WO2007018071A1 - Système d’éclairage pour dispositif d’affichage et dispositif d’affichage - Google Patents

Système d’éclairage pour dispositif d’affichage et dispositif d’affichage 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
Authority
WO
WIPO (PCT)
Prior art keywords
voltage
display device
unit
discharge tubes
power supply
Prior art date
Application number
PCT/JP2006/315185
Other languages
English (en)
Japanese (ja)
Inventor
Masayuki Murao
Original Assignee
Sharp Kabushiki Kaisha
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 Sharp Kabushiki Kaisha filed Critical Sharp Kabushiki Kaisha
Publication of WO2007018071A1 publication Critical patent/WO2007018071A1/fr

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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

L’invention concerne un système d’éclairage pour dispositif d’affichage capable d’empêcher le raccourcissement de la durée de vie d’un tube de décharge lorsque le tube de décharge est éclairé par l’application alternée de hautes tensions à phase inverse aux électrodes d’extrémité opposée de deux tubes de décharge connectés en série. Le système d’éclairage comprend une unité d’alimentation (22) permettant d’appliquer des hautes tension à phase inverse Va, Vb aux côtés haute tension (7a, 8a) de deux tubes de décharge respectifs (7, 8) connectés en leurs côtés basse tension (7b, 8b), et une unité de commande de retour (23) permettant de réguler les tensions Va, Vb appliquées aux côtés haute tension (7a, 8a) des tubes de décharge (7, 8) à partir de l’unité d’alimentation (22) selon une tension voltage Vc produite en une portion de connexion (9) lorsque les côtés basse tension (7b, 8b) des deux tubes de décharge (7, 8) sont connectés.
PCT/JP2006/315185 2005-08-05 2006-08-01 Système d’éclairage pour dispositif d’affichage et dispositif d’affichage WO2007018071A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2005227748 2005-08-05
JP2005-227748 2005-08-05

Publications (1)

Publication Number Publication Date
WO2007018071A1 true WO2007018071A1 (fr) 2007-02-15

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008293840A (ja) * 2007-05-25 2008-12-04 Hitachi Displays Ltd 表示装置

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH10340788A (ja) * 1997-06-06 1998-12-22 Hitachi Ltd 放電灯点灯装置
JP2001085759A (ja) * 1999-09-13 2001-03-30 Hitachi Metals Ltd 圧電トランスの駆動方法と駆動回路
JP2002278471A (ja) * 2001-03-21 2002-09-27 Tama Electric Co Ltd バックライト装置及びバックライト装置の点灯方法
JP2003230272A (ja) * 2001-11-29 2003-08-15 Matsushita Electric Ind Co Ltd 圧電トランスの駆動回路、冷陰極管発光装置、液晶パネルおよび液晶パネル組込み機器
JP2004054294A (ja) * 2002-07-22 2004-02-19 Samsung Electronics Co Ltd 液晶表示装置及びそのバックライト駆動装置
JP2005507145A (ja) * 2001-10-23 2005-03-10 オーツー マイクロ， インコーポレーテッド 負荷駆動システム

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH10340788A (ja) * 1997-06-06 1998-12-22 Hitachi Ltd 放電灯点灯装置
JP2001085759A (ja) * 1999-09-13 2001-03-30 Hitachi Metals Ltd 圧電トランスの駆動方法と駆動回路
JP2002278471A (ja) * 2001-03-21 2002-09-27 Tama Electric Co Ltd バックライト装置及びバックライト装置の点灯方法
JP2005507145A (ja) * 2001-10-23 2005-03-10 オーツー マイクロ， インコーポレーテッド 負荷駆動システム
JP2003230272A (ja) * 2001-11-29 2003-08-15 Matsushita Electric Ind Co Ltd 圧電トランスの駆動回路、冷陰極管発光装置、液晶パネルおよび液晶パネル組込み機器
JP2004054294A (ja) * 2002-07-22 2004-02-19 Samsung Electronics Co Ltd 液晶表示装置及びそのバックライト駆動装置

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008293840A (ja) * 2007-05-25 2008-12-04 Hitachi Displays Ltd 表示装置

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