US20100110339A1 - Light emitting element and liquid crystal display device - Google Patents
Light emitting element and liquid crystal display device Download PDFInfo
- Publication number
- US20100110339A1 US20100110339A1 US12/530,323 US53032308A US2010110339A1 US 20100110339 A1 US20100110339 A1 US 20100110339A1 US 53032308 A US53032308 A US 53032308A US 2010110339 A1 US2010110339 A1 US 2010110339A1
- Authority
- US
- United States
- Prior art keywords
- light
- light emitting
- guide plate
- light sources
- light guide
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Images
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
- G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
- G02B6/0066—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form characterised by the light source being coupled to the light guide
- G02B6/0068—Arrangements of plural sources, e.g. multi-colour light sources
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
- G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
- G02B6/0033—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
-
- 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
- G02B6/0078—Side-by-side arrangements, e.g. for large area displays
- G02B6/008—Side-by-side arrangements, e.g. for large area displays of the partially overlapping type
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
- G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
- G02B6/0033—Means for improving the coupling-out of light from the light guide
- G02B6/0035—Means for improving the coupling-out of light from the light guide provided on the surface of the light guide or in the bulk of it
- G02B6/0045—Means for improving the coupling-out of light from the light guide provided on the surface of the light guide or in the bulk of it by shaping at least a portion of the light guide
- G02B6/0046—Tapered light guide, e.g. wedge-shaped light guide
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
- G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
- G02B6/0066—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
- G02B6/0073—Light emitting diode [LED]
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
- G02F1/1336—Illuminating devices
- G02F1/133602—Direct backlight
- G02F1/133609—Direct backlight including means for improving the color mixing, e.g. white
-
- 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
Definitions
- the present invention relates to a light emitting element including a light source unit provided with a plurality of light emitting diodes of two or more colors, the light emitting diodes being provided in a given order and a light guide plate for causing light from each of the plurality of light emitting diodes to surface-emit (emit in a form of plane emission), the light guide plate including a color mixing section for mixing colors of light from each of the plurality of light emitting diodes and, a display section for causing the light mixed by the color mixing section to surface-emit.
- an illumination device is provided on front or back side of a liquid crystal panel.
- a light source which is provided on back side is generally referred to as a backlight.
- backlights There are two types of backlights: (i) a direct backlight in which a light source is provided directly below a liquid crystal panel; and (ii) a backlight of edge light type in which a surface light source is obtained by providing a light source on an edge surface of a light guide plate for guiding light.
- a cold cathode fluorescent tube is generally used as the light source.
- an illumination device whose light source is a mercury-free light emitting diode has been developed in recent years under the influence of environmental issues and the like.
- a white illumination device is obtained by (i) using a white light emitting diode which is a combination of a blue light emitting diode and a yellow light emitting fluorescent substance or (ii) disposing a plurality of sets of monochromatic light emitting diodes each of which sets includes monochromatic light emitting diodes of respective different light emitting colors, such as red, green, and blue, so that colors of the respective monochromatic light emitting diodes are mixed.
- a backlight has attracted attention in recent years, in which backlight a combination of red, green, and blue monochromatic light emitting diodes, each capable of describing a broad range of color reproducibility, is employed.
- a liquid crystal television (LE-40M91B) is mass-produced in which red, green, and blue monochromatic light emitting diodes are used in combination in a direct backlight.
- a three-primary color light emitting diode set in which red, green, and blue light emitting diodes are used in combination, it is thus necessary to obtain white light by mixing colors of the light emitting diodes. Therefore, a uniform white backlight is obtained by providing a given gap between (i) a diffusing plate which is necessary to obtain uniform light and (ii) respective light emitting diodes.
- a backlight of edge light type in order to obtain a uniform white backlight in which red, green, and blue monochromatic light emitting diodes are used in combination, it is necessary for light emitting diodes of same color to be disposed at intervals of not less than 10 mm, on the grounds that (i) each light emitting diode is about 3 mm in width and (ii) a packaging interval should be secured. For this reason, it is necessary to devise a countermeasure in which light emitting colors are mixed.
- Lumileds Lighting, LLC has proposed an arrangement in which a color mixing section for mixing light emitting colors is not used as a display section (Non Patent Literature 1). In this way, in order to obtain a uniform white backlight in which red, green, and blue monochromatic light emitting diodes are used in combination, it is necessary to provide a color mixing section for mixing light emitting colors and a display section for providing illumination in white.
- a light guide plate includes a display section and a color mixing section having a distance of not less than a certain distance
- light which has been subjected to a color mixture by the color mixing section becomes white in the display section.
- the ratio of light emitted from a light emitting diode which is closest to the edge of the light guide plate becomes high on an edge surface of the light guide plate. Therefore, in a case where a color of the light emitting diode which is closest to the edge of the light guide plate is for example red, there occurs a problem that white light cannot be emitted through a discontinuous side end surface of the light guide plate but a slightly reddish light is emitted.
- the light emitting diode does not emit light with uniform luminance at any angle.
- Light emitted in a front direction is the strongest in luminance, and the luminance decreases as an angle to the front direction increases.
- a well color-mixed white light source is obtained in front of the R light emitting diode.
- the present invention has been made in view of the problems, and its object is to realize a light emitting element which allows obtaining of a well color-mixed white light source without being colored in a color of light emitted from a light emitting diode provided on a side end surface side of a light guide plate.
- a light emitting element includes: a plurality of light sources of two or more colors; and a light guide plate for causing light from the respective plurality of light sources to surface-emit, the plurality of light sources being provided along the light guide plate in a given order, the light guide plate including: a color mixing section for mixing colors of light from the respective plurality of light sources; and a display section for causing the light, which has been subjected to a color mixture by the color mixing section, to surface-emit, the plurality of light sources decreasing in their respective luminous intensities from a center toward ends of the light guide plate.
- the mixing section sufficiently to carry out a color mixture with respect to the colors, without being colored in a color of a light emitting diode provided to face the side end surface. This allows a realization of an uncolored white light source.
- the arrangement it is possible to reduce the influence of light reflected from a wall of a device even if a distance from the wall to a light source is closed. This causes suppression of being colored and it is thus possible to realize a liquid crystal display device whose frame is narrow. For this reason, it is possible to obtain a liquid crystal display device whose frame is narrow by use of such a light emitting element as a backlight of a liquid crystal display device.
- a light emitting element includes: a plurality of light sources of two or more colors; and a light guide plate for causing light from the respective plurality of light sources to surface-emit, the plurality of light sources being provided along one end part of the light guide plate in a given order, the light guide plate including: a color mixing section for mixing colors of light from the respective plurality of light sources; and a display section for causing the light, which has been subjected to a color mixture by the color mixing section, to surface-emit, the plurality of light sources being provided so that a central light source which is provided to face a center of one end part of the light guide plate is the highest in luminous intensity, and so that their luminous intensities decrease as they are away from the central light source.
- the light emitting element of the present invention includes a plurality of light sources emitting light in two or more kinds of colors and a light guide plate for causing light of each of the plurality of light sources to be diffused and surface-emitted.
- the plurality of light sources are provided along one end part of the light guide plate in a given order. According to the plurality of light sources thus provided, the light source which is provided to face the center of the plurality of light sources is the highest in luminous intensity and the other light sources decrease in luminous intensity as they are closer to the light sources which are provided to face the ends of the plurality of light sources.
- the mixing section sufficiently to carry out a color mixture with respect to the colors, without being colored in a color of a light emitting diode provided to face the side end surface. For this reason, it is possible to obtain a liquid crystal display device whose frame is narrow by use of such a light emitting element as a backlight of a liquid crystal display device.
- the light emitting element of the present invention may be arranged such that: each of the plurality of light sources is red, green, or blue light emitting diode; and the plurality of light sources are made up of a combination of the red, green, and blue light emitting diodes.
- this allows obtaining of a well color-mixed white light source in which the plurality of light emitting diodes of red (R), green (G), and blue (B) are provided so that their luminous intensities decrease from a light emitting diode provided to face the center of the light guide plate toward light sources provided to face respective ends of the light guide plate.
- the light emitting element of the present invention may further include luminous intensity adjustment means for adjusting a luminous intensity of each of the plurality of light sources by adjusting a current to be supplied to each of the plurality of light sources.
- the arrangement it is possible to realize a light emitting element which allows obtaining of a well color-mixed white light source without being colored in a color of light emitted from a light emitting diode provided on a discontinuous side end surface side of a light guide plate. Moreover, it is possible to reduce power consumption by decreasing a supplied current from a central light emitting diode which is provided to face a center of one end part of the light guide plate toward light emitting diodes which are provided away from the central light emitting diode.
- the light emitting element of the present invention may further include luminous intensity adjustment means for adjusting a luminous intensity of each of the plurality of light sources by adjusting a pulse width of a current to be supplied to each of the plurality of light sources.
- the arrangement it is possible to realize a light emitting element which allows obtaining of a well color-mixed white light source without being colored in a color of light emitted from a light emitting diode provided on a discontinuous side end surface side of a light guide plate. Moreover, it is possible to reduce power consumption by decreasing a pulse width of a supplied current from a central light emitting diode which is provided to face a center of one end part of the light guide plate toward light emitting diodes which are provided away from the central light emitting diode.
- the light emitting element of the present invention may also be arranged such that the plurality of light sources are provided along the light guide plate so that their luminous intensities decrease, in response to a supplied current, from a light source provided to face a center of the light guide plate toward light sources provided to face respective ends of the light guide plate.
- a driving circuit can be simply configured, thereby allowing a reduction in manufacturing costs.
- a liquid crystal display device includes: a liquid crystal panel; and a backlight for illuminating the liquid crystal panel, the backlight being arranged to include a light emitting element of the present invention.
- a liquid crystal display device of the present invention is capable of directing well color-mixed white light to a liquid crystal panel. This allows an improvement in display quality.
- FIG. 1 is a front elevational view illustrating how a light emitting element of the present embodiment is arranged.
- FIG. 2 is a plan view illustrating the arrangement of the light emitting element.
- FIG. 3 is a graph showing chromaticity “x” of a light guide plate which chromaticity “x” is obtained in a case where a luminous intensity of an LED is not decreased.
- FIG. 4 is a graph showing chromaticity “y” of a light guide plate which chromaticity “y” is obtained in a case where a luminous intensity of an LED is not decreased.
- FIG. 1 is a front elevational view illustrating how a light emitting element 1 of the present embodiment is arranged.
- FIG. 2 is a plan view of the light emitting element 1 .
- a liquid crystal display device 10 of the present embodiment includes a light emitting element 1 which serves as a backlight.
- the liquid crystal display device 10 includes a liquid crystal panel 11 and an illumination device 12 which is provided to face the liquid crystal panel 11 .
- the light emitting element 1 constituting this illumination device 12 is a light emitting element of the present invention. Light is irradiated from the illumination device 12 toward the liquid crystal panel 11 .
- the liquid crystal panel 11 is not particularly limited, and therefore a publicly-known liquid crystal panel is appropriately usable.
- the illumination device 12 includes a plurality of light guide plates 4 which are juxtaposed to each other.
- each of the plurality of light guide plates 4 includes a display section 6 having a light emitting surface and a color mixing section 5 for guiding light from corresponding light emitting diodes 3 (light source) to the display section 6 , and for mixing colors of light from the corresponding light emitting diodes 3 .
- the display section 6 and the color mixing section 5 are different from each other in thickness, at least at a part where the display section 6 and the color mixing section 5 are connected together.
- Adjacent light guide plates 4 are provided such that a color mixing section 5 of one of the adjacent light guide plates 4 is located under a display section 6 of the other of the adjacent light guide plates 4 . This causes light emitting surfaces of the plurality of light guide plates 4 to be provided so as to be flush with each other (a light emitting surface of the entire backlight 2 is provided).
- Such a structure of an illumination device is called a tandem structure.
- a reflecting sheet 14 is provided on a side of a surface of the light guide plate 4 which surface is opposite to a surface facing the liquid crystal panel 11 .
- An optical unit 2 is provided so as to face a light entrance section 6 a of each of the plurality of light guide plates 4 .
- the optical unit 2 includes a plurality of light emitting diodes 3 provided along the light entrance section 6 a .
- Each of the light emitting diodes 3 is mounted on a substrate 15 .
- Each of the plurality of light guide plates 4 includes a color mixing section 5 for mixing colors of light emitted from the respective light emitting diodes 3 and a display section 6 for causing the light which has been subjected to a color mixture by the color mixing section 5 to surface-emit.
- the display section 6 causes the incident light to surface-emit and to be directed to the liquid crystal panel 11 . Therefore, the display section 6 can also be referred to as an emission section.
- Drivers 7 for turning on respective light emitting diodes mounted on the substrate 15 are provided under the substrate 15 .
- the drivers 7 supply currents or the like to the respective light emitting diodes 3 so as to control turning on of the respective light emitting diodes 3 .
- the driver 7 can also be referred to as a light source controlling section.
- a chassis 9 is provided under the substrate 15 so as to contain these members.
- an optical sheet 13 is provided above the light guide plate 4 . The optical sheet 13 homogenizes and converges light emitted from the display section 6 of the light guide plate 4 , and then directs the light thus converged to the liquid crystal panel 11 . The following describes each of the constituents.
- the illumination device 12 includes the plurality of light guide plates 4 , which are not particularly limited.
- the plurality of light guide plates 4 do not need to have such a shape as illustrated in FIGS. 1 and 2 .
- the number of the plurality of light guide plates 4 is not limited to a specific one but can be determined in accordance with a size of an object to be illuminated (e.g., the size of the liquid crystal panel 11 ) or the like. In a case where the number of light guide plates 4 is two or more, it is preferable that the light guide plates 4 be provided to be juxtaposed to each other.
- an interval between the light guide plates 4 is not particularly limited, but it is preferable that adjacent light guide plates 4 are provided with no space therebetween.
- the optical sheet 13 is generally realized by a member such as (i) a diffusing plate for causing uniform light to be directed toward the liquid crystal panel 11 , (ii) a diffusing sheet for converging and scattering light, (iii) a lens sheet for converging light so as to increase luminance in a front direction, or (iv) a polarized light reflecting sheet for increasing luminance of a liquid crystal display device by reflecting one polarization component of light and transmitting the other polarization component.
- a diffusing plate for causing uniform light to be directed toward the liquid crystal panel 11
- a diffusing sheet for converging and scattering light
- a lens sheet for converging light so as to increase luminance in a front direction
- a polarized light reflecting sheet for increasing luminance of a liquid crystal display device by reflecting one polarization component of light and transmitting the other polarization component.
- the illumination device 12 is provided with the reflecting sheet 14 so as to reflect (i) part of light directed from the light guide plate 4 and (ii) light retroreflected from the optical sheet 13 . More specifically, the reflecting sheet 14 reflects (i) the part of light directed from the light guide plate 4 and (ii) the light retroreflected from the optical sheet 13 , and then the light thus reflected is directed, in a planer shape, toward the diffusing plate, the diffusing sheet, the lens sheet, or the polarized light reflecting sheet which constitutes the optical sheet 13 .
- the “planar shape” means a state in which the intensities of light are substantially identical to each other in a surface parallel with respect to the diffusing plate, the diffusing sheet, the lens sheet, or the polarized light reflecting sheet.
- the reflecting sheet 14 need not be identical to the light guide plate 4 in number. Namely, the reflecting sheet 14 can also be prepared by use of integral molding.
- the light emitting diodes 3 are mounted on the substrate 15 and provided along the light entrance section 6 a of the light guide plate 4 .
- red (R), green (G), and blue (B) LEDs are used as the respective light emitting diodes 3 .
- the LEDs are provided in the order of R 1 , G 11 , B 1 , G 12 , R 2 , G 21 , 132 , G 22 , . . . Rn, Gn 1 , Bn, and Gn 2 from a side surface 4 b side of the light guide plate 4 . Note that an alignment of R, G, B, and G constitute 1 group.
- the LEDs are provided, in the order of Rn, Gn 1 , Bn, and Gn 2 , so that the rightmost LED “Gn 2 ” is lower in luminous intensity than the other green LEDs.
- the R LEDs, G LEDs, and B LEDs increase in their respective luminous intensities from an end toward a center. That is, the R LEDs, G LEDs, and B LEDs increase in their luminous intensities from the leftmost end toward the center and decrease in their luminous intensities from the center toward the rightmost end.
- the LEDs be provided at a regular interval, but not limited to such a regular interval.
- the light emitting diodes 3 are provided so that the central light emitting diode 3 , provided to face the center of the light entrance section 6 a which is one end of the light guide plate 4 , is the highest in luminous intensity, and the other light emitting diodes 3 decrease in luminous intensity as they are away from the central light emitting diode 3 (that is, from center toward the end of the light entrance section 6 a ).
- a luminous intensity by a method of adjusting a current to be supplied to each of the LEDs from the driver 7 .
- Other methods of adjusting a luminous intensity include a method of reducing a pulse width of a current to be supplied to each of the LEDs from the driver 7 .
- the driver 7 serves as luminous intensity adjustment means, by controlling the driving of each of the LEDs.
- the following describes another method of setting a luminous intensity of each of the light emitting diodes 3 as mentioned above. Namely, in a case of selecting light emitting diodes to be provided in a line along the light entrance section 6 a of the light guide plate 4 , light emitting diodes ranked high in luminous intensity are selected as those provided to face the vicinity of the center of the light guide plate, whereas light emitting diodes ranked low in luminous intensity are selected as those provided to face the vicinity of end parts of the light guide plate.
- a light emitting diode ranked high in luminous intensity means a light emitting diode which has a higher light emitting luminous intensity in response to a supplied current, as compared with a light emitting diode ranked low in luminous intensity. That is, the rank of luminous intensity means a characteristic of a light emitting diode which characteristic is determined in accordance with high or low of a light emitting luminous intensity obtained when an identical current is supplied to the light emitting diode.
- the light emitting diodes 3 are provided along the light entrance section 6 a of the light guide plate 4 so that their luminous intensities decrease, in response to a supplied current, from the light emitting diode 3 provided to face the center of the light entrance section 6 a which is one end part of the light guide plate 4 toward the light emitting diodes 3 provided to face the ends of the light entrance section 6 a.
- the driver 7 can be simply configured, thereby allowing a reduction in manufacturing costs.
- the driver 7 is mounted on the substrate 15 on which the light emitting diode 3 is mounted. This causes a reduction in the number of substrates and a reduction in components such as connectors for connecting the substrates together. On this account, a cost reduction can be realized. Moreover, it is possible to further reduce the thickness of an illumination device because the number of the substrates is small.
- the light emitting diodes 3 be provided as close as possible to the light guide plate 4 . This allows an improvement in the efficiency in entering of light into the light guide plate 4 from the light emitting diodes 3 . This ultimately allows a realization of a highly-efficient light emitting element.
- the light guide plate 4 is made from a transparent resin such as PMMA (methyl methacrylate resin) or polycarbonate. It should be noted that the transparent resin is not limited to PMMA or polycarbonate, but any resin is applicable as long as it is transparent.
- a transparent resin such as PMMA (methyl methacrylate resin) or polycarbonate. It should be noted that the transparent resin is not limited to PMMA or polycarbonate, but any resin is applicable as long as it is transparent.
- the light guide plate 4 is prepared by a molding method such as injection molding, extrusion molding, press molding with heat, or cutting.
- a molding method such as injection molding, extrusion molding, press molding with heat, or cutting.
- the present embodiment is not limited to the methods. Any processing method can be employed as long as it brings about a characteristic similar to that of any of the methods.
- the LED “R 1 ” provided on the side surface 4 b side of the light guide plate 4 is lower in luminous intensity than the other LEDs. This causes suppression of being colored in red in the end part on the side surface 4 b side of the light guide plate 4 , thereby allowing a realization of a white light source whose colors are uniform at any position in a surface from which the white light outgoes.
- FIG. 3 is a graph showing chromaticity “x” of the cross section A-A′ in FIG. 2 which chromaticity “x” is obtained in a case where the LED “R 1 ” is not set to be lower in luminous intensity than the other LEDs.
- FIG. 4 is a graph showing chromaticity “y” of the cross section A-A′ in FIG. 2 which chromaticity “y” is obtained in a case where a luminous intensity of the LED “R 1 ” is not lowered.
- the horizontal axis shows positions, where the respective LEDs are provided, extending along the light entrance section 6 a of the light guide plate 4 .
- Scales of one (e.g., leftmost) end part, a center part, and the other (e.g., rightmost) end part of the light guide plate 4 are set to ‘0’, ‘100 ’, and ‘200 ’, respectively.
- the end part of the light guide plate 4 is colored in red since the chromaticity ‘x’ of the end part is large.
- each of the chromaticity “x” and “y” is constant regardless of the position. This allows a realization of a white illumination device whose colors are uniform.
- the LEDs decrease in luminous intensity from the center toward the end of the light guide plate with gradations such as R 1 ⁇ R 2 ⁇ R 3 . . . , G 11 ⁇ G 12 ⁇ G 21 ⁇ G 22 . . . , and B 1 ⁇ B 2 ⁇ B 3 . . . .
- scatterer is attached to the side surface 4 b of the end part of the light guide plate 4 .
- An adhesive or a white reflecting sheet exemplifies the scattering body.
- the scatterer causes the light which enters into the light guide plate 4 from the LED “R 1 ” to be scattered instead of being totally reflected from the side surface 4 b .
- This causes a reduction in light amount of the LED “R 1 ” in the end part of the light guide plate 4 .
- the scatterer is attached to the side surface 4 b , by causing the conditions for the total reflection not to be met with the use of (i) a method in which the side surface 4 b is subjected to micro-fabrication or (ii) a method in which the side surface 4 b is realized by an absorbing surface.
- the micro-fabrication is realized by (i) causing the side surface 4 b to be filed, (ii) causing the side surface 4 b to be subjected to sandblast, or (iii) causing the side surface 4 b to be subjected to process which is carried out to a prism or a lens.
- the absorbing surface is obtained by causing the side surface 4 b to be subjected to black printing or by causing black paper to be attached to the side surface 4 b.
- a scatterer is attached to front or back side of the color mixing section 5 in the end part of the light guide plate 4 .
- the scatterer scatters the light which enters into the light guide plate 4 from the LED “R 1 ”, thereby causing the conditions for total reflection not to be met. This causes a reduction in light amount of the LED “R 1 ” in the end part of the light guide plate. For this reason, it is possible to suppress the problem that the display section 6 in the end part of the light guide plate 4 is colored in red, thereby allowing a realization of a white illumination device whose colors are uniform.
- a light emitting element of the present invention may include: a light source unit provided with a plurality of light emitting diodes of two or more colors, the light emitting diodes being provided in a given order; and a light guide plate for causing light from the respective plurality of light emitting diodes to surface-emit, the light guide plate including: a color mixing section for mixing colors of light from the respective plurality of light emitting diodes; and a display section for causing the light, which has been subjected to a color mixture by the color mixing section, to surface-emit, the light emitting element being provided with luminous intensity adjustment means for adjusting a luminous intensity of each of the plurality of light emitting diodes so that luminous intensities of the plurality of light emitting diodes decrease from a light emitting diode provided to face a center of the light guide plate toward light emitting diodes provided to face respective ends of the light guide plate.
- a light emitting element which allows obtaining of a well color-mixed white light source without being colored in a color of light emitted from a light emitting diode provided on a discontinuous side end surface side of a light guide plate.
- a light emitting element allows obtaining of a liquid crystal display device whose frame is narrow.
- the light emitting element of the present invention is preferably arranged such that the light source unit is provided with red, green, and blue light emitting diodes.
- the light emitting element of the present invention is preferably arranged such that the luminous intensity adjustment means adjusts a luminous intensity of each of the plurality of light emitting diodes by adjusting a current to be supplied to each of the plurality of light emitting diodes.
- the arrangement it is possible to realize a light emitting element which allows obtaining of a well color-mixed white light source without being colored in a color of light emitted from a light emitting diode provided on a discontinuous side end surface side of a light guide plate. Moreover, it is possible to reduce power consumption by decreasing a supplied current from a central light emitting diode which is provided to face a center of the light guide plate toward light emitting diodes which are provided to face respective ends of the light guide plate.
- the light emitting element of the present invention is preferably arranged such that the luminous intensity adjustment means adjusts a luminous intensity of each of the plurality of light emitting diodes by adjusting a pulse width of a current to be supplied to each of the plurality of light emitting diodes.
- the arrangement it is possible to realize a light emitting element which allows obtaining of a well color-mixed white light source without being colored in a color of light emitted from a light emitting diode provided on a discontinuous side end surface side of a light guide plate. Moreover, it is possible to reduce power consumption by decreasing a pulse width of a supplied current from a central light emitting diode which is provided to face a center of the light guide plate toward light emitting diodes which are provided to face respective ends of the light guide plate.
- the light emitting element of the present invention is preferably arranged such that: the luminous intensity adjustment means is constituted by the plurality of light emitting diodes; and the plurality of light emitting diodes are provided so that their luminous intensities decrease, in response to a supplied current, from a light emitting diode provided to face a center of the light guide plate toward light emitting diodes provided to face respective ends of the light guide plate.
- light emitting diodes ranked high in luminous intensity are used as those provided to face the vicinity of the center of the light guide plate, whereas light emitting diodes ranked low in luminous intensity are used as those provided to face the vicinity of end parts of the light guide plate. This saves the need of selecting light emitting diodes and thus a cost reduction in light emitting diodes can be realized.
- a light emitting element of the present invention may include: a light source unit provided with a plurality of light emitting diodes of two or more colors, the light emitting diodes being provided in a given order; and a light guide plate for causing light from the respective plurality of light emitting diodes to surface-emit, the light guide plate including: a color mixing section for mixing colors of light from the respective plurality of light emitting diodes; and a display section for causing the light, which has been subjected to a color mixture by the color mixing section, to surface-emit, the light emitting element being provided with scatterer attached to a side surface of the light guide plate.
- the scatterer attached to the side surface of the light guide plate causes the light which enters into the light guide plate from a light emitting diode to be scattered instead of being totally reflected from the side surface in the end part of the light guide plate. This allows suppression of being colored in a color of light emitted from a light emitting diode provided at the end and it is thus possible to realize a white light source whose colors are uniform.
- a light emitting element of the present invention may include: a light source unit provided with a plurality of light emitting diodes of two or more colors, the light emitting diodes being provided in a given order; and a light guide plate for causing light from the respective plurality of light emitting diodes to surface-emit, the light guide plate including: a color mixing section for mixing colors of light from the respective plurality of light emitting diodes; and a display section for causing the light, which has been subjected to a color mixture by the color mixing section, to surface-emit, micro-fabrication being provided for a side surface of the light guide plate.
- the micro-fabricated side surface of the light guide plate causes the light which enters into the light guide plate from a light emitting diode to be scattered instead of being totally reflected from the side surface in the end part of the light guide plate. This allows suppression of being colored in a color of light emitted from a light emitting diode provided at the end and it is thus possible to realize a white light source whose colors are uniform.
- a light emitting element of the present invention may include: a light source unit provided with a plurality of light emitting diodes of two or more colors, the light emitting diodes being provided in a given order; and a light guide plate for causing light from the respective plurality of light emitting diodes to surface-emit, the light guide plate including: a color mixing section for mixing colors of light from the respective plurality of light emitting diodes; and a display section for causing the light, which has been subjected to a color mixture by the color mixing section, to surface-emit, the light emitting element being provided with scatterer attached to front or back side of the color mixing section in the end part of the light guide plate.
- the scatterer attached to front or back side of the color mixing section in the end part of the light guide plate causes the light which enters into the light guide plate from a light emitting diode to be scattered in the end part of the light guide plate and this causes a reduction in light amount of the light to be guided to the display section.
- This allows suppression of being colored in a color of light emitted from a light emitting diode provided at the end and it is thus possible to realize a white light source whose colors are uniform.
- a light emitting element of the present invention may include: a light source unit provided with a plurality of light emitting diodes of two or more colors, the light emitting diodes being provided in a given order; and a light guide plate for causing light from the respective plurality of light emitting diodes to surface-emit, the light guide plate including: a color mixing section for mixing colors of light from the respective plurality of light emitting diodes; and a display section for causing the light, which has been subjected to a color mixture by the color mixing section, to surface-emit, micro-fabrication being provided for front or back side of the color mixing section in the end part of the light guide plate.
- micro-fabricated front or back side of the color mixing section in the end part of the light guide plate causes the light which enters into the light guide plate from a light emitting diode to be scattered in the end part of the light guide plate and this causes a reduction in light amount of the light to be guided to the display section.
- This allows suppression of being colored in a color of light emitted from a light emitting diode provided at the end and it is thus possible to realize a white light source whose colors are uniform.
- a light emitting element of the present invention may include: a light source unit provided with a plurality of light emitting diodes of two or more colors, the light emitting diodes being provided in a given order; and a light guide plate for causing light from the respective plurality of light emitting diodes to surface-emit, the light guide plate including: a color mixing section for mixing colors of light from the respective plurality of light emitting diodes; and a display section for causing the light, which has been subjected to a color mixture by the color mixing section, to surface-emit, a side surface of the light guide plate serving as an absorbing surface.
- the absorbing side surface of the light guide plate causes the light which enters into the light guide plate from a light emitting diode to be absorbed on the side surface in the end part of the light guide plate. This allows suppression of being colored in a color of light emitted from a light emitting diode provided at the end and it is thus possible to realize a white light source whose colors are uniform.
- the present invention is applicable to a light emitting element including: a light source unit provided with a plurality of light emitting diodes of two or more colors, the light emitting diodes being provided in a given order; and a light guide plate for causing light from the respective plurality of light emitting diodes to surface-emit, the light guide plate including: a color mixing section for mixing colors of light from the respective plurality of light emitting diodes; and a display section for causing the light, which has been subjected to a color mixture by the color mixing section, to surface-emit.
- a light emitting element of the present invention is applicable to a backlight of a liquid crystal display device.
Abstract
A light emitting element (1) includes: a plurality of light emitting diodes [3 (R1, G11, . . . )] of two or more colors; and a light guide plate (4) for causing light from the respective plurality of light emitting diodes [3 (R1, G11, . . . )] to surface-emit. The light emitting diodes are provided along the light guide plate (4) in a given order. The light guide plate (4) includes: a color mixing section (5) for mixing colors of light from the respective plurality of light emitting diodes [3 (R1, G11, . . . )]; and a display section (6) for causing the light, which has been subjected to a color mixture by the color mixing section (5), to surface-emit. The plurality of light emitting diodes [3 (R1, G11, . . . )] decrease in their respective luminous intensities from a center toward ends of the light guide plate (4). This allows obtaining a well color-mixed white light source without being colored in a color of light emitted from a light emitting diode provided on a side end surface side of a light guide plate.
Description
- The present invention relates to a light emitting element including a light source unit provided with a plurality of light emitting diodes of two or more colors, the light emitting diodes being provided in a given order and a light guide plate for causing light from each of the plurality of light emitting diodes to surface-emit (emit in a form of plane emission), the light guide plate including a color mixing section for mixing colors of light from each of the plurality of light emitting diodes and, a display section for causing the light mixed by the color mixing section to surface-emit.
- In a liquid crystal display device, an illumination device is provided on front or back side of a liquid crystal panel. A light source which is provided on back side is generally referred to as a backlight. There are two types of backlights: (i) a direct backlight in which a light source is provided directly below a liquid crystal panel; and (ii) a backlight of edge light type in which a surface light source is obtained by providing a light source on an edge surface of a light guide plate for guiding light.
- For either type, a cold cathode fluorescent tube is generally used as the light source. On the other hand, an illumination device whose light source is a mercury-free light emitting diode has been developed in recent years under the influence of environmental issues and the like.
- In a case where a light emitting diode is used as the light source, a white illumination device is obtained by (i) using a white light emitting diode which is a combination of a blue light emitting diode and a yellow light emitting fluorescent substance or (ii) disposing a plurality of sets of monochromatic light emitting diodes each of which sets includes monochromatic light emitting diodes of respective different light emitting colors, such as red, green, and blue, so that colors of the respective monochromatic light emitting diodes are mixed. A backlight has attracted attention in recent years, in which backlight a combination of red, green, and blue monochromatic light emitting diodes, each capable of describing a broad range of color reproducibility, is employed.
- For example, a liquid crystal television (LE-40M91B) is mass-produced in which red, green, and blue monochromatic light emitting diodes are used in combination in a direct backlight. According to a three-primary color light emitting diode set in which red, green, and blue light emitting diodes are used in combination, it is thus necessary to obtain white light by mixing colors of the light emitting diodes. Therefore, a uniform white backlight is obtained by providing a given gap between (i) a diffusing plate which is necessary to obtain uniform light and (ii) respective light emitting diodes.
- In a backlight of edge light type, in order to obtain a uniform white backlight in which red, green, and blue monochromatic light emitting diodes are used in combination, it is necessary for light emitting diodes of same color to be disposed at intervals of not less than 10 mm, on the grounds that (i) each light emitting diode is about 3 mm in width and (ii) a packaging interval should be secured. For this reason, it is necessary to devise a countermeasure in which light emitting colors are mixed. Lumileds Lighting, LLC has proposed an arrangement in which a color mixing section for mixing light emitting colors is not used as a display section (Non Patent Literature 1). In this way, in order to obtain a uniform white backlight in which red, green, and blue monochromatic light emitting diodes are used in combination, it is necessary to provide a color mixing section for mixing light emitting colors and a display section for providing illumination in white.
-
Patent Literature 1 - Japanese Patent Application Publication, Tokukai, No. 2006-236951 A (Publication Date: Sep. 7, 2006)
-
Patent Literature 2 - Japanese Patent Application Publication, Tokukai, No. 2003-187622 A (Publication Date: Jul. 4, 2003)
-
Patent Literature 3 - Japanese Patent Application Publication, Tokukai, No. 2005-183124 A (Publication Date: Jul. 7, 2005)
-
Patent Literature 4 - Japanese Patent Application Publication, Tokukai, No. 2005-332681 A (Publication Date: Dec. 2, 2005)
-
Patent Literature 5 - Japanese Patent Application Publication, Tokukai, No. 2005-332680 A (Publication Date: Dec. 2, 2005)
-
Non Patent Literature 1 - the Mar. 31, 2003, issue of Nikkei Electronics No. 844, pp. 126-127
- As mentioned above, in an arrangement in which a light guide plate includes a display section and a color mixing section having a distance of not less than a certain distance, light which has been subjected to a color mixture by the color mixing section becomes white in the display section. However, the ratio of light emitted from a light emitting diode which is closest to the edge of the light guide plate becomes high on an edge surface of the light guide plate. Therefore, in a case where a color of the light emitting diode which is closest to the edge of the light guide plate is for example red, there occurs a problem that white light cannot be emitted through a discontinuous side end surface of the light guide plate but a slightly reddish light is emitted.
- As for an angular characteristic of emission luminance of a light emitting diode, the light emitting diode does not emit light with uniform luminance at any angle. Light emitted in a front direction is the strongest in luminance, and the luminance decreases as an angle to the front direction increases. For example, in a case where light emitting diodes of three primary colors of R, G, and B are used, a well color-mixed white light source is obtained in front of the R light emitting diode. Specifically, (i) light obliquely emitted from G and B light emitting diodes which are neighbors on the right of the R light emitting diode and (ii) light obliquely emitted from G and B light emitting diodes which are neighbors on the left of the R light emitting diode are guided to a display section in front of the R light emitting diode. Then, R, 0, and B light are mixed with each other, so that a white light source can be obtained. For example, on a right edge surface of a light guide plate, colors of light emitted obliquely to the right from each light emitting diode provided on the left side are mixed. However, since there is no light emitting diode provided on the right side, light amounts of respective colors other than a color of light emitted from the rightmost light emitting diode is small. Unfortunately, light emitted to the right from the rightmost light emitting diode is totally reflected from the right edge surface. As such, a light amount of the rightmost light emitting diode becomes large. This has caused a problem that a side end surface of a light guide plate is colored in a color of light emitted from a light emitting diode which is closest to the edge of the light guide plate.
- The present invention has been made in view of the problems, and its object is to realize a light emitting element which allows obtaining of a well color-mixed white light source without being colored in a color of light emitted from a light emitting diode provided on a side end surface side of a light guide plate.
- In order to solve the aforementioned problems, a light emitting element according to the present invention includes: a plurality of light sources of two or more colors; and a light guide plate for causing light from the respective plurality of light sources to surface-emit, the plurality of light sources being provided along the light guide plate in a given order, the light guide plate including: a color mixing section for mixing colors of light from the respective plurality of light sources; and a display section for causing the light, which has been subjected to a color mixture by the color mixing section, to surface-emit, the plurality of light sources decreasing in their respective luminous intensities from a center toward ends of the light guide plate.
- According to the arrangement, it is possible, on a discontinuous side end surface of the light guide plate, for the mixing section sufficiently to carry out a color mixture with respect to the colors, without being colored in a color of a light emitting diode provided to face the side end surface. This allows a realization of an uncolored white light source.
- Furthermore, according to the arrangement, it is possible to reduce the influence of light reflected from a wall of a device even if a distance from the wall to a light source is closed. This causes suppression of being colored and it is thus possible to realize a liquid crystal display device whose frame is narrow. For this reason, it is possible to obtain a liquid crystal display device whose frame is narrow by use of such a light emitting element as a backlight of a liquid crystal display device.
- A light emitting element according to the present invention includes: a plurality of light sources of two or more colors; and a light guide plate for causing light from the respective plurality of light sources to surface-emit, the plurality of light sources being provided along one end part of the light guide plate in a given order, the light guide plate including: a color mixing section for mixing colors of light from the respective plurality of light sources; and a display section for causing the light, which has been subjected to a color mixture by the color mixing section, to surface-emit, the plurality of light sources being provided so that a central light source which is provided to face a center of one end part of the light guide plate is the highest in luminous intensity, and so that their luminous intensities decrease as they are away from the central light source.
- The light emitting element of the present invention includes a plurality of light sources emitting light in two or more kinds of colors and a light guide plate for causing light of each of the plurality of light sources to be diffused and surface-emitted. In this light emitting element, the plurality of light sources are provided along one end part of the light guide plate in a given order. According to the plurality of light sources thus provided, the light source which is provided to face the center of the plurality of light sources is the highest in luminous intensity and the other light sources decrease in luminous intensity as they are closer to the light sources which are provided to face the ends of the plurality of light sources.
- According to the arrangement, it is possible, on a discontinuous side end surface of the light guide plate, for the mixing section sufficiently to carry out a color mixture with respect to the colors, without being colored in a color of a light emitting diode provided to face the side end surface. For this reason, it is possible to obtain a liquid crystal display device whose frame is narrow by use of such a light emitting element as a backlight of a liquid crystal display device.
- The light emitting element of the present invention may be arranged such that: each of the plurality of light sources is red, green, or blue light emitting diode; and the plurality of light sources are made up of a combination of the red, green, and blue light emitting diodes.
- According to the arrangement, it is possible to realize a light emitting element including a light source capable of describing a broad range of color reproducibility.
- Moreover, this allows obtaining of a well color-mixed white light source in which the plurality of light emitting diodes of red (R), green (G), and blue (B) are provided so that their luminous intensities decrease from a light emitting diode provided to face the center of the light guide plate toward light sources provided to face respective ends of the light guide plate.
- The light emitting element of the present invention may further include luminous intensity adjustment means for adjusting a luminous intensity of each of the plurality of light sources by adjusting a current to be supplied to each of the plurality of light sources.
- According to the arrangement, it is possible to realize a light emitting element which allows obtaining of a well color-mixed white light source without being colored in a color of light emitted from a light emitting diode provided on a discontinuous side end surface side of a light guide plate. Moreover, it is possible to reduce power consumption by decreasing a supplied current from a central light emitting diode which is provided to face a center of one end part of the light guide plate toward light emitting diodes which are provided away from the central light emitting diode.
- The light emitting element of the present invention may further include luminous intensity adjustment means for adjusting a luminous intensity of each of the plurality of light sources by adjusting a pulse width of a current to be supplied to each of the plurality of light sources.
- According to the arrangement, it is possible to realize a light emitting element which allows obtaining of a well color-mixed white light source without being colored in a color of light emitted from a light emitting diode provided on a discontinuous side end surface side of a light guide plate. Moreover, it is possible to reduce power consumption by decreasing a pulse width of a supplied current from a central light emitting diode which is provided to face a center of one end part of the light guide plate toward light emitting diodes which are provided away from the central light emitting diode.
- The light emitting element of the present invention may also be arranged such that the plurality of light sources are provided along the light guide plate so that their luminous intensities decrease, in response to a supplied current, from a light source provided to face a center of the light guide plate toward light sources provided to face respective ends of the light guide plate.
- According to the arrangement, it is possible to use light sources which are different in luminous intensity level when supplied with a certain current and it is thus unnecessary to change a current to be supplied from a driving circuit or the like to each of the plurality of light sources Accordingly, a driving circuit can be simply configured, thereby allowing a reduction in manufacturing costs.
- A liquid crystal display device according to the present invention includes: a liquid crystal panel; and a backlight for illuminating the liquid crystal panel, the backlight being arranged to include a light emitting element of the present invention.
- Provided with a light emitting element of the present invention as a backlight, a liquid crystal display device of the present invention is capable of directing well color-mixed white light to a liquid crystal panel. This allows an improvement in display quality.
- For a fuller understanding of the nature and advantages of the invention, reference should be made to the ensuing detailed description taken in conjunction with the accompanying drawings.
-
FIG. 1 is a front elevational view illustrating how a light emitting element of the present embodiment is arranged. -
FIG. 2 is a plan view illustrating the arrangement of the light emitting element. -
FIG. 3 is a graph showing chromaticity “x” of a light guide plate which chromaticity “x” is obtained in a case where a luminous intensity of an LED is not decreased. -
FIG. 4 is a graph showing chromaticity “y” of a light guide plate which chromaticity “y” is obtained in a case where a luminous intensity of an LED is not decreased. -
-
- 1 Light emitting element
- 2 Optical unit
- 3 Light emitting diode
- 4 Light guide plate
- 4 b Side surface
- 5 Color mixing section
- 6 Display section
- 7 Driver (Luminous intensity adjustment means)
- 9 Chassis
- 10 Liquid crystal display device
- 11 Liquid crystal panel
- 12 Illumination device
- 13 Optical sheet
- 14 Reflecting sheet
- 15 Substrate
- An embodiment of the present invention is described below with reference to
FIGS. 1 to 4 .FIG. 1 is a front elevational view illustrating how alight emitting element 1 of the present embodiment is arranged.FIG. 2 is a plan view of thelight emitting element 1. - A liquid
crystal display device 10 of the present embodiment includes alight emitting element 1 which serves as a backlight. For example, as illustrated inFIG. 1 , the liquidcrystal display device 10 includes a liquid crystal panel 11 and anillumination device 12 which is provided to face the liquid crystal panel 11. Thelight emitting element 1 constituting thisillumination device 12 is a light emitting element of the present invention. Light is irradiated from theillumination device 12 toward the liquid crystal panel 11. The liquid crystal panel 11 is not particularly limited, and therefore a publicly-known liquid crystal panel is appropriately usable. - The following describes the
illumination device 12 of the present embodiment. For example, as illustrated inFIG. 1 , theillumination device 12 includes a plurality oflight guide plates 4 which are juxtaposed to each other. Specifically, each of the plurality oflight guide plates 4 includes adisplay section 6 having a light emitting surface and acolor mixing section 5 for guiding light from corresponding light emitting diodes 3 (light source) to thedisplay section 6, and for mixing colors of light from the correspondinglight emitting diodes 3. Thedisplay section 6 and thecolor mixing section 5 are different from each other in thickness, at least at a part where thedisplay section 6 and thecolor mixing section 5 are connected together. Adjacentlight guide plates 4 are provided such that acolor mixing section 5 of one of the adjacentlight guide plates 4 is located under adisplay section 6 of the other of the adjacentlight guide plates 4. This causes light emitting surfaces of the plurality oflight guide plates 4 to be provided so as to be flush with each other (a light emitting surface of theentire backlight 2 is provided). Such a structure of an illumination device is called a tandem structure. A reflectingsheet 14 is provided on a side of a surface of thelight guide plate 4 which surface is opposite to a surface facing the liquid crystal panel 11. - An
optical unit 2 is provided so as to face alight entrance section 6 a of each of the plurality oflight guide plates 4. Theoptical unit 2 includes a plurality oflight emitting diodes 3 provided along thelight entrance section 6 a. Each of thelight emitting diodes 3 is mounted on asubstrate 15. Each of the plurality oflight guide plates 4 includes acolor mixing section 5 for mixing colors of light emitted from the respectivelight emitting diodes 3 and adisplay section 6 for causing the light which has been subjected to a color mixture by thecolor mixing section 5 to surface-emit. Thedisplay section 6 causes the incident light to surface-emit and to be directed to the liquid crystal panel 11. Therefore, thedisplay section 6 can also be referred to as an emission section. - Drivers 7 (luminous intensity adjustment means) for turning on respective light emitting diodes mounted on the
substrate 15 are provided under thesubstrate 15. The drivers 7 supply currents or the like to the respectivelight emitting diodes 3 so as to control turning on of the respectivelight emitting diodes 3. Accordingly, the driver 7 can also be referred to as a light source controlling section. Achassis 9 is provided under thesubstrate 15 so as to contain these members. Moreover, anoptical sheet 13 is provided above thelight guide plate 4. Theoptical sheet 13 homogenizes and converges light emitted from thedisplay section 6 of thelight guide plate 4, and then directs the light thus converged to the liquid crystal panel 11. The following describes each of the constituents. - As mentioned above, the
illumination device 12 includes the plurality oflight guide plates 4, which are not particularly limited. For example, it is possible to use a publicly-known light guide plate as alight guide plate 4. Moreover, the plurality oflight guide plates 4 do not need to have such a shape as illustrated inFIGS. 1 and 2 . Further, the number of the plurality oflight guide plates 4 is not limited to a specific one but can be determined in accordance with a size of an object to be illuminated (e.g., the size of the liquid crystal panel 11) or the like. In a case where the number oflight guide plates 4 is two or more, it is preferable that thelight guide plates 4 be provided to be juxtaposed to each other. Furthermore, an interval between thelight guide plates 4 is not particularly limited, but it is preferable that adjacentlight guide plates 4 are provided with no space therebetween. With the arrangement, light which is superior in uniformity of luminance can be directed toward the liquid crystal panel 11 since thelight guide plates 4 are uniformly distributed, with no space therebetween, in theillumination device 12. - The following describes the
optical sheet 13. Theoptical sheet 13 is generally realized by a member such as (i) a diffusing plate for causing uniform light to be directed toward the liquid crystal panel 11, (ii) a diffusing sheet for converging and scattering light, (iii) a lens sheet for converging light so as to increase luminance in a front direction, or (iv) a polarized light reflecting sheet for increasing luminance of a liquid crystal display device by reflecting one polarization component of light and transmitting the other polarization component. These members are appropriately used in combination in accordance with price and performance of a liquid crystal display device. - The
illumination device 12 is provided with the reflectingsheet 14 so as to reflect (i) part of light directed from thelight guide plate 4 and (ii) light retroreflected from theoptical sheet 13. More specifically, the reflectingsheet 14 reflects (i) the part of light directed from thelight guide plate 4 and (ii) the light retroreflected from theoptical sheet 13, and then the light thus reflected is directed, in a planer shape, toward the diffusing plate, the diffusing sheet, the lens sheet, or the polarized light reflecting sheet which constitutes theoptical sheet 13. Note that the “planar shape” means a state in which the intensities of light are substantially identical to each other in a surface parallel with respect to the diffusing plate, the diffusing sheet, the lens sheet, or the polarized light reflecting sheet. It should be noted that, though a plurality oflight guide plates 4 are provided with their respective reflectingsheets 14 inFIG. 1 , the reflectingsheet 14 need not be identical to thelight guide plate 4 in number. Namely, the reflectingsheet 14 can also be prepared by use of integral molding. - The
light emitting diodes 3 are mounted on thesubstrate 15 and provided along thelight entrance section 6 a of thelight guide plate 4. Here, red (R), green (G), and blue (B) LEDs are used as the respectivelight emitting diodes 3. As illustrated inFIG. 2 , the LEDs are provided in the order of R1, G11, B1, G12, R2, G21, 132, G22, . . . Rn, Gn1, Bn, and Gn2 from aside surface 4 b side of thelight guide plate 4. Note that an alignment of R, G, B, and G constitute 1 group. At a right end part of thelight guide plate 4, the LEDs are provided, in the order of Rn, Gn1, Bn, and Gn2, so that the rightmost LED “Gn2” is lower in luminous intensity than the other green LEDs. The R LEDs, G LEDs, and B LEDs increase in their respective luminous intensities from an end toward a center. That is, the R LEDs, G LEDs, and B LEDs increase in their luminous intensities from the leftmost end toward the center and decrease in their luminous intensities from the center toward the rightmost end. - It should be noted that how to combine LEDs and how to provide the LEDs are not limited to these. Furthermore, it is preferable that the LEDs be provided at a regular interval, but not limited to such a regular interval.
- For example, as for how to align R, G, and B LEDs, other than the alignment in the order of “R, G, B, and G” which constitute 1 group, an alignment in the order of “G, R, B, and G” which constitute 1 group (see paragraph [0250] of Patent Literature 5) is also adoptable. It is possible to further improve a color mixture, by adopting such an alignment of R, G, and B LEDs.
- As mentioned above, according to the present embodiment, the
light emitting diodes 3 are provided so that the centrallight emitting diode 3, provided to face the center of thelight entrance section 6 a which is one end of thelight guide plate 4, is the highest in luminous intensity, and the otherlight emitting diodes 3 decrease in luminous intensity as they are away from the central light emitting diode 3 (that is, from center toward the end of thelight entrance section 6 a). - In this case, it is possible to adjust a luminous intensity by a method of adjusting a current to be supplied to each of the LEDs from the driver 7. Other methods of adjusting a luminous intensity include a method of reducing a pulse width of a current to be supplied to each of the LEDs from the driver 7. In this way, the driver 7 serves as luminous intensity adjustment means, by controlling the driving of each of the LEDs.
- Further, the following describes another method of setting a luminous intensity of each of the
light emitting diodes 3 as mentioned above. Namely, in a case of selecting light emitting diodes to be provided in a line along thelight entrance section 6 a of thelight guide plate 4, light emitting diodes ranked high in luminous intensity are selected as those provided to face the vicinity of the center of the light guide plate, whereas light emitting diodes ranked low in luminous intensity are selected as those provided to face the vicinity of end parts of the light guide plate. It should be noted that a light emitting diode ranked high in luminous intensity means a light emitting diode which has a higher light emitting luminous intensity in response to a supplied current, as compared with a light emitting diode ranked low in luminous intensity. That is, the rank of luminous intensity means a characteristic of a light emitting diode which characteristic is determined in accordance with high or low of a light emitting luminous intensity obtained when an identical current is supplied to the light emitting diode. - That is, according to the arrangement, the
light emitting diodes 3 are provided along thelight entrance section 6 a of thelight guide plate 4 so that their luminous intensities decrease, in response to a supplied current, from thelight emitting diode 3 provided to face the center of thelight entrance section 6 a which is one end part of thelight guide plate 4 toward thelight emitting diodes 3 provided to face the ends of thelight entrance section 6 a. - With the arrangement, it is possible to set the luminous intensity of each of the
light emitting diodes 3 to a target value, instead of changing a current to be supplied from the driver 7 to each of thelight emitting diodes 3. For this reason, the driver 7 can be simply configured, thereby allowing a reduction in manufacturing costs. - The driver 7 is mounted on the
substrate 15 on which thelight emitting diode 3 is mounted. This causes a reduction in the number of substrates and a reduction in components such as connectors for connecting the substrates together. On this account, a cost reduction can be realized. Moreover, it is possible to further reduce the thickness of an illumination device because the number of the substrates is small. - It is preferable that the
light emitting diodes 3 be provided as close as possible to thelight guide plate 4. This allows an improvement in the efficiency in entering of light into thelight guide plate 4 from thelight emitting diodes 3. This ultimately allows a realization of a highly-efficient light emitting element. - The
light guide plate 4 is made from a transparent resin such as PMMA (methyl methacrylate resin) or polycarbonate. It should be noted that the transparent resin is not limited to PMMA or polycarbonate, but any resin is applicable as long as it is transparent. - The
light guide plate 4 is prepared by a molding method such as injection molding, extrusion molding, press molding with heat, or cutting. However, the present embodiment is not limited to the methods. Any processing method can be employed as long as it brings about a characteristic similar to that of any of the methods. - According to the
light emitting diodes 3 of the present embodiment, the LED “R1” provided on theside surface 4 b side of thelight guide plate 4 is lower in luminous intensity than the other LEDs. This causes suppression of being colored in red in the end part on theside surface 4 b side of thelight guide plate 4, thereby allowing a realization of a white light source whose colors are uniform at any position in a surface from which the white light outgoes. In this case, it is possible to reduce a luminous intensity of the LED “R1”, by (i) making a current to be supplied to the LED “R1” from the driver 7 lower than currents to be supplied to the other LEDs, (ii) making a pulse width of the current to be supplied to the LED “R1” narrower than pulse widths of the currents to be supplied to the other LEDs, or (iii) selecting and using, as the LED “R1”, an LED ranked low in luminous intensity. -
FIG. 3 is a graph showing chromaticity “x” of the cross section A-A′ inFIG. 2 which chromaticity “x” is obtained in a case where the LED “R1” is not set to be lower in luminous intensity than the other LEDs.FIG. 4 is a graph showing chromaticity “y” of the cross section A-A′ inFIG. 2 which chromaticity “y” is obtained in a case where a luminous intensity of the LED “R1” is not lowered. InFIGS. 3 and 4 , the horizontal axis shows positions, where the respective LEDs are provided, extending along thelight entrance section 6 a of thelight guide plate 4. Scales of one (e.g., leftmost) end part, a center part, and the other (e.g., rightmost) end part of thelight guide plate 4 are set to ‘0’, ‘100 ’, and ‘200 ’, respectively. - As illustrated in these drawings, the end part of the
light guide plate 4 is colored in red since the chromaticity ‘x’ of the end part is large. However, according to the present embodiment, it is possible that each of the chromaticity “x” and “y” is constant regardless of the position. This allows a realization of a white illumination device whose colors are uniform. - The description has dealt with an example of making the LED “R1” provided at the end lower in luminous intensity than the other LEDs. However, the present invention is not limited to this.
- For example, it is also possible to provide an arrangement in which the LEDs decrease in luminous intensity from the center toward the end of the light guide plate with gradations such as R1<R2<R3 . . . , G11<G12<G21<G22 . . . , and B1<B2<B3 . . . .
- In another embodiment of the present invention, scatterer is attached to the
side surface 4 b of the end part of thelight guide plate 4. An adhesive or a white reflecting sheet exemplifies the scattering body. The scatterer causes the light which enters into thelight guide plate 4 from the LED “R1” to be scattered instead of being totally reflected from theside surface 4 b. This causes a reduction in light amount of the LED “R1” in the end part of thelight guide plate 4. For this reason, it is possible to suppress the problem that thedisplay section 6 in the end part of thelight guide plate 4 is colored in red, thereby allowing a realization of a white illumination device whose colors are uniform. It is also possible to achieve the effect similar to the arrangement in which the scatterer is attached to theside surface 4 b, by causing the conditions for the total reflection not to be met with the use of (i) a method in which theside surface 4 b is subjected to micro-fabrication or (ii) a method in which theside surface 4 b is realized by an absorbing surface. The micro-fabrication is realized by (i) causing theside surface 4 b to be filed, (ii) causing theside surface 4 b to be subjected to sandblast, or (iii) causing theside surface 4 b to be subjected to process which is carried out to a prism or a lens. The absorbing surface is obtained by causing theside surface 4 b to be subjected to black printing or by causing black paper to be attached to theside surface 4 b. - In a further embodiment of the present invention, a scatterer is attached to front or back side of the
color mixing section 5 in the end part of thelight guide plate 4. The scatterer scatters the light which enters into thelight guide plate 4 from the LED “R1”, thereby causing the conditions for total reflection not to be met. This causes a reduction in light amount of the LED “R1” in the end part of the light guide plate. For this reason, it is possible to suppress the problem that thedisplay section 6 in the end part of thelight guide plate 4 is colored in red, thereby allowing a realization of a white illumination device whose colors are uniform. It is also possible to achieve the effect similar to the arrangement in which the scatterer is attached to front or back side of thecolor mixing section 5 in the end part of thelight guide plate 4, by causing the conditions for the total reflection not to be met with the use of a method in which theside surface 4 b is subjected to micro-fabrication. - The invention is not limited to the description of the embodiments above, but may be altered within the scope of the claims. An embodiment based on a proper combination of technical means disclosed in different embodiments is encompassed in the technical scope of the invention.
- A light emitting element of the present invention may include: a light source unit provided with a plurality of light emitting diodes of two or more colors, the light emitting diodes being provided in a given order; and a light guide plate for causing light from the respective plurality of light emitting diodes to surface-emit, the light guide plate including: a color mixing section for mixing colors of light from the respective plurality of light emitting diodes; and a display section for causing the light, which has been subjected to a color mixture by the color mixing section, to surface-emit, the light emitting element being provided with luminous intensity adjustment means for adjusting a luminous intensity of each of the plurality of light emitting diodes so that luminous intensities of the plurality of light emitting diodes decrease from a light emitting diode provided to face a center of the light guide plate toward light emitting diodes provided to face respective ends of the light guide plate.
- According to the arrangement, it is possible to realize a light emitting element which allows obtaining of a well color-mixed white light source without being colored in a color of light emitted from a light emitting diode provided on a discontinuous side end surface side of a light guide plate. Such a light emitting element allows obtaining of a liquid crystal display device whose frame is narrow.
- The light emitting element of the present invention is preferably arranged such that the light source unit is provided with red, green, and blue light emitting diodes.
- According to the arrangement, it is possible to realize a light emitting element including a light source capable of describing a broad range of color reproducibility.
- The light emitting element of the present invention is preferably arranged such that the luminous intensity adjustment means adjusts a luminous intensity of each of the plurality of light emitting diodes by adjusting a current to be supplied to each of the plurality of light emitting diodes.
- According to the arrangement, it is possible to realize a light emitting element which allows obtaining of a well color-mixed white light source without being colored in a color of light emitted from a light emitting diode provided on a discontinuous side end surface side of a light guide plate. Moreover, it is possible to reduce power consumption by decreasing a supplied current from a central light emitting diode which is provided to face a center of the light guide plate toward light emitting diodes which are provided to face respective ends of the light guide plate.
- The light emitting element of the present invention is preferably arranged such that the luminous intensity adjustment means adjusts a luminous intensity of each of the plurality of light emitting diodes by adjusting a pulse width of a current to be supplied to each of the plurality of light emitting diodes.
- According to the arrangement, it is possible to realize a light emitting element which allows obtaining of a well color-mixed white light source without being colored in a color of light emitted from a light emitting diode provided on a discontinuous side end surface side of a light guide plate. Moreover, it is possible to reduce power consumption by decreasing a pulse width of a supplied current from a central light emitting diode which is provided to face a center of the light guide plate toward light emitting diodes which are provided to face respective ends of the light guide plate.
- The light emitting element of the present invention is preferably arranged such that: the luminous intensity adjustment means is constituted by the plurality of light emitting diodes; and the plurality of light emitting diodes are provided so that their luminous intensities decrease, in response to a supplied current, from a light emitting diode provided to face a center of the light guide plate toward light emitting diodes provided to face respective ends of the light guide plate.
- According to the arrangement, light emitting diodes ranked high in luminous intensity are used as those provided to face the vicinity of the center of the light guide plate, whereas light emitting diodes ranked low in luminous intensity are used as those provided to face the vicinity of end parts of the light guide plate. This saves the need of selecting light emitting diodes and thus a cost reduction in light emitting diodes can be realized.
- A light emitting element of the present invention may include: a light source unit provided with a plurality of light emitting diodes of two or more colors, the light emitting diodes being provided in a given order; and a light guide plate for causing light from the respective plurality of light emitting diodes to surface-emit, the light guide plate including: a color mixing section for mixing colors of light from the respective plurality of light emitting diodes; and a display section for causing the light, which has been subjected to a color mixture by the color mixing section, to surface-emit, the light emitting element being provided with scatterer attached to a side surface of the light guide plate.
- According to the arrangement, the scatterer attached to the side surface of the light guide plate causes the light which enters into the light guide plate from a light emitting diode to be scattered instead of being totally reflected from the side surface in the end part of the light guide plate. This allows suppression of being colored in a color of light emitted from a light emitting diode provided at the end and it is thus possible to realize a white light source whose colors are uniform.
- A light emitting element of the present invention may include: a light source unit provided with a plurality of light emitting diodes of two or more colors, the light emitting diodes being provided in a given order; and a light guide plate for causing light from the respective plurality of light emitting diodes to surface-emit, the light guide plate including: a color mixing section for mixing colors of light from the respective plurality of light emitting diodes; and a display section for causing the light, which has been subjected to a color mixture by the color mixing section, to surface-emit, micro-fabrication being provided for a side surface of the light guide plate.
- According to the arrangement, the micro-fabricated side surface of the light guide plate causes the light which enters into the light guide plate from a light emitting diode to be scattered instead of being totally reflected from the side surface in the end part of the light guide plate. This allows suppression of being colored in a color of light emitted from a light emitting diode provided at the end and it is thus possible to realize a white light source whose colors are uniform.
- A light emitting element of the present invention may include: a light source unit provided with a plurality of light emitting diodes of two or more colors, the light emitting diodes being provided in a given order; and a light guide plate for causing light from the respective plurality of light emitting diodes to surface-emit, the light guide plate including: a color mixing section for mixing colors of light from the respective plurality of light emitting diodes; and a display section for causing the light, which has been subjected to a color mixture by the color mixing section, to surface-emit, the light emitting element being provided with scatterer attached to front or back side of the color mixing section in the end part of the light guide plate.
- According to the arrangement, the scatterer attached to front or back side of the color mixing section in the end part of the light guide plate causes the light which enters into the light guide plate from a light emitting diode to be scattered in the end part of the light guide plate and this causes a reduction in light amount of the light to be guided to the display section. This allows suppression of being colored in a color of light emitted from a light emitting diode provided at the end and it is thus possible to realize a white light source whose colors are uniform.
- A light emitting element of the present invention may include: a light source unit provided with a plurality of light emitting diodes of two or more colors, the light emitting diodes being provided in a given order; and a light guide plate for causing light from the respective plurality of light emitting diodes to surface-emit, the light guide plate including: a color mixing section for mixing colors of light from the respective plurality of light emitting diodes; and a display section for causing the light, which has been subjected to a color mixture by the color mixing section, to surface-emit, micro-fabrication being provided for front or back side of the color mixing section in the end part of the light guide plate.
- According to the arrangement, micro-fabricated front or back side of the color mixing section in the end part of the light guide plate causes the light which enters into the light guide plate from a light emitting diode to be scattered in the end part of the light guide plate and this causes a reduction in light amount of the light to be guided to the display section. This allows suppression of being colored in a color of light emitted from a light emitting diode provided at the end and it is thus possible to realize a white light source whose colors are uniform.
- A light emitting element of the present invention may include: a light source unit provided with a plurality of light emitting diodes of two or more colors, the light emitting diodes being provided in a given order; and a light guide plate for causing light from the respective plurality of light emitting diodes to surface-emit, the light guide plate including: a color mixing section for mixing colors of light from the respective plurality of light emitting diodes; and a display section for causing the light, which has been subjected to a color mixture by the color mixing section, to surface-emit, a side surface of the light guide plate serving as an absorbing surface.
- According to the arrangement, the absorbing side surface of the light guide plate causes the light which enters into the light guide plate from a light emitting diode to be absorbed on the side surface in the end part of the light guide plate. This allows suppression of being colored in a color of light emitted from a light emitting diode provided at the end and it is thus possible to realize a white light source whose colors are uniform.
- The embodiments discussed in the foregoing description of embodiments and concrete examples serve solely to illustrate the technical details of the present invention, which should not be narrowly interpreted within the limits of such embodiments and concrete examples, but rather may be applied in many variations within the spirit of the present invention, provided such variations do not exceed the scope of the patent claims set forth below.
- The present invention is applicable to a light emitting element including: a light source unit provided with a plurality of light emitting diodes of two or more colors, the light emitting diodes being provided in a given order; and a light guide plate for causing light from the respective plurality of light emitting diodes to surface-emit, the light guide plate including: a color mixing section for mixing colors of light from the respective plurality of light emitting diodes; and a display section for causing the light, which has been subjected to a color mixture by the color mixing section, to surface-emit. Furthermore, a light emitting element of the present invention is applicable to a backlight of a liquid crystal display device.
Claims (15)
1.-7. (canceled)
8. A light emitting element comprising:
a plurality of light sources made up of a combination of light emitting diodes; and
a light guide plate for causing light from the respective plurality of light sources to surface-emit, the plurality of light sources being provided along the light guide plate in a given order,
the light guide plate including:
a color mixing section for mixing colors of light from the respective plurality of light sources; and
a display section for causing the light, which has been subjected to a color mixture by the color mixing section, to surface-emit,
the plurality of light sources decreasing in their respective luminous intensities from a center toward ends of the light guide plate.
9. A light emitting element comprising:
a plurality of light sources made up of a combination of light emitting diodes; and
a light guide plate for causing light from the respective plurality of light sources to surface-emit, the plurality of light sources being provided along one end part of the light guide plate in a given order,
the light guide plate including:
a color mixing section for mixing colors of light from the respective plurality of light sources; and
a display section for causing the light, which has been subjected to a color mixture by the color mixing section, to surface-emit,
the plurality of light sources being provided so that a central light source which is provided to face a center of one end part of the light guide plate is the highest in luminous intensity, and so that their luminous intensities decrease as they are away from the central light source.
10. The light emitting element as set forth in claim 8 , wherein the plurality of light sources are made up of a combination of light sources of different colors.
11. The light emitting element as set forth in claim 8 , wherein:
each of the plurality of light sources is red, green, or blue light emitting diode; and
the plurality of light sources are made up of a combination of the red, green, and blue light emitting diodes.
12. The light emitting element as set forth in claim 8 , further comprising luminous intensity adjustment means for adjusting a luminous intensity of each of the plurality of light sources by adjusting a current to be supplied to each of the plurality of light sources.
13. The light emitting element as set forth in claim 8 , further comprising luminous intensity adjustment means for adjusting a luminous intensity of each of the plurality of light sources by adjusting a pulse width of a current to be supplied to each of the plurality of light sources.
14. The light emitting element as set forth in claim 8 , wherein
the plurality of light sources are provided along the light guide plate so that their luminous intensities decrease, in response to a supplied current, from a light source provided to face a center of the light guide plate toward light sources provided to face respective ends of the light guide plate.
15. A liquid crystal display device comprising:
a liquid crystal panel; and
a backlight for illuminating the liquid crystal panel,
the backlight being arranged to include a light emitting element as set forth in claim 8 .
16. The light emitting element as set forth in claim 9 , wherein the plurality of light sources are made up of a combination of light sources of different colors.
17. The light emitting element as set forth in claim 9 , wherein:
each of the plurality of light sources is red, green, or blue light emitting diode; and
the plurality of light sources are made up of a combination of the red, green, and blue light emitting diodes.
18. The light emitting element as set forth in claim 9 , further comprising luminous intensity adjustment means for adjusting a luminous intensity of each of the plurality of light sources by adjusting a current to be supplied to each of the plurality of light sources.
19. The light emitting element as set forth in claim 9 , further comprising luminous intensity adjustment means for adjusting a luminous intensity of each of the plurality of light sources by adjusting a pulse width of a current to be supplied to each of the plurality of light sources.
20. The light emitting element as set forth in claim 9 , wherein
the plurality of light sources are provided along the light guide plate so that their luminous intensities decrease, in response to a supplied current, from a light source provided to face a center of the light guide plate toward light sources provided to face respective ends of the light guide plate.
21. A liquid crystal display device comprising:
a liquid crystal panel; and
a backlight for illuminating the liquid crystal panel,
the backlight being arranged to include a light emitting element as set forth in claim 9 .
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2007117770 | 2007-04-26 | ||
JP2007-117770 | 2007-04-26 | ||
PCT/JP2008/057949 WO2008136359A1 (en) | 2007-04-26 | 2008-04-24 | Light emitting element and liquid crystal display device |
Publications (1)
Publication Number | Publication Date |
---|---|
US20100110339A1 true US20100110339A1 (en) | 2010-05-06 |
Family
ID=39943460
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US12/530,323 Abandoned US20100110339A1 (en) | 2007-04-26 | 2008-04-24 | Light emitting element and liquid crystal display device |
US12/521,813 Expired - Fee Related US8154689B2 (en) | 2007-04-26 | 2008-04-24 | Light emitting element and liquid crystal display apparatus |
Family Applications After (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US12/521,813 Expired - Fee Related US8154689B2 (en) | 2007-04-26 | 2008-04-24 | Light emitting element and liquid crystal display apparatus |
Country Status (6)
Country | Link |
---|---|
US (2) | US20100110339A1 (en) |
EP (2) | EP2172698A1 (en) |
JP (2) | JP5085645B2 (en) |
CN (2) | CN101578480A (en) |
BR (1) | BRPI0806882A2 (en) |
WO (2) | WO2008136359A1 (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20090122230A1 (en) * | 2007-11-14 | 2009-05-14 | Sony Corporation | Plane light source apparatus and liquid crystal display apparatus |
US20100059767A1 (en) * | 2008-09-10 | 2010-03-11 | Harison Toshiba Lighting Corporation | Surface Light-Emitting Device and Display Device Using the Same |
US20100315446A1 (en) * | 2009-06-15 | 2010-12-16 | An Byunghyun | Display device |
US20110050743A1 (en) * | 2009-08-27 | 2011-03-03 | Sangtae Park | Display device |
Families Citing this family (23)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP2172698A1 (en) | 2007-04-26 | 2010-04-07 | Sharp Kabushiki Kaisha | Light emitting element and liquid crystal display device |
JP5179908B2 (en) * | 2008-03-12 | 2013-04-10 | スタンレー電気株式会社 | Surface light source lighting device |
JP2010157455A (en) * | 2008-12-29 | 2010-07-15 | Funai Electric Co Ltd | Backlight for liquid crystal display |
JP2010177086A (en) * | 2009-01-30 | 2010-08-12 | Hitachi Ltd | Backlight unit and image display device using the same |
JP4742153B2 (en) * | 2009-01-30 | 2011-08-10 | キヤノン株式会社 | Document reader |
ITTV20090058A1 (en) * | 2009-03-26 | 2010-09-27 | Giovine Vincenzo Di | LED LAMINAR LIGHTING SYSTEM WITH INDUCED SCATTERING EFFECT |
KR101565409B1 (en) * | 2009-06-02 | 2015-11-03 | 엘지전자 주식회사 | LED back-light unit |
CN102004355A (en) * | 2009-08-31 | 2011-04-06 | 日立民用电子株式会社 | Liquid crystal display device |
JP2011053238A (en) * | 2009-08-31 | 2011-03-17 | Hitachi Consumer Electronics Co Ltd | Liquid crystal display apparatus and back light apparatus |
US20110051036A1 (en) * | 2009-08-31 | 2011-03-03 | Hitachi Consumer Electronics Co., Ltd. | Liquid Crystal Display Device |
US8446547B2 (en) * | 2009-12-03 | 2013-05-21 | Lg Display Co., Ltd. | Liquid crystal display device including back light unit having LED array |
JP5460435B2 (en) * | 2010-04-09 | 2014-04-02 | 日立コンシューマエレクトロニクス株式会社 | Image display device and control method of image display device |
CN101956935A (en) | 2010-07-30 | 2011-01-26 | 深圳市华星光电技术有限公司 | Backlight module and liquid crystal display device |
CN101994954A (en) * | 2010-07-30 | 2011-03-30 | 深圳市华星光电技术有限公司 | Back light module |
KR101706578B1 (en) * | 2010-10-08 | 2017-02-16 | 엘지디스플레이 주식회사 | backlight unit and liquid crystal display module including the same |
US8632236B2 (en) * | 2011-11-04 | 2014-01-21 | GE Lighting Solutions, LLC | LED lighting module and lighting device comprised thereof |
JP5952557B2 (en) * | 2011-12-26 | 2016-07-13 | 株式会社小糸製作所 | Light emitting module and vehicle lamp |
US9310034B2 (en) * | 2012-01-25 | 2016-04-12 | Koninklijke Philips N.V. | Light emitting device for backlight device and method of operating the light emitting device |
CN102661572A (en) * | 2012-04-18 | 2012-09-12 | 深圳市华星光电技术有限公司 | Light guide plate with upper prisms and backlight module corresponding to light guide plate |
JP5952086B2 (en) * | 2012-05-24 | 2016-07-13 | スタンレー電気株式会社 | Vehicle lighting |
US10908348B2 (en) * | 2015-09-24 | 2021-02-02 | Sharp Kabushiki Kaisha | Lighting device, display device, and television device |
KR102463846B1 (en) * | 2015-12-30 | 2022-11-04 | 엘지디스플레이 주식회사 | Backlight Unit and Display Apparatus having the same |
CN105629577B (en) * | 2016-03-31 | 2019-10-01 | 上海天马微电子有限公司 | Back light unit, display screen and display device |
Citations (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20050259441A1 (en) * | 2004-05-19 | 2005-11-24 | Takeo Arai | Backlight apparatus and liquid crystal display apparatus |
US20050259193A1 (en) * | 2004-05-24 | 2005-11-24 | Nec Corporation | Light source, display device, portable terminal device, and ray direction switching element |
US20060220040A1 (en) * | 2005-02-28 | 2006-10-05 | Toshihiro Suzuki | Surface illuminator and liquid crystal display having the same |
US20060221638A1 (en) * | 2005-04-01 | 2006-10-05 | Chew Tong F | Light-emitting apparatus having a plurality of adjacent, overlapping light-guide plates |
US20070014110A1 (en) * | 2005-07-12 | 2007-01-18 | Nec Lcd Technologies, Ltd. | Lighting unit and liquid crystal display device using the lighting unit |
US20070058108A1 (en) * | 2005-09-14 | 2007-03-15 | Nec Corporation Nec Lcd Technologies, Ltd | Light source device, display device, terminal device, light source unit, and method for driving light source device |
US20070115687A1 (en) * | 2005-11-24 | 2007-05-24 | Tpo Hong Kong Holding Limited | Light-emitting unit and method of producing the same |
US20080049445A1 (en) * | 2006-08-25 | 2008-02-28 | Philips Lumileds Lighting Company, Llc | Backlight Using High-Powered Corner LED |
US20080170178A1 (en) * | 2004-05-19 | 2008-07-17 | Shigeo Kubota | Lighting Device, and Liquid Crystal Display Device Using Same |
Family Cites Families (17)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH10334717A (en) * | 1997-05-29 | 1998-12-18 | Mitsubishi Electric Corp | Plane lighting system and heat-retaining lamp case used for the plane lighting system |
JP2003141921A (en) * | 2001-11-07 | 2003-05-16 | Seiko Epson Corp | Lighting device, electro-optic unit and electronic equipment, as well as manufacturing method of lighting device |
JP2003177249A (en) * | 2001-12-13 | 2003-06-27 | Nissha Printing Co Ltd | Light guide plate for front light device and method for manufacturing the same |
JP2003187622A (en) | 2001-12-18 | 2003-07-04 | Sharp Corp | Lighting device and display device |
JP2005183124A (en) | 2003-12-18 | 2005-07-07 | Matsushita Electric Ind Co Ltd | Planar light source and liquid crystal display device |
JP2005285704A (en) * | 2004-03-31 | 2005-10-13 | Citizen Watch Co Ltd | Translucent member and lighting system using it |
CN100483204C (en) | 2004-04-17 | 2009-04-29 | 鸿富锦精密工业(深圳)有限公司 | Light guide plate and back light module |
JP4628043B2 (en) * | 2004-08-26 | 2011-02-09 | オプトレックス株式会社 | Liquid crystal display device |
JP2006269364A (en) | 2005-03-25 | 2006-10-05 | Mitsubishi Rayon Co Ltd | Led surface light source device |
JP4848654B2 (en) * | 2005-03-25 | 2011-12-28 | 船井電機株式会社 | Liquid crystal display |
JP4430571B2 (en) * | 2005-03-25 | 2010-03-10 | 三菱レイヨン株式会社 | LED surface light source device |
JP4430585B2 (en) * | 2005-06-16 | 2010-03-10 | 三菱レイヨン株式会社 | Surface light source device |
WO2007020966A1 (en) * | 2005-08-17 | 2007-02-22 | Fujifilm Corporation | Planar illuminating device |
JP4778279B2 (en) * | 2005-09-02 | 2011-09-21 | 三菱レイヨン株式会社 | Optical mixing element and surface light source device using the same |
JP2007095635A (en) * | 2005-09-30 | 2007-04-12 | Yamaguchi Univ | Method and apparatus for performing light control of lighting apparatus in indication display |
JP4622787B2 (en) * | 2005-09-30 | 2011-02-02 | 日立ライティング株式会社 | Backlight system and liquid crystal display device |
EP2172698A1 (en) | 2007-04-26 | 2010-04-07 | Sharp Kabushiki Kaisha | Light emitting element and liquid crystal display device |
-
2008
- 2008-04-24 EP EP08752048A patent/EP2172698A1/en not_active Withdrawn
- 2008-04-24 BR BRPI0806882-8A patent/BRPI0806882A2/en not_active IP Right Cessation
- 2008-04-24 WO PCT/JP2008/057949 patent/WO2008136359A1/en active Application Filing
- 2008-04-24 EP EP08752027A patent/EP2149745A1/en not_active Withdrawn
- 2008-04-24 CN CNA200880001557XA patent/CN101578480A/en active Pending
- 2008-04-24 US US12/530,323 patent/US20100110339A1/en not_active Abandoned
- 2008-04-24 CN CN200880007100A patent/CN101622494A/en active Pending
- 2008-04-24 US US12/521,813 patent/US8154689B2/en not_active Expired - Fee Related
- 2008-04-24 JP JP2009512956A patent/JP5085645B2/en not_active Expired - Fee Related
- 2008-04-24 JP JP2009512951A patent/JPWO2008136349A1/en active Pending
- 2008-04-24 WO PCT/JP2008/057928 patent/WO2008136349A1/en active Application Filing
Patent Citations (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20050259441A1 (en) * | 2004-05-19 | 2005-11-24 | Takeo Arai | Backlight apparatus and liquid crystal display apparatus |
US20080170178A1 (en) * | 2004-05-19 | 2008-07-17 | Shigeo Kubota | Lighting Device, and Liquid Crystal Display Device Using Same |
US20050259193A1 (en) * | 2004-05-24 | 2005-11-24 | Nec Corporation | Light source, display device, portable terminal device, and ray direction switching element |
US20060220040A1 (en) * | 2005-02-28 | 2006-10-05 | Toshihiro Suzuki | Surface illuminator and liquid crystal display having the same |
US20060221638A1 (en) * | 2005-04-01 | 2006-10-05 | Chew Tong F | Light-emitting apparatus having a plurality of adjacent, overlapping light-guide plates |
US7311431B2 (en) * | 2005-04-01 | 2007-12-25 | Avago Technologies Ecbu Ip Pte Ltd | Light-emitting apparatus having a plurality of adjacent, overlapping light-guide plates |
US20070014110A1 (en) * | 2005-07-12 | 2007-01-18 | Nec Lcd Technologies, Ltd. | Lighting unit and liquid crystal display device using the lighting unit |
US20070058108A1 (en) * | 2005-09-14 | 2007-03-15 | Nec Corporation Nec Lcd Technologies, Ltd | Light source device, display device, terminal device, light source unit, and method for driving light source device |
US20070115687A1 (en) * | 2005-11-24 | 2007-05-24 | Tpo Hong Kong Holding Limited | Light-emitting unit and method of producing the same |
US20080049445A1 (en) * | 2006-08-25 | 2008-02-28 | Philips Lumileds Lighting Company, Llc | Backlight Using High-Powered Corner LED |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20090122230A1 (en) * | 2007-11-14 | 2009-05-14 | Sony Corporation | Plane light source apparatus and liquid crystal display apparatus |
US7973881B2 (en) * | 2007-11-14 | 2011-07-05 | Sony Corporation | Plane light source apparatus and liquid crystal display apparatus |
US20100059767A1 (en) * | 2008-09-10 | 2010-03-11 | Harison Toshiba Lighting Corporation | Surface Light-Emitting Device and Display Device Using the Same |
US20100315446A1 (en) * | 2009-06-15 | 2010-12-16 | An Byunghyun | Display device |
US8350800B2 (en) * | 2009-06-15 | 2013-01-08 | Lg Electronics Inc. | Display device |
US20110050743A1 (en) * | 2009-08-27 | 2011-03-03 | Sangtae Park | Display device |
US8330708B2 (en) * | 2009-08-27 | 2012-12-11 | Lg Electronics Inc. | Display device |
Also Published As
Publication number | Publication date |
---|---|
JP5085645B2 (en) | 2012-11-28 |
JPWO2008136359A1 (en) | 2010-07-29 |
BRPI0806882A2 (en) | 2015-06-16 |
CN101622494A (en) | 2010-01-06 |
US8154689B2 (en) | 2012-04-10 |
US20100103346A1 (en) | 2010-04-29 |
JPWO2008136349A1 (en) | 2010-07-29 |
EP2149745A1 (en) | 2010-02-03 |
WO2008136359A1 (en) | 2008-11-13 |
WO2008136349A1 (en) | 2008-11-13 |
CN101578480A (en) | 2009-11-11 |
EP2172698A1 (en) | 2010-04-07 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US20100110339A1 (en) | Light emitting element and liquid crystal display device | |
EP2151623B1 (en) | Lighting device, display device, and light guide plate | |
US8430519B2 (en) | Lighting device, display device and television receiver | |
US7690831B2 (en) | Surface light source device | |
US8459857B2 (en) | Planar light source device and display apparatus using the same | |
US8414173B2 (en) | Illumination device and display device | |
US20110025730A1 (en) | Illumination device, display device, and light guide plate | |
GB2425392A (en) | Light-emitting apparatus | |
US7512310B2 (en) | Backlight unit of a liquid crystal display device | |
US20120249885A1 (en) | Lighting device, display device and television receiver | |
KR101584280B1 (en) | Light guide plate and display apparatus having the same | |
EP2461205A2 (en) | Backlight device and image display using the same | |
JP2005222814A (en) | Surface light source device and display device using the same | |
US8950926B2 (en) | Planar light source apparatus and display apparatus using the same | |
US20110141396A1 (en) | Illumination device and liquid crystal display device | |
KR101754228B1 (en) | Liquid crystal display device | |
KR101822509B1 (en) | Liquid crystal display device | |
US20080291694A1 (en) | Planar light source device and display device | |
US20110116008A1 (en) | Illumination device and liquid crystal display device | |
KR20100095812A (en) | Back light unit and liquid crystal display comprising the same | |
WO2010004797A1 (en) | Illuminating device and liquid crystal display device | |
CN101963313A (en) | One-dimensional edge light dynamic backlight for liquid crystal display | |
JP4628043B2 (en) | Liquid crystal display device | |
KR101921166B1 (en) | Liquid crystal display device | |
KR101756670B1 (en) | Backlight unit and liquid crystal display device using the same |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: SHARP KABUSHIKI KAISHA,JAPAN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:AJICHI, YUHSAKU;MASUDA, TAKESHI;REEL/FRAME:023202/0215 Effective date: 20090806 |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |