WO2013155736A1 - 背光模块的驱动电路及其应用的显示装置 - Google Patents

背光模块的驱动电路及其应用的显示装置 Download PDF

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Publication number
WO2013155736A1
WO2013155736A1 PCT/CN2012/074972 CN2012074972W WO2013155736A1 WO 2013155736 A1 WO2013155736 A1 WO 2013155736A1 CN 2012074972 W CN2012074972 W CN 2012074972W WO 2013155736 A1 WO2013155736 A1 WO 2013155736A1
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Prior art keywords
transistor
switching signal
image mode
potential
driving circuit
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PCT/CN2012/074972
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English (en)
French (fr)
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黎飞
高新明
杨翔
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深圳市华星光电技术有限公司
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Application filed by 深圳市华星光电技术有限公司 filed Critical 深圳市华星光电技术有限公司
Priority to US13/511,542 priority Critical patent/US20130271443A1/en
Priority to DE112012006232.9T priority patent/DE112012006232T5/de
Publication of WO2013155736A1 publication Critical patent/WO2013155736A1/zh

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    • 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
    • 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
    • G09G3/001—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes using specific devices not provided for in groups G09G3/02 - G09G3/36, e.g. using an intermediate record carrier such as a film slide; Projection systems; Display of non-alphanumerical information, solely or in combination with alphanumerical information, e.g. digital display on projected diapositive as background
    • G09G3/003—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes using specific devices not provided for in groups G09G3/02 - G09G3/36, e.g. using an intermediate record carrier such as a film slide; Projection systems; Display of non-alphanumerical information, solely or in combination with alphanumerical information, e.g. digital display on projected diapositive as background to produce spatial visual effects
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N13/00—Stereoscopic video systems; Multi-view video systems; Details thereof
    • H04N13/30—Image reproducers
    • H04N13/302—Image reproducers for viewing without the aid of special glasses, i.e. using autostereoscopic displays
    • H04N13/31—Image reproducers for viewing without the aid of special glasses, i.e. using autostereoscopic displays using parallax barriers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N13/00—Stereoscopic video systems; Multi-view video systems; Details thereof
    • H04N13/30—Image reproducers
    • H04N13/356—Image reproducers having separate monoscopic and stereoscopic modes
    • 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
    • G09G2330/00—Aspects of power supply; Aspects of display protection and defect management
    • G09G2330/02—Details of power systems and of start or stop of display operation

Definitions

  • the present invention relates to a driving circuit of a backlight module and a display device therefor, and more particularly to a driving circuit of a backlight module that can be applied to switch 2D/3D images and a display device thereof.
  • Liquid crystal display (Liquid Crystal Display, LCD) has been widely used in a variety of electronic products, most of the liquid crystal display is a backlight type liquid crystal display, which is composed of a liquid crystal display panel and a backlight module (backlight Module).
  • the backlight module can be divided into a side-light type and a direct-light type according to the incident position of the light source (Direct-light) Type) Two to provide a backlight to the LCD panel.
  • Direct-light Direct-light
  • LED Due to light-emitting diodes (Light-Emitting) Diode, LED) has good optoelectronic properties such as low power consumption, low heat generation, long operating life, impact resistance, small volume, fast response, and color light that emits stable wavelengths, so it is suitable for use in backlight modules.
  • displays that can switch between planar (2D) images or stereoscopic (3D) images have been developed.
  • displays that can switch 2D/3D images include 2D panels and parallax barrier panels.
  • the parallax barrier panel When the 2D image is displayed, the parallax barrier panel is in a transparent state, so that the 2D panel displays the 2D image.
  • the parallax barrier panel When displaying a 3D image, the parallax barrier panel may have a plurality of parallax barriers through which the effects of the 3D image are presented.
  • the backlight module needs to increase the brightness to compensate for the brightness loss.
  • the driving current for example, 300 mA
  • the driving current for example, 300 mA
  • a plurality of chips are required, thereby affecting the control precision and design complexity of the driving current, and increasing the driving circuit. cost.
  • the invention provides a driving circuit of a backlight module and a display device thereof applied to solve the problem of limitation of output current of the driving circuit.
  • a main object of the present invention is to provide a driving circuit for a backlight module, the driving circuit comprising: a transistor connected to the plurality of light emitting diodes; a constant current circuit connected to the transistor; a power resistor connected in parallel to the transistor; and a power switch Connected between the transistor and the power resistor, wherein a switching signal is transmitted to the power switch, and the potential of the switching signal is higher than the switching in a planar image mode in a stereoscopic image mode The potential of the signal.
  • Another object of the present invention is to provide a driving circuit for a backlight module, the driving circuit comprising: a transistor connected to the plurality of light emitting diodes; a constant current circuit connected to the transistor; a power resistor connected in parallel to the transistor; a switch connected between the transistor and the power resistor, wherein a switching signal is transmitted to the power switch, and a potential of the switching signal is higher than a plane image mode in a stereoscopic image mode The potential of the switching signal in which the potential of the switching signal is higher than 2.5 volts, and the potential of the switching signal is lower than 0.8 volts in the planar image mode.
  • the backlight module includes: a backplane; a plurality of light emitting diodes disposed on the backplane; and a driving circuit electrically connected to the light emitting diode, wherein the driving circuit comprises: a transistor connected to the light emitting diode; and a constant current circuit Connected to the transistor; a power resistor connected in parallel to the transistor; and a power switch connected between the transistor and the power resistor, wherein a switching signal is transmitted to the power switch in a stereoscopic image mode The potential of the switching signal is higher than the potential of the switching signal in a planar image mode.
  • the potential of the switching signal is higher than 2.5 volts in the stereoscopic image mode.
  • the potential of the switching signal in the stereoscopic image mode is between 2.5 volts and 3.3 volts.
  • the potential of the switching signal is less than 0.8 volts in the planar image mode.
  • the driving circuit further includes a multiplier for multiplying the switching signal and a pulse width modulation signal, and transmitting the multiplied signal to the power switch.
  • the driving circuit further includes a resistor connected to the transistor.
  • the constant current circuit includes a voltage regulator and an amplifier, the voltage regulator is connected between the power source and the amplifier, and the amplifier is connected to the first transistor.
  • the voltage regulator is a low dropout linear regulator.
  • the current obtained by the LED in the stereoscopic image mode is twice the current obtained by the LED in the planar image mode.
  • the driving circuit of the backlight module of the present invention and the display device thereof can simplify the design of the driving circuit, and can use a single driving IC chip to ensure the control precision of the driving current and save the cost of the driving circuit.
  • FIG. 1 shows a schematic cross-sectional view of a display device in accordance with an embodiment of the present invention
  • FIG. 2 shows a circuit diagram of a drive circuit in accordance with an embodiment of the present invention.
  • the driving circuit 150 of this embodiment can be used to drive a plurality of light emitting diodes of the backlight module 100 (Light-Emitting) Diode, LED) 120, these LEDs 120 can be connected in series to form a string of LEDs to serve as a light source for the backlight module 100.
  • the backlight module 100 can be a lateral light input or a direct light input light, which is disposed relative to a display panel 101 (for example, a liquid crystal display panel) to form a display device (for example, a liquid crystal display device).
  • the display device can be switched to a planar (2D) image mode or a stereoscopic (3D) image mode according to the user's needs to display 2D or 3D images respectively.
  • the display device further includes a parallax barrier panel 102 for displaying a 2D image, and the parallax barrier panel 102 can be disposed at one side (light exiting side) of the display panel 110 for forming a parallax in a 3D image mode.
  • the barrier effect and the effect of forming a 3D image through the parallax barrier panel 102 may be formed by other methods.
  • the backlight module 100 can be, for example, a direct type backlight module, including a back plate 110 , a plurality of light emitting diodes (LEDs) 120 , a circuit board 130 , a reflective layer 140 , a driving circuit 150 , and Optical film 160.
  • the backplane 110 is configured to carry the LED 120 and the circuit board 130.
  • the LED 120 can be disposed on the circuit board 130 and electrically connected to the driving circuit 150 through the circuit board 130 for emitting light to the display panel 101.
  • Circuit board 130 can be a printed circuit board (Printed Circuit board, PCB) or flexible printed circuit board (Flexible Printed Circuits, FPC).
  • the reflective layer 140 is formed around the light emitting diode 120 (for example, formed on the circuit board 130 or the back plate 110) to reflect the light of the LED 120.
  • the driving circuit 150 can be electrically connected to the light emitting diode 120 through the circuit board 130.
  • the optical film 160 is disposed above the light emitting diode 120 to improve the uniformity of illumination or the luminous efficiency of the light emitting diode 120.
  • the driving circuit of the present invention can also be applied to a laterally-lit backlight module (not shown).
  • the driving circuit 150 of this embodiment includes a first transistor T1, a second transistor T2, a constant current circuit 151, a first power switch Q1, a second power switch Q2, resistors R1, R3, power resistors R2, R4, and a multiplier 152.
  • the transistors T1 and T2 are connected to the light emitting diode 120
  • the constant current circuit 151 is connected to the transistors T1 and T2
  • the power resistors R2 and R4 are connected in parallel to the transistors T1 and T2
  • the power switches Q1 and Q2 are connected to the transistors T1 and T2, respectively.
  • the multiplier 152 is connected to the power switches Q1 and Q2.
  • One of the switching signals can be transmitted to the power switch by a multiplier 152 for switching planar (2D)/stereoscopic (3D) images.
  • this switching signal can be referred to as a 2D/3D switching signal.
  • the transistors T1 and T2 can be bipolar transistors (Bipolar Junction). Transistor, BJT) or Metal Oxygen Half Field Effect Transistor (Metal-Oxide- Semiconductor Field-Effect Transistor, MOSFET).
  • the collector of the first transistor T1 can be connected to the first LED string 121.
  • the emitter of the first transistor T1 is connected to the first node N1, and the base of the first transistor T1 is connected to the constant current circuit 151.
  • the collector of the second transistor T2 can be connected to the second LED string 122, the emitter of the second transistor T2 is connected to the second node N2, and the base of the second transistor T2 is connected to the constant current circuit 151.
  • the constant current circuit 151 can be a constant current IC chip for stabilizing the current of the light emitting diode 120, so that the light emitting diode 120 can have a uniform current.
  • the constant current circuit 151 may include a voltage regulator 153 and amplifiers V1 and V2, and the voltage regulator 153 is, for example, a low dropout linear regulator (Low). Drop-out linear Regulator), which is connected between the power supply VCC and the amplifiers V1, V2.
  • the amplifier V1 is respectively connected to the base of the first transistor T1, and the amplifier V2 is respectively connected to the base of the second transistor T2, wherein a pulse width modulation (PWM) signal is respectively transmitted to the amplifiers V1, V2.
  • PWM pulse width modulation
  • the power switches Q1 and Q2 are, for example, depletion type N-channel metal oxide semiconductor (NMOS) transistors.
  • NMOS metal oxide semiconductor
  • the drain of the first power switch Q1 is connected to the LED 120, the source of the first power switch Q1 is connected to the power resistor R2, and the gate of the first power switch Q1 is connected to the multiplier 152.
  • the drain of the second power switch Q2 is connected to the LED 120, the source of the second power switch Q2 is connected to the power resistor R4, and the gate of the second power switch Q2 is connected to the multiplier 152.
  • the resistor R3 is connected between the emitter of the second transistor T2 and the ground, and the power resistor R2 is connected between the first node N1 and the first power switch Q1, so that the power resistor R2 is connected in parallel with the first power switch Q1.
  • the power resistor R4 is connected between the second node N2 and the second power switch Q2 such that the power resistor R4 and the second power switch Q2 are connected in parallel to the second transistor T2.
  • the multiplier 152 is configured to multiply the 2D/3D switching signal and the PWM signal, and transmit the multiplied signal to the power switches Q1 and Q2 to switch the power switch.
  • the Q1 and Q2. 2D/3D switching signals may be provided by a controller (not shown) of the display device of the present invention, which may be provided by an external system terminal (not shown) and passed through, for example, a timing controller (not shown). It is transmitted to the constant current circuit 151 and the multiplier 152.
  • the 2D/3D switching signals can be transmitted to the power switches Q1 and Q2 after multiplication by the multiplier 152.
  • the 2D/3D switching signal is a low level signal, thus turning off the power switches Q1 and Q2. Therefore, the current obtained by the LED 120 is only the current flowing through the transistors T1 and T2.
  • the 2D/3D switching signals can be transmitted to the power switches Q1 and Q2 after multiplication by the multiplier 152.
  • the 2D/3D switching signal is a high level signal, thus turning on the power switches Q1 and Q2. Therefore, the current obtained by the LED 120 can be the sum of the current flowing through the transistors T1 and T2 and the power resistors R2 and R4, and the driving current of the LED 120 is greatly increased, so that the LED 120 is greatly improved in the 3D image mode. Brightness, to avoid the image brightness of the display device is inconsistent in the 2D/3D image mode.
  • the current obtained by the LED 120 in the 3D image mode may be about twice the current obtained by the LED 120 in the 2D image mode.
  • the potential of the 2D/3D switching signal in the 3D image mode is higher than the potential of the 2D/3D switching signal in the 2D image mode.
  • the potential of the 2D/3D switching signal in the 3D image mode may be higher than 2.5 volts, for example between 2.5 volts and 3.3 volts.
  • the potential of the 2D/3D switching signal in the 2D image mode may be less than 0.8 volts, such as between 0 volts and 0.8 volts.
  • the driving circuit of the backlight module of the present invention and the display device to which the same is applied can use a simple circuit in the backlight module of the switchable 2D/3D display device to improve the backlight brightness in the 3D image mode.
  • the design of the driving circuit can be simplified, and a single driving IC chip can be used to ensure the control precision of the driving current and save the cost of the driving circuit.

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  • Signal Processing (AREA)
  • Physics & Mathematics (AREA)
  • Computer Hardware Design (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
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Abstract

一种背光模块的驱动电路及其应用的显示装置。此驱动电路包括晶体管（T1，T2），连接于多个发光二极管（120）；恒流电路（151），连接于所述晶体管（T1，Τ2）；功率电阻（R2，R4），并联于所述晶体管（T1，Τ2）；以及功率开关（Q1，Q2），连接于所述晶体管（T1，Τ2）与所述功率电阻（R2，R4）之间，其中一切换信号是传送至所述功率开关（R2，R4），在一立体影像模式中所述切换信号的电位是高于在一平面影像模式中所述切换信号的电位。该驱动电路可应用于显示装置，并可在立体影像模式中提高背光模块的亮度。

Description

背光模块的驱动电路及其应用的显示装置 技术领域
本发明涉及一种背光模块的驱动电路及其应用的显示装置，特别是涉及一种可应用于切换2D/3D影像的背光模块的驱动电路及其应用的显示装置。
 背景技术
液晶显示器(Liquid Crystal Display，LCD)已被广泛应用于各种电子产品中，液晶显示器大部分为背光型液晶显示器，其是由液晶显示面板及背光模块(backlight module)所组成。背光模块可依照光源入射位置的不同分成侧向式入光(Side-light type)与直下式入光(Direct-light type)两种，藉以提供背光源至液晶显示面板。
由于发光二极管(Light-Emitting Diode，LED)具有低耗电量、低发热量、操作寿命长、耐撞击、体积小、反应速度快、以及可发出稳定波长的色光等良好光电特性，因而适合应用于背光模块的光源。
目前，已发展出可切换平面(2D)影像或立体(3D)影像的显示器。一般，可切换2D/3D影像的显示器包括2D面板和视差屏障(barrier)面板。当显示2D影像时，此视差屏障面板是呈透明状态，使得2D面板显示2D影像。当显示3D影像时，视差屏障面板可具有多个视差屏障，通过此些视差屏障来呈现出3D影像的效果。在3D影像模式中，由于视差屏障会减少面板的亮度，因而背光模块需提高亮度，以补偿亮度损失。
然而，在LED的驱动电路中，由于一般的驱动IC芯片所输出的驱动电流(如300mA)有限，而需使用多颗芯片，因而影响驱动电流的控制精度、设计复杂度，并增加驱动电路的成本。
故，有必要提供一种背光模块的驱动电路及其应用的显示装置，以解决现有技术所存在的问题。
 技术问题
本发明提供一种背光模块的驱动电路及其应用的显示装置，以解决驱动电路的输出电流的限制问题。
 技术解决方案
本发明的主要目的在于提供一种背光模块的驱动电路，驱动电路包括：晶体管，连接于多个发光二极管；恒流电路，连接于所述晶体管；功率电阻，并联于所述晶体管；以及功率开关，连接于所述晶体管与所述功率电阻之间，其中一切换信号是传送至所述功率开关，在一立体影像模式中所述切换信号的电位是高于在一平面影像模式中所述切换信号的电位。
本发明的另一目的在于提供一种背光模块的驱动电路，驱动电路包括：晶体管，连接于多个发光二极管；恒流电路，连接于所述晶体管；功率电阻，并联于所述晶体管；以及功率开关，连接于所述晶体管与所述功率电阻之间，其中一切换信号是传送至所述功率开关，在一立体影像模式中所述切换信号的电位是高于在一平面影像模式中所述切换信号的电位，在所述立体影像模式中所述切换信号的电位是高于2.5伏，在所述平面影像模式中所述切换信号的电位是低于0.8伏。
本发明的又一目的在于提供一种显示装置，显示装置包括显示面板及背光模块。背光模块包括：背板；多个发光二极管，设置于所述背板上；以及驱动电路，电性连接于所述发光二极管，其中所述驱动电路包括：晶体管，连接于发光二极管；恒流电路，连接于所述晶体管；功率电阻，并联于所述晶体管；以及功率开关，连接于所述晶体管与所述功率电阻之间，其中一切换信号是传送至所述功率开关，在一立体影像模式中所述切换信号的电位是高于在一平面影像模式中所述切换信号的电位。
在本发明的一实施例中，在所述立体影像模式中所述切换信号的电位是高于2.5伏。
在本发明的一实施例中，在所述立体影像模式中所述切换信号的电位是介于2.5伏与3.3伏之间。
在本发明的一实施例中，在所述平面影像模式中所述切换信号的电位是低于0.8伏。
在本发明的一实施例中，驱动电路还包括乘法器，用于将所述切换信号及一脉冲宽度调制信号进行相乘，并将相乘后的信号传送至所述功率开关。
在本发明的一实施例中，驱动电路还包括电阻，连接于晶体管。
在本发明的一实施例中，所述恒流电路包括稳压器及放大器，所述稳压器是连接于电源及所述放大器之间，所述放大器是连接于所述第一晶体管。
在本发明的一实施例中，所述稳压器为低压差线性稳压器。
在本发明的一实施例中，在所述立体影像模式中所述发光二极管所得到的电流为在平面影像模式中所述发光二极管所得到的电流的二倍。
 有益效果
本发明的背光模块的驱动电路及其应用的显示装置可简化驱动电路的设计，并可使用单一驱动IC芯片来确保驱动电流的控制精度，节省驱动电路的成本。
 附图说明
图1显示依照本发明的一实施例的显示装置的剖面示意图；以及
图2显示依照本发明的一实施例的驱动电路的电路图。
 本发明的最佳实施方式
以下各实施例的说明是参考附加的图式，用以例示本发明可用以实施的特定实施例。本发明所提到的方向用语，例如「上」、「下」、「前」、「后」、「左」、「右」、「内」、「外」、「侧面」等，仅是参考附加图式的方向。因此，使用的方向用语是用以说明及理解本发明，而非用以限制本发明。
在图中，结构相似的单元是以相同标号表示。
请参照图1，其显示依照本发明的一实施例的显示装置的剖面示意图。本实施例的驱动电路150可用以驱动背光模块100的多个发光二极管(Light-Emitting Diode，LED)120，这些发光二极管120可串联成一发光二极管串，以作为背光模块100的光源。此背光模块100可为侧向式入光或直下式入光，其相对于一显示面板101(例如液晶显示面板)来设置，而形成一显示装置(例如液晶显示装置)。
如图1所示，在本实施例中，此显示装置可依使用者的需求来切换为平面(2D)影像模式或立体(3D)影像模式，以分别显示2D或3D影像。此时，显示装置更包括视差屏障板102，显示面板101是用以显示2D影像，视差屏障板102可设置于显示面板110的一侧(出光侧)，用于在一3D影像模式中形成视差屏障效果，并通过此视差屏障板102来形成3D影像的效果。然不限此，在其它实施例中，可通过其它方式来形成视差屏障效果或3D影像效果。
如图1所示，在本实施例中，背光模块100可例如为直下式背光模块，其包括背板110、多个发光二极管(LED)120、电路板130、反射层140、驱动电路150及光学膜片160。背板110用以承载发光二极管120及电路板130，发光二极管120可设置于电路板130上，并通过电路板130来电性连接于驱动电路150，用以发光来提供光线至显示面板101。电路板130可为印刷电路板(Printed circuit board，PCB)或柔性印刷电路板(Flexible Printed Circuits，FPC)。反射层140是形成于发光二极管120的周围(例如形成于电路板130或背板110上)，用以反射发光二极管120的光线。驱动电路150可通过电路板130来电性连接于发光二极管120。光学膜片160是设置于发光二极管120上方，用以改善发光二极管120的发光均匀性或发光效率。
在另一实施例中，本发明的驱动电路亦可应用于侧向式入光的背光模块(未显示)。
请参照图2，其显示依照本发明的一实施例的驱动电路的电路图。本实施例的驱动电路150包括第一晶体管T1、第二晶体管T2、恒流电路151、第一功率开关Q1、第二功率开关Q2、电阻R1、R3、功率电阻R2、R4及乘法器152。晶体管T1及T2是连接于发光二极管120，恒流电路151是连接于晶体管T1及T2，功率电阻R2及R4是并联于晶体管T1及T2，功率开关Q1及Q2是分别连接于晶体管T1及T2与功率电阻R2及R4之间，乘法器152是连接于功率开关Q1及Q2。其中一切换信号可通过乘法器152来传送至所述功率开关，用于切换平面(2D)/立体(3D)的影像。以下，此切换信号可参照为2D/3D切换信号。
如图2所示，在本实施例中，晶体管T1及T2可为双载子晶体管(Bipolar Junction Transistor，BJT)或金氧半场效晶体管(Metal-Oxide- Semiconductor Field-Effect Transistor，MOSFET)。第一晶体管T1的集极可连接于第一发光二极管串121，第一晶体管T1的射极是连接于第一节点N1，第一晶体管T1的基极是连接于恒流电路151。第二晶体管T2的集极可连接于第二发光二极管串122，第二晶体管T2的射极是连接于第二节点N2，第二晶体管T2的基极是连接于恒流电路151。
如图2所示，在本实施例中，恒流电路151可为一恒流IC芯片，用于稳定发光二极管120的电流，使得发光二极管120可具有一致的电流。恒流电路151可包括稳压器153及放大器V1、V2，稳压器153例如为低压差线性稳压器(Low drop-out linear regulator)，其连接于电源VCC及放大器V1、V2之间。放大器V1是分别连接于第一晶体管T1的基极，放大器V2是分别连接于第二晶体管T2的基极，其中一脉冲宽度调制(PWM)信号是分别传送至放大器V1、V2。
如图2所示，在本实施例中，功率开关Q1及Q2例如为耗尽型N沟道金属氧化物半导体(NMOS)晶体管。第一功率开关Q1的漏极是连接于发光二极管120，第一功率开关Q1的源极是连接于功率电阻R2，第一功率开关Q1的栅极是连接于乘法器152。第二功率开关Q2的漏极是连接于发光二极管120，第二功率开关Q2的源极是连接于功率电阻R4，第二功率开关Q2的栅极是连接于乘法器152。电阻R3是连接于第二晶体管T2的射极与接地之间，功率电阻R2是连接于第一节点N1与第一功率开关Q1之间，使得功率电阻R2与第一功率开关Q1并联于第一晶体管T1。功率电阻R4是连接于第二节点N2与第二功率开关Q2之间，使得功率电阻R4与第二功率开关Q2并联于第二晶体管T2。
如图2所示，在本实施例中，乘法器152是用于将2D/3D切换信号及PWM信号进行相乘，并将相乘后的信号传送至功率开关Q1及Q2，以切换功率开关Q1及Q2。2D/3D切换信号可由本发明的显示装置的控制器(未显示)来提供，此PWM信号可由外部的系统端(未显示)所提供，并通过例如时序控制器(未显示)来传送至恒流电路151及乘法器152。
如图2所示，在2D影像模式中，2D/3D切换信号可在通过乘法器152的相乘后传送至功率开关Q1及Q2。此时，2D/3D切换信号为低电平信号，因而关闭功率开关Q1及Q2。因此，发光二极管120所得到的电流仅为流过晶体管T1及T2的电流。
如图1所示，在3D影像模式中，2D/3D切换信号可在通过乘法器152的相乘后传送至功率开关Q1及Q2。此时，2D/3D切换信号为高电平信号，因而开启功率开关Q1及Q2。因此，发光二极管120所得到的电流可为流过晶体管T1及T2以及功率电阻R2及R4的电流总和，而大幅地提高发光二极管120的驱动电流，使得发光二极管120在3D影像模式中大幅地提高亮度，避免显示装置的影像亮度在2D/3D影像模式中不一致。其中，在3D影像模式中发光二极管120所得到的电流可约为在2D影像模式中发光二极管120所得到的电流的二倍。
在本实施例中，在3D影像模式中所述2D/3D切换信号的电位是高于在2D影像模式中所述2D/3D切换信号的电位。其中在3D影像模式中所述2D/3D切换信号的电位可高于2.5伏，例如介于2.5伏与3.3伏之间。在2D影像模式中所述2D/3D切换信号的电位可低于0.8伏，例如介于0伏与0.8伏之间。
由上述可知，通过本发明的背光模块的驱动电路及其应用的显示装置，可使用简易的电路于可切换2D/3D显示装置的背光模块中，以提高在3D影像模式中的背光亮度，而不需增加驱动IC芯片，因而可简化驱动电路的设计，并可使用单一驱动IC芯片来确保驱动电流的控制精度，节省驱动电路的成本。
综上所述，虽然本发明已以优选实施例揭露如上，但上述优选实施例并非用以限制本发明，本领域的普通技术人员，在不脱离本发明的精神和范围内，均可作各种更动与润饰，因此本发明的保护范围以权利要求界定的范围为准。
 本发明的实施方式
工业实用性
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Claims (20)

  1. 一种背光模块的驱动电路，包括：
    晶体管，连接于多个发光二极管；
    恒流电路，连接于所述晶体管；
    功率电阻，并联于所述晶体管；以及
    功率开关，连接于所述晶体管与所述功率电阻之间，其中一切换信号是传送至所述功率开关，在一立体影像模式中所述切换信号的电位是高于在一平面影像模式中所述切换信号的电位，在所述立体影像模式中所述切换信号的电位是高于2.5伏，在所述平面影像模式中所述切换信号的电位是低于0.8伏。
  2. 根据权利要求1所述的驱动电路，其中在所述立体影像模式中所述切换信号的电位是介于2.5伏与3.3伏之间。
  3. 根据权利要求1所述的驱动电路，还包括乘法器，用于将所述切换信号及一脉冲宽度调制信号进行相乘，并将相乘后的信号传送至所述功率开关。
  4. 根据权利要求1所述的驱动电路，还包括电阻，连接于晶体管。
  5. 根据权利要求1所述的驱动电路，其中所述恒流电路包括稳压器及放大器，所述稳压器是连接于电源及所述放大器之间，所述放大器是连接于所述晶体管。
  6. 根据权利要求5所述的驱动电路，其中所述稳压器为低压差线性稳压器。
  7. 根据权利要求1所述的驱动电路，其中在所述立体影像模式中所述发光二极管所得到的电流为在平面影像模式中所述发光二极管所得到的电流的二倍。
  8. 一种背光模块的驱动电路，包括：
    晶体管，连接于多个发光二极管；
    恒流电路，连接于所述晶体管；
    功率电阻，并联于所述晶体管；以及
    功率开关，连接于所述晶体管与所述功率电阻之间，其中一切换信号是传送至所述功率开关，在一立体影像模式中所述切换信号的电位是高于在一平面影像模式中所述切换信号的电位。
  9. 根据权利要求8所述的驱动电路，其中在所述立体影像模式中所述切换信号的电位是高于2.5伏。
  10. 根据权利要求9所述的驱动电路，其中在所述立体影像模式中所述切换信号的电位是介于2.5伏与3.3伏之间。
  11. 根据权利要求8所述的驱动电路，其中在所述平面影像模式中所述切换信号的电位是低于0.8伏。
  12. 根据权利要求8所述的驱动电路，还包括乘法器，用于将所述切换信号及一脉冲宽度调制信号进行相乘，并将相乘后的信号传送至所述功率开关。
  13. 根据权利要求8所述的驱动电路，还包括电阻，连接于晶体管。
  14. 根据权利要求8所述的驱动电路，其中所述恒流电路包括稳压器及放大器，所述稳压器是连接于电源及所述放大器之间，所述放大器是连接于所述第一晶体管。
  15. 根据权利要求14所述的驱动电路，其中所述稳压器为低压差线性稳压器。
  16. 根据权利要求8所述的驱动电路，其中在所述立体影像模式中所述发光二极管所得到的电流为在平面影像模式中所述发光二极管所得到的电流的二倍。
  17. 一种显示装置，包括：
    显示面板；以及
    背光模块，包括：
    背板；
    多个发光二极管，设置于所述背板上；以及
    驱动电路，电性连接于所述发光二极管，其中所述驱动电路包括：
    晶体管，连接于所述发光二极管；
    恒流电路，连接于所述晶体管；
    功率电阻，并联于所述晶体管；以及
    功率开关，连接于所述晶体管与所述功率电阻之间，其中一切换信号是传送至所述功率开关，在一立体影像模式中所述切换信号的电位是高于在一平面影像模式中所述切换信号的电位。
  18. 根据权利要求17所述的显示装置，还包括视差屏障板，设置于所述显示面板的一侧。
  19. 根据权利要求17所述的显示装置，其中在所述立体影像模式中所述切换信号的电位是高于2.5伏。
  20. 根据权利要求17所述的显示装置，其中在所述平面影像模式中所述切换信号的电位是低于0.8伏。
PCT/CN2012/074972 2012-04-16 2012-05-02 背光模块的驱动电路及其应用的显示装置 WO2013155736A1 (zh)

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