WO2006085526A1 - 導光板、これを用いる面状照明装置および液晶表示装置 - Google Patents
導光板、これを用いる面状照明装置および液晶表示装置 Download PDFInfo
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- WO2006085526A1 WO2006085526A1 PCT/JP2006/302054 JP2006302054W WO2006085526A1 WO 2006085526 A1 WO2006085526 A1 WO 2006085526A1 JP 2006302054 W JP2006302054 W JP 2006302054W WO 2006085526 A1 WO2006085526 A1 WO 2006085526A1
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- WIPO (PCT)
- Prior art keywords
- guide plate
- light guide
- light
- parallel
- parallel groove
- Prior art date
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Classifications
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- 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
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- 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
- G02B6/0023—Means for improving the coupling-in of light from the light source into the light guide provided by one optical element, or plurality thereof, placed between the light guide and the light source, or around the light source
- G02B6/0031—Reflecting element, sheet or layer
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- 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
- G02B6/0055—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
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- 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
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- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
- G02F1/1336—Illuminating devices
- G02F1/133602—Direct backlight
- G02F1/133611—Direct backlight including means for improving the brightness uniformity
Definitions
- the present invention relates to a transparent light guide plate that emits uniform illumination light from a light emission surface force by diffusing light incident from a rod-shaped light source in a direction substantially parallel to the light emission surface, and 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).
- LCD liquid crystal panel
- the direct type backlight unit has a configuration in which a plurality of cold cathode tubes, which are light sources, are arranged on the back surface of the liquid crystal panel, and the interior of the housing in which the cold cathode tubes are arranged is a white reflective surface. Is illuminating.
- the liquid crystal panel needs to have a thickness of about 30 mm in the vertical direction.
- a backlight unit that can be thinned there is a so-called tandem type in which a plurality of units each having a light guide plate arranged on the side surface of an illumination light source is arranged (for example, Japanese Patent Laid-Open No. 11288611). (See the publication).
- the knock light unit can be made thin by making light incident from the side surface of the light guide plate.
- this conventional method since this conventional method has lower light use efficiency than a direct type nocturnal / crite unit, high power is required to emit light with high brightness.
- FIG. 46 is a schematic cross-sectional view of a surface light source device having a light guide plate 100 disclosed in Japanese Patent Laid-Open No. 9-304623.
- a reflective sheet 104 is disposed on the back surface of the light guide plate 100, and a transmitted light amount correction sheet is provided on the output surface of the light guide plate 100.
- 106, a light diffusion plate 108, and a prism sheet 110 are laminated.
- the light guide plate 100 has a substantially rectangular shape, and is formed using 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 assigned to the exit surface. Further, a U-shaped groove 100a that embeds the fluorescent lamp 102 is formed on the back surface of the light guide plate 100 (the surface opposite to the output surface), and the light guide plate 100 has an exit surface directly above the fluorescent lamp 102. Avoiding this, a light quantity correction surface 100b that promotes emission of illumination light is formed.
- JP-A-9-304623 discloses that a light guide plate 100 is formed by mixing fine particles, and a light amount correction surface formed on a part or all of the exit surface except directly above the fluorescent lamp 102. It is described that by promoting the emission of illumination light with 100b, the overall thickness can be reduced and unnatural luminance unevenness of the emitted light can be reduced.
- 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 cost and power consumption without reducing the amount of knocklight irradiation.
- a rectangular irradiation surface, a groove with a rectangular section cut into the center of the short side in parallel with the long side, and a long side across this groove There is disclosed a light guide plate having a back surface formed so that the plate thickness is gradually reduced in the direction of both side surfaces.
- 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) 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 is disclosed.
- JP-A-5-249320 discloses that the brightness of the display panel is kept uniform.
- a plurality of plate-like optical waveguide layers are sequentially laminated on the C-shaped high reflection layer so that the refractive index becomes higher, and the light emitted from each light emission end face is used.
- a light guide plate that brightens the light diffusion layer is disclosed.
- the recess for arranging the light source has a triangular shape.
- JP-A-2002-75036 discloses any one of a plurality of linear or rod-shaped light sources arranged in parallel, a light guide plate having a plurality of grooves for storing the light sources, and the light guide plate. Between the light diffusing and reflecting means provided on one surface side, the light diffusing means provided on the surface of the light guide plate opposite to the surface facing the light diffusing and reflecting means, and between the light source and the light diffusing means.
- a translucent reflection means provided on the light guide plate, the surface of the light guide plate facing the light diffusion means is a flat surface, and the cross-sectional shape of the light guide plate becomes thinner as the distance from the light source is increased.
- Inclined surfaces that form a curve, and the angle of inclination of the light guide plate surface relative to the back surface of the light guide plate at positions relatively close to the light source and far from the light source is ⁇ n2 and ⁇ f 2, respectively. And satisfying the relationship ⁇ ⁇ 2 ⁇ ⁇ f 2
- the tilt angle of the light guide plate surface at the thinnest portion is illuminating device becomes substantially 0 degrees is disclosed in the light guide plate.
- the light guide plates disclosed in the above-mentioned documents are all used for reducing the thickness, size and weight of the liquid crystal display device, reducing the power consumption, and reducing the cost.
- One or more grooves are provided in the part, and a rod-shaped light source is accommodated in the groove.
- the groove part force is also directed toward the end surface so that the plate thickness gradually decreases, so that the thickness can be reduced. Have achieved.
- Patent Document 1 Japanese Utility Model Publication No. 5-4133
- Patent Document 2 Japanese Patent Laid-Open No. 11-288611
- Patent Document 3 Japanese Patent Laid-Open No. 9-304623
- Patent Document 4 JP-A-8-62426
- Patent Document 5 JP-A-10-133027
- Patent Document 6 Japanese Patent Laid-Open No. 5-249320
- Patent Document 7 Japanese Patent Laid-Open No. 2001-42327
- Patent Document 8 Japanese Patent Laid-Open No. 2002-75036
- the light output from the light source (fluorescent lamp) 102 and avoiding the light source 102 such as a rough surface or a microprism surface is provided.
- Complementary front surface 100b is formed to promote the emission of illumination light that is incident on the exit surface at an angle greater than the critical angle.
- Luminance of illumination light from light guide plate 100 with light quantity correction surface 100b indicated by solid line 100b with respect to brightness N1 of illumination light from light plate N2 has little improvement effect, so brightness improvement by light quantity correction surface 100b There is a problem that uniform and high-intensity light cannot be emitted because the diffusion of the light source light is insufficient and the light source light utilization efficiency is low.
- a light source (fluorescent lamp) 102 is embedded in a groove 100a having a circular cross-sectional shape, and as shown in FIG. Therefore, in order to use it as a surface light source device, the transmitted light amount correction sheet 106, the light diffusing plate 108, the prism sheet 110, etc., which are arranged on the exit side of the light guide plate, are used. There is a problem that it is necessary to remove the natural luminance unevenness, which increases the cost of the surface light source device.
- the components on the electronic circuit board are disposed in the gap formed by inclining the back surface of the light guide plate.
- a liquid crystal display device with low power consumption can be reduced in size and weight, but the illumination light emitted from the exit surface of the light guide plate is not considered at all.
- the cross-sectional shape of the recess on the groove provided in the light guide is a parabola, so that Light is incident on the light guide where light diffusion is almost uniform.
- the power that can increase the rate V The unevenness of the light emitted from the exit surface of the light guide V is completely taken into account! /.
- the light guide plate disclosed in Japanese Patent Application Laid-Open No. 5-249320 has a complicated structure in which a plurality of plate-like optical waveguide plates are stacked. Therefore, it is possible to obtain a uniform brightness with less attenuation of brightness than in the past. However, there is a problem that the manufacturing cost becomes high.
- the light guide plate of the illumination device disclosed in Japanese Patent Application Laid-Open No. 2002-75036 also has the same problem because the luminance increases in the vicinity immediately above the rod-shaped light source.
- the first problem of the present invention is to solve the above-mentioned problems of the prior art, is thin and lightweight, and has a more uniform and uneven light utilization efficiency (light emission efficiency) from the light emission surface.
- An object of the present invention is to provide a light guide plate capable of emitting illumination light with less and higher luminance.
- Another object of the present invention is to provide a light guide plate that can have a larger light exit surface in addition to the first problem.
- the second problem of the present invention is to solve the above-mentioned problems of the prior art, is thin and lightweight, can be manufactured at a lower cost, and the light utilization efficiency is higher and more uniform.
- a surface that can emit illumination light with less unevenness and higher brightness can be used as a large-sized illumination surface, or can be applied as a backlight to a liquid crystal display device such as a wall-mounted television. It is to provide a state lighting device.
- the third problem of the present invention is to solve the above-mentioned problems of the prior art, is thin and lightweight, can be manufactured at a lower cost, has higher light utilization efficiency, and is more uniform and less uneven. It is another object of the present invention to provide a liquid crystal display device that can perform display with higher brightness, can be a large display screen, or can be a wall-mounted type such as a wall-mounted television. Means for solving the problem
- a first form of the first aspect of the present invention includes a rectangular light emitting surface and a substantially central portion of the rectangular light emitting surface that is substantially parallel to one side thereof.
- a pair of thin end portions formed substantially parallel to the thick portion, and approximately one center of the thick portion on the opposite side of the rectangular light exit surface.
- a parallel groove for accommodating the rod-shaped light source, and the thick-walled portion of the pair of thin-walled end portions on both sides in a direction substantially perpendicular to the one side.
- a transparent light guide plate having a thin thickness and a pair of inclined back surfaces forming a pair of inclined back surfaces on both sides of the parallel grooves, wherein the parallel grooves have a cross-section in the orthogonal direction.
- the interval is narrow and is composed of a pair of contour lines intersecting at the vertices, and each contour line of the parallel grooves in the cross-sectional shape in the orthogonal direction changes in inclination angle with respect to a line perpendicular to the rectangular light exit surface.
- the light guide plate is characterized in that the base end side of the parallel groove farther from the apex has an acute angle than the front end side close to the apex. .
- the light guide plate of the present invention is a bridge type in which the cross-sectional shape of the parallel groove serving as the light incident portion is combined with a curve having a cross section with a larger inclination with respect to the inclination of the curve near the top.
- the light guide plate is characterized in that the cross section of the lower part of the light entrance part is composed of a line segment having the same angle as the angle of the tapered part.
- the intermediate portion of the joint portion between the tapered portion and the parallel groove serving as the light incident portion is parallel to the light emitting surface.
- the tip of the parallel groove is stored in the parallel groove in a first portion corresponding to the parallel groove of the rectangular light exit surface.
- the light source is composed of a pair of contour lines that narrow toward the rectangular light exit surface.
- the pair of inclined rear surface portions are symmetrical with respect to a plane that includes the axis of the rod-shaped light source and is perpendicular to the rectangular light exit surface, and the parallel cross-sectional shape in the orthogonal direction.
- a pair of contour lines of the groove is symmetrical with respect to a center line perpendicular to the rectangular light exit surface of the parallel groove, and a tip portion of the parallel groove has a cross-sectional shape in the orthogonal direction of the parallel groove.
- it is preferable that the distance between the parallel grooves is narrowed symmetrically with respect to a center line perpendicular to the rectangular light exit surface.
- the pair of contour lines at the tip portions of the parallel grooves has a peak value of illuminance (relative illuminance) or luminance (relative luminance) of the first portion of the rectangular light exit surface as the second portion. It is preferable that the interval be narrow so that the average value of illuminance (relative illuminance) or luminance vs. luminance) is 3 times or less.
- the peak value of the illuminance (relative illuminance) or luminance (relative luminance) of the first portion of the rectangular light exit surface is the average value of the illuminance (relative illuminance) or luminance (relative luminance) of the second portion. It is preferable to be less than 2 times.
- each of the pair of inclined rear surface portions has a portion parallel to the rectangular light exit surface in the vicinity of the parallel groove.
- a plurality of minute prisms are formed on at least one of the rectangular light exit surface and the pair of inclined back surface portions.
- a plurality of minute prisms are formed on the pair of inclined back surface portions.
- the prisms formed on the pair of inclined back surface portions have different shapes depending on the positions in the orthogonal direction.
- the prisms formed on the pair of inclined rear surface portions have an asymmetric shape with respect to a surface that is perpendicular to the bottom surface and passes through the apex.
- the prisms formed on the pair of inclined back surface portions have an asymmetric shape with respect to a plane that passes through the apexes and is perpendicular to the inclined back surface portion when there is no prism.
- the prisms formed on the pair of inclined back surface portions are perpendicular to the line connecting the contacts with the adjacent prisms in the cross-sectional shape in the orthogonal direction, and are asymmetrical with respect to the line passing through the apex. It is preferable to have a different shape.
- the prism formed on the pair of inclined back surface portions has a cross-sectional shape in the orthogonal direction. It is preferable that the length of the contour line connecting the apex and the end portion on the parallel groove side and the length of the contour line connecting the apex and the end portion on the thin-walled end side are different.
- the prism formed on the pair of inclined back portions preferably has an apex angle of 70 degrees or more and 140 degrees or less.
- the prism formed on the pair of inclined rear surface portions has an angle between a surface perpendicular to the bottom surface and passing through the apex thereof and the surface on the parallel groove side of 0 degrees or more and 70 degrees or less. It is preferable that the angle force formed by the surface perpendicular to the bottom surface and passing through the apex and the surface on the thin end side is not less than 45 degrees and not more than 70 degrees.
- the prism formed on the pair of inclined rear surface portions has an angle between a surface perpendicular to the bottom surface and passing through the apex thereof and the surface on the parallel groove side of 30 degrees or more and 70 degrees or less. More preferably it is.
- the prisms formed on the pair of inclined back portions preferably have a base length of 0.1 mm or less in the orthogonal direction.
- the tip portion is preferably a portion where an angle formed by the pair of contour lines is within 90 degrees.
- the tip portion is preferably a portion having an angular force of 60 degrees formed by the pair of contour lines.
- the pair of contour lines of at least the tip portion of the parallel groove is formed of two straight lines or a part of a curve that is symmetrical with respect to the center line and has one sharp intersection that intersects each other. Is preferred.
- the two curved forces serving as a pair of contour lines of at least the tip portion of the parallel groove are convex or concave toward the center of the parallel groove.
- the two curves that are the cross-sectional shape of at least the tip portion of the parallel groove can be approximated by a 10th order function, and are convex or concave toward the center of the parallel groove.
- At least one pair of contour lines of the tip portion or the two curves serving as a pair of contour lines of the parallel grooves are a circle, an ellipse, a parabola, or a convex or concave toward the center of the parallel grooves, or Preferably it is part of a hyperbola.
- a cross-sectional shape of at least the tip portion of the parallel groove or a cross-sectional shape of the parallel groove is a triangle.
- the cross-sectional shape of the top portion of the tip portion of the parallel groove is a shape connected by a straight line or a curve symmetrical with respect to the center line before the two symmetrical straight lines or curves intersect with each other. I like it.
- a cross-sectional shape of the top portion of the tip portion of the parallel groove is a shape having a portion parallel to the rectangular light emitting surface in which one sharp intersection is chamfered.
- the cross-sectional shape of at least the tip portion of the parallel groove or the cross-sectional shape of the parallel groove is a triangle, and the cross-sectional shape of the top portion of the tip portion of the parallel groove is relative to the center line.
- a symmetrical trapezoidal shape is preferred.
- a cross-sectional shape of the top portion of the tip portion of the parallel groove is a curved shape that is convex or concave with respect to the rectangular light exit surface and symmetrical with respect to the center line.
- the cross-sectional shape of the top of the tip portion of the parallel groove is a circular shape, an elliptical shape, a parabolic shape, or a hyperbolic shape in which one sharp intersection is rounded symmetrically with respect to the center line. Is preferred.
- At least one pair of contour lines of at least the tip portion of the parallel groove is an ellipse or a part of a hyperbola.
- channel is a sand-slipping surface.
- the rectangular light exit surface has a halftone dot at a portion corresponding to the top portion of the tip portion of the parallel groove.
- the second form of the first aspect of the present invention is a light guide plate according to any one of the first form.
- a light guide plate comprising a plurality of light guide plate blocks as optical plate blocks, the thin end surfaces of which are connected to each other, is provided.
- the inclined rear surfaces of the thin end surfaces of the two light guide plate blocks connected to each other have portions that are gently inclined with respect to each other at the connecting portions.
- both of the light guide plates of the first form and the second form can be made of at least transparent resin. It is preferred to be composed of a material mixed with plasticizer.
- a second aspect of the present invention is a light guide plate according to any one of the first aspect and a rod-like shape accommodated in the parallel groove of the light guide plate.
- the present invention provides a planar lighting device comprising a diffusion sheet disposed on the rectangular light exit surface of a light guide plate.
- a second aspect of the present invention is the above planar illumination device, further comprising a prism sheet disposed between the rectangular light exit surface of the light guide plate and the diffusion sheet. It is preferable to have.
- the ratio of the relative illuminance or relative luminance peak value of the first portion of the rectangular light exit surface of the light guide plate to the average value of the relative illuminance or relative luminance of the second portion is the ratio of the light guide plate It is preferable that the distance is set between the rectangular light exit surface and the diffusion sheet or the thickness allowed for the planar lighting device.
- the third aspect of the present invention includes a backlight unit having the planar illumination device force of any one of the second aspect and the knock light unit.
- the present invention provides a liquid crystal display device comprising: a liquid crystal display panel disposed on the light emission surface side; and a drive unit for driving the backlight unit and the liquid crystal display panel.
- the light guide plate can be made thin and light, and the light use efficiency (light emission efficiency) is higher and more uniform and uneven from the light emission surface. Less and higher brightness illumination light can be emitted.
- the illuminance or brightness of the light emitted from the rod-shaped light source stored in the parallel groove in the first portion of the light emission surface corresponding to the parallel groove is Depending on the ratio of the peak value to the average value of the illuminance or brightness of the other parts, the cross-sectional shape of the parallel groove is narrowed by urging the tip part facing the light exit surface.
- the peak of brightness or brightness can be reduced, and the illuminance or brightness on the light exit surface can be made more uniform
- the luminance distribution can be made more flat and the slope of the cross-sectional shape of the base end portion of the parallel groove is larger than that of the tip portion, for example, by making it steep, so that the light utilization efficiency (light emission efficiency) can be improved.
- the high uniformity and high light emission efficiency required for the light emission surface can be achieved.
- the peak value of illuminance or luminance of the first part of the light exit surface is not more than three times the average value of illuminance or luminance of other parts.
- the illuminance or luminance peak can be reduced by making the cross-sectional shape of the parallel groove narrower toward the tip portion facing the light exit surface, and the illuminance or brightness on the light exit surface can be made uniform.
- the light use efficiency (light emission efficiency) can be further improved.
- a prism sheet in which a plurality of minute prisms are formed on at least one of a rectangular light exit surface and a pair of inclined back surface portions, a prism sheet can be dispensed with when used as a knock light.
- the utilization efficiency of light as a backlight (light emission efficiency) can be improved, the structure of the knocklight can be made compact, and the cost can be reduced.
- the light emitting surface of the light guide plate is made larger by connecting the thin end portions of the light guide plate of the first embodiment to each other. It can be.
- the light guide plate of the first aspect by using the light guide plate of the first aspect, it is thin and lightweight, can be manufactured at a lower cost, and light use efficiency is improved. Higher, more uniform, less uneven, and brighter illumination light can be emitted, the illumination surface can be made large, or it can be applied to a liquid crystal display device such as a wall-mounted television. A planar lighting device that can be provided can be provided.
- planar illumination device of the second aspect by using the planar illumination device of the second aspect, it is thin and lightweight, can be manufactured at a lower cost, and has high light use efficiency.
- Liquid crystal lighting that can display more uniform, less unevenness, and higher brightness, can have a large display screen, or can be wall-mounted such as a wall-mounted TV An apparatus can be provided.
- FIG. 1 is a schematic cross-sectional view of a configuration in which a plurality of light guide plates of the present invention are arranged in parallel.
- FIG. 2A and FIG. 2B are a schematic perspective view and a schematic cross-sectional view, respectively, of a liquid crystal display device using a backlight unit having a light guide plate of the present invention.
- FIG. 3A is a schematic cross-sectional view showing a state in which a prism sheet is disposed between the reflecting sheet and the inclined surface of the light guide plate
- FIG. 3C is a schematic plan view of the prism sheet disposed therebetween as viewed from the light guide plate side
- FIG. 3C is a schematic cross-sectional view of the prism sheet.
- FIG. 4A is a schematic cross-sectional view around a parallel groove of a light guide plate having a hyperbolic cross-sectional shape perpendicular to the length direction of a pair of front end surfaces of the parallel groove
- FIG. 4B is a pair of parallel grooves
- 4C is a schematic cross-sectional view of the periphery of the parallel groove of the light guide plate whose elliptical cross-sectional shape is perpendicular to the length direction of the tip surface
- FIG. 4A is a schematic cross-sectional view around a parallel groove of a light guide plate having a hyperbolic cross-sectional shape perpendicular to the length direction of a pair of front end surfaces of the parallel groove
- FIG. 4B is a pair of parallel grooves
- 4C is a schematic cross-sectional view of the periphery of the parallel groove of the light guide plate whose elliptical cross-sectional shape is perpendicular to the length direction of the tip surface
- FIG. 4C is a cross-section perpendicular to the length direction of a pair of tip surfaces of the parallel groove It is a schematic cross-sectional view around the parallel groove of the light guide plate in which the shape is a partial force of two circular arc curves that are symmetrical with respect to the center line that passes through the center of the parallel groove and is perpendicular to the light exit surface of the light guide plate.
- Figure 4D shows two parabolas whose cross-sectional shape perpendicular to the length direction of a pair of tip surfaces of the parallel groove is symmetrical with respect to the center line passing through the center of the parallel groove and perpendicular to the light exit surface of the light guide plate.
- FIG. 5 is a schematic cross-sectional view around a parallel groove of a light guide plate that is partially formed.
- FIG. 5A shows a parallel structure 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. 5B is a schematic cross-sectional view of the periphery of a groove.
- Fig. 5B shows a combination of a convex curve and a concave curve in which the cross-sectional shape perpendicular to the length direction of a pair of tip surfaces of parallel grooves is directed toward the center of the parallel grooves.
- 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. 6A is a cross-sectional view perpendicular to the length direction of a pair of base end surfaces of a parallel groove, but is formed around a parallel groove of a light guide plate formed by a line segment that is sharper than a pair of front end surfaces.
- FIG. 6B is a schematic cross-sectional view of the parallel groove of the light guide plate in which the cross-sectional shape perpendicular to the length direction of the pair of base end faces of the parallel groove is formed as a concave curve toward the center of the parallel groove. It is a schematic sectional drawing.
- FIG. 7 is a schematic cross-sectional view showing another example of the light guide plate of the present invention.
- FIG. 8 is an example of a halftone dot pattern formed on the light exit surface side of the light guide plate.
- FIG. 9A shows a light guide plate in which the cross-sectional shape of a pair of front end surfaces of parallel grooves is a hypotenuse and the cross-sectional shape of a pair of base end surfaces of parallel grooves is a line segment perpendicular to the light exit surface 9B is a schematic cross-sectional view around the parallel groove of FIG. 9B.
- FIG. 9C is a schematic cross-sectional view of the periphery of the parallel groove of the light guide plate formed by the line segment of FIG. 9C, in FIG. 9C, the cross-sectional shape of the pair of distal end surfaces of the parallel groove is the hypotenuse, and the cross-sectional shape of the pair of base end surfaces of the parallel groove is FIG.
- FIG. 9D is a schematic cross-sectional view of the vicinity of the parallel groove of the light guide plate formed by line segments steeper than the pair of front end surfaces.
- FIG. 9D shows a pair of front end surfaces and a pair of base end surfaces as compared to FIG. 9A.
- FIG. 9E is a schematic cross-sectional view of the periphery of the parallel groove of the light guide plate formed on the parallel portion side, and
- FIG. 9E is a cross-sectional shape of a pair of front end surfaces of the parallel groove, and a pair of base ends of the parallel groove
- the cross-sectional shape of the surface is flat
- FIG. 6 is a schematic cross-sectional view around a parallel groove of a light guide plate formed with a concave curve toward the center of the row groove.
- 10A to 10D are graphs showing the luminance distribution of light emitted from the light exit surface of the light guide plate shown in FIGS. 9A, 9C, 9D, and 9E, respectively.
- FIG. 11A to FIG. 11C are schematic configuration diagrams around the parallel groove of the light guide plate when the parallel surface of the light guide plate shown in FIGS. 9A, 9C, and 9D is not provided.
- 12A to 12C are graphs showing the luminance distribution of light emitted from the light exit surface of the light guide plate shown in FIGS. 11A, 11B, and 11C, respectively.
- FIG. 13A is a graph in which the cross-sectional shape of a pair of front end surfaces of parallel grooves is a hyperbola, and the cross-sectional shape of a pair of base end surfaces of parallel grooves is a line segment perpendicular to the light exit surface.
- FIG. 13B is a schematic cross-sectional view around the parallel groove of the optical plate, and FIG. 13B shows a hyperbola in which the cross-sectional shape of a pair of tip surfaces of the parallel groove is the same as that of a pair of tip surfaces.
- 13C is a schematic cross-sectional view of the periphery of the parallel groove of the light guide plate formed in Fig. 13C. In FIG. FIG. FIG.
- FIG. 13D is a schematic cross-sectional view of the vicinity of the parallel groove of the light guide plate formed by a hyperbola having a steeper slope than the pair of tip surfaces, and FIG. 13D shows a cross-sectional shape of a pair of front end surfaces of the parallel groove is a hyperbola and 1 of the parallel groove.
- FIG. 6 is a schematic cross-sectional view of the periphery of a parallel groove of a light guide plate in which a cross-sectional shape of a pair of base end faces is formed with a concave curve toward the center of the parallel groove.
- FIGS. 14A to 14C show the light of the light guide plate shown in FIGS. 13A, 13C, and 13D, respectively. It is a graph which shows the luminance distribution of the light radiate
- FIG. 15A and FIG. 15B are schematic configuration diagrams around the parallel groove of the light guide plate when the parallel surface of the light guide plate shown in FIGS. 13A and 13C is not provided, respectively.
- FIG. 16A and FIG. 16B are graphs showing the luminance distribution of light emitted from the light emitting surface of the light guide plate shown in FIGS. 15A and 15B, respectively.
- FIG. 17 is a schematic cross-sectional view of another example when the light guide plates of the present invention are arranged in parallel.
- FIG. 18A is a configuration example in which a reflector is arranged on the side surface of the light guide plate of the present invention
- FIG. 18B is a diagram showing a reflector on the side surface of the light guide plate when the light guide plates of the present invention are arranged in parallel.
- This is a configuration example in which
- FIG. 19A is a schematic cross-sectional view showing a state in which a prism is formed on the inclined surface of the light guide plate
- FIG. 19B shows the inclined surface of the light guide plate on which the prism is formed on the light emitting surface side.
- FIG. 2 is a schematic plan view and a schematic cross-sectional view as seen from FIG.
- FIG. 20 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. 21A and FIG. 21B are schematic perspective views of a housing that houses a backlight unit.
- FIG. 22 is a schematic perspective view of a housing in which a backlight unit and a liquid crystal display panel are accommodated.
- FIG. 23 is a schematic cross-sectional view of a housing in which a backlight unit and a liquid crystal display panel are accommodated.
- FIG. 24 is a schematic enlarged cross-sectional view of both end portions of the casing shown in FIG.
- FIG. 25A is a schematic cross-sectional view showing an example of a light source used in the backlight unit of the present invention
- FIG. 25B is a schematic perspective view showing an example of a light source positioning means
- FIG. 25C and FIG. 25D FIG. 26 is a schematic cross-sectional view of the light source shown in FIGS. 25A and 25B.
- FIG. 26A is a schematic sectional view showing another example of the light guide plate of the present invention
- FIG. 26B is a bottom view of the light guide plate shown in FIG. 26A.
- Figure 27A and Figure 27B each integrate a reflective sheet and a light guide plate including a light source.
- 27C is a plan view and a side view schematically showing the configuration, FIG. 27C is a view taken along the CC line in FIG. 27A, and FIG. 27D is a view taken along the DD line in FIG. 27A. It is a figure for demonstrating the structure which integrated the reflection sheet and the light-guide plate containing a light source.
- FIG. 28 is a schematic diagram showing a state in which a halftone dot sheet on which halftone dots are formed is arranged so as to cover the light emission surfaces of a plurality of connected light guide plates.
- FIG. 29A is a configuration example in which a reflecting plate is disposed on the side surface in the longitudinal direction of the light source of the light guide plate of the present invention
- FIG. 29B is a cross-sectional view of FIG. 29A.
- FIG. 30A is a schematic perspective view showing another example of the light guide plate of the present invention
- FIG. 30B is a cross-sectional view taken along the line BB of FIG. 30A
- FIG. 30C is a cross-sectional view of FIG.
- FIG. 30D is a cross-sectional view taken along line C
- FIG. 30D is a cross-sectional view taken along line DD in FIG. 30A.
- FIG. 31A and FIG. 31B are schematic cross-sectional views showing another example of a light guide plate in which a plurality of light guide plates having the same width or light guide plates having different widths are connected.
- FIG. 32 is a schematic cross-sectional view showing an example of a light guide plate having a R-shaped light exit surface.
- FIG. 33A is a schematic cross-sectional view showing an example of a shape in which the end portion of the light guide plate in the longitudinal direction of the light source has an inclination
- FIG. 33B is parallel to the light exit surface and in the longitudinal direction of the light source
- FIG. 33C is a cross-sectional view taken along the line CC in FIG. 33B.
- FIG. 34A is a schematic perspective view showing an example of a light guide plate having a gently curved shape in which the cross-sectional shape in the longitudinal direction of the light source of the light emitting surface is a curve
- FIG. 34B is a light emitting surface shape
- FIG. 5 is a schematic perspective view showing an example of a light guide plate having minute height ribs extending in a direction orthogonal to the longitudinal direction of a light source.
- FIG. 35 is a schematic perspective view of the knock light unit as seen from the back side.
- FIG. 36A is a schematic diagram showing parallel and inclined surfaces of the light guide plate
- FIG. 36B is a schematic diagram showing an enlarged prism engraved on the parallel surface
- FIG. 36C is an inclined diagram
- FIG. 36D to FIG. 36F are schematic views showing other examples of the prisms engraved on the inclined surfaces, respectively.
- FIG. 37A is a schematic diagram showing the parallel surface and the inclined surface of the light guide plate
- FIG. 37B is a schematic diagram showing a prism engraved on the parallel surface
- FIG. 37C is an illustration of the inclined surface.
- FIG. 37D is a schematic diagram showing the prism engraved in the B region of the inclined surface
- FIG. 37E shows the prism engraved in the C region of the inclined surface. It is a schematic diagram.
- FIG. 38 shows another example in which the prisms engraved on the inclined surface of the light guide plate are divided into a plurality of parts in the orthogonal direction and engraved in different shapes according to their positions.
- FIG. 39 is a configuration example in which a halftone dot sheet is disposed on the light exit surface of the light guide plate, and the halftone plate is supported by a convex portion thereon.
- FIG. 40 is a schematic perspective view showing an external appearance of the planar illumination device according to the embodiment of the present invention when viewed from the light exit surface side force.
- FIG. 41A, FIG. 41B, FIG. 41C, and FIG. 41D are a front view, a longitudinal side view, a lateral side view, and a rear view of the planar illumination device shown in FIG.
- FIG. 42 is a partial cross-sectional view of one embodiment of the planar lighting device shown in FIG.
- FIG. 43A is a schematic perspective view of a light guide plate used in the planar illumination device shown in FIG. 3, and FIG. 43B is a cross-sectional shape of one unit light guide plate of the planar illumination device main body shown in FIG. FIG.
- FIG. 44A is a wiring diagram of an embodiment of a linear light source driving device used in the planar illumination device shown in FIG. 2, and FIG. 44B is a wiring diagram of the linear light source driving device shown in FIG. 44A. It is a block diagram.
- FIG. 45 is a schematic configuration diagram showing another embodiment of the planar lighting device of the present invention.
- FIG. 46 is a schematic cross-sectional view of a surface light source device having a conventional light guide plate.
- FIG. 47 is a graph of luminance on the exit surface of the light guide plate of the surface light source device of FIG. 46
- the light guide plate of the present invention the planar illumination device using the same, and the liquid crystal display device
- FIG. 1 is a schematic cross-sectional view of a planar illumination device 2 (hereinafter also referred to as a backlight unit) according to a second aspect of the present invention in which a plurality of light guide plates 18 according to the first aspect of the present invention are configured in parallel. The figure is shown.
- This Such a planar lighting device 2 is used as a knocklight unit of the liquid crystal display device according to the third aspect of the present invention.
- 2A and 2B show a part of one light guide plate 18 of the backlight unit 2 shown in FIG. 1, and a schematic partial perspective view and a schematic partial sectional view of a liquid crystal display device 10 using the backlight unit 2. .
- FIGS. 1 is a schematic cross-sectional view of a planar illumination device 2 (hereinafter also referred to as a backlight unit) according to a second aspect of the present invention in which a plurality of light guide plates 18 according to the first aspect of the present invention are configured in parallel. The figure is shown.
- the liquid crystal display device 10 basically includes 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.
- Drive unit 6 The light guide plate unit 2 includes a cold cathode tube 12, a diffusion sheet 14, prism sheets 16 and 17, a light guide plate 18, a reflector 20, and a reflection plate 22.
- the liquid crystal display panel 4 includes, for example, GH, PC, TN, STN, ECB, PDLC, IPS (In-Plane Switching), VA (Vertic al Aligned) (MVA, PVA, EVA), OCB, ferroelectric liquid crystal, anti-ferroelectric liquid crystal, and other liquid crystal display panels according to the liquid crystal display mode can be used.
- the driving method of the liquid crystal display panel 4 is not particularly limited, and a known driving method such as a simple matrix method or an active matrix method can be used.
- the backlight unit 2 is a planar illumination device for irradiating the entire surface of the liquid crystal display panel 4 with uniform light from behind the liquid crystal display panel 4, and is substantially the same as the image display surface of the liquid crystal display panel 4. It has a light exit surface of a size (light emitting surface).
- the backlight unit 2 basically includes a light source 12, a diffusion sheet 14, two prism sheets 16 and 17, a light guide plate 18, a reflector 20, and a reflection sheet 22.
- the driving method of the backlight unit 2 is not particularly limited.
- the backlight unit 2 may be driven to perform luminance modulation by monitoring the surrounding environment.
- the luminance may be modulated according to the brightness or temperature by providing an ambient light sensor to detect ambient brightness, or providing a temperature sensor to detect ambient temperature.
- the driving method of the knock light unit 2 is not particularly limited.
- R (red), G (green), and B (blue) light sources for example, LED light sources
- It may be driven by a field sequential method in which the liquid crystal display panel 4 is sequentially turned on according to the display, or may be driven by an intermittent lighting method in which light is emitted or turned off sequentially or simultaneously in accordance with the scanning display of the liquid crystal.
- the backlight unit 2 is driven using the field sequential method, R, G Since each color filter of B and B can be removed, the loss of light quantity due to the color filter can be eliminated. If the light source is turned on for a short time according to the intermittent lighting method, it is possible to improve the display performance of moving images.
- FIG. 21A is a schematic perspective view showing the knock light unit 2 from the light emission surface side
- FIG. 21B shows the knock light unit 2 on the back surface side (surface opposite to the light emission surface). It is a schematic perspective view shown.
- the housing 280 has a box-shaped structure with one surface open, and a rectangular opening is formed on the side where the light emission surface of the backlight unit is located.
- Examples of such a housing 280 include a box-shaped structure formed of resin or metal, a frame of a skeleton structure formed of metal, and a box-shaped structure formed of a rigid resin other than metal. Or a frame having a skeletal structure, a case having a rib formed of a metal and a strong resin, and extending in a direction perpendicular to the parallel groove of the light guide plate 18.
- the casing 280 is provided with a catch portion 281 for holding the knock light unit as shown in FIG. 21B.
- the reflection part 22 of the knocklight unit 2 etc. can also be sandwiched by the main part 281.
- FIG. 21A and FIG. 21B show the configuration in which the constituent members constituting the knock light unit 2 are arranged in the housing 280. However, the backlight unit and the liquid crystal display panel are arranged in one housing. A configuration may be used.
- Figures 22 to 24 show configuration examples of the housing that houses the knocklight unit and the liquid crystal display panel. 22 is a schematic perspective view of a housing 290 in which a backlight unit (not shown) and the liquid crystal display panel 4 are housed, and FIG. 23 is a housing in which the backlight unit 2 and a liquid crystal display panel are housed.
- FIG. FIG. 24 is a schematic enlarged cross-sectional view of both end portions of the housing 290 shown in FIG.
- the housing that houses the knocklight unit and the liquid crystal display panel contains the backlight unit in a dedicated housing, and the backlight unit housed in the backlight unit housing.
- the LCD display panel can be accommodated, or the knock light unit main body and the liquid crystal display panel can be fixedly accommodated without accommodating the knock light unit in the backlight unit casing. ,.
- the light source 12 is a rod-shaped cold cathode tube having a small diameter, and is used for illuminating 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 and is connected to the drive boot 6.
- a cold cathode tube is used as the light source 12, but the present invention is not limited to this, and any rod-shaped light source may be used.
- the light source 12 for example, a normal fluorescent tube, a cold cathode tube, a hot cathode tube, an external electrode tube, a light emitting diode (LED), a semiconductor laser, or the like can be used. Alternatively, it is preferable to use a light emitting diode.
- a transparent light guide having a columnar or prismatic shape having a length equivalent to the parallel groove 18f of the light guide plate 18 is used, and an LED light source in which LEDs are arranged on the top and bottom surfaces of the light guide 12 It may be used instead.
- Such an LED light source is capable of emitting LED light from the top and bottom surfaces of the light guide and also emitting LED light with the side force of the light guide.
- an aperture type lamp as shown in FIG. 25A may be used as the light source.
- an aperture type lamp is provided with a high reflectivity member in a portion excluding the angle at which it is desired to be emitted, that is, a high reflectivity member is provided in a portion without emitting light, and a predetermined angle.
- a rod-shaped light source that increases the amount of light emitted from the light source.
- Figure 25C shows a cross section of an aperture type lamp. In FIG. 25C, a region 320 is a light emitting region. The use efficiency of light can be further improved by using an aperture type lamp.
- it is not always necessary to provide a reflection sheet (reflector) disposed on the back side of the light source the apparatus configuration can be simplified, and uneven brightness due to a mounting error of the reflection sheet can be prevented.
- the member having high reflectance various materials such as metal and nonmetal can be used, and it is particularly preferable to use a nonmetal material.
- a non-metallic material As a member having a high reflectance, leakage current can be reduced.
- positioning means at least at one location.
- positioning means for example, as shown in FIG.
- a bent portion 322 is provided in the terminal portion of the lamp, a groove 326 is formed in the support member 324 that supports the lamp, and the bent portion 322 is fitted in the groove 326 of the support member 324 to fix the lamp.
- the angle of the bent portion 322 provided in the terminal portion of the lamp may be any angle as long as it can be defined with respect to the parallel groove of the light guide plate.
- the bent portion 322 is preferably provided so that the light exit region 320 of one type of lamp is divided into two equal parts.
- the shape of the bent portion can be any shape as long as it can fix the arrangement position of the lamp and the arrangement direction of the highly reflective member with respect to the parallel groove and does not hinder the arrangement in the parallel groove. Any shape can be used.
- the positioning means it is possible to easily align the center of the opening of the light source and the center of the parallel groove of the light guide plate, so that light can be efficiently incident on the light guide plate.
- FIG. 26A is a schematic cross-sectional view showing another example of the light guide plate of the present invention
- FIG. 26B is a bottom view of the light guide plate shown in FIG. 26A.
- the light source 12 and the parallel groove 18f formed in the light guide plate 18 are not in direct contact with each other.
- ribs 330 or the like may be partially provided in the parallel groove 18f of the light guide plate 18, and the light source 12 may be disposed in the parallel groove 18 of the light guide plate 18f.
- a rib 330 is formed, for example, in a convex shape having a width of 1 mm or less and a height of about 0.5 mm. Further, it is preferable that the rib 330 is partially provided in the direction of the center line of the parallel groove 18f of the light guide plate.
- an opening is provided on the side surface of the backlight unit corresponding to an extension line in the center line direction of the parallel groove of the light guide plate 18 and the light source 12 can be exchanged through the opening.
- the reflection sheet 22 is made rigid. It is preferable that the reflective sheet 22 and the light guide plate 18 including the light source 12 are integrally formed. At that time, as shown in FIG. 27A to FIG. 27D, either one of the light guide plate 18 and the reflection sheet 22 is provided with a concave portion and the other is provided with a convex portion, or is fixed with a screw.
- the light guide plate 18 and the reflection sheet 22 may be integrated.
- the reflection sheet 22 is formed of a metal material
- the combination of the metal material and the cold cathode tube is used. It is known that stray capacitance occurs.
- the stray capacitance can be reduced by providing an elongated hole in the portion of the reflective sheet that opposes the cold cathode fluorescent lamp.
- a diffusion sheet 14 is for diffusing and uniformizing the light emitted from the light exit surface 18a of the light guide plate 18.
- PET polyethylene terephthalate
- PP polypropylene
- PC polycarbonate
- PMMA polymethylol methacrylate
- MS resin other acrylic resins
- optically transparent resin such as COP (cycloolefin polymer) It is formed by imparting light diffusibility to the member.
- the method is not particularly limited, for example, the surface of the flat plate member is subjected to surface roughening by fine unevenness processing or polishing (hereinafter, the surface on which these are applied is referred to as “sand-rubbed surface”) to improve diffusibility.
- silica pigment such as silica, titanium oxide or zinc oxide, or beads such as rosin glass, zircoure, etc. together with a binder to scatter light on the surface. It is formed by kneading the aforementioned pigments and beads.
- the diffusion sheet 14 may be a mat type or coating type diffusion sheet.
- the diffusion sheet 14 it is also preferable to use a film-like member having a thickness of 500 ⁇ m or less that uses the above-mentioned material and imparts light diffusibility.
- the diffusion sheet 14 is disposed at a predetermined distance from the light exit surface 18a of the light guide plate 18.
- the distance is appropriately determined according to the light amount distribution from the light exit surface 18a of the light guide plate 18. Can change.
- the diffusion sheet 14 is transmitted.
- the brightness of the light that illuminates the liquid crystal display panel 4 can be made more uniform.
- a method of separating the diffusion sheet 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 sheet 14 and the light guide plate 18 can be used.
- the luminance at the light exit surface 18a of the light guide plate 18 corresponding to the parallel groove 18f is determined by the cross-sectional shape of the parallel groove 18f of the light guide plate 18.
- the brightness of the illumination light emitted from the diffusion sheet 14 is partially reduced, and a gap is provided between the diffusion sheet 14 and the light exit surface 18a of the light guide plate 18 to sufficiently reduce the peak value of the light.
- the distribution may be 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 such that the extending directions of the prism rows are perpendicular to each other.
- the prism sheet 16 is disposed so that the apex angle of the prism faces the light exit surface 18a of the light guide plate 18.
- the arrangement order of the prism sheets 16 and 17 is such that a 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, and the prism sheet 16 is disposed on the prism sheet 16.
- the prism sheet 17 having a prism extending in a direction perpendicular to the parallel groove 18f of the light guide plate 18 may be disposed, or vice versa.
- a prism sheet is used, but a sheet in which optical elements similar to prisms are regularly arranged may be used instead of the prism sheet.
- a sheet that regularly includes optical elements such as a lens effect, such as a lenticular lens, a concave lens, a convex lens, and a pyramid type, can be used instead of the prism sheet.
- FIG. 3A is a schematic cross-sectional view showing a state in which the prism sheet 19 is disposed between the reflection sheet 22 and the inclined surface 18d of the light guide plate 18.
- FIG. 3B is an inclined surface of the reflection sheet 22 and the light guide plate 18.
- FIG. 3C is a schematic plan view of the prism sheet 19 disposed between the prism 18 and the light guide plate side force, and
- FIG. 3C is a schematic cross-sectional view of the prism sheet.
- the prism sheet 19 provided between the reflection sheet 22 and the inclined surface 18d of the light guide plate 18 is disposed such that the extending direction of the prism 19a is perpendicular to the parallel groove 18f of the light guide plate 18, and the prism 19a. It is preferable to arrange so that the apex angle of the light guide plate 18 faces the inclined surface 18d of the light guide plate 18.
- An optical element having a lens effect that may be an optical element having the same effect as that of a prism sheet, such as an optical element such as a lenticular lens, a concave lens, a convex lens, or a pyramid type. It is also possible to provide sheets that are regularly arranged.
- the prism sheets 16 and 17, more preferably the prism sheet 19, are used.
- the prism sheet 19 is unnecessary, and either one or both of the prism sheets 16 and 17 may not be used.
- the reflection sheet 22 is for reflecting the light leaking from the back surface (lower surface in the figure) of the light guide plate 18 so as to enter the light guide plate 18 again. Usage efficiency can be improved.
- the reflection sheet 22 is formed so as to cover the lower surface (inclined surface) of the light guide plate 18.
- the reflector 20 is provided behind the light source 12 so as to block the parallel grooves 18f of the light guide plate 18. The reflector 20 reflects light from the lower surface force of the light source 12 and allows the side wall surface light of the parallel groove 18 f of the light guide plate 18 to enter.
- the reflection sheet 22 may be formed of any material as long as it can reflect light leaking from the back surface (the lower surface in the figure) of the light guide plate 18, for example, PET or PP ( Polypropylene) and other fillers are kneaded and then stretched to form voids to increase the reflectivity, and the surface of the transparent or white white resin sheet as described above is mirrored by vapor deposition of aluminum or the like. It can be formed from a formed sheet, a metal foil such as aluminum or a resin sheet carrying a metal foil, or a metal thin plate having sufficient reflectivity on the surface.
- the reflector 20 can be formed of, for example, the same material as that of the reflection sheet 22, that is, a resin material, a metal foil, or a metal plate that imparts sufficient reflectivity to the surface.
- the reflection sheet may be directly attached to a portion excluding the parallel grooves on the surface facing the light exit surface of the light guide plate, for example, an inclined surface.
- the present invention is not limited to directly attaching the reflective sheet to the light guide plate, and a paint having a function equivalent to that of the reflective sheet may be directly applied to the light guide plate.
- the backlight unit in the present invention is not limited to the configuration shown in FIGS. 2A and 2B.
- a brightness enhancement sheet such as a cholesteric polarizing film or a scattering polarizing film can be provided.
- Such a brightness enhancement sheet is preferably disposed between the light guide plate 18 and the liquid crystal display panel 4 (lower polarizing plate) in FIG. 2A and FIG. 2B, particularly in the liquid crystal display panel 4 (lower polarizing plate). It is preferable to place it on the light incident side.
- the reflective polarizing sheet for example, as described in JP-A-6-331824, at least for one polarization plane, the light exit surface of the light guide plate has a refractive index higher than that of the light guide plate.
- a birefringent material having a high refractive index and a refractive index lower than the average refractive index of the light guide plate can be used for the polarization plane orthogonal to the plane of polarization.
- a stretched film as described in JP-A-11-281975 can also be used.
- a stretched film it is preferably attached to one side of the light guide plate via an adhesive layer or an adhesive layer as described in JP-A-11-281975.
- a multilayer structure in which a transparent medium having a relatively high refractive index and a transparent medium having a relatively low refractive index are alternately laminated.
- a transparent medium having a relatively high refractive index and a transparent medium having a relatively low refractive index are alternately laminated.
- a thickness of lOOOnm or less it is also possible to use a film in which at least one dielectric film having a thickness of at least one layer is formed, or a film in which a plurality of types of transparent polymers having different refractive indexes are laminated.
- the transparent support having a substantially W-shaped cross section is provided with at least one dielectric thin film having a thickness equal to or smaller than the visible light wavelength, It is also possible to use a polarization separator that transmits the p-polarized component and reflects at least a part of the s-polarized component for light rays in the vicinity of the predetermined incident direction.
- Japanese Patent Application Laid-Open No. 2004-78234 it has a structure surface that also has a linear arrangement force of prisms with essentially right-angled isosceles coefficients arranged side by side.
- a first material with a surface with a normal modulus forming an angle of approximately 45 ° with respect to the smooth surface opposite the structural surface and a second material essentially the same as the first material, and at least And at least one optical deposit that is on the same plane of the material and also has alternating layer forces of high and low refractive index materials of selected optical thickness.
- the first and second materials are all optically bonded to form a single unit in which the refractive indices of the first and second materials and the multiple layers of the optical deposition are
- the above index of refraction and optical thickness produce selective reflection of polarized light.
- the mixed polarized incident light is separated into s-polarized component and p-polarized component, and the s-polarized component is Reflected by other parts of the optical deposit and reflected parallel to the incident light in that part, but traveling in the opposite direction to the incident light, the p-polarized component is transmitted parallel to the incident light. It is also possible to use a retroreflective polarizer.
- a polarizing filter function and a phase difference are formed on a transparent material in which A-shaped ridges and V-shaped grooves are alternately formed to form a triangular waveform surface.
- a polarizing element provided with a dielectric multilayer film having a plate function can also be used.
- an optical film formed of a polymer having a continuous phase having birefringence and a small amount of a dispersed phase inside the continuous phase. Rum can also be used.
- a polarization separation film having a structure in which a metal thin film using surface plasmon is sandwiched between low refractive index transparent media can be used.
- the polarization direction of the light is changed, for example, orthogonal
- a polarization direction changing film such as a phase film or a diffusion film having a slight birefringence that produces a difference of ⁇ ⁇ 4 in the optical thickness between the polarized components to be integrated with the light guide plate.
- the scattering polarizing film for example, an anisotropic scatterer formed by stretching a composite of a liquid crystal and a polymer as described in JP-A-8-76114 can be used.
- a haze anisotropic layer having a different haze value depending on the vibration direction of linearly polarized light as described in JP-A-2001-343612 may be used.
- fine regions having different material forces are uniformly dispersed in a transparent polymer film, and the polymer film and the micro regions are orthogonal to each other. It is possible to use polarizing elements that have substantially the same refractive index with respect to one of the linearly polarized light and different refractive indexes with respect to the other of the linearly polarized light.
- the molecular helix is oriented so that the axis of the molecular helix extends across the film.
- the pitch force of the film can be changed so that the difference between the maximum pitch and the minimum pitch is at least 1 OOnm.
- a first refractive index substantially equal to or higher than the refractive index of the light guide plate and the light guide plate between the light guide plate and the reflecting member (reflecting plate). It is also possible to dispose an anisotropic layer that has a second refractive index smaller than the refractive index and separates almost all of the first polarization state and the second polarization state force that is perpendicular to the first polarization state. It can improve the brightness.
- the luminance can be improved by forming a rough surface pattern having a polarization separation function on the inclined back surface of the light guide plate. Can do.
- the optical waveguide (light guide plate) is provided with a concave portion filled with a material different from the material of the optical waveguide, and one of these two materials has a refractive index.
- the other material is an anisotropic material with refractive indices no and ne.
- the refractive index no or ne is equal to or substantially equal to np.
- polarized light can be separated at the interface between the isotropic material and the anisotropic material, and most of the light irradiated by the light source is changed to light having the same polarization direction before exiting the optical waveguide. Can do.
- the luminance can also be improved by applying the configuration described in JP-A-10-508151 to the present invention.
- the light guide plate is composed of two or more layers having a light guide function, and at least one of the first layer and the second layer is provided. It is also possible to use a material having birefringence and to provide an interface between the first layer and the second layer and to emit light scattered, refracted or diffracted from the surface of the light guide plate at the interface. Brightness can be improved.
- an optical compensation film for widening the viewing angle can also be provided.
- the optical compensation film for example, an optical compensation film using a discotic liquid crystal or a nematic liquid crystal, an optical compensation film using a collimating film, or the like can be used.
- the optical compensation film is preferably provided by being attached to the upper and lower surfaces of the liquid crystal display panel 4 in FIGS. 2A and 2B.
- optical members having functions such as diffusion, light collection, scattering, and diffraction are shown in FIGS. 2A and 2. It can also be disposed on the light exit side of the light guide plate 18 in B, for example, the light exit surface of the light guide plate 18 or between the light guide plate 18 and the liquid crystal display panel 4. As such an optical component, only one optical component having any one of the above functions may be disposed, or a plurality of optical members having the same or different functions may be disposed in combination. When a plurality of optical components are used in combination, the arrangement order of the plurality of optical components is arbitrary, and the arrangement order can be appropriately adjusted according to the desired optical characteristics.
- optical members such as the diffusion film, the prism sheet, and the brightness enhancement sheet described above may be used one by one or plural. Further, such optical members can be used by being attached to each other. It can also be attached directly to the light guide plate, or it can be attached to the light incident side of the liquid crystal display panel. Also, the arrangement of the prism sheet is not particularly limited. For example, when the light emission direction is upward, the prism may be disposed upward! Or may be disposed downward. Use it by stacking sheets.
- the optical component such as the diffusion sheet 14 and the prism sheets 16 and 17 is arranged between the light guide plate 18 and the liquid crystal display panel 4.
- the configuration of the optical component is not limited to such a configuration example, and can be configured as shown below, for example.
- a diffusion sheet in which halftone dots for suppressing the generation of bright lines are formed by printing, a prism sheet, and the brightness enhancement sheet described above are arranged in order. can do.
- the prism sheet in which the halftone dots are preferably formed on the light incident side surface of the diffusion sheet, that is, the surface facing the light emitting surface of the light guide plate, has a prism row arranged on the light emitting side. It is preferable.
- a configuration may be adopted in which a diffusion sheet in which halftone dots are formed by printing and a brightness enhancement sheet are arranged on the light exit surface side of the light guide plate.
- a halftone dot is formed on the light incident side surface of the diffusion sheet.
- a halftone dot is formed on the light exit surface of the light guide plate by printing, and a diffusion sheet and a brightness enhancement sheet are arranged in this order on the light exit surface side of the light guide plate. You can also.
- a halftone dot is formed on the light exit surface of the light guide plate, a diffusion sheet is used without forming a halftone dot.
- a halftone dot is formed on the light exit surface of the light guide plate by printing, and on the light exit surface side of the light guide plate, two diffusion sheets having the same or different characteristics, and one brightness enhancement sheet are provided. It is also possible to adopt a configuration in which the are sequentially arranged. Further, a configuration may be adopted in which two diffusion sheets and one brightness enhancement sheet are sequentially arranged on the light exit surface side of the light guide plate. In this case, halftone dots are not formed on the light exit surface of the light guide plate, but halftone dots are formed by printing on the surface of the diffusion sheet located on the side close to the light guide plate and facing the light exit surface of the light guide plate.
- a halftone dot is formed on the light exit surface of the light guide plate by printing, and the light exit surface side of the light guide plate is formed.
- a configuration in which the diffusion sheet and the brightness enhancement sheet are arranged in this order is preferable.
- a light guide plate 18 includes a rectangular light exit surface 18a, a thick portion 18b parallel to one side thereof, and a pair of sides formed on both sides of the thick portion 18b in parallel to the one side.
- a pair of inclined rear surface portions 18e that form a slanted surface 18d by thinning the thin end portions 18c and urging the thin end portions 18c on both sides in a direction perpendicular to the one side from the thick portion 18b.
- the thick portion 18b has a parallel groove 18f for accommodating the light source 12 formed parallel to the one side.
- the light guide plate 18 is a flat plate having a rectangular outer shape on the surface, and is formed of a transparent resin.
- the light guide plate 18 is flat on one side to form a light emission surface 18a, and the other surface is thinned toward the one side from the thick portion 18b toward the both sides.
- a pair of inclined surfaces 18d are formed to be inclined with respect to one surface.
- the inclined surface 18d is formed as a flat surface, but it may be a curved surface.
- a parallel surface 18g parallel to the light exit surface 18a is formed between the inclined surface 18d and the base end surface 18i. That is, the thick portion 18b of the light guide plate 18 is provided with a parallel surface 18g extending from the inclined surface 18d.
- 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 film).
- Transparent resins such as phthalate), PP (polypropylene), PC (polycarbonate), PMMA (polymethylol methacrylate), benzyl methacrylate and MS resin, other acrylic resins, or COP (cycloolefin polymer) Can be used.
- the transparent resin may be mixed with fine particles for scattering light. Thereby, the light emission efficiency from the light emission surface 18a can be further increased. When fine particles for scattering light are mixed in the transparent resin, the fine particles may be isotropic or anisotropic.
- a color tone correction agent may be provided to correct the color tone of light incident on the liquid crystal display panel.
- a light guide plate mixed with a color tone correction agent and a color correction filter for correcting the color tone can be used in combination.
- the color temperature of the light emission surface of the liquid crystal display panel is lower than the color temperature of the light source due to the spectral characteristics of the transmission member. Therefore, it is necessary to set the color temperature of the light source higher. However, if the color temperature of the light source is set high, the luminance efficiency may decrease.
- a transparent material that easily transmits blue as the transparent member used for the light guide plate, the color temperature of the light source and the color temperature of the liquid crystal display surface can be made equal.
- liquid crystal display panel power with high brightness emitted from the light source without lowering the color temperature.
- the power consumption can be further reduced, the light source can have a longer life, and the number of light sources and the number of inverters can be reduced to reduce the cost.
- the light guide plate of the present invention may be produced by mixing a plasticizer into the transparent resin.
- the light guide plate can be made flexible, that is, a flexible light guide plate. It becomes possible to change to the shape. Therefore, the surface of the light guide plate can be formed into various curved surfaces. As a result, for example, when a light guide plate or a planar lighting device using this light guide plate is used as a display plate related to illumination, it can be attached to a wall having a curvature.
- the light plate can be used for more kinds, wider range of illumination, POP (POP advertising), etc.
- phthalate ester specifically, dimethyl phthalate (DMP), jetyl phthalate (DEP), dibutyl phthalate (DBP), di-2-ethylhexyl phthalate ( DOP (DEHP)), di-normaloctyl phthalate (DnOP), diisanol phthalate (DINP), dianol phthalate (DNP), diisodezyl phthalate (DIDP), phthalate mixed ester (C to C ) (610P, 71 IP, etc.), butyl benzyl phthalate (BBP)
- dioctyl adipate DOA
- diisonol adipate DINA
- di-normal alkyl adipate C 610A
- adipine DOTA
- DBS dioctyl sebacate
- DOS dioctyl sebacate
- TCP tricresyl phosphate
- ATBC tributyl acetyl citrate
- ESBO epoxidized soybean oil
- TOTM trioctyl trimellitic acid
- 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 preferably determined so that a part of the light source 12 does not protrude from the lower surface of the light guide plate 18.
- the mechanical strength of the light guide plate 18, and changes over time 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 utilization efficiency from the light source 12 accommodated in the parallel groove 18f. It is preferable to form in the longitudinal direction.
- the parallel groove 18f is formed of a pair of distal end surfaces 18h constituting the distal end portion and a pair of proximal end surfaces 18i constituting the proximal end portion, and the distal end surface 18h with respect to the light emitting surface 18a.
- the slope of the base end face 18i is steeper than the slope of. That is, the maximum value of the angle formed by the tangent plane of the tip end surface 18h and the light exit surface 18a, that is, the angle (inclination angle) ⁇ n formed by the tangent plane of the base end surface 18i and the light exit surface 18a from the maximum tilt angle Is big.
- the light guide plate 18 having the structure shown in FIG.
- the side force that forms the parallel groove 18f is incident on the inside of the light guide plate 18.
- the reflected light is reflected by the inclined surface 18d of the light guide plate 18 and then emitted from the light exit surface 18a.
- the force that a part of light leaks from the lower surface of the light guide plate 18, the leaked light is reflected by the reflection sheet 22 formed on the inclined surface 18 d side of the light guide plate 18 and again enters the light guide plate 18.
- Incident light is emitted from the light exit surface 18a. In this way, uniform light is emitted from the light exit surface 18a of the light guide plate 18.
- the inclined surface 18d of the inclined surface 18d is made to effectively reach the light beam in a direction perpendicular to the light exit surface 18a and in a parallel direction (depth direction).
- the angle (taper) is limited. That is, the angle (taper) of the inclined surface 18d is set 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 thereof forming a triangle, the base end portion thereof forming a rectangle, and the whole.
- it is formed to have a convex home base shape on the light exit surface 18a side. Therefore, the pair of front end surfaces 18h of the parallel grooves 18f are inclined at a predetermined angle with respect to a vertical plane perpendicular to the light exit surface 18a and passing through the center of the light source, with one end of each pair intersecting each other.
- the cross-sectional shape is formed by two line segments (slopes) with a predetermined angle of inclination forming one vertex of the triangle!
- a pair of base end faces 18i of the parallel grooves 18f of the light guide plate 18 are connected to the other ends of the pair of tip end faces 18h, and are parallel and symmetrical with respect to the vertical plane.
- 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 cross-sectional shape of the parallel groove 18f is a home base shape in which the tip end portion is triangular and the base end portion is rectangular.
- the present invention is not limited to this, and the tip end portion is not limited thereto. Any shape may be used as long as the slopes intersect with each other and the slope of the base end connected to the tip is steeper than the slope of the tip. That is, the cross-sectional shape of the parallel groove 18f is directed toward the light exit surface 18a at the tip portion, and the distance between the parallel grooves 18f is reduced, and a pair of contours intersect at the apex.
- Each contour line has a part where the angle of inclination with respect to the line perpendicular to the light exit surface 18a changes, and the base end side of the parallel groove farther from the apex side than the apex side (tip surface 18h) closer to the apex Any shape may be used as long as the base end surface 18i has an acute angle.
- the contour line on the tip side (tip surface 18h) near the apex is farther from the apex than the inclination angle (maximum inclination angle ⁇ ) formed by 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 base end side (base end face 18i) with the light exit surface 18a is larger.
- the pair of tip surfaces 40 of the parallel grooves 18f can be formed into a hyperbola shape, and as shown in FIG. 4B, the pair of tip surfaces 42 of the parallel grooves 18f can be formed into an ellipse 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. In the present invention, even if the cross-sectional shape of the parallel groove of the light guide plate is any of the above shapes, uniform light can be emitted from the light exit surface of the light guide plate.
- FIG. 4C shows a cross-sectional shape force of a pair of front end surfaces 50 of the parallel groove, and a center line perpendicular to the light exit surface of the light guide plate through the center of the parallel groove 18f having one sharp intersection intersecting each other.
- An example of the partial force of two curves symmetric with respect to is shown.
- the light guide plate 18 shown in FIG. 4C has two symmetrical curves 51a and 51b that form a pair of front end surfaces 50 with respect to a center line X that passes through the center of the parallel groove 18f and is perpendicular to the light exit surface 18a of the light guide plate 18. 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 has a sharp shape as shown in FIG. 4C.
- the cross-sectional shape of the pair of front end surfaces 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.
- Figure 4D The optical plate 18 is a case where two symmetrical curves 54a and 54b, which are a pair of tip surfaces 53 with respect to the center line X perpendicular to the light exit surface 18a of the light guide plate 18 through the center of the parallel groove 18f, are parabolas. is there.
- a pair of tip surfaces 53 of the parallel groove 18f are formed 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. Is done.
- FIGS. 1 to 4D in the cross-sectional shape of the parallel grooves, the curves forming the pair of tip surfaces of the parallel grooves are directed toward the center of the parallel grooves.
- FIG. 5A and FIG. 5B show another embodiment of the light guide plate of the present invention different from FIG.
- FIG. 5A is an example of a light guide plate in which the cross-sectional shape of the pair of front end surfaces 60 of the parallel groove 18f is formed by two curves 61a and 61b that are convex toward the center of the parallel groove 18f, and FIG.
- the cross-sectional shape of the pair of tip faces 63 of the parallel groove 18f is a combination of convex curves 64a and 64b that are convex toward the center of the parallel groove 18f and concave curves 66a and 66b that are directed toward the center of the parallel groove 18f.
- Curved force is an example of a light guide plate to be formed.
- the light guide plate having the parallel grooves having the cross-sectional shape as shown in FIGS. 5A and 5B can also emit light with sufficient light emission surface force 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 emitting surface 18a in contact with the front end surface 18h and the parallel surface 18g.
- Force as a symmetric vertical line 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 (see Fig. 2)
- the cross-sectional shape of the pair of base end surfaces 70 of the parallel grooves is shown in Fig. 6A.
- the angle formed by the line perpendicular to the light exit surface 18a and passing through the center of the light source has an inclination of a predetermined angle that is sharper than the tip surface 18h.
- each base end face of the parallel groove is not limited to a straight line, and a curved line can be used, and as shown in FIG. 6B, the cross-sectional shape of the pair of base end faces 72 of the parallel groove 18f is the same as that of the parallel groove 18f. It is good also as a concave curve which is directed to the center.
- various curves used for a pair of tip surfaces of the parallel groove such as a hyperbola shape, an ellipse shape, and a parabola shape, can be used.
- the shape of the parallel grooves is not limited to this, and may 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 of the parallel groove and a pair of proximal end surfaces, a joint between the pair of proximal end surfaces of the parallel grooves and the parallel surface, and a parallel surface and an inclined surface
- the seam should have a smooth shape with R> 0.01 [mm].
- the smooth shape of the seam can prevent diffuse reflection of light at the seam, and can prevent generation of bright lines and uneven brightness.
- 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, the light exit surface and the ridges are parallel to the axis of the rod-shaped light source and the inclined surface. It is preferable to form a plurality of minute prisms having a predetermined shape.
- a planar illumination device such as a knocklight is formed by forming a large number of micro 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).
- the prism sheet can be eliminated, the light use efficiency as the planar lighting 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 small 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. I like it.
- the apex angle 0 shall be 100 ° ⁇ ⁇ ⁇ 140 °
- the prism formed on the light exit surface has an apex angle 0 of 40 ° ⁇ ⁇ ⁇ 70 °.
- 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 is not necessarily provided As shown in FIG. 7, it is possible to adopt a structure in which the inclined surface 80 and the base end surface 18i of the parallel groove 18f are directly connected without providing a parallel surface.
- the density of halftone dots is high at a certain center line X and gradually increases from the center line X toward both sides (perpendicular to the center line).
- a halftone dot pattern 92 that lowers the density of halftone dots may be formed on the light exit surface 18a of the light guide plate 18, for example, by printing.
- 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 in the deepest part or 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 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, it is possible to increase the brightness by lengthening the deepest flat end portion of the parallel groove.
- the length of the flat end portion is preferably 20% or less of the diameter of the cold cathode tube, and more preferably 10% or less.
- 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 peak value of illuminance or luminance may be reduced by making the top part (deepest part) of the tip part of the parallel groove a sand rubbing surface.
- the average value of the luminance formed in the light exit surface 18a of the light guide plate 18 other than the parallel grooves 18f that is, the portion corresponding to the inclined surface 18d (second portion).
- the parallel groove of the light guide plate 18 The tip shape of the tip of 18f 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.
- this ratio is preferably 3 or less, more preferably 2 or less.
- 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, the thickness of the knock light unit 2 (the light emission of the light guide plate 18) The distance between the exit surface 18a and the diffusion sheet 14) can be somewhat thicker (or larger), the diffusion sheet 14 used in the knocklight unit 2 can have a higher diffusion efficiency, and the number of sheets used can be increased.
- the illumination light emitted from the light exit surface 18a of the light guide plate 18 can be sufficiently diffused (such as mixing).
- the force that leads to high cost The ratio of the luminance peak value of the first part of the light exit surface 18a of the light guide plate 18 to the average value of the brightness of the second part of the light exit surface 18a of the light guide plate 18 Can be set large. However, if this is not the case, it is necessary to set the value of this ratio small.
- the peak luminance value of the first portion of the light exit surface 18a of the light guide plate 18 is the average value of the brightness of the second portion of the light exit surface 18a of the light guide plate 18.
- the tip shape of the parallel groove 18f of the light guide plate 18 is tapered so as to be 3 times or less, more preferably 2 times or less.
- the peak value force of the luminance of the first part of the light exit surface 18a of the light guide plate 18 is set to be not more than three times the average value of the brightness of the second part of the light exit surface 18a of the light guide plate 18.
- the tip portion of the parallel groove 18f that tapers down also causes the central force of the rod-shaped light source 12 to be directed to the light exit surface 18a.
- the angle with respect to the line (X) is a portion that is within 90 degrees on both sides, more preferably, a portion that is within 60 degrees. That is, in the present invention, in order to reduce the luminance peak value of the first portion corresponding to the parallel groove 18f of the light exit surface 18a of the light guide plate 18, the portion to be tapered of the parallel groove 18f is the portion of the parallel groove 18f.
- the entire tip may be used, but 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 set so that the distance from the light exit surface increases. It consists of a pair of contour lines that become narrower and intersect at the vertices, and each contour line has a portion whose inclination angle changes with respect to a line perpendicular to the light exit surface. ) From the shape farther away from the apex, the base end side of the parallel groove (a pair of base end faces) has a sharper angle, which can further reduce brightness unevenness and improve the output efficiency. .
- the cross-sectional shape of the parallel groove is a combination of curves having other inclination angles ⁇ (> ⁇ ) with respect to the maximum inclination angle ⁇ m of other hyperbola, parabola, and other curved line segments.
- the luminance distribution of light emitted from the light exit surface of the light guide plate was examined by simulation.
- the parallel groove 18f of the light guide plate 18 shown in FIG. 9B has an inclination of a predetermined angle with respect to a line passing through the center of the light source 12 perpendicular to the cross-sectional shape light emission surface 18a of the tip surface 18h.
- the cross-sectional shape of the base end face 18i is formed by a line segment that is in contact with the front end face 18h and the parallel face 18g and is perpendicular to the light exit surface 18a, and the top is formed by a curved shape.
- the parallel surface 18g is an intersection of a line obtained by extending the line segment of the front end surface 18h of the parallel groove 18 and a line parallel to the light exit surface and passing through the lower end of the light guide plate, and a pair of bases of the parallel groove. It is provided between the lower ends of the end faces.
- the light guide plate 18 shown in FIG. 9A has a diameter of the light source 12 of 3 mm, a tilt angle of the tip surface 18h with respect to a line perpendicular to the light exit surface 18a and passing through the center of the light source 12, and a curved surface at the top.
- the luminance distribution of light emitted from the light exit surface 18a was also examined for the light guide plate 18 whose parallel groove 18f shown in FIG. 9B has a substantially triangular cross-sectional shape.
- the cross-sectional shape of the side surface 74 of the parallel groove 18f is a shape formed only by the hypotenuse, It has the same shape as the light guide plate shown in FIG. 9A.
- FIG. 10A shows the luminance distribution on the light exit side surface of the light guide plate shown in FIG. 9A and the light guide plate shown in FIG. 9B.
- the vertical axis represents luminance [cdZm 2 ] and the horizontal axis represents the light guide. Indicates the distance [mm] from the center of the plate (the center of the parallel groove).
- the luminance distribution on the light exit surface of the light guide plate shown in FIG. 9A is indicated by a solid line
- the brightness distribution on the light exit surface of the light guide plate having the shape shown in FIG. 9B is indicated by a dotted line.
- the difference between the maximum luminance value and the minimum luminance value on the light exit surface of the light guide plate shown in FIG. 9A is the difference between the maximum brightness value on the light exit surface of the light guide plate shown in FIG. 9B. Less than the difference between the minimum values. That is, the light guide plate shown in FIG. 9A can emit light with reduced brightness unevenness compared to the light guide plate shown in FIG. 9B. That is, the luminance on the light exit surface can be made more uniform.
- the output efficiency of the light guide plate having the shape shown in FIG. 9A is 65.4%, and the output efficiency of the light guide plate having the shape shown in FIG. It was 7%.
- the incident efficiency of the light guide plate having the shape shown in FIG. 9A was 84.0%, and the incident efficiency of the light guide plate having the shape shown in FIG. 9B was 95.5%. In this way, the light guide plate shown in FIG. 9A can have higher emission efficiency and incidence efficiency than the light guide plate shown in FIG. 9B.
- a pair of base end faces 70 of parallel grooves are half of the inclination of the front end face 18h, that is, with respect to the light exit face 18a.
- the light exit surface of the light guide plate having the same shape as the light guide plate in FIG. 9A, except that the line segment has a 15-degree slope with respect to the line that passes through the center of the light source (the hypotenuse). The luminance distribution of the light emitted from the light source was examined.
- FIG. 10B shows the luminance distribution on the light exit side surface of the light guide plate shown in FIG. 9C.
- the vertical axis indicates the luminance [cdZm 2 ]
- the horizontal axis indicates the distance [mm] from the center of the light guide plate (the central portion of the parallel groove).
- the luminance distribution on the light exit surface of the light guide plate shown in FIG. 9C is shown by a solid line
- the brightness distribution on the light exit surface of the light guide plate having the shape shown in FIG. 9B is shown by a dotted line.
- the difference between the maximum value and the minimum value on the light exit surface of the light guide plate shown in FIG. 9C is the difference between the maximum value on the light exit surface of the light guide plate shown in FIG. Less than the difference between the minimum values. That is, the light guide plate shown in FIG. 9C can emit light with reduced brightness unevenness compared to the light guide plate shown in FIG. 9B. In other words, the brightness on the light exit surface It can be made uniform.
- the output efficiency of the light guide plate having the shape shown in FIG. 9C was 61.9%. In this way, the light guide plate shown in FIG. 9C can have higher emission efficiency than the light guide plate shown in FIG. 9B.
- the connecting portion between the distal end surface 18 and the base end surface 18i 'of the parallel groove 18f is more than the light guide plate shown in Fig. 9A.
- the light intensity distribution of the light exiting surface of the light guide plate having the same shape as the light guide plate of FIG.
- FIG. 10C shows the luminance distribution on the light exit side surface of the light guide plate shown in FIG. 9D.
- the vertical axis indicates the luminance [cdZm 2 ]
- the horizontal axis indicates the distance [mm] from the center of the light guide plate (the central portion of the parallel groove).
- the luminance distribution on the light exit surface of the light guide plate shown in FIG. 9D is shown by a solid line
- the brightness distribution on the light exit surface of the light guide plate having the shape shown in FIG. 9B is shown by a dotted line.
- the difference between the maximum value and the minimum value on the light exit surface of the light guide plate shown in FIG. 9D is the difference between the maximum value on the light exit surface of the light guide plate shown in FIG. It is almost the same as the difference between the minimum values. That is, the light guide plate shown in FIG. 9D can emit light with reduced luminance unevenness equivalent to the light guide plate shown in FIG. 9B.
- the output efficiency of the light guide plate having the shape shown in FIG. 9D was 61.5%. In this way, the light guide plate shown in FIG. 9D can have higher emission efficiency than the light guide plate shown in FIG. 9B.
- the cross-sectional shape of the pair of base end surfaces 72 of the parallel groove 18f shown in FIG. 9E is a concave curve directed toward the center of the parallel groove 18f. Except for this, the luminance distribution of light emitted from the light exit surface of the light guide plate having the same shape as that of FIG. 9A was examined.
- FIG. 10D shows the luminance distribution on the light exit side surface of the light guide plate shown in FIG. 9E.
- the vertical axis indicates the luminance [cdZm 2 ]
- the horizontal axis indicates the distance [mm] from the center of the light guide plate (the central portion of the parallel groove).
- the luminance distribution on the light exit surface of the light guide plate shown in FIG. 9E is shown by a solid line
- the brightness distribution on the light exit surface of the light guide plate having the shape shown in FIG. 9B is shown for comparison. Is indicated by a dotted line.
- the difference between the maximum value and the minimum value on the light exit surface of the light guide plate shown in FIG. 9E is the difference between the maximum value on the light exit surface of the light guide plate shown in FIG. 9B. Less than the difference between the minimum values. That is, the light guide plate shown in FIG. 9E can emit light with reduced brightness unevenness compared to the light guide plate shown in FIG. 9B. That is, the luminance on the light exit surface can be made more uniform.
- the emission efficiency of the light guide plate having the shape shown in FIG. 9E was 70.9%. In this way, the light guide plate shown in FIG. 9E can have higher emission efficiency than the light guide plate shown in FIG. 9B.
- the parallel grooves of the light guide plate are formed in the shape of the present invention, so that the shape of the parallel grooves is the same as that of a triangle that can reduce the luminance unevenness as compared with the conventional case. Therefore, it is possible to reduce the luminance unevenness or the luminance unevenness and improve the emission efficiency.
- the light guide plate shown in FIG. 11A is not provided with a parallel surface, except that the inclination angle of the inclined surface 80 is changed and the base end face 18i of the parallel groove 18f and the inclined surface 80 are directly connected. It has the same shape as the light guide plate shown in 9A.
- the light guide plate shown in FIG. 11B and FIG. 11C also does not provide a parallel surface, changes the inclination angle of the inclined surface 80, and directly connects the pair of base end surfaces 70 or 18i 'of the parallel groove 18f and the inclined surface 80. Except this, it has the same shape as the light guide plate shown in FIGS. 9C and 9D.
- FIGS. 12A to 12C show the luminance distributions on the light exit side surfaces of the light guide plates shown in FIGS. 11A to 11C, respectively.
- the vertical axis represents luminance [cd / m 2 ]
- the horizontal axis represents the distance [mm] from the light guide plate center (the central portion of the parallel groove).
- 12A to 12C show the luminance distribution on the light exit surface of the light guide plate shown in FIGS. 11A to 11C by solid lines, respectively, and for comparison, the luminance component on the light exit surface of the light guide plate having the shape shown in FIG. 9B.
- the cloth is indicated by a dotted line.
- the luminance unevenness can be equal to or reduced with the light guide plate shown in FIG. 9B in any light guide plate.
- the output efficiency of the light guide plate shown in FIG.11A is 61.5%
- the output efficiency of the light guide plate shown in FIG.11B is 61.6%
- the emission efficiency of the light guide plate shown in FIG. 11C was 62.0%.
- any light guide plate can improve the emission efficiency over the light guide plate shown in FIG. 9B.
- the shape of the parallel groove is a triangular shape that can reduce the luminance unevenness as compared with the conventional case. Alternatively, it is possible to further reduce luminance unevenness and improve the emission efficiency.
- the light guide plate 18 shown in FIG. 13A has the same shape as the light guide plate shown in FIG. 9A, except that the cross-sectional shape of the pair of tip surfaces 40 of the parallel grooves 18f is a hyperbola.
- the luminance distribution of light emitted from the light exit surface 18a was also examined for the light guide plate 18 in which the cross-sectional shape of the side surface 78 of the parallel groove 18f shown in FIG.
- the light guide plate shown in FIG. 13B is shown in FIG. 13A except that one side surface 78 of the parallel groove 18f, that is, the cross-sectional shape of the front end surface and the base end surface is formed by one hyperbola. It has the same shape as the light guide plate.
- FIG. 14A shows the luminance distribution on the light exit side surface of the light guide plate shown in FIG. 13A and the light guide plate shown in FIG. 13B.
- the vertical axis represents luminance [cdZm 2 ]
- the horizontal axis represents the distance [mm] from the center of the light guide plate (the central portion of the parallel groove).
- the luminance distribution on the light exit surface of the light guide plate shown in FIG. 13A is indicated by a solid line
- the brightness distribution on the light exit surface of the light guide plate having the shape shown in FIG. 13B is indicated by a dotted line.
- the difference between the maximum value and the minimum value of the luminance on the light exit surface of the light guide plate shown in FIG. 13A is the maximum value of the brightness on the light exit surface of the light guide plate shown in FIG. 13B. Less than the difference between the minimum values. That is, the light guide plate shown in FIG. 13A can emit light with less uneven brightness than the light guide plate shown in FIG. 13B. That is, the brightness at the light exit surface Can be made more uniform.
- the output efficiency of the light guide plate having the shape shown in FIG. 13A is 63.1%, and the output efficiency of the light guide plate having the shape shown in FIG. 56. 6%.
- the light guide plate shown in FIG. 13A can have higher emission efficiency than the light guide plate shown in FIG. 13B.
- the cross-sectional shape of the pair of base end faces 76 of the parallel grooves 18f is a hyperbola having a half inclination of the hyperbola of the front end face 40.
- the light guide plate of FIG. 13A except that the angle formed by the line perpendicular to the light exit surface 18a and passing through the center of the light source is smaller than the hyperbola of the tip surface 40 and is a hyperbola.
- the brightness distribution of the light emitted from the light exit surface of the light guide plate having the same shape as in Fig. 1 was examined.
- FIG. 14B shows the luminance distribution on the light exit side surface of the light guide plate shown in FIG. 13C.
- the vertical axis represents the luminance [cdZm 2 ]
- the horizontal axis represents the distance [mm] from the center of the light guide plate (the central portion of the parallel groove).
- the luminance distribution on the light exit surface of the light guide plate shown in FIG. 13C is shown by a solid line
- the brightness distribution on the light exit surface of the light guide plate having the shape shown in FIG. 13B is shown by a dotted line for comparison.
- the difference between the minimum values is almost the same. That is, the light guide plate shown in FIG. 13C can emit light with reduced luminance unevenness equivalent to the light guide plate shown in FIG. 13B.
- the output efficiency of the shaped light guide plate shown in FIG. 13C was 59.1%. In this way, the light guide plate shown in FIG. 13C can have higher emission efficiency than the light guide plate shown in FIG. 13B.
- the cross-sectional shape of the pair of base end surfaces of the parallel grooves is a concave curve toward the center of the parallel grooves. Except for this, the brightness distribution of the light emitted from the light exit surface of the light guide plate having the same shape as the light guide plate in FIG. 13A was examined.
- FIG. 14C shows the luminance distribution on the light exit side surface of the light guide plate shown in FIG. 13D.
- the vertical axis represents luminance [cdZm 2 ]
- the horizontal axis represents the center of the light guide plate (the center of the parallel groove). Indicates the distance [mm] from minutes).
- the luminance distribution on the light exit surface of the light guide plate shown in FIG. 13D is shown by a solid line
- the brightness distribution on the light exit surface of the light guide plate having the shape shown in FIG. 13B is shown by a dotted line for comparison.
- the difference between the maximum value and the minimum value on the light exit surface of the light guide plate shown in FIG. 13D is the difference between the maximum value on the light exit surface of the light guide plate shown in FIG. Less than the difference between the minimum values. That is, the light guide plate shown in FIG. 13D can emit light with less uneven brightness than the light guide plate shown in FIG. 13B. That is, the luminance on the light exit surface can be made more uniform.
- the output efficiency of the light guide plate having the shape shown in FIG. 13D was 67.8%.
- the light guide plate shown in FIG. 13D can have higher emission efficiency than the light guide plate shown in FIG. 13B.
- the shape of the parallel groove is a hyperbolic shape that can reduce the luminance unevenness as compared with the conventional case. Alternatively, it is possible to further reduce luminance unevenness and improve the emission efficiency.
- the pair of base end surfaces of the parallel grooves and the inclined surfaces are directly connected to each other, and light is emitted from the light exit surfaces of the light guide plates having various shapes without providing parallel surfaces.
- the brightness distribution of light was examined.
- the light guide plate shown in FIG. 15A is not provided with a parallel surface, but the angle of inclination of the inclined surface is changed and the pair of base end surfaces of the parallel groove and the inclined surface are directly connected, respectively. It has the same shape as the light guide plate shown in 13A.
- the light guide plate shown in FIG. 15B is also provided in FIG. 13C except that a parallel surface is not provided, the inclination angle of the inclined surface is changed, and the pair of base end surfaces of the parallel groove and the inclined surface are directly connected to each other.
- the shape is the same as the illustrated light guide plate.
- FIG. 16A and FIG. 16B show the luminance distribution on the light exit side surface of the light guide plate shown in FIGS. 15A and 15B, respectively.
- the vertical axis represents the luminance [cdZ m 2 ]
- the horizontal axis represents the distance [mm] from the center of the light guide plate (the central portion of the parallel groove).
- 16A and 16B show the luminance distribution on the light exit surface of the light guide plate shown in FIGS. 15A and 15B by solid lines, respectively.
- the light of the light guide plate having the shape shown in FIG. 13B is shown.
- the luminance distribution on the exit surface is indicated by a dotted line.
- FIG. 16A and FIG. 16B show that the luminance unevenness can be equal to or less than that of the light guide plate shown in FIG. 13B in any of the light guide plates shown in FIG. 16A and FIG. 16B.
- the output efficiency of the light guide plate shown in FIG.15A is 63.9%
- the output efficiency of the light guide plate shown in FIG.15B is 58.9%. there were.
- any light guide plate can improve the emission efficiency over the light guide plate shown in FIG. 13B.
- the parallel grooves of the light guide plate have the shape of the present invention, so that the parallel grooves have a hyperbola shape that can reduce unevenness of luminance compared to the conventional case. It can be seen that the unevenness of brightness or brightness can be further reduced, and the emission efficiency can be improved.
- the shape of the parallel groove of the light guide plate is made up of a pair of contour lines whose intervals are narrowed toward the light exit surface and intersect at the apex, and each contour line is perpendicular to the light exit surface. It has a part where the inclination angle with respect to a straight line changes, and the base end side (a pair of base end faces) of the parallel groove is more acute than the tip end side (a pair of front end faces) near the apex.
- the dynamic range of the halftone dot density can be narrowed, and the halftone dot pattern can be designed more easily. Accordingly, ink having various transmittances can be used as the ink used for forming the halftone dot pattern, and the selection range of the halftone ink material can be widened. In other words, the range of transmittance depending on the ink type can be widened.
- the transmittance of the halftone dot film itself can be improved.
- the range of brightness to be adjusted can be narrowed. That is, the arrangement density of halftone dots can be reduced, and the transmittance of the halftone dot pattern can be increased. Thereby, even when a halftone dot pattern is arranged, it is possible to emit more uniform light while suppressing a reduction in luminance of light emitted from the light exit surface, that is, maintaining high luminance.
- the emission efficiency can be further increased.
- the size of the parallel plane is not particularly limited.
- FIG. 17 when a large-sized light guide plate is configured by arranging a plurality of light guide plates 18 in parallel so that the light exit surfaces 18a of the light guide plate 18 all form the same plane, FIG. As shown in Fig. 17, the tangent line at the contact point between the inclined surface 18d of one light guide plate 18 and the inclined surface 18d 'of the other light guide plate 18' connected to the inclined surface 18d does not intersect, that is, the connecting portion of these inclined surfaces
- the inclination angle of the inclined surface 18d of the light guide plate 18 can be adjusted so that a smooth flat surface or curved surface is formed.
- the surfaces formed by the inclined surfaces 18d and 18d ′ of the light guide plates 18 and 18 ′ are formed to be in the shape of a church.
- a backlight unit having a large light irradiation surface can be obtained, and therefore, it is applied to a liquid crystal display device having a large display screen.
- a wall-mounted liquid crystal display device such as a wall-mounted television.
- the shape and angle of the inclined surface are not emitted by one block, but are emitted for several blocks and emitted from the light emitting surface. It is preferable that the light has a shape that makes the luminance distribution uniform.
- the light incident on the adjacent light guide plate is also emitted by the light emission surface force, so that more uniform light can be emitted and the emission efficiency can be improved.
- the light guide plates of the present invention formed separately are arranged or joined so that the thin-walled portions are in contact with each other.
- the light emission surfaces of the plurality of connected light guide plates are flat, that is, the force configured to be flush with each other.
- the light emission surfaces of the respective light guide plates are not necessarily flat.
- the light emission surface of the light guide plate may be configured to have the same curved surface when a plurality of light guide plates are connected, and a part of the light emission surface of the light guide plate may be partially formed. You may comprise so that it may become a curved surface. Or each light-guide plate can also be comprised so that the undulation of a fixed period may be formed in the whole surface of the light emission surface of a light-guide plate when two or more are connected.
- a sand rubbing surface, a large number of dimples or a large number of minute projections may be formed on the entire surface or a part of the light emitting surface, or a large number of scatterers may be formed by printing.
- Such sanding surfaces, dimples, protrusions, and scatterers suppress the generation of bright lines on the light exit surface of the light guide plate.
- a large-sized backlight unit when configured by connecting a plurality of light guide plates 18, brightness unevenness on the light emission surface of the connected light guide plates 18 is achieved. It is preferable to dispose one halftone dot sheet 350 on which halftone dots for suppressing the occurrence of light are formed so as to cover the light emission surfaces of the plurality of connected light guide plates 18.
- the halftone dot sheet 350 can be variously sized according to the number of light guide plates 18 to be connected.
- the halftone dots of the halftone dot sheet 18 generate bright lines on the light exit surface of the light guide plate 18. Placed in position.
- the material of such a halftone dot sheet 350 is made of the same material as that of the light guide plate 18 or a material having substantially the same coefficient of thermal expansion and high transmittance and diffusion effect from the viewpoint of suppressing the influence of thermal change. It is preferable.
- a halftone dot sheet By configuring a halftone dot sheet using such a material, the position of the halftone dot of the halftone sheet is changed from the generation position of the bright line on the light exit surface of the light guide plate due to temperature and humidity changes accompanying the production environment and use environment. The shift is suppressed, and a change in the illuminance distribution of the light emitted from the light exit surface of the light guide plate unit can be suppressed.
- the light guide plate may have a structure such that it is divided along the center line of the parallel groove for arranging the light source in the light guide plate 18 shown in FIG. 2B.
- the light guide plates are connected to each other at a portion corresponding to the parallel groove 18f of the light guide plate 18 having the structure shown in FIG. 2B. It is preferable to arrange the halftone dot sheet so as to coincide with the portion having the highest halftone dot density in the dot sheet. More
- a part of the light guide plates is constructed with a structure divided along the center line of the parallel grooves, and the other light guide plates are structured as shown in FIG. 2B.
- a halftone dot pattern on the halftone sheet so as to increase the density of halftone dots at positions corresponding to the center line of the parallel grooves of the light guide plate other than the connecting portion.
- a halftone dot pattern when a large-sized knock light unit is manufactured by connecting a plurality of light guide plates, generation of bright lines and unevenness at the connecting portions of the plurality of light guide plates are suppressed. be able to.
- Such a halftone dot sheet can be bonded to the light guide plate by laminating an adhesive layer on the back surface.
- the position of the halftone dot pattern formed on the halftone dots is defined as the center line of the parallel grooves of the light guide plates.
- the position corresponding to the position of the light guide plate for example, it is not used as the light emission area of the light emission surface of the light guide plate, and the position of the halftone sheet corresponding to that position is not used as the light emission area. It is preferable to form a positioning hole. By passing a fixture such as a pin through these positioning holes, the bright line generation position of the light guide plate and the halftone dot position of the halftone sheet can be accurately and reliably positioned.
- the position for forming the positioning hole is not particularly limited as long as it is not used as the light emission area, but the position corresponding to the halftone dot pattern and the center line of the parallel groove of the light guide plate due to the influence of temperature and humidity changes.
- a hole is formed in the center of the light exit surface in the direction perpendicular to the center line of the parallel groove of the light guide plate on the end side in the length direction of the parallel groove of the light guide plate. It is preferable to do.
- the halftone sheet is positioned relative to the light guide plate in the vicinity of the center of the combined light guide plates, and the outer peripheral portion is fitted with a gap only by thickness.
- the reflecting plate 24 may be disposed on the side surface of the light guide plate 18 as shown in FIG.
- the reflector 24 may be arranged on the side surface of the light guide plate 18 arranged on the outermost side.
- the side surface in the longitudinal direction of the light source 12 of the light guide plate 18 Further, as shown in FIGS. 29A and 29B, the side surface in the longitudinal direction of the light source 12 of the light guide plate 18 Further, a reflection plate 362 made of the same material as that of the reflection sheet 22 and the reflector described above may be disposed. As a result, the emission efficiency can be further improved, and the luminance unevenness at the end of the light guide plate 18 in the longitudinal direction of the light source 12 can be reduced.
- the luminance distribution of the light source is not flat in the longitudinal direction of the light source
- the light guide plate 18 The angle of the front end portion of the parallel groove 18f of the light guide plate 18 may be increased from the end portion (see FIG. 30B and FIG. 30D) toward the central portion (see FIG. 30C).
- the luminance distribution of the light source is not flat in the direction parallel to the light exit surface of the light guide plate and orthogonal to the longitudinal direction of the light source, or the brightness of light emitted from the light exit surface of the light guide plate
- the arrangement intervals of the plurality of light sources may be changed, that is, the width of each light guide plate may be adjusted according to the arrangement position. For example, if the brightness increases in the direction parallel to the light exit surface and perpendicular to the longitudinal direction of the light source, from the end to the center of the light guide plate, the light sources are equally spaced as shown in FIG. 31A. 31B, as shown in FIG.
- the arrangement of the light source 12 is such that the central force of the light guide plate 18 is further away in the direction parallel to the light exit surface 18a of the light guide plate 18 and perpendicular to the longitudinal direction of the light source 12. It may be a shape with a narrow interval.
- the light exit surface of the light guide plate is a curved surface having a curved cross-sectional shape on the surface orthogonal to the longitudinal direction of the light source, and is parallel to the light exit surface and orthogonal to the longitudinal direction of the light source.
- the luminance distribution of the light source or the luminance distribution of the emitted light may be flattened.
- the light guide plate 18 is used as the light source as shown in FIG.
- the cross-sectional shape of the surface perpendicular to the longitudinal direction of 12 is convex to the light source 12 side, and is an R-shaped curved surface that is parallel to the light exit surface of the light guide plate 18 and perpendicular to the longitudinal direction of the light source!
- the distance between the light source disposed on each light guide plate and the liquid crystal display panel 4 may be increased from the end of the light guide plate toward the center.
- the end portion 402 of the light guide plate 18 in the longitudinal direction of the light source 12 is connected to the light guide plate 18 as shown in FIG. It is good also as a shape which has the inclination of a predetermined angle from the direction perpendicular
- the light emission The end of the light guide plate in a direction parallel to the surface and perpendicular to the longitudinal direction of the light source may have a shape having an inclination of a predetermined angle from a direction perpendicular to the light exit surface of the light guide plate.
- uniform light can be emitted from the light exit surface by adjusting the shape of the light guide plate according to the light source.
- the light exit surface of the light guide plate 18 is a gently curved surface having a longitudinal cross-sectional shape of the light source 12 as shown in FIG. 34A.
- a rib 412 having a minute height extending in a direction orthogonal to the longitudinal direction of the light source 12 may be provided on the light exit surface of the light guide plate 19 as shown in FIG. Thereby, the deflection of the light guide plate in the direction orthogonal to the longitudinal direction of the light source can be prevented.
- the rib 412 also functions as a spacer that forms a predetermined gap between the light guide plate 18 and a sheet-like member that constitutes a backlight unit such as a diffusion sheet, and emits light that illuminates the liquid crystal display panel. Illuminance can be made more uniform.
- the position of the light source is regulated or temporarily fixed by attaching a reflection sheet to the inclined surface of the light guide plate 18 and extending the reflection sheet to the parallel grooves of the light guide plate. Please do it.
- the position of the light source with respect to the light guide plate becomes constant, and luminance unevenness can be reduced.
- the assembly of the knock light unit can be improved by temporarily fixing the light source.
- an elastic member that holds the cold cathode tube for example, a transparent O-ring 420 is provided at the end of the cold cathode tube. It may also be provided in the center.
- the elastic member acts as a buffer, so when the cold cathode tube is placed in the parallel groove of the light guide plate, the cold cathode tube collides with the parallel groove and the cold cathode tube is damaged. Can be prevented.
- the elastic member can be used as a cold cathode tube. Fixing improves handling in the assembly and manufacturing process.
- the parallel groove of the light guide plate is externally closed by closing the longitudinal side surface portion of the parallel groove of the light guide plate while holding the end portion of the cold cathode tube in the longitudinal direction with an electrode cover 422 such as a sponge. It is possible to prevent dust from entering the inside and prevent the cold cathode tube from being partially cooled.
- the prism sheet is arranged between the light exit surface side of the light guide plate and between the Z or the inclined surface of the light guide plate and the reflection sheet.
- 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, the light exit surface and the grooves directly on the axis of the rod-shaped light source on the Z or inclined surface. May be engraved with parallel prisms.
- the prism 25 may be formed directly on the inclined surface 18d of the light guide plate 18 as shown in FIG. 19A and FIG. 19B, and the prism 26 is formed on the light exit surface 18a of the light guide plate 18 as shown in FIG.
- the prism 25 may be formed on the inclined surface 18d.
- the same effect as when the prism sheet is arranged can be obtained. it can. Furthermore, since it is not necessary to provide a prism sheet, light attenuation (decrease in luminance) caused by the gap formed by arranging the prism sheet can be eliminated. As a result, the light use efficiency as the planar illumination device, that is, the light emission efficiency can be made higher than that in the case where the prism sheet is arranged. Furthermore, since it is not necessary to provide a prism sheet, the apparatus can be made smaller (thinner).
- the interval is narrowed toward the light exit surface, and the contour is composed of a pair of contour lines that intersect at the apex, and the inclination angle of each contour line with respect to a line perpendicular to the light exit surface changes.
- the light guide plate has a shape with a sharper angle on the base side (a pair of base end surfaces) of the parallel groove that is far from the apex than the front end side (a pair of front end surfaces) near the apex.
- the present invention is not limited to this, and the parallel groove has a shape in which the inclination of the proximal end face is not steep with respect to the inclination of the distal end face such as a triangle as shown in FIG.
- the prism engraved on the inclined surface has an apex angle of 70 ° ⁇ ⁇ ⁇ 140 °.
- the prism formed on the light exit surface has an apex angle 0 of 40 ° ⁇ ⁇ ⁇ 70 °.
- the emission efficiency as the planar illumination device can be improved more suitably.
- FIGS. 36A to 36C show an example of a light guide plate in which prisms are engraved on inclined and parallel surfaces.
- 36A is a schematic diagram showing the parallel surface and the inclined surface of the light guide plate 18, and
- FIG. 36B is an enlarged schematic diagram showing the prism 27 engraved on the parallel surface 18g, and
- FIG. 36C shows the inclined surface 18d.
- FIG. 3 is a schematic diagram showing an enlarged prism 25.
- the light guide plate 18 has a prism 25 engraved on the inclined surface 18d and a prism 27 engraved on the parallel surface 18g.
- the prism 27 engraved on the parallel surface 18g has an isosceles triangular shape with an apex angle of 82 degrees, and is engraved on the inclined surface 18d as shown in FIG. 36C.
- the prism 25 has an isosceles triangle shape with an apex angle of 120 degrees.
- the emission efficiency can be improved by engraving the prism satisfying the above range on the inclined surface. Further, the emission efficiency can be further improved by forming prisms on the parallel surfaces.
- the prism 25 formed on the inclined surface 18d has a shape that is perpendicular to the bottom surface and symmetrical to the surface passing through the apex, that is, a prism formed on the inclined surface. 25 is shaped so that the angle between the surface perpendicular to its bottom surface and passing through its apex and the surface of the prism 25 is 60 degrees.
- prisms formed on inclined surfaces and parallel surfaces are used. Is more preferably an asymmetric shape with respect to the plane perpendicular to the bottom surface and passing through the apex.
- the bottom surface of the prism is a virtual surface that faces the apex angle of the prism, that is, a virtual surface that connects contacts with adjacent prisms of the prism, that is, an end of the prism on the parallel groove side. It is a virtual surface connecting the end on the thin end side.
- the angle distribution characteristic is the luminance distribution characteristic with respect to the viewing angle of the light emitted from the knocklight unit, and the luminance distribution unevenness with respect to the viewing angle is uniformed by uniforming the angle distribution characteristic at an arbitrary point of the light guide plate. Can be suppressed.
- the angle ( ⁇ 1) between the surface perpendicular to the bottom surface and passing through the vertex and the surface on the parallel groove side is 0 ° or more. 70 degrees or less, that is, 0 ° ⁇ ⁇ 1 ⁇ 70 °, and the angle (0 2) between the surface perpendicular to the bottom surface and passing through the vertex and the surface on the thin end side is 45 degrees or more 70 It is preferable that the angle is less than 45 °, that is, 45 ° ⁇ ⁇ 2 ⁇ 70 °. Further, 0 1 is more preferably 30 degrees or more and 70 degrees or less, that is, 30 ° ⁇ ⁇ 1 ⁇ 70 °.
- the prism 25 formed on the inclined surface 18d is perpendicular to the bottom surface ( ⁇ line in FIG. 36D) and passes through the apex ( ⁇ line in FIG. 36D).
- the angle between the parallel groove side surface (hereinafter referred to as ⁇ 1) is 60 degrees
- the angle between the surface and the surface (hereinafter referred to as ⁇ 2) is 55 degrees
- ⁇ 1 is 60 degrees and ⁇ 2 is 50 degrees, as shown in Fig. 36 ⁇ , or 0 as shown in Fig. 36F.
- the light exit surface force can also make the angle distribution characteristics of the emitted light uniform and improve the front luminance. it can. Furthermore, by setting 0 1 to 30 ° ⁇ ⁇ 1 ⁇ 70 °, the apex angle of the prism will be greater than the ⁇ power degree, and the output efficiency as a planar illumination device will be improved more favorably. Can do.
- all the prisms formed on the inclined surface have a shape that is perpendicular to the bottom surface and asymmetric with respect to the surface passing through the apex.
- the present invention is not limited to this.
- the light exit surface force makes the angle distribution characteristics of the emitted light uniform. And the front luminance can be improved.
- FIGS. 37A to 37E shows the inclination surface in the direction orthogonal to the parallel groove.
- FIG. 37A is a schematic diagram showing a parallel surface and an inclined surface of the light guide plate 18.
- a prism 27 is engraved on the parallel surface 18g.
- the A region, the B region, and the C region from the portion in contact with the parallel surface 18g of the inclined surface 18d to the portion connected to the inclined surface of the adjacent light guide plate.
- Different shapes of prisms are formed in the three areas. That is, the prism 25a is provided in the A region on the parallel plane side, the prism 25b is provided in the B region on the thinner end side than the A region, and the prism 25c is provided in the C region on the thinner end side than the B region. It is engraved.
- FIGS. 37A to 37D The shapes of the prisms formed on the parallel surface, A region, B region, and C region of the light guide plate 18 are shown in FIGS. 37A to 37D, respectively.
- Fig. 37B is a schematic diagram of the prism 27 engraved on the parallel surface
- Fig. 37C is a schematic diagram of the prism 25a engraved in the area A of the inclined surface 18d
- Fig. 37D is an illustration of the inclined surface 18d.
- FIG. 37E is a schematic diagram of the prism 25b engraved in the area B
- FIG. 37E is a schematic diagram of the prism 25c engraved in the area C of the inclined surface 18d.
- the prism 27 has an isosceles triangular shape with an apex angle of 82 degrees, that is, a symmetrical shape.
- the prism 25a has a triangular shape with ⁇ 1 of 60 degrees and ⁇ 2 of 45 degrees
- the prism 25b has a triangle with ⁇ 1 of 60 degrees and ⁇ 2 force of 0 degrees.
- the prism 25c has a triangular shape in which ⁇ 1 is 60 degrees and ⁇ 2 is 60 degrees.
- Fig. 38 shows another example of the case in which different shapes are engraved according to the position of the inclined surface in the direction orthogonal to the parallel grooves.
- an isosceles triangular prism 27 having an apex angle of 82 degrees is engraved on the parallel surface of the light guide plate.
- a ′ region, B ′ region, C ′ region, D, region, E In five regions, prisms 25a, 25b ′, 25c ′, 25d, and 25e ′ are engraved, respectively.
- prism 25a ' is engraved in a triangular shape with 0 1 force 0 degree and 0 2 at 55 degrees
- prism 25b' has a triangular shape with ⁇ 1 at 60 degrees and ⁇ 2 at 50 degrees
- Prism 25c ' is engraved with a triangular shape with ⁇ 1 of 60 degrees and ⁇ 2 of 60 degrees
- prism 25d' has a triangular shape with 0 1 degrees 0 degrees and 0 2 of 50 degrees
- the prism 25 e ′ is engraved in a triangular shape with 0 1 being 60 degrees and 0 2 being 60 degrees.
- the light exit surface force makes the angular distribution characteristics of the emitted light more uniform.
- the front luminance can be further improved.
- the length of the base of the prism in the direction orthogonal to the parallel grooves is 0.1 mm or less.
- the number, width, and ratio of the prism regions formed on the inclined surface and the parallel surface are not particularly limited, and can be any number, width, and ratio.
- the prism formed on the parallel surface is shaped symmetrically with respect to the surface perpendicular to the bottom surface and passing through the apex, but of course, it may be asymmetrical.
- the arrangement pattern of the prisms is not particularly limited, and it is needless to say that various arrangement patterns may be used as necessary.
- the prisms to be engraved are divided for each region, but the present invention is not limited to this.
- a triangular prism having ⁇ 1 force 60 degrees and ⁇ 2 force 50 degrees, and ⁇ Triangular prisms with 1 force of 60 degrees and ⁇ 2 force of 50 degrees may be formed alternately.
- the prisms engraved on the inclined surfaces and the parallel surfaces are symmetrical with respect to the center line perpendicular to the light exit surface through the centers of the parallel grooves.
- U preferred to engrave (form).
- the method for forming the prism is not particularly limited, and the prism may be formed by cutting an inclined surface or may be provided with a prism.
- the prism may be formed.
- a light guide plate on which a prism is formed may be produced using a mold on which a prism is formed.
- a convex portion on the light exit surface 18a of the light guide plate 18.
- a convex part with a rounded upper part such as an ellipse cut in half, is placed at the boundary between adjacent light guide plates with a certain height and width in a direction parallel to the parallel groove.
- the height of the convex portion is not particularly limited, but may be a height that can be sufficiently reduced by the uneven luminance force on the light exit surface 18a of the light guide plate 18 and the film member disposed thereon.
- the shape of the convex portion is not particularly limited, and the cross-sectional shape of the convex portion may be, for example, a rectangle, a trapezoid, a semicircle, or a triangle.
- the position of the convex portion formed on the light exit surface 18a of the light guide plate 18 is not particularly limited, and can be provided at an arbitrary position.
- the number of convex portions is not limited. For example, three or more convex portions can be formed on the light guide plate.
- the convex portions formed on the light exit surface of the light guide plate may be formed integrally with the light guide plate at the time of manufacturing the light guide plate, or may be flat after the light guide plate having a flat light exit surface is manufactured. Parts that become convex portions may be arranged on the light exit surface. From the viewpoint of ease of manufacture, it is preferable to form the light guide plate integrally.
- the convex part formed in the light emission surface can be used as a spacer for securing a space between the optical member constituting the knock light unit and the light emission surface.
- a film-like optical member such as a prism sheet or a diffusion sheet disposed on the light exit surface is used as a spacer for separating the flat portion force of the light exit surface by a predetermined distance. be able to. That is, unevenness in luminance can be reduced by forming convex portions on the light exit surface.
- the manufacturing becomes easy as described above, and it is not necessary to adjust the alignment between the light guide plate and the convex portion when assembling.
- a halftone dot sheet 32 is arranged on the light exit surface of the light guide plate 18, and the halftone dot plate 39 is arranged thereon by being supported by the convex portions 18p.
- the convex portion 18p formed on the light emitting surface 18a is an independent member that is not formed integrally with the light guide plate 18, and has a rectangular cross-sectional shape.
- prisms are engraved on the inclined surface and the parallel surface as in FIG.
- the halftone dot pattern of the halftone dot sheet 32 arranged on the side is composed of a pattern for suppressing high-frequency luminance unevenness, and is arranged away from the light exit surface 18a by the height of the convex portion 18p. It is preferable that the 39 dot patterns are configured with patterns that suppress luminance unevenness at low frequencies. With this configuration, it is possible to effectively suppress the occurrence of uneven brightness of illumination light.
- high-frequency luminance unevenness means that the distance between an arbitrary point xl and point x2 on the light exit surface of the light guide plate is dx [mm], and the luminance Bl [cdZm 2 ] at point xl and luminance B2 [ cdZm 2 ]
- dBZdx the luminance Bl [cdZm 2 ] at point xl and luminance B2 [ cdZm 2 ]
- the distance between the two points dx force is 0. lm m dx Shall mean.
- low-frequency brightness unevenness means brightness unevenness where
- the force of disposing only the brightness enhancement film 39 on the surface on the light emitting side of the halftone plate 39, the above-described diffusion sheet, optical compensation film, prism sheet, and the like are disposed. It is preferable to further diffuse light and to improve Z or luminance.
- the planar illumination device is described as being used as the backlight unit of the liquid crystal display device.
- the present invention is not limited to this, and the planar illumination device illuminates the interior and the exterior. It can be used as a planar lighting device for backlights such as lighting devices, advertising panels, advertising towers and billboards.
- planar lighting device used as a lighting device such as an indoor lighting device or a signboard will be described together with specific examples.
- FIG. 40 is a schematic perspective view showing one embodiment of the planar lighting device of the present invention and showing an appearance viewed from the light emitting surface side.
- 41A, FIG. 41B, FIG. 41C, and FIG. 41D are a front view, a bottom view, a side view, and a rear view of the planar illumination device shown in FIG. 40, respectively.
- Figure 42 FIG. 40 is a partial cross-sectional view of an embodiment of the planar lighting device shown in FIG.
- FIG. 40 in order to facilitate understanding, they are shown enlarged in the direction of the thickness of the planar lighting device.
- the planar illumination device 500 includes an illumination device body 514 that emits uniform light from a rectangular light emission surface 514a, and an illumination device body 514 inside.
- the light emitting surface 514a side (front surface side) is provided with a casing 516a having a rectangular opening 516a formed thereon, and attached to the light emitting surface 514a opposite to the light emitting surface 514a (back surface side).
- a power source 538 (see FIG. 44) for lighting a plurality of linear light sources 512.
- the illumination device main body 514 includes a plurality of light sources 12, a diffusion sheet 14, prism sheets 16, 17, a connection light guide plate 522, a reflector 20, and a reflection. And plate 22.
- the illumination device body 514 has the same configuration as the planar illumination device 2 shown in FIGS. 1 and 2 except for the connection light guide plate 522 in which a plurality of light guide plates 523 are connected. Is omitted.
- the connected light guide plate 522 is formed by connecting a plurality of light guide plates 523.
- the connection light guide plate 522 is integrally formed with a plurality of light guide plates 523 connected.
- the connection light guide plate 522 has a structure in which the light guide plates 523 adjacent to each other in the direction orthogonal to the parallel groove 522b are connected to each other by the thin end portions 523c, and the connection portion of the thin end portions 523c is the thinnest of the connection light guide plates 522.
- a part 522 is formed.
- the light emission surfaces 523a of the plurality of light guide plates 523 are connected to be flush with each other, and the light guide plate 522 has a uniform light emission surface 522a.
- one light guide plate 523 is the same as that of the light guide plate 18 described above except that the thin end portion 23c side of the inclined surface 23d has a curved shape as shown in FIG.43B. Detailed description thereof is omitted.
- a plurality of light guide plates formed of a plurality of light guide plates 523 are connected.
- the light guide plate assembly is connected to the thin end 523c of the light guide plate 523 of the adjacent connection light guide plate and connected in a direction orthogonal to the parallel groove 522b, and is increased in size to emit light.
- the surface 522a may have a large area, the thin end 523c of the adjacent connecting light guide plate may be connected to the same end, and connected in a direction parallel to the parallel groove 522b to increase the size.
- the light exit surface 522a may have a large area, or these may be performed simultaneously and connected in a direction parallel to and perpendicular to the parallel groove 522b to further increase the size of the light exit surface 522a. You may do it.
- the uniform planar light emitting surfaces of the plurality of connected light guide plates are connected to be flush with each other, and the light guide plate assembly forms a uniform planar light emitting surface. Absent.
- the length of the light exit surface 523a of the light guide plate 523 in the direction perpendicular to the longitudinal direction of the light source 12 is 28 mm and parallel to the longitudinal direction of the light source 12 7 light guide plates with a length of 560 mm in the vertical direction are connected and integrally molded, and the length of the light output surface 522 a in the direction perpendicular to the longitudinal direction of the light source 12 is 196 mm, and the length of the light source 12 is Three light guide plates 522 having a light emission surface 522a of 560 mm in the direction parallel to the direction are manufactured, and the three light guide plates 522 are connected in a direction perpendicular to the parallel grooves 522b.
- a light guide plate assembly having a light emission surface length of 588 mm in the direction perpendicular to the longitudinal direction and a light emission surface length of 560 mm in the direction parallel to the longitudinal direction of the light source 12 is exemplified.
- a light guide plate assembly in which a plurality of connected light guide plates having different numbers of connected light guide plates is connected can also be used.
- the length of the light exit surface 523a of the light guide plate 523 in the direction perpendicular to the longitudinal direction of the light source 12 is 28 mm
- the length of the light exit surface 522a in the direction parallel to the longitudinal direction of the light source 12 is 715 mm.
- Twelve light guide plates are connected and integrally molded.
- the length of the light emission surface 522a in the direction perpendicular to the longitudinal direction of the light source 12 is 336 mm, and the length of the light emission surface 522a in the direction parallel to the longitudinal direction of the light source 12 is
- Two 715 mm connected light guide plates 522 are manufactured, and the light exit surface 523a of the light guide plate 523 in the direction perpendicular to the longitudinal direction of the light source 12 is 28 mm, and the light in the direction parallel to the longitudinal direction of the light source 12 is obtained.
- Light is emitted in a direction perpendicular to the longitudinal direction of the light source 12 by connecting 13 light guide plates with an emission surface 522a of 715mm in length.
- a single connected light guide plate 522 having a length of the light emission surface 522a of 364 mm and a length of light emission surface 522a of 715 mm in the direction parallel to the longitudinal direction of the light source 12 is produced, and the three connected light guide plates 522 are parallel.
- the length of the light emission surface in the direction perpendicular to the longitudinal direction of the light source 12 connected in the direction orthogonal to the groove 522b is 715 mm
- the length of the light emission surface in the direction parallel to the longitudinal direction of the light source 12 is 1036 mm.
- a light guide plate assembly having a light exit surface is exemplified.
- the inclined back surface may be cut and the gap filled with PMMA composite material.
- the housing 516 accommodates and supports the lighting device main body 514, and is sandwiched and fixed from the light emission surface 514a side, the reflector 20, and the reflection sheet 22 side.
- the upper surface is opened, and the lighting device body 514 is housed and supported from above, and the lower housing 530 that covers the four side surfaces of the lighting device body 514 and the rectangular light emitting surface 514 of the lighting device body 514 are smaller than the upper surface.
- a rectangular opening serving as the opening 16a is formed on the bottom surface, the lower surface is opened, and the upper force is applied to cover the lighting device main body 514 and the lower housing 530 in which the lighting device main body 514 is stored, including its four side surfaces.
- the upper casing 532, the lower casing 530, and the concave (U-shaped) folding member 534 inserted between the sidewalls of the upper casing 532 and the lower casing 532, and the bottom casing 530 are connected to each other.
- the back surface 522d of the light guide plate 522 is supported via the reflection sheet 22, and the lighting device body 514 And a light guide plate support member 536 that also supports the whole.
- an inverter storage portion 520 (see FIG. 41) for storing a plurality of inverter units 518 is attached to the back side of the lower housing 530.
- the joining method of the lower casing 530 and the folding member 534 various methods such as a method using bolts and nuts, a method using an adhesive, etc.
- a known method can be used.
- the upper casing 532 is at least larger than the lower casing 530, and is connected to the illuminating device body 514.
- the parallel grooves 522b of the light guide plate 522 or the outer sides of both ends of the lower casing 530 parallel to the linear light source 12 accommodated therein.
- the folding member 534 needs to be disposed in each gap between the wall surface and the inner wall surfaces of the upper casing 532 facing each other.
- the folding member 534 is arranged on the four sides of the casing 516 in the lower casing 530. It may be arranged between the side wall of the upper casing 532 and the side wall of the upper casing 532. It is also preferable to attach a reinforcing member that reinforces the concave portion of the concave folded member 534. Yes.
- the rigidity of the housing 516 can be increased, and light can be emitted uniformly and efficiently. Specifically, even if the connected light guide plate 522 is likely to be warped due to the presence of the parallel grooves 522b, it is possible to correct the warp or prevent the connected light guide plate 522 from being warped, thereby causing uneven brightness. Excellent optical characteristics can be obtained. Further, by attaching a reinforcing member that reinforces the concave portion of the folding member 534, the rigidity of the housing 516 can be increased, and the warpage of the connection light guide plate 522 can be more preferably prevented. Thereby, better optical characteristics can be obtained. A commercially available color temperature conversion filter may be used to convert the color temperature.
- the light guide plate support portion 536 is formed of a resin such as polycarbonate, and in the illustrated example, the shape of the back surface 522d of the thinnest portion 522c of the connection light guide plate 522, that is, two connected light guides.
- the thinnest part of the light guide plate 522 is not limited to this, and convex portions having a shape obtained by inverting the shape of the back surface 522d of the connection light guide plate 522 have a predetermined interval.
- a continuous member may be provided.
- the housing 516 includes a bracket such as an L-shaped metal fitting that joins its four corners, or between the diffusion sheet 14 of the planar device main body 514 and the peripheral portion of the opening 514a of the upper housing 530.
- An elastic member that has an elastic material force such as rubber, or a protective member that protects the entire upper surface of the diffusion sheet 14 of the planar device main body 514 may be provided.
- the casing 516 is basically configured as described above.
- the drive device 537 shown in FIG. 44A and FIG. 44B drives a plurality of linear light sources 12 such as CCFLs, that is, turns on and off, and drives the illumination of the surface illumination device 500.
- FIG. 44B shows the detailed configuration of the inverter unit 518.
- a block diagram of a driving device 537 for lighting a linear light source 12 such as one CCFL is shown.
- the power source 538 is a DC power source that outputs a DC voltage, for example, a DC voltage of 24V. This DC voltage is supplied to each of the plurality of inverter units 518 connected to the power source 538.
- the inverter unit 518 is connected to the linear light source 12 and the drive circuit 518a that generates a primary AC signal having a predetermined frequency (eg, 650 Vp-p) from a DC voltage supplied from the power supply 538.
- the primary side AC signal generated by the drive circuit 518a is boosted to the high-voltage secondary side AC signal (for example, 6500Vp-p, 1000-2400Vrms) required to turn on the linear light source 12 such as CCFL.
- the transformer 518b is connected to the linear light source 12 such as CCFL, and the tube current detection circuit 518c for detecting the tube current and the tube current output from the tube current detection circuit 518c are fed back to the drive circuit 518a.
- a voltage-controlled oscillation circuit 518d that oscillates a clock (fundamental wave) having a predetermined frequency for generating the secondary AC signal in accordance with the fed-back tube current.
- the plurality of linear light sources 12 can be turned on simultaneously and uniformly, efficiently and stably. Light can be emitted with uniform brightness.
- only a part may be turned on by the force inverter unit 518 that turns on the plurality of linear light sources 12 at the same time, or these may be switched.
- the linear light source driving device and the planar illumination device are basically configured as described above.
- inverter 518 on the back side of housing 516 as in the present embodiment, the area of the edge of housing 516 can be reduced.
- the planar lighting device 500 is provided with the inverter storage portion 520 on the back side of the casing 516, and the force used to store the plurality of inverter units 518.
- the planar lighting device of the present invention is However, the present invention is not limited to this, and a lower casing 530 and an upper section are formed at the periphery of the opening 516a of the casing 516 on the side orthogonal to the linear light source 12 like the planar lighting device 501 shown in FIG.
- a space may be provided between the housing 532 and the inverter storage portion 520, and a plurality of inverter units 518 may be stored.
- the back surface of the planar lighting device 501 that is, the back surface of the housing 516 can be flattened, and can be easily attached to the ceiling or wall surface.
- the planar lighting device can be thinned.
- the above-described various aspects can also be applied to light guide plates having various shapes described in JP 2005-234397 A.
- it can be suitably used for a light guide plate in which the shape of the parallel grooves is a hyperbola.
Abstract
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
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JP2007502608A JPWO2006085526A1 (ja) | 2005-02-08 | 2006-02-07 | 導光板、これを用いる面状照明装置および液晶表示装置 |
EP06713197A EP1847767A4 (en) | 2005-02-08 | 2006-02-07 | LIGHT GUIDE PLATE, AND PLANAR LIGHTING DEVICE AND LIQUID CRYSTAL DISPLAY DEVICE USING THE LIGHT GUIDE PLATE |
US11/883,889 US20080137004A1 (en) | 2005-02-08 | 2006-02-07 | Light Guide Plate, and Planar Lighting Device and Liquid Crystal Display Device Using Such Light Guide Plate |
Applications Claiming Priority (10)
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JP2005032231 | 2005-02-08 | ||
JP2005-032231 | 2005-02-08 | ||
JP2005041398 | 2005-02-17 | ||
JP2005-041398 | 2005-02-17 | ||
JP2005122368 | 2005-04-20 | ||
JP2005-122368 | 2005-04-20 | ||
JP2005-237508 | 2005-08-18 | ||
JP2005237508 | 2005-08-18 | ||
JP2006-013873 | 2006-01-23 | ||
JP2006013873 | 2006-01-23 |
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PCT/JP2006/302054 WO2006085526A1 (ja) | 2005-02-08 | 2006-02-07 | 導光板、これを用いる面状照明装置および液晶表示装置 |
Country Status (4)
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US (1) | US20080137004A1 (ja) |
EP (1) | EP1847767A4 (ja) |
JP (1) | JPWO2006085526A1 (ja) |
WO (1) | WO2006085526A1 (ja) |
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KR100835005B1 (ko) * | 2001-12-24 | 2008-06-04 | 엘지디스플레이 주식회사 | 백라이트 유닛 |
TW575722B (en) * | 2002-09-02 | 2004-02-11 | Hannstar Display Corp | Planar light source device and liquid crystal display |
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2006
- 2006-02-07 JP JP2007502608A patent/JPWO2006085526A1/ja active Pending
- 2006-02-07 US US11/883,889 patent/US20080137004A1/en not_active Abandoned
- 2006-02-07 WO PCT/JP2006/302054 patent/WO2006085526A1/ja active Application Filing
- 2006-02-07 EP EP06713197A patent/EP1847767A4/en not_active Withdrawn
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Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7798681B2 (en) | 2007-08-14 | 2010-09-21 | Foxsemicon Integrated Technology, Inc. | Light guide block and related illumination device and backlight module having the same |
CN109782489A (zh) * | 2019-03-28 | 2019-05-21 | 京东方科技集团股份有限公司 | 一种背光模组及显示装置 |
Also Published As
Publication number | Publication date |
---|---|
US20080137004A1 (en) | 2008-06-12 |
EP1847767A4 (en) | 2013-01-23 |
EP1847767A1 (en) | 2007-10-24 |
JPWO2006085526A1 (ja) | 2008-06-26 |
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