WO2007018071A1 - Display device-use lighting system and display device - Google Patents

Display device-use lighting system and display device Download PDF

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Publication number
WO2007018071A1
WO2007018071A1 PCT/JP2006/315185 JP2006315185W WO2007018071A1 WO 2007018071 A1 WO2007018071 A1 WO 2007018071A1 JP 2006315185 W JP2006315185 W JP 2006315185W WO 2007018071 A1 WO2007018071 A1 WO 2007018071A1
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WIPO (PCT)
Prior art keywords
voltage
display device
unit
discharge tubes
power supply
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Application number
PCT/JP2006/315185
Other languages
French (fr)
Japanese (ja)
Inventor
Masayuki Murao
Original Assignee
Sharp Kabushiki Kaisha
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Publication of WO2007018071A1 publication Critical patent/WO2007018071A1/en

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Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
    • H05B41/14—Circuit arrangements
    • H05B41/36—Controlling
    • H05B41/38—Controlling the intensity of light
    • H05B41/39—Controlling the intensity of light continuously
    • H05B41/392—Controlling the intensity of light continuously using semiconductor devices, e.g. thyristor
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
    • H05B41/14—Circuit arrangements
    • H05B41/26—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc
    • H05B41/28—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters
    • H05B41/282—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters with semiconductor devices
    • H05B41/2821—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters with semiconductor devices by means of a single-switch converter or a parallel push-pull converter in the final stage
    • H05B41/2822—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters with semiconductor devices by means of a single-switch converter or a parallel push-pull converter in the final stage using specially adapted components in the load circuit, e.g. feed-back transformers, piezoelectric transformers; using specially adapted load circuit configurations

Definitions

  • the present invention relates to a display device illumination device suitably used for a display device such as a liquid crystal display device.
  • a liquid crystal display device including a liquid crystal display panel generally has an illumination device arranged on the back side of the liquid crystal display panel.
  • This illuminating device is usually provided with a cold cathode discharge tube as a light source, and the characteristics of light emitted from the discharge tube are adjusted to irradiate the back side of the display panel. The irradiated light passes through the display panel, and an image is displayed on the front side of the display panel.
  • FIG. 4 two discharge tubes 7 and 8 are connected at the low pressure sides 7b and 8b, and the high voltage sides 7a and 8a of the respective discharge tubes 7 and 8 are alternately connected from the power supply unit 22.
  • a method of applying high voltages Va and Vb having opposite phases to each other has been proposed (see Japanese Patent Application Laid-Open No. 2002-278471). This eliminates the need for the return line of the discharge tube, thus solving the above problem.
  • a cold cathode discharge tube contains mercury and a rare gas.
  • mercury ions When discharge is started by a sinusoidal voltage, mercury ions are generated and accelerated by the electric field acting between the electrodes, and move to the cathode.
  • the problem to be solved by the present invention is that when a discharge tube is turned on by alternately applying a high voltage of opposite phase to both end electrodes of a series of two discharge tubes, the discharge tube It is an object to provide a display device illumination device and a display device including the same.
  • a display device illumination device is a display device illumination device in which a plurality of discharge tubes are arranged on the back side of a display panel, and N (N is 2 (Integer above)
  • the gist of the invention is that the power supply section force is provided with a feedback control section that adjusts the voltage applied to the high voltage side of the discharge tube according to the voltage generated at the connection section.
  • the feedback control unit is applied to each of the discharge tubes from the voltage detection unit that detects a voltage generated in the low-voltage side coupling unit, and from the power supply unit according to the detected voltage.
  • a correction unit that supplies a signal for adjusting the amplitude and Z or phase difference of at least one of the high voltages of opposite phases to the power supply unit.
  • the voltage detection unit may be configured to include a rectification unit that rectifies the detection voltage. Furthermore, it is preferable that the correction unit is provided with a determination unit that compares and calculates the detected voltage and an arbitrary reference voltage. And it is good to set it as the structure which is a display apparatus provided with such an illuminating device for display apparatuses.
  • a power supply unit that applies a high voltage in the opposite phase to the high voltage side of each discharge tube in which the low voltage sides of at least two discharge tubes are connected, and the discharge A feedback control unit that adjusts the voltage applied from the power supply unit to the high voltage side of the discharge tube according to the voltage generated at the coupling unit connected to the low voltage side of the tube is provided. It is possible to reduce the voltage. This suppresses the difference between the positive and negative amplitudes of the tube voltage and prevents the discharge tube from reaching a short life.
  • the feedback control unit is applied to each of the discharge tubes from the voltage detection unit that detects a voltage generated in the low-voltage side coupling unit and the power supply unit according to the detected voltage. If the configuration includes a correction unit that supplies the power supply unit with a signal for adjusting the amplitude and Z or phase difference of at least one of the high voltages of opposite phase, the voltage detection unit and the correction unit The feedback control unit can be easily configured with these two circuits.
  • the voltage detection unit is configured to include a rectification unit that rectifies the detection voltage
  • the detection voltage can be easily processed by the correction unit.
  • the correction unit includes a determination unit that compares and calculates the detection voltage and an arbitrary reference voltage
  • the correction unit can be simply configured using a general-purpose amplifier such as an operational amplifier. be able to. If such a lighting device for a display device is incorporated into a display device, the life as a light source used in the display device is prevented from being shortened.
  • FIG. 1 is an exploded perspective view showing a schematic configuration of a display device according to an embodiment of the present invention.
  • FIG. 2 is a diagram showing a schematic configuration of a power supply device that applies a high voltage to the paired discharge tubes shown in FIG.
  • FIG. 3 is a diagram showing a modification of the feedback control unit shown in FIG.
  • FIG. 4 is a diagram showing an outline of a lighting method according to the prior art in which high voltages having opposite phases are alternately applied to both end electrodes of two series discharge tubes.
  • FIG. 1 is an exploded perspective view schematically showing a main part of the structure of a display device according to an embodiment of the present invention.
  • FIG. 2 is a diagram showing a circuit configuration for driving by applying high voltages of opposite phases to both end electrodes of the two series discharge tubes 7 and 8 shown in FIG.
  • a liquid crystal display device 1 shown in FIG. 1 includes a bezel 2, a display panel 3, and a display device illumination device 4.
  • the bezel 2 is a frame member of the display panel 3, and the display panel 3 is formed by bonding two pieces of glass and sealing a liquid crystal therebetween.
  • the display device illumination device 4 includes a frame 5, optical sheets 6, a pair of discharge tubes 7, 8, a reflecting plate 10, a knocklight chassis 11, a side holder 12, and an inverter circuit board 13. Is done.
  • the frame 5 has a frame shape, and is for fixing the optical sheets 6 to the mounting surface of the backlight chassis 11 and the side holder 12.
  • the optical sheets 6 are for adjusting the characteristics of light incident on the display panel 3 from the discharge tubes 7 and 8, and are composed of, for example, a diffusion sheet, a lens sheet, a polarization reflection sheet, a diffusion plate, and the like.
  • the discharge tubes 7 and 8 are fixed to the knock light chassis 11 by attaching electrode holders 15 and 16 to end portions of the high voltage sides 7a and 8a that are driven at a high voltage.
  • the reflector 10 installed under the discharge tubes 7 and 8 is for reflecting the light emitted from the discharge tubes 7 and 8 to the display panel 3 side.
  • the backlight chassis 11 and the side holder 12 are members for forming a discharge tube housing portion that houses a plurality of discharge tubes 7 and 8 that are paired in parallel.
  • the backlight chassis 11 is formed in a substantially box shape by sheet metal processing of a metal plate material, and constitutes the bottom portion of the discharge tube housing portion and the side wall portion on the long side.
  • the side holder 12 is a white resin member and similarly forms a side wall portion on the short side of the discharge tube housing portion.
  • an inverter circuit board 13 that generates a high-voltage pulse voltage that drives the discharge tubes 7 and 8 and an inverter circuit board cover 13 a that covers the inverter circuit board 13 are provided on the rear surface of the knocklight chassis 11. ing.
  • the electrodes on the low-pressure sides 7b and 8b opposite to the high-pressure sides 7a and 8a of the discharge tubes 7 and 8 are connected in common to form a connecting portion 9.
  • a feedback electric wire 20 is connected to the connecting portion 9, and in this case, it passes between the discharge tubes 7 and 8 and is connected to the high-voltage side 7 a and 8 a.
  • the poles are connected and connected to the connector 17 to be connected centrally! RU
  • the illustrated power supply device 21 includes a power supply unit 22 that applies a high voltage in reverse phase to the high voltage sides 7a and 8a of the discharge tubes 7 and 8, and a connection unit 9 in which the low voltage sides 7b and 8b are connected.
  • the feedback control unit 23 adjusts the voltages Va and Vb applied from the power supply unit 22 to the high voltage side 7a and 8a according to the generated detection voltage Vc.
  • the power supply unit 22 is for applying a high voltage of opposite phase alternately to the two end electrodes of the two series discharge tubes 7, 8, and is a DC power source (for example, 12V) input from an external power source. ) To convert to AC pulse voltage, oscillation control unit 22a to control the switching operation of the power drive unit 22b, and AC pulse voltage output from the power drive unit 22b.
  • the power converter 22c is configured to be boosted to a high voltage of several hundred volts (V) or more and supplied to the discharge tubes 7 and 8.
  • the feedback control unit 23 applies a voltage detection unit 23a that detects the detection voltage Vc from the feedback electric wire 20 to the discharge tubes 7 and 8 from the power supply unit 22 according to the detection voltage Vc. And a correction unit 23b that supplies a signal for adjusting the amplitude and Z or phase difference of at least one of the high-phase voltages Va and Vb of opposite phase to the power supply unit 22.
  • the voltage detection unit 23a is provided with a rectification unit 23c for rectifying the detection voltage Vc.
  • the rectifier 23c is a half-wave rectifier circuit composed of diodes Dl, D2, resistor R1, and capacitor C1.
  • the correction unit 23b is provided with a determination unit 23d that compares and calculates the voltage Vd that is an output from the voltage detection unit 23a and an arbitrary reference voltage.
  • the determination unit 23d includes resistors R3, R4, R5, R6, capacitors C2, C3, a reference voltage Vref from a constant voltage generating power source, and an error amplifier OP.
  • the output voltage Vd from the rectifier 23c of the voltage detector 23a is fed back to the inverting input side of the error amplifier OP.
  • a voltage obtained by further dividing the reference voltage Vref and Vd divided by the resistors R5 and R6 by the resistors R3 and R4 is input to the non-inverting input side of the error amplifier OP.
  • the input voltages are compared, and the difference signal S is input to the oscillation control unit 22a of the power supply unit 22.
  • the oscillation control unit 22a performs feedback control so that the amplitude of the detection voltage Vc of the coupling unit 9 is reduced by controlling the switching operation in the direction in which the difference signal S decreases.
  • the difference between the positive and negative amplitudes of the tube voltages applied to the discharge tubes 7 and 8 is suppressed, and the discharge tube is prevented from reaching a short life.
  • FIG. 3 shows the configuration of the feedback control unit 24 when there are a plurality of discharge tubes 7 and 8 paired in this way.
  • the rectifier of the voltage detector is not limited to a half-wave rectifier circuit that can be a full-wave rectifier circuit.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Circuit Arrangements For Discharge Lamps (AREA)

Abstract

A display device-use lighting system capable of preventing the shorter-life of a discharge tube when the discharge tube is lighted by alternately applying inverse-phase high voltages to the opposite-end electrodes of two discharge tubes connected in series. The lighting system comprises a power supply unit (22) for applying inverse-phase high voltages Va, Vb to the high-voltage sides (7a, 8a) of respective two discharge tubes (7, 8) connected at their low-voltage sides (7b, 8b), and a feedback control unit (23) for regulating voltages Va, Vb applied to the high-voltage sides (7a, 8a) of the discharge tubes (7, 8) from the power supply unit (22) according to a voltage Vc produced at a connection portion (9) where the low-voltage sides (7b, 8b) of the two discharge tubes (7, 8) are connected.

Description

明 細 書  Specification
表示装置用照明装置及び表示装置  LIGHTING DEVICE FOR DISPLAY DEVICE AND DISPLAY DEVICE
技術分野  Technical field
[0001] 本発明は、液晶表示装置などの表示装置に好適に用いられる表示装置用照明装 置に関するものである。  TECHNICAL FIELD [0001] The present invention relates to a display device illumination device suitably used for a display device such as a liquid crystal display device.
背景技術  Background art
[0002] 表示装置の例として、たとえば液晶表示パネルを備える液晶表示装置などは、一 般的に液晶表示パネルの背面側に照明装置が配置される。この照明装置には、通 常、光源として冷陰極放電管が備えられており、この放電管から発せられる光の特性 が調整されて表示パネルの背面側に照射される。照射された光は、表示パネルを透 過することにより、この表示パネルの前面側に画像が表示される。  As an example of a display device, for example, a liquid crystal display device including a liquid crystal display panel generally has an illumination device arranged on the back side of the liquid crystal display panel. This illuminating device is usually provided with a cold cathode discharge tube as a light source, and the characteristics of light emitted from the discharge tube are adjusted to irradiate the back side of the display panel. The irradiated light passes through the display panel, and an image is displayed on the front side of the display panel.
[0003] 近年、大型液晶表示装置用などの液晶表示パネルの大型化に伴 、、長尺の放電 管が用いられているが、放電管の低圧側をリターン線で戻す一般的な接続形態では 、リターン線用の基板を必要とすることから、この基板が照明装置の小型化の障害と なっていた。また、リターン線を放電管の高圧側に設けられる電源供給部を有するィ ンバータ回路基板にまで延設する作業も煩雑であった。  [0003] In recent years, along with the increase in the size of liquid crystal display panels for large liquid crystal display devices and the like, long discharge tubes have been used, but in a general connection configuration in which the low pressure side of the discharge tube is returned by a return line. Since a substrate for the return line is required, this substrate has become an obstacle to miniaturization of the lighting device. Also, the work of extending the return line to the inverter circuit board having the power supply unit provided on the high voltage side of the discharge tube is complicated.
[0004] そこで、図 4に示すようなで 2本の放電管 7, 8を低圧側 7b, 8bで連結し、それぞれ の放電管 7, 8の高圧側 7a, 8aに電源供給部 22から交互に逆位相の高電圧 Va, Vb を印加する方法が提案されて 、る（特開 2002— 278471号公報参照)。これによつ て、放電管のリターン線が不要となるため、上記の問題を解決できる。  Therefore, as shown in FIG. 4, two discharge tubes 7 and 8 are connected at the low pressure sides 7b and 8b, and the high voltage sides 7a and 8a of the respective discharge tubes 7 and 8 are alternately connected from the power supply unit 22. A method of applying high voltages Va and Vb having opposite phases to each other has been proposed (see Japanese Patent Application Laid-Open No. 2002-278471). This eliminates the need for the return line of the discharge tube, thus solving the above problem.
発明の開示  Disclosure of the invention
発明が解決しょうとする課題  Problems to be solved by the invention
[0005] し力しながら、このような 2本直列の放電管の両端電極に交互に逆位相の高電圧を 印加することで放電管を点灯する方法においては、以下のような問題があった。一般 的に冷陰極放電管には、水銀と希ガスが封入されており、正弦波電圧によって放電 が開始されると、水銀イオンが発生し電極間に作用する電界によって加速され陰極 に移動する性質を持って 、る。通常は正負の振幅が等 、正弦波で点灯すれば水 銀イオンの移動は正負の 1周期では見かけ上は移動しない。 [0005] However, in the method of lighting the discharge tube by alternately applying a high voltage in the opposite phase to both end electrodes of the two series discharge tubes, there are the following problems. . Generally, a cold cathode discharge tube contains mercury and a rare gas. When discharge is started by a sinusoidal voltage, mercury ions are generated and accelerated by the electric field acting between the electrodes, and move to the cathode. Have Normally, positive and negative amplitudes are equal, and if sine wave lights up, water The movement of silver ions does not seem to move in one positive and negative cycle.
[0006] ところ力 図 4に示すような放電管 7, 8に逆位相の高電圧 Va, Vbを印加すると、連 結部 9に電位差 Vcが生じて、それぞれの放電管 7, 8に印加される管電圧の正負の 振幅が異なってしまう現象が発生して 、た。このように管電圧の正負の振幅が異なる と水銀に偏りが生じ、水銀が一定以下になると電極付近でピンク放電 (希ガス発光)し 、最悪短寿命に至るおそれがある。  However, when high voltages Va and Vb having opposite phases are applied to the discharge tubes 7 and 8 as shown in FIG. 4, a potential difference Vc is generated at the connecting portion 9 and applied to the discharge tubes 7 and 8, respectively. There was a phenomenon that the positive and negative amplitudes of the tube voltage differed. Thus, when the positive and negative amplitudes of the tube voltage are different, the mercury is biased, and when the mercury falls below a certain level, pink discharge (rare gas emission) may occur near the electrodes, leading to the worst life.
[0007] そこで、本発明が解決しょうとする課題は、 2本直列の放電管の両端電極に交互に 逆位相の高電圧を印加することで放電管を点灯する場合にぉ 、て、放電管の短寿 命化が防止される表示装置用照明装置及びこれを備えた表示装置を提供することで ある。  [0007] Therefore, the problem to be solved by the present invention is that when a discharge tube is turned on by alternately applying a high voltage of opposite phase to both end electrodes of a series of two discharge tubes, the discharge tube It is an object to provide a display device illumination device and a display device including the same.
課題を解決するための手段  Means for solving the problem
[0008] 上記課題を解決するため、本発明に係る表示装置用照明装置は、表示パネルの 背面側に複数本の放電管が配された表示装置用照明装置であって、 N (Nは 2以上 の整数)本の前記放電管の低圧側が連結されたそれぞれの放電管の高圧側に逆位 相の高電圧を印加する電源供給部と、前記 N本の放電管の低圧側が連結された連 結部に発生する電圧に応じて前記電源供給部力 前記放電管の高圧側に印加され る電圧を調整するフィードバック制御部とが備えられていることを要旨とするものであ る。 [0008] In order to solve the above problems, a display device illumination device according to the present invention is a display device illumination device in which a plurality of discharge tubes are arranged on the back side of a display panel, and N (N is 2 (Integer above) A power supply unit for applying a high voltage in the opposite phase to the high voltage side of each discharge tube to which the low voltage side of the discharge tube is connected, and a connection to which the low voltage side of the N discharge tubes is connected The gist of the invention is that the power supply section force is provided with a feedback control section that adjusts the voltage applied to the high voltage side of the discharge tube according to the voltage generated at the connection section.
[0009] この場合、前記フィードバック制御部には、前記低圧側の連結部に発生する電圧を 検出する電圧検出部と、この検出電圧に応じて前記電源供給部から前記放電管の それぞれに印加される逆位相の高電圧の少なくとも一方の振幅及び Z又は位相差 を調整するための信号を前記電源供給部に供給する補正部とが設けられている構 成であると良い。  [0009] In this case, the feedback control unit is applied to each of the discharge tubes from the voltage detection unit that detects a voltage generated in the low-voltage side coupling unit, and from the power supply unit according to the detected voltage. And a correction unit that supplies a signal for adjusting the amplitude and Z or phase difference of at least one of the high voltages of opposite phases to the power supply unit.
[0010] また、前記電圧検出部には、前記検出電圧を整流する整流部が設けられている構 成であると良い。更に、前記補正部には、前記検出電圧と任意の基準電圧とを比較 演算する判定部が設けられている構成であると良い。そして、このような表示装置用 照明装置を備えてなる表示装置である構成にすると良い。  [0010] The voltage detection unit may be configured to include a rectification unit that rectifies the detection voltage. Furthermore, it is preferable that the correction unit is provided with a determination unit that compares and calculates the detected voltage and an arbitrary reference voltage. And it is good to set it as the structure which is a display apparatus provided with such an illuminating device for display apparatuses.
発明の効果 [0011] 上記構成を有する表示装置用照明装置によれば、少なくとも 2本の放電管の低圧 側が連結されたそれぞれの放電管の高圧側に逆位相の高電圧を印加する電源供給 部と、放電管の低圧側が連結された連結部に発生する電圧に応じて電源供給部か ら放電管の高圧側に印加される電圧を調整するフィードバック制御部とが備えられて いるので、連結部に発生する電圧を小さくすることが可能である。これにより、管電圧 の正負の振幅が異なってしまうことが抑制され、放電管が短寿命に至ることが防止さ れる。 The invention's effect [0011] According to the illumination device for a display device having the above-described configuration, a power supply unit that applies a high voltage in the opposite phase to the high voltage side of each discharge tube in which the low voltage sides of at least two discharge tubes are connected, and the discharge A feedback control unit that adjusts the voltage applied from the power supply unit to the high voltage side of the discharge tube according to the voltage generated at the coupling unit connected to the low voltage side of the tube is provided. It is possible to reduce the voltage. This suppresses the difference between the positive and negative amplitudes of the tube voltage and prevents the discharge tube from reaching a short life.
[0012] この場合、前記フィードバック制御部には、前記低圧側の連結部に発生する電圧を 検出する電圧検出部と、この検出電圧に応じて前記電源供給部から前記放電管の それぞれに印加される逆位相の高電圧の少なくとも一方の振幅及び Z又は位相差 を調整するための信号を前記電源供給部に供給する補正部とが設けられている構 成にすれば、電圧検出部と補正部という 2つの回路でフィードバック制御部を簡易に 構成することができる。  [0012] In this case, the feedback control unit is applied to each of the discharge tubes from the voltage detection unit that detects a voltage generated in the low-voltage side coupling unit and the power supply unit according to the detected voltage. If the configuration includes a correction unit that supplies the power supply unit with a signal for adjusting the amplitude and Z or phase difference of at least one of the high voltages of opposite phase, the voltage detection unit and the correction unit The feedback control unit can be easily configured with these two circuits.
[0013] また、前記電圧検出部には、前記検出電圧を整流する整流部が設けられている構 成にすれば、補正部による検出電圧の処理が容易になる。更に、前記補正部には、 前記検出電圧と任意の基準電圧とを比較演算する判定部が設けられている構成に すれば、補正部をオペアンプなどの汎用の増幅器を用いて簡易に回路構成すること ができる。そして、このような表示装置用照明装置を組み込んで表示装置とすれば、 表示装置に用いられる光源としての寿命が短くなつてしまうことが防止される。  [0013] Further, if the voltage detection unit is configured to include a rectification unit that rectifies the detection voltage, the detection voltage can be easily processed by the correction unit. Furthermore, if the correction unit includes a determination unit that compares and calculates the detection voltage and an arbitrary reference voltage, the correction unit can be simply configured using a general-purpose amplifier such as an operational amplifier. be able to. If such a lighting device for a display device is incorporated into a display device, the life as a light source used in the display device is prevented from being shortened.
図面の簡単な説明  Brief Description of Drawings
[0014] [図 1]本発明の一実施形態に係る表示装置の概略構成を示す分解斜視図である。  FIG. 1 is an exploded perspective view showing a schematic configuration of a display device according to an embodiment of the present invention.
[図 2]図 1に示される対になった放電管に高電圧を印加する電源装置の概略構成を 示した図である。  2 is a diagram showing a schematic configuration of a power supply device that applies a high voltage to the paired discharge tubes shown in FIG.
[図 3]図 2に示したフィードバック制御部の変形例を示した図である。  3 is a diagram showing a modification of the feedback control unit shown in FIG.
[図 4]従来技術に係る 2本直列の放電管の両端電極に交互に逆位相の高電圧を印 加する点灯方法の概略を示した図である。  FIG. 4 is a diagram showing an outline of a lighting method according to the prior art in which high voltages having opposite phases are alternately applied to both end electrodes of two series discharge tubes.
発明を実施するための最良の形態  BEST MODE FOR CARRYING OUT THE INVENTION
[0015] 以下に、本発明の係る表示装置の実施の形態ついて、図面を参照して詳細に説明 する。図 1は、本発明の一実施形態に係る表示装置の構造の要部を模式的に示した 分解斜視図である。図 2は、図 1に示される 2本直列の放電管 7, 8の両端電極に交 互に逆位相の高電圧を印力!]して駆動する回路構成を示した図である。 Hereinafter, embodiments of a display device according to the present invention will be described in detail with reference to the drawings. To do. FIG. 1 is an exploded perspective view schematically showing a main part of the structure of a display device according to an embodiment of the present invention. FIG. 2 is a diagram showing a circuit configuration for driving by applying high voltages of opposite phases to both end electrodes of the two series discharge tubes 7 and 8 shown in FIG.
[0016] 図 1に示される液晶表示装置 1は、べゼル 2、表示パネル 3、及び表示装置用照明 装置 4を備える。べゼル 2は表示パネル 3の額縁となる部材で、表示パネル 3は、 2枚 のガラスを貼り合わせてその間に液晶を封止したものである。  A liquid crystal display device 1 shown in FIG. 1 includes a bezel 2, a display panel 3, and a display device illumination device 4. The bezel 2 is a frame member of the display panel 3, and the display panel 3 is formed by bonding two pieces of glass and sealing a liquid crystal therebetween.
[0017] 表示装置用照明装置 4は、フレーム 5、光学シート類 6、対になった放電管 7, 8、反 射板 10、ノ ックライトシャーシ 11、サイドホルダー 12及びインバーター回路基板 13 力も構成される。フレーム 5は、額縁形状を有しており、光学シート類 6をバックライト シャーシ 11及びサイドホルダー 12の載置面に固定するためのものである。光学シー ト類 6は、放電管 7, 8から表示パネル 3に入射する光の特性を調整するためのもので 、例えば、拡散シート、レンズシート、偏光反射シート、拡散板等から構成される。  [0017] The display device illumination device 4 includes a frame 5, optical sheets 6, a pair of discharge tubes 7, 8, a reflecting plate 10, a knocklight chassis 11, a side holder 12, and an inverter circuit board 13. Is done. The frame 5 has a frame shape, and is for fixing the optical sheets 6 to the mounting surface of the backlight chassis 11 and the side holder 12. The optical sheets 6 are for adjusting the characteristics of light incident on the display panel 3 from the discharge tubes 7 and 8, and are composed of, for example, a diffusion sheet, a lens sheet, a polarization reflection sheet, a diffusion plate, and the like.
[0018] 放電管 7, 8は、高圧駆動される高圧側 7a, 8aの端部に電極部ホルダ 15, 16が装 着されて、ノ ックライトシャーシ 11に固定される。この放電管 7, 8の下側に布設される 反射板 10は、放電管 7, 8から発せられる光を表示パネル 3側に反射させるためのも のである。バックライトシャーシ 11とサイドホルダー 12は対になった放電管 7, 8を複 数並列に収容する放電管収容部を形成するための部材である。この場合、バックライ トシャーシ 11は、金属製板材の板金加工により略箱形状に形成されたもので、放電 管収容部の底部と長辺側の側壁部を構成する。サイドホルダー 12は、白色の榭脂製 部材で、同じく放電管収容部の短辺側の側壁部を構成して 、る。  The discharge tubes 7 and 8 are fixed to the knock light chassis 11 by attaching electrode holders 15 and 16 to end portions of the high voltage sides 7a and 8a that are driven at a high voltage. The reflector 10 installed under the discharge tubes 7 and 8 is for reflecting the light emitted from the discharge tubes 7 and 8 to the display panel 3 side. The backlight chassis 11 and the side holder 12 are members for forming a discharge tube housing portion that houses a plurality of discharge tubes 7 and 8 that are paired in parallel. In this case, the backlight chassis 11 is formed in a substantially box shape by sheet metal processing of a metal plate material, and constitutes the bottom portion of the discharge tube housing portion and the side wall portion on the long side. The side holder 12 is a white resin member and similarly forms a side wall portion on the short side of the discharge tube housing portion.
[0019] また、ノ ックライトシャーシ 11の裏面には、放電管 7, 8を駆動する高圧パルス電圧 を発生させるインバータ回路基板 13と、このインバータ回路基板 13を覆うインバータ 回路基板カバー 13aが設けられている。尚、表示パネル 3を制御するコントロール回 路基板 14と、このコントロール回路基板 14を覆うコントロール回路基板カバー 14aも バックライトシャーシ 11の裏面に設けられて 、る。  In addition, an inverter circuit board 13 that generates a high-voltage pulse voltage that drives the discharge tubes 7 and 8 and an inverter circuit board cover 13 a that covers the inverter circuit board 13 are provided on the rear surface of the knocklight chassis 11. ing. A control circuit board 14 that controls the display panel 3 and a control circuit board cover 14a that covers the control circuit board 14 are also provided on the back surface of the backlight chassis 11.
[0020] 図示されるように、放電管 7, 8の高圧側 7a, 8aとは反対側の低圧側 7b, 8bの電極 は共通接続されて連結部 9が形成されている。また、この連結部 9にはフィードバック 電線 20が接続されており、この場合、放電管 7, 8の間を通って、高圧側 7a, 8aの電 極が接続されて 、るコネクタ 17にまで延設されて集中接続されて！、る。 As shown in the figure, the electrodes on the low-pressure sides 7b and 8b opposite to the high-pressure sides 7a and 8a of the discharge tubes 7 and 8 are connected in common to form a connecting portion 9. In addition, a feedback electric wire 20 is connected to the connecting portion 9, and in this case, it passes between the discharge tubes 7 and 8 and is connected to the high-voltage side 7 a and 8 a. The poles are connected and connected to the connector 17 to be connected centrally! RU
[0021] 次に、このような構成の 2本直列の放電管 7, 8の両端電極に、交互に逆位相の高 電圧を印力 tlして駆動する図 2の電源装置 21について説明する。  Next, a description will be given of the power supply device 21 in FIG. 2 that is driven by alternately applying a high voltage having an opposite phase to both end electrodes of the two series discharge tubes 7 and 8 having such a configuration.
[0022] 図示される電源装置 21は、放電管 7, 8の高圧側 7a, 8aに逆位相の高電圧を印加 する電源供給部 22と、低圧側 7b, 8bが連結された連結部 9に発生する検出電圧 Vc に応じて電源供給部 22から高圧側 7a, 8aに印加される電圧 Va, Vbを調整するフィ ードバック制御部 23とから構成されて 、る。  The illustrated power supply device 21 includes a power supply unit 22 that applies a high voltage in reverse phase to the high voltage sides 7a and 8a of the discharge tubes 7 and 8, and a connection unit 9 in which the low voltage sides 7b and 8b are connected. The feedback control unit 23 adjusts the voltages Va and Vb applied from the power supply unit 22 to the high voltage side 7a and 8a according to the generated detection voltage Vc.
[0023] 電源供給部 22は、 2本直列の放電管 7, 8の両端電極に交互に逆位相の高電圧を 印加するためのもので、外部カゝら入力される直流電源 (例えば、 12V)をスイッチング して交流のパルス電圧に変換する電力駆動部 22bと、この電力駆動部 22bのスイツ チング動作を制御する発振制御部 22aと、電力駆動部 22bから出力された交流のパ ルス電圧を数百ボルト (V)以上の高電圧に昇圧し、それを放電管 7, 8に供給する電 源変換部 22cとから構成されて ヽる。  [0023] The power supply unit 22 is for applying a high voltage of opposite phase alternately to the two end electrodes of the two series discharge tubes 7, 8, and is a DC power source (for example, 12V) input from an external power source. ) To convert to AC pulse voltage, oscillation control unit 22a to control the switching operation of the power drive unit 22b, and AC pulse voltage output from the power drive unit 22b. The power converter 22c is configured to be boosted to a high voltage of several hundred volts (V) or more and supplied to the discharge tubes 7 and 8.
[0024] フィードバック制御部 23は、フィードバック電線 20からの検出電圧 Vcを検出する電 圧検出部 23aと、この検出電圧 Vcに応じて電源供給部 22から放電管 7, 8のそれぞ れに印加される逆位相の高電圧 Va, Vbの少なくとも一方の振幅及び Z又は位相差 を調整するための信号を電源供給部 22に供給する補正部 23bとから構成されている  [0024] The feedback control unit 23 applies a voltage detection unit 23a that detects the detection voltage Vc from the feedback electric wire 20 to the discharge tubes 7 and 8 from the power supply unit 22 according to the detection voltage Vc. And a correction unit 23b that supplies a signal for adjusting the amplitude and Z or phase difference of at least one of the high-phase voltages Va and Vb of opposite phase to the power supply unit 22.
[0025] 電圧検出部 23aには、検出電圧 Vcを整流する整流部 23cが設けられて ヽる。整流 部 23cはこの場合、ダイオード Dl, D2,抵抗 R1,コンデンサ C1から構成される半波 整流回路となっている。また、補正部 23bには、電圧検出部 23aからの出力である電 圧 Vdと任意の基準電圧とを比較演算する判定部 23dが設けられて ヽる。この判定部 23dはこの場合、抵抗 R3, R4, R5, R6、コンデンサ C2, C3と、定電圧発生電源か らの参照電圧 Vref ,誤差増幅器 OPから構成されて 、る。 [0025] The voltage detection unit 23a is provided with a rectification unit 23c for rectifying the detection voltage Vc. In this case, the rectifier 23c is a half-wave rectifier circuit composed of diodes Dl, D2, resistor R1, and capacitor C1. Further, the correction unit 23b is provided with a determination unit 23d that compares and calculates the voltage Vd that is an output from the voltage detection unit 23a and an arbitrary reference voltage. In this case, the determination unit 23d includes resistors R3, R4, R5, R6, capacitors C2, C3, a reference voltage Vref from a constant voltage generating power source, and an error amplifier OP.
[0026] この場合、電圧検出部 23aの整流部 23cからの出力電圧 Vdは、誤差増幅器 OPの 反転入力側にフィードバック入力されている。また、参照電圧 Vref及び抵抗 R5, R6 により抵抗分圧された Vdが更に抵抗 R3, R4により抵抗分圧された電圧が、誤差増 幅器 OPの非反転入力側に入力されている。そして、誤差増幅器 OPにおいてこれら 入力された電圧は比較され、その差信号 Sが電源供給部 22の発振制御部 22aに入 力される。発振制御部 22aは差信号 Sが減少する方向にスイッチング動作の制御を 行うことにより、連結部 9の検出電圧 Vcの振幅が小さくなるようにフィードバック制御さ れる。これにより、放電管 7, 8に印加される管電圧の正負の振幅が異なることが抑制 され、放電管が短寿命に至ることが防止される。 In this case, the output voltage Vd from the rectifier 23c of the voltage detector 23a is fed back to the inverting input side of the error amplifier OP. A voltage obtained by further dividing the reference voltage Vref and Vd divided by the resistors R5 and R6 by the resistors R3 and R4 is input to the non-inverting input side of the error amplifier OP. And these in the error amplifier OP The input voltages are compared, and the difference signal S is input to the oscillation control unit 22a of the power supply unit 22. The oscillation control unit 22a performs feedback control so that the amplitude of the detection voltage Vc of the coupling unit 9 is reduced by controlling the switching operation in the direction in which the difference signal S decreases. As a result, the difference between the positive and negative amplitudes of the tube voltages applied to the discharge tubes 7 and 8 is suppressed, and the discharge tube is prevented from reaching a short life.
[0027] 図 3は、このように対になった放電管 7, 8が複数ある場合のフィードバック制御部 2 4の構成を示している。図示されるように、この場合 3本のフィードバック電線 20のそ れぞれに電圧検出部 23aが接続され、これら電圧検出部 23aが並列接続されて 1つ の補正部 23bに接続されている構成なので、 3つの電圧検出部 23aからの出力電圧 Vdの最小値が誤差増幅器 OPの反転入力側に入力されてフィードバック制御が行わ れる。このようにフィードバック電線 20が複数ある場合でも、このような簡易な構成で 一度にフィードバック制御を行うことが可能である。  FIG. 3 shows the configuration of the feedback control unit 24 when there are a plurality of discharge tubes 7 and 8 paired in this way. As shown in the figure, in this case, a configuration in which a voltage detection unit 23a is connected to each of the three feedback wires 20 and these voltage detection units 23a are connected in parallel and connected to one correction unit 23b. Therefore, the minimum value of the output voltage Vd from the three voltage detectors 23a is input to the inverting input side of the error amplifier OP, and feedback control is performed. Thus, even when there are a plurality of feedback wires 20, it is possible to perform feedback control at a time with such a simple configuration.
[0028] 以上、本発明の一実施形態について説明したが、本発明はこうした実施形態に何 ら限定されるものではなぐ本発明の要旨を逸脱しない範囲において、種々なる態様 で実施できることは勿論である。例えば、電圧検出部の整流部は全波整流回路でも 良ぐ半波整流回路には限定されない。  [0028] Although one embodiment of the present invention has been described above, the present invention is not limited to such embodiment, and can of course be implemented in various modes without departing from the spirit of the present invention. is there. For example, the rectifier of the voltage detector is not limited to a half-wave rectifier circuit that can be a full-wave rectifier circuit.

Claims

請求の範囲 The scope of the claims
[1] 表示パネルの背面側に複数本の放電管が配された表示装置用照明装置であって 、 N (Nは 2以上の整数)本の前記放電管の低圧側が連結されたそれぞれの放電管 の高圧側に逆位相の高電圧を印加する電源供給部と、前記 N本の放電管の低圧側 が連結された連結部に発生する電圧に応じて前記電源供給部力 前記放電管の高 圧側に印加される電圧を調整するフィードバック制御部とが備えられていることを特 徴とする表示装置用照明装置。  [1] A lighting device for a display device in which a plurality of discharge tubes are arranged on the back side of a display panel, each of which discharges N (N is an integer of 2 or more) connected to the low pressure side of the discharge tubes A power supply unit for applying a high voltage in the opposite phase to the high voltage side of the tube, and a power supply unit force according to a voltage generated at a connection unit connected to the low voltage side of the N discharge tubes. And a feedback control unit that adjusts a voltage applied to the compression side.
[2] 前記フィードバック制御部には、前記低圧側の連結部に発生する電圧を検出する 電圧検出部と、この検出電圧に応じて前記電源供給部から前記放電管のそれぞれ に印加される逆位相の高電圧の少なくとも一方の振幅及び Z又は位相差を調整する ための信号を前記電源供給部に供給する補正部とが設けられていることを特徴とす る請求項 1に記載の表示装置用照明装置。  [2] The feedback control unit includes a voltage detection unit that detects a voltage generated at the low-voltage side coupling unit, and an antiphase applied to each of the discharge tubes from the power supply unit according to the detected voltage. 2. The display device according to claim 1, further comprising: a correction unit that supplies a signal for adjusting the amplitude and Z or phase difference of at least one of the high voltages to the power supply unit. Lighting device.
[3] 前記電圧検出部には、前記検出電圧を整流する整流部が設けられていることを特 徴とする請求項 2に記載の表示装置用照明装置。  3. The display device illumination device according to claim 2, wherein the voltage detection unit includes a rectification unit that rectifies the detection voltage.
[4] 前記補正部には、前記検出電圧と任意の基準電圧とを比較演算する判定部が設 けられていることを特徴とする請求項 2又は 3に記載の表示装置用照明装置。  [4] The display device illumination device according to [2] or [3], wherein the correction unit is provided with a determination unit that compares and calculates the detected voltage and an arbitrary reference voltage.
[5] 請求項 1から 4のいずれかに記載の表示装置用照明装置を備えてなることを特徴と する表示装置。  [5] A display device comprising the illumination device for a display device according to any one of claims 1 to 4.
PCT/JP2006/315185 2005-08-05 2006-08-01 Display device-use lighting system and display device WO2007018071A1 (en)

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