WO2013125077A1 - Liquid-crystal display device - Google Patents

Liquid-crystal display device Download PDF

Info

Publication number
WO2013125077A1
WO2013125077A1 PCT/JP2012/073047 JP2012073047W WO2013125077A1 WO 2013125077 A1 WO2013125077 A1 WO 2013125077A1 JP 2012073047 W JP2012073047 W JP 2012073047W WO 2013125077 A1 WO2013125077 A1 WO 2013125077A1
Authority
WO
WIPO (PCT)
Prior art keywords
backlight
video
control
liquid crystal
glasses
Prior art date
Application number
PCT/JP2012/073047
Other languages
French (fr)
Japanese (ja)
Inventor
下田　裕紀
Original Assignee
シャープ株式会社
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 シャープ株式会社 filed Critical シャープ株式会社
Publication of WO2013125077A1 publication Critical patent/WO2013125077A1/en

Links

Images

Classifications

    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
    • G09G3/3406—Control of illumination source
    • 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
    • H04N13/332—Displays for viewing with the aid of special glasses or head-mounted displays [HMD]
    • H04N13/341—Displays for viewing with the aid of special glasses or head-mounted displays [HMD] using temporal multiplexing
    • 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
    • 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
    • H04N13/398—Synchronisation thereof; Control thereof
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B30/00—Optical systems or apparatus for producing three-dimensional [3D] effects, e.g. stereoscopic images
    • G02B30/20—Optical systems or apparatus for producing three-dimensional [3D] effects, e.g. stereoscopic images by providing first and second parallax images to an observer's left and right eyes
    • G02B30/22—Optical systems or apparatus for producing three-dimensional [3D] effects, e.g. stereoscopic images by providing first and second parallax images to an observer's left and right eyes of the stereoscopic type
    • G02B30/24—Optical systems or apparatus for producing three-dimensional [3D] effects, e.g. stereoscopic images by providing first and second parallax images to an observer's left and right eyes of the stereoscopic type involving temporal multiplexing, e.g. using sequentially activated left and right shutters
    • 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
    • G09G2320/00—Control of display operating conditions
    • G09G2320/06—Adjustment of display parameters
    • G09G2320/0626—Adjustment of display parameters for control of overall brightness
    • G09G2320/064—Adjustment of display parameters for control of overall brightness by time modulation of the brightness of the illumination source

Definitions

  • the present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device that controls lighting of a backlight that illuminates a liquid crystal panel in accordance with a video signal to be displayed.
  • liquid crystal display devices such as television receivers
  • those equipped with a 3D video display function are widespread.
  • 3D video in particular, left-eye video and right-eye video are alternately displayed for each frame, for example, and 3D display is performed by opening and closing a shutter equipped with 3D glasses in synchronization with the timing.
  • active shutter type There is a so-called active shutter type.
  • liquid crystal panels There are two types of liquid crystal panels: a so-called normal panel in which liquid crystal response performance is normal, and a panel in which liquid crystal response is faster than that of, for example, a normal panel and 3D display is performed by performing high-speed signal processing at 4 ⁇ speed (240 Hz) or higher.
  • a system using the normal panel described above tends to cause crosstalk in which images for different eyes are leaked as compared with a system using a panel having high-speed response, and 3D performance tends to deteriorate.
  • a technique for improving 3D performance such as crosstalk by controlling ON timing of active shutter 3D glasses as well as backlight lighting control is known. For example, when opening and closing the shutter of a liquid crystal shutter provided in frame sequential 3D glasses by pulse width modulation (PWM) control and switching the left and right shutters, the time to close both the left and right shutters is set. It is provided longer so that crosstalk due to synchro deviation does not occur.
  • PWM pulse width modulation
  • a technology for improving the quality of video expression and reducing power consumption in a liquid crystal display device equipped with a backlight a technology that dynamically changes the luminance of the backlight according to the feature amount of the video is used. ing.
  • This technique is also called active backlight.
  • a luminance control characteristic that defines a relationship between a predetermined feature amount representing the feature of the video and the light emission luminance of the backlight is determined in advance, and the feature amount is determined from the video signal for each frame of the video signal. Obtaining and controlling the light emission luminance of the backlight according to the obtained feature amount.
  • the feature amount for example, APL (Average Picture Level) indicating the average luminance of the video, the peak value of the video signal, or the like is used.
  • the above-described luminance control characteristic is determined as appropriate. For example, a luminance control characteristic that lowers the light emission luminance of the backlight as the feature amount decreases is determined. As a result, control is performed such as lowering the luminance of the backlight for darker images having a smaller feature amount, thereby suppressing black float of the images and improving the image quality.
  • the stereoscopic video device described in Patent Document 1 detects the frame frequency of the input video signal, and the phase of the synchronization signal according to the frame frequency. By adjusting the, the delay time of the switching signal of the left and right video to be transmitted to the active shutter 3D glasses is automatically adjusted according to the frame frequency. Thereby, it is said that the problem of crosstalk due to the inability to keep up with the switching speed of the liquid crystal shutter can be solved.
  • the video signal is displayed when the 3D video is displayed.
  • the feature amount decreases, the light emission luminance of the backlight decreases.
  • control for inserting a period for closing the shutter of the 3D glasses within one frame period in order to improve crosstalk when displaying 3D video as described above. Is done. That is, the period and timing for opening the shutter are set in advance within one frame period of video display, and the opening and closing of the shutter is controlled according to the setting.
  • the above shutter opening / closing is performed by PWM control.
  • the light emission luminance of the backlight is also modulated by changing the duty ratio of the pulse wave by the normal PWM control.
  • the duty ratio of PWM decreases and the lighting period in one frame becomes shorter.
  • 6 to 7 are diagrams for explaining states when the backlight lighting period and the shutter opening timing of the 3D glasses are shifted.
  • control is performed so that the shutter of the 3D glasses is opened only for a predetermined period within one frame period in order to avoid crosstalk.
  • 255 gradation white (8-bit expression) is displayed as a video signal. That is, the maximum gradation value of the video signal is displayed, and the video feature amount at this time becomes the maximum value regardless of whether it is APL or a peak value.
  • the backlight due to the action of the active backlight, the backlight emits light with the maximum light emission luminance in the luminance control characteristics.
  • FIG. 6 shows the light emission luminance level (BL) of the backlight by PWM control, the temporal change in the aperture ratio of the 3D glasses (glasses), and the temporal change in the luminance level of the video through the glasses (BL + glasses).
  • a time change (BL + glasses) of the luminance level of the image through the glasses is shown.
  • the aperture ratio of the glasses is 0%, which does not transmit light at all, and 100% transmits all light.
  • the aperture ratio when the aperture ratio is 0%, the shutter is closed, and when the aperture ratio is about 100%, it is also expressed as the shutter open.
  • the aperture ratio gradually increases from 0%, reaches 100%, and then drops rapidly to 0%.
  • the luminance level of the image through the glasses is an image luminance synthesized by the luminance of the backlight and the aperture ratio of the glasses. When viewing 3D, the user sees this video luminance.
  • the backlight is turned on / off by PWM control.
  • the light emission part of the backlight is controlled with a relatively high duty by the action of the active backlight.
  • the 3D glasses open the shutter for a certain period within one frame of the video. If the backlight of the 3D glasses is open when the backlight is lit (BL: Hi), the user views the image while the backlight lighting period and the shutter opening period overlap. be able to.
  • the backlight lighting period BL: Hi
  • the shutter opening period glasses: Hi
  • the video signal is almost black, and the video feature amount is almost the lowest value whether it is APL or the peak value.
  • the backlight due to the action of the active backlight, the backlight emits light with almost the minimum light emission luminance in the luminance control characteristics.
  • the backlight since the backlight is controlled to be turned on / off by PWM control, the light emission portion of the backlight is controlled with a low duty by the action of the active backlight, as indicated by BL.
  • Some backlight PWM control systems control the off period. In this case, the BL is turned off for a predetermined period from the timing when the BL is turned on, and then the BL is turned on.
  • the opening / closing timing of the shutter of the 3D glasses does not change, and the backlight lighting period is shortened by the active backlight. If the lighting period of the backlight and the shutter opening period do not overlap, the screen brightness through the glasses is extremely deteriorated, and the user cannot view the video.
  • the conventional backlight and 3D glasses control when the active backlight that changes the light emission luminance of the backlight according to the video feature amount is operated, the image by the 3D glasses is reduced when the light emission luminance of the backlight decreases. There is a problem that the visibility of the image becomes worse.
  • the present invention has been made in view of the above circumstances, and in a liquid crystal display device having a function of performing 3D display by an active shutter method and controlling the light emission luminance of a backlight according to a feature amount of a display image.
  • An object of the present invention is to provide a liquid crystal display device in which a 3D display screen can be surely seen even when the light emission luminance of a backlight changes during 3D display.
  • a first technical means of the present invention includes a liquid crystal panel, a backlight that illuminates the liquid crystal panel, and a control unit that controls display of the liquid crystal panel and lighting of the backlight.
  • the liquid crystal display device includes a 2D / 3D determination unit that determines whether a video to be displayed on the liquid crystal panel is a 2D video or a 3D video, and the control unit is a 2D video by the 2D / 3D determination unit. If determined, the backlight lighting control is executed by pulse width modulation control. If the 2D / 3D determination unit determines that the video is 3D video, the backlight lighting control is executed by voltage control. It is characterized by doing.
  • a second technical means is a liquid crystal display device including a liquid crystal panel, a backlight that illuminates the liquid crystal panel, and a control unit that controls display of the liquid crystal panel and lighting of the backlight.
  • a 2D / 3D determination unit that determines whether a video to be displayed is a 2D video or a 3D video, and the control unit controls lighting of the backlight when the 2D / 3D determination unit determines that the video is a 2D video Is executed by pulse width modulation control, and when the 2D / 3D determination unit determines that the image is 3D video, the backlight lighting control is executed by using both voltage control and pulse width modulation control. It is characterized by.
  • the third technical means includes, in the first or second technical means, 3D glasses including left and right shutters for viewing the liquid crystal panel, and a transmission unit that transmits a control signal to the 3D glasses,
  • the control unit alternately displays an image for the right eye and an image for the left eye, generates a control signal for opening and closing the shutter of the 3D glasses, and transmits the control signal from the transmission unit.
  • the control signal for opening and closing the shutter of the 3D glasses by pulse width modulation control is generated.
  • the present invention in a liquid crystal display device having a function of performing 3D display by an active shutter method and controlling the light emission luminance of the backlight according to the feature amount of the display image, the light emission of the backlight when performing the 3D display. Even when the luminance changes, the 3D display screen can be reliably recognized.
  • FIG. 10 is still another diagram for explaining the state of the lighting period of the backlight of 3D display and the opening timing of the shutter of the 3D glasses.
  • FIG. 10 is still another diagram for explaining the state of the lighting period of the backlight of 3D display and the opening timing of the shutter of the 3D glasses.
  • FIG. 1 is a diagram illustrating a configuration example of a main part of a liquid crystal display device according to the present invention, and is a diagram illustrating functional blocks related to video signal processing.
  • the tuner unit 1 selects and demodulates the broadcast signal received via the antenna, and outputs it to the input signal switching unit 3.
  • the external input unit 2 receives a signal from an external device such as a recorder input to the external input terminal, a video signal from a PC (Personal Computer) device input to the PC input terminal, a video signal input via a public network, or the like. input.
  • the input signal switching unit 3 appropriately switches and outputs the video signal output from the tuner unit 1 or the video signal output from the external input unit 2 in accordance with a user operation or the like on an operation input unit (not shown).
  • the AD conversion circuits 4 and 5 perform AD conversion and convert it into a digital signal.
  • the AD conversion circuit 4 is used when three-dimensional YC separation is performed, and the other AD conversion circuit 5 is used when three-dimensional YC separation is not performed.
  • a three-dimensional (3D) YC separation circuit 6 performs YC separation from the composite signal. In the three-dimensional YC separation, the correlation between the current frame image and the immediately preceding frame image is used to perform the correlation processing between frames, thereby efficiently and accurately performing the YC separation processing.
  • the video signal output from the 3DYC separation circuit 6 or the video signal output from the AD conversion circuit 5 is input to the color space conversion circuit 7.
  • the HDMI input unit 16 inputs a digital video signal transmitted through a high-definition multimedia interface (HDMI) interface and outputs the digital video signal to the color space conversion circuit 7.
  • the color space conversion circuit 7 performs color space conversion for converting a YUV video signal into an RGB signal.
  • the video signal subjected to the color space conversion is subjected to predetermined gamma correction by the gamma correction circuit 8 and output to the panel control unit 9.
  • the panel control unit 9 outputs a video signal as a signal that can be displayed on the liquid crystal panel 10 and controls the display of the liquid crystal panel 10.
  • the input video signal is a 3D video
  • the video signal input to the liquid crystal panel 10 is such that a right-eye video and a left-eye video are alternately displayed for each frame.
  • the 2D / 3D determination circuit unit 11 corresponds to the 2D / 3D determination unit of the present invention, confirms the format of the input video signal, and determines whether the input video signal is 2D video or 3D video.
  • the determination result is output to the system control unit 12.
  • the system control unit 12 controls a backlight control unit 13 that performs lighting control of the backlight 14 and a glasses control unit 15 that performs shutter opening / closing control of externally connected 3D glasses.
  • the control unit of the present invention is realized by the system control unit 12, the backlight control unit 13, and the glasses control unit 15.
  • the backlight 14 illuminates the liquid crystal panel 10 to modulate and display the image displayed on the liquid crystal panel 10.
  • the backlight 14 for example, a plurality of LEDs (LightmEmitting Diode) arranged in a matrix is used.
  • the system control unit 12 controls the glasses control unit 15 to transmit a control signal for controlling the shutter opening / closing of the 3D glasses.
  • the 3D glasses include left-eye and right-eye shutters, and control the opening and closing of the left-eye shutter and the right-eye shutter according to a control signal transmitted from the glasses control unit 15. This opening / closing control is performed by PWM control. With this control signal, the 3D glasses control the opening and closing of the left-eye shutter and the right-eye shutter in accordance with the right-eye video and the left-eye video displayed on the liquid crystal panel 10 so that the user can visually recognize the 3D video. I can do it.
  • the shutter for the left eye and the shutter for the right eye are constituted by, for example, a liquid crystal shutter that turns on / off the shutter function by the operation of liquid crystal.
  • the system control unit 12 has an active backlight function that is a function of controlling the light emission luminance of the backlight 14 according to the feature amount of the video signal.
  • a luminance control characteristic that defines the relationship between the feature amount representing a predetermined feature of the video and the light emission luminance of the backlight is determined in advance, and the feature amount is set for each frame of the video signal.
  • the light emission brightness of the backlight 14 is controlled in accordance with the acquired feature amount.
  • the feature amount for example, APL (Average Picture Level) indicating the average luminance of the video, the peak value of the video signal, or the like is used.
  • the luminance control characteristic can be determined as appropriate.
  • the luminance control characteristic is set such that the emission luminance of the backlight decreases as the feature amount decreases.
  • the darker video having a smaller feature amount reduces the backlight emission luminance, thereby performing control such as suppressing black floating of the video and improving the video quality.
  • the system control unit 12 acquires the above-described feature amount from the video signal, and outputs a dimming signal that determines the light emission luminance of the backlight 14 to the backlight control unit 13 according to a predetermined luminance control characteristic.
  • the backlight control unit 13 controls the light emission luminance of the backlight 14 according to the input dimming signal.
  • the backlight 14 has the lighting control function of both the PWM control and the voltage control, and switches these lighting control methods according to 2D / 3D.
  • the lighting control of the backlight 14 is controlled depending on whether the 2D / 3D determination circuit unit 11 determines that the format of the input video signal is 2D or 3D. change. Specifically, when the 2D / 3D determination circuit unit 11 determines that the input video signal is a 2D video, the system control unit 12 controls the backlight control unit 13 to turn on the backlight 14 by PWM. To order.
  • the system control unit 12 controls the backlight control unit 13 to turn on the backlight 14 by voltage control. Command.
  • the backlight 14 is lit at a constant level according to the dimming setting, so that the active backlight operates when displaying 3D video, and the light emission luminance of the backlight decreases. Even so, it is possible to solve the problem that the lighting period of the backlight and the opening period of the shutter of the 3D glasses are shifted to make the video invisible.
  • the backlight control unit 13 When performing dimming control when displaying 2D video by PWM, the backlight control unit 13 receives a dimming signal from the system control unit 12 and controls the light emission luminance of the backlight 14 by PWM modulation.
  • dimming is performed by changing the ON / OFF duty ratio of the switch element while keeping the voltage applied to the LED of the backlight 14 constant.
  • PWM modulation for driving the LED, the amount of current flowing through the LED is changed without changing the peak value of the current flowing through the LED.
  • the brightness of the LED is determined by the amount of current flowing through the LED, and the larger the duty ratio of the dimming PWM signal, the higher the emission luminance of the backlight 14.
  • the voltage applied to the LED of the backlight 14 is increased or decreased, and the brightness is changed by changing the peak value of the current flowing through the LED.
  • the voltage for controlling the brightness of the LED (the amount of current flowing through the LED) is made constant, and the backlight 14 is caused to emit light with the light emission luminance corresponding to the voltage. If the voltage for such constant voltage control is increased, the backlight 14 can be brightened.
  • 2 to 3 are diagrams for explaining the state of the lighting period of the 3D display backlight and the opening timing of the shutter of the 3D glasses.
  • control is performed so that the shutter of the 3D glasses is opened only for a predetermined period within one frame period in order to avoid crosstalk. To do.
  • 255 gradation white (8-bit representation) is displayed as a video signal. That is, the maximum gradation value of the video signal is displayed, and the video feature amount becomes the maximum value regardless of whether it is APL or peak value.
  • the backlight emits light with the maximum light emission luminance in the luminance control characteristics.
  • the lighting brightness level (BL) of the backlight by voltage control, the temporal change of the aperture ratio of the 3D glasses (glasses), and the temporal change of the luminance level of the video through the glasses (BL + glasses) are shown.
  • the aperture ratio of the glasses is 0%, which does not transmit light at all, and 100% transmits all light.
  • the aperture ratio gradually increases from 0%, reaches 100%, and then drops rapidly to 0%.
  • the luminance level of the image through the glasses is an image luminance synthesized by the luminance of the backlight and the aperture ratio of the glasses. When viewing 3D, the user sees this video luminance.
  • the backlight control unit 13 adjusts the backlight 14 by voltage control according to the control of the system control unit 12. Perform light control.
  • the light emission part of the backlight is controlled with a relatively high voltage by the action of the active backlight, but the backlight 14 is controlled to emit light with a constant voltage. Within the frame period, the backlight 14 continues to emit light at a constant level.
  • the 3D glasses open the shutter for a certain period within one frame of the image, but the backlight 14 is lit at a certain level, so the backlight 14 is turned on when the shutter of the 3D glasses is open. Since the backlight 14 does not turn off and the lighting period of the backlight 14 and the shutter opening period always overlap, the user can surely view the 3D image through the glasses.
  • the video signal displays one gradation white (8-bit expression). That is, the video is almost black, and the video feature amount is almost the lowest value whether it is APL or the peak value.
  • the backlight due to the action of the active backlight, the backlight emits light with almost the minimum light emission luminance in the luminance control characteristics.
  • the backlight 14 controls the light emission portion of the backlight at a low voltage by the action of the active backlight.
  • the light emission luminance of the backlight is reduced, but the backlight is not turned off when the shutter of the 3D glasses is open, and the lighting period of the backlight 14 and the opening period of the shutter are Since they always overlap, the user can surely view the 3D image through the glasses.
  • the liquid crystal display device of the present invention it is detected whether the video signal to be displayed is a 2D video signal or a 3D video signal, and when the 2D video is displayed, the lighting control of the backlight 14 is pulse width modulated. (PWM)
  • PWM pulse width modulated.
  • the lighting control of the backlight 14 is switched to voltage control when displaying a 3D video.
  • FIGS. 4 to 5 are diagrams for explaining other examples of backlight control during 3D display, and show the lighting period of the backlight for 3D display and the opening timing of the shutter of the 3D glasses.
  • the lighting control of the backlight 14 is switched from the PWM control to the voltage control so that the light emission luminance of the backlight becomes a constant level.
  • the light emission luminance of the backlight 14 is controlled by using both PWM and voltage control, and the light emission luminance level is changed without changing the lighting duty ratio. Change by voltage control.
  • the shutter of the 3D glasses is set to a predetermined period within one frame period in order to avoid crosstalk. It shall be controlled to open.
  • 255 gradation white (8-bit expression) is displayed as a video signal. That is, the maximum gradation value of the video signal is displayed, and the video feature amount becomes the maximum value regardless of whether it is APL or peak value.
  • the backlight due to the action of the active backlight, the backlight emits light with the maximum light emission luminance in the luminance control characteristics.
  • the lighting brightness level (BL) of the backlight by PWM control, the temporal change in the aperture ratio of the 3D glasses (glasses), and the temporal change in the luminance level of the video through the glasses (BL + glasses) are shown. Yes. In this case, the aperture ratio of the 3D glasses gradually increases from 0%, reaches 100%, and then drops rapidly to 0%.
  • the backlight uses both PWM control and voltage control.
  • the backlight control unit 13 uses the PWM control and the voltage control in combination with the backlight 14 in accordance with the control of the system control unit 12. Dimming control is performed.
  • the backlight is caused to emit light with a relatively high light emission luminance by the action of the active backlight.
  • the light emission of the backlight is controlled at a specific duty ratio by PWM control.
  • the backlight LED is caused to emit light at a constant voltage.
  • the brightness of the LED is determined by the amount of current flowing through the LED, but the desired luminance of the backlight is obtained by combining the peak value of the LED current by controlling the voltage applied to the LED and the duty ratio by PWM control. Control to obtain
  • 3D glasses open the shutter only for a certain period within one frame of video. If the backlight of the 3D glasses is open when the backlight is lit (BL: Hi), the user views the image while the backlight lighting period and the shutter opening period overlap. be able to. In this example, in the BL + glasses, since there is an overlapping part of the backlight lighting period (BL: Hi) and the shutter opening period (glasses: Hi), the user can visually recognize the image at the overlapping part. .
  • the duty ratio is increased and the voltage is lowered to obtain the desired light emission luminance, the backlight lighting period becomes longer, and the overlapping part with the shutter opening period of the glasses is further increased. It becomes easy.
  • the screen brightness when the shutter is open is relatively dark. Therefore, the optimum duty ratio and voltage value are determined by the balance between the two.
  • the video signal is displayed with one gradation of white (8-bit expression). That is, the video is almost black, and the video feature amount is almost the lowest value whether it is APL or the peak value.
  • the backlight due to the action of the active backlight, the backlight emits light with almost the minimum light emission luminance in the luminance control characteristics.
  • the backlight 14 is controlled by PWM control and voltage control, the voltage is lowered to control the light emission luminance of the backlight while maintaining the duty ratio by the PWM control.
  • the current peak value to the LED decreases due to the voltage drop and the light emission luminance of the backlight decreases, but the duty ratio does not change, so the overlap between the lighting period of the backlight 14 and the shutter opening period is maintained. Even if the light emission luminance of the backlight decreases, the user can surely view the 3D image through the glasses.
  • the voltage applied to the LED is changed while the duty ratio is always kept constant, but the duty ratio may not always be constant.
  • the duty ratio is slightly reduced and the voltage is also reduced at the same time, so that the reduction in brightness due to the voltage drop is suppressed while maintaining the overlap with the shutter opening period. It may be.
  • the duty ratio of the PWM control and the voltage value of the voltage control optimum conditions can be selected according to the timing of opening / closing control of the shutter of the glasses.
  • the liquid crystal display device of the present invention it is detected whether the video signal to be displayed is a 2D video signal or a 3D video signal, and when the 2D video is displayed, the lighting control of the backlight 14 is pulse width modulated.
  • the lighting control of the backlight 14 is switched to the combined use of the PWM control and the voltage control.
  • SYMBOLS 1 Tuner part, 2 ... External input part, 3 ... Input signal switching part, 4, 5 ... AD conversion circuit, 6 ... 3DYC separation circuit, 7 ... Color space conversion circuit, 8 ... Gamma correction circuit, 9 ...
  • Panel control part DESCRIPTION OF SYMBOLS 10 ... Liquid crystal panel, 11 ... 2D / 3D determination circuit part, 12 ... System control part, 13 ... Backlight control part, 14 ... Backlight, 15 ... Glasses control part, 16 ... HDMI input part.

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Physics & Mathematics (AREA)
  • Computer Hardware Design (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Liquid Crystal (AREA)
  • Testing, Inspecting, Measuring Of Stereoscopic Televisions And Televisions (AREA)
  • Liquid Crystal Display Device Control (AREA)
  • Control Of Indicators Other Than Cathode Ray Tubes (AREA)
  • Transforming Electric Information Into Light Information (AREA)

Abstract

Provided is a liquid-crystal display device having a function with which a 3-D display is carried out with an active shutter scheme, and whereby the emitted light brightness of a backlight is controlled according to the feature quantity of display video, with which reliable visual recognition of a 3-D display screen is possible even if the emitted light brightness of the backlight changes when the 3-D display is carried out. A liquid-crystal display device comprises a 2-D/3-D determination circuit unit (11) which determines whether video which is being displayed on a liquid-crystal panel (10) is 2-D video or 3-D video. If the video is determined to be 2-D video by the 2-D/3-D video determination unit (11), a system control unit (12) executes, by a pulse width modulation control, a lighting control of a backlight (14), and if the video is determined to be 3-D video by the 2-D/3-D determination circuit unit (11), the system control unit (12) executes, by either a voltage control or a combination of the PWM control and the voltage control, the lighting control of the backlight (14).

Description

液晶表示装置Liquid crystal display
　本発明は、液晶表示装置、より詳細には、表示すべき映像信号に応じて液晶パネルを照明するバックライトの点灯制御を行う液晶表示装置に関する。 The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device that controls lighting of a backlight that illuminates a liquid crystal panel in accordance with a video signal to be displayed.
　テレビ受像機等の液晶表示装置においては、３Ｄ映像の表示機能が搭載されているものが普及している。３Ｄ映像の表示においては、特に左目用の映像と右目用の映像を例えば１フレームごとに交互に表示し、そのタイミングに同期して３Ｄメガネに装備されたシャッターを開閉することで３Ｄ表示を行う、所謂アクティブシャッター方式のものがある。 In liquid crystal display devices such as television receivers, those equipped with a 3D video display function are widespread. In the display of 3D video, in particular, left-eye video and right-eye video are alternately displayed for each frame, for example, and 3D display is performed by opening and closing a shutter equipped with 3D glasses in synchronization with the timing. There is a so-called active shutter type.
　液晶パネルでは、液晶の応答性能が通常の所謂ノーマルパネルと、例えばノーマルパネルよりも液晶の応答性が速く、４倍速（２４０Ｈｚ）以上の高速信号処理を行って３Ｄ表示を行うパネルとがある。例えば上記のノーマルパネルを用いたシステムは、高速応答性を有するパネルを用いたシステムに比して、左右異なる目用の映像が漏れるクロストークが生じやすく、３Ｄ性能が悪化する傾向にある。 There are two types of liquid crystal panels: a so-called normal panel in which liquid crystal response performance is normal, and a panel in which liquid crystal response is faster than that of, for example, a normal panel and 3D display is performed by performing high-speed signal processing at 4 × speed (240 Hz) or higher. For example, a system using the normal panel described above tends to cause crosstalk in which images for different eyes are leaked as compared with a system using a panel having high-speed response, and 3D performance tends to deteriorate.
　このような問題を改善するために、バックライトの点灯制御だけでなく、アクティブシャッター方式の３ＤメガネのＯＮタイミングを制御してクロストーク等の３Ｄ性能を改善する技術が知られている。例えばフレームシーケンシャル方式の３Ｄメガネに設けられた液晶シャッターをパルス幅変調（ＰＷＭ（pulse width modulation））制御によってシャッターの開閉制御を行い、左右のシャッターを切り換えるときに、左右両方のシャッターを閉じる時間を長めに設け、シンクロずれによるクロストークが生じないようにしている。 In order to improve such a problem, a technique for improving 3D performance such as crosstalk by controlling ON timing of active shutter 3D glasses as well as backlight lighting control is known. For example, when opening and closing the shutter of a liquid crystal shutter provided in frame sequential 3D glasses by pulse width modulation (PWM) control and switching the left and right shutters, the time to close both the left and right shutters is set. It is provided longer so that crosstalk due to synchro deviation does not occur.
　一方、バックライトを備えた液晶表示装置における映像表現の品位を向上させるとともに、消費電力を低減させる技術に関して、映像の特徴量に応じてバックライトの発光輝度を動的に変化させる技術が用いられている。この技術は、アクティブバックライトとも呼ばれる。アクティブバックライトでは、映像の特徴を表す所定の特徴量と、バックライトの発光輝度との関係を規定する輝度制御特性を予め定めておき、映像信号のフレームごとにその映像信号から上記特徴量を取得し、取得した特徴量に応じてバックライトの発光輝度を制御する。特徴量としては、例えば映像の平均輝度を示すＡＰＬ（Average Picture Level）や、映像信号のピーク値などが用いられる。 On the other hand, as a technology for improving the quality of video expression and reducing power consumption in a liquid crystal display device equipped with a backlight, a technology that dynamically changes the luminance of the backlight according to the feature amount of the video is used. ing. This technique is also called active backlight. In the active backlight, a luminance control characteristic that defines a relationship between a predetermined feature amount representing the feature of the video and the light emission luminance of the backlight is determined in advance, and the feature amount is determined from the video signal for each frame of the video signal. Obtaining and controlling the light emission luminance of the backlight according to the obtained feature amount. As the feature amount, for example, APL (Average Picture Level) indicating the average luminance of the video, the peak value of the video signal, or the like is used.
　上記の輝度制御特性は、適宜定められるが、例えば、特徴量が小さくなるほどバックライトの発光輝度を低下させるような輝度制御特性が定められる。これにより、特徴量の小さい暗い映像ほどバックライトの発光輝度を低下させることで、映像の黒浮きを抑えて映像品位を高くするなどの制御が行われる。 The above-described luminance control characteristic is determined as appropriate. For example, a luminance control characteristic that lowers the light emission luminance of the backlight as the feature amount decreases is determined. As a result, control is performed such as lowering the luminance of the backlight for darker images having a smaller feature amount, thereby suppressing black float of the images and improving the image quality.
　３Ｄ映像表示時のバックライト光源の点灯制御の技術に関して、例えば、特許文献１に記載された立体映像装置は、入力された映像信号のフレーム周波数を検出し、フレーム周波数に応じて同期信号の位相を調整することにより、フレーム周波数に応じてアクティブシャッター方式の３Ｄメガネに送信する左右映像の切替え信号の遅延時間を自動的に調整する。これにより、液晶シャッターの切替え速度が追いつかないことによるクロストークの問題を解消できるとされている。 With regard to the lighting control technology of the backlight light source at the time of 3D video display, for example, the stereoscopic video device described in Patent Document 1 detects the frame frequency of the input video signal, and the phase of the synchronization signal according to the frame frequency. By adjusting the, the delay time of the switching signal of the left and right video to be transmitted to the active shutter 3D glasses is automatically adjusted according to the frame frequency. Thereby, it is said that the problem of crosstalk due to the inability to keep up with the switching speed of the liquid crystal shutter can be solved.
特開２０１０－２６８０３６号公報JP 2010-268036 A
　上記のノーマルパネルとアクティブシャッター方式の３Ｄメガネとを使用して３Ｄ映像を表示する液晶表示装置において、アクティブバックライトの機能が動作している場合、３Ｄ映像を表示しているときに映像信号の特徴量が低下すると、バックライトの発光輝度が低下する。
　このとき、ノーマルパネルを用いた液晶表示装置の場合、上記のように３Ｄ映像を表示しているときのクロストークを改善するため、１フレーム期間内に３Ｄメガネのシャッターを閉じる期間を挿入する制御が行われる。つまり映像表示の１フレーム期間内に、シャッターが開く期間とタイミングが予め設定され、その設定に従ってシャッターの開閉が制御される。 In the liquid crystal display device that displays 3D video using the normal panel and the active shutter 3D glasses, when the active backlight function is operating, the video signal is displayed when the 3D video is displayed. When the feature amount decreases, the light emission luminance of the backlight decreases.
At this time, in the case of a liquid crystal display device using a normal panel, control for inserting a period for closing the shutter of the 3D glasses within one frame period in order to improve crosstalk when displaying 3D video as described above. Is done. That is, the period and timing for opening the shutter are set in advance within one frame period of video display, and the opening and closing of the shutter is controlled according to the setting.
　上記のシャッター開閉はＰＷＭ制御によって行われるが、一方バックライトの発光輝度についても、通常ＰＷＭ制御により、パルス波のデューティ比を変化させて発光輝度を変調している。この場合、アクティブバックライトが動作してバックライトの発光輝度が低下すると、ＰＷＭのデューティ比が低下し、１フレームにおける点灯期間が短くなっていく。このときに、３Ｄメガネのシャッターが開くタイミングと、バックライトが発光するタイミングとがずれてしまうと、バックライトが発光しているときにシャッターが閉じてしまい、メガネ越しの輝度が極端に低下して映像が視認できなくなる、という問題が生じる。以下にこの現象を具体的に説明する。 The above shutter opening / closing is performed by PWM control. On the other hand, the light emission luminance of the backlight is also modulated by changing the duty ratio of the pulse wave by the normal PWM control. In this case, when the active backlight operates and the light emission luminance of the backlight decreases, the duty ratio of PWM decreases and the lighting period in one frame becomes shorter. At this time, if the timing of opening the shutter of the 3D glasses deviates from the timing of emitting the backlight, the shutter closes when the backlight emits light, and the brightness over the glasses decreases extremely. This causes a problem that the video cannot be viewed. This phenomenon will be specifically described below.
　図６～図７は、バックライトの点灯期間と３Ｄメガネのシャッターの開タイミングがずれるときの状態を説明するための図である。
　ここでは、液晶応答特性がそれほど高速ではないノーマルパネルを用いて３Ｄ表示を行う場合、クロストークを避けるために３Ｄメガネのシャッターを１フレーム期間内の所定期間だけ開けるように制御するものとする。 6 to 7 are diagrams for explaining states when the backlight lighting period and the shutter opening timing of the 3D glasses are shifted.
Here, when 3D display is performed using a normal panel whose liquid crystal response characteristics are not so fast, control is performed so that the shutter of the 3D glasses is opened only for a predetermined period within one frame period in order to avoid crosstalk.
　図６の例は、映像信号として２５５階調の白（８ビット表現）が表示されているものとする。つまり、映像信号の最大階調値が表示され、このときの映像特徴量は、ＡＰＬであってもピーク値であっても最大値になる。この場合、アクティブバックライトの作用により、バックライトは輝度制御特性における最大の発光輝度で発光される。 In the example of FIG. 6, it is assumed that 255 gradation white (8-bit expression) is displayed as a video signal. That is, the maximum gradation value of the video signal is displayed, and the video feature amount at this time becomes the maximum value regardless of whether it is APL or a peak value. In this case, due to the action of the active backlight, the backlight emits light with the maximum light emission luminance in the luminance control characteristics.
　図６では、ＰＷＭ制御によるバックライトの発光輝度レベル（ＢＬ）と、３Ｄメガネの開口率の時間変化（メガネ）と、メガネを通しての映像の輝度レベルの時間変化（ＢＬ＋メガネ）とが示されている。メガネを通しての映像の輝度レベルの時間変化（ＢＬ＋メガネ）とが示されている。メガネの開口率は０％で全く光を通さず、１００％で光をすべて通す。以下、説明上、開口率０％時をシャッター閉、開口率が１００％程度をシャッター開とも表現する。図６においては開口率は０％から徐々に上がり、１００％になった後、急激に０％に落とす特性としている。メガネを通しての映像の輝度レベルについてはバックライトの輝度とメガネの開口率によって合成された映像輝度となる。３Ｄ視聴時、ユーザは、この映像輝度を見ることになる。 FIG. 6 shows the light emission luminance level (BL) of the backlight by PWM control, the temporal change in the aperture ratio of the 3D glasses (glasses), and the temporal change in the luminance level of the video through the glasses (BL + glasses). Yes. A time change (BL + glasses) of the luminance level of the image through the glasses is shown. The aperture ratio of the glasses is 0%, which does not transmit light at all, and 100% transmits all light. In the following description, when the aperture ratio is 0%, the shutter is closed, and when the aperture ratio is about 100%, it is also expressed as the shutter open. In FIG. 6, the aperture ratio gradually increases from 0%, reaches 100%, and then drops rapidly to 0%. The luminance level of the image through the glasses is an image luminance synthesized by the luminance of the backlight and the aperture ratio of the glasses. When viewing 3D, the user sees this video luminance.
　上記のように、バックライトはＰＷＭ制御で点灯・消灯が制御される。ここでは、高階調の映像信号が表示されているため、アクティブバックライトの作用により比較的高いデューティでバックライトの発光部分が制御される。
　３Ｄメガネは、映像の１フレーム内で一定期間だけシャッターを開放する。バックライトが点灯しているときに（ＢＬ：Ｈｉ）、３Ｄメガネのシャッターが開となっていれば、ユーザはそのバックライトの点灯期間とシャッターの開放期間とが重複する間、映像を視認することができる。この例の場合、ＢＬ＋メガネでは、バックライトの点灯期間（ＢＬ：Ｈｉ）と、シャッターの開放期間（メガネ：Ｈｉ）の重複部分があるため、ユーザはその重複部分で映像を視認することができる。 As described above, the backlight is turned on / off by PWM control. Here, since a high gradation video signal is displayed, the light emission part of the backlight is controlled with a relatively high duty by the action of the active backlight.
The 3D glasses open the shutter for a certain period within one frame of the video. If the backlight of the 3D glasses is open when the backlight is lit (BL: Hi), the user views the image while the backlight lighting period and the shutter opening period overlap. be able to. In this example, in the BL + glasses, since there is an overlapping part of the backlight lighting period (BL: Hi) and the shutter opening period (glasses: Hi), the user can visually recognize the image at the overlapping part. .
　図７の例は、映像信号として１階調の白（８ビット表現）が表示されているものとする。つまり、映像はほぼ黒であり、映像特徴量は、ＡＰＬであってもピーク値であってもほぼ最低値になる。この場合、アクティブバックライトの作用により、バックライトは輝度制御特性におけるほぼ最少の発光輝度で発光される。このときバックライトはＰＷＭ制御で点灯・消灯が制御されるためＢＬに示されるように、アクティブバックライトの作用により低いデューティでバックライトの発光部分が制御される。バックライトＰＷＭ制御方式によっては、オフ期間を制御するものもある。その際は、ＢＬのオンからオフへのタイミングから所定の期間オフを継続しその後ＢＬをオンする。 In the example of FIG. 7, it is assumed that one gradation of white (8-bit representation) is displayed as the video signal. That is, the video is almost black, and the video feature amount is almost the lowest value whether it is APL or the peak value. In this case, due to the action of the active backlight, the backlight emits light with almost the minimum light emission luminance in the luminance control characteristics. At this time, since the backlight is controlled to be turned on / off by PWM control, the light emission portion of the backlight is controlled with a low duty by the action of the active backlight, as indicated by BL. Some backlight PWM control systems control the off period. In this case, the BL is turned off for a predetermined period from the timing when the BL is turned on, and then the BL is turned on.
　ここでは、３Ｄメガネのシャッターの開閉タイミングは変化せず、アクティブバックライトによってバックライトの点灯期間が短くなる。そしてバックライトの点灯期間とシャッターの開放期間とが重複しなければ、メガネ越しの画面輝度が極端に悪化し、ユーザからは映像を視認することができなくなる。
　つまり、従来のバックライトと３Ｄメガネの制御において、映像特徴量に応じてバックライトの発光輝度を変化させるアクティブバックライトを動作させると、バックライトの発光輝度が低下したときに、３Ｄメガネによる映像の視認性が悪化してしまう、という問題がある。 Here, the opening / closing timing of the shutter of the 3D glasses does not change, and the backlight lighting period is shortened by the active backlight. If the lighting period of the backlight and the shutter opening period do not overlap, the screen brightness through the glasses is extremely deteriorated, and the user cannot view the video.
In other words, in the conventional backlight and 3D glasses control, when the active backlight that changes the light emission luminance of the backlight according to the video feature amount is operated, the image by the 3D glasses is reduced when the light emission luminance of the backlight decreases. There is a problem that the visibility of the image becomes worse.
　本発明は、上述のごとき実情に鑑みてなされたもので、アクティブシャッター方式で３Ｄ表示を行う機能を有し、表示映像の特徴量に応じてバックライトの発光輝度を制御する液晶表示装置において、３Ｄ表示を行う際にバックライトの発光輝度が変化しても３Ｄ表示画面を確実に視認できるようにした液晶表示装置を提供することを目的とする。 The present invention has been made in view of the above circumstances, and in a liquid crystal display device having a function of performing 3D display by an active shutter method and controlling the light emission luminance of a backlight according to a feature amount of a display image. An object of the present invention is to provide a liquid crystal display device in which a 3D display screen can be surely seen even when the light emission luminance of a backlight changes during 3D display.
　上記課題を解決するために、本発明の第１の技術手段は、液晶パネルと、該液晶パネルを照明するバックライトと、前記液晶パネルの表示及び前記バックライトの点灯を制御する制御部とを備えた液晶表示装置において、前記液晶パネルに表示させる映像が２Ｄ映像か３Ｄ映像かを判定する２Ｄ／３Ｄ判定部を備え、前記制御部は、前記２Ｄ／３Ｄ判定部によって２Ｄ映像であることが判定された場合、前記バックライトの点灯制御を、パルス幅変調制御によって実行し、前記２Ｄ／３Ｄ判定部によって３Ｄ映像であることが判定された場合、前記バックライトの点灯制御を電圧制御によって実行することを特徴としたものである。 In order to solve the above problems, a first technical means of the present invention includes a liquid crystal panel, a backlight that illuminates the liquid crystal panel, and a control unit that controls display of the liquid crystal panel and lighting of the backlight. The liquid crystal display device includes a 2D / 3D determination unit that determines whether a video to be displayed on the liquid crystal panel is a 2D video or a 3D video, and the control unit is a 2D video by the 2D / 3D determination unit. If determined, the backlight lighting control is executed by pulse width modulation control. If the 2D / 3D determination unit determines that the video is 3D video, the backlight lighting control is executed by voltage control. It is characterized by doing.
　第２の技術手段は、液晶パネルと、該液晶パネルを照明するバックライトと、前記液晶パネルの表示及び前記バックライトの点灯を制御する制御部とを備えた液晶表示装置において、前記液晶パネルに表示させる映像が２Ｄ映像か３Ｄ映像かを判定する２Ｄ／３Ｄ判定部を備え、前記制御部は、前記２Ｄ／３Ｄ判定部によって２Ｄ映像であることが判定された場合、前記バックライトの点灯制御を、パルス幅変調制御によって実行し、前記２Ｄ／３Ｄ判定部によって３Ｄ映像であることが判定された場合、前記バックライトの点灯制御を電圧制御とパルス幅変調制御を併用することによって実行することを特徴としたものである。 A second technical means is a liquid crystal display device including a liquid crystal panel, a backlight that illuminates the liquid crystal panel, and a control unit that controls display of the liquid crystal panel and lighting of the backlight. A 2D / 3D determination unit that determines whether a video to be displayed is a 2D video or a 3D video, and the control unit controls lighting of the backlight when the 2D / 3D determination unit determines that the video is a 2D video Is executed by pulse width modulation control, and when the 2D / 3D determination unit determines that the image is 3D video, the backlight lighting control is executed by using both voltage control and pulse width modulation control. It is characterized by.
　第３の技術手段は、第１または２の技術手段において、前記液晶パネルを視認するための左右のシャッターを備える３Ｄメガネと、前記３Ｄメガネに制御信号を送信する送信部とを有し、前記制御部は、右目用の画像と左目用の画像を交互に表示するとともに、前記３Ｄメガネの前記シャッターを開閉する制御信号を生成して前記送信部から送信させ、前記制御部は、前記３Ｄ映像を前記液晶パネルに表示させる際に、前記３Ｄメガネの前記シャッターをパルス幅変調制御によって開閉させる前記制御信号を生成することを特徴としたものである。 The third technical means includes, in the first or second technical means, 3D glasses including left and right shutters for viewing the liquid crystal panel, and a transmission unit that transmits a control signal to the 3D glasses, The control unit alternately displays an image for the right eye and an image for the left eye, generates a control signal for opening and closing the shutter of the 3D glasses, and transmits the control signal from the transmission unit. When the image is displayed on the liquid crystal panel, the control signal for opening and closing the shutter of the 3D glasses by pulse width modulation control is generated.
　本発明によれば、アクティブシャッター方式で３Ｄ表示を行う機能を有し、表示映像の特徴量に応じてバックライトの発光輝度を制御する液晶表示装置において、３Ｄ表示を行う際にバックライトの発光輝度が変化しても３Ｄ表示画面を確実に視認できるようにすることができる。 According to the present invention, in a liquid crystal display device having a function of performing 3D display by an active shutter method and controlling the light emission luminance of the backlight according to the feature amount of the display image, the light emission of the backlight when performing the 3D display. Even when the luminance changes, the 3D display screen can be reliably recognized.
本発明による液晶表示装置の構成例を示すブロック図である。It is a block diagram which shows the structural example of the liquid crystal display device by this invention. ３Ｄ表示のバックライトの点灯期間と３Ｄメガネのシャッターの開タイミングの状態を説明するための図である。It is a figure for demonstrating the lighting period of the backlight of 3D display, and the state of the opening timing of the shutter of 3D glasses. ３Ｄ表示のバックライトの点灯期間と３Ｄメガネのシャッターの開タイミングの状態を説明するための他の図である。It is another figure for demonstrating the lighting period of the backlight of 3D display, and the state of the opening timing of the shutter of 3D glasses. ３Ｄ表示のバックライトの点灯期間と３Ｄメガネのシャッターの開タイミングの状態を説明するためのさらに他の図である。FIG. 10 is still another diagram for explaining the state of the lighting period of the backlight of 3D display and the opening timing of the shutter of the 3D glasses. ３Ｄ表示のバックライトの点灯期間と３Ｄメガネのシャッターの開タイミングの状態を説明するためのさらに他の図である。FIG. 10 is still another diagram for explaining the state of the lighting period of the backlight of 3D display and the opening timing of the shutter of the 3D glasses. バックライトの点灯期間と３Ｄメガネのシャッターの開タイミングがずれるときの状態を説明するための図である。It is a figure for demonstrating a state when the lighting period of a backlight and the opening timing of the shutter of 3D glasses shift. バックライトの点灯期間と３Ｄメガネのシャッターの開タイミングがずれるときの状態を説明するための他の図である。It is another figure for demonstrating a state when the lighting period of a backlight and the opening timing of the shutter of 3D glasses shift.
　図１は、本発明による液晶表示装置の要部の構成例を示す図で、映像信号処理に係る機能ブロックを示す図である。
　チューナ部１は、アンテナを介して受信した放送信号を選局して復調し、入力信号切換部３に出力する。外部入力部２は、外部入力端子に入力したレコーダなどの外部機器からの信号、ＰＣ入力端子に入力したＰＣ（Personal Computer）機器からの映像信号、あるいは公衆ネットワークを介して入力した映像信号等が入力する。入力信号切換部３では、図示しない操作入力手段に対するユーザ操作等に応じて、チューナ部１から出力された映像信号あるいは外部入力部２から出力された映像信号を適宜切り換えて出力する。 FIG. 1 is a diagram illustrating a configuration example of a main part of a liquid crystal display device according to the present invention, and is a diagram illustrating functional blocks related to video signal processing.
The tuner unit 1 selects and demodulates the broadcast signal received via the antenna, and outputs it to the input signal switching unit 3. The external input unit 2 receives a signal from an external device such as a recorder input to the external input terminal, a video signal from a PC (Personal Computer) device input to the PC input terminal, a video signal input via a public network, or the like. input. The input signal switching unit 3 appropriately switches and outputs the video signal output from the tuner unit 1 or the video signal output from the external input unit 2 in accordance with a user operation or the like on an operation input unit (not shown).
　ＡＤ変換回路４，５は、入力信号がアナログ信号である場合に、ＡＤ変換を行ってデジタル信号に変換する。ＡＤ変換回路４は３次元ＹＣ分離を行うときに使用し、他方のＡＤ変換回路５は、３次元ＹＣ分離を行わないときに使用する。
　３次元（３Ｄ）ＹＣ分離回路６は、コンポジット信号からのＹＣ分離を行う。３次元ＹＣ分離は、現フレーム画像とその直前のフレーム画像との間の相関性を利用して、フレーム間で相関処理を行うことによって効率的かつ正確にＹＣ分離処理を行うものである。 When the input signal is an analog signal, the AD conversion circuits 4 and 5 perform AD conversion and convert it into a digital signal. The AD conversion circuit 4 is used when three-dimensional YC separation is performed, and the other AD conversion circuit 5 is used when three-dimensional YC separation is not performed.
A three-dimensional (3D) YC separation circuit 6 performs YC separation from the composite signal. In the three-dimensional YC separation, the correlation between the current frame image and the immediately preceding frame image is used to perform the correlation processing between frames, thereby efficiently and accurately performing the YC separation processing.
　３ＤＹＣ分離回路６から出力された映像信号、またはＡＤ変換回路５から出力された映像信号は、色空間変換回路７に入力される。
　また、ＨＤＭＩ入力部１６は、ＨＤＭＩ（High-Definition Multimedia Interface）インタフェースによって送信されたデジタル映像信号を入力し、色空間変換回路７に出力する。色空間変換回路７は、ＹＵＶビデオ信号をＲＧＢ信号に変換する色空間変換を行う。 The video signal output from the 3DYC separation circuit 6 or the video signal output from the AD conversion circuit 5 is input to the color space conversion circuit 7.
Also, the HDMI input unit 16 inputs a digital video signal transmitted through a high-definition multimedia interface (HDMI) interface and outputs the digital video signal to the color space conversion circuit 7. The color space conversion circuit 7 performs color space conversion for converting a YUV video signal into an RGB signal.
　色空間変換された映像信号は、ガンマ補正回路８で所定のガンマ補正が行われ、パネル制御部９に出力される。パネル制御部９は、映像信号を液晶パネル１０に表示可能な信号として出力し、液晶パネル１０の表示を制御する。入力映像信号が３Ｄ映像である場合、液晶パネル１０に入力される映像信号は、右目用の映像と左目用の映像とがフレーム毎に交互に表示されるものである。 The video signal subjected to the color space conversion is subjected to predetermined gamma correction by the gamma correction circuit 8 and output to the panel control unit 9. The panel control unit 9 outputs a video signal as a signal that can be displayed on the liquid crystal panel 10 and controls the display of the liquid crystal panel 10. When the input video signal is a 3D video, the video signal input to the liquid crystal panel 10 is such that a right-eye video and a left-eye video are alternately displayed for each frame.
　２Ｄ／３Ｄ判定回路部１１は、本発明の２Ｄ／３Ｄ判定部に該当するもので、入力映像信号のフォーマットを確認し、入力映像信号が２Ｄ映像か３Ｄ映像かを判定する。判定結果は、システム制御部１２出力される。システム制御部１２は、バックライト１４の点灯制御を行うバックライト制御部１３と、外部接続される３Ｄメガネのシャッター開閉制御を行うメガネ制御部１５とを制御する。本発明の制御部は、システム制御部１２，バックライト制御部１３、及びメガネ制御部１５によって実現される。 The 2D / 3D determination circuit unit 11 corresponds to the 2D / 3D determination unit of the present invention, confirms the format of the input video signal, and determines whether the input video signal is 2D video or 3D video. The determination result is output to the system control unit 12. The system control unit 12 controls a backlight control unit 13 that performs lighting control of the backlight 14 and a glasses control unit 15 that performs shutter opening / closing control of externally connected 3D glasses. The control unit of the present invention is realized by the system control unit 12, the backlight control unit 13, and the glasses control unit 15.
　バックライト１４は、液晶パネル１０を照明することで液晶パネル１０に表示した画像を変調して表示させる。バックライト１４は、例えば複数のＬＥＤ（Light Emitting Diode）をマトリックス状に配列したものが用いられる。 The backlight 14 illuminates the liquid crystal panel 10 to modulate and display the image displayed on the liquid crystal panel 10. As the backlight 14, for example, a plurality of LEDs (LightmEmitting Diode) arranged in a matrix is used.
　２Ｄ／３Ｄ判定回路部１１により、入力映像信号が３Ｄ映像と判定された場合、システム制御部１２は、メガネ制御部１５を制御し、３Ｄメガネのシャッター開閉を制御する制御信号を送信させる。３Ｄメガネは、左目用と右目用のシャッターを備え、メガネ制御部１５から送信された制御信号に従って左目用のシャッターと右目用のシャッターの開閉を制御する。この開閉制御は、ＰＷＭ制御によって行われる。
　この制御信号により、３Ｄメガネでは、液晶パネル１０に表示させる右目用の映像と左目用の映像に合わせて、左目用のシャッターと右目用のシャッターとをそれぞれ開閉制御し、３Ｄ映像をユーザが視認できるようにしている。左目用のシャッターと右目用のシャッターは、例えば液晶の動作によりシャッター機能をＯＮ／ＯＦＦする液晶シャッターにより構成される。 When the 2D / 3D determination circuit unit 11 determines that the input video signal is a 3D video, the system control unit 12 controls the glasses control unit 15 to transmit a control signal for controlling the shutter opening / closing of the 3D glasses. The 3D glasses include left-eye and right-eye shutters, and control the opening and closing of the left-eye shutter and the right-eye shutter according to a control signal transmitted from the glasses control unit 15. This opening / closing control is performed by PWM control.
With this control signal, the 3D glasses control the opening and closing of the left-eye shutter and the right-eye shutter in accordance with the right-eye video and the left-eye video displayed on the liquid crystal panel 10 so that the user can visually recognize the 3D video. I can do it. The shutter for the left eye and the shutter for the right eye are constituted by, for example, a liquid crystal shutter that turns on / off the shutter function by the operation of liquid crystal.
　システム制御部１２は、映像信号の特徴量に応じてバックライト１４の発光輝度を制御する機能であるアクティブバックライトの機能を有する。アクティブバックライトでは、上述したように、映像の所定の特徴を表す特徴量とバックライトの発光輝度との関係を規定する輝度制御特性を予め定めておき、映像信号のフレームごとに上記特徴量を取得し、その特徴量に応じてバックライト１４の発光輝度を制御する。特徴量としては、例えば映像の平均輝度を示すＡＰＬ（Average Picture Level）や、映像信号のピーク値などが用いられる。また、輝度制御特性は、適宜定められることができるが、特徴量が小さくなるほどバックライトの発光輝度を低下させるような輝度制御特性が定められる。これにより、特徴量の小さい暗い映像ほどバックライトの発光輝度を低下させることで、映像の黒浮きを抑えて映像品位を高くするなどの制御を行う。 The system control unit 12 has an active backlight function that is a function of controlling the light emission luminance of the backlight 14 according to the feature amount of the video signal. In the active backlight, as described above, a luminance control characteristic that defines the relationship between the feature amount representing a predetermined feature of the video and the light emission luminance of the backlight is determined in advance, and the feature amount is set for each frame of the video signal. The light emission brightness of the backlight 14 is controlled in accordance with the acquired feature amount. As the feature amount, for example, APL (Average Picture Level) indicating the average luminance of the video, the peak value of the video signal, or the like is used. The luminance control characteristic can be determined as appropriate. However, the luminance control characteristic is set such that the emission luminance of the backlight decreases as the feature amount decreases. As a result, the darker video having a smaller feature amount reduces the backlight emission luminance, thereby performing control such as suppressing black floating of the video and improving the video quality.
　システム制御部１２は、映像信号から上記の特徴量を取得し、所定の輝度制御特性に従ってバックライト１４の発光輝度を定める調光信号をバックライト制御部１３に出力する。バックライト制御部１３では、入力された調光信号に従ってバックライト１４の発光輝度を制御する。ここで、バックライト１４は、ＰＷＭ制御と電圧制御との両方のバックライトの点灯制御機能を有し、２Ｄ／３Ｄに応じてこれらの点灯制御方法を切り替える。　 The system control unit 12 acquires the above-described feature amount from the video signal, and outputs a dimming signal that determines the light emission luminance of the backlight 14 to the backlight control unit 13 according to a predetermined luminance control characteristic. The backlight control unit 13 controls the light emission luminance of the backlight 14 according to the input dimming signal. Here, the backlight 14 has the lighting control function of both the PWM control and the voltage control, and switches these lighting control methods according to 2D / 3D. *
　すなわち、本発明に係る実施形態では、２Ｄ／３Ｄ判定回路部１１にて入力映像信号のフォーマットが２Ｄであると判定した場合と、３Ｄであると判定した場合とでバックライト１４の点灯制御を変更する。
　具体的には、２Ｄ／３Ｄ判定回路部１１が入力映像信号を２Ｄ映像であると判定した場合、システム制御部１２は、バックライト制御部１３に対してＰＷＭによりバックライト１４の点灯制御を行うように命令する。 That is, in the embodiment according to the present invention, the lighting control of the backlight 14 is controlled depending on whether the 2D / 3D determination circuit unit 11 determines that the format of the input video signal is 2D or 3D. change.
Specifically, when the 2D / 3D determination circuit unit 11 determines that the input video signal is a 2D video, the system control unit 12 controls the backlight control unit 13 to turn on the backlight 14 by PWM. To order.
　一方、２Ｄ／３Ｄ判定回路部１１が入力映像信号を３Ｄ映像であると判定した場合、システム制御部１２は、バックライト制御部１３に対して電圧制御によりバックライト１４の点灯制御を行うように命令する。電圧制御によって点灯制御を行うことにより、バックライト１４は、調光設定に応じて一定レベルで点灯されるため、３Ｄ映像を表示するときにアクティブバックライトが動作してバックライトの発光輝度が低下したとしても、バックライトの点灯期間と３Ｄメガネのシャッターの開放期間がずれて映像が視認できなくなる、という問題を解消することができる。 On the other hand, when the 2D / 3D determination circuit unit 11 determines that the input video signal is a 3D video, the system control unit 12 controls the backlight control unit 13 to turn on the backlight 14 by voltage control. Command. By performing lighting control by voltage control, the backlight 14 is lit at a constant level according to the dimming setting, so that the active backlight operates when displaying 3D video, and the light emission luminance of the backlight decreases. Even so, it is possible to solve the problem that the lighting period of the backlight and the opening period of the shutter of the 3D glasses are shifted to make the video invisible.
　ＰＷＭにより２Ｄ映像の表示時の調光制御を行う場合、バックライト制御部１３は、システム制御部１２からの調光信号を受けとり、ＰＷＭ変調によりバックライト１４の発光輝度を制御する。ここでは、バックライト１４のＬＥＤへの印加電圧は一定にして、スイッチ素子のＯＮ／ＯＦＦのデューティ比を変化させることにより調光を行なう。ＬＥＤの駆動にＰＷＭ変調を用いることにより、ＬＥＤに流れる電流のピーク値を変化させることなく、ＬＥＤに流れる電流量を変化させている。ＬＥＤの明るさは、ＬＥＤに流れる電流量により決まり、調光ＰＷＭ信号のデューティ比が大きいほどバックライト１４の発光輝度を高くすることができる。 When performing dimming control when displaying 2D video by PWM, the backlight control unit 13 receives a dimming signal from the system control unit 12 and controls the light emission luminance of the backlight 14 by PWM modulation. Here, dimming is performed by changing the ON / OFF duty ratio of the switch element while keeping the voltage applied to the LED of the backlight 14 constant. By using PWM modulation for driving the LED, the amount of current flowing through the LED is changed without changing the peak value of the current flowing through the LED. The brightness of the LED is determined by the amount of current flowing through the LED, and the larger the duty ratio of the dimming PWM signal, the higher the emission luminance of the backlight 14.
　一方、電圧制御により３Ｄ映像の表示時の調光制御を行う場合、バックライト１４のＬＥＤに印加する電圧を増減し、ＬＥＤに流れる電流ピーク値を変化させることでその明るさを変化させる。ここでは、ＬＥＤの明るさ（ＬＥＤに流す電流量）を制御するための電圧を一定にして、その電圧に応じた発光輝度でバックライト１４を発光させる。このような定電圧制御の電圧を上げれば、バックライト１４を明るくすることができる。 On the other hand, when dimming control is performed during the display of 3D video by voltage control, the voltage applied to the LED of the backlight 14 is increased or decreased, and the brightness is changed by changing the peak value of the current flowing through the LED. Here, the voltage for controlling the brightness of the LED (the amount of current flowing through the LED) is made constant, and the backlight 14 is caused to emit light with the light emission luminance corresponding to the voltage. If the voltage for such constant voltage control is increased, the backlight 14 can be brightened.
　図２～図３は、３Ｄ表示のバックライトの点灯期間と３Ｄメガネのシャッターの開タイミングの状態を説明するための図である。
　ここでは、液晶応答特性がそれほど高速ではないノーマルパネルを用いて３Ｄ表示を行う場合等において、クロストークを避けるために３Ｄメガネのシャッターを１フレーム期間内の所定期間だけ開けるように制御するものとする。 2 to 3 are diagrams for explaining the state of the lighting period of the 3D display backlight and the opening timing of the shutter of the 3D glasses.
Here, in the case where 3D display is performed using a normal panel whose liquid crystal response characteristics are not so high, control is performed so that the shutter of the 3D glasses is opened only for a predetermined period within one frame period in order to avoid crosstalk. To do.
　図２の例は、映像信号として２５５階調の白（８ビット表現）が表示されているものとする。つまり、映像信号の最大階調値が表示され、映像特徴量は、ＡＰＬであってもピーク値であっても最大値になる。この場合、アクティブバックライトの作用により、バックライトは輝度制御特性における最大の発光輝度で発光される。 In the example of FIG. 2, it is assumed that 255 gradation white (8-bit representation) is displayed as a video signal. That is, the maximum gradation value of the video signal is displayed, and the video feature amount becomes the maximum value regardless of whether it is APL or peak value. In this case, due to the action of the active backlight, the backlight emits light with the maximum light emission luminance in the luminance control characteristics.
　図２では、電圧制御によるバックライトの点灯輝度レベル（ＢＬ）と、３Ｄメガネの開口率の時間変化（メガネ）と、メガネを通しての映像の輝度レベルの時間変化（ＢＬ＋メガネ）とが示されている。メガネの開口率は０％で全く光を通さず、１００％で光をすべて通す。図２においては開口率は０％から徐々に上がり、１００％になった後、急激に０％に落とす特性としている。メガネを通しての映像の輝度レベルについてはバックライトの輝度とメガネの開口率によって合成された映像輝度となる。３Ｄ視聴時、ユーザは、この映像輝度を見ることになる。
　上記のように、２Ｄ／３Ｄ判定回路部１１で入力映像信号が３Ｄ映像であると判定されると、システム制御部１２の制御に従って、バックライト制御部１３では、電圧制御によるバックライト１４の調光制御を行う。 In FIG. 2, the lighting brightness level (BL) of the backlight by voltage control, the temporal change of the aperture ratio of the 3D glasses (glasses), and the temporal change of the luminance level of the video through the glasses (BL + glasses) are shown. Yes. The aperture ratio of the glasses is 0%, which does not transmit light at all, and 100% transmits all light. In FIG. 2, the aperture ratio gradually increases from 0%, reaches 100%, and then drops rapidly to 0%. The luminance level of the image through the glasses is an image luminance synthesized by the luminance of the backlight and the aperture ratio of the glasses. When viewing 3D, the user sees this video luminance.
As described above, when the 2D / 3D determination circuit unit 11 determines that the input video signal is 3D video, the backlight control unit 13 adjusts the backlight 14 by voltage control according to the control of the system control unit 12. Perform light control.
　ここでは、高階調の映像信号が表示されるため、アクティブバックライトの作用により比較的高い電圧でバックライトの発光部分が制御されるが、一定電圧でバックライト１４が発光制御されるため、そのフレーム期間内では、一定のレベルでバックライト１４が発光し続ける。 Here, since the video signal of high gradation is displayed, the light emission part of the backlight is controlled with a relatively high voltage by the action of the active backlight, but the backlight 14 is controlled to emit light with a constant voltage. Within the frame period, the backlight 14 continues to emit light at a constant level.
　一方、３Ｄメガネは、映像の１フレーム内で一定期間だけシャッターを開放するが、バックライト１４は一定レベルで点灯しているため、３Ｄメガネのシャッターが開となっているときにバックライト１４が消灯することはなく、バックライト１４の点灯期間とシャッターの開放期間とが常に重複するため、ユーザはメガネ越しに確実に３Ｄ映像を視認することができる。 On the other hand, the 3D glasses open the shutter for a certain period within one frame of the image, but the backlight 14 is lit at a certain level, so the backlight 14 is turned on when the shutter of the 3D glasses is open. Since the backlight 14 does not turn off and the lighting period of the backlight 14 and the shutter opening period always overlap, the user can surely view the 3D image through the glasses.
　また、図３の例は、映像信号が１階調の白（８ビット表現）が表示されているものとする。つまり、映像はほぼ黒であり、映像特徴量は、ＡＰＬであってもピーク値であってもほぼ最低値になる。この場合、アクティブバックライトの作用により、バックライトは輝度制御特性におけるほぼ最少の発光輝度で発光される。このときバックライト１４は、アクティブバックライトの作用により低い電圧でバックライトの発光部分が制御される。 Further, in the example of FIG. 3, it is assumed that the video signal displays one gradation white (8-bit expression). That is, the video is almost black, and the video feature amount is almost the lowest value whether it is APL or the peak value. In this case, due to the action of the active backlight, the backlight emits light with almost the minimum light emission luminance in the luminance control characteristics. At this time, the backlight 14 controls the light emission portion of the backlight at a low voltage by the action of the active backlight.
　しかしながら、この場合にもバックライトの発光輝度は低減するが、３Ｄメガネのシャッターが開となっているときにバックライトが消灯することはなく、バックライト１４の点灯期間とシャッターの開放期間とが常に重複するため、ユーザはメガネ越しに確実に３Ｄ映像を視認することができる。 However, in this case as well, the light emission luminance of the backlight is reduced, but the backlight is not turned off when the shutter of the 3D glasses is open, and the lighting period of the backlight 14 and the opening period of the shutter are Since they always overlap, the user can surely view the 3D image through the glasses.
　上記のように、本発明に係る液晶表示装置によれば、表示すべき映像信号が２Ｄ映像か３Ｄ映像の信号かを検出し、２Ｄ映像を表示するときにはバックライト１４の点灯制御をパルス幅変調（ＰＷＭ）によって実施し、３Ｄ映像を表示するときにはバックライト１４の点灯制御を電圧制御に切換える。これにより、入力信号の特徴量に応じてアクティブバックライトが動作し、バックライトの発光輝度が低下したとしても、３Ｄメガネのシャッターの開放タイミングとバックライトの点灯タイミングとが一致しなくなることがなく、３Ｄメガネ越しの輝度が極端に悪化して映像が視認できなるという問題を解消することができる。 As described above, according to the liquid crystal display device of the present invention, it is detected whether the video signal to be displayed is a 2D video signal or a 3D video signal, and when the 2D video is displayed, the lighting control of the backlight 14 is pulse width modulated. (PWM) The lighting control of the backlight 14 is switched to voltage control when displaying a 3D video. As a result, even when the active backlight operates in accordance with the feature amount of the input signal and the light emission luminance of the backlight decreases, the shutter opening timing of the 3D glasses and the lighting timing of the backlight do not become inconsistent. The problem that the luminance through the 3D glasses is extremely deteriorated and the video can be visually recognized can be solved.
　図４～図５は、３Ｄ表示のときのバックライト制御の他の例を説明する図で、３Ｄ表示のバックライトの点灯期間と３Ｄメガネのシャッターの開タイミングの状態を示すものである。
　上記図２～図３で説明した例では、３Ｄ映像を表示するときにはバックライト１４の点灯制御をＰＷＭ制御から電圧制御に切換えて、バックライトの発光輝度が一定レベルになるように制御した。これに対して、本例では、３Ｄ映像を表示する場合には、バックライト１４の発光輝度をＰＷＭと電圧制御を併用して制御し、点灯のデューティ比を変化させることなく、発光輝度レベルを電圧制御により変化させる。 4 to 5 are diagrams for explaining other examples of backlight control during 3D display, and show the lighting period of the backlight for 3D display and the opening timing of the shutter of the 3D glasses.
In the example described with reference to FIGS. 2 to 3, when the 3D image is displayed, the lighting control of the backlight 14 is switched from the PWM control to the voltage control so that the light emission luminance of the backlight becomes a constant level. On the other hand, in this example, when displaying a 3D image, the light emission luminance of the backlight 14 is controlled by using both PWM and voltage control, and the light emission luminance level is changed without changing the lighting duty ratio. Change by voltage control.
　ここでは、上記の例と同様に、液晶応答特性がそれほど高速ではないノーマルパネルを用いて３Ｄ表示を行う場合等において、クロストークを避けるために３Ｄメガネのシャッターを１フレーム期間内の所定期間だけ開けるように制御するものとする。 Here, as in the above example, when performing 3D display using a normal panel whose liquid crystal response characteristics are not so fast, the shutter of the 3D glasses is set to a predetermined period within one frame period in order to avoid crosstalk. It shall be controlled to open.
　図４の例は、映像信号として２５５階調の白（８ビット表現）が表示されているものとする。つまり、映像信号の最大階調値が表示され、映像特徴量は、ＡＰＬであってもピーク値であっても最大値になる。この場合、アクティブバックライトの作用により、バックライトは輝度制御特性における最大の発光輝度で発光される。 In the example of FIG. 4, it is assumed that 255 gradation white (8-bit expression) is displayed as a video signal. That is, the maximum gradation value of the video signal is displayed, and the video feature amount becomes the maximum value regardless of whether it is APL or peak value. In this case, due to the action of the active backlight, the backlight emits light with the maximum light emission luminance in the luminance control characteristics.
　図４では、ＰＷＭ制御によるバックライトの点灯輝度レベル（ＢＬ）と、３Ｄメガネの開口率の時間変化（メガネ）と、メガネを通しての映像の輝度レベルの時間変化（ＢＬ＋メガネ）とが示されている。この場合、３Ｄメガネの開口率は０％から徐々に上がり、１００％になった後、急激に０％に落とす特性としている。
　一方、バックライトは、ＰＷＭ制御と電圧制御とが併用される。２Ｄ／３Ｄ判定回路部１１で入力映像信号が３Ｄ映像であると判定されると、システム制御部１２の制御に従って、バックライト制御部１３では、ＰＷＭ制御と電圧制御との併用によりバックライト１４の調光制御を行う。 In FIG. 4, the lighting brightness level (BL) of the backlight by PWM control, the temporal change in the aperture ratio of the 3D glasses (glasses), and the temporal change in the luminance level of the video through the glasses (BL + glasses) are shown. Yes. In this case, the aperture ratio of the 3D glasses gradually increases from 0%, reaches 100%, and then drops rapidly to 0%.
On the other hand, the backlight uses both PWM control and voltage control. When the 2D / 3D determination circuit unit 11 determines that the input video signal is 3D video, the backlight control unit 13 uses the PWM control and the voltage control in combination with the backlight 14 in accordance with the control of the system control unit 12. Dimming control is performed.
　ここでは、高階調の映像信号が表示されているため、アクティブバックライトの作用により比較的高い発光輝度でバックライトを発光させる。このときに、ＰＷＭ制御により特定のデューティ比でバックライトの発光が制御される。そして、一定の電圧でバックライトのＬＥＤを発光させる。ＬＥＤの明るさは、ＬＥＤに流れる電流量により決まるが、ＬＥＤに印加する電圧を制御することによるＬＥＤの電流のピーク値と、ＰＷＭ制御によるデューティ比との併用により、所望のバックライトの発光輝度が得られるように制御する。 Here, since a high gradation video signal is displayed, the backlight is caused to emit light with a relatively high light emission luminance by the action of the active backlight. At this time, the light emission of the backlight is controlled at a specific duty ratio by PWM control. Then, the backlight LED is caused to emit light at a constant voltage. The brightness of the LED is determined by the amount of current flowing through the LED, but the desired luminance of the backlight is obtained by combining the peak value of the LED current by controlling the voltage applied to the LED and the duty ratio by PWM control. Control to obtain
　３Ｄメガネは、映像の１フレーム内で一定期間だけシャッターを開放する。バックライトが点灯しているときに（ＢＬ：Ｈｉ）、３Ｄメガネのシャッターが開となっていれば、ユーザはそのバックライトの点灯期間とシャッターの開放期間とが重複する間、映像を視認することができる。この例の場合、ＢＬ＋メガネでは、バックライトの点灯期間（ＢＬ：Ｈｉ）と、シャッターの開放期間（メガネ：Ｈｉ）の重複部分があるため、ユーザはその重複部分で映像を視認することができる。 3D glasses open the shutter only for a certain period within one frame of video. If the backlight of the 3D glasses is open when the backlight is lit (BL: Hi), the user views the image while the backlight lighting period and the shutter opening period overlap. be able to. In this example, in the BL + glasses, since there is an overlapping part of the backlight lighting period (BL: Hi) and the shutter opening period (glasses: Hi), the user can visually recognize the image at the overlapping part. .
　上記の場合、所望の発光輝度を得るためにデューティ比を大きくして、電圧を下げるようにすれば、バックライトの点灯期間が長くなり、メガネのシャッターの開放期間との重複部分をさらに長くとりやすくなる。しかしこの場合には、シャッターが開いているときの画面輝度が相対的にやや暗くなる。従って、両者の兼ね合いにより最適なデューティ比と電圧値とを定めるようにする。 In the above case, if the duty ratio is increased and the voltage is lowered to obtain the desired light emission luminance, the backlight lighting period becomes longer, and the overlapping part with the shutter opening period of the glasses is further increased. It becomes easy. However, in this case, the screen brightness when the shutter is open is relatively dark. Therefore, the optimum duty ratio and voltage value are determined by the balance between the two.
　また、図５の例は、映像信号が１階調の白（８ビット表現）が表示されているものとする。つまり、映像はほぼ黒であり、映像特徴量は、ＡＰＬであってもピーク値であってもほぼ最低値になる。この場合、アクティブバックライトの作用により、バックライトは輝度制御特性におけるほぼ最少の発光輝度で発光される。 Further, in the example of FIG. 5, it is assumed that the video signal is displayed with one gradation of white (8-bit expression). That is, the video is almost black, and the video feature amount is almost the lowest value whether it is APL or the peak value. In this case, due to the action of the active backlight, the backlight emits light with almost the minimum light emission luminance in the luminance control characteristics.
　このときバックライト１４は、ＰＷＭ制御と電圧制御とよって制御されるが、ＰＷＭ制御によるディーティ比は維持したまま、電圧を下げてバックライトの発光輝度を制御する。これにより、電圧低下によってＬＥＤへの電流ピーク値が低下してバックライトの発光輝度は低下するが、デューティ比は変化しないため、バックライト１４の点灯期間とシャッターの開放期間との重複が維持され、バックライトの発光輝度が低下してもユーザはメガネ越しに確実に３Ｄ映像を視認することができる。 At this time, although the backlight 14 is controlled by PWM control and voltage control, the voltage is lowered to control the light emission luminance of the backlight while maintaining the duty ratio by the PWM control. As a result, the current peak value to the LED decreases due to the voltage drop and the light emission luminance of the backlight decreases, but the duty ratio does not change, so the overlap between the lighting period of the backlight 14 and the shutter opening period is maintained. Even if the light emission luminance of the backlight decreases, the user can surely view the 3D image through the glasses.
　なお、上記の例ではデューティ比を常に一定に維持したままＬＥＤに印加する電圧を変化させるようにしているが、デューティ比は常に一定でなくてもよい。例えば、バックライトの発光輝度を低下させるときには、デューティ比を若干低下させつつ、同時に電圧も低下させることで、シャッターの開放期間との重複を維持しながら、電圧の低下による輝度の低下を抑えるようにしてもよい。これらＰＷＭ制御のデューティ比と、電圧制御の電圧値は、メガネのシャッターの開閉制御のタイミングに合わせて最適な条件を選択することができる。 In the above example, the voltage applied to the LED is changed while the duty ratio is always kept constant, but the duty ratio may not always be constant. For example, when lowering the light emission brightness of the backlight, the duty ratio is slightly reduced and the voltage is also reduced at the same time, so that the reduction in brightness due to the voltage drop is suppressed while maintaining the overlap with the shutter opening period. It may be. As for the duty ratio of the PWM control and the voltage value of the voltage control, optimum conditions can be selected according to the timing of opening / closing control of the shutter of the glasses.
　上記のように、本発明に係る液晶表示装置によれば、表示すべき映像信号が２Ｄ映像か３Ｄ映像の信号かを検出し、２Ｄ映像を表示するときにはバックライト１４の点灯制御をパルス幅変調（ＰＷＭ）によって実施し、３Ｄ映像を表示するときにはバックライト１４の点灯制御をＰＷＭ制御と電圧制御との併用に切換える。これにより、入力信号の特徴量に応じてアクティブバックライトが動作し、バックライトの発光輝度が低下したとしても、３Ｄメガネのシャッターの開放タイミングとバックライトの点灯タイミングとが一致しなくなることがなく、３Ｄメガネ越しの輝度が極端に悪化して映像が視認できなるという問題を解消することができる。 As described above, according to the liquid crystal display device of the present invention, it is detected whether the video signal to be displayed is a 2D video signal or a 3D video signal, and when the 2D video is displayed, the lighting control of the backlight 14 is pulse width modulated. When the 3D video is displayed, the lighting control of the backlight 14 is switched to the combined use of the PWM control and the voltage control. As a result, even when the active backlight operates in accordance with the feature amount of the input signal and the light emission luminance of the backlight decreases, the shutter opening timing of the 3D glasses and the lighting timing of the backlight do not become inconsistent. The problem that the luminance through the 3D glasses is extremely deteriorated and the video can be visually recognized can be solved.
１…チューナ部、２…外部入力部、３…入力信号切換部、４，５…ＡＤ変換回路、６…３ＤＹＣ分離回路、７…色空間変換回路、８…ガンマ補正回路、９…パネル制御部、１０…液晶パネル、１１…２Ｄ／３Ｄ判定回路部、１２…システム制御部、１３…バックライト制御部、１４…バックライト、１５…メガネ制御部、１６…ＨＤＭＩ入力部。 DESCRIPTION OF SYMBOLS 1 ... Tuner part, 2 ... External input part, 3 ... Input signal switching part, 4, 5 ... AD conversion circuit, 6 ... 3DYC separation circuit, 7 ... Color space conversion circuit, 8 ... Gamma correction circuit, 9 ... Panel control part DESCRIPTION OF SYMBOLS 10 ... Liquid crystal panel, 11 ... 2D / 3D determination circuit part, 12 ... System control part, 13 ... Backlight control part, 14 ... Backlight, 15 ... Glasses control part, 16 ... HDMI input part.

Claims (3)

  1. 　液晶パネルと、該液晶パネルを照明するバックライトと、前記液晶パネルの表示及び前記バックライトの点灯を制御する制御部とを備えた液晶表示装置において、
    　前記液晶パネルに表示させる映像が２Ｄ映像か３Ｄ映像かを判定する２Ｄ／３Ｄ判定部を備え、
    　前記制御部は、前記２Ｄ／３Ｄ判定部によって２Ｄ映像であることが判定された場合、前記バックライトの点灯制御を、パルス幅変調制御によって実行し、前記２Ｄ／３Ｄ判定部によって３Ｄ映像であることが判定された場合、前記バックライトの点灯制御を電圧制御によって実行することを特徴とする液晶表示装置。     In a liquid crystal display device comprising: a liquid crystal panel; a backlight that illuminates the liquid crystal panel; and a control unit that controls display of the liquid crystal panel and lighting of the backlight.
    A 2D / 3D determination unit for determining whether a video to be displayed on the liquid crystal panel is a 2D video or a 3D video;
    When the 2D / 3D determination unit determines that the 2D video is the 2D video, the control unit performs the backlight lighting control by pulse width modulation control, and the 2D / 3D determination unit generates the 3D video. If it is determined, the liquid crystal display device is characterized in that the lighting control of the backlight is executed by voltage control.
  2. 　液晶パネルと、該液晶パネルを照明するバックライトと、前記液晶パネルの表示及び前記バックライトの点灯を制御する制御部とを備えた液晶表示装置において、
    　前記液晶パネルに表示させる映像が２Ｄ映像か３Ｄ映像かを判定する２Ｄ／３Ｄ判定部を備え、
    　前記制御部は、前記２Ｄ／３Ｄ判定部によって２Ｄ映像であることが判定された場合、前記バックライトの点灯制御を、パルス幅変調制御によって実行し、前記２Ｄ／３Ｄ判定部によって３Ｄ映像であることが判定された場合、前記バックライトの点灯制御を電圧制御とパルス幅変調制御を併用することによって実行することを特徴とする液晶表示装置。     In a liquid crystal display device comprising: a liquid crystal panel; a backlight that illuminates the liquid crystal panel; and a control unit that controls display of the liquid crystal panel and lighting of the backlight.
    A 2D / 3D determination unit for determining whether a video to be displayed on the liquid crystal panel is a 2D video or a 3D video;
    When the 2D / 3D determination unit determines that the 2D video is the 2D video, the control unit performs the backlight lighting control by pulse width modulation control, and the 2D / 3D determination unit generates the 3D video. When it is determined, the liquid crystal display device is characterized in that the lighting control of the backlight is executed by using both voltage control and pulse width modulation control.
  3. 　請求項１または２に記載の液晶表示装置において、
    　前記液晶パネルを視認するための左右のシャッターを備える３Ｄメガネと、前記３Ｄメガネに制御信号を送信する送信部とを有し、
    　前記制御部は、右目用の画像と左目用の画像を交互に表示するとともに、前記３Ｄメガネの前記シャッターを開閉する制御信号を生成して前記送信部から送信させ、
    　前記制御部は、前記３Ｄ映像を前記液晶パネルに表示させる際に、前記３Ｄメガネの前記シャッターをパルス幅変調制御によって開閉させる前記制御信号を生成することを特徴とする液晶表示装置。     The liquid crystal display device according to claim 1 or 2,
    3D glasses having left and right shutters for visually recognizing the liquid crystal panel, and a transmitter for transmitting a control signal to the 3D glasses,
    The control unit alternately displays an image for the right eye and an image for the left eye, generates a control signal for opening and closing the shutter of the 3D glasses, and transmits the control signal from the transmission unit.
    The said control part produces | generates the said control signal which opens and closes the said shutter of the said 3D glasses by pulse width modulation control, when displaying the said 3D image | video on the said liquid crystal panel.
PCT/JP2012/073047 2012-02-24 2012-09-10 Liquid-crystal display device WO2013125077A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2012038203A JP5326016B2 (en) 2012-02-24 2012-02-24 Liquid crystal display
JP2012-038203 2012-02-24

Publications (1)

Publication Number Publication Date
WO2013125077A1 true WO2013125077A1 (en) 2013-08-29

Family

ID=49005281

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2012/073047 WO2013125077A1 (en) 2012-02-24 2012-09-10 Liquid-crystal display device

Country Status (2)

Country Link
JP (1) JP5326016B2 (en)
WO (1) WO2013125077A1 (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2015100806A1 (en) * 2013-12-30 2015-07-09 深圳市华星光电技术有限公司 Three-dimensional liquid crystal display device, shutter glasses, and shutter glasses control method
CN105489155A (en) * 2015-12-30 2016-04-13 广东威创视讯科技股份有限公司 Master control board of display unit of joint wall, display system of joint wall, and window opening method
US9513507B2 (en) 2013-12-30 2016-12-06 Shenzhen China Star Optoelectronics Technology Co., Ltd. Three-dimensional liquid crystal display device, and shutter glass and control method for the same
US11170723B2 (en) 2018-03-09 2021-11-09 MAX-PLANCK-Gesellschaft zur Förderung der Wissenschaften e.V. System for displaying information to a user

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR3011091A1 (en) * 2013-09-26 2015-03-27 Valeo Vision DATA DISPLAY LENSES HAVING AN ANTI-GLARE SCREEN
CN113920949A (en) * 2021-10-12 2022-01-11 西安热工研究院有限公司 2D (two-dimensional) regional dimming system and method for LCD (liquid crystal display) spliced screen

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2011135550A (en) * 2009-12-24 2011-07-07 Samsung Electronics Co Ltd Stereoscopic video display device and method of driving the same
JP2011150144A (en) * 2010-01-21 2011-08-04 Toshiba Corp Video display apparatus and video display method
JP2011188165A (en) * 2010-03-08 2011-09-22 Sharp Corp Video display device
JP2011191347A (en) * 2010-03-12 2011-09-29 Hitachi Consumer Electronics Co Ltd Display device and audiovisual device
WO2011148663A1 (en) * 2010-05-28 2011-12-01 シャープ株式会社 Liquid crystal display device and television receiver
WO2011148684A1 (en) * 2010-05-28 2011-12-01 シャープ株式会社 Liquid crystal display device

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2011135550A (en) * 2009-12-24 2011-07-07 Samsung Electronics Co Ltd Stereoscopic video display device and method of driving the same
JP2011150144A (en) * 2010-01-21 2011-08-04 Toshiba Corp Video display apparatus and video display method
JP2011188165A (en) * 2010-03-08 2011-09-22 Sharp Corp Video display device
JP2011191347A (en) * 2010-03-12 2011-09-29 Hitachi Consumer Electronics Co Ltd Display device and audiovisual device
WO2011148663A1 (en) * 2010-05-28 2011-12-01 シャープ株式会社 Liquid crystal display device and television receiver
WO2011148684A1 (en) * 2010-05-28 2011-12-01 シャープ株式会社 Liquid crystal display device

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2015100806A1 (en) * 2013-12-30 2015-07-09 深圳市华星光电技术有限公司 Three-dimensional liquid crystal display device, shutter glasses, and shutter glasses control method
US9513507B2 (en) 2013-12-30 2016-12-06 Shenzhen China Star Optoelectronics Technology Co., Ltd. Three-dimensional liquid crystal display device, and shutter glass and control method for the same
CN105489155A (en) * 2015-12-30 2016-04-13 广东威创视讯科技股份有限公司 Master control board of display unit of joint wall, display system of joint wall, and window opening method
CN105489155B (en) * 2015-12-30 2019-09-17 广东威创视讯科技股份有限公司 Master control borad, splicing wall display system and its windowing method of joined screen display unit
US11170723B2 (en) 2018-03-09 2021-11-09 MAX-PLANCK-Gesellschaft zur Förderung der Wissenschaften e.V. System for displaying information to a user
US11694640B2 (en) 2018-03-09 2023-07-04 MAX-PLANCK-Gesellschaft zur Förderung der Wissenschaften e.V. System for displaying information to a user

Also Published As

Publication number Publication date
JP2013175853A (en) 2013-09-05
JP5326016B2 (en) 2013-10-30

Similar Documents

Publication Publication Date Title
EP2043079A2 (en) Video displaying apparatus with dynamic brightness control of the backlight
US9191655B2 (en) Image processing apparatus, image display apparatus and image display system
JP5326016B2 (en) Liquid crystal display
US20110090321A1 (en) Display device, display method and computer program
JP2011069963A (en) Image display apparatus, image display observation system, and image display method
US8482605B2 (en) Image processing device, image display device, and image processing and display method and program
US20090122087A1 (en) Display device
US8436894B2 (en) Liquid crystal display system which adjusts backlight to generate a three-dimensional image effect and method thereof
JP5619863B2 (en) Non-glasses stereoscopic image display apparatus and control method thereof
GB2480363A (en) Stereoscopic image display with reduced ghosting
TWI415447B (en) Liquid crystal display system for displaying three-dimensional video and method of operating a liquid crystal display system
TWI419549B (en) Shutter glasses and method for controlling shutter glasses
WO2015033502A1 (en) Display device
US20090085862A1 (en) Video displaying apparatus
JP2009134237A (en) Display device
JP5132763B2 (en) Liquid crystal image display device
EP2405669A1 (en) Display device, shutter device, shutter control circuit, shutter control method, and display system
TWI419550B (en) Shutter glasses and method for controlling shutter glasses
US20120092331A1 (en) Liquid crystal display device and method of controlling liquid crystal display device
JP2008299191A (en) Image display device
TWI413804B (en) 3d video display method and system for enhancing black frame insertion effect
WO2011148677A1 (en) Liquid crystal display device
JP6896507B2 (en) Display device and its control method
WO2011148684A1 (en) Liquid crystal display device
WO2013046984A1 (en) Liquid crystal display device

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 12869434

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 12869434

Country of ref document: EP

Kind code of ref document: A1