備 える面状照明装置を提供する。 According to a fourth aspect of the first aspect of the present invention, there is provided a transmittance adjusting member in which a plurality of transmittance adjusting bodies that adjust light transmittance are arranged on the surface of an optical member, and light is diffused and uniformized An optical member formed by laminating a diffusion film, wherein a maximum dimension S of the transmittance adjusting body is 500 m or less, and a distance D between the transmittance adjusting body and the diffusion film, and the transmission Provided is an optical member having a ratio DZS of 3.0 or more with the maximum dimension S of the rate adjuster. [0015] In a first form of the second aspect of the present invention, the optical member of the first aspect, a light source, and the light source force radiate the emitted light toward the rectangular planar force toward the optical member. Provided is a planar lighting device including a light guide plate.
本発明の第 2の態様の第 2の形態は、第 1の態様の光学部材と、光源と、前記光源 力 放射される光を矩形状の平面力 前記光学部材に向けて出射する導光板とを備 え、前記光学部材は光透過性を有する透明フィルムである面状照明装置を提供する 本発明の第 2の態様の第 3の形態は、第 1の態様の光学部材と、光源とを備え、前 記光学部材は前記光源から放射される光を矩形状の平面から前記光学部材に向け て出射する導光板導光板であり、前記透過率調整体は導光板の光射出面上に配置 される面状照明装置を提供する。  The second form of the second aspect of the present invention is the optical member of the first aspect, a light source, and a light guide plate that emits light emitted from the light source force toward the optical member in a rectangular plane force. The third aspect of the second aspect of the present invention provides the optical member of the first aspect and a light source. The optical member is a light guide plate light guide plate that emits light emitted from the light source from a rectangular plane toward the optical member, and the transmittance adjusting body is disposed on a light exit surface of the light guide plate Provided is a planar lighting device.
[0016] 前記導光板は、矩形状光射出面と、その一辺に略平行で矩形状光射出面の略中 央部に位置する厚肉部と、前記厚肉部に略平行に形成される 1対の薄肉端部と、前 記厚肉部の略中央で、前記矩形状光射出面と逆側に、前記一辺と略平行に形成さ れ、棒状光源を収納するための平行溝と、前記厚肉部から前記一辺に略直交する方 向に両側の前記 1対の前記薄肉端部のそれぞれに向かって肉厚が薄くなり、前記平 行溝の両側にそれぞれ 1対の傾斜背面を形成する 1対の傾斜背面部とを有し、前記 平行溝は、前記直交方向の断面形状において、前記矩形状光射出面に向かって、 その間隔が狭くなり、頂点で交わる 1対の輪郭線で構成され、前記直交方向の断面 形状における前記平行溝の各輪郭線は、前記矩形状光射出面に垂直な線に対する 傾斜角度が変化する部分を有し、前記頂点に近い先端側より、前記頂点から遠い前 記平行溝の基端側の方が鋭角となることが好ま 、。 [0016] The light guide plate is formed to have a rectangular light exit surface, a thick portion that is substantially parallel to one side of the light guide plate and located at a substantially central portion of the rectangular light exit surface, and substantially parallel to the thick portion. A pair of thin end portions, a parallel groove for accommodating a rod-shaped light source, formed substantially parallel to the one side on the opposite side of the rectangular light exit surface at the approximate center of the thick portion; The thickness decreases from the thick portion toward each of the pair of thin end portions on both sides in a direction substantially perpendicular to the one side, and a pair of inclined back surfaces are formed on both sides of the parallel groove. A pair of inclined back surface portions, and the parallel grooves are formed by a pair of contour lines intersecting at the apexes with a narrower interval toward the rectangular light exit surface in the cross-sectional shape in the orthogonal direction. And each contour line of the parallel groove in the cross-sectional shape in the orthogonal direction is inclined with respect to a line perpendicular to the rectangular light exit surface. Has a portion angle is changed, from the front end side closer to the apex, towards the base end side of the distant prior Symbol parallel grooves from the apex preferred that an acute angle.
あるいは、前記導光板は、矩形状の光射出面と、前記光射出面の一辺からその対 辺に向かうに従って板厚が薄くなるように、前記光射出面に対して傾斜する傾斜背面 と、前記一辺を含む面であり、前記光射出面に垂直な面に形成される光入射面と、 前記対辺を含む面であり、前記光射出面に垂直な面に形成される端面とを有するこ とが好ましい。  Alternatively, the light guide plate includes a rectangular light emission surface and an inclined back surface that is inclined with respect to the light emission surface so that the plate thickness decreases from one side of the light emission surface toward the opposite side; A light incident surface formed on a surface perpendicular to the light emission surface, and an end surface formed on a surface perpendicular to the light emission surface and perpendicular to the light emission surface. Is preferred.
[0017] 本発明の第 3の態様は、第 2の態様の面状照明装置力もなるバックライトユニットと、 このノ ックライトユニットの光出射面側に配置される液晶表示パネルと、前記バックラ イトユニット及び前記液晶表示パネルを駆動する駆動ユニットとを有する液晶表示装 置を提供する。 [0017] A third aspect of the present invention is a backlight unit that also has the surface illumination device power of the second aspect; Provided is a liquid crystal display device having a liquid crystal display panel disposed on the light emission surface side of the knock light unit, and the backlight unit and a drive unit for driving the liquid crystal display panel.
発明の効果  The invention's effect
[0018] 本発明に従えば、透過率調整体の最大寸法と拡散フィルムの光学特性について規 定することで、透過率調整体が視認されることを防止でき、輝度を低減させることなく 、輝度分布のむらを改善することができる光学部材及びそれを用いた面状照明装置 並びに液晶表示装置を提供することができる。  [0018] According to the present invention, by defining the maximum dimension of the transmittance adjusting body and the optical characteristics of the diffusion film, the transmittance adjusting body can be prevented from being visually recognized, and the brightness can be reduced without reducing the brightness. An optical member capable of improving unevenness of distribution, a planar illumination device using the same, and a liquid crystal display device can be provided.
[0019] また、本発明に従えば、透過率調整体の最大寸法 S、及び透過率調整体と拡散フ イルムとの距離 Dにつ ヽて規定することで、透過率調整体が視認されることを防止で き、輝度分布のむらを改善することができる光学部材及びそれを用いた面状照明装 置、並びに液晶表示装置を提供することができる。  [0019] Further, according to the present invention, the transmittance adjusting body is visually recognized by defining the maximum dimension S of the transmittance adjusting body and the distance D between the transmittance adjusting body and the diffusion film. Thus, it is possible to provide an optical member capable of preventing this problem and improving unevenness in luminance distribution, a planar illumination device using the same, and a liquid crystal display device.
さらに、輝度を低減させることなぐ輝度分布のむらを低減させることもできる。 図面の簡単な説明  Furthermore, the unevenness of the luminance distribution without reducing the luminance can be reduced. Brief Description of Drawings
[0020] [図 1]図 1は、本発明の光学部材を用いた面状照明装置を有する液晶表示装置の概 略を示す構成図である。  FIG. 1 is a configuration diagram showing an outline of a liquid crystal display device having a planar illumination device using the optical member of the present invention.
[図 2]図 2は、視認限界値を決定するために使用したバックライトユニットの概略を示 す断面図である。  [FIG. 2] FIG. 2 is a cross-sectional view showing an outline of the backlight unit used for determining the visual recognition limit value.
[図 3]図 3は、透過率調整体が視認される場合の明度 Bとその変化率 dB/dxを示す図 である。  [FIG. 3] FIG. 3 is a diagram showing lightness B and the rate of change dB / dx when the transmittance adjusting body is visually recognized.
[図 4]図 4は、透過率調整体が視認されない場合の明度 Bとその変化率 dB/dxを示 す図である。  [FIG. 4] FIG. 4 is a diagram showing brightness B and its change rate dB / dx when the transmittance adjusting body is not visually recognized.
[図 5]図 5Aは、反射シートと導光板の傾斜面との間にプリズムシートが配置されてい る様子を示す概略断面図であり、図 5Bは、反射シートと導光板の傾斜面との間に配 置されているプリズムシートを導光板側から見た概略平面図であり、図 5Cは、プリズ ムシートの概略横断面図である。  FIG. 5A is a schematic cross-sectional view showing a state in which a prism sheet is disposed between the reflective sheet and the inclined surface of the light guide plate, and FIG. 5B is a schematic view of the reflective sheet and the inclined surface of the light guide plate. FIG. 5C is a schematic plan view of the prism sheet disposed therebetween as seen from the light guide plate side, and FIG. 5C is a schematic cross-sectional view of the prism sheet.
[図 6]図 6Aは、平行溝の 1対の先端面の長さ方向に垂直な断面形状が双曲線の導 光板の平行溝周辺の概略断面図であり、図 6Bは、平行溝の 1対の先端面の長さ方 向に垂直な断面形状が楕円形の導光板の平行溝周辺の概略断面図であり、図 6C は、平行溝の 1対の先端面の長さ方向に垂直な断面形状が、平行溝の中心を通り導 光板の光射出面に垂直な中心線に対して対称な 2つの円弧曲線の一部力 形成さ れている導光板の平行溝周辺の概略断面図であり、図 6Dは、平行溝の 1対の先端 面の長さ方向に垂直な断面形状が、平行溝の中心を通り導光板の光射出面に垂直 な中心線に対して対称な 2つの放物線の一部力 形成されている導光板の平行溝 周辺の概略断面図である。 [FIG. 6] FIG. 6A is a schematic cross-sectional view around the parallel groove of the light guide plate having a hyperbolic cross-sectional shape perpendicular to the length direction of the pair of front end surfaces of the parallel groove, and FIG. 6B is a pair of parallel grooves. Length of tip 6C is a schematic cross-sectional view of the periphery of the parallel groove of the light guide plate having an elliptical cross-sectional shape, and FIG. Fig. 6D is a schematic cross-sectional view around the parallel groove of the light guide plate formed by partial force of two circular arc curves symmetrical to the center line perpendicular to the light exit surface of the light guide plate. The cross-sectional shape perpendicular to the longitudinal direction of the pair of tip surfaces of the pair is formed by partial forces of two parabolas symmetrical to the center line passing through the center of the parallel groove and perpendicular to the light exit surface of the light guide plate. It is a schematic sectional drawing of the parallel groove periphery of a light-guide plate.
[図 7]図 7Aは、平行溝の 1対の先端面の長さ方向に垂直な断面形状が、平行溝の中 心に向力つて凸の 2つの曲線力も形成されている導光板の平行溝周辺の概略断面 図であり、図 7Bは、平行溝の 1対の先端面の長さ方向に垂直な断面形状が、平行溝 の中心に向力つて凸の曲線と凹の曲線を組み合わせた曲線力も形成されている導 光板の平行溝周辺の概略断面図である。  [FIG. 7] FIG. 7A shows a parallel shape of a light guide plate in which a cross-sectional shape perpendicular to the length direction of a pair of front end surfaces of parallel grooves forms two curved forces that are convex toward the center of the parallel grooves. Fig. 7B is a schematic cross-sectional view of the periphery of the groove. Fig. 7B shows a combination of a convex curve and a concave curve with a cross-sectional shape perpendicular to the length direction of the pair of tip surfaces of the parallel groove. FIG. 6 is a schematic cross-sectional view around a parallel groove of a light guide plate in which a curved force is also formed.
[図 8]図 8Aは、平行溝の 1対の基端面の長さ方向に垂直な断面形状が、 1対の先端 面よりも鋭角な線分で形成されている導光板の平行溝周辺の概略断面図であり、図 8Bは、平行溝の 1対の基端面の長さ方向に垂直な断面形状が、平行溝の中心に向 かって凹状の曲線で形成された導光板の平行溝周辺の概略断面図である。  [FIG. 8] FIG. 8A is a cross-sectional view perpendicular to the length direction of a pair of base end faces of parallel grooves formed around a line segment having a sharper angle than the pair of front end faces. FIG. 8B is a schematic cross-sectional view, and FIG. 8B is a cross-sectional view perpendicular to the length direction of a pair of base end surfaces of the parallel grooves formed around the parallel grooves of the light guide plate formed by a concave curve toward the center of the parallel grooves. It is a schematic sectional drawing.
[図 9]図 9は、本発明に好適に用いることができる導光板の他の一例を示す概略断面 図である。 FIG. 9 is a schematic cross-sectional view showing another example of a light guide plate that can be suitably used in the present invention.
[図 10]図 10は、導光板の光射出面側に形成される網点パターンの例である。  FIG. 10 is an example of a halftone dot pattern formed on the light exit surface side of the light guide plate.
[図 11]図 11 Aは、導光板の傾斜面にプリズムが形成されて ヽる様子を示す概略断面 図であり、図 11Bは、プリズムが形成されている導光板の傾斜面を光射出面側から見 た概略平面図である。 FIG. 11A is a schematic cross-sectional view showing a state in which a prism is formed on an inclined surface of a light guide plate, and FIG. 11B shows a light exit surface of the inclined surface of the light guide plate on which the prism is formed. It is a schematic plan view seen from the side.
[図 12]図 12は、導光板の傾斜面及び光射出面にプリズムが形成されている様子を示 す概略断面図である。  FIG. 12 is a schematic cross-sectional view showing a state in which prisms are formed on the inclined surface and the light exit surface of the light guide plate.
[図 13]図 13は、本発明の光学部材を用いたタンデム方式の面状照明装置の概略を 示す図である。  FIG. 13 is a diagram showing an outline of a tandem type planar illumination device using the optical member of the present invention.
[図 14]図 14は、従来の導光板を有する面光源装置の概略斜視図である。  FIG. 14 is a schematic perspective view of a surface light source device having a conventional light guide plate.
[図 15]図 15は、図 14に示す面光源装置の導光板の出射面における輝度のグラフで ある。 [FIG. 15] FIG. 15 is a graph of luminance on the exit surface of the light guide plate of the surface light source device shown in FIG. is there.
符号の説明  Explanation of symbols
[0021] 2 バックライトユニット  [0021] 2 Backlight unit
4 液晶表示パネル  4 LCD panel
6 駆動ユニット  6 Drive unit
10 液晶表示装置  10 Liquid crystal display
12 光源  12 Light source
14 拡散フィルム  14 Diffusion film
16、 17、 19 プリズムシー卜  16, 17, 19
18 導光板  18 Light guide plate
18a 光射出面  18a Light exit surface
18b 厚肉部  18b Thick part
18c 薄肉端部  18c Thin end
18d 傾斜面  18d inclined surface
18e 傾斜背面部  18e Inclined back
18f 平行溝  18f parallel groove
20 リフレクタ  20 Reflector
22 反射シート  22 Reflective sheet
24 反射板  24 reflector
26 透過率調整体  26 Transmittance adjuster
28 透過率調整部材  28 Transmittance adjustment member
29 透明フィルム  29 Transparent film
発明を実施するための最良の形態  BEST MODE FOR CARRYING OUT THE INVENTION
[0022] 本発明に係る光学部材を用いた面状照明装置並びに液晶表示装置について、添 付の図面に示す実施形態を基に詳細に説明する。 [0022] A planar illumination device and a liquid crystal display device using an optical member according to the present invention will be described in detail based on embodiments shown in the accompanying drawings.
図 1は、本発明の光学部材を用いた面状照明装置を有する液晶表示装置の概略 を示す図である。図 1 Aは液晶表示装置の斜視図であり、図 1Bは図 1 Aに示す液晶 表示装置の断面図である。 液晶表示装置 10は、基本的に、面状照明装置 (以下、バックライトユニットともいう） 2と、バックライトユニット 2の光射出面側に配置される液晶表示パネル 4と、それらを 駆動する駆動ユニット 6とを有する。 FIG. 1 is a diagram showing an outline of a liquid crystal display device having a planar illumination device using the optical member of the present invention. 1A is a perspective view of the liquid crystal display device, and FIG. 1B is a cross-sectional view of the liquid crystal display device shown in FIG. 1A. The liquid crystal display device 10 basically includes a planar illumination device (hereinafter also referred to as a backlight unit) 2, a liquid crystal display panel 4 disposed on the light emission surface side of the backlight unit 2, and a drive for driving them. With unit 6.
液晶表示パネル 4は、予め特定の方向に配列してある液晶分子に、部分的に電界 を印加してこの分子の配列を変え、液晶セル内に生じた屈折率の変化を利用して、 液晶表示パネル 4の表面上に文字、図形、画像などを表示する。  The liquid crystal display panel 4 applies a partial electric field to liquid crystal molecules arranged in a specific direction in advance to change the arrangement of the molecules, and utilizes the change in the refractive index generated in the liquid crystal cell. Characters, figures, images, etc. are displayed on the surface of the display panel 4.
駆動ユニット 6は、液晶表示パネル 4内の透明電極に電圧をかけ、液晶分子の向き を変えて液晶表示パネル 4を透過する光の透過率を制御したりする。  The drive unit 6 applies a voltage to the transparent electrode in the liquid crystal display panel 4 to change the direction of the liquid crystal molecules to control the transmittance of light transmitted through the liquid crystal display panel 4.
[0023] バックライトユニット 2は、液晶表示パネル 4の背面から、液晶表示パネル 4の全面に 光を照射する装置であり、液晶表示パネル 4の画像表示面と略同一の光射出面 (発 光面)を有する。 [0023] The backlight unit 2 is a device that irradiates light from the back of the liquid crystal display panel 4 to the entire surface of the liquid crystal display panel 4. The backlight unit 2 is substantially the same light emission surface (light emitting surface) as the image display surface of the liquid crystal display panel 4. Surface).
ノ ックライトユニット 2は、図 1に示すように、基本的には、光源 12と、導光板 18と、リ フレクタ 20と、反射シート 22と、透過率調整部材 28と、拡散フィルム 14と、プリズムシ ート 16, 17とを有する。なお、導光板 18からの出射光を均一にするために、透明フィ ルム 29上に配置される透過率調整体 26と、拡散フィルム 14と、プリズムシート 16, 1 7とが積層されている力 透過率調整体 26と拡散フィルム 14とを併せて光学部材とい  As shown in FIG. 1, the knock light unit 2 basically includes a light source 12, a light guide plate 18, a reflector 20, a reflection sheet 22, a transmittance adjusting member 28, a diffusion film 14, Prism sheets 16 and 17. In order to make the light emitted from the light guide plate 18 uniform, the force with which the transmittance adjusting body 26 arranged on the transparent film 29, the diffusion film 14, and the prism sheets 16, 17 are laminated. The transmittance adjusting body 26 and the diffusion film 14 are collectively referred to as an optical member.
[0024] 光源 12は、棒状 (線状)光源であり、液晶表示パネル 4を照明するために用いられ る。光源 12は、導光板 18に形成された平行溝 18f内に配置される。 The light source 12 is a rod-like (linear) light source and is used to illuminate the liquid crystal display panel 4. The light source 12 is disposed in a parallel groove 18 f formed in the light guide plate 18.
棒状光源 12としては、例えば、冷陰極管、蛍光管、 LED (発光ダイオード)などを用 いることがでさる。  As the rod-shaped light source 12, for example, a cold cathode tube, a fluorescent tube, an LED (light emitting diode) or the like can be used.
光源力LEDの場合には、導光板 18の平行溝 18fと同等の長さを有する円柱状又 は角柱状の透明な導光体を用い、その導光体の側面に LEDを配置して用いる。この ような LED光源は、用いた導光体の側面力 LEDの光を入射してその導光体の上 面及び底面力 光を出射することができる。  In the case of a light source power LED, a cylindrical or prismatic transparent light guide having a length equivalent to the parallel groove 18f of the light guide plate 18 is used, and the LED is disposed on the side of the light guide. . Such an LED light source is capable of emitting light from the side force LED of the light guide used and emitting light from the top and bottom surfaces of the light guide.
[0025] 導光板 18は、矩形状の光射出面 18aと、その一辺に平行な厚肉部 18bと、この厚 肉部 18bの両側に前記一辺に平行に形成される一対の薄肉端部 18cと、厚肉部 18 bから前記一辺に直行する方向に両側の薄肉端部 18cに向力つて肉厚が薄くなり、 傾斜面 18dを形成する 1対の傾斜背面部 18eと、肉厚部 18bに前記一辺に平行に形 成される光源 12を収納するための平行溝 18fとを有する。 [0025] The light guide plate 18 includes a rectangular light exit surface 18a, a thick portion 18b parallel to one side thereof, and a pair of thin end portions 18c formed on both sides of the thick portion 18b in parallel to the one side. Then, the thickness is reduced by directing the thin end portions 18c on both sides in the direction perpendicular to the one side from the thick portion 18b, A pair of inclined back surface portions 18e forming the inclined surface 18d, and a parallel groove 18f for accommodating the light source 12 formed in parallel with the one side in the thick portion 18b.
すなわち、導光板 18は、一方の面が平坦となって光射出面 18aを構成しており、他 方の面が、厚肉部 18bから両側に、一方の辺に向力 にしたがって板厚が薄くなるよ うに、一方の面に対して傾斜して 1対の傾斜面 18dを構成する。ここでは、傾斜面 18 dを平面として形成する力 曲面としてもよい。  In other words, the light guide plate 18 has a flat surface on one side to form a light emission surface 18a, and the other surface has a plate thickness according to the direction of force on one side from the thick wall portion 18b. A pair of inclined surfaces 18d are formed so as to be thinner with respect to one surface. Here, it is good also as a force curved surface which forms the inclined surface 18d as a plane.
また、導光板 18は、他方の面において、傾斜面 18dと基端面 18iとの間に光射出 面 18aに平行な平行面 18gを有する。すなわち、この導光板 18の厚肉部 18bにおい ては、傾斜面 18dから延在する平行面 18gが設けられる。このような平行面 18gは、 必ずしも設ける必要はないが、光の利用効率を向上させることができるので、設ける のが好ましい。  The light guide plate 18 has a parallel surface 18g parallel to the light exit surface 18a between the inclined surface 18d and the base end surface 18i on the other surface. That is, in the thick portion 18b of the light guide plate 18, a parallel surface 18g extending from the inclined surface 18d is provided. Such a parallel surface 18g is not necessarily provided, but is preferably provided because it can improve the light use efficiency.
[0026] 導光板 18は、例えば、加熱した原料榭脂を押し出し成形や射出成形によって成形 する方法、型中でモノマー、オリゴマー等を重合させて成形する注型重合法等を用 いて製造することができる。導光板 18の材料としては、例えば、 PET (ポリエチレンテ レフタレート）、 PP (ポリプロピレン）、 PC (ポリカーボネート）、 PMMA (ポリメチノレメタ タリレート）、ベンジルメタタリレートや MS榭脂、その他のアクリル系榭脂、あるいは C OP (シクロォレフィンポリマー）などの透明榭脂を用いることができる。透明樹脂には 、光を散乱させるための微粒子を混入させても良ぐこれにより光射出面 18aからの 光の出射効率を一層高めることができる。  [0026] The light guide plate 18 is manufactured using, for example, a method in which heated raw material resin is molded by extrusion molding or injection molding, a casting polymerization method in which monomers, oligomers, and the like are molded in a mold. Can do. Examples of the material of the light guide plate 18 include PET (polyethylene terephthalate), PP (polypropylene), PC (polycarbonate), PMMA (polymethylol methacrylate), benzyl methacrylate and MS resin, and other acrylic resins. Transparent resin such as C OP (cycloolefin polymer) can be used. The transparent resin may be mixed with fine particles for scattering light, whereby the light emission efficiency from the light emission surface 18a can be further increased.
[0027] 導光板 18の厚肉部 18bの光射出面 18aと反対側には、光源 12を収容するための 平行溝 18fが長手方向に延在して形成される。平行溝 18fの深さは、光源 12の一部 が導光板 18の下面からはみ出さないように決定されることが好ましぐ光源 12の寸法 や導光板 18の機械的強度、経時変化を考慮して決定することが好ましい。また導光 板 18の肉厚部 18bや薄肉端部 18cの厚みは、光源 12の寸法に応じて任意に変更 することができる。ここで、導光板 18の平行溝 18fは、導光板 18の長手方向に対して 垂直な方向に形成してもよいが、平行溝 18fに収容される光源 12からの光利用効率 を高めるためには長手方向に形成することが好ましい。  [0027] On the opposite side of the light emitting surface 18a of the thick portion 18b of the light guide plate 18, a parallel groove 18f for accommodating the light source 12 is formed extending in the longitudinal direction. The depth of the parallel groove 18f is determined so that a part of the light source 12 does not protrude from the lower surface of the light guide plate 18. Is preferably determined. The thickness of the thick portion 18b and the thin end portion 18c of the light guide plate 18 can be arbitrarily changed according to the dimensions of the light source 12. Here, the parallel groove 18f of the light guide plate 18 may be formed in a direction perpendicular to the longitudinal direction of the light guide plate 18, but in order to increase the light use efficiency from the light source 12 accommodated in the parallel groove 18f. Is preferably formed in the longitudinal direction.
平行溝 18fは、その先端部分を構成する 1対の先端面 18h及び基端部分を構成す る 1対の基端面 18iで形成され、光射出面 18aに対する、先端面 18hの傾斜より、基 端面 18iの傾斜の方が急峻である。すなわち、先端面 18hの接平面が光射出面 18a となす角度の最大値、つまり、最大傾斜角 Φπιより、基端面 18iの接平面が光射出面 18aとなす角度 (傾斜角） Φηの方が大きい。 The parallel groove 18f constitutes a pair of distal end surfaces 18h and a proximal end portion constituting the distal end portion thereof. The base end surface 18i is steeper than the front end surface 18h relative to the light exit surface 18a. That is, the maximum angle formed by the tangent plane of the tip end surface 18h and the light exit surface 18a, that is, the angle (inclination angle) Φη formed by the tangential plane of the base end surface 18i and the light exit surface 18a is greater than the maximum tilt angle Φπι. large.
[0028] その平行溝 18fに配置された光源 12から放射される光のうち、平行溝 18fを形成す る側面力も導光板 18の内部に入射した光は、導光板 18の傾斜面 18dで反射した後 、光射出面 18aから出射する。この時、導光板 18の下面力 一部の光が漏洩するが 、その漏洩した光は、導光板 18の傾斜面 18d側に形成された反射シート 22により反 射して、再び導光板 18の内部に入射して光射出面 18aから出射する。こうして、導光 板 18の光射出面 18aから均一な光が放射される。  [0028] Of the light emitted from the light source 12 arranged in the parallel groove 18f, the side force that forms the parallel groove 18f also enters the light guide plate 18 and is reflected by the inclined surface 18d of the light guide plate 18. After that, the light exits from the light exit surface 18a. At this time, a part of light on the lower surface of the light guide plate 18 leaks, but the leaked light is reflected by the reflection sheet 22 formed on the inclined surface 18d side of the light guide plate 18 and again of the light guide plate 18. It enters the interior and exits from the light exit surface 18a. Thus, uniform light is emitted from the light exit surface 18a of the light guide plate 18.
なお、光射出面 18aから射出される光を均一化するために、光射出面 18aに対し直 角、平行方向（奥行き方向）に光束が有効に届くように傾斜面 18dの角度 (テーパ）を 制限することが好ましい。すなわち、傾斜面 18dの角度 (テーパ）を、光源 12から射出 され、導光板 18に入射した光束の一部が光射出面 18a (裏面)で全反射するような 角度にすることが好ましい。  In order to make the light emitted from the light exit surface 18a uniform, the angle (taper) of the inclined surface 18d is set so that the light beam effectively reaches the light exit surface 18a at a right angle and in a parallel direction (depth direction). It is preferable to limit. In other words, it is preferable that the angle (taper) of the inclined surface 18d is such that a part of the light beam emitted from the light source 12 and incident on the light guide plate 18 is totally reflected by the light emitting surface 18a (back surface).
[0029] 導光板 18の平行溝 18fは、平行溝 18fの長さ方向に垂直な断面形状において、そ の先端部分が三角形をなし、その基端部分が矩形をなし、全体として、光射出面 18a 側に凸のホームベース形状となるように形成される。従って、平行溝 18fの 1対の先 端面 18hは、それぞれの一方の端部が互いに交わり、光射出面 18aに対して垂直か つ光源の中心を通過する垂直面に対して、所定角度で傾斜して対称であり、その断 面形状は、三角形の 1つの頂点をなす所定角度の傾斜を有する 2つの線分 (斜辺） で形成される。導光板 18の平行溝 18fの 1対の基端面 18iは、それぞれの一方の端 部が 1対の先端面 18hのそれぞれの他方の端部に繋がり、上記垂直面に対して平行 かつ対称であり、その断面形状は、三角形の残りの 2つの頂点にそれぞれ接し、それ ぞれ導光板 18の平行面 18gに繋がる光射出面 18aに対して垂直な線分で形成され る。  [0029] The parallel groove 18f of the light guide plate 18 has a cross-sectional shape perpendicular to the length direction of the parallel groove 18f, the tip portion of which forms a triangle, and the base end portion of which forms a rectangle. It is formed to have a convex home base shape on the 18a side. Therefore, the pair of leading end surfaces 18h of the parallel grooves 18f are inclined at a predetermined angle with respect to the vertical plane passing through the center of the light source perpendicular to the light emitting surface 18a, with one end of each of them intersecting each other. The cross-sectional shape is formed by two line segments (slopes) having a predetermined angle of inclination forming one vertex of the triangle. A pair of base end surfaces 18i of the parallel grooves 18f of the light guide plate 18 are connected to the other ends of the pair of front end surfaces 18h, and are parallel and symmetrical with respect to the vertical surface. The cross-sectional shape is formed by line segments that are in contact with the remaining two vertices of the triangle and are perpendicular to the light exit surface 18a connected to the parallel surface 18g of the light guide plate 18, respectively.
[0030] 反射シート 22は、導光板 18の傾斜面 18dから漏洩する光を反射して、再び導光板 18に入射させるものであり、光の利用効率を向上させることができる。反射シート 22 は、導光板 18の傾斜面 18dを覆うように形成される。 [0030] The reflection sheet 22 reflects the light leaking from the inclined surface 18d of the light guide plate 18 and makes it incident on the light guide plate 18 again, thereby improving the light use efficiency. Reflective sheet 22 Is formed so as to cover the inclined surface 18d of the light guide plate 18.
反射シート 22は、導光板 18の傾斜面 18dから漏洩する光を反射することができるも のであれば、どのような材料で形成されてもよぐ例えば、 PETや PP (ポリプロピレン） 等にフィラーを混練後延伸することによりボイドを形成して反射率を高めた榭脂シート 、透明もしくは上記のような白色の榭脂シート表面にアルミ蒸着などで鏡面を形成し たシート、アルミ等の金属箔もしくは金属箔を担持した榭脂シート、あるいは表面に十 分な反射性を有する金属薄板により形成することができる。  The reflection sheet 22 may be formed of any material as long as it can reflect light leaking from the inclined surface 18d of the light guide plate 18. For example, a filler is applied to PET, PP (polypropylene), or the like. A resin sheet with increased reflectivity by forming voids by stretching after kneading, a sheet with a mirror surface formed by aluminum deposition or the like on the surface of a transparent or white resin sheet as described above, or a metal foil such as aluminum or the like It can be formed of a resin sheet carrying a metal foil, or a thin metal plate having sufficient reflectivity on the surface.
[0031] リフレクタ 20は、導光板 18の平行溝 18fを塞ぐように光源 12の下面に設けられる。  [0031] The reflector 20 is provided on the lower surface of the light source 12 so as to close the parallel grooves 18f of the light guide plate 18.
リフレクタ 20は、光源 12の下面で光を反射して、導光板 18の平行溝 18fを形成する 側壁力 光を導光板 18へ入射させることができる。  The reflector 20 reflects the light on the lower surface of the light source 12 to allow the side wall force light that forms the parallel grooves 18 f of the light guide plate 18 to enter the light guide plate 18.
リフレクタ 20は、例えば、上記反射シートと同じ素材、すなわち、表面に十分な反射 性を付与した榭脂素材、金属箔もしくは金属板により形成することができる。  The reflector 20 can be formed of, for example, the same material as that of the reflection sheet, that is, a resin material, a metal foil, or a metal plate that gives the surface sufficient reflectivity.
[0032] 透過率調整部材 28は、導光板 18から出射される光の輝度むらを低減させるもので あり、光透過性を有する光学部材である透明フィルム 29と、透明フィルム 29の表面で あって導光板 18と対向する面上に、所定の密度分布をもって配置される複数の透過 率調整体 26とを有する。  [0032] The transmittance adjusting member 28 reduces unevenness in luminance of light emitted from the light guide plate 18, and is a transparent film 29 that is an optical member having light transmittance, and the surface of the transparent film 29. A plurality of transmittance adjusting bodies 26 are disposed on the surface facing the light guide plate 18 with a predetermined density distribution.
[0033] 透明フィルム 29は、フィルム状の形状であって光透過性を有し、導光板 18と拡散フ イルム 14の間に配置される。透明フィルム 29は、 PET (ポリエチレンテレフタレート）、 PP (ポリプロピレン）、 PC (ポリカーボネート）、 PMMA (ポリメチノレメタタリレート）、ベ ンジルメタタリレートや MS榭脂、その他のアクリル系榭脂、あるいは COP (シクロォレ フィンポリマー）等の光学的に透明な部材で形成される。  The transparent film 29 has a film-like shape and is light transmissive, and is disposed between the light guide plate 18 and the diffusion film 14. Transparent film 29 is made of PET (polyethylene terephthalate), PP (polypropylene), PC (polycarbonate), PMMA (polymethylol methacrylate), benzyl methacrylate, MS resin, other acrylic resins, or COP. It is formed of an optically transparent member such as (cycloolefin polymer).
[0034] 透過率調整体 26は、所定の透過率を有し、複数の透過率調整体 26が下記式（1) に示す所定の密度分布 /0 (X, y)をもって透明フィルムの表面上に配置されることが 好ましい。  [0034] The transmittance adjusting body 26 has a predetermined transmittance, and the plurality of transmittance adjusting bodies 26 have a predetermined density distribution / 0 (X, y) represented by the following formula (1) on the surface of the transparent film. It is preferable to be arranged in
p (x, y) =c{F (x, y) -F }/ (F F ) 式（1)  p (x, y) = c {F (x, y) -F} / (F F) Equation (1)
min max min  min max min
(c :透過率調整体を配置する全領域における最大密度、 F (x, y)：透過率調整体を 含まない状態における任意の領域 (X, y)での光射出面の輝度分布、 F ：光射出面  (c: Maximum density in the entire region where the transmittance adjusting body is arranged, F (x, y): Luminance distribution on the light exit surface in any region (X, y) without the transmittance adjusting body, F : Light exit surface
max  max
力ゝら出射される光の最大輝度 (透過率調整体を含まない状態における光射出面から 出射される光の最大輝度）、 F ：光射出面から出射される光の最小輝度 (透過率調 The maximum luminance of the light emitted from the force (from the light exit surface in the state that does not include the transmittance adjuster) Maximum brightness of emitted light), F: Minimum brightness of light emitted from the light exit surface (transmittance adjustment)
min  min
整体を含まない状態における光射出面力 出射される光の最小輝度)）  Light exiting surface force without manipulative force Minimum brightness of emitted light))
この密度分布は、輝度むらを抑えるために配置する透過率調整体 26の好まし 、配 置パターンの一例であり、本発明者によって見出されたものである。  This density distribution is a preferred example of the arrangement pattern of the transmittance adjusting body 26 arranged to suppress luminance unevenness, and is an example of an arrangement pattern, and was found by the present inventor.
[0035] 複数の透過率調整体 26が所定の密度分布をもって配置されることにより、導光板 1[0035] By arranging a plurality of transmittance adjusting bodies 26 with a predetermined density distribution, the light guide plate 1
8の光射出面 18aから出射される光の輝度むらを低減させることができる。 The brightness unevenness of the light emitted from the eight light exit surfaces 18a can be reduced.
透過率調整体 26は、透明フィルム 29の導光板 18側の表面にオフセット印刷、ダラ ビア凹版印刷、スクリーン印刷またはインクジェット印刷等によって形成することがで きる。  The transmittance adjusting body 26 can be formed on the surface of the transparent film 29 on the light guide plate 18 side by offset printing, Darvia intaglio printing, screen printing, ink jet printing, or the like.
オフセット印刷は生産性に優れており、グラビア凹版印刷は、生産性に優れるととも に、インクの厚みを変えることができるので濃度階調の豊富な高品質の印刷が可能と なる。また、スクリーン印刷は、透過率調整体として塗工するインクの厚さを厚くするこ とができ、インク濃度を高くしなくても、透過率調整体の透過率を低くすることができる 。また、インクジェット印刷は、立体物に直接印刷することができるので、導光板など に直接印刷する際にこの方法を用いることが好ましい。これら透過率調整体の形成 方法はその目的に応じて適宜使い分けることが好ましい。  Offset printing is excellent in productivity, and gravure intaglio printing is excellent in productivity, and the thickness of ink can be changed, so that high-quality printing with rich density gradation is possible. Further, screen printing can increase the thickness of ink applied as a transmittance adjusting body, and can reduce the transmittance of the transmittance adjusting body without increasing the ink concentration. Moreover, since inkjet printing can print directly on a three-dimensional object, it is preferable to use this method when printing directly on a light guide plate or the like. These methods for forming the transmittance adjusting body are preferably properly used depending on the purpose.
[0036] また、複数の透過率調整体 26は、その寸法 (以下「ドットサイズ」ともいう。 )の最大 のもの（以下「透過率調整体の最大寸法」 t 、う。）が 500 μ m以下の微小なドットから なる。ドットの形状は、矩形、三角形、六角形、円形、楕円形等でもよぐ特に限定は ない。 [0036] In addition, the plurality of transmittance adjusting bodies 26 have the largest dimension (hereinafter also referred to as "dot size") (hereinafter "maximum dimension of transmittance adjusting body" t). It consists of the following small dots. The shape of the dot is not particularly limited, and may be a rectangle, triangle, hexagon, circle, ellipse, or the like.
透過率調整体の最大寸法を 500 m以下にすることで、光源や導光板などと組み 合わせてバックライトユニット 2を構成したときに、ノ ックライトユニット 2の光射出面から 透過率調整体が目視されにくくなる。ノ ックライトユニット 2の光射出面力も透過率調 整体が目視される場合には、透過率調整体によって光源の均質さが妨げられる。そ のため、透過率調整体を目視されに《することにより均質な光源を得ることができる 。なお、透過率調整体の最小寸法 (寸法の最小のもの）は、製造技術や製造コストを 考慮すると 20 mである。  By setting the maximum size of the transmittance adjustment body to 500 m or less, when the backlight unit 2 is configured in combination with a light source, a light guide plate, etc., the transmittance adjustment body can be seen from the light exit surface of the knock light unit 2. It becomes difficult to see. When the transmittance adjusting body of the light emission surface force of the knock light unit 2 is visually observed, the transmittance adjusting body prevents the homogeneity of the light source. Therefore, a uniform light source can be obtained by making the transmittance adjusting body visible. The minimum dimension of the transmittance adjuster (the smallest dimension) is 20 m in consideration of manufacturing technology and manufacturing cost.
また、透過率調整体の最大寸法は 200 m以下とすることがより好ましい。透過率 調整体の最大寸法をこの大きさで設計すると、バックライトユニット 2の光射出面から 透過率調整体が目視されな ヽためである。 The maximum dimension of the transmittance adjusting body is more preferably 200 m or less. Transmittance This is because if the maximum dimension of the adjusting body is designed with this size, the transmittance adjusting body will not be seen from the light exit surface of the backlight unit 2.
[0037] 透過率調整体 26としては、拡散反射体を用いることができる。拡散反射体は、例え ば、光を散乱させるシリカ、酸化チタン、酸化亜鉛等の顔料、あるいは榭脂、ガラス、 ジルコユア等のビーズ類を、バインダとともに塗工した物である。 [0037] As the transmittance adjusting body 26, a diffuse reflector can be used. For example, the diffuse reflector is a product obtained by coating pigments such as silica, titanium oxide, and zinc oxide that scatter light, or beads such as rosin, glass, and zirconium oxide together with a binder.
他には、反射率が高く光の吸収が低い材料で、例えば、 Ag、 A1のような金属を用 いることちでさる。  Others are materials with high reflectivity and low light absorption, such as the use of metals such as Ag and A1.
[0038] 拡散フィルム 14は、導光板 18の光射出面 18aから出射する光を拡散して均一化す るためのものである。ここで、拡散フィルム 14は、透過率調整体との関係を考慮して、 その光学特性を設定することにより、輝度分布のむらを改善することができ、導光板 の光射出面から出射した光をより均一な出射光にすることができる。  [0038] The diffusion film 14 is for diffusing and uniformizing light emitted from the light exit surface 18a of the light guide plate 18. Here, the diffusion film 14 can improve the unevenness of the luminance distribution by setting the optical characteristics in consideration of the relationship with the transmittance adjusting body, and can emit the light emitted from the light exit surface of the light guide plate. More uniform outgoing light can be obtained.
具体的には、拡散フィルム 14について設定する光学特性は、ヘイズ値、視野角及 び全光線透過率であり、透過率調整体 26のドットサイズは 500 m以下に設定する 。ここで、拡散フィルムの光学特性は、視野半値角ならば 2. 5° 以上、全光線透過率 ならば 90%以下、またはヘイズならば 85%以上に設定する。あるいは、これら光学 特性の 2つ以上を組み合わせてもよい。例えば、ヘイズ値を 85%以上、かつ視野半 値角を 2. 5° 以上と設定してもよい。  Specifically, the optical characteristics set for the diffusion film 14 are haze value, viewing angle and total light transmittance, and the dot size of the transmittance adjusting body 26 is set to 500 m or less. Here, the optical properties of the diffusing film are set to 2.5 ° or more for the half angle of view, 90% or less for the total light transmittance, or 85% or more for the haze. Alternatively, two or more of these optical characteristics may be combined. For example, the haze value may be set to 85% or more and the viewing half-value angle may be set to 2.5 ° or more.
このように、透過率調整体 26のドットサイズを目視されにくい程度に小さくし、さらに 、拡散フィルムの光学特性を上記範囲とすることによって、平均輝度低下を防止しつ つ (輝度を維持した状態で)、透過率調整体 26が視認されることも防止された均一な 光源を得ることができる。  In this way, by reducing the dot size of the transmittance adjusting body 26 to such an extent that it is difficult to see, and by setting the optical characteristics of the diffusion film within the above range, it is possible to prevent a decrease in average luminance (in a state where the luminance is maintained). Therefore, it is possible to obtain a uniform light source that prevents the transmittance adjusting body 26 from being visually recognized.
なお、これらの光学特性の数値範囲は、本発明者によって見出されたものであり、 以下に示す実施例 1の結果に基づくものである。  The numerical ranges of these optical properties were found by the present inventors and are based on the results of Example 1 shown below.
ここで、視野半値角とは、一般に光出射平面中心の法線を突き抜ける光を 0° の光 と定義し、その強度が半値になる角度を示す。  Here, the half-value angle of the field of view generally indicates an angle at which the intensity of the light that penetrates the normal line at the center of the light emission plane is defined as 0 ° light and the intensity becomes half value.
[0039] 拡散フィルム 14は、例えば、 PET (ポリエチレンテレフタレート）、 PP (ポリプロピレン )、 PC (ポリカーボネート）、 PMMA (ポリメチルメタタリレート）、ベンジルメタタリレート や MS榭脂、その他のアクリル系榭脂、あるいは COP (シクロォレフィンポリマー）のよ うな光学的に透明な榭脂からなるフィルム状部材に光拡散性を付与して形成される。 その製造方法は特に限定されないが、例えば、上記平板状部材の表面に微細凹 凸加工や研磨による表面粗化 (以降これらを施した面を「砂擦り面」という。）を施して 拡散性を付与したり、表面に光を散乱させるシリカ、酸化チタン、酸化亜鉛等の顔料 、もしくは榭脂、ガラス、ジルコユア等のビーズ類をバインダとともに塗工したり、光を 散乱させる前述の顔料、ビーズ類を上記の榭脂中に混練することで形成することが できる。 [0039] The diffusion film 14 is made of, for example, PET (polyethylene terephthalate), PP (polypropylene), PC (polycarbonate), PMMA (polymethyl methacrylate), benzyl methacrylate, MS resin, and other acrylic resins. Or COP (cycloolefin polymer) It is formed by imparting light diffusibility to a film-like member made of such an optically transparent resin. The manufacturing method is not particularly limited. For example, the surface of the flat plate member is subjected to surface roughening by fine uneven processing or polishing (hereinafter, the surface on which these are applied is referred to as “sand-rubbed surface”) to improve the diffusibility. Apply the pigments such as silica, titanium oxide, and zinc oxide that scatter light to the surface, or beads such as resin, glass, and zirconium oxide together with the binder, and the aforementioned pigments and beads that scatter light Can be formed by kneading into the above-mentioned rosin.
他には、反射率が高く光の吸収が低い材料で、例えば、 Ag、 A1のような金属を用 いて形成することもできる。  In addition, it is possible to use a material having high reflectivity and low light absorption, for example, a metal such as Ag or A1.
[0040] 本発明において、拡散フィルム 14としては、マットタイプやコーティングタイプの拡 散フィルムを用いることができる。 In the present invention, the diffusion film 14 may be a mat type or coating type diffusion film.
本発明において、拡散フィルム 14としては、上記の素材を用い、かつ、光拡散性を 付与した厚み 500 μ m以下のフィルム状部材を用いることが好ましい。  In the present invention, as the diffusing film 14, it is preferable to use a film-like member having a thickness of 500 μm or less, using the above-mentioned material and imparting light diffusibility.
[0041] 拡散フィルム 14は、導光板 18の光射出面 18aから所定の距離だけ離して配置され てもよぐその距離は導光板 18の光射出面 18aからの光量分布に応じて適宜変更し 得る。 [0041] The diffusion film 14 may be arranged at a predetermined distance from the light exit surface 18a of the light guide plate 18. The distance may be appropriately changed according to the light amount distribution from the light exit surface 18a of the light guide plate 18. obtain.
このように拡散フィルム 14を導光板 18の光射出面 18aから所定の間隔だけ離すこ とにより、導光板 18の光射出面 18aから射出する光が、光射出面 18aと拡散フィルム 14の間で更にミキシング (混合）される。これにより、拡散フィルム 14を透過して液晶 表示パネル 4を照明する光の輝度を、より一層均一化することができる。  Thus, by separating the diffusion film 14 from the light exit surface 18a of the light guide plate 18 by a predetermined distance, the light emitted from the light exit surface 18a of the light guide plate 18 is transferred between the light exit surface 18a and the diffusion film 14. It is further mixed (mixed). As a result, the luminance of the light that passes through the diffusion film 14 and illuminates the liquid crystal display panel 4 can be made more uniform.
拡散フィルム 14を導光板 18の光射出面 18aから所定の間隔だけ離す方法としては 、例えば、拡散フィルム 14と導光板 18との間にスぺーサを設ける方法を用いることが できる。  As a method of separating the diffusion film 14 from the light exit surface 18a of the light guide plate 18 by a predetermined distance, for example, a method of providing a spacer between the diffusion film 14 and the light guide plate 18 can be used.
[0042] 特に、ノ ックライトユニット 2の厚みを少し厚くしてもよい場合には、導光板 18の平行 溝 18fの断面形状によって、平行溝 18fに相当する導光板 18の光射出面 18aにおけ る輝度のピーク値を十分に低減する必要はなぐ部分的に低減するとともに拡散フィ ルム 14と導光板 18の光射出面 18aとの間に間隙を設けて、拡散フィルム 14力も射 出される照明光の輝度分布を均一にしても良い。 [0043] プリズムシート 16及び 17は、複数のプリズムを平行に配列させることにより形成され た透明なシートであり、導光板 18の光射出面 18aから出射する光の集光性を高めて 輝度を改善することができる。 [0042] In particular, when the thickness of the knock light unit 2 may be slightly increased, the light emitting surface 18a of the light guide plate 18 corresponding to the parallel groove 18f is formed depending on the cross-sectional shape of the parallel groove 18f of the light guide plate 18. It is necessary to reduce the peak value of the brightness sufficiently, and a gap is provided between the diffusion film 14 and the light exit surface 18a of the light guide plate 18 to illuminate the diffusion film 14 force. The luminance distribution of light may be made uniform. [0043] The prism sheets 16 and 17 are transparent sheets formed by arranging a plurality of prisms in parallel. The prism sheets 16 and 17 increase the light collecting property of the light emitted from the light exit surface 18a of the light guide plate 18 to increase the luminance. Can be improved.
プリズムシート 16及び 17の一方は、そのプリズム列の延在する方向が導光板 18の 平行溝 18fと平行になるように配置され、他方は垂直になるように配置される。すなわ ち、プリズムシート 16及び 17は、プリズム列の延在する方向が互いに垂直になるよう に配置される。  One of the prism sheets 16 and 17 is disposed so that the extending direction of the prism row is parallel to the parallel groove 18f of the light guide plate 18, and the other is disposed vertically. That is, the prism sheets 16 and 17 are arranged so that the extending directions of the prism rows are perpendicular to each other.
また、プリズムシート 16及び 17は、プリズムの頂角が導光板 18の光射出面 18aと反 対側を向くように配置される。  The prism sheets 16 and 17 are arranged so that the apex angle of the prism faces the light exit surface 18 a of the light guide plate 18.
[0044] なお、ここでは、プリズムシート 16及び 17の配置順序は、導光板の直上に、導光板 の平行溝と平行な方向に延在するプリズムを有するプリズムシート 16を配置し、その プリズムシート 16の上に、導光板 18の平行溝 18fと垂直な方向に延在するプリズムを 有するプリズムシート 17を配置しても良ぐまた、その逆でも良い。また、プリズムシー トは、必ずしも 2枚用いる必要はなぐ 1枚であってもよい。 Here, the prism sheets 16 and 17 are arranged in the order in which the prism sheet 16 having a prism extending in a direction parallel to the parallel groove of the light guide plate is disposed immediately above the light guide plate. A prism sheet 17 having prisms extending in a direction perpendicular to the parallel grooves 18f of the light guide plate 18 may be disposed on the 16 or vice versa. Further, it is not always necessary to use two prism sheets.
また、図示例ではプリズムシート 16及び 17を用いた力 プリズムシートの代わりに、 プリズムに類する光学部材が規則的に配置されたシートを用いても良い。また、レン ズ効果を有する素子、例えば、レンチキュラーレンズ、凹レンズ、凸レンズ、ピラミッド 型などの光学部材を規則的に備えるシートをプリズムシートの代わりに用いることもで きる。  In the illustrated example, instead of the force prism sheet using the prism sheets 16 and 17, a sheet in which optical members similar to prisms are regularly arranged may be used. Further, an element having a lens effect, for example, a sheet regularly provided with optical members such as a lenticular lens, a concave lens, a convex lens, and a pyramid type can be used instead of the prism sheet.
[0045] 以上のように、透過率調整部材及び拡散フィルムからなる本発明の光学部材及び 本発明のバックライトユニット (面状照明装置）によれば、透過率調整体の最大寸法と 拡散フィルムの光学特性にっ ヽて規定し、拡散フィルムと透過率調整体との関係を 考慮することにより、輝度分布のむらを改善することができ、均質な光源を得ることが できる。つまり、透過率調整体が視認されることを防止し、かつ輝度むらを低減するこ とができる。すなわち、透過率調整体が視認されることを防止でき、輝度分布のむら をより低減させることができる。さらに、輝度が低減することも防止できる。  [0045] As described above, according to the optical member of the present invention comprising the transmittance adjusting member and the diffusion film and the backlight unit (planar illumination device) of the present invention, the maximum size of the transmittance adjusting body and the diffusion film By defining the optical characteristics and considering the relationship between the diffusion film and the transmittance adjusting body, the unevenness of the luminance distribution can be improved, and a homogeneous light source can be obtained. That is, it is possible to prevent the transmittance adjusting body from being visually recognized and to reduce luminance unevenness. That is, the transmittance adjusting body can be prevented from being visually recognized, and the unevenness of the luminance distribution can be further reduced. Furthermore, it is possible to prevent the luminance from being reduced.
また、本発明の面状照明装置と液晶表示パネルとを組み合わせて液晶表示装置を 作製した場合に、良好な画質の液晶表示装置を提供することができる。 実施例 1 In addition, when a liquid crystal display device is manufactured by combining the planar lighting device of the present invention and a liquid crystal display panel, a liquid crystal display device with good image quality can be provided. Example 1
[0046] 以下、具体的実施例とともに、本発明の光学部材及びそれを用いる面状照明装置 についてより詳細に説明する。  [0046] Hereinafter, the optical member of the present invention and the planar lighting device using the same will be described in more detail with specific examples.
[0047] 図 2は、本実施例に用いたバックライトユニットの概略構成を示す断面図である。 FIG. 2 is a cross-sectional view showing a schematic configuration of the backlight unit used in this example.
ノ ックライトユニット 30は、光源 12と、導光板 38と、拡散フィルム 14と、プリズムシー ト 16と、リフレクタ 20と、反射シート 22と、透過率調整体ユニット 28とを有して構成さ れる。  The knock light unit 30 includes a light source 12, a light guide plate 38, a diffusion film 14, a prism sheet 16, a reflector 20, a reflection sheet 22, and a transmittance adjusting body unit 28. .
ここでは、光源 12には、直径 Rが 2mmの冷陰極管を使用した。導光板 38は、図 2 に示す形状の導光板 38であって以下に示す寸法に従ったものを使用した。  Here, a cold cathode tube having a diameter R of 2 mm was used as the light source 12. As the light guide plate 38, a light guide plate 38 having the shape shown in FIG. 2 and having the following dimensions was used.
導光板 38の中央 (平行溝 38fの中央)から導光板 38の一方の端面までの距離 Lは 15mmであり、導光板 38の中央部近辺の肉厚部 38bの厚みは最も厚い部分 dOで 4 . 5mmであり、平行溝 38fの先端部分 (平行溝 38fの中央)と光出射面との距離 dlは lmmであり、導光板 38の端面の厚み d2は 1. 5mmであり、平行溝 38fの幅は最も広 Vヽ部分 G1で 4mmである導光板 38を使用した。  The distance L from the center of the light guide plate 38 (the center of the parallel groove 38f) to one end face of the light guide plate 38 is 15 mm, and the thick part 38b near the center of the light guide plate 38 has the thickest part dO 4 The distance between the tip of the parallel groove 38f (the center of the parallel groove 38f) and the light exit surface is dl, and the thickness d2 of the end face of the light guide plate 38 is 1.5mm. The light guide plate 38, which has the widest V ヽ part G1 and a width of 4 mm, was used.
[0048] まず、視認性の評価を定量的に行うために以下の方法により視認限界値を決定し た。ここで、視認限界値とは、ノ ックライトユニットの光出射面より 30cm離れた位置か ら透過率調整体を観察した場合において、官能評価によって実質的に透過率調整 体を目視できなくなる明度変化率 dB/dxを意味する。  [0048] First, in order to quantitatively evaluate the visibility, the visibility limit value was determined by the following method. Here, the visibility limit value is the change in brightness that makes it impossible to visually see the transmittance adjustment body by sensory evaluation when the transmittance adjustment body is observed from a position 30 cm away from the light exit surface of the knocklight unit. The rate means dB / dx.
[0049] 種々の条件の透過率調整部材 28と拡散フィルム 14を積層してなる光学部材を用 Vヽたバックライトユニット 30を作製し、作製したバックライトユニット 30のそれぞれにつ いて、下記方法で官能評価を行なった。  [0049] A backlight unit 30 using an optical member formed by laminating the transmittance adjusting member 28 and the diffusion film 14 under various conditions was manufactured, and the following method was performed for each of the manufactured backlight units 30. The sensory evaluation was performed.
官能評価は、 20人の被験者が、ノ ックライトユニット 30の光出射面より 30cm離れ た位置カゝら透過率調整体を観察して行なった。被験者が観察した結果、 20人全員 が透過率調整体を目視できな!/ヽと評価した場合を透過率調整体が視認されな ヽ場 合とし、 20人のうち 1人でも透過率調整体を目視することができたと評価した場合を 透過率調整体が視認される場合とした。  The sensory evaluation was performed by observing the transmittance adjusting body at a position 30 cm away from the light emitting surface of the knocklight unit 30 by 20 subjects. As a result of the observation by the test subjects, when all 20 people could not see the transmittance adjustment body! / ヽ, the transmittance adjustment body was not visible, and even one of the 20 people had the transmittance adjustment body. The case where the transmittance adjusting body was visually recognized was evaluated as the case where it was evaluated that
[0050] 次に、この透過率調整体が視認される場合と透過率調整体が視認されな!/ヽ場合の それぞれの場合につ 、て、明度 Bとその変化率 dBZdxを測定した。 具体的には、デジタルカメラ（富士写真フィルム製 Fine Pix S2Pro)に 85mm レンズ (ニコン社製)を装着し、 70cmの距離からバックライトユニットの出射面を撮影 し、 8ビット画像データを取得した。 [0050] Next, the brightness B and the rate of change dBZdx were measured for each of the cases where the transmittance adjusting body was visually recognized and when the transmittance adjusting body was not visually recognized! Specifically, an 85mm lens (Nikon Corporation) was attached to a digital camera (Fuji Photo Film Fine Pix S2Pro), and the exit surface of the backlight unit was photographed from a distance of 70 cm to obtain 8-bit image data.
ノックライトユニットを撮影した画像データを基に、 RGB成分の明度を測定し、さら に測定した明度に基づいて、明度変化率 dB/dxを算出した。明度変化率 dB/dxは、 1ρίχΘΐ(40 ^ πι)当たりの明度 Βの変化量をビット数の変化量の絶対値で示したもの である。  Based on the image data of the knocklight unit, the brightness of the RGB component was measured, and the brightness change rate dB / dx was calculated based on the measured brightness. The lightness change rate dB / dx is the absolute value of the change in lightness 当 た り per 1ρίχΘΐ (40 ^ πι).
[0051] 図 3Αに、透過率調整体が視認される場合のバックライトユニットの光出射面を撮影 した画像データを基に測定した RGB成分の明度 Βの測定結果の一例を示し、図 3B に、図 3Aに示した各成分の明度 Bに基づいて算出した明度変化率 dB/dxを示す。 また、図 4Aに、それぞれ透過率調整体が視認されない場合のバックライトユニットの 光出射面を撮影した画像データを基に測定した RGB成分の明度 Bの測定結果の一 例を示し、図 4Bに、図 4Aに示した各成分の明度 Bに基づいて算出した明度変化率 dB/dxを示す。  [0051] Fig. 3B shows an example of the measurement result of the brightness Β of the RGB component measured based on the image data obtained by photographing the light exit surface of the backlight unit when the transmittance adjusting body is visually recognized. The brightness change rate dB / dx calculated based on the brightness B of each component shown in FIG. 3A is shown. In addition, Fig. 4A shows an example of the measurement result of brightness B of the RGB component measured based on the image data obtained by photographing the light exit surface of the backlight unit when the transmittance adjusting body is not visually recognized, and Fig. 4B. The brightness change rate dB / dx calculated based on the brightness B of each component shown in FIG. 4A is shown.
図 3A及び図 4Aは、縦軸に明度を 256段階のビット数で示し、横軸に測定位置を p ixel (l pixel =40 μ m)を単位として示す。  In FIG. 3A and FIG. 4A, the vertical axis shows the brightness in 256 steps and the horizontal axis shows the measurement position in pixels (l pixel = 40 μm).
一方、図 3B及び図 4Bは、縦軸に明度変化率 dB/dx[bitZpixel]を lpixel O /z m)当たりのビット数の変化量の絶対値で示し、横軸に測定位置を pixel (lpixel=4 O ^ m)を単位として示す。  On the other hand, in FIG. 3B and FIG. 4B, the vertical axis shows the rate of change in brightness dB / dx [bitZpixel] as the absolute value of the amount of change in the number of bits per lpixel O / zm), and the horizontal axis shows the measurement position in pixels (lpixel = 4 O ^ m) is shown as a unit.
また、図 3及び図 4の横軸位置 X [pixel]は、原点を、バックライトユニットの中央 (導 光板の平行溝の先端部分に相当する光射出面上の位置)から光源の軸方向に対し て垂直な方向に 271pixel(10840 m)離れた位置とした。つまり、横軸におていは 、 271pixelの位置がバックライトユニットの中央となる。  The horizontal axis position X [pixel] in FIGS. 3 and 4 is the origin in the axial direction of the light source from the center of the backlight unit (position on the light exit surface corresponding to the tip of the parallel groove of the light guide plate). The position was 271 pixels (10840 m) away in the vertical direction. In other words, on the horizontal axis, the position of 271 pixels is the center of the backlight unit.
[0052] 図 3B及び図 4Bに示す測定結果より算出した RGB成分それぞれの明度変化率の ピーク値の上位 10点の平均値と、官能評価の結果とから、明度変化率の視認限界 値、つまり、ノ ックライトユニットの光出射面より 30cm離れた位置力も透過率調整体 を観察した場合において、官能評価によって実質的に透過率調整体が目視できなく なる明度変化率 dBZdxは、 3. 0となることが分力つた。 [0053] 次に、透過率調整体の寸法 (ドットサイズ)の異なる透過率調整部材と、光学特性の 異なる拡散フィルムとを 200 μ mだけ離間して積層した光学部材を用いたバックライト ユニットを複数作製し、それぞれのバックライトユニットにつ 、て透過率調整体が視認 されるか否か (視認性)を評価した。 [0052] From the average value of the top 10 peak values of the brightness change rate of each RGB component calculated from the measurement results shown in FIGS. 3B and 4B, and the sensory evaluation result, the visibility limit value of the brightness change rate, that is, When the transmittance adjusting body is also observed at a position force 30 cm away from the light exit surface of the knocklight unit, the lightness change rate dBZdx is 3.0, which is substantially invisible by sensory evaluation. It became a force. [0053] Next, a backlight unit using an optical member in which a transmittance adjusting member having a different dimension (dot size) of the transmittance adjusting body and a diffusion film having different optical characteristics are laminated by being separated by 200 μm is provided. A plurality of them were produced, and whether or not the transmittance adjusting body was visually recognized (visibility) was evaluated for each backlight unit.
ここで、拡散フィルムの光学特性は、視野半値角、全光線透過率及びヘイズであり 、透明フィルムに塗設した散乱体の密度、粒子径、種類、拡散フィルム表裏の塗布量 等を変えることにより光学特性の異なる種々の拡散フィルムを作製した。  Here, the optical characteristics of the diffusion film are the half-value angle of view, the total light transmittance, and the haze. By changing the density, particle diameter, type, amount of coating on the front and back of the diffusion film, etc., applied to the transparent film. Various diffusion films having different optical properties were prepared.
[0054] 表 1に、拡散フィルムの視野半値角と透過率調整体のドットサイズを変化させた複 数のノ ックライトユニットについて、それぞれ測定し算出した明度変化率と視認性の 判定の結果とを、各バックライトユニットの拡散フィルムの視野半値角と透過率調整体 のドットサイズとともに示す。  [0054] Table 1 shows the brightness change rate and the visibility determination results obtained by measuring and calculating a plurality of knock light units in which the half-value angle of view of the diffusion film and the dot size of the transmittance adjusting body were changed. Is shown together with the half-value angle of view of the diffusion film of each backlight unit and the dot size of the transmittance adjuster.
[0055] ここで、視野半値角は、ゴ-オフオトメータ (村上色彩技術研究所製)を用いて、三 次元変角光度を、 BP— 200、 ND10、光源側及び受光側共に S偏光、 High Volt 600、受光絞り 6. 8mm φに設定し、測定した値である。  [0055] Here, the half-value angle of view was measured using a go-off otometer (Murakami Color Research Laboratory), the three-dimensional variable-angle luminous intensity, BP-200, ND10, S-polarized light on both the light source side and the light-receiving side, High Volt This is the value measured with 600 and aperture 6.8 mm φ.
[0056] また、視認性の判定は、透過率調整体が視認されないと判定した場合を「〇」で、 透過率調整体が視認されると判定した場合を「X」で示す。具体的には、デジタル力 メラで撮影して取得した明度変化率 dB/dxの値が 3. 0以下であれば目視されな ヽと 判定し、 3. 0より高ければ目視されると判定した。  [0056] Further, in the determination of visibility, a case where it is determined that the transmittance adjusting body is not visually recognized is indicated by "O", and a case where it is determined that the transmittance adjusting body is visually recognized is indicated by "X". Specifically, if the value of the rate of change in brightness dB / dx obtained by photographing with a digital power camera is 3.0 or less, it is determined that it is not visible, and if it is higher than 3.0, it is determined that it is visually observed. .
[0057] 表 2に、拡散フィルムの全光線透過率と透過率調整体のドットサイズを変化させた 複数のノ ックライトユニットについて、それぞれ測定し算出した明度変化率と視認性 の判定の結果とを、各バックライトユニットの全光線透過率と透過率調整体のドットサ ィズとともに示す。  [0057] Table 2 shows the results of the brightness change rate and the visibility determination results measured and calculated for each of the plurality of knock light units in which the total light transmittance of the diffusion film and the dot size of the transmittance adjuster were changed. Is shown together with the total light transmittance of each backlight unit and the dot size of the transmittance adjuster.
全光線透過率 [%]は、シングルビーム方式のヘイズメータ (スガ試験機社製 HZ— 1型）を用いて測定した値である。また、本実施例では、測定光として C光を用いて測 し 7こ。  The total light transmittance [%] is a value measured using a single beam type haze meter (HZ-1 type manufactured by Suga Test Instruments Co., Ltd.). In this example, the measurement light is 7 using C light.
また、視認性の判定は、表 1の場合と同様の方法で判定した。  Visibility was determined by the same method as in Table 1.
[0058] 表 3に、拡散フィルムのヘイズと透過率調整体のドットサイズを変化させた複数のバ ックライトユニットについて、それぞれ測定し算出した明度変化率と視認性の判定の 結果とを、各バックライトユニットのヘイズと透過率調整体のドットサイズとともに示す。 ヘイズ [%]は、シングルビーム方式のヘイズメータ (スガ試験機社製 HZ— 1型）を 用いて測定した値である。また、本実施例でも、測定光として C光を用いて測定した。 また、視認性の判定は、表 1の場合と同様の方法で判定した。 [0058] Table 3 shows the brightness change rate and the visibility judgment for each of the backlight units in which the haze of the diffusion film and the dot size of the transmittance adjuster were changed. The results are shown together with the haze of each backlight unit and the dot size of the transmittance adjuster. The haze [%] is a value measured using a single beam type haze meter (HZ-1 type, manufactured by Suga Test Instruments Co., Ltd.). Also in this example, measurement was performed using C light as measurement light. Visibility was determined by the same method as in Table 1.
[0059] さらに、表 4に、拡散フィルムのヘイズ及び視野半値角を変化させた複数のバックラ イトユニットについて、それぞれ測定し算出した明度変化率と、輝度 [cdZcm2]と視 認性の判定の結果とを、各バックライトユニットの拡散フィルムのヘイズと視野半値角 とともに示す。ここで、表 4に示した実施例の透過率調整体のドットサイズは、いずれ も 450 μ mとした。 [0059] Further, Table 4 shows the brightness change rate, brightness [cdZcm 2 ], and visibility determination for each of a plurality of backlight units in which the haze and viewing half-value angle of the diffusion film were changed. The results are shown together with the haze and viewing half-value angle of the diffusion film of each backlight unit. Here, the dot sizes of the transmittance adjusting bodies of the examples shown in Table 4 were all 450 μm.
また、拡散フィルムのヘイズ及び視野半値角は、上述と同様の方法で測定した値で あり、輝度は、輝度計 (トプコン社製 BM— 7)を用いて測定した値である。  In addition, the haze and viewing half-value angle of the diffusion film are values measured by the same method as described above, and the luminance is a value measured using a luminance meter (BM-7 manufactured by Topcon Corporation).
また、視認性の判定は、表 1の場合と同様の方法で判定した。  Visibility was determined by the same method as in Table 1.
[0060] [表 1] [0060] [Table 1]
Figure imgf000023_0001
Figure imgf000023_0001
Figure imgf000024_0001
Figure imgf000024_0001
Figure imgf000024_0002
Figure imgf000024_0002
Figure imgf000025_0001
Figure imgf000025_0001
Figure imgf000026_0001
Figure imgf000026_0001
[0064] この評価結果から以下のことが分かる。 [0064] From the evaluation results, the following can be understood.
表 1の実験例 100から 104を参照すると、視野半値角が小さくなるにつれて明度変 化率が大きくなり、視認性が良くなることが分かる。具体的には、透過率調整体のドッ トサイズが 450 /z mの場合には、視野半値角が 2. 1以下の場合に目視された。  Referring to Experimental Examples 100 to 104 in Table 1, it can be seen that as the half-value angle of view decreases, the brightness change rate increases and the visibility improves. Specifically, when the dot size of the transmittance adjusting body was 450 / zm, it was visually observed when the half-value angle of view was 2.1 or less.
また、実験例 104から 106を参照すると、透過率調整体のドットサイズが大きくなる につれて、明度変化率が大きくなることが分力る。  Further, referring to Experimental Examples 104 to 106, it can be seen that the brightness change rate increases as the dot size of the transmittance adjusting body increases.
したがって、透過率調整体のドットサイズが 500 μ m以下であり、かつ視野半値角 が 2. 5° 以上であれば、明度変化率は透過率調整体が目視されない程度の小さな 値をとる。つまり、明度変化率を 3以下とすることができ、光射出面から透過率調整体 が視認されることを防止できると考えられる。つまり、透過率調整体が視認されること を防止でき、より輝度分布のむらを低減させることができる。  Therefore, if the dot size of the transmittance adjuster is 500 μm or less and the viewing half-value angle is 2.5 ° or more, the brightness change rate is small enough that the transmittance adjuster is not visible. In other words, the brightness change rate can be set to 3 or less, and it is considered that the transmittance adjusting body can be prevented from being visually recognized from the light exit surface. That is, the transmittance adjusting body can be prevented from being visually recognized, and the unevenness of the luminance distribution can be further reduced.
[0065] 表 2の実験例 200から 206を参照すると、全光線透過率が大きくなるにつれて明度 変化率が大きくなり、視認性が良くなることが分かる。具体的には、透過率調整体のド ットサイズが 450 mの場合には、全光線透過率が 95. 5以上の場合に透過率調整 体が目視された。 [0065] Referring to Experimental Examples 200 to 206 in Table 2, it can be seen that as the total light transmittance increases, the lightness change rate increases and the visibility improves. Specifically, when the dot size of the transmittance adjusting body was 450 m, the transmittance adjusting body was visually observed when the total light transmittance was 95.5 or more.
また、実験例 206と 207を参照すると、透過率調整体のドットサイズが大きくなると、 明度変化率が大きくなる。  Further, referring to Experimental Examples 206 and 207, the brightness change rate increases as the dot size of the transmittance adjusting body increases.
したがって、透過率調整体のドットサイズが 500 μ m以下であり、かつ全光線透過 率が 90%以下であれば、明度変化率は透過率調整体が目視されない程度の小さな 値をとる。つまり、明度変化率を 3以下とすることができ、光射出面から透過率調整体 が視認されることを防止できると考えられる。つまり、透過率調整体が視認されること を防止でき、より輝度分布のむらを低減させることができる。  Therefore, if the dot size of the transmittance adjuster is 500 μm or less and the total light transmittance is 90% or less, the lightness change rate is small enough that the transmittance adjuster is not visible. In other words, the brightness change rate can be set to 3 or less, and it is considered that the transmittance adjusting body can be prevented from being visually recognized from the light exit surface. That is, the transmittance adjusting body can be prevented from being visually recognized, and the unevenness of the luminance distribution can be further reduced.
[0066] また、表 3の実験例 300から 304を参照すると、ヘイズが小さくなるにつれて明度変 化率が大きくなり、視認性が良くなることが分かる。具体的には、透過率調整体のドッ トサイズが 450 μ mの場合には、ヘイズが 77%以下の場合に目視された。 [0066] Further, referring to Experimental Examples 300 to 304 in Table 3, it can be seen that as the haze decreases, the brightness change rate increases and the visibility improves. Specifically, when the dot size of the transmittance adjusting body was 450 μm, it was visually observed when the haze was 77% or less.
また、実験例 304と 305を参照すると、透過率調整体のドットサイズが大きくなると、 明度変化率が大きくなることが分力る。  In addition, referring to Experimental Examples 304 and 305, it can be seen that the brightness change rate increases as the dot size of the transmittance adjuster increases.
したがって、透過率調整体のドットサイズが 500 μ m以下であり、かつヘイズが 85% 以上であれば、明度変化率は透過率調整体が目視されない程度の小さな値をとる。 つまり、明度変化率を 3以下とすることができ、光射出面から透過率調整体が視認さ れることを防止できると考えられる。つまり、透過率調整体が視認されることを防止で き、より輝度分布のむらを低減させることができる。 Therefore, the dot size of the transmittance adjuster is 500 μm or less and the haze is 85%. If it is more than the above, the lightness change rate takes a small value such that the transmittance adjusting body is not visually observed. In other words, the brightness change rate can be set to 3 or less, and it is considered that the transmittance adjusting body can be prevented from being visually recognized from the light exit surface. That is, the transmittance adjusting body can be prevented from being visually recognized, and the unevenness of the luminance distribution can be further reduced.
[0067] 表 4から、視野半値角及びヘイズが小さくなるにつれて明度変化率が大きくなり、視 認性が良くなることが分かる。具体的には、透過率調整体のドットサイズが 450 mの 場合には、視野半値角が 1. 9以下であり、かつヘイズが 79. 5%以下の場合に目視 された。 [0067] From Table 4, it can be seen that as the half-value angle and haze of the field of view decrease, the rate of change in brightness increases and the visibility is improved. Specifically, when the dot size of the transmittance adjusting body was 450 m, the viewing half-value angle was 1.9 or less and the haze was 79.5% or less.
また、表 4の実験例 400から 402を参照すると、視野半値角及びヘイズが大きくなる と、輝度が大きくなることが分力る。  Also, referring to Experimental Examples 400 to 402 in Table 4, it can be seen that the luminance increases as the half-value angle and haze increase.
したがって、透過率調整体のドットサイズが 500 μ m以下の場合において、視野半 値角が 2. 5° 以上であり、かつヘイズが 85%以上であれば、明度変化率は透過率 調整体が目視されない程度の小さな値をとる。つまり、明度変化率を 3以下とすること ができ、光射出面力も透過率調整体が視認されることを防止できると考えられる。つ まり、透過率調整体が視認されることを防止でき、輝度分布のむらをより低減させるこ とがでさる。  Therefore, when the dot size of the transmittance adjuster is 500 μm or less, if the half-value angle of view is 2.5 ° or more and haze is 85% or more, the rate of change in brightness will be Take a small value that is not visible. In other words, the brightness change rate can be set to 3 or less, and the light exit surface force can be prevented from being visually recognized by the transmittance adjusting body. In other words, the transmittance adjusting body can be prevented from being visually recognized, and the unevenness of the luminance distribution can be further reduced.
さらに、視野半値角とヘイズの双方を高くすると、透過率調整体のドットが目視され ないとともに、輝度を高く保つことができることが分かる。  Furthermore, it can be seen that when both the viewing half-value angle and haze are increased, the dots of the transmittance adjusting body are not visually observed and the luminance can be kept high.
以上より本発明の効果は明らかである。  From the above, the effects of the present invention are clear.
[0068] ここで、上記実施形態では、拡散フィルムの光学特性を所定範囲とすることで、面 状照明装置から射出される光を、平均輝度を低下させることなく透過率調整体が視 認されることを防止したが、本発明はこれに限定されない。 [0068] Here, in the above-described embodiment, by setting the optical characteristics of the diffusion film within a predetermined range, the transmittance adjusting body is recognized without reducing the average luminance of the light emitted from the planar illumination device. However, the present invention is not limited to this.
[0069] 透過率調整体 26の最大寸法に応じて、拡散フィルム 14と透過率調整体 26との配 置間隔を考慮することでも、輝度分布のむらを改善することができる。 [0069] The unevenness of the luminance distribution can also be improved by considering the arrangement interval between the diffusion film 14 and the transmittance adjusting body 26 in accordance with the maximum dimension of the transmittance adjusting body 26.
具体的には、透過率調整体 26の最大寸法を 500 m以下にし、かつ透過率調整 体 26と拡散フィルム 14との距離 Dと、前記透過率調整体 26の最大寸法 Sとの比率 D ZSが 3. 0以上とする。  Specifically, the maximum dimension of the transmittance adjusting body 26 is set to 500 m or less, and the ratio between the distance D between the transmittance adjusting body 26 and the diffusion film 14 and the maximum dimension S of the transmittance adjusting body 26 D ZS Is 3.0 or more.
ここで、比率 DZSは、透過率調整体 26の最大寸法に応じて、透過率調整体 26と 拡散フィルム 14との距離 Dを調整することによって設定することができる。 Here, the ratio DZS depends on the maximum size of the transmittance adjusting body 26 and the transmittance adjusting body 26. It can be set by adjusting the distance D to the diffusion film 14.
[0070] このように、透過率調整体 26のドットサイズを目視されづらい程度に小さくし、かつ 透過率調整体 26と拡散フィルム 14との距離が上記規定を満たすように配置すること によって、平均輝度低下を防止しつつ (輝度を維持した状態で)、透過率調整体 26 が視認されることも防止された均一な光源を得ることができる。 [0070] In this way, by reducing the dot size of the transmittance adjusting body 26 so that it is difficult to see, and arranging the distance between the transmittance adjusting body 26 and the diffusion film 14 so as to satisfy the above definition, the average is obtained. It is possible to obtain a uniform light source that prevents the transmittance adjusting body 26 from being visually recognized while preventing a decrease in luminance (while maintaining the luminance).
[0071] 透過率調整体 26と拡散フィルム 14との距離 Dの調整方法としては、アクリル板等を 透過率調整体 26が配置される透過率調整部材 28と拡散フィルム 14との間に設けて 行ってもよぐ透過率調整部材 28と拡散フィルム 14とからなる光学部材の端部 (縁） にスぺーサを配置し、空気によって行ってもよぐ拡散フィルムを支持する支持体を 設け、その支持体の厚みを調整することにより行ってもよい。 [0071] As a method of adjusting the distance D between the transmittance adjusting body 26 and the diffusion film 14, an acrylic plate or the like is provided between the transmittance adjusting member 28 on which the transmittance adjusting body 26 is disposed and the diffusion film 14. A spacer is arranged at the end (edge) of the optical member composed of the transmittance adjusting member 28 and the diffusion film 14 that can be performed, and a support body that supports the diffusion film that can be performed by air is provided. You may carry out by adjusting the thickness of the support body.
比率 DZSの数値範囲は、本発明者によって見出されたものであり、以下に示す実 施例 2の結果に基づくものである。  The numerical range of the ratio DZS was found by the present inventor and is based on the results of Example 2 shown below.
実施例 2  Example 2
[0072] 以下、具体的実施例とともに、本発明の光学部材及びそれを用いる面状照明装置 についてより詳細に説明する。  [0072] Hereinafter, the optical member of the present invention and the planar lighting device using the same will be described in more detail with specific examples.
[0073] 上述した実施例 1と同様に、透過率調整部材及び拡散フィルムを積層してなる光学 部材を用いたバックライトユニットを作製し、視認限界値を決定した。ここで、ノ ックラ イトユニットの構成、形状、視認限界値の決定方法は上述の実施例 1と同様であるの で詳細な説明は省略する。  [0073] In the same manner as in Example 1 described above, a backlight unit using an optical member formed by laminating a transmittance adjusting member and a diffusion film was produced, and the visibility limit value was determined. Here, the configuration of the knock light unit, the shape, and the method for determining the visual recognition limit value are the same as those in the first embodiment, and thus detailed description thereof is omitted.
官能評価、明度及び明度変化率を測定して算出した結果、透過率調整体が視認さ れるバックライトユニットの明度変化率は、 3. 0より大きくなり、透過率調整体が視認さ れないバックライトユニットの明度変化率は、 3. 0以下であった。  As a result of measuring and calculating sensory evaluation, brightness, and brightness change rate, the brightness change rate of the backlight unit in which the transmittance adjustment body is visually recognized is greater than 3.0, and the transmittance adjustment body is not visible. The brightness change rate of the light unit was 3.0 or less.
以上より、本実施例においても、上記実施例 1と同様に、視認限界値の明度変化率 は 3. 0となる。  As described above, also in this embodiment, as in the first embodiment, the lightness change rate of the visual recognition limit value is 3.0.
[0074] 次に、透過率調整体の寸法 (ドットサイズ)の異なる透過率調整部材と、光学特性の 異なる拡散フィルムとを異なる間隔で積層してなる光学部材を用いたバックライトュ- ットを作製し、それぞれのノ ックライトユニットについて光出射面上の透過率調整体に つ!、ての視認性を評価した。 本実施例では、透過率調整体のドットサイズ Sは 60 μ m≤S≤450 μ mの範囲で、 透過率調整部材と拡散フィルムとの距離 Dは、 200 μ m≤D≤ 5000 μ mの範囲で調 整した (設定した)。 [0074] Next, a backlight unit using an optical member formed by laminating a transmittance adjusting member having different dimensions (dot size) of the transmittance adjusting body and a diffusion film having different optical characteristics at different intervals is manufactured. For each knocklight unit, the visibility of the transmittance adjusting body on the light exit surface was evaluated. In this example, the dot size S of the transmittance adjusting body is in the range of 60 μm ≤ S ≤ 450 μm, and the distance D between the transmittance adjusting member and the diffusion film is 200 μm ≤ D ≤ 5000 μm. Adjusted (set) the range.
また、透過率調整部材と拡散フィルムとの距離 Dは、スぺーサ及び拡散フィルム支 持体 (図示せず）により拡散フィルムを保持することで調整した。  The distance D between the transmittance adjusting member and the diffusion film was adjusted by holding the diffusion film with a spacer and a diffusion film support (not shown).
[0075] 表 5に、透過率調整体のドットサイズ Sと透過率調整部材と拡散フィルムとの距離 D を変化させたバックライトユニットについて、測定し算出した明度変化率と視認性の判 定の結果とを、各バックライトユニットのドットサイズ Sと距離 Dとともに示す。  [0075] Table 5 shows the measured brightness change rate and visibility judgment for the backlight unit in which the dot size S of the transmittance adjusting body and the distance D between the transmittance adjusting member and the diffusion film were changed. The results are shown together with the dot size S and distance D of each backlight unit.
[0076] [表 5] [0076] [Table 5]
Figure imgf000031_0001
Figure imgf000031_0001
[0077] この評価結果から以下のことが分かる。 [0077] The following can be understood from the evaluation results.
実験例 500から 504を参照すると、距離 Dを小さくするにつれて、比率 DZSの値が 小さくなつて、明度変化率 dB/dxが大きくなり視認性が悪くなる、つまり、透過率調整 体が視認されやすくなることが分かる。具体的には、透過率調整体のドットサイズが 4 50 μ mの場合には、比率 DZSが 2. 2以下の場合に透過率調整体が目視される。 また、実験例 505と 506を参照すると、透過率調整体のドットサイズが 130 mの場 合には、比率 DZSが 1. 5以下の場合に透過率調整体が目視されることが分かる。  Referring to Experimental Examples 500 to 504, as the distance D decreases, the ratio DZS value decreases, the brightness change rate dB / dx increases and the visibility deteriorates.In other words, the transmittance adjustment body is easily visible. I understand that Specifically, when the dot size of the transmittance adjusting body is 450 μm, the transmittance adjusting body is visually observed when the ratio DZS is 2.2 or less. Further, referring to Experimental Examples 505 and 506, it can be seen that when the dot size of the transmittance adjusting body is 130 m, the transmittance adjusting body is visually observed when the ratio DZS is 1.5 or less.
[0078] また、実験例 507から 509を参照すると、距離 Dを小さくするにつれて、比率 DZS の値が小さくなつて、明度変化率 dB/dxが大きくなり視認性が視認性が悪くなる、つ まり、透過率調整体が視認されやすくなることが分かる。具体的には、透過率調整体 のドットサイズが 60 /z mの場合には、比率 DZSが 1. 7以下の場合に透過率調整体 が目視されることが分かる。 [0078] Further, referring to Experimental Examples 507 to 509, as the distance D is decreased, the value of the ratio DZS is decreased, the brightness change rate dB / dx is increased, and the visibility is deteriorated. It can be seen that the transmittance adjusting body is easily visible. Specifically, when the dot size of the transmittance adjusting body is 60 / zm, it can be seen that the transmittance adjusting body is visually observed when the ratio DZS is 1.7 or less.
実験例 110から透過率調整体のドットサイズが 600 μ mの場合には、距離 Dを 160 O /z mとかなり離しても明度変化率 dB/dxの値は 3. 0を超えており、透過率調整体が 目視されることが分かる。このことより、ノツクユニットを薄型にするためには、透過率 調整体のドットサイズは 500 μ m以下である必要があると考えられる。  From Experiment 110, when the dot size of the transmittance adjustment body is 600 μm, even if the distance D is far away from 160 O / zm, the value of the rate of change in brightness dB / dx exceeds 3.0. It can be seen that the rate adjuster is visible. This suggests that the dot size of the transmittance adjusting body needs to be 500 μm or less in order to make the knock unit thin.
[0079] したがって、透過率調整部材のドットサイズが 500 μ m以下であり、かつ透過率調 整体と拡散フィルムとの距離 Dと、ドットサイズ Sとの比率 DZSが 3. 0以上であれば、 明度変化率が 3. 0以下となり、透過率調整体が輝度むらとして視認されることはない と考えられる、つまり、透過率調整体が視認されることを防止でき、輝度分布のむらを より低減させることができる。 [0079] Therefore, if the dot size of the transmittance adjusting member is 500 μm or less and the ratio DZS between the distance D between the transmittance adjusting body and the diffusion film and the dot size S is 3.0 or more, The lightness change rate is 3.0 or less, and it is considered that the transmittance adjustment body is not visually recognized as uneven brightness.In other words, it is possible to prevent the transmittance adjustment body from being visually recognized and to further reduce uneven brightness distribution. be able to.
以上より、本発明の効果は明らかである。  From the above, the effects of the present invention are clear.
[0080] 以上、本発明に係る光学部材及びそれを用いた面状照明装置について詳細に説 明したが、本発明は、以上の実施形態に限定されるものではなぐ図 5A乃至図 5Cに 示すように、反射シート 22と導光板 18の間にもプリズムシート 19を設けてもよい。 図 5Aは、反射シート 22と導光板 18の傾斜面 18dとの間にプリズムシート 19が配置 される様子を示す概略断面図であり、図 5Bは、反射シート 22と導光板 18の傾斜面 1 8dとの間に配置されるプリズムシート 19を導光板側から見た概略平面図であり、図 5 cは、プリズムシートの概略横断面図である。 [0080] Although the optical member and the planar lighting device using the optical member according to the present invention have been described in detail above, the present invention is not limited to the above embodiment, and is shown in FIGS. 5A to 5C. As described above, the prism sheet 19 may also be provided between the reflection sheet 22 and the light guide plate 18. 5A is a schematic cross-sectional view showing a state in which the prism sheet 19 is disposed between the reflective sheet 22 and the inclined surface 18d of the light guide plate 18. FIG. 5B is an inclined surface 1 of the reflective sheet 22 and the light guide plate 18. FIG. 5 is a schematic plan view of the prism sheet 19 disposed between the light guide plate side and the light guide plate side. c is a schematic cross-sectional view of a prism sheet.
反射シート 22と導光板 18の傾斜面 18dとの間に設けられるプリズムシート 19は、プ リズム 23aの延在する方向が導光板 18の平行溝 18fと垂直になるように配置されると ともに、プリズム 19aの頂角が導光板 18の傾斜面 18bと対向するように配置してもよ い。  The prism sheet 19 provided between the reflection sheet 22 and the inclined surface 18d of the light guide plate 18 is arranged so that the direction in which the prism 23a extends is perpendicular to the parallel groove 18f of the light guide plate 18, You may arrange | position so that the apex angle of the prism 19a may oppose the inclined surface 18b of the light-guide plate 18. FIG.
[0081] ここではプリズムシートを用いたが、プリズムシートと同様の効果を有する光学部材 を用いても良ぐレンズ効果を有する光学部材、例えば、レンチキュラーレンズ、凹レ ンズ、凸レンズ、ピラミッド型などの光学部材が規則的に配置されたシートを設けても 良い。  [0081] Although a prism sheet is used here, an optical member having a lens effect that may be an optical member having the same effect as the prism sheet, such as a lenticular lens, a concave lens, a convex lens, a pyramid type, etc. A sheet in which optical members are regularly arranged may be provided.
なお、図示例においては、プリズムシート 16及び 17を用いる力 導光板 18の平行 溝 18fによる光射出面 18aにおける輝度が均一化である場合には、プリズムシート 19 はもちろん不要であるし、プリズムシート 16及び 17のどちらか一方、または両方を用 いなくても良い。高価なプリズムシートの使用枚数を減らし、あるいは、プリズムシート の使用をやめることにより、装置コストを低減させることができる。  In the illustrated example, when the brightness on the light exit surface 18a by the parallel grooves 18f of the force light guide plate 18 using the prism sheets 16 and 17 is uniform, the prism sheet 19 is of course unnecessary, and the prism sheet One or both of 16 and 17 need not be used. By reducing the number of expensive prism sheets used or by stopping the use of prism sheets, the device cost can be reduced.
[0082] 図 1に示す実施形態では、光透過率を有する光学部材として透明フィルム 9を選択 し、その上に透過率調整体 26を配置して透過率調整部材 28とした力 光透過性を 有する光学部材として、拡散フィルム、プリズムシートまたは導光板を選択してもよい 。すなわち、拡散フィルムやプリズムシート、または導光板の表面に直接透過率調整 体を配置することもできる。この場合には、立体物に直接印刷することができるインク ジェット印刷によって透過率調整体を配置することが好適である。 In the embodiment shown in FIG. 1, a transparent film 9 is selected as an optical member having light transmittance, and a transmittance adjusting member 26 is arranged thereon to form a transmittance adjusting member 28. A diffusing film, a prism sheet, or a light guide plate may be selected as the optical member. That is, the transmittance adjusting body can be arranged directly on the surface of the diffusion film, the prism sheet, or the light guide plate. In this case, it is preferable to arrange the transmittance adjusting body by ink jet printing that can directly print on a three-dimensional object.
このように、透過率調整体を拡散フィルム、プリズムシートまたは導光板の表面に設 けることで、透過率調整体を透明フィルムに配置して透過率調整部材を構成する必 要がなくなる。したがって、透明フィルムを省略することができ、ノ ックライトユニットを 構成する層の構造をより簡単にすることができ、製造コストも削減することができる。  Thus, by providing the transmittance adjusting body on the surface of the diffusion film, the prism sheet or the light guide plate, it is not necessary to configure the transmittance adjusting member by arranging the transmittance adjusting body on the transparent film. Therefore, the transparent film can be omitted, the structure of the layers constituting the knock light unit can be simplified, and the manufacturing cost can be reduced.
[0083] また、透過率調整部材 28は、導光板と拡散フィルムの間や、拡散フィルムとプリズ ムシートの間に配置された場合には透過率調整部材配置後の製造工程において配 置位置がずれる可能性がある。透過率調整部材は輝線や暗線など輝度分布のむら を低減させるため、その配置位置のずれを防止することは重要である。 透過率調整体を直接導光板の光射出面に配置した場合は、透過率調整部材の配 置位置のずれを防止することができる。さらに、ノ ックライトユニットの組立工程におい て透過率調整体のァライメント (配置合わせ)をとる必要がなくなる。 [0083] Further, when the transmittance adjusting member 28 is disposed between the light guide plate and the diffusion film or between the diffusion film and the prism sheet, the position of the transmittance adjusting member 28 is shifted in the manufacturing process after the transmittance adjusting member is disposed. there is a possibility. Since the transmittance adjusting member reduces unevenness of the luminance distribution such as bright lines and dark lines, it is important to prevent displacement of the arrangement position. When the transmittance adjusting body is arranged directly on the light exit surface of the light guide plate, it is possible to prevent a shift in the arrangement position of the transmittance adjusting member. Furthermore, it is not necessary to align the transmittance adjusting body in the assembly process of the knocklight unit.
[0084] また、透過率調整体の印刷と併せてァライメントメークを、透過率調整体を配置する 領域以外に付与してもよい。そうすることで、ノ ックライトユニットの組立工程における ァライメント (位置合わせ）が容易になる。  [0084] In addition to the printing of the transmittance adjusting body, the alignment makeup may be applied to a region other than the region where the transmittance adjusting body is disposed. This facilitates alignment in the assembly process of the knocklight unit.
[0085] 以下、本発明の面状照明装置に好適に用いることができる導光板の他の形状につ いて詳細に説明する。  Hereinafter, other shapes of the light guide plate that can be suitably used in the planar illumination device of the present invention will be described in detail.
図 1に示す実施形態では、平行溝 18fの断面形状を、先端部分が三角形をなし、 その基端部分が矩形をなすホームベース形状としたが、本発明においては、これに 限定されず、先端部分が傾斜して交わり、先端部分に繋がる基端部分の傾斜が先端 部分の傾斜よりも急峻であれば、どのような形状でも良い。すなわち、平行溝 18fの 断面形状を、先端部分において光射出面 18aに向力つて、その間隔が狭くなり、頂 点で交わる 1対の輪郭線で構成し、各輪郭線を、光射出面 18aに垂直な線に対する 傾斜角度が変化する部分を有し、頂点に近い先端側 (先端面 18h)より、頂点から遠 V、平行溝の基端側 (基端面 18i)の方が鋭角となる形状であればよ!、。  In the embodiment shown in FIG. 1, the cross-sectional shape of the parallel groove 18f is a home base shape in which the tip end portion is a triangle and the base end portion is a rectangle. Any shape may be used as long as the portions intersect with each other and the inclination of the proximal end portion connected to the distal end portion is steeper than the inclination of the distal end portion. That is, the cross-sectional shape of the parallel groove 18f is directed to the light exit surface 18a at the tip portion, and the distance between the parallel grooves 18f is narrowed to form a pair of contour lines that intersect at the apex. The shape has a part where the angle of inclination with respect to a line perpendicular to the vertical axis changes, and is farther from the apex (front end face 18h) near the apex, and the base end side (base end face 18i) of the parallel groove has an acute angle. If so!
言い換えれば、平行溝 18fの断面形状において、頂点に近い先端側 (先端面 18h )の輪郭線が光射出面 18aとなす傾斜角（最大傾斜角 Φπι)よりも、頂点から遠い平 行溝の基端側 (基端面 18i)の輪郭線が光射出面 18aとなす傾斜角（傾斜角 Φη)の 方が大きい形状であればよい。例えば、図 6Αに示すように、平行溝 18fの 1対の先 端面 40を双曲線形状に、図 6Bに示すように、平行溝 18fの 1対の先端面 42を楕円 形状にすることができる。あるいは、導光板 18の平行溝 18fの 1対の先端面の断面形 状は懸垂線形状でも良い。  In other words, in the cross-sectional shape of the parallel groove 18f, the base of the parallel groove farther from the vertex than the inclination angle (maximum inclination angle Φπι) formed by the contour line on the tip side (tip surface 18h) close to the vertex is the light exit surface 18a. Any shape may be used as long as the inclination angle (inclination angle Φη) formed by the contour line on the end side (base end face 18i) and the light exit surface 18a is larger. For example, as shown in FIG. 6B, the pair of front end faces 40 of the parallel grooves 18f can be formed into a hyperbola shape, and as shown in FIG. 6B, the pair of front end faces 42 of the parallel grooves 18f can be formed into an oval shape. Alternatively, the cross-sectional shape of the pair of tip surfaces of the parallel grooves 18f of the light guide plate 18 may be a catenary line shape.
[0086] また、本発明にお 、ては、平行溝の断面形状にお!、て、平行溝の頂点、すなわち 最深部 (平行溝を形成する側壁の接続部）が尖点となるような形状にすることもできる 。すなわち、平行溝の 1対の先端面の断面形状が、互いに交わる先鋭な 1つの交点 を有する、平行溝の中心を通って導光板の光射出面に垂直な中心線に対して対称 な 2つの曲線または直線の一部から形成することができる。本発明においては、導光 板の平行溝の断面形状が、上記いずれの形状であっても、導光板の光射出面から 均一な光を出射させることができる。 [0086] In the present invention, the cross-sectional shape of the parallel groove is such that the apex of the parallel groove, that is, the deepest part (the connection part of the side wall forming the parallel groove) is a cusp. It can also be shaped. That is, two cross-sectional shapes of a pair of front end surfaces of the parallel grooves are symmetrical with respect to a center line perpendicular to the light exit surface of the light guide plate through the center of the parallel grooves having one sharp intersection that intersects each other. It can be formed from a part of a curve or straight line. In the present invention, the light guide Even if the cross-sectional shape of the parallel groove of the plate is any of the above shapes, uniform light can be emitted from the light exit surface of the light guide plate.
[0087] 図 6Cには、平行溝の 1対の先端面 50の断面形状力 互いに交わる先鋭な 1つの 交点を有する、平行溝 18fの中心を通って導光板の光射出面に垂直な中心線に対 して対称な 2つの曲線の一部力もなる場合の一例を示す。図 6Cに示す導光板 18は 、平行溝 18fの中心を通って導光板 18の光射出面 18aに垂直な中心線 Xに対して 1 対の先端面 50となる対称な 2つの曲線 51a及び 51bが円弧の場合である。この場合 は、図 6Cに示すように、平行溝 18fを形成する一方の側壁に対応する円弧 51aの中 心の位置と他方の側壁に対応する円弧 5 lbの中心の位置が異なるように形成される 。これにより、円弧状の両側壁が交わる部分 52は、図 6Cに示すように尖った形状と なる。  [0087] In FIG. 6C, the cross-sectional shape force of the pair of front end surfaces 50 of the parallel groove has a single intersection point that intersects each other, and passes through the center of the parallel groove 18f and is perpendicular to the light exit surface of the light guide plate An example of the case where the partial force of two curves symmetric with respect to is also shown. The light guide plate 18 shown in FIG. 6C has two symmetrical curves 51a and 51b that form a pair of front end surfaces 50 with respect to a center line X perpendicular to the light exit surface 18a of the light guide plate 18 through the center of the parallel groove 18f. Is an arc. In this case, as shown in FIG. 6C, the center position of the arc 51a corresponding to one side wall forming the parallel groove 18f is different from the center position of the arc 5 lb corresponding to the other side wall. The As a result, the portion 52 where the arc-shaped side walls meet each other has a sharp shape as shown in FIG. 6C.
[0088] また、図 6Dには、平行溝の 1対の先端面 53の断面形状が、互いに交わる先鋭な 1 つの交点を有する、平行溝の中心を通って導光板の光射出面に垂直な中心線に対 して対称な 2つの曲線の一部力もなる場合の更に別の例を示した。図 6Dに示した導 光板 18は、平行溝 18fの中心を通って導光板 18の光射出面 18aに垂直な中心線 X に対して 1対の先端面 53となる対称な 2つの曲線 54a及び 54bが放物線の場合であ る。図 6Dにおいては、平行溝 18fの一方の側壁に対応する放物線 54aの焦点と、他 方の側壁に対応する放物線 54bの焦点とが互いに異なるように、平行溝 18fの 1対の 先端面 53が形成される。  [0088] Also, in FIG. 6D, the cross-sectional shape of the pair of front end faces 53 of the parallel grooves is perpendicular to the light exit surface of the light guide plate through the center of the parallel grooves having one sharp intersection that intersects each other. Yet another example is shown in which the partial force of two curves that are symmetrical about the center line is also present. The light guide plate 18 shown in FIG. 6D has two symmetrical curves 54a and a pair of front end faces 53 with respect to a center line X passing through the center of the parallel groove 18f and perpendicular to the light exit surface 18a of the light guide plate 18. 54b is a parabola. In FIG. 6D, the pair of front end surfaces 53 of the parallel groove 18f are arranged so that the focal point of the parabola 54a corresponding to one side wall of the parallel groove 18f and the focal point of the parabola 54b corresponding to the other side wall are different from each other. It is formed.
[0089] 図 6Dに示すように、平行溝 18fの 1対の先端面 53の断面形状が、交点 56で交わる 2つの曲線 54a及び 54bから形成される場合において、平行溝 18fの一方の側壁に 対応する曲線 54aの、交点（尖点） 56における接線と、他方の側壁に対応する曲線 5 4bの、交点 56における接線が互いになす角 Θは、 90度以下が好ましぐ 60度以下 力 り一層好ましい。  [0089] As shown in FIG. 6D, when the cross-sectional shape of the pair of tip surfaces 53 of the parallel groove 18f is formed by two curves 54a and 54b that intersect at the intersection 56, it is formed on one side wall of the parallel groove 18f. The angle Θ between the tangent line at the intersection (point) 56 of the corresponding curve 54a and the tangent line at the intersection 56 of the curve 54b corresponding to the other side wall Θ is preferably less than 60 degrees. Even more preferred.
[0090] 図 6では、平行溝の断面形状において、平行溝の 1対の先端面を形成する曲線が 、平行溝の中心に向力つて凹状の導光板の例を示したが、これらとは異なる本発明 に好適に用 、ることができる導光板の別の態様を図 7A及び図 7Bに示す。図 7Aは、 平行溝 18fの 1対の先端面 60の断面形状力 平行溝 18fの中心に向かって凸の 2つ の曲線 61a及び 61bから形成される導光板の例であり、図 7Bは、平行溝 18fの 1対 の先端面 63の断面形状が、平行溝 18fの中心に向力つて凸の曲線 64a及び 64bと 凹の曲線 66a及び 66bを組み合わせた曲線力 形成される導光板の例である。図 7 A及び図 7Bに示したような断面形状の平行溝を有する導光板も、輝線の発生を抑制 しつつ光射出面力 十分な輝度の光を出射することができる。 FIG. 6 shows an example of a light guide plate that is concave in the cross-sectional shape of the parallel grooves, in which the curves forming a pair of front end surfaces of the parallel grooves are directed toward the center of the parallel grooves. FIG. 7A and FIG. 7B show another embodiment of the light guide plate that can be suitably used for different present inventions. Figure 7A shows the cross-sectional shape force of a pair of tip surfaces 60 of the parallel groove 18f. 7B is an example of a light guide plate formed from the curved lines 61a and 61b of FIG. 7. FIG. 7B shows a curved line 64a and 64b in which the cross-sectional shape of the pair of tip surfaces 63 of the parallel groove 18f is convex toward the center of the parallel groove 18f. This is an example of a light guide plate formed by combining a curved force 66a and 66b and a curved force. A light guide plate having parallel grooves having a cross-sectional shape as shown in FIGS. 7A and 7B can also emit light with sufficient light emission surface strength while suppressing generation of bright lines.
[0091] また、図 5及び図 7では、平行溝の断面形状において、平行溝の先端部分の 1対の 基端面を、先端面 18h及び平行面 18gと接する光射出面 18aに対して平行で対称な 垂直な線分とした力 平行溝 18fの断面形状が、光射出面 18aに向力つて、その間 隔が狭くなり、頂点で交わる 1対の輪郭線で構成され、各輪郭線が、光射出面に垂直 な線に対する傾斜角度が変化する部分を有し、頂点に近い先端側 (先端面)より、頂 点から遠 、平行溝の基端側 (基端面)の方が鋭角となる形状であればよぐ例えば、 平行溝の 1対の先端面の断面形状が、三角形の場合は、図 8Aに示すように、平行 溝の 1対の基端面 70の断面形状を、光射出面 18aに対して垂直かつ光源の中心を 通過する線とのなす角が先端面 18hよりも鋭角な所定角度の傾斜を有する線分 (斜 辺)で形成してもよい。また、平行溝の各基端面の断面形状は、直線に限定されず曲 線も用いることができ、図 8Bに示すように、平行溝 18fの 1対の基端面 72の断面形状 を平行溝 18fの中心に向力つて凹状の曲線としてもよい。ここで、曲線としては、双曲 線形状、楕円形状、放物線形状等、平行溝の 1対の先端面に用いる各種の曲線を 用!/、ることができる。 Further, in FIGS. 5 and 7, in the cross-sectional shape of the parallel groove, the pair of base end surfaces of the front end portion of the parallel groove are parallel to the light exit surface 18a in contact with the front end surface 18h and the parallel surface 18g. Symmetrical vertical line segment The cross-sectional shape of the parallel groove 18f is directed to the light exit surface 18a, and the distance between the parallel grooves 18f is narrowed.It is composed of a pair of contour lines that intersect at the apex. It has a part where the inclination angle with respect to a line perpendicular to the exit surface changes, and it is farther from the apex than the tip side (tip surface) close to the apex, and the base end side (base end surface) of the parallel groove has an acute angle. For example, if the cross-sectional shape of the pair of tip surfaces of the parallel grooves is a triangle, the cross-sectional shape of the pair of base end surfaces 70 of the parallel grooves is changed to the light exit surface 18a as shown in FIG. It is formed by a line segment (the hypotenuse) that has an inclination of a predetermined angle that is perpendicular to the line that passes through the center of the light source and is acute than the tip surface 18h. May be. The cross-sectional shape of each base end face of the parallel groove is not limited to a straight line, and a curved line can also be used. As shown in FIG. 8B, the cross-sectional shape of the pair of base end faces 72 of the parallel groove 18f is changed to the parallel groove 18f. A concave curve may be formed by directing force toward the center. Here, as the curve, various curves used for a pair of tip surfaces of parallel grooves, such as a hyperbolic shape, an elliptical shape, and a parabolic shape, can be used.
[0092] 平行溝の形状は、これに限定されず、上述した 1対の先端面の形状と 1対の基端面 の形状を各種組み合わせた形状等の種々の形状とすることができる。また、平行溝 の 1対の先端面と 1対の基端面の大きさは、平行溝の内部に光源が配置できればよく 、 1対の先端面と 1対の基端面の境界位置 (接触位置）は特に限定されない。  [0092] The shape of the parallel grooves is not limited to this, and can be various shapes such as a combination of the shapes of the pair of distal end surfaces and the pair of proximal end surfaces described above. In addition, the size of the pair of distal end surfaces and the pair of proximal end surfaces of the parallel grooves is sufficient if the light source can be arranged inside the parallel grooves, and the boundary position (contact position) between the pair of distal end surfaces and the pair of proximal end surfaces Is not particularly limited.
[0093] ここで、平行溝の 1対の先端面と 1対の基端面との継ぎ目（接続部分)、平行溝の 1 対の基端面と平行面との継ぎ目及び平行面と傾斜面との継ぎ目は、 R>0. 01 [mm ]となる滑らかな形状とすることが好ま 、。継ぎ目を滑らかな形状とすることで継ぎ目 での光の乱反射を防止し、輝線の発生、輝度むらの発生を防止することができる。  [0093] Here, a joint (connection portion) between a pair of distal end surfaces and a pair of proximal end surfaces of a parallel groove, a joint between a pair of proximal end surfaces and a parallel surface of parallel grooves, and a parallel surface and an inclined surface The seam should have a smooth shape with R> 0.01 [mm]. By making the seam a smooth shape, irregular reflection of light at the seam can be prevented, and generation of bright lines and uneven brightness can be prevented.
[0094] さらに、平行溝の側面（1対の先端面及び 1対の基端面)を除く導光板の表面、例え ば、光射出面及び Zまたは傾斜面に棒状光源の軸にその稜が平行な複数の所定形 状の微小なプリズムを形成することが好まし 、。平行溝の側面（1対の先端面及び 1 対の基端面)を除く導光板の表面に所定形状の微小なプリズムを多数形成すること で、ノ ックライトなどの面状照明装置を構成する場合に、プリズムシートを不要とする ことができ、面状照明装置としての光の利用効率向上させることができ、装置のコン パクト化、ひいては、コストの低減を図ることができる。なお、多数の所定形状の微小 なプリズムを、傾斜面及び射出面のいずれかに形成するのがより好ましいが、さらに、 傾斜面及び光射出面の両方にこのようなプリズムを形成するのがより好ましい。 [0094] Further, the surface of the light guide plate excluding the side surfaces of the parallel grooves (a pair of distal end surfaces and a pair of proximal end surfaces), for example For example, it is preferable to form a plurality of minute prisms having a predetermined shape whose ridges are parallel to the axis of the rod-shaped light source on the light exit surface and the Z or inclined surface. When configuring a planar lighting device such as a knocklight by forming a large number of small prisms of a predetermined shape on the surface of the light guide plate excluding the side surfaces of the parallel grooves (a pair of front end surfaces and a pair of base end surfaces). In addition, the prism sheet can be omitted, the light use efficiency as the planar illumination device can be improved, the device can be made compact, and the cost can be reduced. It is more preferable to form a large number of minute prisms having a predetermined shape on either the inclined surface or the exit surface, but it is more preferable to form such prisms on both the inclined surface and the light exit surface. preferable.
ここで、傾斜面に形成するプリズムは、頂角 0 を 100° ≤ Θ ≤140° とすること  Here, for the prism formed on the inclined surface, the apex angle 0 shall be 100 ° ≤ Θ ≤ 140 °
pi Pi  pi Pi
が好ましい。また、光射出面に形成するプリズムは、頂角 0 を 40° ≤ Θ ≤70° と p2 p2 することがより好まし!/、。  Is preferred. In addition, it is more preferable that the prism formed on the light exit surface has apex angle 0 of 40 ° ≤ Θ ≤70 ° and p2 p2! /.
[0095] また、図 6から図 8に示す導光板では、 1対の傾斜面と平行溝の 1対の基端面との 間にそれぞれ 1対の平行面を設けたが、本発明において、平行面は、必ずしも設け る必要はなぐ図 9に示すように、平行面を設けず、傾斜面 80と平行溝 18fの基端面 18iとを直接接続させた構造としてもよい。  [0095] In the light guide plate shown in Figs. 6 to 8, a pair of parallel surfaces is provided between the pair of inclined surfaces and the pair of base end surfaces of the parallel grooves. As shown in FIG. 9, the surface does not necessarily have to be provided, and a parallel surface may not be provided, and the inclined surface 80 and the base end surface 18i of the parallel groove 18f may be directly connected.
[0096] 本発明に好適に用いることができる導光板においては、図 10に示すように、ある中 心線 Xにおいて網点の密度が高くその中心線 Xから両側（中心線に対して垂直方向 )に向かうにしたがって次第に網点の密度が低くなるような網点パターン 92を導光板 18の光射出面 18aに、例えば、印刷により形成してもよい。このような網点パターン 9 2を、網点パターンの中心線 Xが導光板 18の平行溝の中心線に対応する位置と一 致するように、導光板 18の光射出面 18aに形成することにより、導光板 18の光射出 面 18aにおける輝線の発生やムラを抑制することができる。また、網点パターン 92を 導光板 18に印刷する代わりに、網点パターンが形成された薄いシートを光射出面上 に積層しても良い。網点の形状は、矩形、円形、楕円形などを任意の形状にすること ができ、網点の密度は、輝線の強さや広がりに応じて適宜選択することができる。ま た、このような網点パターンを印刷により形成する代わりに、網点パターンに対応する 部分を砂擦り面として荒らしてもよい。このような砂擦り面は、導光板の平行溝の最深 部や側壁に形成してもよい。 [0097] ここで、光射出面から出射される光の輝度分布は、導光板の平行溝の先端部分の 形状に大きく依存するため、導光板の平行溝の形状を、上述の本発明で示した形状 になるように設計するだけで、導光板の光射出面における輝度を最適に調整して均 一化できる。 In the light guide plate that can be suitably used in the present invention, as shown in FIG. 10, the density of halftone dots is high at a certain center line X, and both sides from the center line X (in the direction perpendicular to the center line). ) May be formed on the light exit surface 18a of the light guide plate 18 by, for example, printing. Such a halftone dot pattern 92 is formed on the light exit surface 18a of the light guide plate 18 so that the center line X of the halftone dot pattern matches the position corresponding to the center line of the parallel groove of the light guide plate 18. Thus, generation of bright lines and unevenness on the light exit surface 18a of the light guide plate 18 can be suppressed. Further, instead of printing the halftone dot pattern 92 on the light guide plate 18, a thin sheet on which the halftone dot pattern is formed may be laminated on the light emitting surface. The shape of the halftone dots can be any shape, such as a rectangle, a circle, or an ellipse, and the density of the halftone dots can be appropriately selected according to the intensity and spread of the bright line. Further, instead of forming such a halftone dot pattern by printing, a portion corresponding to the halftone dot pattern may be roughened as a rubbing surface. Such a rubbing surface may be formed at the deepest part or the side wall of the parallel groove of the light guide plate. Here, since the luminance distribution of the light emitted from the light exit surface largely depends on the shape of the tip portion of the parallel groove of the light guide plate, the shape of the parallel groove of the light guide plate is shown in the above-described present invention. By simply designing it so that it has a uniform shape, the brightness on the light exit surface of the light guide plate can be optimally adjusted and leveled.
一例としては、導光板の平行溝の断面形状を双曲線にした場合は、平行溝に対応 する部分における相対輝度のピーク値が、傾斜背面部力 の出射光によって形成さ れる相対輝度の平均値の 10倍以下となり、光射出面力もの輝度が略均一となる。一 方、平行溝の断面形状が半円形または放物線形の従来の導光板においては、平行 溝の中心部分、すなわち、光源の直上の位置において相対輝度が高くなり、輝線が 発生する。すなわち、従来の平行溝の断面形状が半円形状または放物線形状の導 光板においては、光射出面における輝度が均一ではない。  As an example, when the cross-sectional shape of the parallel groove of the light guide plate is a hyperbola, the peak value of the relative luminance in the portion corresponding to the parallel groove is the average value of the relative luminance formed by the emitted light of the inclined back surface force. The luminance is 10 times or less, and the luminance of the light exit surface force becomes substantially uniform. On the other hand, in a conventional light guide plate in which the cross-sectional shape of the parallel grooves is semicircular or parabolic, the relative luminance increases at the central portion of the parallel grooves, that is, the position directly above the light source, and bright lines are generated. That is, in the conventional light guide plate having a semicircular or parabolic cross-sectional shape of the parallel grooves, the luminance on the light exit surface is not uniform.
[0098] また、平行溝の断面形状が三角形状の導光板においては、中心部分の相対輝度 は低くなるため、頂点を所定の幅で平坦にする力 比較的曲率半径の小さな曲面に することによって、光射出面における輝度を均一化することができる。 [0098] Further, in the light guide plate having a triangular cross-sectional shape of the parallel grooves, the relative luminance of the central portion is low, so that the force for flattening the apex with a predetermined width is made a curved surface with a relatively small radius of curvature. The luminance on the light exit surface can be made uniform.
ここで、平行溝の頂点を所定の幅で平坦にする場合は、平坦部分の長さに応じて、 導光板の平行溝に対応する部分における相対輝度が変化する。このため、本発明に おいては、平行溝の最深部の平端部分を長くすることで輝度を高めることができるが 、長すぎると輝線となる恐れがあるため、平端部分の長さは、冷陰極管の直径の 20 %以下とすることが好ましぐ 10%以下とすることがより好ましい。  Here, when flattening the apex of the parallel groove with a predetermined width, the relative luminance in the portion corresponding to the parallel groove of the light guide plate changes according to the length of the flat portion. For this reason, in the present invention, the brightness can be increased by lengthening the flat end portion of the deepest portion of the parallel groove. However, if the length is too long, a bright line may be formed. It is preferably 20% or less of the diameter of the cathode tube, more preferably 10% or less.
[0099] また、導光板の表面において、輝度と照度は略同様に扱うことができる。本発明に おいては、照度においても同様の傾向があると推測される。したがって、導光板の平 行溝の形状を本発明で示した形状になるように設計することで、導光板の光射出面 における照度についても均一化できると考えられる。 [0099] Further, on the surface of the light guide plate, luminance and illuminance can be handled in substantially the same manner. In the present invention, it is presumed that there is a similar tendency in illuminance. Therefore, it is considered that the illuminance on the light exit surface of the light guide plate can be made uniform by designing the shape of the parallel grooves of the light guide plate to be the shape shown in the present invention.
なお、平行溝の先端部分の頂部 (最深部)の断面形状が、平行溝の中心線に対し て対称にするように先鋭な 1つの交点において、面取りされた平坦状、もしくは、丸め られた円形状のみならず、楕円形状、放物線状、または双曲線状であっても良いの はもちろんである。さらに、これにカ卩え、上述したように、平行溝の先端部分の頂部（ 最深部）を砂擦り面とすることにより、照度または輝度のピーク値を低減するようにして も良い。 Note that the cross-sectional shape of the top (deepest part) of the tip of the parallel groove is chamfered flat or rounded at one sharp intersection so as to be symmetric with respect to the center line of the parallel groove. Of course, not only the shape but also an elliptical shape, a parabolic shape, or a hyperbolic shape may be acceptable. Furthermore, in consideration of this, as described above, the peak value of illuminance or luminance is reduced by making the top part (deepest part) of the tip part of the parallel groove a sand rubbing surface. Also good.
[0100] 以上から、本発明に好適に用いることができる導光板においては、導光板 18の光 射出面 18aにおける平行溝 18f以外、すなわち傾斜面 18dに相当する部分 (第 2部 分）に形成される輝度の平均値に対する、導光板 18の光射出面 18aにおける平行溝 18fに相当する部分 (第 1部分）に形成される輝線のピーク値 (輝度のピーク値)の比 に応じて、導光板 18の平行溝 18fの先端形状の先細化を行う、すなわち、この比の 値に応じて、導光板 18の平行溝 18fの先端形状の先細化の程度を制御する。なお、 この場合においては、後述する第 2の形態の場合のように、この比は、 3以下、より好 ましくは、 2以下とするのが好ましい。  [0100] From the above, in the light guide plate that can be suitably used in the present invention, it is formed on the light emission surface 18a of the light guide plate 18 other than the parallel grooves 18f, that is, on the portion corresponding to the inclined surface 18d (second portion). Depending on the ratio of the peak value (luminance peak value) of the bright line formed in the portion corresponding to the parallel groove 18f (first portion) on the light exit surface 18a of the light guide plate 18 to the average luminance value, The tip shape of the parallel groove 18f of the optical plate 18 is tapered, that is, the degree of tapering of the tip shape of the parallel groove 18f of the light guide plate 18 is controlled according to the value of this ratio. In this case, the ratio is preferably 3 or less, more preferably 2 or less, as in the case of the second embodiment described later.
[0101] なお、この比は、ノ ックライトユニット 2の厚み (導光板 18の光射出面 18aと拡散シ ート 14との間の距離)や、ノ ックライトユニット 2において使用される拡散シート 14の 拡散効率や枚数、プリズムシート 16、 17及び 19の拡散効率や使用枚数等に応じて 、設定するのが好ましい。すなわち、ノ ックライトユニット 2の厚み (導光板 18の光射 出面 18aと拡散シート 14との間の距離)がある程度厚く（または大きく）できる場合や、 ノ ックライトユニット 2において使用される拡散シート 14の拡散効率が高ぐ使用枚数 を多くできる場合や、プリズムシート 16、 17及び 19の拡散効率が高ぐ使用枚数を多 くできる場合には、導光板 18の光射出面 18aから射出された照明光の拡散 (ミキシン グなど）を十分に行うことができるので、高コストとはなるが、導光板 18の光射出面 18 aの第 2部分の輝度の平均値に対する、導光板 18の光射出面 18aの第 1部分の輝度 のピーク値の比を、ある程度大きく設定することができる。しかし、そうでない場合には 、低コストィ匕できるが、この比の値を小さく設定する必要がある。  [0101] Note that this ratio depends on the thickness of the knock light unit 2 (the distance between the light exit surface 18a of the light guide plate 18 and the diffusion sheet 14) and the diffusion sheet used in the knock light unit 2. It is preferable to set according to the diffusion efficiency and the number of sheets 14 and the diffusion efficiency and the number of sheets used of the prism sheets 16, 17 and 19. That is, when the thickness of the knock light unit 2 (distance between the light emitting surface 18a of the light guide plate 18 and the diffusion sheet 14) can be increased to a certain extent (or larger), or the diffusion sheet used in the knock light unit 2 When the number of used sheets with high diffusion efficiency of 14 can be increased, or when the number of sheets used with high diffusion efficiency of prism sheets 16, 17, and 19 can be increased, the light is emitted from the light exit surface 18a of the light guide plate 18. Although light diffusion (mixing, etc.) can be performed sufficiently, the cost is high, but the light of the light guide plate 18 with respect to the average value of the luminance of the second part of the light exit surface 18a of the light guide plate 18a is high. The ratio of the luminance peak values of the first portion of the exit surface 18a can be set to be large to some extent. However, if this is not the case, the cost can be reduced, but the value of this ratio needs to be set small.
[0102] なお、導光板 18の平行溝 18fの断面形状において、平行溝 18fの先細化を行う先 端部分は、棒状光源 12の中心力 光射出面 18aに向力 垂線 (X)に対する角度が、 両側で 90度以内となる部分、より好ましくは、 60度以内となる部分とするのが好まし い。すなわち、導光板 18の光射出面 18aの平行溝 18fに相当する第 1部分の輝度の ピーク値を低減するために、平行溝 18fの先細化を行う部分は、平行溝 18fの全体で も良いが、ピーク値の低減ィ匕が可能であれば、所定の先端部分で良い。  [0102] Note that, in the cross-sectional shape of the parallel groove 18f of the light guide plate 18, the tip end portion where the parallel groove 18f is tapered has an angle with respect to the central force light exit surface 18a of the rod-shaped light source 12 and the perpendicular force (X). It is preferable that the portion is within 90 degrees on both sides, more preferably, the portion is within 60 degrees. That is, in order to reduce the luminance peak value of the first portion corresponding to the parallel grooves 18f of the light exit surface 18a of the light guide plate 18, the entire portion of the parallel grooves 18f may be tapered. However, if the peak value can be reduced, a predetermined tip portion may be used.
[0103] さらに、導光板の平行溝の形状を、光射出面に向力つて、その間隔が狭くなり、頂 点で交わる 1対の輪郭線で構成され、各輪郭線が、光射出面に垂直な線に対する傾 斜角度が変化する部分を有し、頂点に近い先端側（1対の各先端面)より、頂点から 遠 ヽ平行溝の基端側（ 1対の各基端面)の方が鋭角となる形状とすることで、より輝度 むらを減らすことができ、出射効率も向上させることができる。つまり、平行溝の断面 形状を他の双曲線、放物線、他の曲面の傾斜した線分の最大傾き角 Φπιに対し、他 の傾き角 Φη( > Φπι)を有する曲線の組み合わせとすることで、より輝度むらを減ら すことができ、出射効率も向上させることができる。 [0103] Further, the shape of the parallel grooves of the light guide plate is directed toward the light exit surface, and the distance between the grooves is reduced. Consists of a pair of contour lines intersecting at a point, and each contour line has a portion whose inclination angle changes with respect to a line perpendicular to the light exit surface, and from the tip side (a pair of tip surfaces) near the apex By making the base end side (one pair of base end faces) of the distant parallel groove away from the apex a sharper angle, uneven brightness can be further reduced and the emission efficiency can be improved. In other words, the cross-sectional shape of the parallel groove is a combination of a curve having another inclination angle Φη (> Φπι) with respect to the maximum inclination angle Φπι of another hyperbola, parabola, or other curved line. Brightness unevenness can be reduced and the emission efficiency can be improved.
また、平行溝の側面（1対の先端面及び 1対の基端面)を除く導光板の表面、例え ば、光射出面及び Ζまたは傾斜面に直接棒状光源の軸にその溝が平行なプリズム を刻設してもよい。  In addition, the surface of the light guide plate excluding the side surfaces of the parallel grooves (a pair of front end surfaces and a pair of base end surfaces), for example, a light emitting surface and a prism whose grooves are parallel to the axis of the rod-shaped light source directly on the flange or inclined surface. May be engraved.
例えば、図 11A及び Βに示すように導光板 18の傾斜面 18dにプリズム 25を直接形 成してもよぐ図 12に示すように導光板 18の光射出面 18aにプリズム 26及び傾斜面 18dにプリズム 25を形成してもよい。  For example, the prism 25 may be formed directly on the inclined surface 18d of the light guide plate 18 as shown in FIG. 11A and Β, and the prism 26 and the inclined surface 18d are formed on the light exit surface 18a of the light guide plate 18 as shown in FIG. Alternatively, the prism 25 may be formed.
このように、平行溝の側面（1対の先端面及び 1対の基端面)を除く導光板の表面に プリズムを形成することで、プリズムシートを配置した場合と同様の効果を得ることが できる。さらに、プリズムシートを設ける必要がなくなるので、シートを配置することで、 形成される空隙により生じる光の減衰 (輝度の低下)を無くすことができ、面状照明装 置としての光の利用効率つまり光の出射効率をプリズムシートを配置する場合よりも 高くすることができる。さら〖こ、プリズムシートを設ける必要がないので、装置をより小 型化 (薄型化)することもできる。  Thus, by forming the prism on the surface of the light guide plate excluding the side surfaces of the parallel grooves (one pair of front end surfaces and one pair of base end surfaces), it is possible to obtain the same effect as when a prism sheet is disposed. . Furthermore, since it is not necessary to provide a prism sheet, the arrangement of the sheet can eliminate light attenuation (decrease in luminance) caused by the formed gap, and the light use efficiency as a planar illumination device, that is, The light emission efficiency can be made higher than when a prism sheet is arranged. Furthermore, since there is no need to provide a prism sheet, the apparatus can be made smaller (thinner).
ここでは、光射出面に向力つて、その間隔が狭くなり、頂点で交わる 1対の輪郭線で 構成され、各輪郭線が、光射出面に垂直な線に対する傾斜角度が変化する部分を 有し、頂点に近い先端側（1対の先端面)より、頂点から遠い平行溝の基端側（1対の 基端面)の方が鋭角となる形状を有する導光板を用いたが、これに限定されず、例え ば、三角形、双曲線等の光射出面に向力う先端部分に向かって細くしていく形状の 平行溝を有する導光板を用いる場合も平行溝の側面（1対の先端面及び 1対の基端 面)を除く導光板の表面にプリズムを形成することで、上記と同様の効果を得ることが できる。 [0105] ここで、傾斜面に形成するプリズムは、頂角 0 を 100° ≤ Θ ≤140° とすること Here, the distance between the light exit surfaces becomes narrower, and it is composed of a pair of contour lines that intersect at the apex, and each contour line has a portion where the inclination angle with respect to a line perpendicular to the light exit surface changes. In addition, a light guide plate having a shape in which the base end side (a pair of base end surfaces) of the parallel groove far from the apex has a sharper angle than the front end side (a pair of front end surfaces) close to the apex was used. For example, when using a light guide plate having a parallel groove that is thinned toward the tip portion that faces the light exit surface, such as a triangle or a hyperbola, the side surfaces of the parallel grooves (a pair of tip surfaces) The same effects as described above can be obtained by forming prisms on the surface of the light guide plate except for the pair of base end surfaces). [0105] Here, for the prism formed on the inclined surface, the apex angle 0 should be 100 ° ≤ Θ ≤140 °
pi Pi  pi Pi
が好ましい。また、光射出面に形成するプリズムは、頂角 0 を 40° ≤ Θ ≤70° と  Is preferred. In addition, the prism formed on the light exit surface has an apex angle 0 of 40 ° ≤ Θ ≤ 70 °.
p2 p2  p2 p2
することが好ましい。形成するプリズムの頂角 Θ 及び頂角 Θ を上記範囲とすること  It is preferable to do. The apex angle Θ and apex angle Θ of the prism to be formed are within the above range.
pi p2  pi p2
で、面状照明装置としての出射効率をより好適に向上させることができる。  Thus, the emission efficiency as the planar illumination device can be improved more suitably.
[0106] また、導光板の光射出面が全て同一平面を形成するように導光板を複数並列して 配置することによって、大サイズの光射出面を持つ導光板を構成することもできる。こ のように導光板を並列して配置したときには、ある導光板の傾斜面と、それに隣接す る導光板の傾斜面との連結部分において滑らかな平面または曲面が形成されるよう に、導光板の傾斜面の傾斜角度を調整することができる。つまり、隣接する導光板の それぞれの傾斜面によって形成される面がアーチ型になるように形成することができ る。  In addition, a light guide plate having a large light exit surface can be configured by arranging a plurality of light guide plates in parallel so that the light exit surfaces of the light guide plate all form the same plane. When the light guide plates are arranged in parallel in this way, the light guide plate is formed so that a smooth flat surface or curved surface is formed at the connecting portion between the inclined surface of a certain light guide plate and the inclined surface of the light guide plate adjacent thereto. The inclination angle of the inclined surface can be adjusted. That is, the surface formed by the inclined surfaces of the adjacent light guide plates can be formed in an arch shape.
大サイズの光射出面を持つ導光板を用いることにより、大サイズの光照射面を持つ ノ ックライトユニットとすることができるので、大サイズの表示画面を持つ液晶表示装 置に適用することができる。特に、壁掛けテレビなどの壁掛けタイプの液晶表示装置 に好適に適用することができる。  By using a light guide plate with a large light exit surface, a knock light unit with a large light irradiation surface can be obtained, so it can be applied to a liquid crystal display device having a large display screen. it can. In particular, it can be suitably applied to a wall-mounted liquid crystal display device such as a wall-mounted television.
[0107] 複数の導光板を連結して大サイズの光射出面を持つ導光板を形成する場合には、 別々に成形した導光板の薄肉部を連結して形成することができる。しかし、これ以外 にも、製造効率の観点からは、必要な画面サイズに相当する導光板を形成するのに 必要な数の導光板を一体で成形することができる。  [0107] When a plurality of light guide plates are connected to form a light guide plate having a large light exit surface, the thin portions of the separately formed light guide plates can be connected. However, in addition to this, from the viewpoint of manufacturing efficiency, as many light guide plates as necessary to form a light guide plate corresponding to the required screen size can be integrally formed.
[0108] また、最も外側に配置される導光板の側面に反射板を配置してもよ!/、。このような反 射板を側面に配置することで導光板の側面力 の光の漏出を防止することができ、 光利用効率を一層高めることができる。なお、反射板は、前述した反射シート、または リフレクタと同様な材料を用いて形成することができる。  [0108] In addition, a reflector may be disposed on the side surface of the light guide plate disposed on the outermost side! /. By disposing such a reflecting plate on the side surface, light leakage due to the side force of the light guide plate can be prevented, and light utilization efficiency can be further enhanced. The reflecting plate can be formed using the same material as the reflecting sheet or reflector described above.
[0109] 図 13は、透過率調整部材と拡散フィルムとを有する本発明の光学部材を用いたタ ンデム方式の面状照明装置の概略を示す図である。図 13Aは面上照明装置の斜視 図であり、図 13Bは面上照明装置を拡大した断面図であり、図 13Cは反射シートを 取り除いた状態で図 13Aに示す面上照明装置を背面側力 見た下面図である。な お、タンデム方式の面状照明装置においても、図 1に示す面状装置と同様の効果を 得ることができた。 FIG. 13 is a diagram showing an outline of a tandem surface illumination device using the optical member of the present invention having a transmittance adjusting member and a diffusion film. 13A is a perspective view of the surface lighting device, FIG. 13B is an enlarged cross-sectional view of the surface lighting device, and FIG. 13C is a rear side force of the surface lighting device shown in FIG. 13A with the reflective sheet removed. FIG. Note that the tandem-type planar lighting device has the same effect as the planar device shown in FIG. I was able to get it.
[0110] タンデム方式の面状照明装置 210は、棒状光源 122と、くさび型の複数の導光板 2 10と、リフレクタ 20と、反射シート 120と、透過率調整部材 28と、拡散フィルム 124と、 プリズムシート 16, 17とを有する。なお、上述したように、ここでも透過率調整体 26と 拡散フィルム 14を併せて光学部材と 、う。  [0110] The tandem planar illumination device 210 includes a rod-shaped light source 122, a plurality of wedge-shaped light guide plates 210, a reflector 20, a reflection sheet 120, a transmittance adjusting member 28, a diffusion film 124, Prism sheets 16 and 17. As described above, here, the transmittance adjusting body 26 and the diffusion film 14 are collectively referred to as an optical member.
図 1に示す実施形態と同様な部材には同じ符号を付し、説明を適宜省略する。  The same members as those in the embodiment shown in FIG.
[0111] 棒状光源 12は、その形状が棒状 (線状)の光源であり、液晶表示パネル（図示せず )を照明するために用いられる。光源 12は、導光板 18に形成された平行溝 18f内に 配置される。棒状光源 12は、導光板 120が複数連結して用いられることに伴って複 数個用いられる。各棒状光源 12は、長手方向を平行にそろえ、導光板とそれに隣接 する導光板の間に配置される。 [0111] The rod-shaped light source 12 is a rod-shaped (linear) light source, and is used to illuminate a liquid crystal display panel (not shown). The light source 12 is disposed in a parallel groove 18 f formed in the light guide plate 18. A plurality of rod-shaped light sources 12 are used as a plurality of light guide plates 120 are connected and used. Each rod-shaped light source 12 is arranged between the light guide plate and the light guide plate adjacent to the light guide plate, with the longitudinal directions aligned in parallel.
棒状光源 12は、図 1に示す実施形態と同様に、例えば、冷陰極管、蛍光管、 LED (発光ダイオード)などを用いることができる。  As the rod-shaped light source 12, for example, a cold cathode tube, a fluorescent tube, an LED (light emitting diode), or the like can be used, as in the embodiment shown in FIG.
[0112] 導光板 120は、矩形状の光射出面 120aと、光射出面 120aの一辺力もその対辺に 向かうに従って板厚が薄くなるように、光射出面 120aに対して傾斜する傾斜背面 12 Ocと、上記一辺を含む面であり、光射出面 120aに垂直な面上に形成される光入射 面 120bと、上記対辺を含む面であり、光射出面 120aに垂直な面上に形成される端 面とを備える。ここでは傾斜背面 120cを平面として形成する力 曲面としてもよい。 棒状光源 12の長手方向に対して垂直な導光板 120の断面は、光入射面 120bが 広ぐ端面に向かうに従って狭くなるような形状である。 [0112] The light guide plate 120 includes a rectangular light exit surface 120a and an inclined back surface that is inclined with respect to the light exit surface 120a so that the thickness of one side of the light exit surface 120a decreases toward the opposite side. A light incident surface 120b formed on a surface perpendicular to the light emission surface 120a and a surface including the opposite side and formed on a surface perpendicular to the light emission surface 120a. And an end face. Here, the inclined back surface 120c may be a force curved surface forming a flat surface. The cross section of the light guide plate 120 perpendicular to the longitudinal direction of the rod-shaped light source 12 is shaped so that the light incident surface 120b becomes narrower toward the wide end surface.
複数の導光板 120は、それに隣接する導光板の端面と導光板 120の光出射面 12 Oaとが連結されて、配置される。各導光板の光射出面は同一平面を形成するため、 大サイズの光射出面を持つ導光板を構成することができる。  The plurality of light guide plates 120 are arranged by connecting the end face of the light guide plate adjacent to the light guide plates 120 and the light output surface 12 Oa of the light guide plate 120. Since the light exit surfaces of the respective light guide plates form the same plane, a light guide plate having a large size light exit surface can be configured.
[0113] 透過率調整部材 28は、導光板 18から出射される光の輝度むらを低減させるもので あり、光透過性を有する光学部材である透明フィルム 29と、所定の密度分布をもって 透明フィルム 29の表面に配置される複数の透過率調整体 26とを有する。 [0113] The transmittance adjusting member 28 reduces unevenness in luminance of light emitted from the light guide plate 18, and includes a transparent film 29 which is an optical member having light transmittance, and a transparent film 29 having a predetermined density distribution. And a plurality of transmittance adjusting bodies 26 arranged on the surface of the substrate.
透明フィルム 29は、フィルム状の形状を有し、導光板 18と拡散フィルム 14の間に配 置される。 透過率調整体の最大寸法を 500 m以下であり、透過率調整体 26のドットサイズ は目視されづらい程度に小さい。 The transparent film 29 has a film shape and is disposed between the light guide plate 18 and the diffusion film 14. The maximum size of the transmittance adjusting body is 500 m or less, and the dot size of the transmittance adjusting body 26 is so small that it is difficult to see.
[0114] 拡散フィルム 14は、導光板 18の光射出面 18aから出射する光を拡散して均一化す るための光学部材である。拡散フィルム 14は、導光板 210の光射出面 18aから出射 した光をより均一な出射光にするために、光学特性が規定される。 The diffusion film 14 is an optical member for diffusing and making uniform the light emitted from the light exit surface 18a of the light guide plate 18. The diffusing film 14 has optical characteristics in order to make the light emitted from the light exit surface 18a of the light guide plate 210 more uniform.
具体的には、拡散フィルムの光学特性は、視野半値角ならば 2. 5° 以上、全光線 透過率ならば 90%以下、またはヘイズならば 85%以上に設定する。あるいは、これ ら光学特性の 2つ以上を組み合わせてもよい。例えば、ヘイズ値を 85%以上、かつ 視野半値角を 2. 5° 以上と設定してもよい。  Specifically, the optical properties of the diffusion film are set to 2.5 ° or more for a half-field angle, 90% or less for total light transmittance, or 85% or more for haze. Alternatively, two or more of these optical characteristics may be combined. For example, the haze value may be set to 85% or more, and the viewing half-value angle may be set to 2.5 ° or more.
このような構成を採用することにより、ノ ックライトユニットの光射出面上の輝度むら を改善することができる。つまり、透過率調整体が視認されることを防止しつつ輝度む らを低減させることができる。  By adopting such a configuration, it is possible to improve uneven brightness on the light exit surface of the knocklight unit. That is, it is possible to reduce luminance unevenness while preventing the transmittance adjusting body from being visually recognized.
[0115] また、これに限定されず、上述の面状照明装置 10と同様に、透過率調整体 26の最 大寸法を 500 m以下とし、さら〖こ、透過率調整体 26の最大寸法を Sとし、透過率調 整部材 28と拡散フィルム 14との距離を Dとしたときに 3≤DZSとすることによつても、 輝度むらを改善することができる。つまり、透過率調整体が視認されることを防止しつ つ輝度むらを低減させることができる。 [0115] Further, the present invention is not limited to this, and similarly to the above-described planar lighting device 10, the maximum dimension of the transmittance adjusting body 26 is set to 500 m or less, and the maximum dimension of the transmittance adjusting body 26 is set to 500. By setting S to 3≤DZS where D is the distance between the transmittance adjusting member 28 and the diffusion film 14, brightness unevenness can also be improved. That is, it is possible to reduce the uneven brightness while preventing the transmittance adjusting body from being visually recognized.
[0116] 反射シート 124は、導光板 120の傾斜背面 120cと、棒状光源 122を覆うように配置 される。反射シート 124は、棒状光源 122から放射される光の一部を反射して、導光 板 120に入射させるものであり、光の利用効率を向上させる。 The reflection sheet 124 is disposed so as to cover the inclined back surface 120c of the light guide plate 120 and the rod-shaped light source 122. The reflection sheet 124 reflects part of the light emitted from the rod-shaped light source 122 and makes it incident on the light guide plate 120, and improves the light use efficiency.
反射シート 124は、光を反射することができればどのような材料でもよぐ例えば、榭 脂シートや鏡面シートなどにより形成することができる。  The reflection sheet 124 may be made of any material as long as it can reflect light. For example, the reflection sheet 124 can be formed of a resin sheet, a specular sheet, or the like.
[0117] 棒状光源 122から放射される光のうち、光入射面 120bから導光板 210の内部に入 射した光は、導光板 120の傾斜背面 120cで反射した後、光射出面 18aから出射す る。 [0117] Of the light emitted from the rod-shaped light source 122, the light that enters the light guide plate 210 from the light incident surface 120b is reflected by the inclined back surface 120c of the light guide plate 120 and then exits from the light exit surface 18a. The
一方、棒状光源 122から放射される光のうち、導光板 120の内部に直接入射しない 光は、棒状光源 122を覆うように形成された反射シート 124によりー且反射して、導 光板 120の内部に入射して光射出面 18aから出射する。こうして、導光板 120の光射 出面 120aから出射される光の輝度が均一な光が放射される。 On the other hand, of the light emitted from the rod-shaped light source 122, the light that does not directly enter the light guide plate 120 is reflected by the reflection sheet 124 formed so as to cover the rod-shaped light source 122, and the light of the light guide plate 120 It enters the interior and exits from the light exit surface 18a. Thus, the light from the light guide plate 120 Light having a uniform brightness is emitted from the exit surface 120a.
[0118] 導光板 120を複数連結して大サイズの光射出面を持つ導光板は、大サイズの光照 射面を持つバックライトユニットに用いることができる。さらに、このバックライトユニット は大サイズの表示画面を持つ液晶表示装置に適用することができる。 [0118] A light guide plate having a large light emission surface by connecting a plurality of light guide plates 120 can be used in a backlight unit having a large light emission surface. Furthermore, this backlight unit can be applied to a liquid crystal display device having a large-sized display screen.
したがって、図 13に示す実施形態の導光板やそれを用いたバックライトユニットは、 特に、壁掛けテレビなどの壁掛けタイプの液晶表示装置に好適に適用することがで きる。  Therefore, the light guide plate of the embodiment shown in FIG. 13 and the backlight unit using the light guide plate can be suitably applied particularly to a wall-mounted liquid crystal display device such as a wall-mounted television.
[0119] 以上、本発明に係る光学部材及びそれを用いた面状照明装置並びに液晶表示装 置について詳細に説明した力 本発明は、以上の実施形態に限定されるものではな ぐ本発明の要旨を逸脱しない範囲において、各種の改良や変更を行ってもよい。 産業上の利用可能性  [0119] As described above, the optical member according to the present invention, the planar illumination device using the optical member, and the power explained in detail for the liquid crystal display device. The present invention is not limited to the above-described embodiments. Various improvements and changes may be made without departing from the scope of the invention. Industrial applicability
[0120] 本発明の光学部材は、透過率調整体が視認されることなぐ輝度むらを低減させる ことができる。それゆえ、液晶ディスプレイ、オーバーヘッドプロジェクター、広告用電 飾看板などに利用される面状照明装置 (バックライトユニット)などの光射出面に配置 される光学部材として利用することができる。 [0120] The optical member of the present invention can reduce luminance unevenness without allowing the transmittance adjuster to be visually recognized. Therefore, it can be used as an optical member disposed on a light exit surface of a surface illumination device (backlight unit) used for a liquid crystal display, an overhead projector, an advertising signboard, and the like.
また、本発明の面状照明装置は、液晶ディスプレイ、オーバーヘッドプロジェクター 、広告用電飾看板などに利用される面状照明装置 (バックライトユニット)として利用 することができる。  In addition, the planar lighting device of the present invention can be used as a planar lighting device (backlight unit) used for a liquid crystal display, an overhead projector, an electric signboard for advertisement, and the like.
また、本発明の液晶表示装置は、液晶モニタ、壁掛けテレビや広告用電飾看板な どに利用することができる。  In addition, the liquid crystal display device of the present invention can be used for a liquid crystal monitor, a wall-mounted television, an advertising electric signboard, and the like.

Claims

請求の範囲 The scope of the claims
[1] 光の透過率を調整する複数の透過率調整体を光学部材の表面に配置してなる透 過率調整部材と、光を拡散して均一化する拡散フィルムとを積層してなる光学部材で あって、  [1] Optical formed by laminating a transmittance adjusting member formed by arranging a plurality of transmittance adjusting bodies for adjusting light transmittance on the surface of an optical member, and a diffusion film for diffusing and uniformizing light A member,
前記透過率調整体の最大寸法が 500 m以下であり、かつ前記拡散フィルムの視 野半値角が 2. 5° 以上である光学部材。  An optical member having a maximum dimension of the transmittance adjusting body of 500 m or less and a viewing half-value angle of the diffusion film of 2.5 ° or more.
[2] 前記拡散フィルムは、ヘイズ値が 85%以上である請求項 1に記載の光学部材。 [2] The optical member according to [1], wherein the diffusion film has a haze value of 85% or more.
[3] 光の透過率を調整する複数の透過率調整体を光学部材の表面に配置してなる透 過率調整部材と、光を拡散して均一化する拡散フィルムとを積層してなる光学部材で あって、 [3] An optical device formed by laminating a transmittance adjusting member in which a plurality of transmittance adjusting bodies for adjusting light transmittance are arranged on the surface of an optical member, and a diffusion film that diffuses and equalizes light. A member,
前記透過率調整体の最大寸法が 500 m以下であり、かつ前記拡散フィルムの全 光線透過率が 90%以下である光学部材。  An optical member having a maximum dimension of the transmittance adjusting body of 500 m or less and a total light transmittance of the diffusion film of 90% or less.
[4] 光の透過率を調整する複数の透過率調整体を光学部材の表面に配置してなる透 過率調整部材と、光を拡散して均一化する拡散フィルムとを積層してなる光学部材で あって、 [4] Optical formed by laminating a transmittance adjusting member in which a plurality of transmittance adjusting bodies for adjusting light transmittance are arranged on the surface of an optical member, and a diffusion film for diffusing and uniformizing light. A member,
前記透過率調整体の最大寸法が 500 m以下であり、かつ前記拡散フィルムのへ ィズ値が 85 %以上である光学部材。  An optical member having a maximum size of the transmittance adjusting body of 500 m or less and a haze value of the diffusion film of 85% or more.
[5] 光の透過率を調整する複数の透過率調整体を光学部材の表面に配置してなる透 過率調整部材と、光を拡散して均一化する拡散フィルムとが積層されてなる光学部 材であって、 [5] An optical device in which a transmittance adjusting member formed by arranging a plurality of transmittance adjusting bodies for adjusting light transmittance on the surface of an optical member and a diffusion film that diffuses and equalizes light are laminated. Parts,
前記透過率調整体の最大寸法 Sが 500 m以下であり、かつ前記透過率調整体と 前記拡散フィルムとの距離 Dと、前記透過率調整体の最大寸法 Sとの比率 DZSが 3 . 0以上である光学部材。  The maximum dimension S of the transmittance adjusting body is 500 m or less, and the ratio DZS between the distance D between the transmittance adjusting body and the diffusion film and the maximum dimension S of the transmittance adjusting body is 3.0 or more. An optical member.
[6] 請求項 1乃至 5のいずれか 1項に記載の光学部材と、光源と、前記光源から放射さ れる光を矩形状の平面力 前記光学部材に向けて出射する導光板とを備える面状 照明装置。 [6] A surface comprising the optical member according to any one of claims 1 to 5, a light source, and a light guide plate that emits light emitted from the light source toward the optical member in a rectangular plane force. Lighting device.
[7] 請求項 1乃至 5のいずれか 1項に記載の光学部材と、光源と、前記光源から放射さ れる光を矩形状の平面から前記光学部材に向けて出射する導光板とを備え、 前記光学部材は光透過性を有する透明フィルムである面状照明装置。 [7] The optical member according to any one of claims 1 to 5, a light source, and a light guide plate that emits light emitted from the light source from a rectangular plane toward the optical member, The planar illumination device, wherein the optical member is a transparent film having optical transparency.
[8] 請求項 1乃至 5のいずれか 1項に記載の光学部材と、光源とを備え、  [8] The optical member according to any one of claims 1 to 5, and a light source,
前記光学部材は前記光源から放射される光を矩形状の平面から前記光学部材に 向けて出射する導光板であり、  The optical member is a light guide plate that emits light emitted from the light source from a rectangular plane toward the optical member,
前記透過率調整体は導光板の光射出面上に配置される面状照明装置。  The transmittance adjusting body is a planar illumination device disposed on a light exit surface of a light guide plate.
[9] 前記導光板は、矩形状光射出面と、 [9] The light guide plate includes a rectangular light exit surface;
その一辺に略平行で矩形状光射出面の略中央部に位置する厚肉部と、 前記厚肉部に略平行に形成される 1対の薄肉端部と、  A thick wall portion substantially parallel to one side and positioned at a substantially central portion of the rectangular light exit surface; a pair of thin wall end portions formed substantially parallel to the thick wall portion;
前記厚肉部の略中央で、前記矩形状光射出面と逆側に、前記一辺と略平行に形 成され、棒状光源を収納するための平行溝と、  A parallel groove for accommodating a rod-shaped light source, formed substantially in parallel with the one side, on the opposite side of the rectangular light exit surface, at the approximate center of the thick-walled portion;
前記厚肉部力 前記一辺に略直交する方向に両側の前記 1対の前記薄肉端部の それぞれに向かって肉厚が薄くなり、前記平行溝の両側にそれぞれ 1対の傾斜背面 を形成する 1対の傾斜背面部とを有し、  The thick part force decreases in thickness toward each of the pair of thin end portions on both sides in a direction substantially perpendicular to the one side, and forms a pair of inclined back surfaces on both sides of the parallel groove 1 A pair of inclined back surfaces,
前記平行溝は、前記直交方向の断面形状において、前記矩形状光射出面に向か つて、その間隔が狭くなり、頂点で交わる 1対の輪郭線で構成され、  The parallel groove has a cross-sectional shape in the orthogonal direction, and the gap is narrowed toward the rectangular light exit surface, and is configured by a pair of contour lines that intersect at the apex,
前記直交方向の断面形状における前記平行溝の各輪郭線は、前記矩形状光射出 面に垂直な線に対する傾斜角度が変化する部分を有し、前記頂点に近い先端側より 、前記頂点から遠 、前記平行溝の基端側の方が鋭角となる請求項 6乃至 8の 、ずれ か一項に記載の面状照明装置。  Each contour line of the parallel groove in the cross-sectional shape in the orthogonal direction has a portion where an inclination angle changes with respect to a line perpendicular to the rectangular light exit surface, and is farther from the apex than the tip side near the apex. The planar illumination device according to any one of claims 6 to 8, wherein a proximal side of the parallel groove has an acute angle.
[10] 前記導光板は、矩形状光射出面と、前記光射出面の一辺からその対辺に向かうに 従って板厚が薄くなるように、前記光射出面に対して傾斜する傾斜背面と、 [10] The light guide plate includes a rectangular light emission surface, an inclined back surface that is inclined with respect to the light emission surface so that the plate thickness decreases from one side of the light emission surface toward the opposite side,
前記一辺を含む側面であり、前記光射出面に垂直な面に形成される光入射面と、 前記対辺を含む側面であり、前記光射出面に垂直な面に形成される端面とを有す る請求項 6乃至 8のいずれか一項に記載の面状照明装置。  A side surface including the one side and having a light incident surface formed on a surface perpendicular to the light emitting surface; and a side surface including the opposite side and having an end surface formed on a surface perpendicular to the light emitting surface. The planar illumination device according to any one of claims 6 to 8.
[11] 請求項 6乃至 10のいずれか一項に記載の面状照明装置力もなるノ ックライトュ-ッ トと、 [11] A knocklight boot that also has the surface illumination device power according to any one of claims 6 to 10, and
このノ ックライトユニットの光出射面側に配置される液晶表示パネルと、前記バック ライトユニット及び前記液晶表示パネルを駆動する駆動ユニットとを有する液晶表示 A liquid crystal display having a liquid crystal display panel disposed on the light emitting surface side of the knock light unit, and the driving unit for driving the backlight unit and the liquid crystal display panel.
T0l80C/900Zdf/X3d St CllSll/900Z OAV T0l80C / 900Zdf / X3d St CllSll / 900Z OAV
PCT/JP2006/308101 2005-04-19 2006-04-18 Optical member, planar illuminating device, and liquid crystal display WO2006115113A1 (en)

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WO2008062714A1 (en) * 2006-11-24 2008-05-29 Fuji Polymer Industries Co., Ltd. Light guide sheet and electronic equipment utilizing the same
WO2008062713A1 (en) * 2006-11-24 2008-05-29 Fuji Polymer Industries Co., Ltd. Light guide sheet and electronic equipment utilizing the same
CN102109712A (en) * 2009-12-29 2011-06-29 乐金显示有限公司 Light shaping film and liquid crystal display device including the same
KR20160038130A (en) * 2014-09-29 2016-04-07 엘지디스플레이 주식회사 Thin Flat Type Controlled Viewing Window Display Using The Same

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WO2008062714A1 (en) * 2006-11-24 2008-05-29 Fuji Polymer Industries Co., Ltd. Light guide sheet and electronic equipment utilizing the same
WO2008062713A1 (en) * 2006-11-24 2008-05-29 Fuji Polymer Industries Co., Ltd. Light guide sheet and electronic equipment utilizing the same
JPWO2008062713A1 (en) * 2006-11-24 2010-03-04 富士高分子工業株式会社 Light guide sheet and electronic device using the same
JP4834111B2 (en) * 2006-11-24 2011-12-14 富士高分子工業株式会社 Light guide sheet and electronic device using the same
US8177409B2 (en) 2006-11-24 2012-05-15 Fuji Polymer Industries Co., Ltd. Light guide sheet and electronic equipment utilizing the same
CN102109712A (en) * 2009-12-29 2011-06-29 乐金显示有限公司 Light shaping film and liquid crystal display device including the same
CN102109712B (en) * 2009-12-29 2014-03-12 乐金显示有限公司 Light shaping film and liquid crystal display device including same
KR20160038130A (en) * 2014-09-29 2016-04-07 엘지디스플레이 주식회사 Thin Flat Type Controlled Viewing Window Display Using The Same
KR102294293B1 (en) 2014-09-29 2021-08-27 엘지디스플레이 주식회사 Thin Flat Type Controlled Viewing Window Display Using The Same

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