JP2007141799A - Surface lighting light source, luminance correction circuit and luminance correction method used for surface lighting light source - Google Patents

Surface lighting light source, luminance correction circuit and luminance correction method used for surface lighting light source Download PDF

Info

Publication number
JP2007141799A
JP2007141799A JP2005337871A JP2005337871A JP2007141799A JP 2007141799 A JP2007141799 A JP 2007141799A JP 2005337871 A JP2005337871 A JP 2005337871A JP 2005337871 A JP2005337871 A JP 2005337871A JP 2007141799 A JP2007141799 A JP 2007141799A
Authority
JP
Japan
Prior art keywords
luminance
led
light emitting
emitting elements
correction circuit
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.)
Withdrawn
Application number
JP2005337871A
Other languages
Japanese (ja)
Inventor
Yuji Kondo
祐司 近藤
Nobuaki Honpo
信明 本保
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Tianma Japan Ltd
Original Assignee
NEC LCD Technologies Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by NEC LCD Technologies Ltd filed Critical NEC LCD Technologies Ltd
Priority to JP2005337871A priority Critical patent/JP2007141799A/en
Priority to US11/592,289 priority patent/US20070115685A1/en
Priority to KR1020060112670A priority patent/KR100854192B1/en
Priority to TW095142426A priority patent/TW200727047A/en
Priority to CNA2006101624188A priority patent/CN1971367A/en
Publication of JP2007141799A publication Critical patent/JP2007141799A/en
Withdrawn legal-status Critical Current

Links

Images

Classifications

    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
    • G09G3/3406—Control of illumination source
    • G09G3/342—Control of illumination source using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines
    • G09G3/3426—Control of illumination source using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines the different display panel areas being distributed in two dimensions, e.g. matrix
    • 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
    • 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
    • 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
    • G02F1/133603—Direct backlight with LEDs
    • 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
    • G02F1/133612—Electrical details
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2320/00—Control of display operating conditions
    • G09G2320/04—Maintaining the quality of display appearance
    • G09G2320/041—Temperature compensation
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2320/00—Control of display operating conditions
    • G09G2320/06—Adjustment of display parameters
    • G09G2320/0626—Adjustment of display parameters for control of overall brightness
    • G09G2320/0633—Adjustment of display parameters for control of overall brightness by amplitude modulation of the brightness of the illumination source
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2360/00—Aspects of the architecture of display systems
    • G09G2360/14—Detecting light within display terminals, e.g. using a single or a plurality of photosensors

Landscapes

  • Physics & Mathematics (AREA)
  • Nonlinear Science (AREA)
  • Engineering & Computer Science (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Chemical & Material Sciences (AREA)
  • Mathematical Physics (AREA)
  • Computer Hardware Design (AREA)
  • Theoretical Computer Science (AREA)
  • Circuit Arrangement For Electric Light Sources In General (AREA)
  • Control Of Indicators Other Than Cathode Ray Tubes (AREA)
  • Liquid Crystal (AREA)
  • Planar Illumination Modules (AREA)

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface lighting light source which gives illumination light in uniform luminance from rear side to the whole display region of a display panel of transmission type such as a liquid crystal display device. <P>SOLUTION: Electric current or voltage is supplied to an LED 71 from an LED drive/correction circuit 73. A part of luminance emitted from the LED 71 is received by a photodiode 72 and photo-electric transferred, and the photodiode 72 is reduced in resistance value in proportion to luminance. That is, when luminance of the LED 71 is increased, the resistance value of the photodiode 72 is decreased, and when the luminance of the LED 71 decreases, the resistance value of the photodiode 72 increases. This resistance value is detected by a drive/detection circuit 74, and the resistance value is returned to the LED drive/correction circuit 73. The LED drive/correction circuit 73 changes the drive current or drive voltage so that the luminance of the LED 71 may be a value corresponding to a luminance setting voltage V1. The photodiode 72 is installed for every LED 71 in 1 to 1. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

この発明は、面照明光源、該面照明光源に用いられる輝度補正回路及び輝度補正方法に係り、特に、液晶表示装置のバックライトなどのように、表示パネルの表示領域全体に対して均一な輝度で照明光を与える必要がある場合に用いて好適な面照明光源、該面照明光源に用いられる輝度補正回路及び輝度補正方法に関する。   The present invention relates to a surface illumination light source, a brightness correction circuit and a brightness correction method used for the surface illumination light source, and in particular, uniform brightness over the entire display area of a display panel such as a backlight of a liquid crystal display device. The present invention relates to a surface illumination light source suitable for use in the case where it is necessary to provide illumination light, a luminance correction circuit and a luminance correction method used for the surface illumination light source.

液晶表示装置のバックライトは、従来から冷陰極管が多く用いられているが、近年では、ＬＥＤ（Light Emitting Diode、発光ダイオード）を用いたものも製作されている。ＬＥＤバックライトでは、通常、複数のＬＥＤが直列接続され、一定電流で駆動されるようになっている。このため、個々のＬＥＤの電流輝度特性のばらつきは、そのまま、液晶表示装置の表示領域内の輝度のばらつきに反映される。ここで、ばらつきとは、電流に対する輝度特性、温度に対する輝度特性、及び、これらの輝度特性の経年変化のことである。従来、この種のばらつきを補正する技術としては、たとえば、次のような文献に記載されたものがある。   Conventionally, a cold cathode tube is often used as a backlight of a liquid crystal display device, but in recent years, a backlight using an LED (Light Emitting Diode) has been manufactured. In an LED backlight, usually, a plurality of LEDs are connected in series and driven with a constant current. For this reason, the variation in the current luminance characteristics of the individual LEDs is directly reflected in the luminance variation in the display area of the liquid crystal display device. Here, the variation is a luminance characteristic with respect to current, a luminance characteristic with respect to temperature, and a secular change of these luminance characteristics. Conventionally, techniques for correcting this type of variation include those described in the following documents, for example.

図１２は、特許文献１に記載された照明装置の要部の電気的構成を示す図である。
この照明装置は、同図に示すように、ＬＥＤ基板１０と、定電流電源２０と、温度補償回路３０とから構成されている。ＬＥＤ基板１０には、多数のＬＥＤ１１，…，１１が搭載されている。定電流電源２０は、抵抗２１と、トランジスタ２２と、増幅回路２３と、比較電圧発生回路２４とを有している。温度補償回路３０は、ＦＥＴ（Field Effect Transistor 、電界効果トランジスタ）３１と、ＬＥＤ３２と、増幅回路３３と、受光素子３４とを有している。 FIG. 12 is a diagram illustrating an electrical configuration of a main part of the lighting device described in Patent Document 1.
As shown in the figure, the lighting device includes an LED substrate 10, a constant current power source 20, and a temperature compensation circuit 30. A large number of LEDs 11,..., 11 are mounted on the LED substrate 10. The constant current power supply 20 includes a resistor 21, a transistor 22, an amplifier circuit 23, and a comparison voltage generation circuit 24. The temperature compensation circuit 30 includes a field effect transistor (FET) 31, an LED 32, an amplifier circuit 33, and a light receiving element 34.

この照明装置では、照明用のＬＥＤ１１，…，１１と同一の温度特性を有するＬＥＤ３２が発光し、この輝度が受光素子３４により電気信号に変換され、同電気信号が比較電圧発生回路２４に入力される。比較電圧発生回路２４の出力信号は増幅回路２３に入力され、同増幅回路２３の出力信号に基づいて、トランジスタ２２から一定の基準値で指定された電流がＬＥＤ１１，…，１１に供給され、同ＬＥＤ１１，…，１１の温度特性が補償される。この場合、図１３中の特性図Ｇ２に示すように、温度（気温）変化に対してＬＥＤ３２の輝度が変化した場合、比較電圧発生回路２４、増幅回路２３及びトランジスタ２２により、特性図Ｈ１に示すように、定電流電源２０の出力電流が変化し、ＬＥＤ基板１０の輝度が補正される。この結果、輝度が温度に対して変化する状態を示す特性図Ｇ１に対し、特性図Ｇ３に示すように、輝度が温度に対して変化しない特性となる。   In this lighting device, the LED 32 having the same temperature characteristics as the lighting LEDs 11,..., 11 emits light, and the luminance is converted into an electric signal by the light receiving element 34, and the electric signal is input to the comparison voltage generation circuit 24. The The output signal of the comparison voltage generation circuit 24 is input to the amplifier circuit 23. Based on the output signal of the amplifier circuit 23, a current designated by a constant reference value is supplied from the transistor 22 to the LEDs 11,. The temperature characteristics of the LEDs 11, ..., 11 are compensated. In this case, as shown in the characteristic diagram G2 in FIG. 13, when the luminance of the LED 32 changes with respect to the temperature (air temperature) change, the comparison voltage generation circuit 24, the amplifier circuit 23, and the transistor 22 show the characteristic diagram H1. As described above, the output current of the constant current power supply 20 changes, and the luminance of the LED substrate 10 is corrected. As a result, the characteristic does not change with respect to the temperature as shown in the characteristic chart G3 with respect to the characteristic diagram G1 that shows the state in which the luminance changes with respect to the temperature.

また、図１４は、従来のＬＥＤバックライトの一構成例を示す図である。
このＬＥＤバックライトでは、ＬＥＤ４１，…，４１は、赤（Ｒ），青（Ｂ），緑（Ｇ）の組合わせ、又は白色のもので構成されている。ＬＥＤ４１，…，４１は、基板４２に搭載され、所定数毎に直列接続されている。この場合、白色のＬＥＤでは、電源電圧に対応した数が直列接続され、１列に収まらない場合は、複数列に構成されて並列接続されることもある。また、Ｒ，Ｇ，ＢのＬＥＤを使用する場合、色毎の所定数のＬＥＤが直列接続される。このＬＥＤバックライトでは、ＬＥＤ４１，…，４１全体の輝度の一部が受光素子４３で電気信号に変換される。この場合、受光素子４３及びカラーフィルタ４４をＲ，Ｇ，Ｂ毎に配置するか、又は、受光素子４３の受光特性に波長依存性をもたせることにより、Ｒ，Ｇ，Ｂ毎の輝度が電気信号に変換される。この輝度に比例した電気信号を元にＬＥＤ４１，…，４１に対する駆動電流及び電圧が調整され、受光素子４３が受ける輝度が一定になるように制御される。 Moreover, FIG. 14 is a figure which shows one structural example of the conventional LED backlight.
In this LED backlight, the LEDs 41,..., 41 are composed of a combination of red (R), blue (B), green (G), or white. The LEDs 41,..., 41 are mounted on the substrate 42 and connected in series every predetermined number. In this case, in the white LED, the number corresponding to the power supply voltage is connected in series, and when it does not fit in one column, it may be configured in a plurality of columns and connected in parallel. In addition, when R, G, and B LEDs are used, a predetermined number of LEDs for each color are connected in series. In this LED backlight, a part of the luminance of the entire LEDs 41,... In this case, the light receiving element 43 and the color filter 44 are arranged for each of R, G, and B, or the light receiving characteristics of the light receiving element 43 are made wavelength dependent so that the luminance for each of R, G, and B is an electric signal Is converted to The drive current and voltage for the LEDs 41,..., 41 are adjusted based on the electrical signal proportional to the brightness, and the brightness received by the light receiving element 43 is controlled to be constant.

このため、受光素子４３の近辺のＬＥＤ４１，…，４１の輝度の変化に対しては、円滑に追従して制御されるが、離れた場所のＬＥＤ４１，…，４１の輝度の変化には、追従しにくいという問題点がある。また、基板４２の中央部では、放熱が困難なため、温度が上昇しやすい。このため、ＬＥＤ４１，…，４１の周囲温度が場所によって異なり、同ＬＥＤ４１，…，４１の温度依存性により、輝度の分布を均一にすることが困難であるという問題点がある。また、ＬＥＤ４１，…，４１の経年変化により、各ＬＥＤ４１の輝度にばらつきが発生した場合でも、受光素子４３付近のＬＥＤ４１の輝度特性が調整されるだけであるため、同ＬＥＤ４１，…，４１全体の輝度分布特性にばらつきが発生するという問題点がある。この問題点を改善するために、特許文献２では、受光素子が一箇所でなく複数箇所に設けられたＬＥＤバックライトが提案されている。   For this reason, the luminance of the LEDs 41,..., 41 in the vicinity of the light receiving element 43 is controlled to follow smoothly, but the luminance of the LEDs 41,. There is a problem that it is difficult to do. Further, in the central portion of the substrate 42, since heat radiation is difficult, the temperature is likely to rise. Therefore, there is a problem that the ambient temperature of the LEDs 41,... 41 varies depending on the location, and it is difficult to make the luminance distribution uniform due to the temperature dependence of the LEDs 41,. Further, even when the luminance of each LED 41 varies due to the aging of the LEDs 41,..., 41, only the luminance characteristics of the LED 41 in the vicinity of the light receiving element 43 are adjusted. There is a problem that the luminance distribution characteristics vary. In order to improve this problem, Patent Document 2 proposes an LED backlight in which light receiving elements are provided in a plurality of places instead of one place.

図１５は、特許文献２に記載されたバックライトのＬＥＤの配線構成を示す図である。
このバックライトでは、同図１５に示すように、基板５０上に、３１個のＬＥＤ５１が直列接続されて構成されたＬＥＤ列が４列搭載されている。 FIG. 15 is a diagram showing a wiring configuration of LEDs of a backlight described in Patent Document 2. As shown in FIG.
In this backlight, as shown in FIG. 15, four LED rows each including 31 LEDs 51 connected in series are mounted on a substrate 50.

図１６は、特許文献２に記載されたバックライトのＬＥＤの他の配線構成を示す図である。
このバックライトでは、同図１６に示すように、３個乃至７個のＬＥＤ５１が直列接続されて構成されたＬＥＤ列が多数設けられている。 FIG. 16 is a diagram showing another wiring configuration of the LED of the backlight described in Patent Document 2.
In this backlight, as shown in FIG. 16, a large number of LED rows each including three to seven LEDs 51 connected in series are provided.

図１７は、図１５又は図１６中のＬＥＤ５１が設けられたバックライトの断面図である。
このバックライト５２では、同図１７に示すように、各ＬＥＤ５１の間に各受光素子５３が配置され、同各ＬＥＤ５１の光の出射方向に拡散体５４及びＬＣＤ（Liquid Crystal Display）パネル５５が設けられている。 FIG. 17 is a cross-sectional view of a backlight provided with the LED 51 in FIG. 15 or FIG.
In the backlight 52, as shown in FIG. 17, each light receiving element 53 is arranged between the LEDs 51, and a diffuser 54 and an LCD (Liquid Crystal Display) panel 55 are provided in the light emitting direction of the LEDs 51. It has been.

図１８は、図１５又は図１６中のＬＥＤ５１の輝度特性を補正する補正回路の構成を示すブロック図である。
この補正回路では、受光素子５３の出力信号ａが検出器６１により検出され、その検出信号ｂに基づいて、制御ユニット６２によりＬＥＤ５１の輝度特性が補正される。 FIG. 18 is a block diagram showing the configuration of a correction circuit that corrects the luminance characteristics of the LED 51 in FIG. 15 or FIG.
In this correction circuit, the output signal a of the light receiving element 53 is detected by the detector 61, and the luminance characteristic of the LED 51 is corrected by the control unit 62 based on the detection signal b.

特許文献３に記載された液晶ディスプレイのバックライト制御装置では、液晶パネルの背面側にバックライトとして配置されているＬＥＤの発光光量が、同液晶パネルの周囲の明るさに応じて制御されると共に、同ＬＥＤの使用温度が変化しても、その発光光量が所定値になるように制御される。
特開２００４−２２１１５８号公報（要約書、図１、図４） 特開２００５−１１５３７２号公報（要約書、図７Ａ、図７Ｂ、図８Ｂ、図１０） 特開２００３−２１５５３４号公報（要約書、図１） In the backlight control device for a liquid crystal display described in Patent Document 3, the amount of light emitted from an LED disposed as a backlight on the back side of the liquid crystal panel is controlled according to the brightness of the surroundings of the liquid crystal panel. Even if the use temperature of the LED changes, the amount of emitted light is controlled to be a predetermined value.
JP 2004-221158 (abstract, FIGS. 1 and 4) Japanese Patent Laying-Open No. 2005-115372 (Abstract, FIGS. 7A, 7B, 8B, and 10) JP 2003-215534 A (Abstract, FIG. 1)

しかしながら、上記従来の技術では、次のような問題点があった。
すなわち、特許文献１に記載された照明装置及び特許文献２に記載されたバックライトでは、複数のＬＥＤで構成されたＬＥＤ光源に対して、このＬＥＤ光源を構成する個々のＬＥＤの輝度を検出して補正することはできない。このため、ＬＥＤの経年変化による輝度変化が生じた場合、液晶パネル内での輝度分布に変化が生じるという問題点があった。また、温度変化による輝度変化に対しても、総量の変化は補正できても、個々のＬＥＤの輝度変化の補正ではないため、液晶パネル内の輝度分布が変化するという問題点もあった。 However, the above conventional technique has the following problems.
That is, in the illumination device described in Patent Document 1 and the backlight described in Patent Document 2, the brightness of each LED constituting the LED light source is detected with respect to the LED light source composed of a plurality of LEDs. Cannot be corrected. For this reason, there has been a problem that when the luminance change due to aging of the LED occurs, the luminance distribution in the liquid crystal panel changes. In addition, even with respect to a luminance change due to a temperature change, even though the change in the total amount can be corrected, it is not a correction for the luminance change of each LED, so there is a problem that the luminance distribution in the liquid crystal panel changes.

また、この特許文献１に記載された照明装置では、ＬＥＤの温度変化や経年変化を検出する場合、実際のパネルの光源とは別のＬＥＤの輝度が参照されるようになっているが、この場合、光源のＬＥＤ及び参照用のＬＥＤの温度、温度特性、経年変化特性（寿命特性）が一致することは希有であるため、これらの特性の補正が困難になるという問題点がある。また、特許文献２に記載されたバックライトでは、複数のＬＥＤが直列接続されているが、これらのＬＥＤの輝度などの特性を個別に補正することは不可能で、実際には、複数のＬＥＤが直列接続されたＬＥＤ群の駆動電流などを調整して、同ＬＥＤ群の輝度を全体として変えることしかできなかった。また、特許文献３に記載されたバックライト制御装置は、ＬＥＤの発光輝度を液晶パネルの周囲の明るさに応じて制御するものであるため、この発明とは主旨が異なり、上記の問題点は、改善されない。   In addition, in the illumination device described in Patent Document 1, when detecting a temperature change or aging change of an LED, the brightness of the LED different from the light source of the actual panel is referred to. In this case, since it is rare that the temperature, temperature characteristics, and aging characteristics (life characteristics) of the light source LED and the reference LED match, there is a problem that it is difficult to correct these characteristics. Further, in the backlight described in Patent Document 2, a plurality of LEDs are connected in series, but it is impossible to individually correct characteristics such as luminance of these LEDs. It is only possible to adjust the drive current of the LED group connected in series to change the luminance of the LED group as a whole. Further, the backlight control device described in Patent Document 3 controls the light emission luminance of the LED in accordance with the brightness around the liquid crystal panel. Therefore, the present invention is different from the present invention. Not improved.

この発明は、上述の事情に鑑みてなされたもので、液晶表示装置などの表示パネルの表示領域全体に対して均一な輝度で照明光を与える面照明光源及び面照明光源に用いられる輝度補正回路を提供することを目的としている。   The present invention has been made in view of the above-described circumstances, and provides a surface illumination light source that provides illumination light with uniform brightness to the entire display area of a display panel such as a liquid crystal display device, and a luminance correction circuit used for the surface illumination light source. The purpose is to provide.

上記課題を解決するために、請求項１記載の発明は、複数の発光素子が面状に配列されてなり、透過型の表示パネルの表示領域に対して背面から照明光を入射させる面照明光源に係り、前記各発光素子毎に輝度を所定の目標値に設定すると共に、前記各発光素子について、その点灯時の輝度の前記目標値からのずれ量を検出し、検出された該ずれ量に基づいて前記輝度を前記目標値に一致させる輝度補正回路が設けられていることを特徴としている。   In order to solve the above-described problem, the invention according to claim 1 is a surface illumination light source in which a plurality of light emitting elements are arranged in a planar shape, and illumination light is incident on the display area of a transmissive display panel from the back side. Therefore, the luminance is set to a predetermined target value for each of the light emitting elements, and the deviation amount of the luminance at the time of lighting from the target value is detected for each of the light emitting elements, and the detected deviation amount is set to the detected deviation amount. A luminance correction circuit for matching the luminance with the target value is provided.

請求項２記載の発明は、請求項１記載の面照明光源に係り、前記輝度補正回路は、前記複数の発光素子に対して１対１で設けられ、前記各発光素子から放射される光を受光し、その輝度に対応したレベルの輝度検出信号を生成する複数の受光素子と、前記複数の発光素子に対して１対１で設けられ、前記各発光素子に対して駆動用電力を供給すると共に、前記輝度検出信号のレベルに基づいて当該発光素子の前記輝度の各目標値に対する偏差を検出し、該偏差を補償するように前記駆動用電力を補正する駆動／補正回路とから構成されていることを特徴としている。   A second aspect of the present invention relates to the surface illumination light source according to the first aspect, wherein the luminance correction circuit is provided one-to-one with respect to the plurality of light emitting elements, and emits light emitted from the light emitting elements. A plurality of light receiving elements that receive light and generate a luminance detection signal of a level corresponding to the luminance, and a one-to-one correspondence with the plurality of light emitting elements, and supply driving power to each of the light emitting elements And a drive / correction circuit that detects a deviation of the luminance of the light emitting element from each target value based on the level of the luminance detection signal and corrects the driving power so as to compensate for the deviation. It is characterized by being.

請求項３記載の発明は、請求項２記載の面照明光源に係り、前記各発光素子と前記各受光素子とが１対１で近接配置されていることを特徴としている。   According to a third aspect of the present invention, there is provided the surface illumination light source according to the second aspect, wherein the light emitting elements and the light receiving elements are arranged close to each other in a one-to-one relationship.

請求項４記載の発明は、請求項３記載の面照明光源に係り、前記各発光素子と前記各受光素子とが同一のパッケージに搭載されていることを特徴としている。   According to a fourth aspect of the present invention, there is provided the surface illumination light source according to the third aspect, wherein the light emitting elements and the light receiving elements are mounted in the same package.

請求項５記載の発明は、輝度補正回路に係り、複数の発光素子が面状に配列されてなり、透過型の表示パネルの表示領域に対して背面から照明光を入射させる面照明光源に用いられ、前記各発光素子毎に輝度を所定の目標値に設定すると共に、前記各発光素子について、その点灯時の輝度の前記目標値からのずれ量を検出し、検出された該ずれ量に基づいて前記輝度を前記目標値に一致させる構成とされていることを特徴としている。   The invention according to claim 5 relates to a luminance correction circuit, and is used as a surface illumination light source in which a plurality of light emitting elements are arranged in a planar shape, and illumination light is incident on the display area of a transmissive display panel from the back side. The luminance is set to a predetermined target value for each of the light emitting elements, and the amount of deviation of the luminance at the time of lighting from the target value is detected for each of the light emitting elements, and based on the detected amount of deviation The brightness is made to coincide with the target value.

請求項６記載の発明は、請求項５記載の輝度補正回路に係り、前記複数の発光素子に対して１対１で設けられ、前記各発光素子から放射される光を受光し、その輝度に対応したレベルの輝度検出信号を生成する複数の受光素子と、前記複数の発光素子に対して１対１で設けられ、前記各発光素子に対して駆動用電力を供給すると共に、前記輝度検出信号のレベルに基づいて当該発光素子の前記輝度の各目標値に対する偏差を検出し、該偏差を補償するように前記駆動用電力を補正する駆動／補正回路とから構成されていることを特徴としている。   A sixth aspect of the present invention relates to the luminance correction circuit according to the fifth aspect, wherein the plurality of light emitting elements are provided on a one-to-one basis, receive light emitted from the light emitting elements, and adjust the luminance thereof. A plurality of light receiving elements that generate a luminance detection signal of a corresponding level and a one-to-one correspondence with each of the plurality of light emitting elements, supplying driving power to each of the light emitting elements, and the luminance detection signal And a drive / correction circuit that detects the deviation of the luminance of the light-emitting element from the target values and corrects the driving power so as to compensate for the deviation. .

請求項７記載の発明は、輝度補正方法に係り、複数の発光素子が面状に配列されてなり、透過型の表示パネルの表示領域に対して背面から照明光を入射させる面照明光源に用いられ、前記各発光素子毎に輝度を所定の目標値に設定すると共に、前記各発光素子について、その点灯時の輝度の前記目標値からのずれ量を検出し、検出された該ずれ量に基づいて前記輝度を前記目標値に一致させることを特徴としている。   The invention according to claim 7 relates to a luminance correction method, and is used for a surface illumination light source in which a plurality of light emitting elements are arranged in a planar shape, and illumination light is incident on the display area of a transmissive display panel from the back side. The luminance is set to a predetermined target value for each of the light emitting elements, and the deviation amount of the luminance at the time of lighting from the target value is detected for each of the light emitting elements, and based on the detected deviation amount The brightness is made to coincide with the target value.

この発明の構成によれば、各発光素子毎に輝度を所定の目標値に設定すると共に、同各発光素子の輝度の同目標値からのずれ量を検出し、同ずれ量に基づいて同輝度を目標値に一致させる輝度補正回路が設けられているので、各発光素子の輝度を均一にでき、かつ表示パネルの表示領域全体の明るさを均一にできる。また、各発光素子の輝度が１対１で各受光素子で輝度検出信号に変換され、同輝度検出信号が駆動／補正回路に帰還されるので、同各発光素子の輝度のばらつき及び変化を自動で補償できる。また、各発光素子の輝度が帰還されるため、温度変化量のみを抽出して帰還する必要がないので、同各発光素子の温度補正回路を不要にできる。また、各発光素子と各受光素子とが同一のパッケージに１対１で近接配置されているため、同各発光素子の輝度が個々に補正されるので、同各発光素子及び各受光素子にばらつきがあっても、輝度の目標値を適切に設定することにより、各発光素子の輝度を均一にできる。また、各発光素子と各受光素子とが１対１で対応しているため、同各発光素子がＲ，Ｇ，Ｂのいずれの発光色のものでも、カラーフィルタを用いることなく、カラーバランスの変化を補償できる。従って、この面照明光源を、たとえば透過型の液晶パネルのバックライトとして用いると、同液晶パネルの表示領域全体に対して均一な輝度で照明光を与えることができる。   According to the configuration of the present invention, the luminance is set to a predetermined target value for each light emitting element, the amount of deviation of the luminance of each light emitting element from the target value is detected, and the luminance is based on the amount of deviation. Since the luminance correction circuit that matches the target value is provided, the luminance of each light emitting element can be made uniform, and the brightness of the entire display area of the display panel can be made uniform. In addition, the luminance of each light emitting element is 1: 1 and converted to a luminance detection signal by each light receiving element, and the luminance detection signal is fed back to the drive / correction circuit. Can compensate. Further, since the luminance of each light emitting element is fed back, it is not necessary to extract only the amount of temperature change and feed back, so that the temperature correction circuit for each light emitting element can be made unnecessary. In addition, since each light emitting element and each light receiving element are arranged close to each other in the same package on a one-to-one basis, the luminance of each light emitting element is individually corrected, so that the light emitting element and the light receiving element vary. Even if there is, the brightness of each light emitting element can be made uniform by appropriately setting the target value of brightness. In addition, since each light emitting element and each light receiving element have a one-to-one correspondence, even if each light emitting element has any of R, G, and B emission colors, color balance can be achieved without using a color filter. Can compensate for changes. Therefore, when this surface illumination light source is used as, for example, a backlight of a transmissive liquid crystal panel, illumination light can be given to the entire display area of the liquid crystal panel with uniform luminance.

各ＬＥＤ（発光素子）の輝度が１対１で各受光素子で輝度検出信号に変換され、同輝度検出信号が輝度補正回路に帰還される面照明光源及び面照明光源に用いられる輝度補正回路を提供する。   A luminance correction circuit used for a surface illumination light source and a surface illumination light source in which the luminance of each LED (light emitting element) is converted into a luminance detection signal by each light receiving element on a one-to-one basis and the luminance detection signal is fed back to the luminance correction circuit. provide.

図１は、この発明の第１の実施例である面照明光源の要部の電気的構成を示すブロック図である。
この例の面照明光源は、たとえば液晶表示装置に設けられている透過型の液晶パネルのバックライトとして用いられ、同図に示すように、ＬＥＤ７１と、ホトダイオード７２と、ＬＥＤ駆動／補正回路７３と、駆動／検出回路７４とから構成されている。ＬＥＤ７１は、この図では、１個で表示されているが、バックライトとして複数個からなり、平面状に配列されている。ホトダイオード７２は、各ＬＥＤ７１毎に１対１で設けられ、当該ＬＥＤ７１からの光を受光し、その輝度に対応したレベルの輝度検出電圧ａを生成する。駆動／検出回路７４は、ホトダイオード７２毎に１対１で設けられ、同ホトダイオード７２に電力を供給すると共に、同ホトダイオード７２からの輝度検出電圧ａを、そのまま輝度検出電圧Ｖ2 としてＬＥＤ駆動／補正回路７３へ送出する。 FIG. 1 is a block diagram showing the electrical configuration of the main part of a surface illumination light source according to the first embodiment of the present invention.
The surface illumination light source of this example is used as, for example, a backlight of a transmissive liquid crystal panel provided in a liquid crystal display device, and as shown in the figure, an LED 71, a photodiode 72, an LED drive / correction circuit 73, Drive / detection circuit 74. Although one LED 71 is displayed in this figure, it is composed of a plurality of backlights and arranged in a plane. The photodiode 72 is provided on a one-to-one basis for each LED 71, receives light from the LED 71, and generates a luminance detection voltage a having a level corresponding to the luminance. The drive / detection circuit 74 is provided on a one-to-one basis for each photodiode 72, supplies power to the photodiode 72, and uses the luminance detection voltage a from the photodiode 72 as the luminance detection voltage V2 as it is as an LED drive / correction circuit. To 73.

ＬＥＤ駆動／補正回路７３は、各ＬＥＤ７１毎に１対１で設けられ、当該ＬＥＤ７１に対して駆動用電力ｃを供給すると共に、駆動／検出回路７４からの輝度検出電圧Ｖ2 のレベルに基づいて当該ＬＥＤ７１の輝度の各目標値（輝度設定電圧Ｖ1 に対応した値）に対する偏差を検出し、同偏差を補償するように駆動用電力ｃを補正する。特に、この実施例では、ＬＥＤ駆動／補正回路７３は、たとえば、当該ＬＥＤ７１の輝度の低下に応じて、供給する電流を増大する。これらのホトダイオード７２、ＬＥＤ駆動／補正回路７３及び駆動／検出回路７４で、輝度補正回路が構成されている。輝度補正回路は、各ＬＥＤ７１毎に輝度を所定の目標値に設定すると共に、同各ＬＥＤ７１の輝度の同目標値からのずれ量を検出し、同各ずれ量に基づいて同各輝度を同各目標値に一致させる。   The LED drive / correction circuit 73 is provided on a one-to-one basis for each LED 71, supplies driving power c to the LED 71, and based on the level of the luminance detection voltage V2 from the drive / detection circuit 74. Deviations with respect to each target value (value corresponding to the luminance setting voltage V1) of the luminance of the LED 71 are detected, and the driving power c is corrected so as to compensate for the deviation. In particular, in this embodiment, the LED drive / correction circuit 73 increases the supplied current in accordance with, for example, a decrease in the luminance of the LED 71. The photodiode 72, the LED drive / correction circuit 73, and the drive / detection circuit 74 constitute a luminance correction circuit. The luminance correction circuit sets the luminance for each LED 71 to a predetermined target value, detects the amount of deviation of the luminance of the LED 71 from the target value, and determines the luminance based on the amount of deviation. Match the target value.

図２は、図１中のＬＥＤ駆動／補正回路７３及び駆動／検出回路７４の電気的構成の一例を示す回路図である。
このＬＥＤ駆動／補正回路７３は、同図２に示すように、抵抗８１，８２，８３，８４と、オペアンプ（演算増幅器）８５と、抵抗８６，８７，８８と、オペアンプ８９と、抵抗９０と、オペアンプ９１と、抵抗９２とから構成されている。また、駆動／検出回路７４は、定電流回路９３と、オペアンプ９４とから構成されている。 FIG. 2 is a circuit diagram showing an example of the electrical configuration of the LED drive / correction circuit 73 and the drive / detection circuit 74 in FIG.
As shown in FIG. 2, the LED drive / correction circuit 73 includes resistors 81, 82, 83, 84, an operational amplifier (operational amplifier) 85, resistors 86, 87, 88, an operational amplifier 89, and a resistor 90. , An operational amplifier 91 and a resistor 92. The drive / detection circuit 74 includes a constant current circuit 93 and an operational amplifier 94.

図３は、図１中のＬＥＤ７１、ホトダイオード７２、ＬＥＤ駆動／補正回路７３及び駆動／検出回路７４の配置状態の例を示す図である。
同図３に示すように、これらのＬＥＤ７１、ホトダイオード７２、ＬＥＤ駆動／補正回路７３及び駆動／検出回路７４は、１個づつ基板７５上に配置されている。この場合、ＬＥＤ７１は、透明な樹脂などで封止された形状のものや、ベアチップの状態のものである。ベアチップの場合、基板７５のＬＥＤ７１の搭載部の一部又は全部を樹脂などで封止することが望ましい。また、特に、この実施例では、ＬＥＤ７１とホトダイオード７２とが１対１で近接配置され、ＬＥＤ駆動／補正回路７３及び駆動／検出回路７４が一体化されている。 FIG. 3 is a diagram showing an example of an arrangement state of the LED 71, the photodiode 72, the LED drive / correction circuit 73, and the drive / detection circuit 74 in FIG.
As shown in FIG. 3, the LED 71, the photodiode 72, the LED drive / correction circuit 73, and the drive / detection circuit 74 are arranged on the substrate 75 one by one. In this case, the LED 71 has a shape sealed with a transparent resin or the like, or a bare chip. In the case of a bare chip, it is desirable to seal part or all of the LED 71 mounting portion of the substrate 75 with resin or the like. In particular, in this embodiment, the LEDs 71 and the photodiodes 72 are arranged close to each other on a one-to-one basis, and the LED drive / correction circuit 73 and the drive / detection circuit 74 are integrated.

図４は、図１中のＬＥＤ７１、ホトダイオード７２、ＬＥＤ駆動／補正回路７３及び駆動／検出回路７４の配置状態の他の例を示す図である。
同図４に示すように、基板７５上に、ＬＥＤ７１、ホトダイオード７２、ＬＥＤ駆動／補正回路７３及び駆動／検出回路７４の組が、たとえば２０組配置されている。この場合、ある組のホトダイオード７２が隣接する組のＬＥＤ７１の光を受けた場合、本来補償すべきＬＥＤ７１以外の光の影響を受けることになるので、他のＬＥＤ７１からの光を遮光するなどの構造的な対策を行うことが望ましい。 FIG. 4 is a diagram showing another example of the arrangement state of the LED 71, the photodiode 72, the LED drive / correction circuit 73, and the drive / detection circuit 74 in FIG.
As shown in FIG. 4, for example, 20 sets of LED 71, photodiode 72, LED drive / correction circuit 73 and drive / detection circuit 74 are arranged on a substrate 75. In this case, when a certain group of photodiodes 72 receives light from an adjacent group of LEDs 71, it is affected by light other than the LED 71 that should be compensated for, so that the light from the other LEDs 71 is blocked. It is desirable to take specific measures.

この面照明光源に用いられる輝度補正方法では、各ＬＥＤ７１毎に輝度が所定の目標値に設定されると共に、同各ＬＥＤ７１について、その点灯時の輝度の同目標値からのずれ量が検出され、検出された同ずれ量に基づいて輝度が同目標値に一致するように補正される。この場合、図１中のＬＥＤ駆動／補正回路７３からＬＥＤ７１に電流又は電圧が供給される。このとき、駆動方法は、定電流駆動でも定電圧駆動でも良い。発光したＬＥＤ７１の輝度の一部がホトダイオード７２で受光されて光／電気変換され、同ホトダイオード７２は、輝度に比例して抵抗値が低下する。つまり、ＬＥＤ７１の輝度が上がれば、ホトダイオード７２の抵抗値が低下し、同ＬＥＤ７１の輝度が下がれば、ホトダイオード７２の抵抗値が増加する。この抵抗値が駆動／検出回路７４で検出され、同抵抗値がＬＥＤ駆動／補正回路７３に帰還される。ＬＥＤ駆動／補正回路７３は、ＬＥＤ７１の輝度が輝度設定電圧Ｖ1 に対応した値になるように、駆動電流又は駆動電圧を変化させる。   In the luminance correction method used for this surface illumination light source, the luminance is set to a predetermined target value for each LED 71, and the deviation amount of the luminance at the time of lighting from the target value is detected for each LED 71, Based on the detected amount of deviation, the luminance is corrected so as to match the target value. In this case, current or voltage is supplied to the LED 71 from the LED drive / correction circuit 73 in FIG. At this time, the driving method may be constant current driving or constant voltage driving. A part of the luminance of the emitted LED 71 is received by the photodiode 72 and subjected to optical / electrical conversion, and the resistance value of the photodiode 72 decreases in proportion to the luminance. That is, if the brightness of the LED 71 increases, the resistance value of the photodiode 72 decreases, and if the brightness of the LED 71 decreases, the resistance value of the photodiode 72 increases. This resistance value is detected by the drive / detection circuit 74, and the resistance value is fed back to the LED drive / correction circuit 73. The LED driving / correcting circuit 73 changes the driving current or the driving voltage so that the luminance of the LED 71 becomes a value corresponding to the luminance setting voltage V1.

すなわち、図２に示すように、ＬＥＤ７１の駆動電流を決定するために、輝度設定電圧Ｖ1 が入力され、同ＬＥＤ７１の輝度が電圧で設定される。そして、ＬＥＤ駆動／補正回路７３から電流Ｉ0 がＬＥＤ７１に供給される。この電流Ｉ0 は、次式（１）で表される。
Ｉ0 ＝Ｖ3 ／ＲSC ・・・（１）
但し、
ＲSC；抵抗９０の抵抗値
この電流Ｉ0 の値を決める電圧Ｖ3 は、オペアンプ８５により構成された加減算回路の出力電圧であり、次式（２）で表される。
Ｖ3 ＝（−Ｒ2 ／Ｒ1 ）×Ｖ1 ＋（Ｒ4 ／Ｒ3 ）×Ｖ2 ・・・（２）
但し、
Ｒ1 ；抵抗８１の抵抗値
Ｒ2 ；抵抗８２の抵抗値
Ｒ3 ；抵抗８３の抵抗値
Ｒ4 ；抵抗８４の抵抗値 That is, as shown in FIG. 2, in order to determine the drive current of the LED 71, the luminance setting voltage V1 is input, and the luminance of the LED 71 is set as a voltage. Then, the current I 0 is supplied from the LED drive / correction circuit 73 to the LED 71. This current I0 is expressed by the following equation (1).
I0 = V3 / RSC (1)
However,
RSC: Resistance value of the resistor 90 The voltage V3 that determines the value of the current I0 is the output voltage of the adder / subtractor circuit constituted by the operational amplifier 85 and is expressed by the following equation (2).
V3 = (-R2 / R1) * V1 + (R4 / R3) * V2 (2)
However,
R1: Resistance value of the resistor 81
R2: Resistance value of resistor 82
R3: Resistance value of resistor 83
R4: Resistance value of resistor 84

輝度検出電圧Ｖ2 は、ホトダイオード７２の駆動電圧がオペアンプ９４によるボルテージホロアを経てＬＥＤ駆動／補正回路７３へ帰還されているものである。このホトダイオード７２は、定電流回路９３により駆動されているので、ＬＥＤ７１の輝度に対応した抵抗値をもつ。すなわち、ＬＥＤ７１の輝度が低下したとき、ホトダイオード７２の抵抗値が増加し、同ホトダイオード７２の駆動電圧が増加して輝度検出電圧Ｖ2 が増加する。輝度検出電圧Ｖ2 が増加すると、式（２）に基づいて、同輝度検出電圧Ｖ2 のＲ4 ／Ｒ3 倍の電圧により電圧Ｖ3 が増加する。電圧Ｖ3 が増加すれば、ＬＥＤ７１の駆動電流が増加し、輝度が増大する。従って、抵抗値Ｒ1 ，Ｒ2 ，Ｒ3 ，Ｒ4 、及び定電流回路９３の電流値Ｉd を選択することにより、ＬＥＤ７１の輝度変化に応じて、ホトダイオード７２による帰還が掛かり、輝度変化が補償される。   The luminance detection voltage V2 is obtained by feeding back the drive voltage of the photodiode 72 to the LED drive / correction circuit 73 through the voltage follower by the operational amplifier 94. Since the photodiode 72 is driven by the constant current circuit 93, the photodiode 72 has a resistance value corresponding to the luminance of the LED 71. That is, when the luminance of the LED 71 decreases, the resistance value of the photodiode 72 increases, the driving voltage of the photodiode 72 increases, and the luminance detection voltage V2 increases. When the luminance detection voltage V2 increases, the voltage V3 increases by a voltage R4 / R3 times the luminance detection voltage V2 based on the equation (2). When the voltage V3 increases, the drive current of the LED 71 increases and the luminance increases. Therefore, by selecting the resistance values R1, R2, R3, R4 and the current value Id of the constant current circuit 93, feedback by the photodiode 72 is applied according to the luminance change of the LED 71, and the luminance change is compensated.

以上のように、この第１の実施例では、各ＬＥＤ７１の輝度が１対１で各ホトダイオード７２で輝度検出電圧Ｖ2 に変換され、同輝度検出電圧Ｖ2 が駆動／検出回路７４に帰還されるので、同各ＬＥＤ７１の輝度のばらつき及び変化が自動で補償される。また、各ＬＥＤ７１の輝度が帰還されるため、温度変化量のみを抽出して帰還する必要がないので、同各ＬＥＤ７１の温度補正回路が不要となる。また、各ＬＥＤ７１と各ホトダイオード７２とが１対１で近接配置されているため、同各ＬＥＤ７１の輝度が個々に補正されるので、同各ＬＥＤ７１及び各ホトダイオード７２にばらつきがあっても、輝度設定電圧Ｖ1 を適切に設定することにより、各ＬＥＤ７１の輝度が均一となる。また、各ＬＥＤ７１と各ホトダイオード７２とが１対１で対応しているため、同各ＬＥＤ７１がＲ，Ｇ，Ｂのいずれの発光色のものでも、カラーフィルタを用いることなく、カラーバランスの変化が補償される。   As described above, in this first embodiment, the brightness of each LED 71 is 1: 1 and converted to the brightness detection voltage V2 by each photodiode 72, and the brightness detection voltage V2 is fed back to the drive / detection circuit 74. The variation and change in luminance of each LED 71 are automatically compensated. Further, since the brightness of each LED 71 is fed back, it is not necessary to extract only the temperature change amount and feed back, so that the temperature correction circuit for each LED 71 becomes unnecessary. Further, since each LED 71 and each photodiode 72 are arranged close to each other in a one-to-one relationship, the brightness of each LED 71 is individually corrected. By appropriately setting the voltage V1, the brightness of each LED 71 becomes uniform. In addition, since each LED 71 and each photodiode 72 have a one-to-one correspondence, even if each LED 71 has an emission color of R, G, or B, the color balance can be changed without using a color filter. Compensated.

図５は、この発明の第２の実施例である面照明光源の要部の配置状態を示す断面図であり、第１の実施例を示す図４中の要素と共通の要素には共通の符号が付されている。
この例の面照明光源では、同図５に示すように、ＬＥＤ７１、ホトダイオード７２、ＬＥＤ駆動／補正回路７３及び駆動／検出回路７４が同一のパッケージ７６に搭載されている。また、パッケージ７６には、外部と接続するための図示しない端子などが形成されている。この面照明光源では、ＬＥＤ７１とホトダイオード７２とがパッケージ７６に１対１で近接配置されると共に、ＬＥＤ駆動／補正回路７３及び駆動／検出回路７４が一体化され、上記第１の実施例と同様の利点がある。 FIG. 5 is a cross-sectional view showing the arrangement of the main part of the surface illumination light source according to the second embodiment of the present invention, which is common to the elements common to the elements in FIG. 4 showing the first embodiment. The code | symbol is attached | subjected.
In the surface illumination light source of this example, as shown in FIG. 5, the LED 71, the photodiode 72, the LED drive / correction circuit 73 and the drive / detection circuit 74 are mounted on the same package 76. The package 76 is formed with terminals (not shown) for connection to the outside. In this surface illumination light source, the LED 71 and the photodiode 72 are arranged close to the package 76 on a one-to-one basis, and the LED drive / correction circuit 73 and the drive / detection circuit 74 are integrated, which is the same as in the first embodiment. There are advantages.

図６は、この発明の第３の実施例である面照明光源の要部の配置状態を示す断面図であり、第２の実施例を示す図５中の要素と共通の要素には共通の符号が付されている。
この例の面照明光源では、同図６に示すように、図５中のホトダイオード７２、ＬＥＤ駆動／補正回路７３及び駆動／検出回路７４が一体化されて１つのＩＣ（集積回路）７７として構成されている。この面照明光源では、上記第１の実施例と同様に、ＬＥＤ７１とホトダイオード７２とが１対１で近接配置され、同様の利点がある。 FIG. 6 is a sectional view showing the arrangement of the main part of the surface illumination light source according to the third embodiment of the present invention, and is common to the elements common to the elements in FIG. 5 showing the second embodiment. The code | symbol is attached | subjected.
In the surface illumination light source of this example, as shown in FIG. 6, the photodiode 72, the LED drive / correction circuit 73 and the drive / detection circuit 74 in FIG. Has been. In this surface illumination light source, as in the first embodiment, the LEDs 71 and the photodiodes 72 are arranged close to each other on a one-to-one basis and have the same advantages.

図７は、この発明の第４の実施例である面照明光源の要部の配置状態を示す断面図である。
この例の面照明光源では、同図７に示すように、ＬＥＤ駆動／補正回路７３及び駆動／検出回路７４が、パッケージ７６の外部にあり、同パッケージ７６と共に基板７５上に搭載されている。この基板７５は、有機系材料又は無機系材料で形成されている。この面照明光源では、上記第１の実施例と同様に、ＬＥＤ７１とホトダイオード７２とが１対１で近接配置され、同様の利点がある。 FIG. 7 is a sectional view showing the arrangement of the main part of the surface illumination light source according to the fourth embodiment of the present invention.
In the surface illumination light source of this example, as shown in FIG. 7, the LED drive / correction circuit 73 and the drive / detection circuit 74 are outside the package 76 and are mounted on the substrate 75 together with the package 76. The substrate 75 is made of an organic material or an inorganic material. In this surface illumination light source, as in the first embodiment, the LEDs 71 and the photodiodes 72 are arranged close to each other in a one-to-one relationship and have the same advantages.

図８は、この発明の第５の実施例である面照明光源の要部の配置状態を示す断面図である。
この例の面照明光源では、同図８に示すように、図６と同様のパッケージ７６が基板７５上に搭載され、また、新たに補正素子７８が同基板７５上に搭載されている。補正素子７８は、たとえば、可変抵抗器、レーザでトリミングされる圧膜印刷抵抗素子、抵抗とツェナ・ダイオードとで構成されるツェナ・ザップ素子、又は輝度の各目標値に対応したデータを書込み可能なメモリ素子などで構成され、ＬＥＤ駆動／補正回路７３に輝度設定電圧Ｖ1 を与える。この面照明光源では、各ＬＥＤ７１及び各ホトダイオード７２にばらつきがあっても、補正素子７８により輝度設定電圧Ｖ1 が適切に設定されることにより、各ＬＥＤ７１の輝度が均一となる。 FIG. 8 is a sectional view showing the arrangement of the main part of the surface illumination light source according to the fifth embodiment of the present invention.
In the surface illumination light source of this example, as shown in FIG. 8, a package 76 similar to that in FIG. 6 is mounted on the substrate 75, and a correction element 78 is newly mounted on the substrate 75. The correction element 78 can write, for example, a variable resistor, a pressure film printing resistance element trimmed by a laser, a zener zap element composed of a resistor and a zener diode, or data corresponding to each target value of luminance. A brightness setting voltage V1 is applied to the LED drive / correction circuit 73. In this surface illumination light source, even if each LED 71 and each photodiode 72 have variations, the brightness of each LED 71 becomes uniform by appropriately setting the brightness setting voltage V1 by the correction element 78.

図９は、この発明の第６の実施例である面照明光源の要部の配置状態を示す断面図であり、第４の実施例を示す図７中の要素及び第５の実施例を示す図８中の要素と共通の要素には共通の符号が付されている。
この例の面照明光源では、同図９に示すように、図７中の基板７５上に図８中の補正素子７８が搭載されている。この面照明光源では、各ＬＥＤ７１及び各ホトダイオード７２にばらつきがあっても、上記第８の実施例と同様に、補正素子７８により輝度設定電圧Ｖ1 が適切に設定されることにより、各ＬＥＤ７１の輝度が均一となる。 FIG. 9 is a sectional view showing the arrangement of the main part of the surface illumination light source according to the sixth embodiment of the present invention, showing the elements in FIG. 7 showing the fourth embodiment and the fifth embodiment. Elements common to the elements in FIG. 8 are given common reference numerals.
In the surface illumination light source of this example, as shown in FIG. 9, the correction element 78 in FIG. 8 is mounted on the substrate 75 in FIG. In this surface illumination light source, even if each LED 71 and each photodiode 72 have variations, the brightness setting voltage V1 is appropriately set by the correction element 78 in the same manner as in the eighth embodiment, whereby the brightness of each LED 71 is set. Becomes uniform.

図１０は、この発明の第７の実施例である面照明光源の要部の配置状態を示す断面図であり、第６の実施例を示す図９中の要素と共通の要素には共通の符号が付されている。
この例の面照明光源では、同図１０に示すように、図９中のＬＥＤ駆動／補正回路７３及び駆動／検出回路７４と、補正素子７８とが一体化されて１つのＩＣ７９として構成されている。この面照明光源では、各ＬＥＤ７１及び各ホトダイオード７２にばらつきがあっても、上記第８の実施例と同様に、ＩＣ７９の補正素子７８により輝度設定電圧Ｖ1 が適切に設定されることにより、各ＬＥＤ７１の輝度が均一となる。 FIG. 10 is a cross-sectional view showing the arrangement of the main part of the surface illumination light source according to the seventh embodiment of the present invention, and is common to the elements common to the elements in FIG. 9 showing the sixth embodiment. The code | symbol is attached | subjected.
In the surface illumination light source of this example, as shown in FIG. 10, the LED drive / correction circuit 73 and the drive / detection circuit 74 and the correction element 78 in FIG. 9 are integrated into a single IC 79. Yes. In this surface illumination light source, even if each LED 71 and each photodiode 72 vary, the brightness setting voltage V1 is appropriately set by the correction element 78 of the IC 79 as in the case of the eighth embodiment. The brightness becomes uniform.

図１１は、この発明の第８の実施例である面照明光源に用いられる輝度補正回路の電気的構成を示す回路図であり、第１の実施例を示す図２中の要素と共通の要素には共通の符号が付されている。
この例の輝度補正回路では、同図１１に示すように、図２中のＬＥＤ駆動／補正回路７３に代えて、異なる構成のＬＥＤ駆動／補正回路７３Ａが設けられている。ＬＥＤ駆動／補正回路７３Ａは、抵抗８１，８２，８３，８４と、オペアンプ８５と、オペアンプ９５と、ｎチャネル型ＭＯＳＦＥＴ（ｎＭＯＳ）９６と、可変抵抗９７とから構成されている。 FIG. 11 is a circuit diagram showing an electrical configuration of a luminance correction circuit used in the surface illumination light source according to the eighth embodiment of the present invention, and is common to the elements in FIG. 2 showing the first embodiment. Are denoted by common reference numerals.
In the luminance correction circuit of this example, as shown in FIG. 11, an LED drive / correction circuit 73A having a different configuration is provided instead of the LED drive / correction circuit 73 in FIG. The LED drive / correction circuit 73A includes resistors 81, 82, 83, and 84, an operational amplifier 85, an operational amplifier 95, an n-channel MOSFET (nMOS) 96, and a variable resistor 97.

この輝度補正回路では、ＬＥＤ７１に流れる電流Ｉ0 は、次式（３）で表される。
Ｉ0 ＝Ｖ4 ／ＲICC ・・・（３）
但し、
ＲICC ；可変抵抗９７の抵抗値
この輝度補正回路は、オペアンプ９５の非反転入力端子（＋）の電圧Ｖ3 と反転入力端子（−）の電圧とが同じになるように動作するので、電圧Ｖ3 と電圧Ｖ4 とは、ほぼ同じになる。この電圧Ｖ4 と可変抵抗９７の抵抗値ＲICC とにより、ＬＥＤ７１に流れる電流Ｉ0 が決まる。また、抵抗値ＲICC を調整することにより、ＬＥＤ７１に所望の電流が流れ、同ＬＥＤ７１が所望の輝度で発光する。また、オペアンプ８５は、第１の実施例と同様に加減算回路を構成しているので、輝度設定電圧Ｖ1 を変えることにより電圧Ｖ3 が変化する。このように、第１の実施例とは異なる構成の輝度補正回路により、ほぼ同様の利点が得られる。 In this luminance correction circuit, the current I0 flowing through the LED 71 is expressed by the following equation (3).
I0 = V4 / RICC (3)
However,
RICC: Resistance value of variable resistor 97 Since this brightness correction circuit operates so that the voltage V3 of the non-inverting input terminal (+) of the operational amplifier 95 and the voltage of the inverting input terminal (-) become the same, the voltage V3 The voltage V4 is almost the same. The voltage V4 and the resistance value RICC of the variable resistor 97 determine the current I0 flowing through the LED 71. Further, by adjusting the resistance value RICC, a desired current flows through the LED 71, and the LED 71 emits light with a desired luminance. Since the operational amplifier 85 constitutes an addition / subtraction circuit as in the first embodiment, the voltage V3 is changed by changing the luminance setting voltage V1. As described above, the luminance correction circuit having a configuration different from that of the first embodiment provides almost the same advantage.

以上、この発明の実施例を図面により詳述してきたが、具体的な構成は同実施例に限られるものではなく、この発明の要旨を逸脱しない範囲の設計の変更などがあっても、この発明に含まれる。
たとえば、図２又は図１１に示す輝度補正回路の構成は、同様の機能を有するものであれば、他の回路構成でも良い。 The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to the embodiment, and even if there is a design change without departing from the gist of the present invention, Included in the invention.
For example, the configuration of the luminance correction circuit illustrated in FIG. 2 or 11 may be another circuit configuration as long as it has a similar function.

この発明は、液晶表示装置のバックライトなどのように、表示パネルの表示領域全体に対して均一な輝度で照明光を与える必要がある場合全般に適用できる。   The present invention can be generally applied to a case where illumination light needs to be given with uniform luminance to the entire display area of a display panel, such as a backlight of a liquid crystal display device.

この発明の第１の実施例である面照明光源の要部の電気的構成を示すブロック図である。It is a block diagram which shows the electric constitution of the principal part of the surface illumination light source which is 1st Example of this invention. 図１中のＬＥＤ駆動／補正回路７３及び駆動／検出回路７４の電気的構成を示す回路図である。FIG. 2 is a circuit diagram showing an electrical configuration of an LED drive / correction circuit 73 and a drive / detection circuit 74 in FIG. 1. 図１中のＬＥＤ７１、ホトダイオード７２、ＬＥＤ駆動／補正回路７３及び駆動／検出回路７４の配置状態の例を示す図である。It is a figure which shows the example of arrangement | positioning state of LED71 in FIG. 1, the photodiode 72, the LED drive / correction circuit 73, and the drive / detection circuit 74. FIG. 図１中のＬＥＤ７１、ホトダイオード７２、ＬＥＤ駆動／補正回路７３及び駆動／検出回路７４の配置状態の他の例を示す図である。It is a figure which shows the other example of arrangement | positioning state of LED71 in FIG. 1, the photodiode 72, the LED drive / correction circuit 73, and the drive / detection circuit 74. FIG. この発明の第２の実施例である面照明光源の要部の配置状態を示す断面図である。It is sectional drawing which shows the arrangement | positioning state of the principal part of the surface illumination light source which is 2nd Example of this invention. この発明の第３の実施例である面照明光源の要部の配置状態を示す断面図である。It is sectional drawing which shows the arrangement | positioning state of the principal part of the surface illumination light source which is the 3rd Example of this invention. この発明の第４の実施例である面照明光源の要部の配置状態を示す断面図である。It is sectional drawing which shows the arrangement | positioning state of the principal part of the surface illumination light source which is the 4th Example of this invention. この発明の第５の実施例である面照明光源の要部の配置状態を示す断面図である。It is sectional drawing which shows the arrangement | positioning state of the principal part of the surface illumination light source which is 5th Example of this invention. この発明の第６の実施例である面照明光源の要部の配置状態を示す断面図である。It is sectional drawing which shows the arrangement | positioning state of the principal part of the surface illumination light source which is the 6th Example of this invention. この発明の第７の実施例である面照明光源の要部の配置状態を示す断面図である。It is sectional drawing which shows the arrangement | positioning state of the principal part of the surface illumination light source which is the 7th Example of this invention. この発明の第８の実施例である面照明光源に用いられる輝度補正回路の電気的構成を示す回路図である。It is a circuit diagram which shows the electrical constitution of the brightness correction circuit used for the surface illumination light source which is the 8th Example of this invention. 特許文献１に記載された照明装置の要部の電気的構成を示す図である。It is a figure which shows the electrical constitution of the principal part of the illuminating device described in patent document 1. FIG. 図１２の照明装置の動作を説明する図である。It is a figure explaining operation | movement of the illuminating device of FIG. 従来のＬＥＤバックライトの一構成例を示す図である。It is a figure which shows one structural example of the conventional LED backlight. 特許文献２に記載されたバックライトのＬＥＤの配線構成を示す図である。It is a figure which shows the wiring structure of LED of the backlight described in patent document 2. FIG. 特許文献２に記載されたバックライトのＬＥＤの他の配線構成を示す図である。It is a figure which shows the other wiring structure of LED of the backlight described in patent document 2. FIG. 図１５又は図１６中のＬＥＤ５１が設けられたバックライトの断面図である。It is sectional drawing of the backlight in which LED51 in FIG. 15 or FIG. 16 was provided. 図１５又は図１６中のＬＥＤ５１の輝度特性を補正する補正回路の構成を示すブロック図である。It is a block diagram which shows the structure of the correction circuit which correct | amends the luminance characteristic of LED51 in FIG. 15 or FIG.

符号の説明Explanation of symbols

７１ ＬＥＤ（発光素子）
７２ ホトダイオード（受光素子）
７３，７３Ａ ＬＥＤ駆動／補正回路（駆動／補正回路の一部）
７４ 駆動／検出回路（駆動／補正回路の一部）
７６ パッケージ
７８ 補正素子（駆動／補正回路の一部）
Ｖ1 輝度設定電圧（輝度の目標値）
Ｖ2 輝度検出電圧（輝度検出信号）
71 LED (light emitting element)
72 Photodiode (light receiving element)
73, 73A LED drive / correction circuit (part of the drive / correction circuit)
74 Drive / detection circuit (part of drive / correction circuit)
76 Package 78 Correction element (part of drive / correction circuit)
V1 brightness setting voltage (target value of brightness)
V2 luminance detection voltage (luminance detection signal)

Claims (7)

複数の発光素子が面状に配列されてなり、透過型の表示パネルの表示領域に対して背面から照明光を入射させる面照明光源であって、
前記各発光素子毎に輝度を所定の目標値に設定すると共に、前記各発光素子について、その点灯時の輝度の前記目標値からのずれ量を検出し、検出された該ずれ量に基づいて前記輝度を前記目標値に一致させる輝度補正回路が設けられていることを特徴とする面照明光源。 A surface illumination light source in which a plurality of light emitting elements are arranged in a plane shape, and illumination light is incident on the display area of a transmissive display panel from the back,
The luminance is set to a predetermined target value for each of the light emitting elements, and a deviation amount of the luminance at the time of lighting from the target value is detected for each of the light emitting elements, and based on the detected deviation amount, A surface illumination light source characterized in that a luminance correction circuit for matching the luminance with the target value is provided. 前記輝度補正回路は、
前記複数の発光素子に対して１対１で設けられ、前記各発光素子から放射される光を受光し、その輝度に対応したレベルの輝度検出信号を生成する複数の受光素子と、
前記複数の発光素子に対して１対１で設けられ、前記各発光素子に対して駆動用電力を供給すると共に、前記輝度検出信号のレベルに基づいて当該発光素子の前記輝度の各目標値に対する偏差を検出し、該偏差を補償するように前記駆動用電力を補正する駆動／補正回路とから構成されていることを特徴とする請求項１記載の面照明光源。 The brightness correction circuit includes:
A plurality of light receiving elements that are provided one-to-one with respect to the plurality of light emitting elements, receive light emitted from each of the light emitting elements, and generate a luminance detection signal of a level corresponding to the luminance;
The plurality of light emitting elements are provided on a one-to-one basis, supplying driving power to the light emitting elements, and for each target value of the luminance of the light emitting elements based on the level of the luminance detection signal. 2. The surface illumination light source according to claim 1, comprising a drive / correction circuit that detects a deviation and corrects the driving power so as to compensate for the deviation. 前記各発光素子と前記各受光素子とが１対１で近接配置されていることを特徴とする請求項２記載の面照明光源。   3. The surface illumination light source according to claim 2, wherein the light emitting elements and the light receiving elements are arranged close to each other in a one-to-one relationship. 前記各発光素子と前記各受光素子とが同一のパッケージに搭載されていることを特徴とする請求項３記載の面照明光源。   4. The surface illumination light source according to claim 3, wherein each light emitting element and each light receiving element are mounted in the same package. 複数の発光素子が面状に配列されてなり、透過型の表示パネルの表示領域に対して背面から照明光を入射させる面照明光源に用いられ、
前記各発光素子毎に輝度を所定の目標値に設定すると共に、前記各発光素子について、その点灯時の輝度の前記目標値からのずれ量を検出し、検出された該ずれ量に基づいて前記輝度を前記目標値に一致させる構成とされていることを特徴とする輝度補正回路。 A plurality of light emitting elements are arranged in a planar shape, and are used as a surface illumination light source for making illumination light incident on the display area of a transmissive display panel from the back,
The luminance is set to a predetermined target value for each of the light emitting elements, and a deviation amount of the luminance at the time of lighting from the target value is detected for each of the light emitting elements, and based on the detected deviation amount, A luminance correction circuit characterized in that luminance is made to coincide with the target value. 前記複数の発光素子に対して１対１で設けられ、前記各発光素子から放射される光を受光し、その輝度に対応したレベルの輝度検出信号を生成する複数の受光素子と、
前記複数の発光素子に対して１対１で設けられ、前記各発光素子に対して駆動用電力を供給すると共に、前記輝度検出信号のレベルに基づいて当該発光素子の前記輝度の各目標値に対する偏差を検出し、該偏差を補償するように前記駆動用電力を補正する駆動／補正回路とから構成されていることを特徴とする請求項５記載の輝度補正回路。 A plurality of light receiving elements that are provided one-to-one with respect to the plurality of light emitting elements, receive light emitted from each of the light emitting elements, and generate a luminance detection signal of a level corresponding to the luminance;
The plurality of light emitting elements are provided on a one-to-one basis, supplying driving power to the light emitting elements, and for each target value of the luminance of the light emitting elements based on the level of the luminance detection signal. 6. The luminance correction circuit according to claim 5, further comprising a drive / correction circuit that detects a deviation and corrects the driving power so as to compensate for the deviation. 複数の発光素子が面状に配列されてなり、透過型の表示パネルの表示領域に対して背面から照明光を入射させる面照明光源に用いられ、
前記各発光素子毎に輝度を所定の目標値に設定すると共に、前記各発光素子について、その点灯時の輝度の前記目標値からのずれ量を検出し、検出された該ずれ量に基づいて前記輝度を前記目標値に一致させることを特徴とする輝度補正方法。
A plurality of light emitting elements are arranged in a planar shape, and are used as a surface illumination light source for making illumination light incident on the display area of a transmissive display panel from the back,
The luminance is set to a predetermined target value for each of the light emitting elements, and a deviation amount of the luminance at the time of lighting from the target value is detected for each of the light emitting elements, and based on the detected deviation amount, A luminance correction method characterized by matching luminance with the target value.
JP2005337871A 2005-11-22 2005-11-22 Surface lighting light source, luminance correction circuit and luminance correction method used for surface lighting light source Withdrawn JP2007141799A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
JP2005337871A JP2007141799A (en) 2005-11-22 2005-11-22 Surface lighting light source, luminance correction circuit and luminance correction method used for surface lighting light source
US11/592,289 US20070115685A1 (en) 2005-11-22 2006-11-03 Flat lighting source, luminance correcting circuit, luminance correcting method and liquid crystal display
KR1020060112670A KR100854192B1 (en) 2005-11-22 2006-11-15 Flat lighting source, luminance correcting circuit, luminance correcting method and liquid crystal display
TW095142426A TW200727047A (en) 2005-11-22 2006-11-16 Flat lighting source, luminance correcting circuit, luminance correcting method and liquid crystal display
CNA2006101624188A CN1971367A (en) 2005-11-22 2006-11-22 Flat lighting source, luminance correcting circuit, luminance correcting method and liquid crystal display

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2005337871A JP2007141799A (en) 2005-11-22 2005-11-22 Surface lighting light source, luminance correction circuit and luminance correction method used for surface lighting light source

Publications (1)

Publication Number Publication Date
JP2007141799A true JP2007141799A (en) 2007-06-07

Family

ID=38053258

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2005337871A Withdrawn JP2007141799A (en) 2005-11-22 2005-11-22 Surface lighting light source, luminance correction circuit and luminance correction method used for surface lighting light source

Country Status (5)

Country Link
US (1) US20070115685A1 (en)
JP (1) JP2007141799A (en)
KR (1) KR100854192B1 (en)
CN (1) CN1971367A (en)
TW (1) TW200727047A (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009026759A (en) * 2007-07-19 2009-02-05 Aussmak Optoelectronic Corp Light emitting device, and correcting method and control method thereof
JP2009289515A (en) * 2008-05-28 2009-12-10 Iwasaki Electric Co Ltd Surface lighting system, and light-emitting unit
KR101101250B1 (en) * 2011-06-16 2012-01-04 버스텍 주식회사 Led display apparatus for improving character ununiformity in led array and therefor display control method
JP2013519204A (en) * 2010-02-02 2013-05-23 サムグァン インダストリアル エレクトリック カンパニー リミテッド LED module power supply converter for constant output

Families Citing this family (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7878698B2 (en) * 2005-09-28 2011-02-01 Sharp Kabushiki Kaisha Backlight unit and liquid crystal display device
JP2008268642A (en) * 2007-04-23 2008-11-06 Sony Corp Backlight device, method for controlling backlight and liquid crystal display device
CN100462780C (en) * 2007-07-31 2009-02-18 友达光电股份有限公司 Display panel, photoelectric device containing same and drive method and manufacture method
KR100907417B1 (en) * 2007-08-08 2009-07-10 삼성에스디아이 주식회사 Electron emission device for back light unit and liquid crystal display thereof
KR101450143B1 (en) * 2007-10-25 2014-10-14 삼성디스플레이 주식회사 Timing controller, liquid crystal display comprising the same and driving method of liquid crystal display
US20100007588A1 (en) * 2008-07-09 2010-01-14 Adaptive Micro Systems Llc System and method for led degradation and temperature compensation
US20100109562A1 (en) * 2008-11-06 2010-05-06 StarChips Technology Inc. Backlight module and light-emitting device thereof
KR101577223B1 (en) * 2009-06-03 2015-12-15 엘지디스플레이 주식회사 Liquid crystal display device
CN102714904A (en) * 2009-10-14 2012-10-03 惠普发展公司，有限责任合伙企业 Stabilized light source having luminance feedback control
CN101697273B (en) * 2009-10-29 2012-09-19 彩虹集团公司 LCD luminance uniformity automatic correcting system and method for LED backlight
CN102136255B (en) * 2010-01-27 2012-12-26 京东方科技集团股份有限公司 Method and device for compensating colors of backlight
JP2012004190A (en) * 2010-06-14 2012-01-05 Toshiba Corp Led driving device
TWI455578B (en) 2011-02-08 2014-10-01 Alpha Networks Inc Monitoring camera and operation method
CN104157237B (en) * 2014-07-18 2016-05-11 京东方科技集团股份有限公司 A kind of display driver circuit and driving method thereof, display unit
US10072830B2 (en) * 2016-05-06 2018-09-11 Hung Lin Uniform luminance light-emitting diode circuit board
CN105976767B (en) * 2016-06-28 2019-06-21 凌云光技术集团有限责任公司 A kind of area source brightness uniformity adjusting method, apparatus and system
CN107863065A (en) * 2017-11-24 2018-03-30 京东方科技集团股份有限公司 Pixel unit circuit, driving method and image element circuit
CN109239980A (en) * 2018-11-28 2019-01-18 厦门天马微电子有限公司 Backlight assembly and display device
JP7303047B2 (en) * 2019-06-27 2023-07-04 矢崎総業株式会社 Light-emitting device and chromaticity variation correction method
CN113075525B (en) * 2021-04-14 2022-03-22 东莞市谷麦光学科技有限公司 Voltage correction method for LED light splitting station

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE69825402T2 (en) * 1997-03-12 2005-08-04 Seiko Epson Corp. PIXEL CIRCUIT, DISPLAY DEVICE AND ELECTRONIC APPARATUS WITH POWER-CONTROLLED LIGHT-EMITTING DEVICE
US6774578B2 (en) * 2000-09-19 2004-08-10 Semiconductor Energy Laboratory Co., Ltd. Self light emitting device and method of driving thereof
US6720942B2 (en) * 2002-02-12 2004-04-13 Eastman Kodak Company Flat-panel light emitting pixel with luminance feedback
GB2389951A (en) * 2002-06-18 2003-12-24 Cambridge Display Tech Ltd Display driver circuits for active matrix OLED displays
US7184009B2 (en) * 2002-06-21 2007-02-27 Nokia Corporation Display circuit with optical sensor
US7294816B2 (en) * 2003-12-19 2007-11-13 Avago Technologies Ecbu Ip (Singapore) Pte. Ltd. LED illumination system having an intensity monitoring system

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009026759A (en) * 2007-07-19 2009-02-05 Aussmak Optoelectronic Corp Light emitting device, and correcting method and control method thereof
JP2009289515A (en) * 2008-05-28 2009-12-10 Iwasaki Electric Co Ltd Surface lighting system, and light-emitting unit
JP2013519204A (en) * 2010-02-02 2013-05-23 サムグァン インダストリアル エレクトリック カンパニー リミテッド LED module power supply converter for constant output
KR101101250B1 (en) * 2011-06-16 2012-01-04 버스텍 주식회사 Led display apparatus for improving character ununiformity in led array and therefor display control method

Also Published As

Publication number Publication date
CN1971367A (en) 2007-05-30
TW200727047A (en) 2007-07-16
US20070115685A1 (en) 2007-05-24
KR100854192B1 (en) 2008-08-26
KR20070054101A (en) 2007-05-28

Similar Documents

Publication Publication Date Title
JP2007141799A (en) Surface lighting light source, luminance correction circuit and luminance correction method used for surface lighting light source
JP4757585B2 (en) Light source unit and lighting device
US7696964B2 (en) LED backlight for LCD with color uniformity recalibration over lifetime
JP5071834B2 (en) Lighting device and adjustment method
TWI438742B (en) Light emitting device and method for driving the same
US7872621B2 (en) Color LED driver
US8120276B2 (en) Light source emitting mixed-colored light and method for controlling the color locus of such a light source
JP4182930B2 (en) Display device and backlight device
JP4891606B2 (en) Backlight unit and liquid crystal display device using the same
JP2006171693A (en) Backlight device, method of driving backlight, and liquid crystal display apparatus
JP2010237683A (en) Backlight apparatus, method of driving backlight and liquid crystal display apparatus
JP2007165632A (en) Led backlight apparatus and image display device
US20100253613A1 (en) Led backlight and electronic control
KR20090094143A (en) Led module with dedicated colour regulation and corresponding method
US20100117941A1 (en) Color-controlled backlit display device
JP4988525B2 (en) Light-emitting diode luminaire
CN101742769B (en) Method for driving light emitting diode, and display apparatus having back light assembly
KR101607126B1 (en) Back light unit
KR20150011251A (en) Circuit and method for driving backlight and liquid crystal display device including the same
JP7043277B2 (en) Light source module and backlight device
JP2011009117A (en) Light-emitting device and control method of the same

Legal Events

Date Code Title Description
A621 Written request for application examination

Free format text: JAPANESE INTERMEDIATE CODE: A621

Effective date: 20081016

A761 Written withdrawal of application

Free format text: JAPANESE INTERMEDIATE CODE: A761

Effective date: 20100823