JPH11223805A - Lighting system - Google Patents
Lighting systemInfo
- Publication number
- JPH11223805A JPH11223805A JP10027607A JP2760798A JPH11223805A JP H11223805 A JPH11223805 A JP H11223805A JP 10027607 A JP10027607 A JP 10027607A JP 2760798 A JP2760798 A JP 2760798A JP H11223805 A JPH11223805 A JP H11223805A
- Authority
- JP
- Japan
- Prior art keywords
- light
- white
- liquid crystal
- backlight
- light emission
- 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.)
- Granted
Links
Landscapes
- Liquid Crystal (AREA)
- Light Guides In General And Applications Therefor (AREA)
- Planar Illumination Modules (AREA)
- Devices For Indicating Variable Information By Combining Individual Elements (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、透過型液晶表示パ
ネルの背面から白色ＬＥＤを用いたバックライトからの
照明光を照射して、前記透過型液晶表示パネルを照明す
る照明装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illuminating device for illuminating a transmission type liquid crystal display panel by irradiating illumination light from a backlight using white LEDs from the back of the transmission type liquid crystal display panel.
【０００２】[0002]
【従来の技術】ＯＡ機器、ビデオカメラ、携帯電話など
の電子機器には、文字図形などの画像情報を表示する液
晶表示パネルが設けられ、この液晶パネルは、背面から
導光板と導光板の端面に配設された光源からなるバック
ライトにより照明されるようになっている。バックライ
トの光源としては、従来小型の蛍光ランプが使用されて
いたが、近年高輝度の白色ＬＥＤが開発され、導光板の
端面に複数の白色ＬＥＤを配設したバックライトが使用
されるようになっている。2. Description of the Related Art Electronic equipment such as OA equipment, video cameras, and mobile phones are provided with a liquid crystal display panel for displaying image information such as text and graphics. Illuminated by a backlight comprising a light source disposed in Conventionally, small fluorescent lamps have been used as the light source of the backlight. Recently, high-luminance white LEDs have been developed, and backlights in which a plurality of white LEDs are arranged on the end face of a light guide plate have been used. Has become.
【０００３】従来の白色ＬＥＤを使用したバックライト
による照明装置では、図５に示すように、液晶表示パネ
ル１の背面において、駆動端子ｔ２とアース間に、抵抗
２６と白色ＬＥＤ２５ａの直列接続回路、抵抗２６と白
色ＬＥＤ２５ｂの直列接続回路・・・抵抗２６と白色Ｌ
ＥＤ２５ｎの直列接続回路が互いに並列に接続された発
光源を有するバックライト２７が配置されている。この
バックライト２７の駆動端子ｔ２が、スイッチング動作
を行なうトランジスタ２５のコレクタに接続され、この
トランジスタ２５のベースには、トランジスタ２５にＯ
Ｎ動作を行なわせるコントロール信号Ｆｃを出力するコ
ントローラ２４が接続され、トランジスタ２５のエミッ
タには、駆動信号Ｆｌが印加される電源端子ｔ１が接続
されている。In a conventional lighting device using a backlight using white LEDs, as shown in FIG. 5, a series connection circuit of a resistor 26 and a white LED 25a is provided between a drive terminal t2 and ground on the back of the liquid crystal display panel 1. Series connection circuit of resistor 26 and white LED 25b: resistor 26 and white L
A backlight 27 having a light emitting source in which a series connection circuit of the ED 25n is connected in parallel with each other is arranged. The drive terminal t2 of the backlight 27 is connected to the collector of a transistor 25 that performs a switching operation.
A controller 24 for outputting a control signal Fc for performing N operation is connected, and a power supply terminal t1 to which a drive signal Fl is applied is connected to an emitter of the transistor 25.
【０００４】この従来の照明装置では、コントローラ２
４から、図６（ａ）に示すように、所定のバルス幅ｄの
コントロール信号Ｆｃが、一定の繰り返し間隔Ｄで出力
され、このコントロール信号Ｆｃの印加の区間において
トランジスタ２５が０Ｎ状態となり、駆動信号Ｆｌが、
図６（ｂ）に示すように、バックライト２７の駆動端子
ｔ２に、一定の繰り返し間隔Ｄで印加され、白色ＬＥＤ
２５ａ〜２５ｎに電流が流れて、白色ＬＥＤ２５ａ〜２
５ｎが線状に発光し、バックライト２７からの照明光が
液晶表示パネル１を背面から照明する。In this conventional lighting device, the controller 2
4, as shown in FIG. 6A, a control signal Fc having a predetermined pulse width d is output at a constant repetition interval D, and during the application period of the control signal Fc, the transistor 25 enters the 0N state, and The signal Fl is
As shown in FIG. 6B, a white LED is applied to the drive terminal t2 of the backlight 27 at a constant repetition interval D.
When current flows through the white LEDs 25a to 25n, the white LEDs 25a to 25n
5n emits light linearly, and the illumination light from the backlight 27 illuminates the liquid crystal display panel 1 from the back.
【０００５】[0005]
【発明が解決しようとする課題】前述の従来の照明装置
では、各白色ＬＥＤに流れる電流をＬｍａとすると、バ
ックライト２７の駆動端子には、トランジスタ２５のベ
ースへのコントロール信号Ｆｃの印加時に、比較的大き
なｎＬｍａの電流が、パルス幅ｄに対応して流れる。こ
のために、バックライト２７の駆動端子に流れるｎＬｍ
ａの電流の立ち上がり縁部では、オーバーシュート波形
が発生し、電流の立ち下がり縁部では、アンダーシュー
ト波形が発生する。このオーバーシュート波形とアンダ
ーシュート波形とは、ノイズとなって照明装置が組み込
まれているビデオカメラなどの電子機器に侵入し、例え
ばカメラ部のＣＣＤの動作にノイズの悪影響を及ぼすお
それがある。In the above-mentioned conventional lighting device, assuming that the current flowing through each white LED is Lma, the drive terminal of the backlight 27 receives the control signal Fc applied to the base of the transistor 25 when the control signal Fc is applied to the base of the transistor 25. A relatively large current of nLma flows corresponding to the pulse width d. For this reason, nLm flowing to the drive terminal of the backlight 27
At the rising edge of the current a, an overshoot waveform occurs, and at the falling edge of the current, an undershoot waveform occurs. The overshoot waveform and the undershoot waveform may become noise and penetrate into an electronic device such as a video camera in which the lighting device is incorporated, and may adversely affect, for example, the operation of the CCD in the camera unit.
【０００６】また、従来の照明装置では、バックライト
２７が、コントロール信号Ｆｃによって、間隔Ｄをもっ
て繰り返し０Ｎ制御され、トランジスタ２５ａ〜２５ｎ
が間歇的に発光制御されるので、輝度の低下やばらつき
が発生するという問題もあった。Further, in the conventional lighting device, the backlight 27 is repeatedly controlled by the control signal Fc at 0N with an interval D, and the transistors 25a to 25n are controlled.
Since the light emission is intermittently controlled, there is a problem that the brightness is reduced or the brightness is varied.
【０００７】本発明は、前述したような従来のこの種の
照明装置の動作の現状に鑑みてなされたものであり、そ
の目的は、バックライトに流れる電流に基づくノイズの
悪影響を低減することが可能で、且つ安定した輝度の白
色光を照明光として出力することが可能な照明装置を提
供することにある。SUMMARY OF THE INVENTION The present invention has been made in view of the current state of operation of this type of conventional illumination device as described above, and has as its object to reduce the adverse effects of noise due to the current flowing through the backlight. It is an object of the present invention to provide a lighting device capable of outputting white light having a stable luminance as illumination light.
【０００８】[0008]
【課題を解決するための手段】前記目的を達成するため
に、本発明は、透過型液晶表示パネルの背面から照明光
を照射して、前記透過型液晶表示パネルを照明する照明
装置であり、互いに並列に接続された複数個の白色ＬＥ
Ｄからなる発光源の複数組で構成され、前記透過型液晶
表示パネルに背面から照明光を照射するバックライト
と、前記複数組の発光源に、位相を順次ずらして駆動パ
ルス信号を印加する発光制御手段とを有することを特徴
とするものである。In order to achieve the above object, the present invention is directed to an illuminating device for illuminating the transmissive liquid crystal display panel by irradiating illumination light from the back of the transmissive liquid crystal display panel, A plurality of white LEs connected in parallel with each other
A backlight configured to irradiate illumination light from the back to the transmissive liquid crystal display panel; and a light emission configured to sequentially apply a drive pulse signal to the plurality of sets of light sources, the phases being sequentially shifted. And control means.
【０００９】[0009]
【発明の実施の形態】以下に、本発明の一実施の形態
を、図１ないし図４を参照して説明する。図１は本実施
の形態の要部の外観構成を示す説明図、図２は本実施の
形態に使用される白色ＬＥＤの構成を示す説明図、図３
は本実施の構成の要部の構成を示すブロック図、図４は
本実施の形態の動作を示す信号波形図である。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is an explanatory diagram showing an external configuration of a main part of the present embodiment. FIG. 2 is an explanatory diagram showing a configuration of a white LED used in the present embodiment.
Is a block diagram showing a configuration of a main part of the present embodiment, and FIG. 4 is a signal waveform diagram showing an operation of the present embodiment.
【００１０】本実施の形態では、図１に示すように、液
晶表示パネル１の背面に対接して、シリコンなどの導光
材で形成された集光板１０が配設され、この集光板１０
の下端面に対接して、複数の白色ＬＥＤ７からなるバッ
クライトが収容されたアクリル材のボデイ１１が配設さ
れ、このボデイ１１に、バックライトの動作を制御する
制御ユニット３０が取り付けられている。液晶表示パネ
ル１は、ＩＴＯ膜などにより透明電極がパタン形成され
た二枚の透明基板間に、画像を形成する液晶がシール材
に囲まれて封止されており、集光板１０のボデイ１１と
の対接面には、酸化チタンなどの白色物質の印刷により
光拡散面１０ａが形成されている。In the present embodiment, as shown in FIG. 1, a light collector 10 made of a light guide material such as silicon is provided in contact with the back surface of the liquid crystal display panel 1, and
A body 11 made of an acrylic material accommodating a backlight made up of a plurality of white LEDs 7 is provided in contact with the lower end surface of the body 11, and a control unit 30 for controlling the operation of the backlight is attached to the body 11. . The liquid crystal display panel 1 has a structure in which a liquid crystal for forming an image is sealed between two transparent substrates on which transparent electrodes are formed with an ITO film or the like by a sealing material. The light diffusing surface 10a is formed by printing a white substance such as titanium oxide on the contact surface of.
【００１１】本実施の形態で使用される白色ＬＥＤ７
は、図２に示すような構成になっていて、回路基板１５
に搭載装着された基体１３に、青色光を放射するチップ
１２が取り付けられ、このチップ１２は蛍光体層１４で
覆われており、チップ１２に電力を供給する導体部１６
が、回路基板１５に形成された電源供給端子１７に接続
されている。この白色ＬＥＤ７では、チップ１２から発
光される高輝度な青色光は、蛍光体層１４内で何回かの
吸収と散乱とを繰り返した後に外部に放出されるが、蛍
光体層１４に吸収された青色光を励起源として、蛍光体
層１４からは黄色の蛍光が外部に放出され、放出される
青色光と黄色光とが混合されて、外部からは、白色ＬＥ
Ｄ７が白色の光を放出すると見做されるように構成され
ている。[0011] White LED 7 used in the present embodiment
Is configured as shown in FIG.
A chip 12 that emits blue light is attached to a base 13 mounted on the chip 12. The chip 12 is covered with a phosphor layer 14, and a conductor 16 that supplies power to the chip 12 is provided.
Are connected to a power supply terminal 17 formed on the circuit board 15. In this white LED 7, high-luminance blue light emitted from the chip 12 is emitted to the outside after repeating absorption and scattering several times in the phosphor layer 14, but is absorbed by the phosphor layer 14. Using the blue light as an excitation source, yellow fluorescent light is emitted from the phosphor layer 14 to the outside, the emitted blue light and yellow light are mixed, and the white LE is emitted from the outside.
D7 is configured to emit white light.
【００１２】本実施の形態では、図３に示すように、液
晶表示パネル１を背面から照明するバックライト２７Ａ
が、それぞれｍ個の白色ＬＥＤからなる発光源の３組で
構成された場合であり、第１の発光源は、駆動端子ｔ２
とアース間に、抵抗３と白色ＬＥＤ７ａの直列接続回
路、抵抗３と白色ＬＥＤ７ｂの直列接続回路・・・抵抗
３と白色ＬＥＤ７ｍの直列接続回路が、互いに並列に接
続された構成となっている。同様にして、第２の発光源
は、駆動端子ｔ３とアース間に、抵抗３と白色ＬＥＤ８
ａの直列接続回路、抵抗３と白色ＬＥＤ８ｂの直列接続
回路・・・抵抗３と白色ＬＥＤ８ｍの直列接続回路が、
互いに並列に接続された構成となっており、第３の発光
源は、駆動端子ｔ４とアース間に、抵抗３と白色ＬＥＤ
９ａの直列接続回路、抵抗３と白色ＬＥＤ９ｂの直列接
続回路・・・抵抗３と白色ＬＥＤ９ｍの直列接続回路
が、互いに並列に接続された構成となっている。In this embodiment, as shown in FIG. 3, a backlight 27A for illuminating the liquid crystal display panel 1 from the back is provided.
Is a case in which three sets of light emitting sources each including m white LEDs are provided, and the first light emitting source is a driving terminal t2
In this configuration, a series connection circuit of the resistor 3 and the white LED 7a, a series connection circuit of the resistor 3 and the white LED 7b ... a series connection circuit of the resistor 3 and the white LED 7m are connected in parallel with each other. Similarly, the second light emitting source is connected between the driving terminal t3 and the ground, the resistor 3 and the white LED 8 are connected.
a series connection circuit of a, a series connection circuit of the resistor 3 and the white LED 8b ... a series connection circuit of the resistor 3 and the white LED 8m,
The third light emitting source is connected between the driving terminal t4 and the ground, and the resistor 3 and the white LED are connected to each other.
9a, a series connection circuit of the resistor 3 and the white LED 9b ... a series connection circuit of the resistor 3 and the white LED 9m are connected in parallel to each other.
【００１３】このバックライト２７Ａを発光制御する制
御ユニット３０には、互いに位相をずらしたコントロー
ル信号Ｆｃ１、Ｆｃ２、Ｆｃ３を順次出力するコントロ
ーラ２と、第１の発光源の発光をＯＮ−ＯＦＦ制御する
トランジスタ１８、第２の発光源の発光をＯＮ−ＯＦＦ
制御するトランジスタ１９、第３の発光源の発光をＯＮ
−ＯＦＦ制御するトランジスタ２０が設けられている。
そして、駆動信号Ｆｌが印加される電源端子ｔ１が、ト
ランジスタ１８、１９、２０のエミッタにそれぞれ接続
され、トランジスタ１８、１９、２０のコレクタは、第
１の発光源の駆動端子ｔ２、第２の発光源の駆動端子ｔ
３、第３の発光源の駆動端子ｔ４にそれぞれ接続され、
コントローラ２から出力されるコントロール信号Ｆｃ
１、Ｆｃ２、Ｆｃ３が、それぞれ抵抗２１、２２、２３
を介して、トランジスタ１８、１９、２０のベースに印
加されるように構成されている。The control unit 30 for controlling the light emission of the backlight 27A includes a controller 2 for sequentially outputting control signals Fc1, Fc2, and Fc3 whose phases are shifted from each other, and ON-OFF control of the light emission of the first light emitting source. Turns on / off the light emission of the transistor 18 and the second light emitting source
Controlling transistor 19, turning on light emission of third light emitting source
A transistor 20 for performing -OFF control is provided.
The power supply terminal t1 to which the drive signal Fl is applied is connected to the emitters of the transistors 18, 19 and 20, respectively. The collectors of the transistors 18, 19 and 20 are connected to the drive terminal t2 of the first light emitting source and the second Drive terminal t of the light emitting source
3, connected to the drive terminal t4 of the third light emitting source,
Control signal Fc output from controller 2
1, Fc2 and Fc3 are resistors 21, 22, and 23, respectively.
Is applied to the bases of the transistors 18, 19, 20.
【００１４】また、コントローラ２から出力されるコン
トロール信号Ｆｃ１、Ｆｃ２、Ｆｃ３は、図４に示すよ
うに、パルス幅がｄに設定され、コントロール信号Ｆｃ
１の後縁部に、コントロール信号Ｆｃ２の前縁部が位置
し、コントロール信号Ｆｃ２の後縁部に、コントロール
信号Ｆｃ３の前縁部が位置し、この状態が繰り返され
て、コントローラ２によって、コントロール信号Ｆｃ
１、Ｆｃ２、Ｆｃ３が互いに連続して出力されるように
制御されている。The control signals Fc1, Fc2 and Fc3 output from the controller 2 have a pulse width of d as shown in FIG.
1, the leading edge of the control signal Fc2 is located at the trailing edge, and the leading edge of the control signal Fc3 is located at the trailing edge of the control signal Fc2. This state is repeated. Signal Fc
1, Fc2 and Fc3 are controlled so as to be continuously output.
【００１５】このような構成の本実施の形態の動作を説
明する。本実施の形態では、電源端子ｔ１に駆動信号Ｆ
ｌが印加され、コントローラ２からコントロール信号Ｆ
ｃ１、Ｆｃ２、Ｆｃ３が順次出力されると、先ず、コン
トロール信号Ｆｃ１のパルス幅ｄの区間で、トランジス
タ１８がＯＮとなり、トランジスタ１８のコレクタか
ら、駆動端子ｔ２に駆動信号Ｆｌが印加され、白色ＬＥ
Ｄ７ａ、７ｂ、７ｃ・・・７ｍに電流が流れ、白色ＬＥ
Ｄ７ａ〜７ｍが発光し、バックライト２７Ａの第１の発
光源からの白色光で、液晶表示パネル１が照明される。The operation of the embodiment having such a configuration will be described. In the present embodiment, the drive signal F is supplied to the power supply terminal t1.
1 is applied, and the control signal F
When c1, Fc2, and Fc3 are sequentially output, first, the transistor 18 is turned on in the section of the pulse width d of the control signal Fc1, and the drive signal Fl is applied from the collector of the transistor 18 to the drive terminal t2, and the white LE
D7a, 7b, 7c... 7m cause current to flow, and white LE
D7a to 7m emit light, and the liquid crystal display panel 1 is illuminated with white light from the first light source of the backlight 27A.
【００１６】次いで、コントロール信号Ｆｃ１の後縁部
に連続して前縁部が位置して、コントローラ２から出力
されるコントロール信号Ｆｃ２のパルス幅ｄの区間で、
トランジスタ１９がＯＮとなり、トランジスタ１９のコ
レクタから、駆動端子ｔ３に駆動信号Ｆｌが印加され、
白色ＬＥＤ８ａ、８ｂ、８ｃ・・・８ｍに電流が流れ、
白色ＬＥＤ８ａ〜８ｍが発光し、バックライト２７Ａの
第２の発光源からの白色光で、液晶表示パネル１が照明
される。Next, the leading edge portion is located continuously to the trailing edge portion of the control signal Fc1, and in the section of the pulse width d of the control signal Fc2 output from the controller 2,
The transistor 19 is turned on, and a drive signal Fl is applied from the collector of the transistor 19 to the drive terminal t3,
A current flows through the white LEDs 8a, 8b, 8c,.
The white LEDs 8a to 8m emit light, and the liquid crystal display panel 1 is illuminated with white light from the second light source of the backlight 27A.
【００１７】そして、コントロール信号Ｆｃ２の後縁部
に連続して前縁部が位置して、コントローラ２から出力
されるコントロール信号Ｆｃ３のパルス幅ｄの区間で、
トランジスタ２０がＯＮとなり、トランジスタ２０のコ
レクタから、駆動端子ｔ４に駆動信号Ｆｌが印加され、
白色ＬＥＤ９ａ、９ｂ、９ｃ・・・９ｍに電流が流れ、
白色ＬＥＤ９ａ〜９ｍが発光し、バックライト２７Ａの
第３の発光源からの白色光で、液晶表示パネル１が照明
される。The leading edge is positioned continuously to the trailing edge of the control signal Fc2, and the pulse width d of the control signal Fc3 output from the controller 2 is
The transistor 20 is turned on, and a drive signal Fl is applied from the collector of the transistor 20 to the drive terminal t4,
A current flows through the white LEDs 9a, 9b, 9c,.
The white LEDs 9a to 9m emit light, and the liquid crystal display panel 1 is illuminated with white light from the third light source of the backlight 27A.
【００１８】以下、同様にして、バックライト２７Ａの
第１の発光源、第２の発光源及び第３の発光源が、コン
トロール信号Ｆｃ１、Ｆｃ２、Ｆｃ３によって、順次繰
り返して発光制御され、バックライト２７Ａにおいて
は、第１の発光源、第２の発光源及び第３の発光源から
の白色光が、順次連続して発光され、バックライト２７
Ａからは、常に所定の輝度の白色照明光が、液晶表示パ
ネル１に照明光として照射される。Hereinafter, similarly, the first light source, the second light source, and the third light source of the backlight 27A are sequentially and repeatedly controlled to emit light by the control signals Fc1, Fc2, and Fc3. In 27A, the white light from the first light source, the second light source, and the third light source is emitted continuously and sequentially, and
From A, white illumination light of a predetermined luminance is always applied to the liquid crystal display panel 1 as illumination light.
【００１９】この場合、バックライト２７Ａに収容され
ている白色ＬＥＤの全数は３ｍ個であり、各白色ＬＥＤ
の負荷電流をＩｍＡとして、すでに説明した従来の照明
装置のように、全ての白色ＬＥＤに同時に電流を供給す
ると、バックライト２７Ａには、瞬時に３ｍＩｍＡの電
流が流れるが、本実施の形態では、バックライト２７Ａ
に瞬時に流れる電流はｍＩｍＡに減少されている。この
ために、本実施の形態によると、バックライト２７Ａに
流れる電流により発生するノイズを低減することが可能
になり、このノイズによって、本実施の形態が組み込ま
れる電子機器のブロック、例えばビデオカメラのＣＣＤ
に、ノイズによる悪影響が及ぼされることが防止され
る。In this case, the total number of white LEDs housed in the backlight 27A is 3 m, and each white LED is
When the current is supplied to all the white LEDs at the same time as in the conventional lighting device described above, assuming that the load current is ImA, a current of 3 mImA flows instantaneously to the backlight 27A. In the present embodiment, Backlight 27A
Is instantaneously reduced to mImA. For this reason, according to the present embodiment, it is possible to reduce the noise generated by the current flowing through the backlight 27A, and this noise causes the block of the electronic device in which the present embodiment is incorporated, for example, a video camera. CCD
In addition, adverse effects due to noise are prevented.
【００２０】また、本実施の形態では、所定の位相差を
もって出力されるコントロール信号Ｆｃ１、Ｆｃ２、Ｆ
ｃ３により、バックライト２７Ａの第１の発光源ないし
第３の発光源が、順次連続的に発光制御されるので、従
来の照明装置のような間歇的な制御による輝度の低下や
ばらつきがなく、常に一定輝度の安定した白色光で液晶
パネル１を照明することが可能になる。In this embodiment, the control signals Fc1, Fc2, Fc output with a predetermined phase difference are provided.
Since the first light source to the third light source of the backlight 27A are sequentially and continuously controlled to emit light by c3, there is no decrease or variation in luminance due to intermittent control as in a conventional lighting device. The liquid crystal panel 1 can always be illuminated with stable white light having a constant luminance.
【００２１】[0021]
【発明の効果】本発明によると、互いに並列に接続され
た複数個の白色ＬＥＤからなる発光源の複数組で構成さ
れるバックライトに対して、発光制御手段によって、複
数組の発光源に位相を順次ずらして駆動パルス信号が印
加され、この駆動パルス信号によつて、透過型液晶表示
パネルに背面から照明光が照射されるので、全ての白色
ＬＥＤに流れる全電流値を発光源数で除した電流値の電
流によって、バックライトが連続的に発光し、発光源に
流れる電流に基づくノイズを低減し、照明装置で発生す
るノイズが、照明装置が組み込み使用される電子機器に
及ぼす悪影響を低減することが可能になると共に、バッ
クライトを輝度の低下やばらつきなしに安定に発光させ
ることが可能になる。According to the present invention, with respect to a backlight composed of a plurality of sets of light-emitting sources each composed of a plurality of white LEDs connected in parallel to each other, the light-emission control means controls the phases of the plurality of light-emitting sources. Are sequentially shifted to apply a driving pulse signal. The driving pulse signal irradiates the transmissive liquid crystal display panel with illumination light from the back. Therefore, the total current value flowing through all the white LEDs is divided by the number of light emitting sources. The backlight emits light continuously due to the current value, reducing the noise based on the current flowing to the light emitting source and reducing the adverse effect of the noise generated by the lighting device on the electronic equipment in which the lighting device is embedded and used. In addition, the backlight can be stably emitted without a decrease in brightness or variation.
【図１】本発明の一実施の形態の要部の外観構成を示す
説明図である。FIG. 1 is an explanatory diagram illustrating an external configuration of a main part according to an embodiment of the present invention.
【図２】同実施の形態に使用される白色ＬＥＤの構成を
示す説明図である。FIG. 2 is an explanatory diagram showing a configuration of a white LED used in the embodiment.
【図３】同実施の構成の要部の構成を示すブロック図で
ある。FIG. 3 is a block diagram showing a configuration of a main part of the configuration of the embodiment.
【図４】同実施の形態の動作を示す信号波形図である。FIG. 4 is a signal waveform diagram showing an operation of the embodiment.
【図５】従来の照明装置の構成を示すブロック図であ
る。FIG. 5 is a block diagram illustrating a configuration of a conventional lighting device.
【図６】従来の照明装置の動作を示す信号波形図であ
る。FIG. 6 is a signal waveform diagram illustrating an operation of a conventional lighting device.
１…液晶表示パネル、２…コントローラ、７ａ〜７ｍ，
８ａ〜８ｍ，９ａ〜９ｍ…白色ＬＥＤ、１８，１９，２
０…トランジスタ、２７Ａ…バックライト、３０…制御
ユニット。1: liquid crystal display panel, 2: controller, 7a to 7m,
8a to 8m, 9a to 9m: White LED, 18, 19, 2
0 ... transistor, 27A ... backlight, 30 ... control unit.
Claims (1)
を照射して、前記透過型液晶表示パネルを照明する照明
装置であり、 互いに並列に接続された複数個の白色ＬＥＤからなる発
光源の複数組で構成され、前記透過型液晶表示パネルに
背面から照明光を照射するバックライトと、 前記複数組の発光源に、位相を順次ずらして駆動パルス
信号を印加する発光制御手段とを有することを特徴とす
る照明装置。1. An illumination device for illuminating a transmissive liquid crystal display panel by irradiating illumination light from the back of the transmissive liquid crystal display panel, wherein the light source comprises a plurality of white LEDs connected in parallel with each other. A backlight configured to illuminate the transmissive liquid crystal display panel with illumination light from a back surface; and a light emission control unit configured to apply a drive pulse signal to the plurality of light emitting sources with a phase being sequentially shifted. A lighting device characterized by the above-mentioned.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP02760798A JP3994505B2 (en) | 1998-02-09 | 1998-02-09 | Lighting device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP02760798A JP3994505B2 (en) | 1998-02-09 | 1998-02-09 | Lighting device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH11223805A true JPH11223805A (en) | 1999-08-17 |
| JP3994505B2 JP3994505B2 (en) | 2007-10-24 |
Family
ID=12225624
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP02760798A Expired - Fee Related JP3994505B2 (en) | 1998-02-09 | 1998-02-09 | Lighting device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3994505B2 (en) |
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