WO2012099099A1 - 面光源装置及び液晶表示装置 - Google Patents
面光源装置及び液晶表示装置 Download PDFInfo
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- WO2012099099A1 WO2012099099A1 PCT/JP2012/050802 JP2012050802W WO2012099099A1 WO 2012099099 A1 WO2012099099 A1 WO 2012099099A1 JP 2012050802 W JP2012050802 W JP 2012050802W WO 2012099099 A1 WO2012099099 A1 WO 2012099099A1
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- light
- light source
- emitting
- liquid crystal
- light guide
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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
- G02B6/0075—Arrangements of multiple light guides
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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
- G02B6/0018—Redirecting means on the surface of the light guide
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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
- G02B6/0028—Light guide, e.g. taper
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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
- G02B6/0051—Diffusing 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
- G02B6/0066—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
- 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
- G02F1/133615—Edge-illuminating devices, i.e. illuminating from the side
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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
- G02B6/0025—Diffusing sheet or layer; Prismatic 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
- G02B6/0035—Means for improving the coupling-out of light from the light guide provided on the surface of the light guide or in the bulk of it
- G02B6/0036—2-D arrangement of prisms, protrusions, indentations or roughened surfaces
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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
- G02B6/0058—Means for improving the coupling-out of light from the light guide varying in density, size, shape or depth along the light guide
- G02B6/0061—Means for improving the coupling-out of light from the light guide varying in density, size, shape or depth along the light guide to provide homogeneous light output intensity
Definitions
- the present invention relates to a surface light source device having a planar light emitting surface, and a liquid crystal display device having a surface light source device and a liquid crystal panel.
- a backlight unit of a liquid crystal display device light from a light source is incident on a side surface (light incident surface) of a thin plate-like surface light-emitting light guide plate, and diffused light is liquid crystal from the front surface (light-emitting surface) of the surface light-emitting light guide plate.
- a sidelight type surface light source device that emits light toward the entire rear surface of a display element (liquid crystal panel) is widely used.
- the sidelight surface light source device since it is difficult to install a large number of light sources (for example, LEDs) facing a narrow surface such as the side surface of a thin plate-like surface light-emitting light guide plate, the sidelight surface light source device has sufficient luminance. There was a problem that it was difficult to improve it.
- a plurality of light sources (a plurality of light emitting element arrays) arranged in the thickness direction of the surface light source device, a surface light emitting light guide plate, and a light from the plurality of light sources are incident on the side surface of the surface light emitting light guide plate
- an optical path changing member for example, a light reflecting mirror
- the thickness of the liquid crystal display device increases.
- an object of the present invention is to provide a surface light source device and a display surface capable of realizing both an improvement in luminance of a light emitting surface and a thin structure.
- An object of the present invention is to provide a liquid crystal display device capable of realizing both an improvement in luminance and a thin structure.
- a surface light source device includes a light emitting surface, a back surface opposite to the light emitting surface, and a plurality of side surfaces connecting a side of the light emitting surface and a side of the back surface.
- a surface-emitting light-guiding plate that emits light incident from a light incident surface, which is one of the side surfaces, from the light emitting surface, and is disposed to face the light incident surface, and is first facing the light incident surface.
- a first light source that emits a light beam; a second light source that emits a second light beam; and an optical path changing member that guides the second light beam emitted from the second light source to the light incident surface. Both the emitted first light beam and the second light beam emitted from the second light source enter the surface-emitting light guide plate from the light incident surface which is the same side surface among the plurality of side surfaces. It is a feature.
- a liquid crystal display device includes a liquid crystal panel and the surface light source device that irradiates the back surface of the liquid crystal panel with planar light.
- the surface light source device it is possible to realize both the improvement of the luminance of the light emitting surface and the thin structure.
- the liquid crystal display device according to the present invention it is possible to realize both an improvement in luminance of the display surface and a thin structure.
- FIG. 2 is a block diagram schematically showing a configuration of a control system of the liquid crystal display device of Embodiment 1.
- FIG. It is sectional drawing which shows typically an example of the surface emitting light-guide plate (light-guide diffusion plate) in the surface light source device of Embodiment 1, and its peripheral structure. It is sectional drawing which shows typically the surface emitting light-guide plate in the surface light source device of Embodiment 1, and the other example of its periphery structure.
- FIG. 3 is a diagram schematically showing an example of arrangement of micro optical elements provided on a surface light-emitting light guide plate in the surface light source device of the first embodiment. It is sectional drawing which shows typically the surface emitting light-guide plate in the surface light source device of Embodiment 1, and the other example of its periphery structure. It is sectional drawing which shows typically the surface emitting light guide plate in the surface light source device of Embodiment 1, and the further another example of its periphery structure. It is sectional drawing which shows roughly an example of a structure of the liquid crystal display device (including surface light source device) of Embodiment 2 which concerns on this invention. 6 is a block diagram schematically showing a configuration of a control system of a liquid crystal display device according to a second embodiment. FIG.
- FIG. 5 is a block diagram schematically showing a configuration of a control system of a liquid crystal display device according to a third embodiment. It is sectional drawing which shows roughly an example of a structure of the liquid crystal display device (including surface light source device) of Embodiment 4 which concerns on this invention. It is sectional drawing which shows typically an example of the surface emitting light-guide plate in the surface light source device of Embodiment 4, and its peripheral structure. It is sectional drawing which shows roughly an example of a structure of the liquid crystal display device (including surface light source device) of Embodiment 5 which concerns on this invention.
- FIG. 5 is a block diagram schematically showing a configuration of a control system of a liquid crystal display device according to a third embodiment. It is sectional drawing which shows roughly an example of a structure of the liquid crystal display device (including surface light source device) of Embodiment 4 which concerns on this invention. It is sectional drawing which shows typically an example of the surface emitting light-guide plate in the surface light source device of Embodiment 4, and its
- FIG. 10 is a cross sectional view schematically showing another example of the diffusion structure in the fifth embodiment.
- FIG. 12 is a cross sectional view schematically showing still another example of the diffusion structure in the fifth embodiment.
- It is sectional drawing which shows roughly the other example of the light guide member for light sources in Embodiment 5.
- FIG. It is sectional drawing which shows roughly an example of a structure of the liquid crystal display device (including surface light source device) of Embodiment 6 which concerns on this invention.
- It is the schematic plan view which looked at the surface light source device shown by FIG. 18 from the liquid crystal panel side.
- It is the schematic rear view which looked at the surface light source device shown by FIG. 18 from the back side of the liquid crystal display device.
- FIG. 10 is a block diagram schematically showing a configuration of a control system of a liquid crystal display device according to a sixth embodiment. It is sectional drawing which shows roughly an example of a structure of the liquid crystal display device (a surface light source device is included) which is a modification of Embodiment 6 which concerns on this invention. It is sectional drawing which shows roughly an example of a structure of the liquid crystal display device (including surface light source device) of Embodiment 7 which concerns on this invention. It is a perspective view which shows roughly an example of a structure of the light reflection member of the surface light source device shown by FIG. FIG.
- FIG. 24 is a cross sectional view schematically showing another example of the light reflecting member of the surface light source device in the liquid crystal display device of the seventh embodiment. It is sectional drawing which expands and shows the structure of the light reflection member of the surface light source device shown by FIG.
- FIG. 24 is a cross sectional view schematically showing another example of the light reflecting member of the surface light source device in the liquid crystal display device of the seventh embodiment.
- FIG. 24 is a cross sectional view schematically showing another example of the light reflecting member of the surface light source device in the liquid crystal display device of the seventh embodiment. It is sectional drawing which shows roughly an example of a structure of the liquid crystal display device (including surface light source device) of Embodiment 8 which concerns on this invention.
- FIG. 25 is a cross sectional view schematically showing another example of the configuration of the liquid crystal display device (including the surface light source device) according to the eighth embodiment.
- FIG. 20 is a cross sectional view schematically showing another example of the light guide member for light source in the eighth embodiment.
- FIG. 25 is a cross sectional view schematically showing another example of the configuration of the liquid crystal display device (including the surface light source device) according to the eighth embodiment. It is sectional drawing which shows roughly an example of a structure of the liquid crystal display device (including surface light source device) of Embodiment 9 which concerns on this invention.
- FIG. 20 is a cross sectional view schematically showing another example of the light guide member for light source in the eighth embodiment.
- FIG. 25 is a cross sectional view schematically showing another example of the configuration of the liquid crystal display device (including the surface light source device) according to the eighth embodiment. It is sectional drawing which shows roughly an example of a structure of the liquid crystal display device (including surface light source device) of Embodiment 9 which concerns on this
- FIG. 32 is a cross sectional view schematically showing another example of the light reflecting member of the surface light source device in the liquid crystal display device according to the ninth embodiment.
- FIG. 32 is a cross sectional view schematically showing another example of the light reflecting member of the surface light source device in the liquid crystal display device according to the ninth embodiment.
- FIG. 32 is a cross sectional view schematically showing another example of the light reflecting member of the surface light source device in the liquid crystal display device according to the ninth embodiment.
- FIG. 25 is a cross sectional view schematically showing another example of the configuration of the liquid crystal display device (including the surface light source device) according to the ninth embodiment. It is a figure which shows the structure of the light-incidence surface vicinity of the surface emitting light-guide plate of the surface light source device shown by FIG. FIG.
- FIG. 25 is a cross sectional view schematically showing another example of the configuration of the liquid crystal display device (including the surface light source device) according to the ninth embodiment. It is sectional drawing which shows roughly an example of a structure of the liquid crystal display device (including surface light source device) of Embodiment 10 which concerns on this invention.
- FIG. 38 is a block diagram schematically showing a configuration of a control system of the liquid crystal display device according to the tenth embodiment.
- FIG. 16 is a conceptual diagram of the liquid crystal display device according to the tenth embodiment as viewed in the ⁇ z-axis direction.
- FIG. 16 is a conceptual diagram of the liquid crystal display device according to the tenth embodiment when viewed in the + z-axis direction.
- FIG. 32 is a conceptual diagram of the liquid crystal display device according to the eleventh embodiment as viewed in the ⁇ z-axis direction.
- FIG. 38 is a cross sectional view schematically showing another example of the diffusion structure in the eleventh embodiment.
- FIG. 38 is a cross sectional view schematically showing still another example of the diffusion structure in the eleventh embodiment.
- FIG. 25 is a cross sectional view schematically showing another example of the configuration of the liquid crystal display device (including the surface light source device) which is a modification of the sixth embodiment.
- FIG. 1 is a cross-sectional view schematically showing an example of the configuration of the liquid crystal display device 100 (including the surface light source device 200) according to the first embodiment of the present invention.
- the surface light source device 200 includes a surface light-emitting light guide plate 4, a light reflection sheet 5, a light guide member 6, a first light source 8, and a second light source 9.
- the surface light source device 200 also includes components 108, 106, and 107 having the function of the light guide member 6.
- the coordinate axes of the xyz orthogonal coordinate system are shown in each figure.
- the short side direction of the display surface 1a of the liquid crystal display element (liquid crystal panel) 1 is defined as the y-axis direction (direction perpendicular to the paper on which FIG. 1 is drawn), and the length of the display surface 1a of the liquid crystal panel 1
- the side direction is the x-axis direction (left-right direction in FIG. 1), and the direction perpendicular to the xy plane, which is a plane including the x-axis and y-axis, is the z-axis direction (up-down direction in FIG. 1).
- the direction from left to right is the positive direction of the x axis (+ x axis direction), and the opposite direction is the negative direction of the x axis ( ⁇ x axis direction).
- the direction from the front of the paper surface on which FIG. 1 is drawn to the paper surface is the positive direction of the y axis (+ y axis direction), and the opposite direction is the negative direction of the y axis ( ⁇ y axis direction).
- the direction from the bottom to the top is the positive direction of the z-axis (+ z-axis direction), and the opposite direction is the negative direction of the z-axis ( ⁇ z-axis direction).
- the liquid crystal display device 100 includes a transmissive liquid crystal panel 1 and a backlight unit 200 as a surface light source device.
- the backlight unit 200 includes a first optical sheet 2, a second optical sheet 3, a surface emitting light guide plate (light guide diffusion plate) 4, a light reflecting sheet 5, a light guide member 6 as an optical path changing member, a first light source. 8 and a second light source 9. These components 1, 2, 3, 4, and 5 are arranged in the z-axis direction.
- the display surface 1a of the liquid crystal panel 1 is parallel to the xy plane.
- FIG. 2 is a block diagram schematically showing the configuration of the control system of the liquid crystal display device 100 of the first embodiment.
- the liquid crystal display device 100 includes a liquid crystal panel driving unit 12 and a light source driving unit 13.
- the liquid crystal panel driving unit 12 drives the liquid crystal panel 1.
- the light source driving unit 13 drives the first light source 8 and the second light source 9.
- the operation of the liquid crystal panel driving unit 12 and the operation of the light source driving unit 13 are controlled by the control unit 11.
- the control unit 11 performs image processing on the input video signal S0 to generate a liquid crystal panel control signal S1 and a light source control signal S2.
- the control unit 11 supplies the liquid crystal panel control signal S1 to the liquid crystal panel drive unit 12, and supplies the light source control signal S2 to the light source drive unit 13.
- the liquid crystal panel drive unit 12 drives the liquid crystal panel 1 based on the liquid crystal panel control signal S1.
- the light source driving unit 13 drives the first light source 8 and the second light source 9 based on the light source control signal S2.
- the first light source 8 emits a white first light beam 81.
- the second light source 9 emits a white second light ray 91.
- the second light ray 91 travels in the ⁇ x axis direction inside the light guide member 6. Thereafter, the second light ray 91 is reflected twice to change the traveling direction to the + x-axis direction.
- the first light beam 81 travels in the + x axis direction and enters the light guide member 6.
- the first light beam 81 is mixed with the second light beam 91 by the light guide member 6, and the first light beam 81 and the second light beam 91 enter the surface light-emitting light guide plate 4 from the light incident surface 41 a of the surface light-emitting light guide plate 4.
- the first light beam 81 and the second light beam 91 become the mixed light beam 43.
- the mixed light beam 43 is a white light beam in which the first light beam 81 and the second light beam 91 are mixed.
- the surface light source device is described as a backlight device of a liquid crystal display device.
- the mixed light beam 43 is a white light beam, but the mixed light beam 43 can be a light beam other than white light.
- the mixed light beam 43 can be a white light beam or a light beam of a color other than white, depending on the application of the apparatus.
- the light guide member 6 as the optical path changing member has a function of guiding the second light beam 91 emitted from the second light source 9 to the light incident surface 41a.
- the light guide member 6 serves to change the size of the cross section of the second light beam 91 on the light incident surface 41a, for example, the size of the cross section of the second light beam 91 is changed to the size of the cross section of the first light beam 81 on the light incident surface 41a. It is also possible to provide a role for securing the optical distance so as to approach the distance.
- both the first light beam 81 emitted from the first light source 8 and the second light beam 91 emitted from the second light source 9 are transmitted from the light incident surface 41a, which is the same side surface among the plurality of side surfaces, to the surface emitting light guide plate. 4 is incident. Note that emission refers to emitting light in a certain direction.
- a plurality of micro optical elements 42 are provided on the back surface 41 b of the surface emitting light guide plate 4.
- the micro optical element 42 is, for example, a hemispherical convex lens-shaped element protruding in the ⁇ z-axis direction from the back surface 41b.
- the micro optical element 42 converts the mixed light beam 43 into illumination light 44.
- the illumination light 44 travels in the + z axis direction.
- the illumination light 44 is emitted toward the back surface 1b of the liquid crystal panel 1.
- the illumination light 44 passes through the second optical sheet 3 and the first optical sheet 2 and is irradiated on the back surface 1 b of the liquid crystal panel 1.
- the first optical sheet 2 has a function of directing light emitted from the surface light-emitting light guide plate 4 toward the back surface 1 b of the liquid crystal panel 1.
- the second optical sheet 3 has a function of suppressing illuminance unevenness by suppressing optical influences such as fine illumination unevenness.
- the light reflecting sheet 5 is disposed on the back surface 41b side (the ⁇ z-axis direction side) of the surface light emitting light guide plate 4.
- the light reflecting sheet 5 is disposed on the surface light-emitting light guide plate 4 side (+ z-axis direction side) of the light guide member 6.
- Light emitted from the surface light-emitting light guide plate 4 in the ⁇ z-axis direction is reflected by the light reflecting sheet 5.
- the light reflected by the light reflection sheet 5 passes through the surface light-emitting light guide plate 4 and is used as illumination light 44 that irradiates the back surface 1 b of the liquid crystal panel 1.
- the light reflecting sheet 5 is, for example, a light reflecting sheet using a resin such as polyethylene terephthalate as a base material, or a light reflecting sheet obtained by depositing metal on the surface of the substrate.
- the liquid crystal layer of the liquid crystal panel 1 is arranged in parallel to the xy plane.
- the display surface 1a of the liquid crystal panel 1 has a rectangular shape. Two adjacent sides of the display surface 1a are orthogonal to each other. In FIG. 1, the short side of the liquid crystal panel 1 is parallel to the y-axis, and the long side is parallel to the x-axis.
- the liquid crystal panel driving unit 12 changes the light transmittance of the liquid crystal layer in units of pixels based on the liquid crystal panel control signal S1 received from the control unit 11.
- Each pixel is composed of, for example, three subpixels.
- the first subpixel includes a color filter that transmits only red light.
- the second subpixel includes a color filter that transmits only green light.
- the third subpixel includes a color filter that transmits only blue light.
- the control unit 11 controls the transmittance of each sub-pixel, so that the liquid crystal panel 1 creates a color image. That is, the liquid crystal panel 1 creates image light by spatially modulating the illumination light 44 incident from the surface light-emitting light guide plate 4, and emits the image light from the display surface 1a. Note that image light is light having image information.
- the control unit 11 controls the light source driving unit 13 to adjust the luminance of the second light beam 91 and the luminance of the first light beam 81.
- the control unit 11 adjusts the light emission amounts of the first light source 8 and the second light source 9 based on the video signal S0. Thereby, the power consumption of the liquid crystal display device 100 can be reduced.
- the first light source 8 is arranged to face the end surface (light incident surface) 41a on the ⁇ x-axis direction side of the surface-emitting light guide plate 4.
- the second light source 9 is arranged at a position shifted in the z-axis direction from the position of the first light source 8.
- the second light source 9 is disposed on the back surface 41b side ( ⁇ z-axis direction) of the surface light-emitting light-guiding plate 4.
- the first light source 8 has, for example, a plurality of light emitting diode (LED) elements arranged at predetermined intervals (usually at regular intervals) in the y-axis direction, and the second light source 9 is predetermined in the y-axis direction, for example. It has a plurality of LED elements arranged at intervals (usually at regular intervals).
- both the first light source 8 having one row of LED elements and the second light source having one row of LED elements so as to face the incident end face 41a of the surface emitting light guide plate 4.
- the first light source 8 and the second light source are arranged adjacent to each other, and the light sources are concentrated in one place.
- the temperature around the second light source will rise too much. Due to this temperature rise, the luminous efficiency of the LED element decreases.
- the luminous efficiency represents the efficiency of the light source, and is represented by the total luminous flux per unit power.
- the lifetime of the LED element is shortened due to the temperature rise in the vicinity. Therefore, when arranging two rows of light sources, it is desirable that the respective light sources are arranged apart from each other. Thereby, the local temperature rise (nonuniform temperature distribution) by light emission of a light source can be suppressed.
- the second light source 9 is disposed to face the end face 61a of the light guide member 6.
- the end surface 61a is an end surface of the light guide member 6 on the + x axis direction side.
- the end surface 61a is a light incident end surface.
- the light guide member 6 includes a first light guide part 62a and a second light guide part 62b.
- the 1st light guide part 62a is a rectangular parallelepiped plate-shaped part arrange
- the 2nd light guide part 62b is a plate-shaped part of the trapezoid pillar arrange
- the first light guide 62 a is disposed adjacent to the light reflecting sheet 5 on the ⁇ z-axis direction side.
- the second light guide portion 62b is disposed adjacent to the ⁇ x-axis direction side of the surface light-emitting light guide plate 4.
- the light guides 62a and 62b are, for example, plate-like members having a thickness of 2 mm.
- the light guides 62a and 62b are made of a transparent material such as acrylic resin (for example, PMMA).
- the second light ray 91 enters the light guide member 6 from the end surface 61 a of the light guide member 6.
- the second light ray 91 is totally reflected at the interface between the light guide member 6 and the air layer. Total reflection is a phenomenon in which all rays are reflected without passing through the boundary surface. Then, the second light ray 91 travels through the light guide member 6 while repeating reflection.
- the second light ray 91 reaches the end surface 61c while being repeatedly reflected.
- the end surface 61c is an end surface on the ⁇ x axis direction side of the light guide portion 62a.
- FIG. 3 is a cross-sectional view schematically showing an example of a surface-emitting light guide plate (light guide diffuser plate) and its peripheral structure in the surface light source device 200 of the first embodiment.
- the two end surfaces 61b and 61e of the light guide part 62b are formed in parallel with the yz plane.
- the end surface 61e faces the end surface 41a on the ⁇ x-axis direction side of the surface light-emitting light-guiding plate 4.
- the two end faces 61c and 61d are inclined at an angle of about 45 degrees with respect to the xy plane.
- the end face 61c of the light guide member 6 is inclined so as to reflect the second light ray 91 and change its traveling direction from the ⁇ x-axis direction to the + z-axis direction.
- the end surface 61d of the light guide member 6 is inclined so as to reflect the second light ray 91 and change the traveling direction from the + z-axis direction to the + x-axis direction.
- the second light ray 91 is incident from the end face 61a.
- the second light ray 91 repeats total reflection and reaches the end face 61c.
- the second light ray 91 is reflected by the end face 61c and proceeds in the + z-axis direction. Thereafter, the second light ray 91 is reflected by the end face 61d and changes its traveling direction from the + z-axis direction to the + x-axis direction. Thereafter, the second light ray 91 is emitted from the end surface 61 e toward the light incident surface 41 a of the surface light-emitting light guide plate 4.
- the first light beam 81 emitted from the first light source 8 enters the light guide member 6 from the end surface 61b.
- the first light beam 81 is transmitted through the light guide portion 62 b of the light guide member 6 and emitted from the end surface 61 e toward the light incident surface 41 a of the surface light-emitting light guide plate 4.
- the 1st light source 8 is arrange
- the first light source 8 is an LED element that emits a light beam having a relatively large divergence angle.
- the divergence angle is the angle at which the light beam spreads. For this reason, even if the first light sources 8 are arranged at equal intervals in the y-axis direction, the first light beam 81 overlaps and becomes linear light between the end surface 61b and the end surface 61e.
- a plurality of light beams are emitted from adjacent light sources. When these plurality of light beams are spatially overlapped, the luminance distributions of these light beams are averaged to obtain a uniform luminance distribution in the arrangement direction of the light sources.
- the light beam of the first light source 8 does not have a uniform luminance distribution with a single light source. However, when a plurality of light beams overlap, the luminance distribution is averaged. The averaged light beam has a uniform luminance distribution in the arrangement direction of the light sources and becomes linear light. Further, the first light source 8 is disposed to face the end surface 61 b of the light guide member 6. The first light beam 81 is emitted from the first light source 8 toward the end surface 61b.
- the light beam of the first light source 8 does not have a uniform luminance distribution with a single light source. However, when a plurality of light beams overlap, the luminance distribution is averaged. The averaged light beam has a uniform luminance distribution in the arrangement direction of the light sources and becomes linear light. Further, the first light source 8 is disposed to face the end surface 61 b of the light guide member 6. The first light beam 81 is emitted from the first light source 8 toward the end surface 61b.
- the end surface 61 e of the light guide member 6 is disposed to face the end surface 41 a on the ⁇ x-axis direction side of the surface light-emitting light guide plate 4.
- the white first light beam 81 and the second light beam 91 emitted from the first light source 8 and the second light source 9 are mixed inside the light guide member 6 and emitted toward the surface light emitting light guide plate 4.
- the first light beam 81 and the second light beam 91 are mixed to become white linear light.
- This white linear light is a mixed light beam 43.
- the control unit 11 can control the light source driving unit 13 to adjust the ratio between the luminance of the first light beam 81 and the luminance of the second light beam 91.
- the light guide member 6 was demonstrated as a transparent member, it is not limited to a transparent member. There are two functions required for the light guide member 6.
- the first function is a function that the light guide member 6 guides the first light beam 81 and the second light beam 91 to the surface light-emitting light guide plate 4.
- the first light beam 81 is a light beam emitted from the first light source 8.
- the second light ray 91 is a light ray emitted from the second light source.
- the second function is a function in which the light guide member 6 mixes the first light beam 81 and the second light beam 91. If it is the structure which has these two functions, the light guide member 6 may have another structure. For example, the same effect can be obtained by providing a reflective film on the end faces 61c and 61d.
- the reflective film can be realized by evaporating a highly reflective metal such as aluminum, silver or gold on the end face.
- FIG. 4 is a cross-sectional view schematically showing another example of the surface-emitting light guide plate 4 and its peripheral structure in the surface light source device 200 of the first embodiment.
- the light guide member 108 is composed of three components, reflecting members 181, 182, and 183.
- the reflecting surfaces 181a, 182a, 183a of the reflecting members 181, 182 and 183 are mirror surfaces.
- the reflecting member 181 and the reflecting member 182 are shown as separate parts, both ends in the y-axis direction can be connected to form a hollow one part.
- the light guide member 183 can be configured such that a part of the structural member is a mirror surface.
- the surface emitting light guide plate 4 is arranged in parallel to the display surface 1 a of the liquid crystal panel 1.
- the surface light-emitting light guide plate 4 has a micro optical element 42 on the back surface.
- the back surface is a surface on the opposite side to the liquid crystal panel 1 and is a surface on the ⁇ z-axis direction side of the surface light-emitting light-guiding plate 4.
- the micro optical element 42 changes the mixed light beam 43 into illumination light 44.
- the mixed light beam 43 is light that propagates inside the surface emitting light guide plate 4.
- the illumination light 44 is light emitted in the + z axis direction.
- the illumination light 44 is emitted from the surface light-emitting light guide plate 4 toward the back surface 1 b of the liquid crystal panel 1.
- FIG. 5 is a diagram schematically showing an example of the arrangement of the micro optical elements 42 provided on the surface light-emitting light guide plate 4 in the surface light source device 200 of the first embodiment.
- the surface emitting light guide plate 4 is a component made of a transparent material such as acrylic resin (for example, PMMA).
- the surface-emitting light guide plate 4 is a plate-like member having a thickness of 4 mm, for example.
- the surface emitting light guide plate 4 has a micro optical element 42 on the back surface 41b.
- the micro optical element 42 has a hemispherical convex shape protruding in the ⁇ z-axis direction.
- this hemispherical convex shape is referred to as a convex lens shape.
- the mixed light beam 43 is incident from the end surface 41a of the surface light-emitting light guide plate 4.
- the mixed light beam 43 is totally reflected at the interface between the surface emitting light guide plate 4 and the air layer.
- the mixed light beam 43 propagates inside the light guide pair 4.
- the mixed light beam 43 travels in the + x-axis direction while repeating reflection.
- the mixed light beam 43 enters the micro optical element 42, it is reflected by the curved surface of the micro optical element 42 and changes the traveling direction.
- the traveling direction of the mixed light beam 43 changes, there is a light beam in the mixed light beam 43 that does not satisfy the total reflection condition at the interface between the surface of the surface emitting light guide plate 4 and the air layer.
- the light beam When the light beam does not satisfy the total reflection condition, the light beam is emitted from the surface of the surface light-emitting light guide plate 4 toward the back surface 1 b of the liquid crystal panel 1.
- the surface of the surface light-emitting light guide plate 4 is a surface on the liquid crystal panel 1 side.
- the arrangement density of the micro optical elements 42 changes at a position in the xy plane on the surface light-emitting light guide plate 4.
- the arrangement density is the number of the micro optical elements 42 per unit area, the size of the micro optical elements 42, or the like.
- the in-plane luminance distribution of the illumination light 44 can be controlled by changing the arrangement density of the micro optical elements 42.
- the illumination light 44 is light emitted from the surface emitting light guide plate 4.
- the in-plane luminance distribution is a distribution indicating the level of luminance with respect to a position expressed in two dimensions on an arbitrary plane.
- the in-plane here refers to the display surface.
- the arrangement density of the micro optical elements 42 changes with respect to the position of the mixed light beam 43 in the traveling direction.
- the traveling direction of the mixed light beam 43 is the + x-axis direction in FIG.
- the surface light-emitting light guide plate 4 has a micro optical element 42 in a region from the vicinity of the end surface 41a to the end surface 41c.
- the end surface 41c is an end surface facing the end surface 41a.
- the arrangement density continuously changes from sparse to dense from the vicinity of the end face 41a toward the end face 41c.
- the micro optical element 42 has a convex lens shape.
- the curvature of the surface is about 0.15 mm.
- the maximum height of the micro optical element 42 is about 0.005 mm.
- the refractive index of the micro optical element 42 is about 1.49.
- the material of the surface emitting light guide plate 4 and the micro optical element 42 can be acrylic resin.
- the material of the surface light-emitting light guide plate 4 and the micro optical element 42 is not limited to acrylic resin, and other resin materials (for example, polycarbonate resin) having good light transmittance and excellent moldability, or glass Can be a material.
- the thickness of the surface emitting light guide plate 4 is not limited to 4 mm. From the viewpoint of reducing the thickness and weight of the liquid crystal display device 100, it is desirable to use the surface emitting light guide plate 4 having a small thickness.
- the micro optical element 42 has a convex lens shape.
- the shape of the micro optical element 42 is not limited to the convex lens shape.
- the function necessary for the micro optical element 42 is that the micro optical element 42 reflects the mixed light beam 43 in the + z-axis direction and emits the mixed light beam 43 toward the back surface 1 b of the liquid crystal panel 1.
- the mixed light beam 43 is light that travels in the x-axis direction inside the surface emitting light guide plate 4. If it has this function, the micro optical element 42 may have a different shape. For example, a prism shape or a random uneven pattern has the same function.
- the illumination light 44 is light emitted from the surface light-emitting light guide plate 4 toward the liquid crystal panel 1.
- the illumination light 44 may be reflected by the first optical sheet 2 and the second optical sheet 3 and travel in the ⁇ z-axis direction.
- the liquid crystal display device 100 according to Embodiment 1 includes the light reflecting sheet 5 on the ⁇ z-axis direction side of the surface-emitting light-guiding plate 4.
- the light reflecting sheet 5 directs the reflected light traveling in the ⁇ z-axis direction again in the + z-axis direction. Thereby, the liquid crystal display device 100 can utilize light efficiently.
- the liquid crystal display device 100 has light sources using white LED elements at two locations.
- the two places are the side surface of the surface light-emitting light guide plate 4 and the back surface of the surface light-emitting light guide plate 4.
- the liquid crystal display device 100 can suppress the increase in thickness (dimension in the z-axis direction) and increase the number of light sources.
- the size of the backlight unit 200 is suppressed with respect to the display area of the liquid crystal display device 100, and the liquid crystal display device 100 can achieve high brightness and thinness.
- the display area is an area for displaying an effective image.
- the display area is an area that expands in the x-axis direction and the y-axis direction in terms of coordinates.
- the light sources are arranged on the side surface and the back surface of the surface light-emitting light guide plate 4, it is possible to mitigate the increase in ambient temperature due to the heat generated by each light source. Thereby, the fall of the luminous efficiency of the light source by ambient temperature rise can be suppressed. Moreover, the lifetime of the 1st light source 8 and the 2nd light source 9 can be lengthened.
- the backlight unit 200 can generate the illumination light 44 having a uniform luminance distribution.
- the luminance distribution of the illumination light 44 is uniform within the display surface. Therefore, it is possible to provide the liquid crystal display device 100 that can display a good image with reduced luminance unevenness.
- the light propagation distance is the distance that light travels. The propagation of light means that light travels and travels.
- the liquid crystal display device 100 of the first embodiment has one light guide member 6.
- the first light beam 81 and the second light beam 91 emitted from the first light source 8 and the second light source 9 enter the light guide member 6 from different end surfaces 61a and 61b.
- the light guide member 6 does not need to be configured by one member.
- the light guide member 6 may be configured as shown in FIGS. 6 and 7.
- FIG. 6 is a cross-sectional view schematically showing another example of the surface emitting light guide plate and its peripheral structure in the surface light source device 200 of the first embodiment.
- FIG. 6 shows a light guide member composed of two parts.
- the backlight unit 200 includes a first light guide member 106 and a second light guide member 107.
- the second light ray 91 enters the light guide member 106 from the end face 161a.
- the second light ray 91 travels in the ⁇ x axis direction inside the first light guide member 106.
- the second light ray 91 is reflected by the end face 161c and proceeds in the + z-axis direction.
- the second light ray 91 is emitted from the end face 161b.
- the second light beam 91 enters the second light guide member 107 from the end surface 171 a of the second light guide member 107.
- the second light ray 91 travels in the + z-axis direction inside the second light guide member 107.
- the second light ray 91 is reflected by the end face 171c and proceeds in the + x-axis direction.
- the first light beam 81 is incident from the end surface 171 b of the second light guide member 107.
- the first light beam 81 travels in the + x-axis direction inside the second light guide member 107.
- the first light beam 81 is emitted from the end surface 171d.
- the second light guide unit 107 has an end surface 171 a near the incident position of the first light beam 81. After the first light beam 81 is incident on the second light guide member 107, the first light beam 81 is totally reflected at the interface between the air layer and the end surface 171a. For this reason, the 1st light ray 81 can advance toward the surface emitting light-guide plate 4 efficiently.
- FIG. 7 is a cross-sectional view schematically showing still another example of the surface-emitting light guide plate and its peripheral structure in the surface light source device 200 of the first embodiment.
- FIG. 7 shows a configuration in which a part of the function of the light guide member 6 is provided to the surface light-emitting light guide plate 400.
- the end portion of the light guide member 106 on the ⁇ x axis direction side protrudes in the ⁇ x axis direction from the end portion of the reflection sheet 5 on the ⁇ x axis direction side.
- An end portion on the ⁇ x-axis direction side of the surface light-emitting light guide plate 400 protrudes in the ⁇ x-axis direction from an end portion on the ⁇ x-axis direction side of the reflection sheet 5.
- the second light ray 91 is incident on the light guide member 106 from the end face 161a.
- the second light ray 91 travels in the ⁇ x axis direction inside the first light guide member 106.
- the second light ray 91 is reflected by the end face 161c and proceeds in the + z-axis direction.
- the second light ray 91 is emitted from the end face 161b. Thereafter, the second light ray 91 enters the inside of the surface emitting light guide plate 400 from the back surface of the surface emitting light guide plate 400.
- the second light ray 91 travels in the + z-axis direction inside the surface emitting light guide plate 400.
- the second light ray 91 is reflected by the end surface 141d and travels in the + x-axis direction.
- the first light beam 81 is incident from the end surface 141 a of the surface emitting light guide plate 400.
- the first light beam 81 travels in the + x-axis direction inside the surface emitting light guide plate 400.
- the second light ray 91 enters the surface light-emitting light guide plate 400 from the back surface 141b close to the end surface 141a on which the first light beam 81 is incident.
- the end portion 145 is a range including the end surface 141a and the back surface 141b close to the end surface 141a.
- the light use efficiency is the ratio of the amount of light used for image display to the amount of light emitted from the light source.
- the first light beam 81 and the second light beam 91 emitted from the two first light sources 8 and second light sources 9 arranged at different positions are the surface emitting light guide plates. 4 is incident from the short end face 41a.
- the long end face of the surface light-emitting light guide plate 4 can be used as the incident surface.
- the long end face is an end face parallel to the xz plane in FIGS. 1, 6, and 7.
- FIG. 8 is a cross-sectional view schematically showing an example of the configuration of the liquid crystal display device 101 (including the surface light source device 201) of the second embodiment.
- the surface light source device 201 includes a surface emitting light guide plate 4, a light reflection sheet 5, a light guide member 6, a first light source 208, and a second light source 209.
- the surface light source device 201 also includes a component having the function of the light guide member 6. 8, components that are the same as or correspond to the components shown in FIG. 1 (Embodiment 1) are assigned the same reference numerals.
- the liquid crystal display device 101 is a transmissive display device.
- the liquid crystal display device 101 includes a first light source 208 and a second light source 209 of different colors instead of the white first light source 8 and the second light source 9 of the liquid crystal display device 100 of the first embodiment.
- the liquid crystal display device 101 is the same as that of the first embodiment except for the above differences. Also in the second embodiment, the forms of FIGS. 4, 6, and 7 other than the form of FIG.
- the width of the transmission wavelength band of the color filter of the liquid crystal panel must be set narrow.
- the amount of light transmitted through the color filter decreases.
- fluorescent lamps that have been used conventionally have an emission spectrum peak in the red region in the orange wavelength region.
- a white LED element using a yellow phosphor also has an emission spectrum peak in the red region in the orange wavelength region. That is, the wavelength peak in the red region is in an orange region that is shifted from the red region.
- the color purity is to be increased in red, the amount of light transmitted through the color filter is extremely reduced, and the luminance is significantly reduced.
- the liquid crystal display device 101 has an LED element that emits a blue-green first light beam 281 to the first light source 208.
- the blue-green first light beam 281 is a mixture of blue light and green light.
- the liquid crystal display device 101 uses a single-color LED element that emits a red second light beam 291 as the second light source 209.
- the light of a single color LED element has a narrow wavelength width. That is, the light of a single color LED element has high color purity. For this reason, the color purity of red is improved by using a red light LED element. That is, the liquid crystal display device 101 can expand the color reproduction range of the display color.
- a single color is light consisting only of a certain wavelength. Color purity represents the height of single color.
- FIG. 9 is a block diagram schematically showing the configuration of the control system of the liquid crystal display device 101 of the second embodiment.
- the liquid crystal display device 101 has the same configuration as that of the liquid crystal display device 100 shown in FIG.
- the liquid crystal display device 101 includes a liquid crystal panel driving unit 12 and a light source driving unit 13.
- the liquid crystal panel driving unit 12 drives the liquid crystal panel 1.
- the light source driving unit 13 drives the first light source and the second light source. Note that the first light source is the first light source 208, and the second light source is the second light source 209.
- the control unit 11 controls the operation of the liquid crystal panel driving unit 12 and controls the operation of the light source driving unit 13.
- the controller 11 performs image processing on the input video signal S10 to generate a liquid crystal panel control signal S11 and a light source control signal S12.
- the control unit 11 supplies the liquid crystal panel control signal S11 to the liquid crystal panel driving unit 12. Further, the control unit 11 supplies a light source control signal S12 to the light source driving unit 13.
- the liquid crystal panel drive unit 12 drives the liquid crystal panel 1 based on the liquid crystal panel control signal.
- the light source driving unit 13 drives the first light source 208 and the second light source 209 based on the light source control signal S12.
- the second light source 209 emits a red second light beam 291.
- the second light ray 291 travels in the light guide member 6 in the ⁇ x axis direction. Thereafter, the second light beam 291 is reflected twice and changes the traveling direction in the + x-axis direction.
- the second light ray 291 is reflected by the end face 61c and the end face 61d.
- the first light source 208 emits a blue-green first light beam 281.
- the first light ray 281 travels in the + x axis direction.
- the first light beam 281 is incident on the light guide member 6.
- the first light beam 281 is mixed with the second light beam 291 in the light guide member 6. Thereafter, the first light beam 281 enters the surface-emitting light guide plate 4.
- the first light beam 281 and the second light beam 291 are mixed into a light beam 243.
- Blue-green is a color having peak luminance in blue and green.
- the surface-emitting light guide plate 4 has a micro optical element 42 on the surface in the ⁇ z-axis direction side (the lower side in FIG. 8).
- the micro optical element 42 converts the light beam 243 into illumination light 244.
- the illumination light 244 travels in the + z axis direction.
- the illumination light 244 is emitted toward the back surface 1b of the liquid crystal panel 1.
- the illumination light 244 passes through the second optical sheet 3 and the first optical sheet 2. Thereafter, the illumination light 244 is irradiated toward the back surface 1 b of the liquid crystal panel 1.
- the control unit 11 can adjust the luminance of the second light beam 291 and the luminance of the first light beam 281 by controlling the light source driving unit 13. That is, the ratio between the luminance of the second light beam 291 and the luminance of the first light beam 281 can be adjusted.
- the second light beam 291 is red light emitted from the second light source 209.
- the first light beam 281 is blue-green light emitted from the first light source 208.
- the control unit 11 adjusts the light emission amount of each light source based on the video signal. That is, the control unit 11 adjusts the luminance ratio of each light source based on the video signal. Thereby, the power consumption of the liquid crystal display device 101 can be reduced.
- the second light source 209 is disposed so as to face the end surface 61 a of the light guide member 6.
- the end surface 61a is an end surface of the light guide member 6 on the + x axis direction side.
- the end face 61a is a light incident end face.
- the light guide member 6 is disposed in parallel to the display surface 1 a of the liquid crystal panel 1.
- the second light source 209 includes a plurality of LED elements arranged at equal intervals in the y-axis direction.
- the second light source 209 emits a red light beam. This spectrum of red light has a peak in the vicinity of 640 nm.
- the second light source 209 is a point light source having directivity.
- the second light beam 291 emitted from the second light source 209 enters the light guide member 6.
- the second light ray 291 is totally reflected at the interface between the light guide member 6 and the air layer. Then, the second light ray 291 travels inside the light guide member 6 while being repeatedly reflected.
- the distance traveled by the second light beam 291 is a predetermined optical distance.
- the second light ray 291 reaches the end surface 61c while repeating reflection.
- the second light ray 291 spreads depending on its divergence angle. For this reason, the second light beam 291 overlaps the light beam of another adjacent LED element while traveling a predetermined optical distance.
- the light rays overlap and become linear light with a uniform luminance distribution in the y-axis direction.
- the second light beam 291 Since the light beams of adjacent LED elements overlap each other, the second light beam 291 needs to travel a predetermined optical distance.
- the predetermined optical distance is determined by the divergence angle of the LED elements and the arrangement interval of the LED elements.
- the second light beam 291 spreads in the LED element arrangement direction inside the light guide member 6 according to its divergence angle.
- the second light beam 291 needs a distance to be sufficiently spread in order to generate linear light. This distance is a predetermined optical distance.
- the arrangement direction of the LED elements is the y-axis direction in FIG.
- the distance from the end surface 61a to the end surface 61c of the light guide member 6 is set to a length equal to or longer than a predetermined optical distance.
- a plurality of second light rays 291 emitted from the second light source 209 are linear light sources having a uniform luminance distribution.
- the second light ray 291 enters from the end face 61a. And the 2nd light ray 291 repeats total reflection and reaches the end surface 61c. The second light ray 291 is reflected by the end face 61c and travels in the + z-axis direction. Thereafter, the second light ray 291 is reflected by the end face 61d and changes its traveling direction from the + z-axis direction to the + x-axis direction. Thereafter, the second light beam 291 exits from the end surface 61 e toward the surface light-emitting light guide plate 4.
- the first light beam 281 emitted from the first light source 208 enters the light guide member 6 from the end surface 61b.
- the first light beam 281 passes through the light guide portion 62 b of the light guide member 6 and exits from the end surface 61 e toward the surface light-emitting light guide plate 4.
- the 1st light source 208 is arrange
- the first light source 208 is an LED element that emits a light beam having a relatively large divergence angle. For this reason, even if the first light sources 208 are arranged at equal intervals in the y-axis direction, the first light beam 281 overlaps and becomes linear light between the end surface 61b and the end surface 61e. A plurality of light beams are emitted from adjacent light sources. When these plurality of light beams are spatially overlapped, the luminance distributions of these light beams are averaged to obtain a uniform luminance distribution in the arrangement direction of the light sources. Further, the first light source 208 is disposed to face the end surface 61 b of the light guide member 6. The first light beam 281 is emitted from the first light source 208. Thereafter, the first light beam 281 travels toward the end surface 61b.
- the blue-green first light beam 281 is emitted from the first light source 208.
- the first light beam 281 is mixed with the red second light beam 291 emitted from the second light source 209 to become a white light beam 243.
- the first light ray 281 has peaks at around 450 nm and around 530 nm.
- the first light beam 281 is blue-green light having a continuous spectrum in a band from 420 nm to 580 nm.
- the first light source 208 can be a light source that emits blue light and green light.
- the light source has a combination of an excitation light source and a phosphor.
- the first light source 208 can be a light source having a phosphor that emits blue light and green light by ultraviolet light.
- the light source emits blue light and green light by the ultraviolet light exciting the phosphor.
- the first light source 208 may be a light source that emits blue light and green light by exciting blue phosphors with blue light.
- a method of arranging the two rows of the first light source 208 and the second light source 209 for example, a method of arranging the two rows of the first light source 208 and the second light source 209 along the incident end surface 41a of the surface light-emitting light guide plate 4 is considered. It is done. However, the arrangement of two rows of light sources adjacent to each other is to collect the light sources in one place. Two rows of light sources are arranged adjacent to each other, and the light sources are gathered in one place, so that the temperature around the light sources rises due to the heat generated by each LED element. The luminous efficiency of the LED element decreases due to the temperature increase around this area. In addition, the lifetime of the LED element is shortened due to the temperature rise in the vicinity.
- the respective light sources are arranged apart from each other. Therefore, it can suppress that ambient temperature rises by light emission of a light source. In addition, the lifetimes of the first light source 208 and the second light source 209 can be extended.
- the end surface 61e of the light guide member 6 is opposed to the end surface 41a on the -x axis direction side of the surface light-emitting light guide plate 4.
- a blue-green first light beam 281 is emitted from the first light source 208.
- the second red light beam 291 is emitted from the second light source 209.
- the blue-green first light beam 281 and the red second light beam 291 are mixed inside the light guide member 6.
- the first light beam 281 and the second light beam 291 become white linear light.
- the first light beam 281 and the second light beam 291 are emitted from the end surface 61 e toward the surface light-emitting light guide plate 4.
- the light beam 243 is white linear light.
- the control unit 11 can control the light source driving unit 13 to adjust the ratio of the luminance of the first light beam 281 and the luminance of the second light beam 291 to generate white linear light.
- the light guide member 6 has been described as a transparent member having a thickness of 2 mm, but is not limited to a transparent member having a thickness of 2 mm.
- the first function is a function that the light guide member 6 guides the first light beam 281 and the second light beam 291 to the surface emitting light guide plate 4.
- the first light beam 281 is a light beam emitted from the first light source 208.
- the second light beam 291 is a light beam emitted from the second light source 209.
- the second function is a function that the light guide member 6 mixes the first light beam 281 and the second light beam 291. If it is the structure which has these two functions, the light guide member 6 may have another structure. For example, the same effect can be obtained by providing a reflective film on the end faces 61c and 61d.
- the light guide member 6 can take the same form as that of FIG. 4 of the first embodiment.
- the light guide member 108 shown in FIG. 4 is composed of three parts, reflecting members 181, 182, and 183.
- the reflecting surfaces 181a, 182a, 183a of the reflecting members 181, 182 and 183 are mirror surfaces.
- the reflecting member 181 and the reflecting member 182 are shown as separate parts, both ends in the y-axis direction can be connected to form a hollow one part.
- the light guide member 183 can be configured such that a part of the structural member is a mirror surface.
- the liquid crystal display device 101 is considered to be thin.
- the liquid crystal display device 101 can be reduced in weight. Therefore, it is desirable to use a thin light guide member.
- the thickness is reduced, the rigidity of the light guide member 6 is reduced. For this reason, it is necessary to consider problems such as a decrease in rigidity of the light guide member 6.
- the surface emitting light guide plate 4 is arranged in parallel to the display surface 1 a of the liquid crystal panel 1.
- the surface light-emitting light guide plate 4 has a micro optical element 42 on the back surface.
- the back surface is a surface opposite to the liquid crystal panel 1 and is a surface on the side in the ⁇ z-axis direction.
- the light beam 243 is light that travels inside the surface emitting light guide plate 4.
- the illumination light 244 is light emitted in the + z-axis direction.
- the micro optical element 42 changes the light beam 243 into illumination light 244.
- the illumination light 244 is emitted from the surface light-emitting light guide plate 4 toward the back surface 1 b of the liquid crystal panel 1.
- the light beam 243 is incident from the end surface 41a of the surface light-emitting light guide plate 4.
- the light beam 243 is totally reflected at the interface between the surface emitting light guide plate 4 and the air layer.
- the light beam 243 propagates through the light guide pair 4 while repeating reflection.
- the light beam 243 travels in the + x-axis direction while repeating reflection.
- the traveling direction of the light beam 243 changes, some of the light beams 243 do not satisfy the total reflection condition at the interface between the surface of the surface light-emitting light guide plate 4 and the air layer.
- the light beam When the light beam does not satisfy the total reflection condition, the light beam is emitted from the surface of the surface light-emitting light guide plate 4 toward the back surface 1 b of the liquid crystal panel 1.
- the surface of the surface light-emitting light guide plate 4 is a surface on the liquid crystal panel 1 side.
- the arrangement density of the micro optical elements 42 changes at a position in the xy plane on the surface light-emitting light guide plate 4.
- the arrangement density is the number of the micro optical elements 42 per unit area, the size of the micro optical elements 42, or the like.
- the in-plane luminance distribution of the illumination light 244 can be controlled by changing the arrangement density of the micro optical elements 42.
- the illumination light 244 is light emitted from the surface emitting light guide plate 4.
- the in-plane luminance distribution is a distribution indicating the level of luminance with respect to a position expressed in two dimensions on an arbitrary plane.
- the in-plane here refers to the display surface.
- the arrangement density of the micro optical elements 42 changes with respect to the position of the light beam 243 in the traveling direction.
- the traveling direction of the light beam 243 is the + x-axis direction in FIG.
- the surface light-emitting light guide plate 4 has a micro optical element 42 in a region from the vicinity of the end surface 41a to the end surface 41c.
- the end surface 41c is an end surface facing the end surface 41a.
- the arrangement density continuously changes from sparse to dense from the vicinity of the end face 41a toward the end face 41c.
- the micro optical element 42 has a convex lens shape.
- the shape of the micro optical element 42 is not limited to the convex lens shape.
- the function necessary for the micro optical element 42 is that the micro optical element 42 reflects the light beam 243 in the + z-axis direction and emits the light beam 243 toward the back surface 1 b of the liquid crystal panel 1.
- the light beam 243 is light traveling in the x-axis direction inside the surface emitting light guide plate 4. If it has this function, the micro optical element 42 may have a different shape. For example, a prism shape or a random uneven pattern has the same function.
- the illumination light 244 is light emitted from the surface emitting light guide plate 4 toward the liquid crystal panel 1.
- the illumination light 244 may be reflected by the first optical sheet 2 and the second optical sheet 3 and travel in the ⁇ z-axis direction.
- the liquid crystal display device 101 according to the second embodiment includes a light reflection sheet 5 on the ⁇ z-axis direction side of the surface-emitting light guide plate 4.
- the light reflecting sheet 5 directs the reflected light traveling in the ⁇ z-axis direction again in the + z-axis direction. Thereby, the liquid crystal display device 101 can use light efficiently.
- the liquid crystal display device 101 of Embodiment 2 has light sources using LED elements at two locations.
- the two places are the side surface of the surface light-emitting light guide plate 4 and the back surface of the surface light-emitting light guide plate 4.
- the liquid crystal display device 101 can suppress the increase in thickness (dimension in the z-axis direction) and increase the number of light sources.
- the size of the backlight unit 201 is suppressed with respect to the display area of the liquid crystal display device 101, and the liquid crystal display device 101 can achieve high brightness and thinness.
- the display area is an area for displaying an effective image.
- the display area is an area that expands in the x-axis direction and the y-axis direction in terms of coordinates.
- the light sources are arranged on the side surface and the back surface of the surface light-emitting light guide plate 4, it is possible to mitigate the increase in ambient temperature due to the heat generated by each light source. Thereby, the fall of the luminous efficiency of the light source by ambient temperature rise can be suppressed. In addition, the lifetimes of the first light source 208 and the second light source 209 can be extended.
- the backlight unit 201 can have a sufficient light propagation distance. For this reason, the backlight unit 201 can generate the illumination light 244 having a uniform luminance distribution. The luminance distribution of the illumination light 244 is uniform within the display surface. Therefore, it is possible to provide the liquid crystal display device 101 that can display a good image with reduced luminance unevenness.
- the second light source 209 of the liquid crystal display device 101 emits red light.
- the first light source 208 of the liquid crystal display device 101 emits blue-green light.
- Blue-green is a color obtained by mixing blue and green.
- conventionally used fluorescent lamps have the emission spectrum peak in the red region in the orange wavelength region.
- a white LED element using a yellow phosphor also has an emission spectrum peak in the red region in the orange wavelength region. That is, the wavelength peak in the red region is in an orange region that is shifted from the red region.
- the color purity is to be increased in red, the amount of transmitted light is extremely reduced and the luminance is significantly reduced.
- By replacing the fluorescent lamp and the white LED element with a red LED element it is possible to suppress a decrease in the amount of transmitted light of the color filter. Further, the effect of improving the color purity can be obtained.
- a red LED element having a peak wavelength at 640 nm is used for the second light source 209.
- the present invention is not limited to this.
- a red LED element having a wavelength peak different from 640 nm can be used.
- an LED element that emits blue or green light can be used.
- the light from the first light source 208 needs to be mixed with the light from the second light source 209 to become white light. That is, the light from the first light source 208 is complementary to the light from the second light source 209.
- the number of LED elements constituting the first light source 208 and the second light source 209 may be different.
- the arrangement interval of LED elements of a light source having a large number of LED elements is narrow.
- interval of the LED element of a light source with few LED elements is wide.
- a light source with a small number of LED elements needs a longer optical distance. This is because the light emitted from each LED element needs to overlap.
- the divergence angles of the LED elements constituting the first light source 208 and the second light source 209 may be different.
- a light source having a small divergence angle of the LED element needs a longer optical distance. This is because the light emitted from each LED element needs to overlap.
- the optical distance for superimposing the light is different.
- the liquid crystal display device 101 can obtain a sufficient optical distance through which light propagates.
- the liquid crystal display device 101 can obtain linear light with a uniform luminance distribution.
- the second light source 209 needs to select a light source having a small number of LED elements.
- the second light source 209 needs to select a light source having a narrow divergence angle of the LED element.
- a white fluorescent lamp or a white LED element is used as a light source.
- the transmission wavelength of the color filter of the liquid crystal panel 1 is set to be narrow. In this case, the luminance of the image decreases as the light loss due to the color filter increases.
- the liquid crystal display device 101 according to the second embodiment uses single-color LED elements. Single color light has high color purity. By using a single color LED element, the color purity of red is improved. The liquid crystal display device 101 can widen the color reproduction range of display colors. Further, by improving the red color purity, the liquid crystal display device 101 can reduce light loss due to the color filter. For this reason, the liquid crystal display device 101 can suppress a decrease in brightness. Despite the low power consumption, the liquid crystal display device 101 can realize a wide color gamut with high brightness.
- the liquid crystal display device 101 of Embodiment 2 has one light guide member 6.
- the light guide member 6 does not need to be configured by one member.
- the light guide member 6 may be configured as shown in FIG. 6 or FIG.
- the liquid crystal display device 101 has a configuration in which light emitted from two light sources arranged at different positions is incident from the short end face of the surface light-emitting light-guiding plate 4.
- the long end face of the surface light-emitting light guide plate 4 can be used as the incident surface.
- the long end face is an end face parallel to the xz plane in FIG.
- the light source driving unit individually controls the outputs of the first light source 208 and the second light source 209 based on the image signal, thereby reducing power consumption and reducing stray light to improve contrast. be able to. This is because the light unnecessary for display can be extinguished by controlling the first light source 208 and the second light source 209 separately. Further, the output of light unnecessary for display can be reduced. Thus, stray light can be reduced by reducing unnecessary light. Stray light is light that travels outside the normal optical path in an optical device, and is harmful to image formation.
- FIG. 10 is a cross-sectional view schematically showing an example of the configuration of the liquid crystal display device 102 (including the surface light source device 202) according to the third embodiment.
- the surface light source device 202 includes a surface-emitting light guide plate 4, a light reflection sheet 5, a light guide member 6, a first light source 208, and a second light source 209. Further, the surface light source device 202 includes a component having the function of the light guide member 6. 10, components that are the same as or correspond to the components shown in FIG. 8 (Embodiment 2) are assigned the same reference numerals.
- the liquid crystal display device 102 is a transmissive display device.
- the second light source 209 in the second embodiment has an LED element, but the second light source 309 in the third embodiment has a laser light emitting element.
- the liquid crystal display device 102 is the same as that of the second embodiment except for the above differences.
- the third embodiment is different from the first embodiment in the components of the first light source 208 and the second light source 309, and the other components are the same. Also in the third embodiment, the modes of FIGS. 4, 6, and 7 other than the mode of FIG. 1 of the first embodiment can be taken.
- the width of the transmission wavelength band of the color filter of the liquid crystal panel must be set narrow.
- the width of the transmission wavelength band is set narrow, the amount of light transmitted through the color filter decreases. For this reason, when the color purity of the display color is to be increased, there arises a problem that the luminance is lowered due to a decrease in the amount of light transmitted through the color filter.
- the color purity is improved by using a laser light emitting element having a narrow wavelength region instead of the LED element. This is because the wavelength region of the laser light emitting element is narrower than that of a single color LED element.
- the surface light source device 202 which is a backlight unit can reduce the loss of light. Further, the backlight unit 202 can suppress a decrease in brightness. Therefore, the backlight unit 202 has low power consumption and can improve color purity. Further, since the laser light emitting element has high directivity, the coupling efficiency between the light guide member 6 and the surface light emitting light guide plate 4 is improved.
- the first light source 208 uses an LED element that emits a blue-green first light beam 281. Blue-green light is light obtained by mixing blue light and green light.
- the second light source 309 uses a laser light emitting element that emits a red second light beam 391.
- the wavelength width of the laser beam is narrow. That is, the laser beam has high color purity. For this reason, the red color purity is improved by using a laser emitting element of red light. That is, the color reproduction range of the display color is widened.
- FIG. 11 is a block diagram schematically showing the configuration of the control system of the liquid crystal display device 102 of the third embodiment.
- the liquid crystal display device 102 includes a liquid crystal panel driving unit 12 and a light source driving unit 13.
- the liquid crystal panel drive unit 12 drives the liquid crystal panel 1.
- the light source driving unit 13 drives the first light source and the second light source.
- the first light source is the first light source 208.
- the second light source is a laser light source 309.
- the control unit 11 controls the operation of the liquid crystal panel driving unit 12 and controls the operation of the light source driving unit 13.
- the controller 11 performs image processing on the input video signal S20 to generate a liquid crystal panel control signal S21 and a light source control signal S22.
- the control unit 11 supplies the liquid crystal panel control signal S21 to the liquid crystal panel driving unit 12. Further, the control unit 11 supplies the light source control signal S22 to the light source driving unit 13.
- the liquid crystal panel drive unit 12 drives the liquid crystal panel 1 based on the liquid crystal panel control signal S21.
- the light source driving unit 13 drives the first light source 208 and the second light source 309 based on the light source control signal S22.
- the second light source 309 emits a red second light ray 391.
- the second light ray 391 is incident from the end surface 61 a of the light guide member 6.
- the second light ray 391 travels in the ⁇ x axis direction inside the light guide member 6. Thereafter, the second light ray 391 is reflected twice to change the traveling direction in the + x-axis direction.
- the second light ray 391 is reflected by the end surface 61c and the end surface 61d.
- the first light source 208 emits a blue-green first light beam 281. Blue-green is a color having peak luminance in blue and green.
- the first light ray 281 travels in the + x axis direction.
- the first light beam 281 enters the light guide part 62 b of the light guide member 6.
- the first light beam 281 is mixed with the second light beam 391 in the light guide portion 62 b of the light guide member 6.
- the first light beam 281 enters the surface-emitting light guide plate 4.
- the first light beam 281 and the second light beam 391 are mixed into a light beam 343.
- the surface-emitting light guide plate 4 has a micro optical element 42 on the surface in the ⁇ z-axis direction side (the lower side in FIG. 11).
- the micro optical element 42 converts the light beam 343 into illumination light 344.
- the illumination light 344 travels in the + z axis direction.
- the illumination light 344 is emitted toward the back surface 1b of the liquid crystal panel 1.
- the illumination light 344 passes through the second optical sheet 3 and the first optical sheet 2. Thereafter, the illumination light 344 is irradiated toward the back surface 1 b of the liquid crystal panel 1.
- the optical sheet has a function of directing the traveling direction of light emitted from the surface light-emitting light guide plate 4 toward the back surface 1b of the liquid crystal panel.
- the second optical sheet 3 has a function of suppressing optical influences such as fine illumination unevenness.
- the light reflecting sheet 5 is disposed on the ⁇ z-axis direction side of the surface emitting light guide plate 4.
- the light reflecting sheet 5 is disposed on the light guide member 6 on the + z axis direction side.
- Light emitted from the surface light-emitting light guide plate 4 in the ⁇ z-axis direction is reflected by the light reflecting sheet 5.
- the light reflected by the light reflecting sheet 5 is used as illumination light 344 that irradiates the back surface 1 b of the liquid crystal panel 1.
- the light reflecting sheet 5 for example, a light reflecting sheet based on a resin such as polyethylene terephthalate can be adopted.
- the light reflection sheet 5 can employ a light reflection sheet in which a metal is deposited on the surface of the substrate.
- the liquid crystal layer of the liquid crystal panel 1 is arranged in parallel to the xy plane.
- the display surface 1a of the liquid crystal panel 1 has a rectangular shape. Two adjacent sides of the display surface 1a are orthogonal to each other. The short side is parallel to the y-axis. The long side is parallel to the x-axis.
- the liquid crystal panel driving unit 12 changes the light transmittance of the liquid crystal layer in units of pixels based on the liquid crystal panel control signal received from the control unit 11.
- Each pixel is further composed of three sub-pixels.
- the first subpixel includes a color filter that transmits only red light.
- the second subpixel includes a color filter that transmits only green light.
- the third subpixel includes a color filter that transmits only blue light.
- the control unit 11 controls the transmittance of each sub-pixel, so that the liquid crystal panel 1 creates a color image. That is, the liquid crystal panel 1 creates image light by spatially modulating the illumination light 344 incident from the surface light-emitting light guide plate 4. This image light is emitted from the display surface 1a. Note that image light is light having image information.
- the control unit 11 can adjust the luminance of the second light ray 391 and the luminance of the first light ray 281 by controlling the light source driving unit 13. That is, the ratio between the luminance of the second light beam 391 and the luminance of the first light beam 281 can be adjusted.
- the second light beam 391 is red light emitted from the laser light source 309.
- the first light beam 281 is blue-green light emitted from the first light source 208.
- the control unit 11 adjusts the light emission amount of each light source based on the video signal. That is, the control unit 11 adjusts the luminance ratio of each light source based on the video signal. Thereby, the power consumption of the liquid crystal display device 102 can be reduced.
- the second light source 309 is arranged to face the end surface 61a of the light guide member 6.
- the end surface 61a is an end surface of the light guide member 6 on the + x axis direction side.
- the end face 61a is a light incident end face.
- the light guide member 6 is disposed in parallel to the display surface 1 a of the liquid crystal panel 1.
- the second light source 309 has a plurality of laser light emitting elements arranged at equal intervals in the y-axis direction.
- the second light source 309 emits a red second light ray 391.
- the spectrum of the red second light ray 391 has a peak in the vicinity of 640 nm.
- the wavelength width of the second light ray 391 is 1 nm in full width at half maximum, and the second light ray 391 has a very narrow spectrum.
- the divergence angle of the second light ray 391 is 40 degrees in full width at half maximum in the fast axis direction (direction in which the divergence angle is large).
- the fast axis direction indicates a direction with a large divergence angle.
- the divergence angle of the second light ray 391 is 10 degrees in full width at half maximum in the slow axis direction (the direction in which the divergence angle is small).
- the slow axis direction indicates a direction with a small divergence angle.
- the full width at half maximum is a wavelength width at which the light intensity is 50% of the maximum intensity with respect to the wavelength at which the light intensity is maximum.
- the full width at half maximum is an angle (full angle) in a direction in which the light intensity is 50% of the maximum intensity with respect to the direction in which the light intensity is maximum.
- the laser light emitting element of the second light source 309 is arranged so that the slow axis direction (direction with a small divergence angle) is parallel to the short side direction of the end surface 61 a of the light guide member 6.
- the short side direction of the end surface 61a of the light guide member 6 is the direction in which the distance between the opposing surfaces of the light guide member 6 is the smallest (in FIG. 10, the z-axis direction).
- the arrangement direction of the laser light emitting element is not limited to this. However, by arranging the laser light emitting element so that the slow axis direction (the direction in which the divergence angle is small) is parallel to the short side direction of the end surface 61a, reflection on the end surface 61c and the end surface 61d of the light guide member 6 is efficiently performed. Done.
- the critical angle is the minimum incident angle at which total reflection occurs. In other words, the critical angle is the smallest incident angle at which light enters from where the refractive index is large to where it is small and total reflection occurs.
- the second light ray 391 is totally reflected at the interface between the light guide member 6 and the air layer. And the 2nd light ray 391 advances the inside of the light guide member 6, repeating reflection. The distance traveled by the second light ray 391 is a predetermined optical distance. Then, the second light ray 391 reaches the end surface 61c while repeating reflection.
- the light diameter of the laser beam 391 emitted from the second light source 309 of the laser light emitting element is extremely small with respect to the size of the end surface 61a of the light guide member 6 in the y-axis direction. That is, the laser light source 309 is a point light source.
- the second light ray 391 spreads due to its divergence angle. For this reason, the second light beam 391 overlaps the light beam of another adjacent laser light emitting element while traveling a predetermined optical distance. The light beams overlap to form linear light with a uniform luminance distribution in the y-axis direction.
- the second light beam 391 Since the light beams of the adjacent laser light emitting elements overlap, the second light beam 391 needs to travel a predetermined optical distance.
- the predetermined optical distance is determined by the divergence angle of the laser light emitting element and the arrangement interval of the laser light emitting elements.
- the second light ray 391 spreads in the arrangement direction of the laser light emitting elements according to its divergence angle inside the light guide member 6.
- the second light ray 391 needs a distance to sufficiently spread in order to generate linear light. This distance is a predetermined optical distance.
- the arrangement direction of the laser light emitting elements is the y-axis direction in FIG.
- the distance from the end surface 61a to the end surface 61c of the light guide member 6 is set longer than a predetermined optical distance.
- the plurality of second light rays 391 emitted from the second light source 309 become linear light having a uniform luminance distribution.
- the light guide member 6 has a first light guide part 62a and a second light guide part 62b.
- the light guide member 6 has a shape in which a rectangular parallelepiped plate-like portion and a trapezoidal pillar-like plate-like portion are combined.
- the 1st light guide part 62a is a rectangular parallelepiped plate-shaped part arrange
- the 2nd light guide part 62b is a plate-shaped part of the trapezoid pillar arrange
- the first light guide 62 a is disposed adjacent to the light reflecting sheet 5 on the ⁇ z-axis direction side.
- the second light guide portion 62b is disposed adjacent to the ⁇ x-axis direction side of the surface light-emitting light guide plate 4.
- the light guide parts 62a and 62b are made of a transparent material such as acrylic resin (for example, PMMA) having a thickness of 2 mm, for example.
- the end faces 61b and 61e are formed in parallel to the yz plane.
- the two end faces 61c and 61d are inclined at an angle of about 45 degrees with respect to the xy plane.
- the end surface 61c of the light guide member 6 is inclined so that the second light ray 391 is reflected from the ⁇ x axis direction to the + z axis direction.
- the end surface 61d of the light guide member 6 is inclined so that the second light ray 391 is reflected from the + z-axis direction to the + x-axis direction.
- the second light ray 391 is incident from the end face 61a. Then, the second light ray 391 repeats total reflection and reaches the end surface 61c. The second light ray 391 is reflected by the end face 61c and travels in the + z-axis direction. Thereafter, the second light ray 391 is reflected by the end face 61d and changes its traveling direction from the + z-axis direction to the + x-axis direction. Thereafter, the second light ray 391 exits from the end surface 61 e toward the surface light-emitting light guide plate 4. On the other hand, the first light beam 281 emitted from the first light source 208 enters the light guide member 6 from the end surface 61b.
- the first light beam 281 passes through the light guide portion 62 b of the light guide member 6 and exits from the end surface 61 e toward the surface light-emitting light guide plate 4.
- the 1st light source 208 is arrange
- the first light source 208 is an LED element that emits a light beam having a relatively large divergence angle. For this reason, even if the first light sources 208 are arranged at equal intervals in the y-axis direction, the first light beam 281 overlaps and becomes linear light between the end surface 61b and the end surface 61e. A plurality of light beams are emitted from adjacent light sources. When these plurality of light beams are spatially overlapped, the luminance distributions of these light beams are averaged to obtain a uniform luminance distribution in the arrangement direction of the light sources. Further, the first light source 208 is disposed to face the end surface 61 b of the light guide member 6. The first light beam 281 is emitted from the first light source 208. Thereafter, the first light beam 281 travels toward the end surface 61b.
- the blue-green first light beam 281 is emitted from the first light source 208.
- the first light beam 281 is mixed with the red second light beam 391 emitted from the second light source 309 to become a white light beam 343.
- the first light ray 281 has peaks at around 450 nm and around 530 nm.
- the first light beam 281 is blue-green light having a continuous spectrum in a band from 420 nm to 580 nm.
- the first light source 208 can be a light source that emits blue light and green light.
- the light source has a combination of an excitation light source and a phosphor.
- the first light source 208 can be a light source having a phosphor that emits blue light and green light by ultraviolet light.
- the light source emits blue light and green light by the ultraviolet light exciting the phosphor.
- the first light source 208 may be a light source that emits blue light and green light by exciting blue phosphors with blue light.
- a method of arranging the two rows of the first light source 208 and the second light source 309 for example, a method of arranging the two rows of the first light source 208 and the second light source 309 along the incident end surface 41a of the surface light emitting light guide plate 4 is considered. It is done. However, the arrangement of two rows of light sources adjacent to each other is to collect the light sources in one place. Two rows of light sources are arranged adjacent to each other, and the light sources are gathered in one place, whereby the temperature around the light sources rises due to the heat generated by the LED elements and the laser light emitting elements. The luminous efficiency of the LED element and the laser light emitting element decreases due to the temperature rise around this.
- the lifetime of the LED element and the laser light-emitting element is shortened due to the temperature rise around the periphery. Therefore, when arranging two rows of light sources, it is desirable that the respective light sources are arranged apart from each other. Thereby, it can suppress that ambient temperature rises by light emission of a light source. Thereby, the fall of the luminous efficiency of the light source by ambient temperature rise can be suppressed. In addition, the lifetimes of the first light source 208 and the second light source 309 can be extended.
- the temperature characteristics of the LED element are different from the temperature characteristics of the laser light emitting element. Compared with the LED element, the amount of light emitted from the laser light emitting element is likely to change with temperature, and the wavelength of the laser light emitting element is likely to change with temperature. For this reason, it is necessary to keep the temperature of the laser light emitting element at an appropriate temperature. In order to keep the temperature of the laser light emitting element at an appropriate temperature, it is desirable not to arrange a heat source around the laser light source. A light source using an LED element radiates heat when turned on. The laser light source emits heat when turned on. That is, the light source using the LED element is arranged away from the laser light source. This is important.
- the end surface 61e of the light guide member 6 is opposed to the end surface 41a on the -x axis direction side of the surface light-emitting light guide plate 4.
- a blue-green first light beam 281 is emitted from the first light source 208.
- the red second light ray 391 is emitted from the second light source 309.
- the blue-green first light beam 281 and the red second light beam 391 are mixed inside the light guide portion 62 b of the light guide member 6.
- the first light beam 281 and the second light beam 391 become white linear light.
- the first light beam 281 and the second light beam 391 are emitted from the end surface 61 e toward the surface light-emitting light guide plate 4.
- the light beam 343 is white linear light.
- the control unit can control the light source driving unit to adjust the ratio of the luminance of the first light beam 281 and the luminance of the second light beam 391 to produce white linear light.
- the light guide member 6 has been described as a transparent member having a thickness of 2 mm, but is not limited to a transparent member having a thickness of 2 mm.
- the first function is a function in which the light guide member 6 guides the first light beam 281 and the second light beam 391 to the surface emitting light guide plate 4.
- the first light beam 281 is a light beam emitted from the first light source 208.
- the second light ray 391 is a light ray emitted from the second light source 309.
- the second function is a function that the light guide member 6 mixes the first light beam 281 and the second light beam 391. If it is the structure which has these two functions, the light guide member 6 may have another structure. For example, the same effect can be obtained by providing a reflective film on the end faces 61c and 61d.
- the light guide member 6 can take the same form as that of FIG. 4 of the first embodiment.
- the light guide member 108 shown in FIG. 4 is composed of three parts, reflecting members 181, 182, and 183.
- the reflecting surfaces 181a, 182a, 183a of the reflecting members 181, 182 and 183 are mirror surfaces.
- the reflecting member 181 and the reflecting member 182 are shown as separate parts, both ends in the y-axis direction can be connected to form a hollow one part.
- the light guide member 183 can be configured such that a part of the structural member is a mirror surface.
- the liquid crystal display device 102 is considered to be thin.
- the liquid crystal display device 102 is also considered to be lightweight. Therefore, it is desirable to use the surface emitting light guide plate 4 having a small thickness. However, if the thickness is reduced, the rigidity of the light guide member 6 is reduced. For this reason, it is necessary to consider problems such as a decrease in rigidity of the light guide member 6.
- the surface emitting light guide plate 4 is arranged in parallel to the display surface 1 a of the liquid crystal panel 1.
- the surface light-emitting light guide plate 4 has a micro optical element 42 on the back surface.
- the back surface is a surface opposite to the liquid crystal panel 1 and is a surface on the side in the ⁇ z-axis direction.
- the light beam 343 is light that travels inside the surface emitting light guide plate 4.
- the illumination light 344 is light emitted in the + z axis direction.
- the micro optical element 42 changes the light beam 343 into illumination light 344.
- the illumination light 344 exits from the surface light-emitting light guide plate 4 toward the back surface 1 b of the liquid crystal panel 1.
- the surface emitting light guide plate 4 is a component made of a transparent material such as acrylic resin (for example, PMMA).
- the surface-emitting light guide plate 4 is a plate-like member having a thickness of 4 mm. Similar to FIG. 5 of the first embodiment, the surface light-emitting light-guiding plate 4 has the micro optical element 42 on the back surface 41b.
- the micro optical element 42 has a hemispherical convex shape protruding in the ⁇ z-axis direction.
- the light beam 343 enters from the end face 41 a of the surface light-emitting light guide plate 4.
- the light beam 343 is totally reflected at the interface between the surface emitting light guide plate 4 and the air layer.
- the light beam 343 propagates inside the light guide pair 4.
- the light beam 343 travels in the + x-axis direction while repeating reflection.
- the traveling direction of the light beam 343 changes, some of the light beams 343 do not satisfy the total reflection condition at the interface between the surface of the surface emitting light guide plate 4 and the air layer.
- the light beam When the light beam does not satisfy the total reflection condition, the light beam is emitted from the surface of the surface light-emitting light guide plate 4 toward the back surface 1 b of the liquid crystal panel 1.
- the surface of the surface light-emitting light guide plate 4 is a surface on the liquid crystal panel 1 side.
- the arrangement density of the micro optical elements 42 changes at a position in the xy plane on the surface light-emitting light guide plate 4.
- the arrangement density is the number of the micro optical elements 42 per unit area, the size of the micro optical elements 42, or the like.
- the in-plane luminance distribution of the illumination light 344 can be controlled by changing the arrangement density of the micro optical elements 42.
- the illumination light 344 is light emitted from the surface emitting light guide plate 4.
- the in-plane luminance distribution is a distribution indicating the level of luminance with respect to a position expressed in two dimensions on an arbitrary plane.
- the in-plane here refers to the display surface.
- the arrangement density of the micro optical elements 42 changes with respect to the position of the light beam 343 in the traveling direction.
- the traveling direction of the light beam 343 is the + x-axis direction in FIG.
- the surface light-emitting light guide plate 4 has a micro optical element 42 in a region from the vicinity of the end surface 41a to the end surface 41c.
- the end surface 41c is an end surface facing the end surface 41a.
- the arrangement density continuously changes from sparse to dense from the vicinity of the end face 41a toward the end face 41c.
- the micro optical element 42 has a convex lens shape.
- the shape of the micro optical element 42 is not limited to the convex lens shape.
- the function necessary for the micro optical element 42 is that the micro optical element 42 reflects the light beam 343 in the + z-axis direction and emits the light beam 343 toward the back surface 1 b of the liquid crystal panel 1.
- the light beam 343 is light that travels in the x-axis direction inside the surface emitting light guide plate 4. If it has this function, the micro optical element 42 may have a different shape. For example, a prism shape or a random uneven pattern has the same function.
- the illumination light 344 is light emitted from the surface-emitting light guide plate 4 toward the liquid crystal panel 1.
- the illumination light 344 may be reflected by the first optical sheet 2 and the second optical sheet 3 and travel in the ⁇ z-axis direction.
- the liquid crystal display device 102 according to the second embodiment includes a light reflection sheet 5 on the ⁇ z-axis direction side of the surface light-emitting light guide plate 4.
- the light reflecting sheet 5 directs the reflected light traveling in the ⁇ z-axis direction again in the + z-axis direction. Thereby, the liquid crystal display device 102 can use light efficiently.
- the liquid crystal display device 102 of Embodiment 3 has the light source 281 and the second light source 309 at two locations.
- the first light source 208 using an LED element is disposed on the side surface of the surface light-emitting light guide plate 4.
- the laser light source 309 is disposed on the back surface of the surface emitting light guide plate 4.
- the liquid crystal display device 102 can suppress the increase in thickness (dimension in the z-axis direction) and increase the number of light sources.
- the size of the backlight unit 202 is suppressed with respect to the display area of the liquid crystal display device 102, so that the liquid crystal display device 102 can be realized with high brightness and thinness.
- the display area is an area for displaying an effective image.
- the display area is in the x-axis direction and the y-axis direction in terms of coordinates.
- the light sources are arranged on the side surface and the back surface of the surface light-emitting light guide plate 4, it is possible to mitigate the increase in ambient temperature due to the heat generated by each light source. Thereby, the fall of the luminous efficiency of the light source by ambient temperature rise can be suppressed. In addition, the lifetimes of the first light source 208 and the second light source 309 can be extended.
- the light source of the backlight of the liquid crystal display device 102 of Embodiment 3 employs a laser light source with a narrow wavelength width.
- the color purity of the display color can be increased.
- Fluorescent lamps and LED elements are widely used.
- the laser light source can express more vivid colors than the fluorescent lamp and the LED element.
- the laser light source 309 of the liquid crystal display device 102 emits red light.
- the first light source 208 of the liquid crystal display device 102 emits blue-green light.
- Blue-green is a color obtained by mixing blue and green.
- conventionally used fluorescent lamps have the emission spectrum peak in the red region in the orange wavelength region.
- a white LED element using a yellow phosphor also has an emission spectrum peak in the red region in the orange wavelength region. That is, the wavelength peak in the red region is in an orange region that is shifted from the red region.
- the color purity is to be increased in red, the amount of transmitted light is extremely reduced and the luminance is significantly reduced.
- By replacing the fluorescent lamp with a red laser light emitting element it is possible to suppress a decrease in the amount of light transmitted through the color filter. Further, the effect of improving the color purity can be obtained.
- a red laser light emitting element having a peak wavelength of 640 nm is used for the second light source 309.
- the present invention is not limited to this.
- a red laser light emitting element having a wavelength peak different from 640 nm can be used.
- a laser light emitting element that emits blue or green light can be used.
- the light from the first light source 208 needs to be mixed with the light from the second light source 309 to become white light. That is, the light from the first light source 208 is complementary to the light from the second light source 309.
- a white fluorescent lamp or a white LED element is used as a light source.
- the transmission wavelength of the color filter of the liquid crystal panel 1 is set to be narrow. In this case, the luminance of the image decreases as the light loss due to the color filter increases.
- the liquid crystal display device 102 of Embodiment 3 uses a single color laser light emitting element. Single color light has high color purity. By using a single color laser light emitting element, the color purity of red is improved. The liquid crystal display device 102 can widen the color reproduction range of display colors. Further, since the red color purity is improved, the liquid crystal display device 102 can reduce light loss due to the color filter. For this reason, the liquid crystal display device 102 can suppress a decrease in brightness. Despite the low power consumption, the liquid crystal display device 102 can realize a wide color gamut with high brightness.
- the liquid crystal display device 102 of Embodiment 2 has one light guide member 6.
- the light guide member 6 does not need to be configured by one member.
- the light guide member 6 may be configured as shown in FIGS. 6 and 7 described in the first embodiment.
- the liquid crystal display device 102 has a configuration in which light emitted from two light sources arranged at different positions is incident from the short end face of the surface light-emitting light guide plate 4.
- the long end face of the surface light-emitting light guide plate 4 can be used as the incident surface.
- the long end face is an end face parallel to the xz plane in FIG.
- the light source driving unit can reduce power consumption and improve contrast by reducing stray light by individually controlling outputs of the first light source 208 and the second light source 309 based on image signals. be able to. This is because the light unnecessary for display can be extinguished by controlling the first light source 208 and the second light source 209 separately. Further, the output of light unnecessary for display can be reduced. Thus, stray light can be reduced by reducing unnecessary light. Stray light is light that travels outside the normal optical path in an optical device, and is harmful to image formation.
- FIG. 12 is a cross-sectional view schematically showing an example of the configuration of the liquid crystal display device 103 (including the surface light source device 203) according to the fourth embodiment.
- the surface light source device 203 includes a surface emitting light guide plate 4, a light reflection sheet 5, a light guide member 406, a first light source 208, and a second light source 209. Further, the surface light source device 203 includes a component having the function of the light guide member 406.
- the same or corresponding components as those shown in FIG. 10 (Embodiment 3) are denoted by the same reference numerals.
- the liquid crystal display device 103 is a transmissive display device.
- the liquid crystal display device 103 of the fourth embodiment the light emitted from the two light sources is incident on the surface light-emitting light guide plate 4 separately.
- the two light sources are arranged at two different places.
- the light sources arranged at two locations are a first light source 208 using LED elements and a second light source 309 using laser light emitting elements.
- the liquid crystal display device 103 newly has a light guide member 406 instead of the light guide member 6 of the third embodiment.
- the liquid crystal display device 103 is the same as that of Embodiment 3 except for the above differences.
- the fourth embodiment is different from the first and second embodiments in the components of the first light source 208, the second light source 309, and the light guide member 406, and the other components are the same. Also in the fourth embodiment, the modes of FIGS. 4, 6 and 7 other than the mode of FIG. 1 of the first embodiment can be taken.
- the liquid crystal display device 103 of Embodiment 4 has an LED element that emits a blue-green first light beam 281 as the first light source 208.
- the liquid crystal display device 103 uses a laser light emitting element that emits a red second light beam 391 as the second light source 309.
- the blue-green first light beam 281 is a mixture of blue light and green light.
- the first light beam 281 emitted from the first light source 208 is directly incident on the surface emitting light guide plate 4. For this reason, the loss of light generated at the interface between the light guide member 6 and the air layer, which has occurred in the first to third embodiments, is suppressed.
- the liquid crystal display device 103 can obtain higher light utilization efficiency.
- Embodiment 4 has the same configuration as FIG. 11 of Embodiment 3. Therefore, the fourth embodiment will be described with reference to FIG.
- the liquid crystal display device 103 includes a liquid crystal panel driving unit 12 and a light source driving unit 13.
- the liquid crystal panel driving unit 12 drives the liquid crystal panel 1.
- the light source driving unit 13 drives the first light source and the second light source. Note that the first light source is the first light source 208.
- the second light source is a laser light source 309.
- the control unit 11 controls the operation of the liquid crystal panel driving unit 12 and the operation of the light source driving unit 13.
- the control unit 11 performs image processing on the input video signal to generate a liquid crystal panel control signal and a light source control signal.
- the control unit 11 supplies a liquid crystal panel control signal to the liquid crystal panel drive unit 12 and supplies a light source control signal to the light source drive unit 13.
- the liquid crystal panel driving unit 12 drives the liquid crystal display device based on the liquid crystal panel control signal.
- the light source driving unit 13 drives the first light source 208 and the second light source 309 based on the light source control signal.
- the red second light beam 391 is emitted from the laser light source 309.
- the second light ray 391 enters the light guide member 406 from the end surface 461a.
- the second light ray 391 travels in the ⁇ x axis direction inside the light guide member 406. Thereafter, the second light ray 391 is reflected twice to change the traveling direction in the + x-axis direction.
- the second light ray 391 enters the inside of the surface light-emitting light guide plate 4 from the end face 41a.
- the blue-green first light beam 281 is emitted from the first light source 208.
- the first light beam 281 enters the inside of the surface light-emitting light guide plate 4 from the end face 41a in the same manner as the second light beam 391.
- Blue-green is a color having luminance peaks in blue and green. After entering from the end face 41 a of the surface light-emitting light guide plate 4, the first light ray 281 travels in the + x-axis direction while being mixed with the second light ray 391.
- the surface-emitting light guide plate 4 has a micro optical element 42 on the surface in the ⁇ z-axis direction side.
- the micro optical element 42 converts a light beam, which is a mixture of the first light beam 281 and the second light beam 391, into illumination light 344.
- the illumination light 344 travels in the + z axis direction.
- the illumination light 344 is emitted toward the back surface 1b of the liquid crystal panel 1.
- the illumination light 344 passes through the second optical sheet 3 and the first optical sheet 2 and irradiates the back surface 1 b of the liquid crystal panel 1.
- the first optical sheet 2 has a function of directing light emitted from the surface light-emitting light guide plate 4 toward the back surface 1 b of the liquid crystal panel 1.
- the second optical sheet 3 has a function of suppressing optical influences such as fine illumination unevenness.
- the light reflecting sheet 5 is disposed on the ⁇ z-axis direction side of the surface emitting light guide plate 4. Further, the light reflecting sheet 5 is disposed on the + z axis direction side of the light guide member 406. Light emitted from the surface light-emitting light guide plate 4 in the ⁇ z-axis direction is reflected by the light reflecting sheet 5. The light reflected by the light reflecting sheet 5 is used as illumination light 344 that irradiates the back surface 1 b of the liquid crystal panel 1.
- a light reflecting sheet based on a resin such as polyethylene terephthalate can be used.
- the light reflection sheet 5 can use the light reflection sheet which vapor-deposited the metal on the surface of the board
- the liquid crystal layer of the liquid crystal panel 1 is arranged in parallel to the xy plane.
- the display surface 1a of the liquid crystal panel 1 has a rectangular shape. Two adjacent sides of the display surface 1a are orthogonal to each other. The short side is parallel to the y-axis. The long side is parallel to the x-axis.
- the rectangular shape is a rectangular shape including a square.
- the liquid crystal panel driving unit 12 changes the light transmittance of the liquid crystal layer in units of pixels based on the liquid crystal panel control signal received from the control unit 11.
- the liquid crystal panel driving unit 12 changes the light transmittance of the liquid crystal layer in units of pixels based on the liquid crystal panel control signal received from the control unit 11.
- Each pixel is further composed of three sub-pixels.
- the first subpixel includes a color filter that transmits only red light.
- the second subpixel includes a color filter that transmits only green light.
- the third subpixel includes a color filter that transmits only blue light.
- the control unit 11 controls the transmittance of each sub-pixel, so that the liquid crystal panel 1 creates a color image. That is, the liquid crystal panel 1 creates image light by spatially modulating the illumination light 344 incident from the surface light-emitting light guide plate 4. This image light is emitted from the display surface 1a. Note that image light is light having image information.
- the control unit 11 can adjust the luminance of the second light beam 391 and the luminance of the first light beam 281 by controlling the light source driving unit 13.
- the control unit 11 adjusts the light emission amount of each light source based on the video signal. Thereby, the power consumption of the liquid crystal display device 103 can be reduced.
- the second light beam 391 is red light emitted from the laser light source 309.
- the first light beam 281 is blue-green light emitted from the first light source 208.
- the second light source 309 using the laser light emitting element faces the end surface 461a of the light guide member 406.
- the end surface 461 a is an end surface on the + x axis direction side of the light guide member 406.
- the second light ray 391 enters the light guide member 406 from the end surface 461a.
- the light guide member 406 is disposed in parallel to the display surface 1 a of the liquid crystal panel 1.
- the second light source 309 is composed of a plurality of laser light emitting elements.
- the plurality of laser light emitting elements are arranged in the y-axis direction at equal intervals.
- the second light source 309 emits a red second light ray 391.
- the spectrum of the red second light ray 391 has a peak in the vicinity of 640 nm.
- the wavelength width of the second light ray 391 is 1 nm in full width at half maximum, and the second light ray 391 has a very narrow spectrum.
- the divergence angle of the second light ray 391 is 40 degrees in full width at half maximum in the fast axis direction (direction in which the divergence angle is large).
- the divergence angle of the second light ray 391 is 10 degrees in full width at half maximum in the slow axis direction (the direction in which the divergence angle is small).
- the laser light emitting element of the second light source 309 is arranged so that the slow axis direction (the direction with a small divergence angle) is parallel to the short side direction of the end surface 461a of the light guide member 406.
- the short side direction of the end surface 461a of the light guide member 406 is the direction in which the distance between the opposing surfaces of the light guide member 406 is the narrowest (in the z-axis direction in FIG. 12).
- the arrangement direction of the laser light emitting element is not limited to this.
- the laser light emitting element by arranging the laser light emitting element so that the slow axis direction (the direction with a small divergence angle) is parallel to the short side direction of the end surface 461a, reflection on the end surface 461c and the end surface 461b of the light guide member 406 is efficiently performed. Done. This is because, when the divergence angle in the short side direction of the end surface 461a is large, a part of the second light ray 391 has an incident angle on the end surfaces 461c and 461b smaller than the critical angle and is not reflected by the end surfaces 461c and 461b. is there. However, if a mirror surface is formed on the end surfaces 461c and 461b, this problem is eliminated.
- the second light ray 391 is totally reflected at the interface between the light guide member 406 and the air layer. Then, the second light ray 391 travels inside the light guide member 406. The distance traveled by the second light ray 391 is a predetermined optical distance. The second light ray 391 reaches the end surface 461c while repeating reflection.
- the light diameter of the laser beam 391 as the second light beam emitted from the second light source 309 using the laser light emitting element is extremely small with respect to the size of the end surface 461a of the light guide member 406 in the y-axis direction. That is, the second light source 309 using the laser light emitting element is a point light source.
- the second light ray 391 spreads due to its divergence angle. For this reason, the second light beam 391 overlaps the light beam of another adjacent laser light emitting element while traveling a predetermined optical distance. The light rays overlap and become linear light with a uniform luminance distribution in the y-axis direction.
- the second light beam 391 Since the light beams of the adjacent laser light emitting elements overlap, the second light beam 391 needs to travel a predetermined optical distance.
- the predetermined optical distance is determined by the divergence angle of the laser light emitting element and the arrangement interval of the laser light emitting elements.
- the second light ray 391 spreads in the arrangement direction of the laser light emitting elements by the divergence angle of the light guide member 406 by its divergence angle.
- the second light ray 391 needs a distance to sufficiently spread in order to generate linear light. This distance is a predetermined optical distance.
- the arrangement direction of the laser light emitting elements is the y-axis direction in FIG.
- the distance from the end surface 461a to the end surface 461c of the light guide member 406 is set longer than a predetermined optical distance.
- the plurality of second light rays 391 emitted from the second light source 309 become linear light having a uniform luminance distribution.
- the light guide member 406 is a rectangular parallelepiped plate-shaped light guide part 462a and a triangular light guide part 462b.
- the two light guide portions 462a and 462b are made of a transparent material such as an acrylic resin (for example, PMMA) having a thickness of 2 mm, for example.
- the end face 461d is formed in parallel to the yz plane.
- the end surface 461d faces the end surface 41a on the side of the surface-emitting light-guiding plate 4 in the ⁇ x-axis direction.
- the two end faces 461b and 461c are inclined at an angle of approximately 45 degrees with respect to the xy plane.
- the end surface 461c of the light guide member 406 is inclined so that the second light ray 391 is reflected from the ⁇ x axis direction to the + z axis direction.
- the end surface 461b of the light guide member 406 is inclined so that the second light ray 391 is reflected from the + z-axis direction to the + x-axis direction.
- the second light ray 391 is incident from the end face 461a.
- the second light ray 391 repeats total reflection and reaches the end surface 461c.
- the second light ray 391 is reflected by the end face 461c and travels in the + z-axis direction. Thereafter, the second light ray 391 is reflected by the end face 461b and changes the traveling direction from the + z-axis direction to the + x-axis direction. Thereafter, the second light ray 391 is emitted from the end surface 461d toward the surface light-emitting light guide plate 4.
- the first light source 208 is an LED element that emits a light beam having a relatively large divergence angle. For this reason, even if the 1st light source 208 arranges an LED element at equal intervals in the y-axis direction, the 1st light ray 281 overlaps and becomes linear light. That is, the luminance distribution of the first light rays 281 is averaged, and the first light rays 281 have a uniform luminance distribution in the arrangement direction of the first light sources 208.
- a plurality of light beams are emitted from adjacent light sources. When these plurality of light beams are spatially overlapped, the luminance distributions of these light beams are averaged to obtain a uniform luminance distribution in the arrangement direction of the light sources.
- the first light source 208 is disposed to face the end surface 41 a of the surface light-emitting light guide plate 4.
- the first light beam 281 is emitted from the first light source 208. Thereafter, the first light beam 281 travels toward the end surface 41a.
- the blue-green first light beam 281 is emitted from the first light source 208.
- the first light beam 281 is mixed with the red second light beam 391 emitted from the second light source 309 to become a white light beam 343.
- the first light ray 281 has peaks at around 450 nm and around 530 nm.
- the first light beam 281 is blue-green light having a continuous spectrum in a band from 420 nm to 580 nm.
- the first light source 208 can be a light source that emits blue light and green light. Further, the light source has a configuration in which an excitation light source and a phosphor are combined.
- the first light source 208 a light source having a phosphor that emits blue light and green light by ultraviolet light can be used.
- the light source emits blue light and green light by the ultraviolet light exciting the phosphor.
- the first light source 208 may be a light source that emits blue light and green light by exciting blue phosphors with blue light.
- a method of arranging the two rows of the first light source 208 and the second light source 309 for example, a method of arranging the two rows of the first light source 208 and the second light source 309 along the incident end surface 41a of the surface light emitting light guide plate 4 is considered. It is done. However, the arrangement of two rows of light sources adjacent to each other is to collect the light sources in one place. Two rows of light sources are arranged adjacent to each other, and the light sources are gathered in one place, whereby the temperature around the light sources rises due to the heat generated by the LED elements and the laser light emitting elements. Due to the temperature rise around this, the luminous efficiency of the LED element and the laser light emitting element decreases.
- the lifetime of the LED element and the laser light emitting element is shortened due to the temperature rise around the periphery. Therefore, when arranging two rows of light sources, it is desirable that the respective light sources are arranged apart from each other. Thereby, it can suppress that ambient temperature rises by light emission of a light source. That is, a decrease in light emission efficiency of the light source due to an increase in ambient temperature can be suppressed. In addition, the lifetimes of the first light source 208 and the second light source 309 can be extended.
- the temperature characteristics of the LED element are different from the temperature characteristics of the laser light emitting element. Compared with the LED element, the amount of light emitted from the laser light emitting element is likely to change with temperature, and the wavelength of the laser light emitting element is likely to change with temperature. For this reason, it is necessary to keep the temperature of the laser light emitting element at an appropriate temperature. In order to keep the temperature of the laser light emitting element at an appropriate temperature, it is desirable not to arrange a heat source around the laser light source. A light source using an LED element radiates heat when turned on. The laser light source emits heat when turned on. That is, the light source using the LED element is arranged away from the laser light source. This is important.
- the light guide member 406 has been described as a transparent member having a thickness of 2 mm, but is not limited to a transparent member having a thickness of 2 mm.
- the function required for the light guide member 406 is a function that the light guide member 406 guides the second light beam 391 to the surface light-emitting light guide plate 4.
- the second light ray 391 is a light ray emitted from the second light source 309.
- the light guide member 406 may have another configuration. For example, the same effect can be obtained by providing a reflective film on the end surfaces 461b and 461c.
- FIG. 13 is a cross-sectional view schematically showing an example of a surface-emitting light guide plate and its peripheral structure in the surface light source device 203 of the fourth embodiment.
- the reflecting surfaces 481a, 481b, 481c, and 482a of the reflecting members 481 and 482 are mirror surfaces.
- the reflecting member 481 and the reflecting member 482 are shown as separate parts, both ends in the y-axis direction can be connected to form a hollow one part.
- the liquid crystal display device 103 is considered to be thin.
- the liquid crystal display device 103 is also considered to be light. Therefore, it is desirable to use the surface emitting light guide plate 4 having a small thickness. However, if the thickness is reduced, the rigidity of the light guide member 406 is reduced. For this reason, it is necessary to consider problems such as a decrease in rigidity of the light guide member 406.
- the first light beam 281 is emitted from the first light source 208.
- the second light beam 391 is emitted from the second light source 309 using a laser light emitting element.
- the blue-green first light beam 281 is mixed with the red second light beam 391 inside the surface emitting light guide plate 4.
- the 1st light ray 281 and the 2nd light ray 391 become white linear light.
- the control unit 11 can control the light source driving unit 13 to adjust the luminance ratio of the first light beam 281 and the second light beam 391.
- the control part 11 can produce white linear light.
- the surface emitting light guide plate 4 is arranged in parallel to the display surface 1 a of the liquid crystal panel 1.
- the surface light-emitting light guide plate 4 has a micro optical element 42 on the back surface.
- the back surface is a surface opposite to the liquid crystal panel 1 and is a surface on the side in the ⁇ z-axis direction.
- the first light beam 281 and the second light beam 391 travel inside the surface emitting light guide plate 4.
- the micro optical element 42 converts the first light beam 281 and the second light beam 391 into illumination light 344.
- the illumination light 344 is light emitted in the + z axis direction. Thereafter, the illumination light 344 is irradiated toward the back surface 1 b of the liquid crystal panel 1.
- the surface emitting light guide plate 4 is a component made of a transparent material such as acrylic resin (for example, PMMA).
- the surface-emitting light guide plate 4 is a plate-like member having a thickness of 4 mm. Similar to FIG. 5 of the first embodiment, the surface light-emitting light-guiding plate 4 has the micro optical element 42 on the back surface 41b.
- the micro optical element 42 has a hemispherical convex shape protruding in the ⁇ z-axis direction.
- the first light beam 281 and the second light beam 391 are incident from the end surface 41 a of the surface light-emitting light guide plate 4.
- the first light beam 281 and the second light beam 391 are totally reflected at the interface between the surface emitting light guide plate 4 and the air layer.
- the first light beam 281 and the second light beam 391 propagate while repeating reflection inside the light guide pair 4.
- the light beam 343 travels in the + x-axis direction while repeating reflection.
- the first light beam 281 and the second light beam 391 are incident on the micro optical element 42, they are reflected by the curved surface of the micro optical element 42 to change the traveling direction.
- the first light beam 281 and the second light beam 391 satisfy the total reflection condition at the interface between the surface of the surface light-emitting light guide plate 4 and the air layer. There are rays that disappear.
- the light beam does not satisfy the total reflection condition, the light beam is emitted from the surface of the surface light-emitting light guide plate 4 toward the back surface 1 b of the liquid crystal panel 1.
- the surface of the surface light-emitting light guide plate 4 is a surface on the liquid crystal panel 1 side.
- the arrangement density of the micro optical elements 42 changes at a position in the xy plane on the surface light-emitting light guide plate 4.
- the arrangement density is the number of the micro optical elements 42 per unit area, the size of the micro optical elements 42, or the like.
- the in-plane luminance distribution of the illumination light 344 can be controlled by changing the arrangement density of the micro optical elements 42.
- the illumination light 344 is light emitted from the surface emitting light guide plate 4.
- the in-plane luminance distribution is a distribution indicating the level of luminance with respect to a position expressed in two dimensions on an arbitrary plane.
- the in-plane here refers to the display surface.
- the arrangement density of the micro optical elements 42 changes with respect to the position of the first light beam 281 and the second light beam 391 in the traveling direction.
- the traveling direction of the first light beam 281 and the second light beam 391 is the + x-axis direction in FIG.
- the surface light-emitting light guide plate 4 has a micro optical element 42 in a region from the vicinity of the end surface 41a to the end surface 41c.
- the end surface 41c is an end surface facing the end surface 41a.
- the arrangement density continuously changes from sparse to dense from the vicinity of the end face 41a toward the end face 41c.
- the micro optical element 42 has a convex lens shape.
- the curvature of the surface is about 0.15 mm.
- the maximum height is about 0.005 mm.
- the refractive index is about 1.49.
- the material of the surface emitting light guide plate 4 and the micro optical element 42 can be acrylic resin.
- the material of the surface emitting light guide plate 4 and the micro optical element 42 is not limited to acrylic resin. A material having good light transmittance and excellent moldability can be employed.
- the acrylic resin another resin material such as a polycarbonate resin can be adopted, or a glass material can be adopted.
- the micro optical element 42 has a convex lens shape.
- the shape of the micro optical element 42 is not limited to the convex lens shape.
- the function necessary for the micro optical element 42 is that the micro optical element 42 reflects the first light beam 281 and the second light beam 391 in the + z-axis direction, and the first light beam 281 and the second light beam 391 are directed toward the back surface 1b of the liquid crystal panel 1. Is emitted.
- the first light beam 281 and the second light beam 391 are light that travels in the x-axis direction inside the surface emitting light guide plate 4.
- the micro optical element 42 may have a different shape. For example, a prism shape or a random uneven pattern has the same function.
- the surface emitting light guide plate 4 is not limited to a thickness of 4 mm. In consideration of reduction in thickness and weight of the liquid crystal display device 103, it is desirable to use the surface emitting light guide plate 4 having a small thickness.
- the illumination light 344 is light emitted from the surface emitting light guide plate 4 toward the liquid crystal panel 1.
- the illumination light 344 may be reflected by the first optical sheet 2 and the second optical sheet 3 and travel in the ⁇ z-axis direction.
- the liquid crystal display device 103 according to the fourth embodiment includes the light reflecting sheet 5 on the side in the ⁇ z-axis direction of the surface emitting light guide plate 4.
- the light reflecting sheet 5 directs the reflected light traveling in the ⁇ z-axis direction again in the + z-axis direction. Thereby, the liquid crystal display device 103 can use light efficiently.
- the liquid crystal display device 103 includes the light source 281 and the second light source 309 at two locations.
- the first light source 208 using an LED element is disposed on the side surface of the surface light-emitting light guide plate 4.
- the laser light source 309 as the second light source is disposed on the back surface of the surface emitting light guide plate 4.
- the liquid crystal display device 103 can suppress the increase in thickness (dimension in the z-axis direction) and increase the number of light sources.
- a high-luminance and thin liquid crystal display device 103 can be realized without increasing the size of the backlight unit 203 in the display area of the liquid crystal display device 103.
- the size of the backlight unit 203 is suppressed with respect to the display area of the liquid crystal display device 103, and the liquid crystal display device 103 can realize high brightness and thinness.
- the display area is an area for displaying an effective image.
- the display area is in the x-axis direction and the y-axis direction in terms of coordinates.
- the light sources are arranged on the side surface and the back surface of the surface light-emitting light guide plate 4, it is possible to mitigate the increase in ambient temperature due to the heat generated by each light source. Thereby, the fall of the luminous efficiency of the light source by ambient temperature rise can be suppressed. In addition, the lifetimes of the first light source 208 and the second light source 309 can be extended.
- a light source using a laser light emitting element having a narrow wavelength width is employed as the light source of the backlight of the liquid crystal display device 103 of Embodiment 4.
- a light source using a laser light emitting element By adopting a light source using a laser light emitting element, the color purity of the display color can be increased.
- a light source using a laser light emitting element rather than a widely used fluorescent lamp and LED element can express vivid colors.
- the second light source 309 using the laser light emitting element of the liquid crystal display device 103 emits red light.
- the first light source 208 of the liquid crystal display device 103 emits blue-green light.
- Blue-green is a color obtained by mixing blue and green.
- conventionally used fluorescent lamps have the emission spectrum peak in the red region in the orange wavelength region.
- a white LED element using a yellow phosphor also has an emission spectrum peak in the red region in the orange wavelength region. That is, the wavelength peak in the red region is in an orange region that is shifted from the red region.
- the color purity is to be increased in red, the amount of transmitted light is extremely reduced and the luminance is significantly reduced.
- By replacing the fluorescent lamp with a red laser light emitting element it is possible to suppress a decrease in the amount of light transmitted through the color filter. Further, the effect of improving the color purity can be obtained.
- a red laser light emitting element having a peak wavelength at 640 nm is used for the second light source 309.
- the present invention is not limited to this.
- a red laser light emitting element having a wavelength peak different from 640 nm can be used.
- a laser light emitting element that emits blue or green light can be used.
- the light from the first light source 208 needs to be mixed with the light from the second light source 309 to become white light. That is, the light from the first light source 208 is complementary to the light from the second light source 309.
- the liquid crystal display device 103 uses a single color laser light emitting element. Single color light has high color purity. By using a single color laser light emitting element, the color purity of red is improved. The liquid crystal display device 103 can expand the color reproduction range of display colors. Further, by improving the color purity of red, the liquid crystal display device 103 can reduce light loss due to the color filter. For this reason, the liquid crystal display device 103 can suppress a decrease in brightness. Despite the low power consumption, the liquid crystal display device 101 can realize a wide color gamut with high brightness.
- the laser light emitting element is superior in monochromaticity than the LED element.
- the transmission wavelength of the color filter can be set narrower. Therefore, the laser light source can improve color purity compared with the light source using a single color LED element.
- a light source using a laser light emitting element has better electrical / light conversion efficiency than a light source using a single color LED element. Therefore, a light source using a laser light emitting element can be driven with lower power consumption than a light source using a single color LED element. Furthermore, a light source using a laser light emitting element has higher directivity than a light source using an LED element. Therefore, the laser light source can improve the coupling efficiency with the light guide member 406.
- the coupling efficiency is the amount of light incident on the subsequent optical system with respect to the amount of light emitted from the light source.
- the liquid crystal display device 103 has a configuration in which light emitted from two light sources arranged at different positions is incident from the short end face of the surface light-emitting light-guiding plate 4.
- the long end face of the surface light-emitting light guide plate 4 can be used as the incident surface.
- the long end face is an end face parallel to the xz plane in FIGS. 1, 6, and 7.
- the light source driving unit can reduce power consumption and improve contrast by reducing stray light by individually controlling the outputs of the first light source 208 and the second light source 309 based on image signals. be able to. This is because the light unnecessary for display can be extinguished by controlling the first light source 208 and the second light source 209 separately. Further, the output of light unnecessary for display can be reduced. Thus, stray light can be reduced by reducing unnecessary light. Stray light is light that travels outside the normal optical path in an optical device, and is harmful to image formation.
- FIG. 14 is a cross-sectional view schematically showing an example of the configuration of the liquid crystal display device 104 (including the surface light source device 204) according to the fifth embodiment.
- the surface light source device 204 includes a surface light-emitting light guide plate 4, a light reflection sheet 5, a light guide member 506, a first light source 208, and a second light source 209. Further, the surface light source device 204 includes a component having the function of the light guide member 506. 14, components that are the same as or correspond to the components shown in FIG. 10 (Embodiment 3) are assigned the same reference numerals.
- the liquid crystal display device 104 is a transmissive display device.
- the end surface 561d of the light guide member 506 is formed of a diffuse reflection surface.
- the liquid crystal display device 104 is the same as that of the third embodiment except for the above differences.
- the fifth embodiment is different from the first and second embodiments in the components of the first light source 208 and the second light source 309, and is different in that the light guide member has a diffuse reflection surface. With respect to the other components, the fifth embodiment is the same as the first and second embodiments. Also in the fifth embodiment, the modes of FIGS. 4, 6 and 7 other than the mode of FIG. 1 of the first embodiment can be taken. Also in the fifth embodiment, the form of FIG. 13 other than the form of FIG. 12 of the fourth embodiment can be taken.
- the diffuse reflection surface provided on the end surface 561d of the fifth embodiment is provided on the end surface 61d in FIG. 1, provided on the reflection surface 183a in FIG. 4, provided on the end surface 171c in FIG. 6, and applied to the end surface 141d in FIG. 8, provided on the end surface 61 d in FIG. 8, provided on the end surface 61 d in FIG. 10, provided on the end surface 461 d in FIG. 12, and provided on the reflecting surface 481 c in FIG. 13.
- the first light source 208 uses an LED element that emits a blue-green first light beam 281. Blue-green light is light obtained by mixing blue light and green light.
- the second light source 309 uses a laser light emitting element that emits a red second light beam 391.
- the wavelength width of the laser beam is narrow. That is, the laser beam has high color purity. For this reason, the red color purity is improved by using a laser emitting element of red light. That is, the color reproduction range of the display color is widened.
- the liquid crystal display device 102 includes a liquid crystal panel driving unit 12 and a light source driving unit 13.
- the liquid crystal panel drive unit 12 drives the liquid crystal panel 1.
- the light source driving unit 13 drives the first light source and the second light source.
- the first light source is the first light source 208.
- the second light source is a laser light source 309.
- the control unit 11 controls the operation of the liquid crystal panel driving unit 12 and controls the operation of the light source driving unit 13.
- the control unit 11 performs image processing on the input video signal and generates a liquid crystal panel control signal and a light source control signal.
- the control unit 11 supplies a liquid crystal panel control signal to the liquid crystal panel drive unit 12.
- control unit 11 supplies a light source control signal to the light source driving unit 13.
- the liquid crystal panel drive unit 12 drives the liquid crystal panel 1 based on the liquid crystal panel control signal.
- the light source driving unit 13 drives the first light source 208 and the second light source 309 based on the light source control signal.
- the second light source 309 is disposed to face the end surface 561a of the light guide member 506.
- the end surface 561a is an end surface of the light guide member 506 on the + x axis direction side.
- the end surface 561a is a light incident end surface.
- the light guide member 506 is disposed in parallel to the display surface 1 a of the liquid crystal panel 1.
- the second light source 309 has a plurality of laser light emitting elements arranged at equal intervals in the y-axis direction.
- the first light source 208 emits a first light beam 281 (for example, blue-green).
- the second light source 309 emits a second light ray 391 (for example, red).
- the first light beam 281 having a wide angular intensity distribution emitted from the first light source 18 travels in a substantially + x-axis direction toward the light incident surface 41 a of the surface light-emitting light-guiding plate 15.
- the angular intensity distribution represents the relationship between the angle and the intensity with respect to the emission direction.
- the second light beam 391 emitted from the second light source 309 enters the light incident end 561a of the light guide member 506, repeats total reflection at the interface between the light guide member 506 and the air layer, and passes through the light guide member 506.
- the angular intensity distribution of the second light ray 391 is stored. Therefore, the angular intensity distribution of the second light ray 391 reaching the diffuse reflection surface 561d is equal to the angular intensity distribution of the second light ray 391 when emitted from the second light source 309, and the full width at half maximum of each angular intensity distribution is the same. Is an angle.
- the full width at half maximum of the angular intensity distribution is, for example, 5 °.
- the second light ray 391 changes the traveling direction from the ⁇ x axis direction to the + z axis direction at the end surface 561c of the light guide member 506. Thereafter, the second light ray 391 is reflected by the diffuse reflection surface 561d and changes the traveling direction in the direction of the light incident surface 41a (substantially + x-axis direction) of the surface light-emitting light guide plate 4.
- the full width at half maximum of the angular intensity distribution of the second light ray 391 is increased.
- the same effect as in the third embodiment can be obtained.
- different types of light sources having different angular intensity distributions are employed.
- the first light source 208 employs an LED element
- the second light source 309 employs a laser light emitting element.
- the light guide member 506 can match the angular intensity distribution of the light source having a narrow angular intensity distribution with the angular intensity distribution of the other light source.
- the light guide member 506 has an in-plane luminance distribution of the surface-emitting light guide plate 400 generated by the first light beam 281 and an in-plane luminance distribution of the surface-emitting light guide plate 400 generated by the second light beam 391. The difference can be suppressed.
- the liquid crystal display device 104 can suppress uneven color.
- the color reproduction range can be expanded by generating white light using at least one kind of light source having high single color.
- the liquid crystal display device employs a plurality of light sources having different angular intensity distributions.
- a laser light emitting device that is very excellent in monochromaticity has high directivity. Therefore, the fifth embodiment is effective as a configuration for extending the color reproduction range.
- Embodiment 5 The purpose of Embodiment 5 is to match the angular intensity distributions of different types of light sources having different angular intensity distributions. Therefore, in Embodiment 5, the same effect can be obtained by providing the diffusion structure provided on the end surface 561d of the light guide member 506 on the other reflection surface on the optical path of the second light ray 391. However, the angular intensity distribution of the second light ray 391 is widened by the diffusion structure. For this reason, when the diffusion structure is provided in the vicinity of the light incident surface 41 a of the surface light emitting light guide plate 4, it is possible to suppress a decrease in the amount of the second light beam 391 incident on the surface light emitting light guide plate 4.
- the diffusing structure is provided in the vicinity of the light incident surface 41 a of the surface light-emitting light guide plate 4.
- the diffusion structure is a structure for changing the traveling direction of each light beam randomly. In other words, the diffusion structure is to make light with less directivity.
- the diffusion structure may be provided in a region where the second light ray 391 exits from the light guide member 506 on the end surface 561e as shown in FIG.
- a diffusion element 600 may be provided between the light guide member 506 and the surface light-emitting light guide plate 4.
- the light guide member 506 may include the diffusing element 600 on the surface of the emission surface.
- the light guide member 506 may include a diffusion element 600 inside the light guide member 506 in the vicinity of the exit surface.
- the surface light-emitting light guide plate 4 may include a diffusion element 600 on the surface of the light incident surface 41a.
- the surface light-emitting light guide plate 4 may include a diffusing element 600 inside the surface light-emitting light guide plate 4 in the vicinity of the light incident surface 41a.
- the end surface 561d may have an arcuate mirror configuration. Further, the end surface 561d can have the same shape as the cylindrical mirror 1202 shown in FIG. 24, the light reflecting member 1302 shown in FIG. 26, and the light reflecting mirror 1402 shown in FIG.
- the light reflecting member 1302 has a light reflecting surface in which convex portions and concave portions are alternately continued.
- the light reflecting mirror 1402 has a continuous light reflecting surface having a polygonal cross section.
- the diffusion structure is formed on the end surface 561e, the light incident surface 41a, and the surface of the diffusion element 600.
- the diffusion structure may be a structure in which a plurality of fine concave lenses are formed.
- the diffusion structure may be a structure in which a plurality of fine convex lenses are formed.
- the diffusion structure may be a structure in which a plurality of fine pyramid shapes are formed.
- corrugated shape was formed by the blast process may be sufficient.
- particles having a refractive index different from that of the surrounding material may be attached by painting.
- the diffusion element 600 may be an element that includes particles having a refractive index different from that of the surrounding material.
- FIG. 18 is a cross-sectional view schematically showing a configuration of a liquid crystal display device 3001 (including a surface light source device 1100) according to the sixth embodiment.
- the surface light source device 1100 includes a surface light-emitting light guide plate 1015, a light reflection sheet 1017, a diffuse reflection member 1102, a first light source 1018, and a second light source 1101.
- the surface light source device 1110 includes a surface emitting light guide plate 1015, a light reflection sheet 1017, a diffuse reflection member 1112, a first light source 1018, and a second light source 1111.
- 19 is a schematic plan view of the surface light source device 1100 shown in FIG.
- FIG. 20 shows the surface light source device 1100 shown in FIG. 4 is a schematic rear view of the liquid crystal display device 3001 as viewed from the back side ( ⁇ z-axis direction).
- the liquid crystal display device 3001 is a transmissive liquid crystal display device including a liquid crystal display element (liquid crystal panel) 1011.
- the liquid crystal display element (liquid crystal panel) 1011 has a rectangular display surface 1011a and a back surface 1011b on the opposite side.
- the coordinate axes of the xyz orthogonal coordinate system are shown in each figure.
- the short side direction of the display surface 1011a of the liquid crystal panel 1011 is the y-axis direction (direction perpendicular to the paper surface on which FIG. 18 is drawn)
- the long side direction of the display surface 1011a of the liquid crystal panel 1011 is the x-axis.
- a direction perpendicular to the xy plane is a z-axis direction (up and down direction in FIG. 18).
- the direction from left to right is the positive x-axis direction (+ x-axis direction), and the opposite direction is the negative x-axis direction ( ⁇ x-axis direction).
- the direction from the front of the drawing of FIG. 18 toward the drawing is the positive direction of the y axis (+ y axis direction), and the opposite direction is the negative direction of the y axis ( ⁇ y axis direction).
- the direction from the bottom to the top is the positive z-axis direction (+ z-axis direction), and the opposite direction is the negative z-axis direction ( ⁇ z-axis direction).
- a liquid crystal display device 3001 of Embodiment 6 includes a transmissive liquid crystal panel 1011, a first optical sheet 1012, a second optical sheet 1013, a second optical sheet 1013, A surface light source device 1100 as a backlight unit that irradiates light to the back surface 1011b of the liquid crystal panel 1011 through the first optical sheet 1012 is provided.
- These components 1011, 1012, 1013, 1100 are arranged in order in the ⁇ z-axis direction.
- the liquid crystal display element 1 of the first to fifth embodiments is the same as the liquid crystal display element 1011 of the sixth embodiment.
- the first optical sheet 2 in the first to fifth embodiments is the same as the first optical sheet 1012 in the sixth embodiment.
- the second optical sheet 3 in the first to fifth embodiments is the same as the second optical sheet 1013 in the sixth embodiment.
- the surface-emitting light guide plate 4 of the first to fifth embodiments is a part of the constituent elements other than the constituent elements of the mixed region 1015e of the surface-emitting light guide plate in the surface-emitting light guide plate 1015 of the sixth embodiment. It is the same as the surface light-emitting light guide plate.
- the light reflecting sheet 5 of the first to fifth embodiments is the same as the light reflecting sheet 1017 of the sixth embodiment.
- the display surface 1011a of the liquid crystal panel 1011 is a surface parallel to the xy plane.
- the liquid crystal layer of the liquid crystal panel 1011 has a planar structure spreading in a direction parallel to the xy plane.
- the display surface 1011a of the liquid crystal panel 1011 is usually rectangular, and two adjacent sides of the display surface 1011a (in Embodiment 6, the short side in the y-axis direction and the long side in the x-axis direction) are orthogonal to each other. Yes.
- the shape of the display surface 1011a may be another shape.
- the surface light source device 1100 includes a thin plate-like surface light-emitting light guide plate 1015, a first light source 1018, a second light source 1101, and a diffuse reflection member 1102.
- the diffuse reflection member 1102 has a function as an optical path changing member.
- the first light source 1018 emits the first light beam L11 from the light emitting unit.
- the light emitting unit of the first light source 1018 is disposed to face the light incident surface (side surface) 1015c of the surface light emitting light guide plate 1015.
- the first light source 1018 is, for example, a light source device in which a plurality of light emitting diode (LED) elements are arranged at equal intervals in the y-axis direction.
- the first light source 1018 is desirably arranged within the range of the length of the light incident surface 1015c in the z-axis direction.
- the range of the length of the light incident surface 1015c in the z-axis direction is the range of the thickness of the surface light-emitting light guide plate 1015.
- the first light beam L11 emitted from the first light source 1018 is directly incident on the light incident surface 1015c of the surface light-emitting light-guiding plate 1015.
- the first light beam L11 may be incident on the light incident surface 1015c via another optical element such as a lens.
- the second light source 1101 is disposed on the back surface 1015b side ( ⁇ z-axis direction) of the surface-emitting light guide plate 1015.
- the back surface 1015b side is a position facing the light emitting surface 1015a of the surface light emitting light guide plate 1015.
- the light emitting surface 1015a is a light emitting surface of the surface emitting light guide plate 1015.
- the second light source 1101 is, for example, a light source device in which a plurality of laser light emitting elements are arranged at equal intervals in the y-axis direction.
- the light emitting unit that emits the second light beam L12 of the second light source 1101 is disposed to face the diffused light reflecting surface 1102a of the diffuse reflecting member 1102.
- the diffused light reflecting surface 1102a of the diffuse reflecting member 1102 is disposed to face the light incident surface 1015c of the surface emitting light guide plate 1015.
- the diffused light reflecting surface 1102a of the diffuse reflecting member 1102 has a plurality of messy minute undulating shapes (uneven shape). Therefore, the light beam incident on the diffused light reflecting surface 1102a of the diffusely reflecting member 1102 changes its traveling direction (propagating direction) to a direction toward the light incident surface 1015c of the surface emitting light guide plate 1015. Further, the light beam incident on the diffused light reflecting surface 1102a changes the traveling direction in a random manner. That is, the light beam incident on the diffused light reflecting surface 1102a is scattered and reflected by the diffused light reflecting surface 1102a.
- the diffuse light reflecting surface 1102a of the diffuse reflecting member 1102 is formed by forming a rough uneven shape on the surface of an acrylic resin (for example, PMMA (polymethyl methacrylate resin)) by blasting or the like, and depositing aluminum on the surface. is there.
- an acrylic resin for example, PMMA (polymethyl methacrylate resin)
- the configuration of the diffused light reflecting surface 1102a of the diffuse reflecting member 1102 is not limited to the above example.
- a resin such as polycarbonate having excellent processability or a metal may be used as the base material of the diffusely reflecting member 1102.
- another metal having a high reflectance such as silver or gold may be adopted.
- the diffused light reflecting surface 1102a of the diffuse reflecting member 1102 for example, a surface in which a plurality of beads having different sizes are coated on the surface of the base material and a metal film such as silver is provided on the surface may be adopted. Good.
- a reflection film in which a cell structure is provided in a polyester base material may be employed. In this case, high diffuse reflection performance can be obtained by optimizing the uneven structure on the surface and the bubble structure in the substrate.
- these diffuse reflection members 1102 are simple and inexpensive members, and a high image quality improvement effect can be obtained even with a simple structure and low cost.
- the surface emitting light guide plate 1015 has a light emitting surface 1015a, a back surface 1015b opposite to the light emitting surface 1015a, and a plurality of side surfaces (for example, 1015c, 1015d, etc.).
- the side surface is an elongated surface connecting the side of the light emitting surface 1015a and the side of the back surface 1015b.
- the surface-emitting light guide plate 1015 is a translucent optical member.
- the surface-emitting light guide plate 1015 includes a plurality of micro optical elements 1016 arranged on the back surface 1015b.
- the surface light source device 1100 includes a light reflecting sheet 1017.
- the light reflecting sheet 1017 is disposed so as to face the back surface 1015b of the surface emitting light guide plate 1015.
- the micro optical element 1016 has a function of directing light incident from the light incident surface 1015c toward the light emitting surface 1015a of the surface light emitting light guide plate 1015.
- the light incident surface 1015 c is a side surface of the surface emitting light guide plate 1015.
- the region having a large area occupied by the micro optical element 1016 is, for example, a region where the micro optical element 1016 has a large diameter, or a region where the arrangement density of the micro optical elements 1016 is high.
- the arrangement, number, and shape of the micro optical elements 1016 are increased so that the area occupied by the micro optical elements 1016 on the back surface 1015b of the surface light emitting light guide plate 1015 increases as the distance from the light incident surface 1015c of the surface light emitting light guide plate 1015 increases. It is desirable to decide.
- the arrangement, number, and shape of the micro optical elements 1016 shown in FIGS. 18 and 20 are merely examples. For example, as in the micro optical element 1016a shown in FIG. 21, the arrangement density of the micro optical elements 1016 is increased as the distance from the light incident surface 1015c of the surface emitting light guide plate 1015 increases. It is good also as a shape.
- the surface-emitting light guide plate 1015 is disposed so that the light-emitting surface 1015 a is parallel to the display surface 1011 a of the liquid crystal panel 1011.
- the surface emitting light guide plate 1015 includes a mixed region 1015e.
- the mixed region 1015e is a region having a predetermined length (for example, 10 mm) from the light incident surface 1015c toward the center of the surface emitting light guide plate 1015.
- the center of the surface light-emitting light guide plate 1015 from the light incident surface 1015c is the + x-axis direction in FIG.
- the surface-emitting light guide plate 1015 has no optical structure on the front surface and the back surface, and faces the air layer.
- the mixed region 1015e from the light incident surface 1015c travels (propagates) in the + x-axis direction while being totally reflected at the interface with the air layer.
- the interface with the air layer is a surface of the mixed region on the light emitting surface 1015a side and a surface of the mixed region on the back surface 1015b side.
- the surface-emitting light guide plate 1015 has a micro optical element 1016 on the back surface 1015b of the region 1015f excluding the mixed region 1015e.
- a region 1015f excluding the mixed region 1015e is a light guide region.
- the back surface 1015 b is a surface on the opposite side to the liquid crystal panel 1011.
- the micro optical element 1016 has a function of changing the mixed light beam L13 into the illumination light L14.
- the mixed light beam L13 is light that propagates inside the surface-emitting light guide plate 1015.
- the illumination light L14 is light emitted in a substantially + z-axis direction.
- the illumination light L14 is emitted from the surface light-emitting light guide plate 1015 toward the back surface 1011b of the liquid crystal panel 1011.
- the surface emitting light guide plate 1015 is a component made of a transparent material such as acrylic resin (for example, PMMA).
- the surface-emitting light guide plate 1015 is a thin plate member having a thickness in the z-axis direction of 4 mm, for example.
- a plurality of micro optical elements 1016 are provided on the back surface 1015 b of the surface emitting light guide plate 1015.
- the micro optical element 1016 is a hemispherical convex lens-shaped element protruding in the ⁇ z-axis direction.
- the mixed light beam L13 is totally reflected at the interface between the surface emitting light guide plate 1015 and the air layer.
- the mixed light beam L13 propagates inside the surface-emitting light guide plate 1015.
- the mixed light beam L13 travels in the + x-axis direction while repeating reflection.
- the mixed light beam L13 enters the micro optical element 1016, it is reflected by the curved surface of the micro optical element 1016 and changes the traveling direction.
- the traveling direction of the mixed light beam L13 changes, a light beam that does not satisfy the total reflection condition at the interface between the surface of the surface emitting light guide plate 1015 and the air layer is generated in the mixed light beam L13.
- the light beam does not satisfy the total reflection condition, the light beam is emitted from the light emitting surface 1015a of the surface light emitting light guide plate 1015 toward the back surface 1011b of the liquid crystal panel 1011.
- the first light beam L11 and the second light beam L12 are incident on the light incident surface 1015c of the surface emitting light guide plate 1015.
- the first light beam L11 is emitted light from the first light source 1018.
- the second light beam L12 is emitted light from the second light source 1101.
- the first light source 1018 emits the first light beam L11 toward the light incident surface 1015c.
- the second light source 1101 is disposed on the back surface 1015b side from the first light source 1018.
- the second light source 1101 emits a second light beam L12 having an angular intensity distribution narrower than that of the first light beam L11.
- the diffuse reflection member 1102 has a function of guiding the second light beam L12 emitted from the second light source 1101 to the light incident surface 1015c.
- the diffuse reflection member 1102 has a function as an optical path changing member. Further, the diffuse reflection member 1102 can be configured to have a function of bringing the size of the cross section of the second light ray L12 on the light incident surface 1015c closer to the size of the cross section of the first light ray L11 on the light incident surface 1015c. .
- the size of the cross section is the length of the light incident surface 1015c in the z-axis direction, that is, the thickness of the surface emitting light guide plate 1015. Further, both the first light beam L11 emitted from the first light source 1018 and the second light beam L12 emitted from the second light source 1101 enter the surface light-emitting light guide plate 1015 from the light incident surface 1015c.
- the diffuse reflection member 1102 changes the angular intensity distribution of the second light beam L12 just before entering the light incident surface 1015c to the angular intensity distribution of the first light beam L11 just before entering the light incident surface 1015c. It has a function of changing the angular intensity distribution of the second light ray L12 so as to approach.
- the diffuse reflection member 1102 has the function of changing the angular intensity distribution of the second light ray L12 and the function of changing the traveling direction of the second light ray L12.
- the diffuse reflection member 1102 as the optical path changing member guides the second light ray L12 emitted from the second light source 1101 to the light incident surface 1015c.
- the first light beam L11 emitted from the first light source 1018 is, for example, a blue-green light beam.
- the second light beam L12 emitted from the second light source 1101 is, for example, a red light beam.
- the first light beam L11 is emitted from the first light source 1018 toward the light incident surface 1015c of the surface light-emitting light-guiding plate 1015 in the approximately + x-axis direction (right direction in FIG. 18).
- the second light beam L12 is emitted from the second light source 1101 in the approximately + z-axis direction, diffusely reflected by the light reflecting surface 1102a of the diffusive reflecting member 1102, and then the light incident surface of the surface-emitting light guide plate 1015 in the approximately + x-axis direction.
- Both the first light beam L11 and the second light beam L12 are incident on the light incident surface 1015c of the surface emitting light guide plate 1015.
- the first light beam L11 and the second light beam L12 are mixed in the mixed region 1015e to become a mixed light beam L13.
- the mixed region 1015e is disposed in the vicinity of the light incident surface 1015c in the surface-emitting light guide plate 1015.
- the mixed light L13 is, for example, a white light.
- the micro optical element 1016 has a function of converting the mixed light beam L13 into illumination light L14.
- the micro optical element 1016 is provided on the back surface 1015 b of the surface emitting light guide plate 1015.
- the illumination light L14 travels substantially in the + z-axis direction and travels toward the back surface 1011b of the liquid crystal panel 1011.
- the illumination light L14 passes through the second optical sheet 1013 and the first optical sheet 1012 and is irradiated on the back surface 1011b of the liquid crystal panel 1011.
- the first optical sheet 1012 has a function of directing the illumination light L14 toward the back surface 1011b of the liquid crystal panel 1011.
- the second optical sheet 1013 has a function of suppressing optical influences such as fine illumination unevenness due to the illumination light L14.
- the illumination light L14 is illumination light emitted from the light emitting surface 1015a of the surface emitting light guide plate 1015.
- the diffuse reflection member 1102 is inclined with respect to a direction (z-axis direction in FIG. 18) parallel to the light incident surface 1015c of the surface light-emitting light-guiding plate 1015. . Further, the diffuse reflection member 1102 is disposed so as to be inclined so that the diffuse light reflection surface 1102a faces the ⁇ z-axis direction.
- the reason for the inclined arrangement is as follows. The first reason is that the light L12 emitted from the second light source 1101 efficiently enters the diffused light reflecting surface 1102a with respect to the arrangement position of the second light source 1101 provided on the ⁇ z-axis direction side of the surface-emitting light guide plate 1015. It is to be.
- the second reason is that light emitted from the diffused light reflecting surface 1102a is efficiently incident on the light incident surface 1015c of the surface emitting light guide plate 1015. This is because the inclination of the diffuse reflection member 1102 can achieve both of the above two reasons.
- the positional relationship and arrangement angle between the second light source 1101 and the diffused light reflecting surface 1102a of the diffuse reflecting member 1102 and the positional relation and arrangement angle between the diffuse reflecting member 1102 and the surface emitting light guide plate 1015 are emitted from the second light source 1101.
- the angular intensity distribution of the second light beam L12, the size (diameter) of the second light beam L12, the diffusion characteristics of the diffuse reflection member 1102, the thickness of the surface light-emitting light guide plate 1015, and the like are set. Therefore, when each condition is different, it is necessary to optimize the positional relationship and the arrangement angle of each member.
- the arrangement angle is a rotation angle about the y axis when each member is arranged.
- the arrangement density of the micro optical elements 1016 changes at a position in the xy plane above the surface-emitting light guide plate 1015.
- the arrangement density is the number of micro optical elements 1016 per unit area or the area (size) occupied by the micro optical elements 1016 per unit area.
- the in-plane luminance distribution of the illumination light L14 can be controlled.
- the illumination light L14 is light emitted from the surface emitting light guide plate 1015.
- the in-plane luminance distribution is a distribution indicating the level of luminance with respect to a position expressed in two dimensions on an arbitrary plane.
- the in-plane here refers to the display surface.
- the curvature radius of the convex surface of the micro optical element 1016 is, for example, about 0.15 mm, and the maximum height of the micro optical element 1016 is about 0.005 mm.
- the refractive index of the micro optical element 1016 is about 1.49.
- the material of the surface emitting light guide plate 1015 and the material of the micro optical element 1016 can be acrylic resin.
- the material of the surface-emitting light guide plate 1015 and the material of the micro optical element 1016 are not limited to acrylic resin.
- a material of the surface light-emitting light guide plate 1015 and the micro optical element 1016 a material having good light transmittance and excellent molding processability can be adopted.
- acrylic resin instead of acrylic resin, another resin material such as polycarbonate resin can be employed.
- the thickness of the surface emitting light guide plate 1015 is not limited to 4 mm. In consideration of the reduction in thickness and weight of the liquid crystal display device 3001, it is desirable to employ the surface emitting light guide plate 1015 having a small thickness.
- the shape of the micro optical element 1016 is not limited to a convex lens shape.
- the micro optical element 1016 may have any shape as long as the micro optical element 1016 reflects the mixed light beam L13 in the substantially + z-axis direction and emits the mixed light beam L13 toward the back surface 1011b of the liquid crystal panel 1011.
- the mixed light beam L13 is light that travels in the x-axis direction inside the surface-emitting light guide plate 1015. If it has this function, the shape of the micro optical element 1016 may be another shape.
- the micro optical element 1016 may have a prism shape or a random uneven pattern.
- the width in the zx plane of the diffuse reflection member 1102 is 1.5 mm.
- the second light beam L12 emitted from the laser light emitting element in the second light source 1101 has a full width at half maximum of 5 ° in the angular intensity distribution. Since the second light ray L12 has high directivity, the width of the second light ray L12 in the zx plane is large even when freely propagating through the distance between the second light source 1101 and the diffuse reflection member 1102. Does not spread.
- free propagation means that light travels in the air without being incident on a substance such as an optical element. Therefore, it is possible to suppress the optical loss of the second light beam L12 due to the reduction in the width of the diffuse reflection member 1102 in the zx plane. Further, when the diffuse reflection member 1102 is downsized, the thickness of the surface emitting light guide plate 1015 can be reduced, and the depth of the liquid crystal display device can be reduced.
- the first light beam L11 When an LED element is used as the first light source 1018, the first light beam L11 generally has a wide divergence angle.
- the angular intensity distribution of the first light ray L11 is a full width at half maximum of 60 °.
- the first light beam L11 emitted from the first light source 1018 is incident on the light incident surface 1015c of the surface emitting light guide plate 1015 without changing the angular intensity distribution.
- the second light beam L12 has high directivity.
- the angular intensity distribution of the second light ray L12 has a full width at half maximum of 5 °.
- the second light beam L12 emitted from the second light source 1101 is diffused by the diffuse reflection member 1102.
- the second light ray L12 is incident on the light incident surface 1015c of the surface light-emitting light guide plate 1015 after the angle of the angular intensity distribution is expanded to an angle substantially equal to the angular intensity distribution of the first light ray L11 emitted from the first light source 1018.
- the micro optical element 1016 is disposed in a region 1015f in the back surface of the surface light-emitting light guide plate 1015.
- the region 1015f is a region from a position separated from the light incident surface 1015c by an arbitrary length to the side surface 1015d.
- the arbitrary length is the length of the mixed region 1015e in the x-axis direction.
- the micro optical element 1016 is provided on the back surface 1015 b of the surface emitting light guide plate 1015.
- a region 1015f where the micro optical element 1016 is disposed on the back surface 1015b of the surface light-emitting light guide plate 1015 is substantially the same as the effective image display region of the liquid crystal panel 1011. However, it may be somewhat larger than the effective image display area of the liquid crystal panel 1011.
- the center position of the area 1015f where the micro optical element 1016 is arranged on the back surface 1015b of the surface light-emitting light guide plate 1015 is the same as the center position of the effective image display area (area parallel to the xy plane) of the liquid crystal panel 1011, or It is desirable that the liquid crystal panel 1011 be positioned near the center position of the effective image display area.
- the illumination light L14 emitted from the light emitting surface 1015a of the surface emitting light guide plate 1015 is illuminated over the entire effective image display area of the liquid crystal panel 1011.
- a person who views the display surface 1011a of the liquid crystal panel 1011 can see an image with no image defect in the display surface 1011a.
- the effective image display area is a range where an image is actually displayed.
- the image defect here means that when the center position of the effective image area of the liquid crystal panel 1011 and the center position of the area 1015f of the surface light-emitting light guide plate 1015 are different, uniform light is emitted over the entire effective image display area of the liquid crystal panel 1011. It means a state where it is not irradiated and displayed.
- the effective image display area of the liquid crystal panel 1011 is disposed above the mixed area 1015e of the surface light-emitting light guide plate 1015, light is not emitted in the direction of the liquid crystal panel in this area (mixed area 1015e), so that an image is displayed. Can not.
- the light reflecting sheet 1017 is disposed so as to face the back surface 1015b of the surface emitting light guide plate 1015.
- the light emitted from the back surface 1015b of the surface emitting light guide plate 1015 is reflected by the light reflecting sheet 1017, enters the surface emitting light guide plate 1015 from the back surface 1015b, is emitted from the light emitting surface 1015a of the surface emitting light guide plate 1015, and is illuminated.
- the back surface 1011b of the liquid crystal panel 1011 is illuminated as L14.
- the light reflecting sheet 1017 for example, a light reflecting sheet based on a resin such as polyethylene terephthalate can be used. Further, as the light reflecting sheet 1017, a light reflecting sheet obtained by depositing metal on the surface of the substrate may be used.
- FIG. 22 is a block diagram illustrating a configuration of a control system of the liquid crystal display device 3001 according to the sixth embodiment.
- the liquid crystal display device 3001 includes a liquid crystal panel 1011, a liquid crystal panel driving unit 1022, a first light source 1018, a second light source 1101, a light source driving unit 1023, and a control unit 1021. is doing.
- the liquid crystal panel driving unit 1022 drives the liquid crystal panel 1011.
- the light source driving unit 1023 drives the first light source 1018 and the second light source 1101.
- the control unit 1021 controls the operation of the liquid crystal panel driving unit 1022 and the operation of the light source driving unit 1023.
- the control unit 1021 performs image processing on the input video signal S30.
- the control unit 1021 generates a liquid crystal panel control signal S31 based on the input video signal S30.
- the control unit 1021 supplies the liquid crystal panel control signal S31 to the liquid crystal panel driving unit 1022.
- the control unit 1021 generates a light source control signal S32 based on the input video signal S30.
- the control unit 1021 supplies the light source control signal S32 to the light source driving unit 1023.
- the liquid crystal panel driving unit 1022 drives the liquid crystal panel 1011 based on the liquid crystal panel control signal S31 and causes the liquid crystal panel 1011 to display an image.
- the liquid crystal panel driving unit 1022 changes the light transmittance of the liquid crystal layer of the liquid crystal panel 1011 in units of pixels based on the liquid crystal panel control signal S31 received from the control unit 1021.
- Each pixel of the liquid crystal panel 1011 includes, for example, three subpixels (first to third subpixels) of red (R), green (G), and blue (B).
- a red subpixel is a first subpixel
- a green subpixel is a second subpixel
- a blue subpixel is a third subpixel.
- the first subpixel includes a color filter that transmits only red light
- the second subpixel includes a color filter that transmits only green light
- the third subpixel includes blue light.
- a color filter that only transmits light is a color filter that only transmits light.
- the control unit 1021 causes the liquid crystal panel driving unit 1022 to display the color image on the liquid crystal panel 1011 by controlling the light transmittance of each sub-pixel of the liquid crystal panel 1011.
- the liquid crystal panel 1011 creates image light by spatially modulating the illumination light L14 incident from the surface light-emitting light guide plate 1015, and emits the image light from the display surface 1011a.
- the image light is light having image information.
- the light source driver 1023 drives the first light source 1018 and the second light source 1101 based on the light source control signal S32, and adjusts the luminance of the image displayed on the liquid crystal panel 1011.
- the difference in the in-plane luminance distribution becomes uneven color on the display surface 1011a. Will appear.
- the first light source L11 and the second light source L12 have different angular intensity distributions, and the first light source 1018 and the second light source 1101 emit light of different colors. That is, the different color rays (the first ray L11 and the second ray L12) have different angular intensity distributions.
- the very narrow angular intensity distribution of the second light beam L12 is expanded by the diffuse reflection member 1102, and is close to the angular intensity distribution of the first light beam L11.
- the second light beam L12 is a light beam emitted from the second light source 1101 using a laser light emitting element.
- the first light beam L11 is a light beam emitted from the first light source 1018 using an LED element.
- Both the first light beam L11 and the second light beam L12 incident on the light incident surface 1015c of the surface light-emitting light guide plate 1015 are mixed and propagated through the mixed region 1015e to become white light L13. Thereafter, the white light L13 is emitted from the surface light-emitting light guide plate 1015 toward the liquid crystal panel 1011 by the micro optical element 1016.
- the first light ray L11 is a cyan light ray.
- the second light ray L12 is a red light ray.
- the mixed region 1015e is provided in the vicinity of the light incident surface 1015c of the surface emitting light guide plate 1015.
- the light beams of the respective colors are incident on the surface light-emitting light guide plate 1015 with an equal angular intensity distribution. Accordingly, the illumination light L14 emitted from the surface light-emitting light guide plate 1015 can emit white planar light having no color unevenness in the xy plane.
- the control unit 1021 can control the light source driving unit 1023 to adjust the ratio between the luminance of the first light beam L11 and the luminance of the second light beam L12.
- the width of the transmission wavelength band of the color filter of the liquid crystal panel 1011 must be set narrow.
- the amount of light transmitted through the color filter decreases.
- fluorescent lamps that have been used conventionally have an emission spectrum peak in the red region in the orange wavelength region.
- a white LED using a yellow phosphor also has an emission spectrum peak in the red region in the orange wavelength region. That is, the wavelength peak in the red region is in an orange region that is shifted from the red region.
- the color purity is to be increased in red, the amount of transmitted light is extremely reduced and the luminance is significantly reduced.
- the first light source 1018 has an LED element that emits a blue-green first light beam L11.
- the blue-green first light beam L11 mixes blue and green light.
- the second light source 1101 has a single color laser light emitting element that emits a red second light beam L12.
- the spectrum of the second light ray L12 has a peak in the vicinity of 640 nm, for example.
- the wavelength width of the second light beam L12 is as narrow as 1 nm in full width at half maximum, and the color purity is high.
- the second light source 1101 can improve the red color purity by using the red laser light emitting element. That is, the liquid crystal display device 3001 can widen the color reproduction range of display colors.
- the present invention is not limited to this.
- the second light source 1101 uses a red laser light emitting element on the shorter wavelength side, the visibility with respect to the wavelength increases. For this reason, it becomes possible to improve the ratio of luminance / input power, and the power consumption can be further reduced. Further, by using a longer wavelength red laser light emitting element, it is possible to widen the color reproduction range and provide a vivid image.
- a laser light-emitting element that has a very narrow spectral width and can improve color purity has a very narrow angular intensity distribution.
- the second light beam L12 passes through the diffuse reflector 1102, so that the angular intensity distribution of the second light beam L12 becomes the angular intensity distribution of the first light beam L11. Can be expanded equally. For this reason, a white surface light source without color unevenness is obtained.
- the second light beam L12 is a laser beam emitted from the second light source 1101 formed of a laser element.
- the first light beam L11 is an LED light beam emitted from the first light source 1018 configured by LED elements.
- the illumination light L14 may be reflected by the first optical sheet 1012, the second optical sheet 1013, etc., and travel in the ⁇ z-axis direction.
- the illumination light L14 is light emitted from the surface emitting light guide plate 1015 toward the liquid crystal panel 1011. In order to realize high brightness and low power consumption, it is necessary to use the reflected light as illumination light for the liquid crystal panel 1011 again.
- the liquid crystal display device 3001 according to Embodiment 6 includes a light reflecting sheet 1017 on the surface emitting light guide plate 1015 on the ⁇ z-axis direction side.
- the light reflecting sheet 1017 directs light traveling in the approximately ⁇ z axis direction in the approximately + z axis direction. As a result, the liquid crystal display device 3001 can efficiently use light.
- ⁇ 6-2 Operation of Embodiment 6
- the surface light source device 1100 When the surface light source device 1100 is turned on, light is emitted from each of the first light source 1018 and the second light source 1101.
- the first light ray L11 (for example, cyan) emitted from the first light source 1018 travels in a direction (substantially + x-axis direction) toward the light incident surface 1015c of the surface light-emitting light guide plate 1015.
- the second light ray L12 (for example, red) emitted from the second light source 1101 is irradiated on the diffused light reflecting surface 1102a of the light diffusing member 1102, and increases the full width at half maximum of the angular intensity distribution of the second light ray L12 to increase the traveling direction. Is changed to a direction (substantially + x-axis direction) toward the light incident surface 1015c of the surface light-emitting light-guiding plate 1015.
- the first light beam L11 and the second light beam L12 incident on the light incident surface 1015c of the surface light-emitting light-guiding plate 1015 are mixed and become white light by propagating through the mixed region 1015e. Thereafter, the first light beam L11 and the second light beam L12 are reflected by the micro optical element 1016 and reflected by the light reflecting sheet 1017, etc., and then the liquid crystal panel 1011 as the planar illumination light L14 from the light emitting surface 1015a of the surface light emitting light guide plate 1015. It is emitted toward The mixed region 1015e is provided in the vicinity of the light incident surface 1015c of the surface light-emitting light guide plate 1015.
- each color light beam (that is, the first light beam L11 and the second light beam L12) propagates in the surface light-emitting light guide plate 1015 with an equal angular intensity distribution. Therefore, the illumination light L14 emitted from the surface light-emitting light guide plate 1015 becomes substantially uniform white planar light having no color unevenness in a plane parallel to the xy plane.
- the control unit 1021 controls the light source driving unit 1023 to adjust the ratio between the intensity of the first light beam L11 and the intensity of the second light beam L12, thereby adjusting the luminance and color of the light emitting surface 1015a.
- the surface light source device 1100 of Embodiment 6 includes the first light source 1018, the second light source 1101, and the diffuse reflection member 1102. .
- the first light source 1018 is disposed at a position facing the light incident surface (side surface) 1015 c of the surface light-emitting light guide plate 1015.
- the second light source 1101 is disposed at a position closer to the back surface 1015 b than the light incident surface 1015 c of the surface emitting light guide plate 1015.
- the diffuse reflection member 1102 functions as an optical path changing member that guides the second light ray L12 to the light incident surface 1015c.
- the traveling direction of the second light ray L12 is directed to the light incident surface 1015c of the surface light-emitting light guide plate 1015 using the diffuse reflection member 1102 as the optical path changing member. It has changed to. Therefore, the thickness of the surface light-emitting light guide plate 1015 can be reduced as compared with the conventional configuration in which two types of light sources arranged in the thickness direction of the surface light-emitting light guide plate are arranged facing the light incident surface of the surface light-emitting light guide plate. .
- FIG. 18 shows a configuration in which the second light source 1101 is arranged closer to the back surface 1015b side ( ⁇ z-axis direction side) of the surface light-emitting light-guiding plate 1015 than the first light source 1018 is.
- the present invention is not limited to this.
- the second light source 1111 is disposed on the + z-axis direction side of the first light source 1018. That is, in the surface light source device 1110, the second light source 1111 is disposed on the front surface 1015a side of the surface light-emitting light guide plate 1015.
- the diffuse reflection member 1112 is disposed at an appropriate position on the + z-axis direction side of the first light source 1018. That is, in the surface light source device 1110, the diffuse reflection member 1112 is disposed at an appropriate position on the front side of the light incident surface 1015c with respect to the first light source 1018. Further, as shown in FIG. 50, a diffusing element 1120 may be provided between the diffusive reflecting member 1102 and the surface emitting light guide plate 1015.
- the surface light source device 1100 uses the angular intensity distribution of the second light beam L12 immediately before entering the light incident surface 1015c of the surface emitting light guide plate 1015 as the first light beam immediately before entering the light incident surface 1015c.
- a diffuse reflection member 1102 is provided in order to approach the angular intensity distribution of L11.
- the diffuse reflection member 1102 functions as an optical path changing member that changes the traveling direction and angular intensity distribution of the second light ray L12.
- the angular intensity distribution of the second light ray L12 is brought close to the angular intensity distribution of the first light ray L11 using the diffuse reflection member 1102 as the optical path changing member. It is increasing.
- the in-plane luminance distribution of the planar illumination light emitted from the light emitting surface 1015a through the surface emitting light guide plate 1015 by the first light ray L11 and the second light ray L12 similarly emitted through the surface emitting light guide plate 1015 are emitted.
- the difference from the in-plane luminance distribution of the planar illumination light emitted from the surface 1015a is suppressed, and the color unevenness of the surface light source device 1100 can be reduced.
- the thickness of the surface light-emitting light guide plate 1015 is reduced, so that the thickness can be reduced.
- the liquid crystal display device 3001 having the surface light source device 1100 of Embodiment 6 can reduce the color unevenness of the surface light source device 1100, the color unevenness on the display surface 1011a of the liquid crystal panel 1011 can be reduced and the image quality can be reduced. Can be improved.
- control unit 1021 causes the light source driving unit 1023 to adjust the luminance of the second light beam L12 and the luminance of the first light beam L11.
- the control unit 1021 adjusts the light emission amount of each light source based on the video signal S30. Thereby, the power consumption of the liquid crystal display device 3001 can be reduced.
- the local local temperature due to the heat generated by each light source can ease the rise. Thereby, the fall of the luminous efficiency of the light source by ambient temperature rise can be suppressed.
- the light emitted from the two light sources arranged at different positions is the short side surface (light incident surface 1015c) of the surface emitting light guide plate 1015.
- the structure which injects from is adopted.
- the arrangement of the first light source 1018 and the second light source 1101, the position of the diffuse reflection member 1102, the arrangement and shape of the micro optical elements 1016, the end face of the long side of the surface light-emitting light guide plate 1015 can It can also be an incident surface.
- the first light source 1018 and the second light source 1101 are configured separately.
- the light source driving unit 1023 can individually control the outputs of the first light source 1018 and the second light source 1101 based on the image signal S30. For this reason, power consumption can be reduced.
- the liquid crystal display device 3001 can reduce stray light and improve contrast. Note that stray light is light that travels outside the regular optical path in an optical device, and is harmful to a desired application.
- a liquid crystal display device 3001 of Embodiment 6 is configured such that the first light source 1018 includes a blue-green LED element, and the second light source 1101 includes a red laser light-emitting element.
- the present invention is not limited to this.
- the present invention can be applied to a case where at least one type of light source having a wide angular intensity distribution and at least one other type of light source having a narrow angular intensity distribution are provided. is there.
- the first light source 1018 may include a fluorescent lamp that emits blue-green light
- the second light source 1101 may include a red laser light emitting element to generate white.
- the first light source 1018 may include blue and red LED elements
- the second light source 1101 may include a green laser light emitting element to generate white.
- a green LED element can be used for the first light source 1018 and a blue laser light emitting element and a red laser light emitting element can be used for the second light source 1101.
- the surface light source device 1100 is used as the backlight unit of the liquid crystal display device 3001.
- the surface light source device may be used for other purposes such as illumination.
- FIG. 24 is a cross-sectional view schematically showing a configuration of a liquid crystal display device 3002 (including a surface light source device 1200) of Embodiment 7.
- the surface light source device 1200 includes a surface emitting light guide plate 1015, a light reflecting sheet 1017, a cylindrical mirror 1202, a first light source 1018, and a second light source 1201.
- the surface light source device 1300 includes a surface emitting light guide plate 1015, a light reflecting sheet 1017, a light reflecting member 1302, a first light source 1018, and a second light source 1301.
- the surface light source device 1400 includes a surface emitting light guide plate 1015, a light reflecting sheet 1017, a light reflecting mirror 1402, a first light source 1018, and a second light source 1401.
- the surface light source device 1500 includes a surface emitting light guide plate 1015, a light reflecting sheet 1017, a cylindrical mirror 1502, a light reflecting mirror 1503, a first light source 1018, and a second light source 1501.
- FIG. 25 is a perspective view schematically showing a configuration of a cylindrical mirror 1202 as a light reflecting member of the surface light source device 1200 shown in FIG. 24 and 25, the same reference numerals are given to the same or corresponding components as those shown in FIG.
- the liquid crystal display device 3002 and the surface light source device 1200 according to the seventh embodiment are provided with a second light source 1201 and a cylindrical mirror 1202 instead of the second light source 1101 and the diffuse reflection member 1102 in the sixth embodiment. This is different from the liquid crystal display device 3001 and the surface light source device 1100 of the sixth embodiment. Except for the points where the second light source 1201 and the cylindrical mirror 1202 are changed, the liquid crystal display device 3002 and the surface light source device 1200 of the seventh embodiment are the same as the liquid crystal display device 3001 and the surface light source device 1100 of the sixth embodiment. It is. Note that the second light source 1201 is different in arrangement from the second light source 1101, but the light source itself is the same without any difference.
- the first light source 1018 emits the first light beam L21.
- the first light ray L21 is, for example, blue-green.
- Second light source 1201 has the same configuration as second light source 1101 in the sixth embodiment.
- the second light source 1201 emits the second light beam L22.
- the second light ray L22 is, for example, red.
- the first light ray L21 travels in the substantially + x-axis direction from the first light source 1018 toward the light incident surface 1015c.
- the second light ray L22 travels in the + z axis direction from the second light source 1201. Thereafter, the second light beam L22 is reflected by the cylindrical mirror 1202, and changes its traveling direction in the substantially + x-axis direction.
- the cylindrical mirror 1202 can also be configured to have a function of bringing the size of the cross section of the second light beam L22 on the light incident surface 1015c closer to the size of the cross section of the first light beam L21 on the light incident surface 1015c.
- the size of the cross section is the length of the light incident surface 1015c in the z-axis direction, that is, the thickness of the surface emitting light guide plate 1015.
- Both the first light beam L21 and the second light beam L22 are incident on the light incident surface 1015c of the surface emitting light guide plate 1015.
- the first light beam L21 and the second light beam L22 are mixed in the mixed region 1015e to become a white mixed light beam L23.
- the mixed region 1015e is a region near the light incident surface 1015c in the surface light-emitting light guide plate 1015.
- the light reflecting surface 1202a of the cylindrical mirror 1202 has a circular arc shape in which a cross-sectional shape cut by a plane parallel to the zx plane is a concave shape at the light reflecting surface 1202a.
- the concave arc shape in the light reflecting surface 1202a is an arc shape inwardly directed to the light incident surface 1015c of the surface emitting light guide plate 1015.
- the cylindrical mirror 1202 is a first light reflecting member.
- the plane parallel to the zx plane is a plane orthogonal to the longitudinal direction (y-axis direction) of the light incident surface 1015c of the surface light-emitting light-guiding plate 1015.
- the light reflecting surface 1202a has a linear shape in which a cross-sectional shape cut by a plane parallel to the xy plane extends in the longitudinal direction (y-axis direction).
- the surface parallel to the xy plane is a surface parallel to the light emitting surface 1015a of the surface light emitting light guide plate 1015.
- the light reflecting surface 1202a is a concave surface in cross-sectional shape taken along a plane parallel to the zx plane.
- the light reflecting surface 1202a faces the light incident surface 1015c of the surface emitting light guide plate 1015. In the example shown in FIGS.
- the light reflecting surface 1202a of the cylindrical mirror 1202 is a 1 / n cylindrical light reflecting member obtained by dividing the cylinder into 1 / n by a plane parallel to the axial direction (y-axis direction).
- the surface 1202a is included.
- n is a value greater than 1.
- the cylinder includes a cylindrical shape having an elliptical cross section.
- a light reflecting surface 1202a that is a concave surface inside the cylindrical mirror 1202 is provided with a metal film layer that reflects light. The tangential direction at each position of the light reflecting surface 1202a changes depending on the position.
- the light reflecting surface 1202a of the cylindrical mirror 1202 is a concave reflecting surface, but it may be formed of a convex reflecting surface. An effect of diffusing light rays can be obtained even with a convex reflecting surface.
- the second light source 1201 is arranged to face the light reflecting surface 1202a of the cylindrical mirror 1202. Further, the light reflecting surface 1202a of the cylindrical mirror 1202 is disposed so as to face the light incident surface 1015c of the surface light-emitting light guide plate 1015.
- Cylindrical mirror 1202 in Embodiment 7 has an elliptical cylindrical shape, and its concave surface is used as light reflecting surface 1202a. An ellipse is a set of points whose sum of distances from two fixed points is constant.
- the base material of the cylindrical mirror 1202 is an acrylic resin (for example, PMMA), and the light reflecting surface 1202a is a surface on which aluminum is deposited.
- the material and shape which comprise the cylindrical mirror 1202 are not limited to this example.
- the liquid crystal display device 3002 of Embodiment 7 has a configuration in which light emitted from two light sources arranged at different positions enters from a short side surface (light incident surface 1015c) of the surface light-emitting light guide plate 1015.
- a short side surface light incident surface 1015c
- the long side surface of the surface emitting light guide plate 1015 can be used as the light incident surface.
- ⁇ 7-2 Operation of Embodiment 7
- the surface light source device 1200 When the surface light source device 1200 is turned on, light is emitted from each of the first light source 1018 and the second light source 1201.
- the first light beam L21 having a wide angular intensity distribution emitted from the first light source 1018 is directly incident on the light incident surface 1015c of the surface emitting light guide plate 1015.
- the second light beam L22 emitted from the second light source 1201 in the substantially + z-axis direction is incident on the light reflecting surface 1202a of the cylindrical mirror 1202.
- the second light ray L22 emitted from the second light source 1201 has a narrow angular intensity distribution.
- the full angle of the second light ray L22 is 5 °.
- the second light ray L22 has a size in the zx plane.
- the fact that the second light beam L22 has a size means that the second light beam L22 has a light beam diameter of a certain thickness in the x-axis direction of FIG.
- the second light ray L22 is incident on the light reflecting surface 1202a of the cylindrical mirror 1202 having a curvature in the zx plane.
- the second light beam L22 is emitted from the cylindrical mirror 1202 at a different angle depending on the incident position on the light reflection surface 1202a. That is, the second light ray L22 has an angular intensity distribution having a narrow full angle when emitted from the second light source 1201.
- the second light beam L22 is converted into a light beam having an angular intensity distribution having a wide full angle equivalent to that of the first light beam L21 through the cylindrical mirror 1202.
- the first light beam L21 is a light beam emitted from the first light source 1018.
- the second light beam L22 emitted from the cylindrical mirror 1202 is incident on the light incident surface 1015c of the surface emitting light guide plate 1015.
- the first light beam L21 (for example, cyan color) and the second light beam L22 (for example, red color) incident on the light incident surface 1015c of the surface light-emitting light guide plate 1015 are mixed and propagated through the mixed region 1015e, and white light ( Mixed beam) L23.
- the mixed region 1015e is a region provided in the vicinity of the light incident surface 1015c of the surface emitting light guide plate 1015.
- each color light beam (that is, the first light beam L21 and the second light beam L22) propagates in the surface light-emitting light-guiding plate 1015 with an equal angular intensity distribution. Accordingly, the illumination light L24 emitted from the surface light-emitting light guide plate 1015 becomes substantially uniform white planar light having no color unevenness in a plane parallel to the xy plane.
- the control unit 1021 controls the light source driving unit 1023 to adjust the ratio between the intensity of the first light beam L21 and the intensity of the second light beam L22, thereby adjusting the luminance and color of the light emitting surface 1015a.
- the surface light source device 1200 of Embodiment 7 includes the first light source 1018, the second light source 1201, and the cylindrical mirror 1202.
- the first light source 1018 is disposed at a position facing the light incident surface (side surface) 1015 c of the surface light-emitting light guide plate 1015.
- the second light source 1201 is disposed at a position closer to the back surface 1015 b than the light incident surface 1015 c of the surface emitting light guide plate 1015.
- the cylindrical mirror 1202 is a light reflecting member that functions as an optical path changing member that guides the second light beam L22 to the light incident surface 1015c.
- the traveling direction of the second light beam L22 is changed by the cylindrical mirror 1202 to the direction toward the light incident surface 1015c of the surface light-emitting light guide plate 1015.
- the thickness of the surface light-emitting light-guiding plate 1015 can be reduced compared to the conventional configuration in which two types of light sources arranged in the thickness direction of the surface light-emitting light-guiding plate are arranged facing the light incident surface of the surface light-emitting light-guiding plate. it can.
- the surface light source device 1200 of the seventh embodiment uses the angular intensity distribution of the second light beam L22 immediately before entering the light incident surface 1015c of the surface emitting light guide plate 1015 as the first light beam immediately before entering the light incident surface 1015c. It approaches the angular intensity distribution of L21.
- the surface light source device 1200 includes a cylindrical mirror 1202.
- the cylindrical mirror 1202 has a function of changing the traveling direction and angular intensity distribution of the second light ray L22.
- the surface light source device 1200 of Embodiment 7 uses the cylindrical mirror 1202 to increase the angular intensity distribution of the second light ray L22 so as to approach the angular intensity distribution of the first light ray L21.
- the in-plane luminance distribution of the planar illumination light emitted from the light emitting surface 1015a through the surface emitting light guide plate 1015 by the first light beam L21 and the second light beam L22 are emitted through the surface emitting light guide plate 1015 in the same manner.
- a difference from the in-plane luminance distribution of the planar illumination light emitted from the surface 1015a is suppressed.
- the surface light source device 1200 can reduce color unevenness.
- the liquid crystal display device 3002 having the surface light source device 1200 of Embodiment 7 can be reduced in thickness.
- the liquid crystal display device 3002 including the surface light source device 1200 of Embodiment 7 can reduce color unevenness of the surface light source device 1200. Therefore, the liquid crystal display device 3002 can reduce color unevenness on the display surface 1011a of the liquid crystal panel 1011 and improve image quality.
- the angular intensity distribution of the second light beam L22 can be finely controlled by appropriately determining the curvature of the cylindrical mirror 1202. Therefore, it is possible to improve the equivalence between the angular intensity distribution of the first light source 1018 and the angular intensity distribution of the second light source 1201. Thereby, it is possible to provide a high-quality image in which color unevenness is further suppressed.
- by appropriately determining the curvature of the cylindrical mirror 1202 it is possible to increase the ratio of the amount of light incident on the light incident surface 1015c of the surface emitting light guide plate 1015 relative to the amount of emitted light. Thereby, the reduction effect of power consumption can be acquired.
- the liquid crystal display device 3002 of Embodiment 7 includes light sources at two locations, that is, the side surface of the surface light emitting light guide plate 1015 and the back surface of the surface light emitting light guide plate 1015. Accordingly, the liquid crystal display device 3002 can increase the number of light sources while suppressing an increase in thickness (dimension in the z-axis direction).
- the first light source 1018 and the second light source 1201 are arranged separately. Accordingly, the light source driving unit 1023 can easily control the first light source 1018 and the second light source 1201 separately.
- the light source driver 1023 can individually control the outputs of the first light source 1018 and the second light source 1201 based on the image signal. Thereby, power consumption can be reduced.
- the contrast can be improved by reducing stray light.
- the “stray light” is light that travels outside the normal optical path in the optical device, and is harmful to image formation.
- FIG. 26 is a cross-sectional view schematically showing another example of the light reflecting member 1302 of the surface light source device 1300 in the liquid crystal display device of the seventh embodiment.
- FIG. 27 is an enlarged cross-sectional view showing the configuration of the light reflecting member 1302 of the surface light source device 1300 shown in FIG. 26 and 27, the same reference numerals are given to the same or corresponding components as those shown in FIG.
- the surface light source device 1300 shown in FIGS. 26 and 27 includes a second light source 1301 and a cross-sectional light reflection mirror 1302 instead of the second light source 1201 and the cylindrical mirror 1202 shown in FIG. This is different from the surface light source device 1200 shown in FIG.
- the cross-sectional wave shape is a shape in which convex portions and concave portions are alternately continued. That is, the light reflecting member 1302 has a light reflecting surface in which convex portions and concave portions are alternately continued.
- the surface light source device 1300 shown in FIGS. 26 and 27 is the same as the surface light source device 1200 shown in FIG. 24 except for the point that the second light source 1301 and the light reflecting mirror 1302 are different. Note that the second light source 1301 is labeled differently from the second light source 1201, but the light source itself is the same.
- the second light source 1301 has the same structure as the second light source 1201 in FIG.
- the second light beam L32 emitted from the second light source 1301 in the substantially + z-axis direction is incident on the light reflecting surface 1302a of the light reflecting mirror 1302.
- the second light beam L32 emitted from the second light source 1301 has a narrow angular intensity distribution.
- the full width at half maximum is 5 °.
- the second light ray L32 has a size in the zx plane.
- size of the 2nd light ray L32 is having a light beam diameter of a certain thickness in the x-axis direction of FIG.
- the second light ray L32 is incident on the light reflecting surface 1302a of the light reflecting mirror 1302 having a curvature in the zx plane.
- the second light beam L32 is emitted from the light reflecting mirror 1302 at different angles depending on the incident position on the light reflecting surface 1302a. That is, the second light beam L32 having a narrow angular intensity distribution is converted into light having a wide angular intensity distribution equivalent to that of the first light beam L31 via the light reflecting surface 1302a of the light reflecting mirror 1302.
- the second light beam L32 is a light beam emitted from the second light source 1301.
- the first light beam L31 is a light beam emitted from the first light source 1018.
- the second light beam L32 emitted from the light reflecting surface 1302a of the light reflecting mirror 1302 is incident on the light incident surface 1015c of the surface emitting light guide plate 1015.
- the traveling direction of the second light beam L32 is changed to the direction toward the light incident surface 1015c of the surface light-emitting light guide plate 1015 by the light reflecting mirror having a cross-sectional wave shape.
- the thickness of the surface light-emitting light guide plate 1015 can be reduced compared to the conventional configuration in which two types of light sources arranged in the thickness direction of the surface light-emitting light guide plate are arranged to face the light incident surface of the surface light-emitting light guide plate. it can.
- the angular intensity distribution of the second light ray L32 is increased so as to approach the angular intensity distribution of the first light ray L31.
- the in-plane luminance distribution of the planar illumination light emitted from the light emitting surface 1015a through the surface emitting light guide plate 1015 by the first light beam L31 and the second light beam L32 similarly emitted through the surface emitting light guide plate 1015 are emitted.
- a difference from the in-plane luminance distribution of the planar illumination light emitted from the surface 1015a is suppressed. Thereby, the surface light source device 1300 can reduce color unevenness.
- the liquid crystal display device having the surface light source device 1300 of Embodiment 7 can be reduced in thickness.
- the liquid crystal display device 3002 having the surface light source device 1300 can reduce the color unevenness of the surface light source device 1300. As a result, color unevenness on the display surface 1011a of the liquid crystal panel 1011 can be reduced and image quality can be improved.
- FIG. 28 is a cross-sectional view schematically showing a light reflecting member of the surface light source device 1400 in the liquid crystal display device of the seventh embodiment. 28, the same reference numerals are given to the same or corresponding components as those shown in FIG.
- a surface light source device 1400 shown in FIG. 28 includes a second light source 1401 and a light reflecting mirror 1402 having a continuous light reflecting surface having a polygonal cross section instead of the second light source 1201 and the cylindrical mirror 1202 shown in FIG. This is different from the surface light source device 1200 shown in FIG.
- the cross-sectional polygonal shape is a polygonal shape in which the cross-section is not a curved surface like a cylindrical mirror but a plurality of straight lines.
- the surface light source device 2400 shown in FIG. 28 is the same as the surface light source device 1200 shown in FIG. 24 except for the point that the second light source 1401 and the light reflection mirror 1402 are different. Note that the second light source 1401 is different in sign from the second light source 1201, but the light source itself is the same.
- L41 is the first light beam from the first light source 1018, and is the same type of light beam as the first light beam L11.
- L42 is the second light beam from the second light source 1401, and is the same type of light beam as the first light beam L12.
- the light reflection surface 1402a has a shape in which a plurality of line segments that form a part of a polygonal cross section cut along a plane parallel to the zx plane are arranged in an arc shape.
- the zx plane is a surface orthogonal to the longitudinal direction (y-axis direction) of the light incident surface 1015c of the surface light-emitting light-guiding plate 1015.
- the light reflecting mirror 1402 is a first light reflecting member.
- the light reflecting surface 1402a is a first light reflecting surface.
- the cross-sectional shape of the light reflecting surface 1402a cut by a plane parallel to the xy plane is linear.
- the xy plane is a plane parallel to the light emitting surface 1015a.
- the light reflecting surface 1402a has a concave light reflecting surface.
- the concave light reflecting surface means that the light reflecting surface 1402a faces the light incident surface 1015c, and therefore the surface facing the light incident surface 1015c is concave. Also by the example of FIG. 28, the same effect as the case of FIG. 24 can be acquired.
- FIG. 29 is a cross-sectional view schematically showing a light reflecting member of the surface light source device 1500 in the liquid crystal display device of the seventh embodiment. 29, the same reference numerals are given to the same or corresponding components as those shown in FIG.
- a surface light source device 1500 shown in FIG. 29 has a light reflection mirror 1503 having a cylindrical convex light reflection surface 1503a in addition to the second light source 1501 and the cylindrical mirror 1502, and the surface light source device shown in FIG. It is different from 1200.
- the cylindrical mirror 1502 has a cylindrical concave light reflecting surface 1502a.
- the surface light source device 1500 shown in FIG. 29 is the same as the surface light source device 1200 shown in FIG.
- the second light source 1501 is different from the second light source 1201 in terms of reference numerals, but the light source itself is the same.
- the cylindrical mirror 1502 is the same as the cylindrical mirror 1202 except that the cylindrical mirror 1502 is different in sign from the cylindrical mirror 1202 but has a different curved surface shape.
- L51 is the first light beam from the first light source 1018, which is the same type of light beam as the first light beam L11.
- L52 is the second light beam from the second light source 1501, and is the same type of light beam as the first light beam L12.
- the cylindrical mirror 1502 has the same shape as the cylindrical mirror in FIG.
- the light reflecting surface 1503a of the light reflecting mirror 1503 has an arcuate cross section cut by a plane parallel to the zx plane.
- the zx plane is a surface orthogonal to the longitudinal direction (y-axis direction) of the light incident surface 1015c of the surface light-emitting light-guiding plate 1015.
- the light reflection surface 1503a has a linear cross-sectional shape cut by a plane parallel to the xy plane.
- the xy plane is a plane parallel to the light emitting surface 1015a.
- the light reflecting surface 1503a has a convex light reflecting surface 1503a.
- the light reflecting surface 1503a faces the light incident surface 1015c. Also in the example of FIG. 29, the same effect as in the case of FIG. 24 can be obtained.
- the second light beam L52 is reflected by the light reflecting surface 1503a, and then reflected by the light reflecting surface 1502a and emitted toward the surface emitting light guide plate 1015.
- the second light ray L52 having a narrow angular intensity distribution becomes light having a wider and messy angular intensity distribution due to reflection on a cylindrical concave light reflecting surface or a cylindrical convex light reflecting surface such as a cylindrical mirror.
- Both the cylindrical mirror 1502 and the light reflecting mirror 1503 are designed in consideration of the angular intensity distribution of the second light beam L52 emitted from the second light source 1501, the light diameter in the zx plane, the thickness of the surface emitting light guide plate 1015, and the like.
- the With such a mirror design the angular intensity distribution of the second light source 1501 can be controlled more finely. Therefore, according to the example of FIG. 29, it is possible to improve the equivalence of the angular intensity distribution of the first light ray L51 and the angular intensity distribution of the second light ray L52.
- the first light beam L51 is a light beam emitted from the first light source 1018.
- the second light beam L52 is a light beam emitted from the second light source 1501.
- both the cylindrical mirror 1502 and the light reflecting mirror 1503 can employ a highly workable resin or metal such as acrylic resin (for example, PMMA) or polycarbonate for the base material.
- the light reflecting surface can be formed of, for example, an aluminum, gold, or silver layer.
- FIG. 30 is a cross-sectional view schematically showing a configuration of a liquid crystal display device 3006 (including a surface light source device 1600) according to an eighth embodiment.
- the surface light source device 1600 includes a surface emitting light guide plate 1015, a light reflection sheet 1017, a light guide member 1610, a cylindrical mirror 1602, a first light source 1018, and a second light source 1601.
- the surface light source device 1700 includes a surface light-emitting light guide plate 1015, a light reflection sheet 1017, a light guide member 1710, a cylindrical mirror 1702, a first light source 1018, and a second light source 1601.
- the surface light source device 1800 includes a surface light-emitting light guide plate 1015, a light reflection sheet 1017, a light guide member 1810, a cylindrical mirror 1802, a light reflection mirror 1803, a first light source 1018, and a second light source 1801.
- FIG. 31 is a diagram showing a configuration in the vicinity of the light incident surface 1015c of the surface light-emitting light-guiding plate 1015 of the surface light source device (backlight unit) 1600 shown in FIG. 30 and 31, the same reference numerals are given to the same or corresponding components as those shown in FIG. 18.
- the liquid crystal display device 3006 and the surface light source device 1600 in the eighth embodiment are the second light sources 1101, 1111 (or configurations 1201, 1301, 1401, 1501) and diffuse reflection members 1102, 1112 (in the sixth embodiment (or 7)).
- the liquid crystal display device of Embodiment 6 (or 7) is provided with a second light source 1601, a light source light guide member 1610, and a cylindrical mirror 1602. 3001, 3011 (or 3002) and the surface light source devices 1100, 1112 (or 1200, 1300, 1400, 1500).
- the diffuse reflection members 1102 and 1112 have a function as an optical path changing member.
- the cylindrical mirror 1602 has a function as a light reflecting member.
- the liquid crystal display device 3006 and the surface light source device 1600 of the eighth embodiment are the same as the liquid crystal of the sixth embodiment (or 7). It is the same as the display device 3001 (or 3002) and the surface light source device 1100 (or 1200, 1300, 1400, 1500).
- symbol of the 2nd light source 1601 differs from the 2nd light sources 1101 and 1111, it is the same as a light source.
- the liquid crystal display device 3006 of Embodiment 8 includes a liquid crystal panel 1011, a first optical sheet 1012, a second optical sheet 1013, a surface emitting light guide plate 1015, A micro optical element 1016, a light reflection sheet 1017, a first light source 1018, a second light source 1601, a light source light guide member 1610, and a cylindrical mirror 1602 are provided. These configurations 1011, 1012, 1013, 1015, 1016, 1017, and 1610 are arranged in order in the thickness direction ( ⁇ z-axis direction) of the liquid crystal display device 3006.
- the first light source 1018 is disposed within the range of the length in the z-axis direction of the light incident surface (side surface) 1015c of the surface light-emitting light-guiding plate 1015.
- the length of the light incident surface 1015c in the z-axis direction indicates the thickness of the surface emitting light guide plate 1015.
- the first light beam L61 emitted from the first light source 1018 travels (approximately in the + x axis direction) toward the light incident surface 1015c of the surface emitting light guide plate 1015, and enters the light incident surface 1015c of the surface emitting light guide plate 1015.
- the first light source 1018 is, for example, a light source device in which a plurality of LED elements are linearly arranged at equal intervals.
- the configuration of the first light source 1018 is not limited to such a configuration, and may be a light source device having another configuration.
- the second light source 1601 is a light source device in which a plurality of laser light emitting elements are arranged on a straight line at equal intervals, similarly to the second light source 1101 in the sixth embodiment.
- the configuration of the second light source 1601 is not limited to such a configuration, and may be a light source device having another configuration.
- the second light source 1601 is disposed on the back surface side ( ⁇ z-axis direction) of the light reflecting sheet 1017.
- the second light source 1601 is disposed so as to face the light incident end 1610a of the light guide member 1610 for the light source.
- the light guide member 1610 for the light source includes a light guide unit 1611 and a light turnup unit 1612.
- the light guide part 1611 is a rectangular parallelepiped plate-like part arranged in parallel to the xy plane.
- the light folding portion 1612 is a triangular prism-shaped portion arranged in parallel to the xy plane.
- the light source light guide member 1610 is, for example, a plate-like member having a thickness of 1 mm.
- the light guide member 1610 for light source is made of a transparent material made of acrylic resin such as PMMA, for example.
- the shape, size, and arrangement of the light guide member 1610 for the light source are not limited to the illustrated example.
- the second light ray L62 has an angular intensity distribution in which the full width at half maximum is 5 °.
- the incident angle of the second light beam L62 with respect to the inclined end surface 1610b is adjusted so that all of the second light rays L62 are totally reflected on the inclined end surface 1610b of the light guide member 1610 for the light source.
- optical loss can be suppressed.
- ⁇ t sin ⁇ 1 (1.00 / 1.49) ⁇ 42.16 ° It becomes.
- the incident angle of the second light ray L62 with respect to the inclined end surface 1610b is ( It is desirable that the angle be 44.7 ° or more so as to satisfy ⁇ t + 2.5) °.
- the light source light guide member 1610 has a light incident end 1610a, an inclined end surface 1610b, and a light emitting surface 1610c.
- the inclined end surface 1610b faces the light reflecting surface 1602a of the cylindrical mirror 1602.
- the inclined end surface 1610b is inclined at an angle of approximately 45 ° with respect to the xy plane.
- the inclined end surface 1610b of the light guide member 1610 for light source changes the traveling direction of the second light ray L62 from the ⁇ x-axis direction to the approximately + z-axis direction.
- the second light ray L62 is reflected by the difference in refractive index at the interface between the light guide member 1610 for light source and the air layer on the inclined end surface 1610b, and the traveling direction is changed to the substantially + z-axis direction.
- the second light beam L62 emitted from the second light source 1601 enters the light guide member 1610 for the light source from the light incident end 1610a of the light guide member 1610 for the light source. Thereafter, the second light ray L62 repeats total reflection at the interface between the light source light guide member 1610 and the air layer, and travels (propagates) in the light source light guide member 1610 in the ⁇ x-axis direction to reach the inclined end surface 1610b. . Thereafter, the second light ray L62 is reflected by the inclined end face 1610b and changes its traveling direction in the substantially + z-axis direction. The second light beam L62 whose traveling direction is changed is emitted from the light emitting surface 1610c. Thereafter, the second light beam L62 is reflected by the cylindrical mirror 1602 and is incident on the light incident surface 1015c of the surface-emitting light guide plate 1015.
- the light reflecting surface 1602a of the cylindrical mirror 1602 has the same shape and function as the light reflecting surface 1202a of the cylindrical mirror 1202 shown in FIG.
- the second light ray L62 emitted from the light emitting surface 1610c travels toward the light reflecting surface 1602a of the cylindrical mirror 1602, is reflected by the light reflecting surface 1602a, and directs the traveling direction toward the light incident surface 1015c of the surface emitting light guide plate 1015. (Look roughly in the + x axis direction).
- the full width at half maximum of the angular intensity distribution of the second light ray L62 reflected by the light reflecting surface 1602a of the cylindrical mirror 1602 increases and approaches the full width at half maximum of the angular intensity distribution of the first light ray L61.
- the first light beam L61 and the second light beam L62 incident on the light incident surface 1015c of the surface light-emitting light guide plate 1015 are mixed in the mixed region 1015e to become a mixed light beam L63.
- the light reflecting sheet 1017 is disposed so as to face the back surface 1015b of the surface emitting light guide plate 1015.
- the mixed light beam L63 the light emitted from the back surface 1015b of the surface light-emitting light guide plate 1015 is reflected by the light reflecting sheet 1017 and turned back, and travels toward the back surface 1015b of the surface light-emitting light guide plate 1015.
- the light passes through the light emitting surface 1015a toward the back surface 1011b of the liquid crystal panel 1011 and is emitted as illumination light L64.
- the light beam that has entered the micro optical element 1016 is also emitted as illumination light L64.
- the inclined end surface 1610b of the light guide member 1610 for the light source is inclined at an angle of approximately 45 ° with respect to the xy plane, but the present invention is not limited to this.
- the inclination angle of the inclined end face 1610b with respect to the xy plane may be changed.
- the optimum optical path of the second light beam L62 is determined by the incident angle of the second light beam L62 with respect to the inclined end surface 1610b, and the positional relationship and arrangement angle relationship between the light output surface 1610c, the cylindrical mirror 1602, and the surface light-emitting light guide plate 1015.
- the arrangement and the angle of the cylindrical mirror 1602 may be adjusted instead of the adjustment of the inclination angle of the inclined end surface 1610b.
- the thinning of the light guide member 1610 for the light source in the eighth embodiment leads to the miniaturization of the cylindrical mirror 1602. Furthermore, it leads to thickness reduction of the surface emitting light-guide plate 1015. FIG. Therefore, it is desirable to use the light source light guide member 1610 having a small thickness. However, if the thickness is reduced, the rigidity of the light guide member 1610 for the light source decreases. For this reason, it is desirable to make it thin as long as the rigidity of the light guide member 1610 for the light source does not decrease too much.
- the second light beam L62 emitted from the light guide member 1610 for the light source toward the cylindrical mirror 1602 has a size equivalent to the thickness of the light guide member 1610 for the light source in the zx plane.
- the second light beam L ⁇ b> 62 travels through the light source light guide member 1610 and is emitted from the light emitting end 1610 c of the light source light guide member 1610.
- the light emitted from the light emitting end 1610c emits a light beam having the same angular intensity distribution as that immediately after being emitted from the second light source 1601.
- the light emitted from the light emitting end 1610c is emitted from an arbitrary region of the light emitting end 1610c according to the reflection position of the inclined end surface 1610b. That is, a light beam having the same angular intensity distribution as that immediately after being emitted from the second light source 1601 is emitted from an arbitrary region of the light emitting end 1610c.
- the tangential direction of the arc-shaped cylindrical mirror 1602 changes in the zx plane position according to the position of the emitted light exit end 1610c of the second light ray L62.
- the angular intensity distribution of the second light source 1601 can be further expanded.
- the light guide member 1610 for the light source is not limited to a transparent member.
- the function of the light guide member 1610 for the light source is to guide the second light beam L62 to the cylindrical mirror 1602.
- the first light beam L61 is a light beam emitted from the first light source 1018.
- the second light beam L62 is a light beam emitted from the second light source 1601.
- the light guide member 1610 for light sources may be set as another structure.
- the inclined end surface 1610b may be a light reflecting mirror that faces the second light source 1601 side.
- the light guide member 1610 for the light source may be configured by a plane mirror instead of the light guide unit 1611 and the light folding unit 1612.
- the configuration includes the cylindrical mirror 1602 as the optical path changing member immediately after the light guide member 1610 for the light source.
- the present invention is not limited to this. You may employ
- the liquid crystal display device 3006 of Embodiment 8 has a configuration in which light emitted from two light sources arranged at different positions enters from a short side surface of the surface-emitting light guide plate 1015.
- the arrangement of the first light source and the second light source, the position of the light guide member 1610 for the light source, the arrangement of the micro optical elements 1016, etc. the long side surface of the surface emitting light guide plate 1015 can also be used as the incident surface. It is.
- ⁇ 8-2 Operation of Embodiment 8
- the surface light source device 1600 When the surface light source device 1600 is turned on, light is emitted from each of the first light source 1018 and the second light source 1601.
- the first light beam L61 (for example, cyan) emitted from the first light source 1018 travels in a direction (substantially + x-axis direction) toward the light incident surface 1015c of the surface light-emitting light guide plate 1015.
- the second light beam L62 emitted from the second light source 1601 enters the light guide member 1610 for the light source from the light incident end 1610a.
- the second light ray L62 is, for example, a red light ray.
- the second light ray L62 repeats total reflection at the interface between the light source light guide member 1610 and the air layer, and propagates in the ⁇ x-axis direction while being confined in the light source light guide member 1610. At this time, the angular intensity distribution of the second light ray L62 is stored.
- the angular intensity distribution of the second light ray L62 emitted from the light emitting surface 1610c is equal to the angular intensity distribution of the second light ray L62 emitted from the second light source 1601, and the full width at half maximum of each angular intensity distribution is Same angle.
- the full width at half maximum of the angular intensity distribution is 5 °.
- the light emitted from the light emitting surface 1610c of the light guide member 1610 for the light source is directed to the light reflecting surface 1602a of the cylindrical mirror 1602, and the traveling direction is directed to the light incident surface 1015c of the surface light-emitting light guide plate 1015 by the cylindrical mirror 1602 (substantially). + X-axis direction) and the full width at half maximum of the angular intensity distribution increases.
- the first light beam L61 and the second light beam L62 incident on the light incident surface 1015c of the surface light emitting light guide plate 1015 are mixed by propagating through the mixed region 1015e provided in the vicinity of the light incident surface 1015c of the surface light emitting light guide plate 1015. It becomes white light (mixed light beam L63). Thereafter, the mixed light beam L63 is emitted toward the liquid crystal panel 1011 as the planar illumination light L64 from the light emitting surface 1015a of the surface light emitting light guide plate 1015 through reflection by the micro optical element 1016 or reflection by the light reflecting sheet 1017. .
- each color light beam (that is, the first light beam L61 and the second light beam L62) propagates in the surface light-emitting light guide plate 1015 with an equal angular intensity distribution. Therefore, the illumination light L64 emitted from the surface light-emitting light guide plate 1015 becomes substantially uniform white planar light having no color unevenness in a plane parallel to the xy plane.
- the control unit 1021 controls the light source driving unit 1023 to adjust the ratio between the intensity of the first light beam L61 and the intensity of the second light beam L62, thereby adjusting the luminance and color of the light emitting surface 1015a.
- the surface light source device 1600 of the eighth embodiment includes the first light source 1018, the second light source 1601, the light source light guide member 1610, and the cylindrical mirror. 1602.
- the first light source 1018 is disposed at a position facing the light incident surface (side surface) 1015 c of the surface light-emitting light guide plate 1015.
- the second light source 1601 is disposed at a position closer to the back surface 1015 b than the light incident surface 1015 c of the surface emitting light guide plate 1015.
- the light guide member 1610 for the light source has a function as an optical path changing member that guides the second light beam L62 to the light incident surface 1015c.
- the traveling direction of the second light beam L62 is changed to the direction toward the light incident surface 1015c of the surface emitting light guide plate 1015 by the optical path changing member.
- the thickness of the surface light-emitting light-guiding plate 1015 can be reduced compared to the conventional configuration in which two types of light sources arranged in the thickness direction of the surface light-emitting light-guiding plate are arranged facing the light incident surface of the surface light-emitting light-guiding plate. it can.
- the surface light source device 1600 of the eighth embodiment includes a cylindrical mirror 1602.
- the cylindrical mirror 1602 brings the angular intensity distribution of the second light beam L62 immediately before entering the light incident surface 1015c of the surface light-emitting light guide plate 1015 closer to the angular intensity distribution of the first light beam L61 immediately before entering the light incident surface 1015c. Further, the traveling direction and angular intensity distribution of the second light ray L62 are changed. As described above, according to the surface light source device 1600 of the eighth embodiment, the angular intensity distribution of the second light ray L62 is increased using the cylindrical mirror 1602 so as to approach the angular intensity distribution of the first light ray L61.
- the in-plane luminance distribution of the planar illumination light emitted from the light emitting surface 1015a through the surface light emitting light guide plate 1015 and the second light ray L62 are also emitted through the surface light emitting light guide plate 1015.
- a difference from the in-plane luminance distribution of the planar illumination light emitted from the surface 1015a is suppressed. Thereby, the color unevenness of the surface light source device 1600 is reduced.
- the liquid crystal display device 3006 having the surface light source device 1600 of Embodiment 8 can be reduced in thickness.
- the liquid crystal display device 3006 having the surface light source device 1600 of Embodiment 8 can reduce the color unevenness of the surface light source device 1600, the color unevenness on the display surface 1011a of the liquid crystal panel 1011 can be reduced and the image quality can be reduced. Can be improved.
- the first light source 1018 and the second light source 1601 can be arranged at positions separated from each other.
- LED elements and laser light emitting elements employed in the first light source 1018 and the second light source 1601 have an electro-optical conversion efficiency of 10 to 50%.
- the energy that is not converted into light becomes heat.
- these heat sources are concentrated in a narrow area. For this reason, the heat dissipation capability decreases, and the ambient temperature of the first light source 1018 and the second light source 1601 increases.
- the luminous efficiency of these light sources decreases as the ambient temperature increases.
- the first light source 1018 and the second light source 1601 are arranged apart from each other. For this reason, a heat source disperse
- the laser light emitting element has a large reduction in light emission efficiency and a large amount of spectrum shift with respect to temperature change. By disposing the laser light emitting element in one place isolated from other heat sources, the cooling mechanism of the laser light emitting element can be arranged in one place, so that the cooling mechanism can be efficiently provided.
- the first light source 1018 and the second light source 1601 are separately arranged. Therefore, the light source driving unit 1023 can easily control the two first light sources 1018 and the second light source 1601 separately. This is because the light source driving unit 1023 can individually control the outputs of the first light source 1018 and the second light source 1601 based on the image signal. This individual control of different light sources can reduce power consumption. Further, the individual control of the different light sources can reduce the stray light and improve the contrast.
- the liquid crystal display device 3006 of the eighth embodiment can increase the number of light sources while suppressing an increase in the thickness of the liquid crystal display device 3006 even when a plurality of different types of light sources are provided. ing. Therefore, a liquid crystal display device 3006 that can achieve both high brightness and thinness can be realized.
- the surface-emitting light guide plate that uses the light from a plurality of types of light sources as a surface light source is shared, an increase in weight and cost can be suppressed.
- the angular intensity distribution of a light source having a narrower angular intensity distribution can be matched with the angular intensity distribution of the other light source. For this reason, the difference of the in-plane luminance distribution of the surface light source produced
- these light sources have different spectra, color unevenness can be suppressed.
- a plurality of light sources having different angular intensity distributions are employed.
- a laser light emitting device that is very excellent in monochromaticity has high directivity. Therefore, this embodiment is effective as a configuration for extending the color reproduction range.
- FIG. 32 is a cross sectional view schematically showing a configuration of another example of liquid crystal display device 3007 (including surface light source device 1700) according to the eighth embodiment.
- the same reference numerals are given to the same or corresponding components as those shown in FIG.
- the liquid crystal display device 3007 and the surface light source device 1700 in FIG. 32 are different from the liquid crystal display device 3006 and the surface light source device 1600 in FIG.
- the difference in arrangement is that the light guide member 1710 for light source is arranged to be inclined with respect to the surface emitting light guide plate 1015. That is, the light source light guide member 1710 is disposed to be inclined with respect to the xy plane.
- the difference in shape is that the inclination angle of the inclined end face 1710b is different.
- the light source light guide member 1710 functions as an optical path changing member.
- the liquid crystal display device 3007 and the surface light source device 1700 are different from the liquid crystal display device 3006 and the surface light source device 1600 in FIG.
- the shape of the light reflecting surface 1702a of the cylindrical mirror 1702 in FIG. 32 is the same as the shape of the light reflecting surface 1602a of the cylindrical mirror 1602 in FIG.
- the liquid crystal display device 3007 and the surface light source device 1700 shown in FIG. 32 are the same as the liquid crystal display device 3006 and the surface light source device 1600 shown in FIG.
- the other point is a point other than a point where the shape and arrangement of the light guide member 1710 for the light source are different, and is a point other than a point where the arrangement of the second light source is different.
- the light guide member 1710 for the light source has a light incident end 1710a, an inclined end surface 1710b, and a light emitting surface 1710c.
- the inclined end surface 1710b faces the light reflecting surface 1702a of the cylindrical mirror 1702.
- the inclined end surface 1710b is inclined with respect to the xy plane.
- the inclined end surface 1710b of the light guide member 1710 for the light source changes the traveling direction of the second light ray L72 from the substantially ⁇ x axis direction to the approximately + z axis direction.
- the second light ray L72 is reflected by the difference in refractive index at the interface between the light guide member 1710 for the light source and the air layer on the inclined end surface 1710b, and the traveling direction is changed to the substantially + z-axis direction.
- the light guide member 1710 for the light source is inclined with respect to the xy plane so that the light incident end 1710a is further away from the light reflecting sheet 1017.
- the second light source 1701 is a laser light emitting element similar to the second light source 1601 in FIG.
- the second light source 1701 is disposed on the back surface side ( ⁇ z-axis direction) of the light reflecting sheet 1017.
- the second light source 1701 is disposed to face the light incident end 1710a of the light guide member 1710 for the light source.
- the light source light guide member 1710 is made of the same material as the light source light guide member 1610 of FIG.
- the light guide member 1710 for the light source is composed of a rectangular parallelepiped plate-like portion 1711 arranged to be inclined with respect to the xy plane, and a triangular prism-like light return portion 1712.
- the first light beam L71 emitted from the first light source 1018 travels in a direction (substantially + x-axis direction) toward the light incident surface 1015c of the surface emitting light guide plate 1015.
- the second light beam L72 emitted from the second light source 1701 is incident on the light incident end 1710a of the light source light guide member 1710, and repeats total reflection at the interface between the light source light guide member 1710 and the air layer to guide the light source. Propagate while confined within member 1710. At this time, the angular intensity distribution of the second light ray L72 is stored.
- the angular intensity distribution of the second light ray L72 emitted from the light emitting surface 1710c is equal to the angular intensity distribution of the second light ray L72 when emitted from the second light source 1701, and the full width at half maximum of each angular intensity distribution is The same angle.
- the full width at half maximum of the angular intensity distribution is 5 °.
- the second light beam L72 emitted from the light emission surface 1710c of the light guide member 1710 for the light source travels toward the light reflection surface 1702a of the cylindrical mirror 1702.
- the traveling direction of the second light beam L72 is changed by the cylindrical mirror 1702 to a direction (substantially + x-axis direction) toward the light incident surface 1015c of the surface light-emitting light-guiding plate 1015.
- the full width at half maximum of the angular intensity distribution of the second light ray L72 becomes large.
- the first light beam L71 and the second light beam L72 incident on the light incident surface 1015c of the surface light-emitting light guide plate 1015 are mixed and propagated through the mixed region 1015e to become white light (mixed light beam L73).
- the mixed region 1015e is provided in the vicinity of the light incident surface 1015c of the surface light-emitting light guide plate 1015.
- the first light beam L71 and the second light beam L72 are reflected from the light emitting surface 1015a of the surface light emitting light guide plate 1015 through reflection on the micro optical element 1016 or reflection by the light reflecting sheet 1017, and the like.
- Light L74 is emitted toward the liquid crystal panel 1011.
- the traveling direction of the second light beam L72 is changed to the direction toward the light incident surface 1015c of the surface light-emitting light-guiding plate 1015 by the optical path changing member.
- the thickness of the surface light-emitting light guide plate 1015 can be reduced compared to the conventional configuration in which two types of light sources arranged in the thickness direction of the surface light-emitting light guide plate are arranged facing the light incident surface of the surface light-emitting light guide plate. it can.
- the surface light source device 1700 shown in FIG. 32 uses the cylindrical mirror 1702 to increase the angular intensity distribution of the second light beam L72 so as to approach the angular intensity distribution of the first light beam L71.
- the in-plane luminance distribution of the planar illumination light emitted from the light emitting surface 1015a through the surface emitting light guide plate 1015 by the first light ray L71 and the second light ray L72 similarly emitted through the surface emitting light guide plate 1015 are emitted.
- a difference from the in-plane luminance distribution of the planar illumination light emitted from the surface 1015a is suppressed. Thereby, the color unevenness of the surface light source device 1700 is reduced.
- the liquid crystal display device 3007 having the surface light source device 1700 can be reduced in thickness.
- the liquid crystal display device 3007 including the surface light source device 1700 can reduce color unevenness of the surface light source device 1700, color unevenness on the display surface 1011a of the liquid crystal panel 1011 can be reduced and image quality can be improved. .
- the light guide member 1710 for the light source is not limited to a transparent member.
- the function of the light guide member 1710 for the light source is to guide the second light beam L72 to the cylindrical mirror 1702. If it is the structure with this function, the light guide member 1710 for light sources may be set as another structure.
- the light guide member 1710 for the light source may be only the light guide unit 1711, and the light emitted from the light guide unit 1710 may be directly incident on the cylindrical mirror 1702.
- FIG. 34 is a cross sectional view schematically showing a configuration of another example of the liquid crystal display device 3008 (including the surface light source device 1800) of the eighth embodiment. . 34, the same reference numerals are given to the same or corresponding components as those shown in FIG.
- the liquid crystal display device 3008 and the surface light source device 1800 in FIG. 34 are different from the liquid crystal display device 3006 and the surface light source device 1600 in FIG. 30 in the following points.
- the first difference is the shape of the light guide member 1810 for the light source as the optical path changing member.
- the second difference is that a light reflecting mirror 1803 (having a convex second light reflecting surface 1803a) is provided.
- a third difference is that a cylindrical mirror 1802 (having a concave first light reflecting surface 1802a) is provided.
- the second light source 1801 is the same light source as the liquid crystal display device 3006 and the surface light source device 1600 of FIG.
- the shape of the light reflecting surface 1802a of the cylindrical mirror 1802 is the same as the shape of the light reflecting surface 1602a of the cylindrical mirror 1602 in FIG.
- the liquid crystal display device 3008 and the surface light source device 1800 in FIG. 34 are the same as the liquid crystal display device 3006 and the surface light source device 1600 in FIG.
- the second light source 1801 is a light source device including a laser light emitting element similar to the second light source 1601 in FIG.
- the light source device is, for example, one in which a plurality of laser light emitting elements are arranged at equal intervals in the y-axis direction.
- the second light source 1801 is a light source device in which a plurality of laser light emitting elements are arranged.
- the second light source 1801 is disposed on the back surface side ( ⁇ z-axis direction) of the light reflecting sheet 1017.
- the second light source 1801 is disposed so as to face the light incident end 1810a of the light guide member 1810 for the light source.
- the light source light guide member 1810 is made of the same material as the light source light guide member 1610 of FIG.
- the light source light guide member 1810 is configured by a rectangular parallelepiped plate-like portion arranged in parallel to the xy plane. As shown in FIG. 34, the light source light guide member 1810 has a light incident end 1810a and a light emitting end 1810b.
- the light reflecting mirror 1803 is a reflecting member that directs the traveling direction of the second light beam L82 emitted from the light guide member 1810 for the light source toward the cylindrical mirror 1802.
- the second light beam L82 is emitted from the second light source 1801, passes through the light source light guide member 1810, and then is emitted toward the light reflecting mirror 1803.
- the light reflecting surface 1803a of the light reflecting mirror 1803 has an arc shape whose cross section cut along the zx plane is convex in the direction of the light incident surface 1015c.
- the zx plane is a surface orthogonal to the longitudinal direction (y-axis direction) of the light incident surface 1015c.
- the light reflecting surface 1803a of the light reflecting mirror 1803 is a linear shape whose cross-sectional shape cut along the xy plane extends in the y-axis direction.
- the xy plane is a plane parallel to the light emitting surface 1015a.
- the y-axis direction is the longitudinal direction of the light incident surface 1015c.
- the light reflecting surface 1803a is a convex cylindrical light reflecting surface facing the light incident surface 1015c.
- the shape of the light reflection mirror 1803 may be another member as long as it is an optical member that directs the traveling direction of the second light beam L82 toward the cylindrical mirror 1802.
- a light beam is emitted from each of the first light source 1018 and the second light source 1801.
- the first light beam L81 emitted from the first light source 1018 travels in a direction (substantially + x-axis direction) toward the light incident surface 1015c of the surface emitting light guide plate 1015.
- the second light beam L82 emitted from the second light source 1801 is incident on the light incident end 1810a of the light source light guide member 1810 and repeats total reflection at the interface between the light source light guide member 1710 and the air layer to guide the light source. Propagate while confined within member 1710. At this time, the angular intensity distribution of the second light ray L72 is stored.
- the angular intensity distribution of the second light ray L82 emitted from the light emitting end 1810b is equal to the angular intensity distribution of the second light ray L82 emitted from the second light source 1801.
- the full width at half maximum of each angular intensity distribution is the same angle.
- the full width at half maximum of each angular intensity distribution is 5 °.
- the second light beam L82 emitted from the light emitting end 1810b of the light source guide member 1810 is reflected by the light reflecting surface 1803a of the light reflecting mirror 1803. At this time, the full width at half maximum of the angular intensity distribution of the second light ray L82 increases.
- the second light ray L82 is directed to the light reflecting surface 1802a of the cylindrical mirror 1802, and the traveling direction is changed by the cylindrical mirror 1802 to a direction (substantially + x-axis direction) toward the light incident surface 1015c of the surface light-emitting light guide plate 1015.
- the second light ray L82 is reflected by the light reflecting surface 1802a, the full width at half maximum of the angular intensity distribution is increased.
- the first light beam L81 and the second light beam L82 incident on the light incident surface 1015c of the surface light emitting light guide plate 1015 are mixed by propagating through the mixed region 1015e provided in the vicinity of the light incident surface 1015c of the surface light emitting light guide plate 1015. It becomes white light (mixed ray L83). After that, the mixed light beam L83 is emitted toward the liquid crystal panel 1011 as planar illumination light L84 from the light emitting surface 1015a of the surface light emitting light guide plate 1015 through reflection by the micro optical element 1016 and reflection by the light reflecting sheet 1017. .
- the traveling direction of the second light beam L82 is changed to the direction toward the light incident surface 1015c of the surface light-emitting light-guiding plate 1015 by the optical path changing member.
- the thickness of the surface light-emitting light guide plate 1015 can be reduced compared to the conventional configuration in which two types of light sources arranged in the thickness direction of the surface light-emitting light guide plate are arranged facing the light incident surface of the surface light-emitting light guide plate. it can.
- the angular intensity distribution of the second light ray L82 is increased using the light reflecting mirror 1803 and the cylindrical mirror 1802 so as to approach the angular intensity distribution of the first light ray L81. Yes.
- the in-plane luminance distribution of the planar illumination light formed by the first light beam L81 being emitted from the light emitting surface 1015a via the surface light emitting light guide plate 1015, and the second light beam L82 are also transmitted via the surface light emitting light guide plate 1015.
- a difference from the in-plane luminance distribution of the planar illumination light emitted from the light emitting surface 1015a is suppressed. For this reason, the color unevenness of the surface light source device 1800 is reduced.
- the liquid crystal display device 3008 having the surface light source device 1800 can be thinned. Further, the liquid crystal display device 3008 including the surface light source device 1800 can reduce the color unevenness of the surface light source device 1800, so that the color unevenness on the display surface 1011a of the liquid crystal panel 1011 can be reduced and the image quality can be improved. .
- FIG. 35 is a cross-sectional view schematically showing a configuration of a liquid crystal display device 3009 (including a surface light source device 1900) according to the ninth embodiment.
- the surface light source device 1900 includes a surface light-emitting light guide plate 1015, a light reflection sheet 1017, a diffuse reflection member 1902, a first light source 1018, and a second light source 1019.
- the surface light source device 2000 includes a surface emitting light guide plate 1015, a light reflecting sheet 1017, a light reflecting member 2002, a first light source 1018, and a second light source 2001.
- the surface light source device 2100 includes a surface emitting light guide plate 1015, a light reflecting sheet 1017, a light reflecting member 2102, a first light source 1018, and a second light source 2101.
- the surface light source device 2200 includes a surface emitting light guide plate 1015, a light reflecting sheet 1017, a light reflecting member 2202, a first light source 1018, and a second light source 2201.
- the surface light source device 2300 includes a surface emitting light guide plate 1015, a light guide member 2311, a cylindrical mirror 2302, a first light source 1018, and a second light source 2301.
- the surface light source device 2400 includes a surface emitting light guide plate 1015, a light guide member 2311, a cylindrical mirror 2402, a first light source 1018, and a second light source 2401.
- FIG. 35 the same or corresponding components as those shown in FIG. 18 of the sixth embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.
- the arrangement position of the first light source 1018, the arrangement position of the second light source 1901, and the arrangement position of the diffuse reflection member 1902 are the same as those of the liquid crystal display device 3001 of the sixth embodiment.
- the surface light source device 1100 is the same as those of the liquid crystal display device 3001 of the sixth embodiment.
- each component is arranged in the order of the second light source 1101, the diffuse reflection member 1102, and the first light source 1018 in the + z-axis direction.
- the respective components are arranged in the order of the second light source 1901, the first light source 1018, and the diffuse reflection member 1902 in the + z-axis direction.
- the liquid crystal display device 3009 and the surface light source device 1900 of the ninth embodiment are the same as the liquid crystal display device 3001 and the surface light source device 1100 of the sixth embodiment.
- the first light source 1018 emits a first light beam L91 (for example, blue-green).
- Second light source 1901 has the same configuration as second light source 1101 in the sixth embodiment, and emits second light beam L92 (for example, red).
- the first light ray L91 travels in the substantially + x-axis direction from the first light source 1018 toward the light incident surface 1015c.
- the second light ray L92 travels in the approximately + z-axis direction from the second light source 1901, and then is reflected by the diffuse reflection member 1902 and changes the traveling direction in the approximately + x-axis direction.
- the diffuse reflection member 1902 has the same configuration as the diffuse reflection member 1102 in the sixth embodiment.
- Both the first light beam L91 and the second light beam L92 are incident on the light incident surface 1015c of the surface emitting light guide plate 1015.
- the first light beam L91 and the second light beam L92 are mixed in the mixed region 1015e in the vicinity of the light incident surface 1015c in the surface emitting light guide plate 1015, and become a white mixed light beam L93.
- the diffuse reflection member 1902 is arranged in the + z-axis direction from the first light source 1018.
- the second light source 1901 is disposed to face the light reflecting surface 1902a of the diffuse reflecting member 1902.
- the diffused light reflecting surface 1902a of the diffuse reflecting member 1902 is disposed so as to face the light incident surface 1015c of the surface emitting light guide plate 1015.
- ⁇ 9-2 Operation of Embodiment 9
- the surface light source device 1900 When the surface light source device 1900 is turned on, light is emitted from each of the first light source 1018 and the second light source 1901.
- the first light ray L91 having a wide angular intensity distribution emitted from the first light source 1018 is directly incident on the light incident surface 1015c of the surface emitting light guide plate 1015.
- the second light beam L92 emitted from the second light source 1901 in the substantially + z-axis direction is incident on the light reflection surface 1902a of the diffuse reflection member 1902.
- the second light ray L92 emitted from the second light source 1901 has a narrow angular intensity distribution with a full width at half maximum of 5 °.
- the second light ray L92 has a size in the zx plane. That is, the light beam diameter has a certain thickness in the x-axis direction of FIG.
- the second light ray L92 is applied to the diffused light reflecting surface 1902a of the light diffusing member 1902 to increase the full width at half maximum of the angular intensity distribution of the second light ray L92.
- the second light ray L92 changes the traveling direction to a direction toward the light incident surface 1015c of the surface emitting light guide plate 1015 (substantially + x-axis direction).
- the first light beam L91 (for example, cyan color) and the second light beam L92 (for example, red color) incident on the light incident surface 1015c of the surface light-emitting light guide plate 1015 are mixed and propagated through the mixed region 1015e to generate white light ( Mixed light) L93.
- the mixed region 1015e is provided in the vicinity of the light incident surface 1015c of the surface emitting light guide plate 1015.
- the mixed light beam L93 is emitted toward the liquid crystal panel 1011 as planar illumination light L94 from the light emitting surface 1015a of the surface light emitting light guide plate 1015 through reflection by the micro optical element 1016 and reflection by the light reflecting sheet 1017.
- each color light beam (that is, the first light beam L91 and the second light beam L92) propagates in the surface light-emitting light-guiding plate 1015 with an equal angular intensity distribution. Therefore, the illumination light L94 emitted from the surface light-emitting light guide plate 1015 becomes substantially uniform white planar light having no color unevenness in a plane parallel to the xy plane.
- the control unit 1021 controls the light source driving unit 1023 to adjust the ratio between the intensity of the first light beam L91 and the intensity of the second light beam L92, thereby adjusting the luminance and color of the light emitting surface 1015a.
- the surface light source device 1900 of the ninth embodiment includes the first light source 1018, the second light source 1901, and the diffuse reflection member 1902.
- the first light source 1018 is disposed at a position facing the light incident surface (side surface) 1015 c of the surface light-emitting light guide plate 1015.
- the second light source 1901 is disposed at a position closer to the back surface 1015 b than the light incident surface 1015 c of the surface emitting light guide plate 1015.
- the diffuse reflection member 1902 functions as an optical path changing member that guides the second light ray L92 to the light incident surface 1015c.
- the surface light source device 1900 of the ninth embodiment uses the diffuse reflection member 1902 to change the traveling direction of the second light ray L12 to the direction toward the light incident surface 1015c of the surface light-emitting light guide plate 1015.
- the diffuse reflection member 1102 has a function as an optical path changing member. Therefore, the thickness of the surface light-emitting light guide plate 1015 can be reduced as compared with the conventional configuration in which two types of light sources arranged in the thickness direction of the surface light-emitting light guide plate are arranged facing the light incident surface of the surface light-emitting light guide plate. .
- the diffuse reflection member 1902 is disposed closer to the front surface 1015a than the first light source 1018.
- the entire diffuse reflection member 1902 need not be arranged within the length in the z-axis direction (thickness direction of the surface emitting light guide plate 1015) of the light incident surface 1015c of the surface emitting light guide plate 1015.
- the thickness portion of the diffuse reflection member 1902 may be disposed on the front side (+ z-axis direction) from the light emitting surface 1015a, and the thickness of the surface light emitting light guide plate 1015 can be reduced as compared with the sixth to eighth embodiments. .
- the surface light source device 1900 of the ninth embodiment includes a diffuse reflection member 1902.
- the diffuse reflection member 1902 has a function as an optical path changing member.
- the diffuse reflection member 1902 shows the angular intensity distribution of the second light beam L92 just before entering the light incident surface 1015c of the surface light-emitting light guide plate 1015, and the angular intensity distribution of the first light beam L91 just before entering the light incident surface 1015c.
- the traveling direction of the second light ray L92 and the angular intensity distribution are changed so as to be closer to.
- the surface light source device 1900 of Embodiment 9 uses the diffuse reflection member 1902 to increase the angular intensity distribution of the second light ray L92 so as to approach the angular intensity distribution of the first light ray L91.
- the in-plane luminance distribution of the planar illumination light emitted from the light emitting surface 1015a through the surface emitting light guide plate 1015 by the first light beam L91 and the second light beam L92 similarly emitted through the surface emitting light guide plate 1015 are emitted.
- a difference from the in-plane luminance distribution of the planar illumination light emitted from the surface 1015a is suppressed. Thereby, the color unevenness of the surface light source device 2900 is reduced.
- the thickness of the surface light-emitting light guide plate 1015 is reduced, so that the thickness can be reduced. Further, the liquid crystal display device 3009 having the surface light source device 1900 of Embodiment 9 can reduce color unevenness of the surface light source device 1900. Therefore, the liquid crystal display device 3009 can reduce color unevenness on the display surface 1011a of the liquid crystal panel 1011 and improve image quality.
- the control unit 1021 causes the light source driving unit 1023 to adjust the luminance of the second light beam L92 and the luminance of the first light beam L91.
- the control unit 1021 adjusts the light emission amount of each light source based on the video signal. Thereby, the power consumption of the liquid crystal display device 3009 can be reduced.
- the liquid crystal display device by employing at least one type of laser light emitting element as the light source of the liquid crystal display device, it is possible to widen the color reproduction region and provide an image that is vivid and has no color unevenness.
- the local local temperature due to the heat generated by each light source can ease the rise. Thereby, the fall of the light emission efficiency of the light source by ambient temperature rise can be suppressed.
- the light emitted from the two light sources arranged at different positions is the end surface (light incident surface 1015c) of the short side of the surface light emitting light guide plate 1015.
- the structure which injects from is adopted.
- the position of the first light source 1018, the position of the second light source 1901, the position of the diffuse reflection member 1902, the arrangement and shape of the micro optical elements 1016, the end surface of the long side of the surface light-emitting light guide plate 1015 Can be used as a light incident surface.
- the first light source 1018 and the second light source 1901 are configured separately.
- the light source driving unit 1023 can individually control the outputs of the first light source 1018 and the second light source 1901 based on the image signal.
- the liquid crystal display device 3009 and the surface light emitting device 1900 can reduce power consumption.
- the liquid crystal display device 3009 and the surface light emitting device 1900 can reduce stray light and improve contrast. Note that stray light is light that travels outside the regular optical path in an optical device, and is harmful to a desired application.
- FIG. 36 is a cross-sectional view schematically illustrating another example of the light reflecting member 2002 of the surface light source device 2000 in the liquid crystal display device according to the ninth embodiment. 36, the same reference numerals are given to the same or corresponding components as those shown in FIG.
- the surface light source device 2000 shown in FIG. 36 is different from the surface light source device 1900 shown in FIG. 35 in the following points.
- the first difference is that a second light source 2001 is provided instead of the second light source 1901 shown in FIG.
- the second difference is that a cylindrical mirror 2002 is provided instead of the diffuse reflection member 1902.
- the second light source 2001 is the same as the second light source 1901 although the reference numerals are different.
- the surface light source device 2000 shown in FIG. 36 is the same as the surface light source device 2900 shown in FIG.
- the first light beam L101 is a light beam emitted from the first light source 1018.
- the first light beam L101 is the same type of light beam as the first light beam L91.
- the second light beam L102 is a light beam emitted from the second light source 2001.
- the second light beam L102 is the same type of light beam as the first light beam L92.
- the cylindrical mirror 2002 has the same configuration as the cylindrical mirror 1202 in the seventh embodiment. 36, the same effect as in the case of FIG. 35 can be obtained.
- FIG. 37 is a cross-sectional view schematically showing another example of the light reflecting member 2102 of the surface light source device 2100 in the liquid crystal display device of the ninth embodiment. 37, the same reference numerals are given to the same or corresponding components as those shown in FIG.
- the surface light source device 2100 shown in FIG. 37 is different from the surface light source device 2900 shown in FIG. 35 in the following points.
- the first difference is that a second light source 2101 is provided instead of the second light source 1901 shown in FIG.
- the second difference is that instead of the diffuse reflection member 1902 shown in FIG. 35, a light reflection mirror 2102 having a cross-sectional wave shape (having light reflection surfaces in which convex portions and concave portions are alternately continuous) is provided. is the point.
- the surface light source device 2100 shown in FIG. 37 is the same as the surface light source device 1900 shown in FIG.
- the first light beam L111 is a light beam emitted from the first light source 1018.
- the first light beam L111 is the same type of light beam as the first light beam L91.
- the second light beam L112 is a light beam emitted from the second light source 2101.
- the second light beam L112 is the same type of light beam as the first light beam L92.
- the light reflecting mirror 2102 has the same configuration as the light reflecting mirror 1302 in the seventh embodiment. Also in the example of FIG. 37, the same effect as in the case of FIG. 35 can be obtained.
- FIG. 38 is a cross-sectional view schematically showing another example of the light reflecting member 2202 of the surface light source device 2200 in the liquid crystal display device of the ninth embodiment. 38, the same reference numerals are given to the same or corresponding components as those shown in FIG.
- the surface light source device 2200 shown in FIG. 38 is different from the surface light source device 1900 shown in FIG. 35 in the following points.
- the first difference is that a second light source 2201 is provided instead of the second light source 1901 shown in FIG.
- the second difference is that a light reflecting mirror 2202 having a continuous light reflecting surface having a polygonal cross section is provided instead of the diffuse reflecting member 1902 shown in FIG.
- the surface light source device 2200 shown in FIG. 38 is the same as the surface light source device 1900 shown in FIG. In FIG.
- the first light beam L121 is a light beam emitted from the first light source 1018.
- the first light beam L121 is the same type of light beam as the first light beam L91.
- the second light beam L122 is a light beam emitted from the second light source 2201.
- the second light beam L122 is the same type of light beam as the second light beam L92.
- the light reflecting mirror 2202 has the same configuration as the light reflecting mirror 1402 in the seventh embodiment. Also in the example of FIG. 38, the same effect as in the case of FIG. 35 can be obtained.
- FIG. 39 is a cross-sectional view schematically showing a configuration of a liquid crystal display device 3013 (including a surface light source device 2300) according to the ninth embodiment.
- 40 is a diagram showing a configuration in the vicinity of the light incident surface 1015c of the surface light-emitting light-guiding plate 1015 of the surface light source device (backlight unit) 2300 shown in FIG. 39 and 40, the same reference numerals are given to the same or corresponding components as those shown in FIG.
- the liquid crystal display device 3013 and the surface light source device 2300 of Embodiment 9 are different from the liquid crystal display device 3006 and the surface light source device 1600 of Embodiment 8 in the order of arrangement of the first light source 1018 and the cylindrical mirror 2302 in the + z-axis direction.
- the cylindrical mirrors 1602, 1702, 1802 and the first light source 1018 are arranged in the order of the cylindrical mirrors 1602, 1702, 1802 and the first light source 1018 in the + z-axis direction.
- the cylindrical mirrors 1602, 1702, 1802 and the first light source 1018 are arranged at positions facing the light incident surface 1015 c of the surface emitting light guide plate 1015.
- the cylindrical mirror 1602 has a function as a light reflecting member.
- the cylindrical mirror 2302 and the first light source 1018 are arranged in the order of the first light source 1018 and the cylindrical mirror 2302 in the + z-axis direction.
- the shape of the light reflecting surface 2302a of the cylindrical mirror 2302 in FIG. 39 is the same as the shape of the light reflecting surface 1602a of the cylindrical mirror 1602 in FIG.
- the liquid crystal display device 3013 and the surface light source device 2300 are the same as the liquid crystal display device 3006 and the surface light source device 1600 of the eighth embodiment.
- the second light source 2301 has the same configuration, shape and function as the second light source 1601 in the eighth embodiment.
- the light source light guide member 2310 has the same configuration, shape, and function as the light source light guide member 1610 in the eighth embodiment.
- the second light source 2301 is disposed to face the light incident end 2310a of the light guide member 2310 for the light source.
- the light reflecting surface 2302a of the cylindrical mirror 2302 has the same shape and function as the light reflecting surface 1202a of the cylindrical mirror 1202 shown in FIG.
- the second light beam L132 emitted from the light emitting surface 2310c of the light guide member 2310 for the light source travels toward the light reflecting surface 2302a of the cylindrical mirror 2302, is reflected by the light reflecting surface 2302a, and travels in the traveling direction in the surface emitting light guide plate 1015. Directed toward the light incident surface 1015c (directed substantially in the + x-axis direction).
- the full width at half maximum of the angular intensity distribution of the second light ray L132 reflected by the light reflecting surface 2302a of the cylindrical mirror 2302 increases. Thereby, the angular intensity distribution of the second light ray L132 is brought closer to the angular intensity distribution of the first light ray L131.
- the first light source 1018 is disposed within the thickness range of the surface-emitting light guide plate 1015.
- the thickness of the surface light-emitting light-guiding plate 1015 is the length of the light incident surface (side surface) 1015c in the z-axis direction. Further, the position of the first light source 1018 in the x-axis direction is set so as not to block the optical path of the second light beam L132.
- the optical path of the second light beam L132 is an optical path from the second light beam L132 to the light reflecting surface 2302a of the cylindrical mirror 2302 from the light emitting surface 2310c of the light source light guide member 2310.
- the first light beam L131 emitted from the first light source 1018 travels (substantially in the + x axis direction) toward the light incident surface 1015c of the surface light-emitting light-guiding plate 1015.
- the first light beam L131 enters the surface light-emitting light guide plate 1015 from the light incident surface 1015c of the surface light-emitting light guide plate 1015.
- the first light beam L131 emitted from the first light source 1018 travels in a direction (substantially + x-axis direction) toward the light incident surface 1015c of the surface emitting light guide plate 1015.
- the second light beam L132 emitted from the second light source 2301 enters the light source light guide member 2310 from the light incident end 2310a of the light source light guide member 2310.
- the second light ray L132 repeats total reflection at the interface between the light source light guide member 2310 and the air layer and propagates while being confined in the light source light guide member 2310.
- the angular intensity distribution of the second light ray L132 is stored. Therefore, the angular intensity distribution of the second light beam L132 emitted from the light emitting surface 2310c is equal to the angular intensity distribution of the second light beam L132 emitted from the second light source 2301.
- the full width at half maximum of each angular intensity distribution is the same angle. For example, the full width at half maximum of each angular intensity distribution is 5 °.
- the second light beam L132 emitted from the light emitting surface 2310c of the light guide member 2310 for the light source travels toward the light reflecting surface 2302a of the cylindrical mirror 2302.
- the traveling direction of the second light beam L132 is changed by the cylindrical mirror 2302 to a direction (substantially + x-axis direction) toward the light incident surface 1015c of the surface light-emitting light guide plate 1015. Further, due to the reflection at the light reflecting surface 2302a, the full width at half maximum of the angular intensity distribution of the second light ray L132 increases.
- the first light beam L131 and the second light beam L132 that have entered the light incident surface 1015c of the surface light-emitting light guide plate 1015 are mixed to be white light (mixed light beam L133) by propagating through the mixed region 1015e.
- the mixed region 1015e is provided in the vicinity of the light incident surface 1015c of the surface emitting light guide plate 1015.
- the mixed light beam L133 is emitted toward the liquid crystal panel 1011 as planar illumination light L134 from the light emitting surface 1015a of the surface light emitting light guide plate 1015 through reflection on the micro optical element 1016 or reflection by the light reflecting sheet 1017.
- the controller 1021 controls the light source driver 1023 to adjust the ratio between the intensity of the first light beam L131 and the intensity of the second light beam L132, thereby adjusting the luminance and color of the light emitting surface 1015a.
- the same effect as in the case of FIG. 35 can be obtained.
- the first light source 1018 and the second light source 2301 can be disposed at positions separated from each other.
- LED elements or laser light emitting elements are employed.
- an LED element and a laser light emitting element have an electric-light conversion efficiency of 10 to 50%, and energy that is not converted into light becomes heat.
- these heat sources are concentrated in a narrow area.
- the heat dissipation capability decreases, and the ambient temperature of the first light source 1018 and the second light source 2301 increases.
- the luminous efficiency of these light sources decreases as the ambient temperature increases.
- the first light source 1018 and the second light source 2301 are arranged apart from each other. For this reason, a heat source disperse
- the laser light emitting element has a large reduction in light emission efficiency and a large amount of spectrum shift with respect to temperature change. By separating the laser light emitting element from one heat source and disposing it at one place, it is possible to efficiently provide a cooling mechanism or the like.
- the liquid crystal display device 3013 in FIG. 39 can increase the number of light sources while suppressing an increase in the thickness of the liquid crystal display device 3013 even when a plurality of different types of light sources are provided. . Therefore, a liquid crystal display device 3013 that can achieve both high brightness and thinness can be realized.
- the surface emitting light guide plate that uses the light from a plurality of types of light sources as a surface light source is shared, an increase in weight and cost can be suppressed.
- the surface light source is a light source that emits light from the entire arbitrary plane, and the surface light source here represents light emitted from the entire light emitting surface 1015a.
- the in-plane luminance distribution is a distribution indicating the level of luminance with respect to a two-dimensional position on an arbitrary plane. When these light sources have different spectra, color unevenness can be suppressed.
- FIG. 41 is a cross-sectional view schematically showing a configuration of another example of the liquid crystal display device 3014 (including the surface light source device 2400) in FIG. 41, the same reference numerals are given to the same or corresponding components as those shown in FIG.
- the liquid crystal display device 3014 and the surface light source device 2400 in FIG. 41 are different from the liquid crystal display device 3013 and the surface light source device 2300 in FIG. 39 in the following points.
- the first difference is the position of the second light source 2401.
- the second difference is the shape and arrangement of the light guide member 2410 for the light source.
- the light source light guide member 2410 functions as an optical path changing member.
- liquid crystal display device 3014 and the surface light source device 2400 shown in FIG. 41 are the same as the liquid crystal display device 3013 and the surface light source device 2300 shown in FIG.
- the light source light guide member 2410 has the same configuration and shape as the light source light guide plate 1710 of the surface light source device 1700 shown in FIG.
- the light guide member for light source 2410 is inclined with respect to the xy plane. That is, the light incident end 2410a is arranged farther from the light reflecting sheet 1017.
- the second light source 2401 is disposed on the back surface side ( ⁇ z-axis direction) of the light reflecting sheet 1017. The second light source 2401 is disposed so as to face the light incident end 2410a of the light guide member 2410 for the light source.
- a first light beam L141 is a light beam emitted from the first light source 1018.
- the first light beam L141 is the same type of light beam as the first light beam L91.
- the second light beam L142 is a light beam emitted from the second light source 2401.
- the second light beam L142 is the same type of light beam as the first light beam L92.
- the cylindrical mirror 2402 has the same configuration as the cylindrical mirror 1602 in the eighth embodiment. Also in the example of FIG. 41, the same effect as in the case of FIG. 39 can be obtained.
- a surface light source device 2500 shown in the tenth embodiment is a surface light source device corresponding to local dimming.
- Local dimming is a dimming control method for controlling a plurality of light emitting elements independently. With local dimming, it is possible to perform control such that the light source in the area of the black portion of the image on the screen does not emit light, and the light source in the area of the bright portion of the image emits light. By such control, for example, even when the entire screen is a dark image, the contrast ratio can be increased by turning on the backlight darkly only at a specific dark place on the screen.
- FIG. 42 is a configuration diagram schematically showing an example of the configuration of the liquid crystal display device 4000 (including the surface light source device 2500) of the tenth embodiment.
- FIG. 43 is a block diagram showing a configuration of a control system of liquid crystal display device 4000 of the tenth embodiment. 42 and 43, the same reference numerals are given to the same or corresponding components as those shown in FIG. 10 of the third embodiment.
- the liquid crystal display device 4000 is a transmissive display device.
- the light guide member 6 in the third embodiment is made of an integral member
- the light guide member 60 in the tenth embodiment is made up of an arbitrary number of light guide elements.
- the light source driving unit 13 in the third embodiment collectively controls driving of a plurality of light emitting elements belonging to the first light source.
- the light source driving unit 13 collectively controls driving of a plurality of light emitting elements belonging to the second light source.
- the light source driving unit 130 according to the tenth embodiment performs drive control by assembling an arbitrary number of light source elements included in the first light source.
- the light source driving unit 130 controls driving by assembling an arbitrary number of light source elements included in the second light source.
- the liquid crystal display device 4000 differs from the third embodiment in the following two points.
- the first difference is that the light guide member 60 includes an arbitrary number of light guide elements.
- the second difference is that drive control is performed by assembling an arbitrary number of light source elements included in the light source.
- the points other than the first difference and the second difference are the same as in the third embodiment.
- the tenth embodiment differs from the first and second embodiments in the following points in addition to the first and second differences described above.
- the third difference is that the light source 309 is a light source composed of a laser light emitting element.
- the points other than the first difference, the second difference, and the third difference are the same as in the first and second embodiments.
- the arbitrary number of light guide elements constituting the light guide member 60 of the tenth embodiment are the light guide member 6 in FIG. 1, the first light guide member 106 and the second light guide member 107 in FIG. 7, the light guide member 106 in FIG. 8, the light guide member 6 in FIG. 10, the light guide member 6 in FIG. 10, and the light guide member 406 in FIG. 12 can be realized by dividing it into an arbitrary number.
- FIG. 44 is a conceptual diagram of the liquid crystal display device 4000 according to the tenth embodiment when viewed in the ⁇ z-axis direction.
- the light guide member 60 includes five light guide elements 60a, 60b, 60c, 60d, and 60e.
- the light guide elements 60a, 60b, 60c, 60d, and 60e are substantially equal to the shape obtained by dividing the light guide member 6 of Embodiment 3 into five equal parts in the Y-axis direction. That is, the light guide elements 60a, 60b, 60c, 60d, and 60e have the same shape.
- the light guide elements 60a, 60b, 60c, 60d, and 60e are arranged at equal intervals in the Y-axis direction.
- the light guide elements 60a, 60b, 60c, 60d, and 60e have the same position in the x-axis direction and the z-axis direction.
- the light guide elements 60a, 60b, 60c, 60d, and 60e are, for example, plate-like members having a thickness of 2 mm.
- the total length in the Y-axis direction of the light guide member 6 composed of the light guide members 60a, 60b, 60c, 60d, and 60e is equal to or shorter than that of the surface light-emitting light guide plate 4.
- the light guide elements 60a, 60b, 60c, 60d, and 60e are made of a transparent material such as an acrylic resin (for example, PMMA).
- the first light source 208 is a light source device in which a plurality of LED elements arranged one-dimensionally in the y-axis direction.
- the plurality of LED elements included in the first light source 208 are divided into sets having the same number in the y-axis direction.
- the number of sets is an arbitrary number. In FIG. 44, the number of LED elements included in one set is four.
- FIG. 45 is a conceptual diagram of the liquid crystal display device 4000 according to the tenth embodiment when viewed in the + z-axis direction.
- the display surface 1a of the liquid crystal panel is divided into regions A, B, C, D, and E.
- the areas A, B, C, D, and E are determined in correspondence with the positions where the light guide elements 60a, 60b, 60c, 60d, and 60e are arranged.
- a first light source set for illuminating the area A is a first light source 208a.
- the first set of light sources that illuminate the region B is the first light source 208b.
- a set of first light sources that illuminate the region C is a first light source 208c.
- the first light source set that illuminates the region D is the first light source 208d.
- a set of first light sources that illuminate the region E is a first light source 208e.
- the five LED elements constituting the first light source 208 are individually driven and controlled for each group.
- the second light source 309 is a light source device in which a plurality of laser light emitting elements are arranged one-dimensionally in the y-axis direction.
- the plurality of laser light emitting elements included in the second light source 309 are divided into sets having the same number in the y-axis direction.
- the number of sets is an arbitrary number. In FIG. 44, the number of laser light emitting elements included in one set is three.
- a group of second light sources that illuminate the area A is a second light source 309a.
- a group of second light sources that illuminate the region B is a second light source 309b.
- a group of second light sources that illuminate the region C is a second light source 309c.
- a group of second light sources that illuminate the region D is a second light source 309d.
- a group of second light sources that illuminate the region E is a second light source 309e.
- the five LED elements constituting the second light source 309 are individually driven and controlled for each group.
- the light emitted from the second light source 309a in the region A enters the light guide element 60a.
- the second light source 309 a in the region A is a light source included in the second light source 309.
- the light emitted from the second light source 309b in the region B enters the light guide element 60b.
- the light emitted from the second light source 309c in the region C enters the light guide element 60c.
- the light emitted from the second light source 309d in the region D enters the light guide element 60d.
- the light emitted from the second light source 309e in the region E enters the light guide element 60e.
- the number of light guide elements 60 is equal to the number of LED elements constituting the first light source 208. Further, the number of light guide elements 60 is equal to the number of sets of laser light emitting elements constituting the second light source 309.
- the first light source 208 uses an LED element.
- the LED element of the first light source 208 emits a blue-green first light beam 281.
- Blue-green light is light obtained by mixing blue light and green light.
- the second light source 309 uses a laser light emitting element.
- the laser light emitting element of the second light source 309 emits a red second light ray 391.
- the wavelength width of the laser beam is narrow. That is, the laser light has high color purity. For this reason, the red color purity is improved by using a laser emitting element of red light. That is, the color reproduction range of the display color is widened.
- FIG. 45 is a conceptual diagram of the liquid crystal display device 4000 according to the tenth embodiment when viewed in the + z-axis direction.
- the liquid crystal display element 1 is divided into regions A to E.
- the number of regions corresponds to the number of light guide elements 60a, 60b, 60c, 60d, 60e. Further, the number of regions corresponds to the number of LED element sets 208 a, 208 b, 208 c, 208 d, and 208 e constituting the first light source 208.
- the number of regions corresponds to the number of laser light emitting element sets 309a, 309b, 309c, 309d, and 309e constituting the second light source 309.
- the LED element sets 208a, 208b, 208c, 208d, and 208e constituting the first light source 208 are individually driven and controlled for each set.
- the laser light emitting element sets 309a, 309b, 309c, 309d, and 309e constituting the second light source 309 are individually driven and controlled for each set. For this reason, area control for controlling the luminance for each area of the screen is possible. Area control is local dimming.
- the area control it is possible to reduce the brightness of the LED element sets 208a, 208b, 208c, 208d, and 208e in the corresponding area in the dark part of the screen.
- the dark part of the screen is composed of a set 309a of the laser light emitting element in the corresponding regions, 309b, 309c, 309d, and can decrease the brightness of 309e. Therefore, the liquid crystal display device 4000 can improve the contrast in the screen. Further, the liquid crystal display device 4000 can reduce power consumption.
- the area control when switching images, it is possible to turn off the set of LED elements corresponding to the region, it is possible to turn off the pair of laser light emitting element corresponding to that area.
- the image switching time is a blanking period, which is a period from the end of one scanning line on the television screen to the next scanning line. During this blanking period, no image is displayed.
- the liquid crystal display device 4000 can reduce the influence of the afterimage by turning off the LED element set in the corresponding region and turning off the laser light emitting element set.
- region A will be described.
- the second light ray 391a in the region A enters the light guide element 60a from the end face 661a.
- the second light ray 391a in the region A propagates in the ⁇ x axis direction in the light guide element 60a. Thereafter, the second light ray 391a is reflected by the end face 661c and changes its traveling direction in the + z-axis direction. Thereafter, the second light ray 391a is reflected by the end face 661d and changes its traveling direction in the + x-axis direction.
- the second light source 309 a in the region A is included in the second light source 309.
- the second light ray 391a is emitted from the second light source 309a in the region A.
- the first light ray 281a in the region A emitted from the first light source 208a in the region A travels in the + x axis direction.
- the first light ray 281a in the region A enters the light guide part 662b of the light guide element 60a.
- the first light ray 281a in the region A is mixed with the second light ray 391a in the light guide portion 662b of the light guide element 60a.
- the first light ray 281 a in the region A is incident on the surface-emitting light guide plate 4.
- the first light ray 281a in the region A and the second light ray 391a in the region A are mixed to become a light ray 343a.
- the first light beam 281a in the region A and the second light beam 391a in the region A are incident on the surface light-emitting light guide plate 4 from the portion corresponding to the region A of the light incident surface 41a and propagate in the + x-axis direction.
- the light incident surface 41 a is an end surface of the surface emitting light guide plate 4.
- the light beam 343 a is converted into illumination light 344 by the micro optical element 42. Thereafter, the illumination light 344 is emitted toward the back surface 1 b of the liquid crystal panel 1. At this time, the illumination light 344 is light that mainly illuminates the region A.
- the second light ray 391b in the region B enters the light guide element 60b from the end face 661a.
- the second light ray 391b in the region B propagates in the ⁇ x axis direction in the light guide element 60b. Thereafter, the second light ray 391b is reflected by the end face 661c and changes the traveling direction in the + z-axis direction. Thereafter, the second light ray 391b is reflected by the end face 661d and changes its traveling direction in the + x-axis direction.
- the second light source 309b in the region B is included in the second light source 309. The second light ray 391b is emitted from the second light source 309b in the region B.
- the second light beam 391b in the region B enters the surface light-emitting light guide plate 4 from the end surface 41a corresponding to the region B together with the first light beam 281b in the region B, and becomes illumination light mainly illuminating the region B.
- the first light beam 281b in the region B is a light beam emitted from the first light source 208b in the region B.
- the second light ray 391c in the region C enters the light guide element 60c from the end face 661a.
- the second light ray 391c in the region C propagates in the ⁇ x axis direction in the light guide element 60c. Thereafter, the second light ray 391c is reflected by the end face 661c and changes its traveling direction in the + z-axis direction. Thereafter, the second light ray 391c is reflected by the end face 661d and changes its traveling direction in the + x-axis direction.
- the second light source 309c in the region C is included in the second light source 309. The second light ray 391c is emitted from the second light source 309c in the region B.
- the second light ray 391c in the region C enters the surface light-emitting light guide plate 4 from the end surface 41a corresponding to the region C together with the first light ray 281c in the region C, and becomes illumination light mainly illuminating the region C.
- the first light ray 281c in the region C is a light ray emitted from the first light source 208c in the region C.
- the second light ray 391d in the region D enters the light guide element 60d from the end face 661a.
- the second light ray 391d in the region D propagates in the light guide element 60d in the ⁇ x-axis direction. Thereafter, the second light ray 391d is reflected by the end face 661c and changes its traveling direction in the + z-axis direction. Thereafter, the second light ray 391d is reflected by the end face 661d and changes its traveling direction in the + x-axis direction.
- the second light source 309d in the region D is included in the second light source 309. The second light ray 391d is emitted from the second light source 309d in the region B.
- the second light ray 391d in the region D enters the surface light-emitting light guide plate 4 from the end surface 41a corresponding to the region D together with the first light ray 281d in the region D, and becomes illumination light mainly illuminating the region D.
- the first light ray 281d in the region D is a light ray emitted from the first light source 208d in the region D.
- the second light ray 391e in the region E enters the light guide element 60e from the end face 661a.
- the second light ray 391e in the region E propagates in the ⁇ x axis direction in the light guide element 60e. Thereafter, the second light ray 391e is reflected by the end face 661c and changes the traveling direction in the + z-axis direction. Thereafter, the second light ray 391e is reflected by the end face 661d and changes its traveling direction in the + x-axis direction.
- the second light source 309e in the region E is included in the second light source 309. The second light ray 391e is emitted from the second light source 309e in the region E.
- the second light beam 391e in the region E enters the surface light-emitting light guide plate 4 from the end surface 41a corresponding to the region E together with the first light beam 281e in the region E, and becomes illumination light mainly illuminating the region E. .
- the first light ray 281e in the region E is a light ray emitted from the first light source 208e in the region E.
- the control unit 11 controls the light source driving unit 130 to set the LED elements 208a, 208b, 208c, 208d, and 208e that constitute the first light source 208.
- the brightness can be adjusted for each set, and the brightness can be adjusted for each set of laser light emitting element sets 309a, 309b, 309c, 309d, and 309e constituting the second light source 309. That is, the liquid crystal display device 4000 can adjust the ratio between the luminance of the first light source 208 and the luminance of the second light source 309.
- the liquid crystal display device 4000 can also adjust the luminance for each of the regions A, B, C, D, and E.
- the control unit 11 adjusts the light emission amount of each light source 208, 309 based on the video signal, and adjusts the light emission amount of each group 208a, 208b, 208c, 208d, 208e, 309a, 309b, 309c, 309d, 309e.
- the light emission amount of the first light source 208a in the region A can be lowered and the light emission amount of the second light source 309a in the region A can be lowered.
- the region B is reddish
- the light emission amount of the first light source 208b in the region B can be reduced.
- a reddish image is a reddish image.
- the image is reddish.
- the power consumption of the liquid crystal display device 4000 can be reduced by adjusting the light emission amount of the light source for each region according to the image.
- the in-screen contrast of the liquid crystal display device 4000 can be improved by adjusting the light emission amount of the light source for each region in accordance with the image.
- the luminance control for each region can be performed more finely.
- Each light guide element 60a, 60b, 60c, 60d, 60e and each set of laser light emitting elements 309a, 309b, 309c, 309d, 309e are arranged correspondingly.
- the second light rays 391a, 391b, 391c, 391d, and 391e emitted from the laser light emitting element sets 309a, 309b, 309c, 309d, and 309e are incident on the corresponding light guide elements 60a, 60b, 60c, 60d, and 60e. To do.
- the second light ray 391 propagates in the ⁇ x-axis direction while being totally reflected at the interface between the light guide element 60 and the air layer. For this reason, the second light beam 391a, 391b, 391c, 391d, 391e travels in the corresponding light guide element 60a, 60b, 60c, 60d, 60e, while another laser light emitting element of the same set adjacent to it. It overlaps with light.
- the laser light emitting elements of the same set are three laser elements corresponding to the same light guide element 60 shown in FIG.
- the second light rays 391a, 391b, 391c, 391d, and 391e are light rays emitted from the laser light emitting element sets 309a, 309b, 309c, 309d, and 309e.
- the laser beams overlap to form linear light with a uniform luminance distribution in the Y-axis direction of each light guide element.
- the second light beams 391a, 391b, 391c, 391d, and 391e emitted from the sets 309a, 309b, 309c, 309d, and 309e of the respective laser light emitting elements are the corresponding light guide elements 60a, 60b, 60c, 60d, and 60e. It becomes linear light during propagation.
- the linear light is light having a uniform luminance distribution with substantially the same length as the length of the light guide element 60 in the Y-axis direction.
- the light guide member 60 is divided into light guide elements 60a, 60b, 60c, 60d, and 60e, and the second light source 309 is divided into laser light emitting element groups 309a, 309b, 309c, and 309d for each region. , 309e.
- the second light rays 391a, 391b, 391c, 391d, and 391e emitted from the sets 309a, 309b, 309c, 309d, and 309e of the respective laser light emitting elements are linear light having a uniform luminance distribution for each region. And enters the surface-emitting light guide plate 4.
- the group of laser light emitting elements 309a, 309b, 309c, 309d, and 309e is turned on for each region, the light does not leak to the other adjacent regions A, B, C, D, and E, and the accuracy is improved. Good area control is possible.
- an arbitrary number of light guide elements 60, an arbitrary number of sets of LED elements, and an arbitrary number of sets of laser light emitting elements are employed.
- An arbitrary number of LED element groups can modulate the light emission amount for each group.
- any number of sets of laser light emitting elements can modulate the light emission amount for each set.
- Each set of LED elements is installed at a position corresponding to each light guide element 60 so as to illuminate an arbitrary area of the liquid crystal display device 4000.
- Each set of laser light emitting elements is installed at a position corresponding to each light guide element 60 so as to illuminate an arbitrary region of the liquid crystal display device 4000.
- the liquid crystal display device 4000 can adjust the brightness for each region according to the image. Thereby, an improvement in contrast can be realized. In addition, power consumption can be reduced.
- the liquid crystal display device 4000 has a configuration in which the second light source 309 is disposed on the back surface of the liquid crystal display element 1 and is incident on the surface light-emitting light guide plate 4 through the light guide member 60.
- the light guide member 60 is divided into an arbitrary number of light guide elements 60a, 60b, 60c, 60d, and 60e, thereby realizing area control without light leaking to other adjacent regions. . Therefore, the liquid crystal display device 4000 of the tenth embodiment is effective as a configuration for controlling lighting for each area.
- the number of light guide elements 60a, 60b, 60c, 60d, and 60e constituting the light guide member 60 is five.
- the number of light guide elements is determined according to the number of areas that are individually lit.
- the number of light guide elements is the number of divisions of the light guide member 60.
- a red laser light emitting element is used for the second light source 309.
- the present invention is not limited to this.
- red laser light emitting elements having different wavelength peaks can be used.
- a laser light emitting element that emits blue or green light can be used. Note that the light from the first light source 208 needs to be mixed with the light from the second light source 309 to become white light. That is, the light from the first light source 208 is complementary to the light from the second light source 309.
- FIG. 46 is a cross sectional view schematically showing an example of the configuration of the liquid crystal display device 4001 (including the surface light source device 2600) according to the eleventh embodiment.
- constituent elements that are the same as or correspond to those shown in FIG. 42 (Embodiment 10) are assigned the same reference numerals.
- the liquid crystal display device 4001 is a transmissive display device.
- the light guide member 706 of the eleventh embodiment is composed of an arbitrary number of light guide elements 706a, 706b, 706c, 706d, and 706e having the same shape as the light guide element 60 in the tenth embodiment.
- One end face of the light guide elements 706a, 706b, 706c, 706d, and 706e constituting the light guide member 706 is formed of a diffuse reflection surface.
- the end surface 761d is formed of a diffuse reflection surface.
- the liquid crystal display device 4001 is the same as the tenth embodiment except that one end face of the light guide elements 706a, 706b, 706c, 706d, and 706e is a diffuse reflection surface.
- the eleventh embodiment differs from the fifth embodiment in that the light guide member 506 is divided into light guide elements.
- the light guide member 506 of the fifth embodiment is integrally formed.
- the light guide member 706 according to the eleventh embodiment includes divided light guide elements 706a, 706b, 706c, 706d, and 706e.
- the embodiment 11 can take the forms of FIGS. 6 and 7 other than the embodiment of FIG. 1 of the first embodiment.
- the form shown in FIG. 12 of the fourth embodiment can be adopted.
- the diffuse reflection surface provided on the end surface 761d of the eleventh embodiment is provided on the end surface 61d in FIG. 1, provided on the end surface 171c in FIG. 6, provided on the end surface 141d in FIG. It can be provided on the end surface 61d. In FIG. 10, it can be provided on the end surface 61d. In FIG. 12, it can be provided on the end surface 461d.
- the arbitrary number of light guide elements constituting the light guide member 706 of the eleventh embodiment can be realized by dividing the light guide member 6 into an arbitrary number in the embodiment shown in FIG. In the embodiment shown in FIG. 7, it can be realized by dividing the first light guide member 106 and the second light guide member 107 into an arbitrary number. In the embodiment shown in FIG. In the embodiment shown in FIG. 8, it can be realized by dividing the light guide member 6 into an arbitrary number. In the embodiment shown in FIG. This can be realized by dividing into a number, and in the embodiment shown in FIG. 12, it can be realized by dividing the light guide member 406 into an arbitrary number.
- FIG. 47 is a conceptual diagram of the liquid crystal display device 4001 according to the eleventh embodiment as viewed in the ⁇ z-axis direction.
- the light guide member 706 includes five light guide elements 706a, 706b, 706c, 706d, and 706e.
- the light guide elements 706a, 706b, 706c, 706d, and 706e have substantially the same shape as the light guide member 506 of Embodiment 5 divided into five equal parts in the y-axis direction. That is, the light guide elements 706a, 706b, 706c, 706d, and 706e have the same shape.
- the light guide elements 706a, 706b, 706c, 706d, and 706e are arranged at equal intervals in the y-axis direction.
- the light guide elements 706a, 706b, 706c, 706d, and 706e have the same position in the x-axis direction and the z-axis direction.
- the light guide elements 706a, 706b, 706c, 706d, and 706e are, for example, plate-like members having a thickness of 2 mm.
- the total length of the light guide member 706 in the y-axis direction is equal to or shorter than that of the surface light-emitting light guide plate 4.
- the light guide member 706 includes light guide elements 706a, 706b, 706c, 706d, and 706e.
- the light guide elements 706a, 706b, 706c, 706d, and 706e are made of a transparent material such as acrylic resin (for example, PMMA).
- the first light source 208 has a plurality of LED elements arranged one-dimensionally in the y-axis direction.
- the LED elements of the first light source 208 are divided into an arbitrary number of groups having the same number in the y-axis direction.
- the first light source 208 includes the first light source 208a in the region A, the first light source 208b in the region B, the first light source 208c in the region C, and the region D.
- the first light source 208d and the first light source 208e in the region E are divided into five groups.
- the five sets of LED elements constituting the first light source 208 are individually driven and controlled.
- the second light source 309 has a plurality of laser light emitting elements arranged one-dimensionally in the y-axis direction.
- the laser light emitting elements of the second light source 309 are divided into an arbitrary number of sets having the same number in the y-axis direction.
- the second light source 309 includes the second light source 309a in the region A, the second light source 309b in the region B, the second light source 309c in the region C, and the region D.
- the second light source 309d and the second light source 309e in the region E are divided into five groups. The five sets of laser light emitting elements constituting the second light source 309 are individually driven and controlled.
- the second light source 309 includes a second light source 309a, a second light source 309b, a second light source 309c, a second light source 309d, and a second light source 309e.
- the second light ray 391a emitted from the second light source 309a in the region A enters the light guide element 706a from the light incident surface 761a.
- the second light ray 391b emitted from the second light source 309b in the region B enters the light guide element 706b from the light incident surface 761a.
- the second light beam 391c emitted from the second light source 309c in the region C enters the light guide element 706c from the light incident surface 761a.
- the second light beam 391d emitted from the second light source 309d in the region D enters the light guide element 706d from the light incident surface 761a.
- the second light ray 391e emitted from the second light source 309e in the region E enters the light guide element 706e from the light incident surface 761a.
- the number of light guide elements 706 a, 706 b, 706 c, 706 d, and 706 e is equal to the number of LED element sets 208 a, 208 b, 208 c, 208 d, and 208 e constituting the first light source 208. Further, the number of the light guide elements 706a, 706b, 706c, 706d, and 706e is equal to the number of sets of the laser light emitting elements 309a, 309b, 309c, 309d, and 309e constituting the second light source 309.
- the LED element of the first light source 208 emits a blue-green first light beam 281.
- Blue-green light is light obtained by mixing blue light and green light.
- the laser light emitting element of the second light source 309 emits a red second light beam 391.
- the wavelength width of the laser beam is narrow. That is, the laser beam has high color purity. For this reason, the red color purity is improved by using a laser emitting element of red light. That is, the color reproduction range of the display color is widened.
- FIG. 46 is a block diagram schematically showing an example of the configuration of the liquid crystal display device 4001 (including the surface light source device 2600) according to the tenth embodiment.
- the manner in which each light beam is transmitted will be described with reference to FIG.
- the first light beam 281 emitted from the first light source 208 has a wide angular intensity distribution.
- the first light source 208a in the region A emits a second light ray 281a having a wide angular intensity distribution.
- the first light source 208 a in the region A is included in the first light source 208.
- the first light ray 281a emitted from the first light source 208a in the region A travels in the + x axis direction. Thereafter, the first light beam 281a is incident on the light guide portion 762b of the light guide element 706a.
- the second light source 309a in the area A included in the second light source 309 emits a light ray 391a.
- the second light source 309 a in the region A is included in the second light source 309.
- the second light ray 391a enters the light guide element 706a from the light incident surface 761a.
- the second light ray 391a repeats total reflection at the interface between the light guide element 706a and the air layer, and travels in the ⁇ x axis direction within the light guide element 706a.
- the second light ray 391a is reflected by the end face 761c and travels in the + z-axis direction. At this time, the angular intensity distribution of the second light ray 391a is stored.
- the angular intensity distribution of the second light ray 391a reaching the diffuse reflection surface 761d is equal to the angular intensity distribution of the second light ray 391a when emitted from the second light source 309a.
- the full width at half maximum of the angular intensity distribution of the second light ray 391a reaching the diffuse reflection surface 761d is equal to the full width at half maximum of the angular intensity distribution of the second light ray 391a when emitted from the second light source 309a.
- the full width at half maximum of the angular intensity distribution is, for example, 5 °.
- the second light ray 391a is reflected by the diffuse reflection surface 761d and changes the traveling direction in the direction of the light incident surface 41a of the surface light-emitting light guide plate 4 (substantially + x-axis direction).
- the second light ray 391a is diffused. Thereby, the full width at half maximum of the angular intensity distribution of the second light ray 391a is increased.
- the light emitted from the second light source 309b in the region B can propagate through the light guide element 706b to increase the full width at half maximum of the angular intensity distribution.
- the light emitted from the second light source 309c in the region C can propagate through the light guide element 706c, thereby increasing the full width at half maximum of the angular intensity distribution.
- Light emitted from the second light source 309d in the region D can propagate through the light guide element 706d to increase the full width at half maximum of the angular intensity distribution.
- the light emitted from the second light source 309e in the region E can propagate the light guide element 706e, thereby increasing the full width at half maximum of the angular intensity distribution.
- the light source type of the first light source 208 is different from the light source type of the second light source 309. Further, the angular intensity distribution of the first light source 208 is different from the angular intensity distribution of the second light source 309.
- the first light source 208 employs an LED element.
- the second light source 309 employs a laser light emitting element. Even in such a case, the light guide member 706 can match the angular intensity distribution of the light source having a narrow angular intensity distribution with the angular intensity distribution of the light source having a wide angular intensity distribution.
- the light guide member 706 includes an in-plane luminance distribution of the surface-emitting light-guiding plate 4 generated by the first light ray 281 and an in-plane luminance distribution of the surface-emitting light-guiding light guide plate 4 generated by the second light ray 391. Can be suppressed.
- the first light beam 281 is a light beam emitted from the first light source 208.
- the second light beam 391 is a light beam emitted from the second light source 309. Accordingly, even when the first light source 208 has a spectrum different from that of the second light source 309, the liquid crystal display device 4001 can suppress color unevenness.
- the first light beam 281a propagates in the light guide element 706a, enters the surface light-emitting light guide plate 4 from a portion corresponding to the region A of the light incident surface 41a, and propagates in the surface light-emitting light guide plate 4 in the + x-axis direction.
- the second light ray 391a propagates in the light guide element 706a, enters the surface light-emitting light guide plate 4 from a portion corresponding to the region A of the light incident surface 41a, and propagates in the surface light-emitting light guide plate 4 in the + x-axis direction.
- the first light beam 281 a and the second light beam 391 a are converted into illumination light 344 by the micro optical element 42.
- the illumination light 344 is emitted toward the back surface 1b of the liquid crystal panel 1. At this time, the illumination light 344 becomes light that mainly illuminates the region A.
- the first light beam 281b propagates in the light guide element 706b, enters the surface light-emitting light guide plate 4 from a portion corresponding to the region B of the light incident surface 41a, and passes through the surface light-emitting light guide plate 4 in the + x axis. Propagate in the direction.
- the second light ray 391b propagates in the light guide element 706b, enters the surface light-emitting light guide plate 4 from a portion corresponding to the region B of the light incident surface 41a, and propagates in the surface light-emitting light guide plate 4 in the + x-axis direction.
- the first light beam 281 b and the second light beam 391 b are converted into illumination light 344 by the micro optical element 42.
- the illumination light 344 is emitted toward the back surface 1b of the liquid crystal panel 1. At this time, the illumination light 344 is light that mainly illuminates the region B.
- the first light ray 281c propagates in the light guide element 706c, enters the surface light-emitting light guide plate 4 from a portion corresponding to the region C of the light incident surface 41a, and propagates in the surface light-emitting light guide plate 4 in the + x-axis direction.
- the second light ray 391c propagates in the light guide element 706c, enters the surface light-emitting light guide plate 4 from a portion corresponding to the region C of the light incident surface 41a, and propagates in the surface light-emitting light guide plate 4 in the + x-axis direction.
- the first light beam 281 c and the second light beam 391 c are converted into illumination light 344 by the micro optical element 42.
- the illumination light 344 is emitted toward the back surface 1b of the liquid crystal panel 1. At this time, the illumination light 344 is light that mainly illuminates the region C.
- the first light beam 281d propagates in the light guide element 706d, enters the surface light-emitting light guide plate 4 from a portion corresponding to the region D of the light incident surface 41a, and propagates in the surface light-emitting light guide plate 4 in the + x-axis direction.
- the second light ray 391d propagates in the light guide element 706d, enters the surface light-emitting light guide plate 4 from a portion corresponding to the region D of the light incident surface 41a, and propagates in the surface light-emitting light guide plate 4 in the + x-axis direction.
- the first light beam 281d and the second light beam 391d are converted into illumination light 344 by the micro optical element 42.
- the illumination light 344 is emitted toward the back surface 1b of the liquid crystal panel 1. At this time, the illumination light 344 is light that mainly illuminates the region D.
- the first light ray 281e propagates in the light guide element 706e, enters the surface light-emitting light guide plate 4 from a portion corresponding to the region E of the light incident surface 41a, and propagates in the surface light-emitting light guide plate 4 in the + x-axis direction.
- the second light ray 391e propagates in the light guide element 706e, enters the surface light-emitting light guide plate 4 from a portion corresponding to the region E of the light incident surface 41a, and propagates in the surface light-emitting light guide plate 4 in the + x-axis direction.
- the first light beam 281e and the second light beam 391e are converted into illumination light 344 by the micro optical element 42.
- the illumination light 344 is emitted toward the back surface 1b of the liquid crystal panel 1. At this time, the illumination light 344 is light that mainly illuminates the region E.
- an arbitrary number of light guide elements 706a, 706b, 706c, 706d, and 706e are employed.
- an arbitrary number of LED element sets 208a, 208b, 208c, 208d, and 208e are employed.
- an arbitrary number of sets 309a, 309b, 309c, 309d, and 309e of laser light emitting elements is employed.
- the LED element groups 208a, 208b, 208c, 208d, and 208e can adjust the light emission amount for each group.
- the laser element sets 309a, 309b, 309c, 309d, and 309e can adjust the light emission amount for each set.
- the light guide elements 706 a, 706 b, 706 c, 706 d, and 706 e are installed at positions corresponding to the area of the liquid crystal display device 4001.
- the LED element sets 208 a, 208 b, 208 c, 208 d, and 208 e illuminate corresponding areas of the liquid crystal display device 4001.
- the laser light emitting element sets 309a, 309b, 309c, 309d, and 309e illuminate corresponding areas of the liquid crystal display device 4001. Therefore, the liquid crystal display device 4001 can adjust the luminance for each region according to the image. Thereby, the liquid crystal display device 4001 can improve contrast. Further, the liquid crystal display device 4001 can reduce power consumption.
- the liquid crystal display device 4001 allows the light guide member 706 to be arbitrarily placed. By dividing the light guide elements 706a, 706b, 706c, 706d, and 706e, it is difficult for light to leak into other adjacent areas, and accurate area lighting control can be realized.
- the same effect as in the tenth embodiment can be obtained.
- different types of light sources having different angular intensity distributions are employed. Even in such a case, the light guide member 706 can match the angular intensity distribution of the light source having a narrow angular intensity distribution with the angular intensity distribution of the light source having a wide angular intensity distribution. For this reason, the liquid crystal display device 4001 can suppress color unevenness.
- the eleventh embodiment is also effective as a configuration for extending the color reproduction range.
- the purpose of the eleventh embodiment is to match the angular intensity distributions of different types of light sources having different angular intensity distributions. Therefore, in Embodiment 11, the same effect can be obtained by providing the diffusion structure provided on the end surface 761d of the light guide element 706 on the other reflection surface 761c on the optical path of the second light ray 391a.
- the diffusion structure is provided in the vicinity of the light incident surface 41 a of the surface light-emitting light guide plate 4, it is possible to suppress a decrease in the amount of light of the second light source 309 incident on the surface light-emitting light guide plate 4. This is because when the diffusing structure is provided in a portion near the light incident surface 761a of the light guide member 706, the light scatters and the number of rays that do not satisfy the total reflection condition increases. This is because of the decrease. Also from this, it is preferable that the diffusion structure is provided in the vicinity of the end surface 761e of the light guide member 706. That is, it is preferable that the diffusion structure is provided in the vicinity of the light incident surface 41 a of the surface emitting light guide plate 4.
- the diffusion structure may be provided in a region where the second light ray 391a is emitted from the light guide element 706a on the end surface 761e as shown in FIG.
- a diffusion element 700 may be provided between the light guide elements 706 a, 706 b, 706 c, 706 d, and 706 e and the surface emitting light guide plate 4.
- the light guide member 706 may include the diffusing element 700 on the surface of the emission surface.
- the light guide member 706 may include the diffusing element 700 inside the light guide member 706 in the vicinity of the exit surface.
- the surface light-emitting light guide plate 4 may include a diffusing element 700 on the surface of the light incident surface 41a.
- the surface of the light incident surface 41a may be a diffusion structure.
- the surface light-emitting light guide plate 4 may include a diffusing element 700 inside the surface light-emitting light guide plate 4 in the vicinity of the light incident surface 41a.
- the diffusing element 700 and the diffusing structure diffuse not only the second light ray 391 but also the first light ray 281. .
- the change in the angular intensity distribution of the first light ray 281 is smaller than that of the second light ray 391. Therefore, even if the diffusing element 700 or the like is provided between the light guide elements 706a, 706b, 706c, 706d, and 706e and the surface light emitting light guide plate 4, the same effect as that obtained when the diffusing structure is provided on the reflecting surface 761d is obtained. be able to.
- the diffusion structure is formed on the surface of the end surface 761e.
- the diffusion structure is formed on the surface of the light incident surface 41a.
- the diffusion structure is formed on the surface of the diffusion element 700.
- the diffusion structure may be a structure in which a plurality of fine concave lenses are formed.
- the diffusion structure may be a structure in which a plurality of fine convex lenses are formed.
- the diffusion structure may be a structure in which a plurality of fine pyramid shapes are formed.
- corrugated shape was formed by the blast process may be sufficient.
- particles having a refractive index different from that of the surrounding material may be attached by painting.
- the diffusing element 700 may be an element including particles having a refractive index different from that of the surrounding material therein.
- the light guide elements 706a, 706b, 706c, 706d, and 706e have the same shape. Therefore, the same diffusion structure is adopted for each of the light guide elements 706a, 706b, 706c, 706d, and 706e.
- the number of light guide elements constituting the light guide member 706 is five. However, the present invention is not limited to this.
- the number of light guide elements 706a, 706b, 706c, 706d, and 706e is determined in accordance with the number of areas required for individual area lighting.
- the number of light guide elements 706 a, 706 b, 706 c, 706 d, and 706 e is the number of divisions of the light guide member 706.
- a red laser light emitting element is used for the second light source 309.
- the present invention is not limited to this.
- red laser light emitting elements having different wavelength peaks can be used.
- a laser light emitting element that emits blue or green light can be used. Note that the light from the first light source 208 needs to be mixed with the light from the second light source 309 to become white light. That is, the light from the first light source 208 is a complementary color of the light from the second light source 309.
- the invention is described as a backlight device of a liquid crystal display device. For this reason, the mixed light beam becomes a white light beam, but does not exclude light beams other than white light. It is possible to generate light rays other than white depending on the application of the device.
- 1 liquid crystal display element liquid crystal panel
- 1a liquid crystal panel display surface 1b liquid crystal panel back surface (back surface)
- 2 first optical sheet 3 second optical sheet
- 5, light reflection sheet 6, 106, 107, 108, 406, 408, 506, light guide member (light path changing member)
Abstract
Description
図1は、本発明に係る実施の形態1の液晶表示装置100(面光源装置200を含む)の構成の一例を概略的に示す断面図である。面光源装置200は、面発光導光板4、光反射シート5、導光部材6、第1光源8、第2光源9を有する。また、面光源装置200には、導光部材6の機能を有する構成要素108,106,107,も含まれる。説明を容易にするために、各図中にxyz直交座標系の座標軸を示す。以下の説明において、液晶表示素子(液晶パネル)1の表示面1aの短辺方向をy軸方向(図1が描かれている紙面に垂直な方向)とし、液晶パネル1の表示面1aの長辺方向をx軸方向(図1において左右方向)とし、x軸及びy軸を含む平面であるxy平面に垂直な方向をz軸方向(図1における上下方向)とする。また、図1において、左から右に向かう方向を、x軸の正方向(+x軸方向)とし、その反対方向を、x軸の負方向(-x軸方向)とする。また、図1が描かれている紙面の手前から紙面に向かう方向を、y軸の正方向(+y軸方向)とし、その反対方向を、y軸の負方向(-y軸方向)とする。さらに、図1において、下から上に向かう方向を、z軸の正方向(+z軸方向)とし、その反対方向を、z軸の負方向(-z軸方向)とする。
図8は、実施の形態2の液晶表示装置101(面光源装置201を含む)の構成の一例を概略的に示す断面図である。面光源装置201は、面発光導光板4、光反射シート5、導光部材6、第1光源208、第2光源209を有する。また、面光源装置201には、導光部材6の機能を有する構成要素も含まれる。図8において、図1(実施の形態1)に示される構成要素と同一又は対応する構成要素には、同じ符号を付す。液晶表示装置101は、透過型表示装置である。液晶表示装置101は、実施の形態1の液晶表示装置100の白色の第1光源8及び第2光源9に代えて、異なる色の第1光源208及び第2光源209を有している。液晶表示装置101は、上記の相違点以外は、実施の形態1と同じである。なお、実施の形態2においても、実施の形態1の図1の形態以外の図4、図6及び図7の形態も取り得る。
図10は、実施の形態3の液晶表示装置102(面光源装置202を含む)の構成の一例を概略的に示す断面図である。面光源装置202は、面発光導光板4、光反射シート5、導光部材6、第1光源208、第2光源209を有する。また、面光源装置202には、導光部材6の機能を有する構成要素も含まれる。図10において、図8(実施の形態2)に示される構成要素と同一又は対応する構成要素には、同じ符号を付す。液晶表示装置102は、透過型表示装置である。実施の形態2における第2光源209は、LED素子を有しているが、実施の形態3における第2光源309は、レーザ発光素子を有している。液晶表示装置102は、上記相違点以外は、実施の形態2と同じである。また、実施の形態3は、実施の形態1に対して、第1光源208及び第2光源309の構成要素において相違し、それ以外の構成要素に関しては同じである。なお、実施の形態3においても、実施の形態1の図1の形態以外の図4、図6及び図7の形態も取り得る。
図12は、実施の形態4の液晶表示装置103(面光源装置203を含む)の構成の一例を概略的に示す断面図である。面光源装置203は、面発光導光板4、光反射シート5、導光部材406、第1光源208、第2光源209を有する。また、面光源装置203には、導光部材406の機能を有する構成要素も含まれる。図12において、図10(実施の形態3)に示される構成要素と同一又は対応する構成要素には、同じ符号を付す。液晶表示装置103は、透過型表示装置である。実施の形態1~3においては、2箇所の光源から出射した光は、導光部材6で混ぜられる。その後、混ぜられた光は、面発光導光板4の内部に入射する。実施の形態4の液晶表示装置103においては、2つの光源から出射した光が別々に面発光導光板4に入射する。2つの光源は、異なる2箇所に配置されている。2箇所に配置された光源は、LED素子を用いた第1光源208とレーザ発光素子を用いた第2光源309とである。液晶表示装置103は、実施の形態3の導光部材6に代えて、新たに導光部材406を有している。液晶表示装置103は、上記相違点以外は、実施の形態3と同じである。また、実施の形態4は、実施の形態1及び2に対して、第1光源208、第2光源309及び導光部材406の構成要素において相違し、それ以外の構成要素に関しては同じである。なお、実施の形態4においても、実施の形態1の図1の形態以外の図4、図6及び図7の形態も取り得る。
図14は、実施の形態5の液晶表示装置104(面光源装置204を含む)の構成の一例を概略的に示す断面図である。面光源装置204は、面発光導光板4、光反射シート5、導光部材506、第1光源208、第2光源209を有する。また、面光源装置204には、導光部材506の機能を有する構成要素も含まれる。図14において、図10(実施の形態3)に示される構成要素と同一又は対応する構成要素には、同じ符号を付す。液晶表示装置104は、透過型表示装置である。実施の形態5の液晶表示装置104は、導光部材506の端面561dが拡散反射面で構成されている。液晶表示装置104は、上記相違点以外は、実施の形態3と同じである。また、実施の形態5は、実施の形態1及び2に対して、第1光源208及び第2光源309の構成要素において相違し、また、導光部材が拡散反射面を有する点で異なる。それ以外の構成要素に関しては、実施の形態5は、実施の形態1及び2と同じである。なお、実施の形態5においても、実施の形態1の図1の形態以外の図4、図6及び図7の形態も取り得る。また、実施の形態5においても、実施の形態4の図12の形態以外の図13の形態も取り得る。実施の形態5の端面561dに設けられた拡散反射面は、図1では端面61dに設けられ、図4では反射面183aに設けられ、図6では端面171cに設けられ、図7では端面141dに設けられ、図8では端面61dに設けられ、図10では端面61dに設けられ、図12では端面461dに設けられ、図13では反射面481cに設けられることができる。
《6-1》実施の形態6の構成
図18は、実施の形態6の液晶表示装置3001(面光源装置1100を含む)の構成を概略的に示す断面図である。面光源装置1100は、面発光導光板1015、光反射シート1017、拡散反射部材1102、第1光源1018、第2光源1101を有する。面光源装置1110は、面発光導光板1015、光反射シート1017、拡散反射部材1112、第1光源1018、第2光源1111を有する。また、図19は、図18に示される面光源装置1100を液晶パネル11側(+z軸方向)から見た概略的な平面図であり、図20は、図15に示される面光源装置1100を液晶表示装置3001の背面側(-z軸方向)から見た概略的な背面図である。
拡散反射部材1102の拡散光反射面1102aは、アクリル樹脂(例えば、PMMA(ポリメタクリル酸メチル樹脂))の表面にブラスト加工などにより乱雑な凹凸形状を形成し、その表面にアルミニウムを蒸着したものである。ただし、拡散反射部材1102の拡散光反射面1102aの構成は、上記例に限定されない。拡散光反射面1102aの構成は、拡散反射部材1102の基材として、加工性に優れたポリカーボネートなどの樹脂を用いてもよいし又は金属を用いてもよい。また、拡散反射部材1102の拡散光反射面1102aに蒸着する金属膜として、銀又は金などの反射率の高い他の金属を採用してもよい。さらに、拡散反射部材1102の拡散光反射面1102aとして、例えば、基材の表面に大きさの異なる複数のビーズを塗装し、さらにその表面に銀などの金属膜を設けたものを採用してもよい。また、拡散反射部材1102として、ポリエステル基材中に気泡構造を設けた反射フィルムを採用してもよい。この場合には、表面の凹凸構造や基材中の気泡構造を最適化することにより高い拡散反射性能を得ることができる。また、これらの拡散反射部材1102は、簡易、安価な部材であり、簡易構造かつ低コストにおいても高い画質向上効果を得ることができる。
照明光L14は、略+z軸方向に進行し、液晶パネル1011の背面1011bに向けて進む。照明光L14は、第2の光学シート1013及び第1の光学シート1012を透過して液晶パネル1011の背面1011bを照射される。第1の光学シート1012は、照明光L14を、液晶パネル1011の背面1011bに向ける機能を持つ。第2の光学シート1013は、照明光L14による細かな照明むらなどの光学的影響を抑制する機能を持つ。照明光L14は、面発光導光板1015の発光面1015aから出射された照明光である。
面光源装置1100の点灯時には、第1光源1018及び第2光源1101のそれぞれから光線が出射される。
以上に説明したように、実施の形態6の面光源装置1100は、第1光源1018と、第2光源1101と、拡散反射部材1102とを備えている。第1光源1018は、面発光導光板1015の光入射面(側面)1015cに対向する位置に配置されている。第2光源1101は、面発光導光板1015の光入射面1015cより背面1015b側の位置に配置されている。拡散反射部材1102は、第2光線L12を光入射面1015cに導く光路変更部材としての機能を有する。このように、実施の形態6の面光源装置1100によれば、光路変更部材としての拡散反射部材1102を用いて第2光線L12の進行方向を面発光導光板1015の光入射面1015cに向かう方向に変えている。そのため、面発光導光板の厚み方向に並ぶ2種類の光源を面発光導光板の光入射面に対向して配置させた従来の構成に比べ、面発光導光板1015の厚みを薄くすることができる。
実施の形態6の液晶表示装置3001は、第1光源1018に青緑色のLED素子を備える構成とし、第2光源1101に赤色のレーザ発光素子を備える構成とした。しかし、本発明は、これに限るものではない。例えば、異なる複数の光源を備える液晶表示装置において、少なくとも1種類の広い角度強度分布を有する光源と他の少なくとも1種類の狭い角度強度分布を有する光源とを備える場合に、本発明を適用可能である。
《7-1》実施の形態7の構成
図24は、実施の形態7の液晶表示装置3002(面光源装置1200を含む)の構成を概略的に示す断面図である。面光源装置1200は、面発光導光板1015、光反射シート1017、シリンドリカルミラー1202、第1光源1018、及び第2光源1201を有する。面光源装置1300は、面発光導光板1015、光反射シート1017、光反射部材1302、第1光源1018、及び第2光源1301を有する。面光源装置1400は、面発光導光板1015、光反射シート1017、光反射ミラー1402、第1光源1018、及び第2光源1401を有する。面光源装置1500は、面発光導光板1015、光反射シート1017、シリンドリカルミラー1502、光反射ミラー1503、第1光源1018、及び第2光源1501を有する。また、図25は、図24に示される面光源装置1200の光反射部材としてのシリンドリカルミラー1202の構成を概略的に示す斜視図である。図24及び図25において、図18に示される構成と同一又は対応する構成には、同じ符号を付す。実施の形態7の液晶表示装置3002及び面光源装置1200は、実施の形態6における第2光源1101及び拡散反射部材1102に代えて、第2光源1201及びシリンドリカルミラー1202を備えた点が、実施の形態6の液晶表示装置3001及び面光源装置1100と相違する。第2光源1201及びシリンドリカルミラー1202を変更した点以外の点については、実施の形態7の液晶表示装置3002及び面光源装置1200は、実施の形態6の液晶表示装置3001及び面光源装置1100と同じである。なお、第2光源1201は、第2光源1101に対して配置が異なっているが、光源自体は異なるところが無く、同じである。
面光源装置1200の点灯時には、第1光源1018及び第2光源1201のそれぞれから光線が出射される。
以上に説明したように、実施の形態7の面光源装置1200は、第1光源1018と、第2光源1201と、シリンドリカルミラー1202とを備えている。第1光源1018は、面発光導光板1015の光入射面(側面)1015cに対向する位置に配置されている。第2光源1201は、面発光導光板1015の光入射面1015cより背面1015b側の位置に配置されている。シリンドリカルミラー1202は、第2光線L22を光入射面1015cに導く光路変更部材としての機能を有する光反射部材である。このように、実施の形態7の面光源装置1200によれば、シリンドリカルミラー1202によって第2光線L22の進行方向を面発光導光板1015の光入射面1015cに向かう方向に変えている。このため、面発光導光板の厚み方向に並ぶ2種類の光源を面発光導光板の光入射面に対向して配置させた従来の構成に比べ、面発光導光板1015の厚みを薄くすることができる。
図26は、実施の形態7の液晶表示装置における面光源装置1300の光反射部材1302の他の例を概略的に示す断面図である。また、図27は、図26に示される面光源装置1300の光反射部材1302の構成を拡大して示す断面図である。図26及び図27において、図24に示される構成と同一又は対応する構成には、同じ符号を付す。図26及び図27に示される面光源装置1300は、図24に示される第2光源1201及びシリンドリカルミラー1202に代えて、第2光源1301及び断面波形状の光反射ミラー1302を備えた点が、図24に示される面光源装置1200と相違する。断面波形状とは、凸状部と凹状部とが交互に連続する形状である。つまり、光反射部材1302は、凸状部と凹状部とが交互に連続する光反射面を有する。第2光源1301及び光反射ミラー1302が異なる点以外の点については、図26及び図27に示される面光源装置1300は、図24に示される面光源装置1200と同じである。なお、第2光源1301は第2光源1201と異なる符号を付したが、光源自体は同じである。
図28は、実施の形態7の液晶表示装置における面光源装置1400の光反射部材を概略的に示す断面図である。図28において、図24に示される構成と同一又は対応する構成には、同じ符号を付す。図28に示される面光源装置1400は、図24に示される第2光源1201及びシリンドリカルミラー1202に代えて、第2光源1401及び断面多角形状の連続する光反射面を有する光反射ミラー1402を備えた点が、図24に示される面光源装置1200と相違する。断面多角形状とは、断面がシリンドリカルミラーのように曲面ではなく、複数の直線で構成される多角形の形状である。第2光源1401及び光反射ミラー1402が異なる点以外の点については、図28に示される面光源装置2400は、図24に示される面光源装置1200と同じである。なお、第2光源1401は符号が第2光源1201と異なるが、光源自体は同じである。図28において、L41は、第1光源1018からの第1光線であり、上記第1光線L11と同種の光線である。また、L42は第2光源1401からの第2光線であり、上記第1光線L12と同種の光線である。
図29は、実施の形態7の液晶表示装置における面光源装置1500の光反射部材を概略的に示す断面図である。図29において、図24に示される構成と同一又は対応する構成には、同じ符号を付す。図29に示される面光源装置1500は、第2光源1501及びシリンドリカルミラー1502に加えて、円筒状凸面の光反射面1503aを持つ光反射ミラー1503を有する点が、図24に示される面光源装置1200と相違する。シリンドリカルミラー1502は、円筒状凹面の光反射面1502aを持つ。光反射ミラー1503を有す点で異なる以外の点については、図29に示される面光源装置1500は、図24に示される面光源装置1200と同じである。なお、第2光源1501は、符号が第2光源1201と異なるが、光源自体は同じである。また、シリンドリカルミラー1502は、符号がシリンドリカルミラー1202と異なるが、曲面形状が異なる点以外は、シリンドリカルミラー1202と同じである。図29において、L51は、第1光源1018からの第1光線であり、上記第1光線L11と同種の光線である。また、L52は第2光源1501からの第2光線であり、上記第1光線L12と同種の光線である。また、シリンドリカルミラー1502は、図24におけるシリンドリカルミラーと同様の形状を持つ。
《8-1》実施の形態8の構成
図30は、実施の形態8の液晶表示装置3006(面光源装置1600を含む)の構成を概略的に示す断面図である。面光源装置1600は、面発光導光板1015、光反射シート1017、導光部材1610、シリンドリカルミラー1602、第1光源1018、第2光源1601を有する。面光源装置1700は、面発光導光板1015、光反射シート1017、導光部材1710、シリンドリカルミラー1702、第1光源1018、第2光源1601を有する。また、面光源装置1800は、面発光導光板1015、光反射シート1017、導光部材1810、シリンドリカルミラー1802、光反射ミラー1803、第1光源1018、第2光源1801を有する。また、図31は、図30に示される面光源装置(バックライトユニット)1600の面発光導光板1015の光入射面1015c近傍の構成を示す図である。図30及び図31において、図18に示される構成と同一又は対応する構成には、同じ符号を付す。実施の形態8の液晶表示装置3006及び面光源装置1600は、実施の形態6(又は7)における第2光源1101,1111(又は構成1201,1301,1401,1501)及び拡散反射部材1102,1112(又は構成1202,1302,1402,1502及び1503)に代えて、第2光源1601、光源用導光部材1610、及びシリンドリカルミラー1602を備えた点が、実施の形態6(又は7)の液晶表示装置3001,3011(又は3002)及び面光源装置1100,1112(又は、1200,1300,1400,1500)と相違する。拡散反射部材1102,1112は、光路変更部材としての機能を有する。シリンドリカルミラー1602は、光反射部材としての機能を有する。第2光源1601、光源用導光部材1610及びシリンドリカルミラー1602の異なる点以外の点については、実施の形態8の液晶表示装置3006及び面光源装置1600は、実施の形態6(又は7)の液晶表示装置3001(又は3002)及び面光源装置1100(又は、1200,1300,1400,1500)と同じである。なお、第2光源1601の符号は第2光源1101,1111と異なるが、光源としては同じである。
θt=sin-1(1.00/1.49)≒42.16°
となる。したがって、角度強度分布の半値全角が5°(半角は2.5°)である第2光線L62が傾斜端面1610bに入射する場合には、傾斜端面1610bに対する第2光線L62の入射角は、(θt+2.5)°を満たすように、44.7°以上とすることが望ましい。
第2光線L62の最適な光路を作るために、傾斜端面1610bのxy平面に対する傾斜角を変更してもよい。第2光線L62の最適な光路は、傾斜端面1610bに対する第2光線L62の入射角、また、光出射面1610c、シリンドリカルミラー1602、面発光導光板1015との位置関係や配置角度の関係により決まる。
面光源装置1600の点灯時には、第1光源1018及び第2光源1601のそれぞれから光線が出射される。
以上に説明したように、実施の形態8の面光源装置1600は、第1光源1018と、第2光源1601と、光源用導光部材1610及びシリンドリカルミラー1602を備えている。第1光源1018は、面発光導光板1015の光入射面(側面)1015cに対向する位置に配置されている。第2光源1601は、面発光導光板1015の光入射面1015cより背面1015b側の位置に配置されている。光源用導光部材1610は、第2光線L62を光入射面1015cに導く光路変更部材としての機能を有する。このように、実施の形態8の面光源装置1600によれば、光路変更部材によって第2光線L62の進行方向を面発光導光板1015の光入射面1015cに向かう方向に変えている。このため、面発光導光板の厚み方向に並ぶ2種類の光源を面発光導光板の光入射面に対向して配置させた従来の構成に比べ、面発光導光板1015の厚みを薄くすることができる。
図32は、実施の形態8の液晶表示装置3007(面光源装置1700を含む)の他の例の構成を概略的に示す断面図である。図32において、図30に示される構成と同一又は対応する構成には、同じ符号を付す。図32の液晶表示装置3007及び面光源装置1700は、光源用導光部材1710の形状及び配置が、図30の液晶表示装置3006及び面光源装置1600と相違する。配置の相違点は、光源用導光部材1710が面発光導光板1015に対して傾斜して配置されている点である。つまり、光源用導光部材1710は、xy平面に対して傾斜して配置されている。形状の相違点は、傾斜端面1710bの傾斜角度が異なる点である。光源用導光部材1710は、光路変更部材としての機能を有する。また、液晶表示装置3007及び面光源装置1700は、第2光源1701の配置が、図30の液晶表示装置3006及び面光源装置1600と相違する。図32におけるシリンドリカルミラー1702の光反射面1702aの形状は、図30のシリンドリカルミラー1602の光反射面1602aの形状と同様である。他の点については、図32に示される液晶表示装置3007及び面光源装置1700は、図30に示される液晶表示装置3006及び面光源装置1600と同じである。他の点とは、光源用導光部材1710の形状及び配置が異なる点以外の点であり、第2光源の配置が異なる点以外の点である。
図34は、実施の形態8の液晶表示装置3008(面光源装置1800を含む)の他の例の構成を概略的に示す断面図である。図34において、図30に示される構成と同一又は対応する構成には、同じ符号を付す。図34の液晶表示装置3008及び面光源装置1800は、次の点で図30の液晶表示装置3006及び面光源装置1600と相違する。第1の相違点は、光路変更部材としての光源用導光部材1810の形状である。第2の相違点は、光反射ミラー1803(凸状の第2の光反射面1803aを持つ。)を備える点である。第3の相違点は、シリンドリカルミラー1802(凹状の第1の光反射面1802aを持つ。)を備える点である。第2光源1801は、符号が異なるが、図30の液晶表示装置3006及び面光源装置1600と同じ光源である。シリンドリカルミラー1802の光反射面1802aの形状は、図30のシリンドリカルミラー1602の光反射面1602aの形状と同様である。他の点については、図34の液晶表示装置3008及び面光源装置1800は、図30の液晶表示装置3006及び面光源装置1600と同じである。
《9-1》実施の形態9の構成
図35は、実施の形態9の液晶表示装置3009(面光源装置1900を含む)の構成を概略的に示す断面図である。面光源装置1900は、面発光導光板1015、光反射シート1017、拡散反射部材1902、第1光源1018、第2光源1019を有する。面光源装置2000は、面発光導光板1015、光反射シート1017、光反射部材2002、第1光源1018、第2光源2001を有する。面光源装置2100は、面発光導光板1015、光反射シート1017、光反射部材2102、第1光源1018、第2光源2101を有する。面光源装置2200は、面発光導光板1015、光反射シート1017、光反射部材2202、第1光源1018、第2光源2201を有する。面光源装置2300は、面発光導光板1015、導光部材2311、シリンドリカルミラー2302、第1光源1018、第2光源2301を有する。面光源装置2400は、面発光導光板1015、導光部材2311、シリンドリカルミラー2402、第1光源1018、第2光源2401を有する。図35において、実施の形態6の図18に示される構成と同一又は対応する構成には、同じ符号を付し、詳細な説明を省略する。実施の形態9の液晶表示装置3009及び面光源装置1900は、第1光源1018の配置位置、第2光源1901の配置位置及び拡散反射部材1902の配置位置が、実施の形態6の液晶表示装置3001及び面光源装置1100と相違する。実施の形態6の液晶表示装置3001及び面光源装置1100は、各構成要素が、+z軸方向に第2光源1101、拡散反射部材1102及び第1光源1018の順に配置されている。一方、実施の形態9の液晶表示装置3009及び面光源装置1900は、各構成要素が、+z軸方向に第2光源1901、第1光源1018及び拡散反射部材1902の順に配置されている。上記の構成要素の配置の順番以外の点については、実施の形態9の液晶表示装置3009及び面光源装置1900は、実施の形態6の液晶表示装置3001及び面光源装置1100と同じである。
面光源装置1900の点灯時には、第1光源1018及び第2光源1901のそれぞれから光線が出射される。
以上に説明したように、実施の形態9の面光源装置1900は、第1光源1018、第2光源1901及び拡散反射部材1902を備えている。第1光源1018は、面発光導光板1015の光入射面(側面)1015cに対向する位置に配置されている。第2光源1901は、面発光導光板1015の光入射面1015cより背面1015b側の位置に配置されている。拡散反射部材1902は、第2光線L92を光入射面1015cに導く光路変更部材としての機能を有する。このように、実施の形態9の面光源装置1900は、拡散反射部材1902を用いて第2光線L12の進行方向を面発光導光板1015の光入射面1015cに向かう方向に変えている。拡散反射部材1102は、光路変更部材としての機能を有する。そのため、面発光導光板の厚み方向に並ぶ2種類の光源を面発光導光板の光入射面に対向して配置させた従来の構成に比べ、面発光導光板1015の厚みを薄くすることができる。
図36は、実施の形態9の液晶表示装置における面光源装置2000の光反射部材2002の他の例を概略的に示す断面図である。図36において、図35に示される構成と同一又は対応する構成には、同じ符号を付す。図36に示される面光源装置2000は、下記の点で図35に示される面光源装置1900と相違する。第1の相違点は、図35に示される第2光源1901に代えて第2光源2001を備える点である。第2の相違点は、拡散反射部材1902に代えて、シリンドリカルミラー2002を備えた点である。ただし、第2光源2001は、符号は異なるが、第2光源1901と同様である。上記2つの相違以外の点については、図36に示される面光源装置2000は、図35に示される面光源装置2900と同じである。図36において、第1光線L101は、第1光源1018から出射する光線である。第1光線L101は、上記第1光線L91と同種の光線である。また、第2光線L102は、第2光源2001から出射する光線である。第2光線L102は、上記第1光線L92と同種の光線である。さらに、シリンドリカルミラー2002は、実施の形態7におけるシリンドリカルミラー1202と同じ構成を有する。図36の例によっても、図35の場合と同様の効果を得ることができる。
図39は、実施の形態9の液晶表示装置3013(面光源装置2300を含む)の構成を概略的に示す断面図である。また、図40は、図39に示される面光源装置(バックライトユニット)2300の面発光導光板1015の光入射面1015c近傍の構成を示す図である。図39及び図40において、図30に示される構成と同一又は対応する構成には、同じ符号を付す。実施の形態9の液晶表示装置3013及び面光源装置2300は、+z軸方向における第1光源1018及びシリンドリカルミラー2302の配置の順番が、実施の形態8の液晶表示装置3006及び面光源装置1600と相違する。実施の形態8において、シリンドリカルミラー1602,1702,1802及び第1光源1018は、+z軸方向にシリンドリカルミラー1602,1702,1802、第1光源1018の順番に配置されている。なお、シリンドリカルミラー1602,1702,1802及び第1光源1018は、面発光導光板1015の光入射面1015cと対向する位置に配置されている。また、シリンドリカルミラー1602は、光反射部材としての機能を有する。実施の形態9において、シリンドリカルミラー2302及び第1光源1018は、+z軸方向に第1光源1018、シリンドリカルミラー2302の順番に配置されている。図39におけるシリンドリカルミラー2302の光反射面2302aの形状は、図30のシリンドリカルミラー1602の光反射面1602aの形状と同様である。上記の相違以外の点については、液晶表示装置3013及び面光源装置2300は、実施の形態8の液晶表示装置3006及び面光源装置1600と同じである。
実施の形態10に示す面光源装置2500は、ローカルディミング(Local Dimming)に対応した面光源装置である。ローカルディミングは、複数の発光素子を独立して制御する調光制御方法である。ローカルディミングにより、画面内の画像の黒い部分のエリアにおける光源を発光させず、画像の明るい部分のエリアにおける光源は発光させるという制御が可能になる。このような制御により、例えば、画面全体が暗い映像の場合であっても、その画面の中の特に暗い特定の場所のみについて、バックライトを暗く点灯させることによって、コントラスト比を高めることができる。
図46は、実施の形態11の液晶表示装置4001(面光源装置2600を含む)の構成の一例を概略的に示す断面図である。図46において、図42(実施の形態10)に示される構成要素と同一又は対応する構成要素には、同じ符号を付す。液晶表示装置4001は、透過型表示装置である。
Claims (20)
- 発光面、該発光面の反対側の背面、及び前記発光面の辺と前記背面の辺との間を繋ぐ複数の側面を有し、前記複数の側面のうちのいずれか1つの側面である光入射面から入射した光線を前記発光面から出射させる面発光導光板と、
前記光入射面に対向して配置され、前記光入射面に向けて第1光線を出射する第1光源と、
第2光線を出射する第2光源と、
前記第2光源から出射した前記第2光線を前記光入射面に導く光路変更部材と
を備え、
前記第1光線及び前記第2光線の両方は、前記光入射面から、前記面発光導光板に入射する
ことを特徴とする面光源装置。 - 前記光路変更部材は、前記光入射面に入射する直前における前記第2光線の角度強度分布を、前記光入射面に入射する直前における前記第1光線の角度強度分布に近付けるように、前記第2光線の進行方向を変える部材であるとともに角度強度分布を変える部材であることを特徴とする請求項1に記載の面光源装置。
- 前記面発光導光板は、
前記光入射面から入射された前記第1光線及び前記第2光線を混合する混合領域と、
前記混合領域を通過した光線を前記発光面から面状光として出射させる導光領域と
を有することを特徴とする請求項1又は2に記載の面光源装置。 - 前記光路変更部材は、前記第2光線の進行方向及び角度強度分布を変える第1の光反射面を持つ第1の光反射部材を有することを特徴とする請求項1から3までのいずれか1項に記載の面光源装置。
- 前記第1の光反射部材の前記第1の光反射面は、前記光入射面に対向し、入射した光を拡散させ反射する拡散光反射面を含むことを特徴とする請求項4に記載の面光源装置。
- 前記第1の光反射部材の前記第1の光反射面は、前記光入射面の長手方向に直交する面で切る断面形状が凹形状の部分及び凸形状の部分の少なくとも一方を含むことを特徴とする請求項4に記載の面光源装置。
- 前記光路変更部材は、前記第2光源から出射された前記第2光線を、前記第1の光反射部材の前記第1の光反射面に導く光源用導光部材をさらに有することを特徴とする請求項4から6までのいずれか1項に記載の面光源装置。
- 前記第1光源は、複数の第1発光素子を有し、
前記第2光源は、複数の第2発光素子を有する
ことを特徴とする請求項1から7までのいずれか1項に記載の面光源装置。 - 前記光源用導光部材は、隣接する第2発光素子から出射された第2光線同士が自ら有する発散角で広がり、前記光入射面において重なり合うために必要な所定の光学距離を有することを特徴とする請求項8に記載の面光源装置。
- 前記光源用導光部材は、前記第2発光素子の光軸に平行な面で分割された複数の導光素子を有することを特徴とする請求項8又は9に記載の面光源装置。
- 前記光路変更部材は、
前記面発光導光板と略平行な方向に延びる第1光路を形成する第1の導光部と
前記光入射面に対向し、前記面発光導光板の背面に略垂直な方向に延びる第2光路を形成する第2の導光部と
を含む導光部材を有し、
前記第2の光線は、前記第1の導光部から入射する
ことを特徴とする請求項1に記載の面光源装置。 - 前記導光部材は、前記第2光線の角度強度分布を変える拡散面又は反射面を有することを特徴とする請求項11に記載の面光源装置。
- 前記面光源装置は、光拡散素子をさらに有し、
前記光拡散素子は前記導光部材の出射面と前記面発光導光板の光入射面との間に配置されることを特徴とする請求項11又は12に記載の面光源装置。 - 前記面光源装置の光入射面は、光を拡散する光拡散部を有する請求項11から13までのいずれか1項に記載の面光源装置。
- 前記第1光源は、複数の第1発光素子を有し、
前記第2光源は、複数の第2発光素子を有する
ことを特徴とする請求項11から14までのいずれか1項に記載の面光源装置。 - 前記導光部材は、隣接する第2発光素子から出射された第2光線同士が自ら有する発散角で広がり、前記光入射面において重なり合うために必要な所定の光学距離を有することを特徴とする請求項15に記載の面光源装置。
- 前記導光部材は、前記第2発光素子の光軸に平行な面で分割された複数の導光素子を有することを特徴とする請求項15又は16に記載の面光源装置。
- 前記第1光源は、発光ダイオードを有し、前記第2光源は、レーザ発光素子を有することを特徴とする請求項1から17までのいずれか1項に記載の面光源装置。
- 前記レーザ発光素子は、赤色レーザ発光素子を含むことを特徴とする請求項18に記載の面光源装置。
- 液晶パネルと、
前記液晶パネルの背面に面状光を照射する、請求項1から19までのいずれか1項に記載の面光源装置と
を備えたことを特徴とする液晶表示装置。
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Also Published As
Publication number | Publication date |
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JP5367185B2 (ja) | 2013-12-11 |
WO2012098739A1 (ja) | 2012-07-26 |
US8998474B2 (en) | 2015-04-07 |
CN103328881A (zh) | 2013-09-25 |
US20130322114A1 (en) | 2013-12-05 |
KR20130094856A (ko) | 2013-08-26 |
TWI570478B (zh) | 2017-02-11 |
CN103328881B (zh) | 2016-08-24 |
JPWO2012099099A1 (ja) | 2014-06-30 |
TW201239471A (en) | 2012-10-01 |
KR101509368B1 (ko) | 2015-04-07 |
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