WO2011021688A1 - Dispositif d'affichage à cristaux liquides et récepteur de télévision - Google Patents

Dispositif d'affichage à cristaux liquides et récepteur de télévision Download PDF

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Publication number
WO2011021688A1
WO2011021688A1 PCT/JP2010/064069 JP2010064069W WO2011021688A1 WO 2011021688 A1 WO2011021688 A1 WO 2011021688A1 JP 2010064069 W JP2010064069 W JP 2010064069W WO 2011021688 A1 WO2011021688 A1 WO 2011021688A1
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WIPO (PCT)
Prior art keywords
liquid crystal
gradation
crystal element
backlight
light source
Prior art date
Application number
PCT/JP2010/064069
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English (en)
Japanese (ja)
Inventor
基行 鬼木
高倉　英一
Original Assignee
シャープ株式会社
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Publication date
Priority claimed from JP2009226733A external-priority patent/JP2011075800A/ja
Priority claimed from JP2010184192A external-priority patent/JP2011065151A/ja
Application filed by シャープ株式会社 filed Critical シャープ株式会社
Publication of WO2011021688A1 publication Critical patent/WO2011021688A1/fr

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    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
    • G09G3/3406—Control of illumination source
    • G09G3/342—Control of illumination source using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—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
    • G09G3/36—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 using liquid crystals
    • G09G3/3611—Control of matrices with row and column drivers
    • G09G3/3648—Control of matrices with row and column drivers using an active matrix
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • G02F1/133601—Illuminating devices for spatial active dimming
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • G02F1/133602—Direct backlight
    • G02F1/133603—Direct backlight with LEDs
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F2203/00—Function characteristic
    • G02F2203/30—Gray scale
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2310/00—Command of the display device
    • G09G2310/02—Addressing, scanning or driving the display screen or processing steps related thereto
    • G09G2310/024—Scrolling of light from the illumination source over the display in combination with the scanning of the display screen
    • 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
    • G09G2320/02—Improving the quality of display appearance
    • G09G2320/0252—Improving the response speed
    • 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
    • G09G2320/04—Maintaining the quality of display appearance
    • G09G2320/041—Temperature compensation
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2340/00—Aspects of display data processing
    • G09G2340/16—Determination of a pixel data signal depending on the signal applied in the previous frame

Definitions

  • the present invention relates to a liquid crystal display device and a television receiver including a liquid crystal panel and a backlight light source, and in particular, a technique for preventing the occurrence of white light and a decrease in visibility due to an excessive response of the liquid crystal element,
  • the present invention relates to a technique for improving responsiveness and preventing motion blur and multiple contours in moving image display.
  • a liquid crystal display device including a liquid crystal panel and a backlight light source has been widely used in applications such as a television receiver and a display device.
  • the liquid crystal display device adjusts the display gradation (transmittance) of each liquid crystal element by a voltage applied to each liquid crystal element corresponding to each pixel of the liquid crystal panel.
  • this liquid crystal display device there is a problem of motion blur that occurs during moving image display due to hold driving that always turns on the backlight light source or response delay of the liquid crystal element.
  • a method for preventing motion blur that occurs when displaying a moving image by intermittently lighting a backlight light source within one frame period (one vertical period) to approximate it to impulse driving (For example, refer to Patent Document 1).
  • an alternate long and short dash line shown in FIG. 5 indicates that when the display gradation of the liquid crystal element is changed from “0” gradation to “128” gradation with high whiteness in a normally black liquid crystal display device.
  • an over-response occurs in the liquid crystal element, so that the display gradation can be changed rapidly to reach the target gradation quickly, and motion blur and multiple contours in video display can be reduced. Can be prevented.
  • the overresponse generated in the liquid crystal element when the whiteness of the display gradation of the liquid crystal element is increased is too strong, a problem of so-called whitening that the liquid crystal element appears to shine instantaneously occurs. Therefore, it is necessary to set the strength of the over-response of the liquid crystal element in consideration of the trade-off relationship between the improvement of the response of the liquid crystal element and the prevention of white light, and the response of the liquid crystal element should be sufficiently enhanced. I could not.
  • the solid line shown in FIG. 5 shows the gradation transition when the over-response of the liquid crystal element is weakened to prevent the occurrence of white light. In this case, the gradation change of the liquid crystal element gradually changes.
  • the display gradation of the liquid crystal element cannot reach the target gradation quickly. If the responsiveness of the liquid crystal element is low, there arises a problem that adverse effects such as motion blur and multiple contours of moving image display occur. In addition, when the whiteness of the display gradation of the liquid crystal element is lowered, it is conceivable to cause the liquid crystal element to over-response (undershoot) and to change the gradation quickly. If the overresponse is too strong, a problem arises that the liquid crystal element becomes too dark instantaneously and visibility is lowered (hereinafter referred to as “visibility degradation problem”).
  • a first object of the present invention is to improve the responsiveness of the liquid crystal element as much as possible within a range that can prevent the occurrence of white light and a problem of deterioration in visibility depending on the situation.
  • An object of the present invention is to provide a liquid crystal display device and a television receiver capable of preventing motion blur and multiple contours in moving image display.
  • the present invention comprises a liquid crystal panel, a backlight light source, a liquid crystal drive control means, and a backlight control means.
  • the liquid crystal drive control means is provided on the liquid crystal panel.
  • the liquid crystal element when the intermittent lighting process of the backlight light source is executed by the backlight control unit is compared with the case where the intermittent lighting process is not executed.
  • the liquid crystal display device is characterized in that an applied voltage that increases an excessive response in the change direction of the display gradation is applied to the liquid crystal element.
  • the backlight control means intermittently lights the backlight light source so that the backlight light source is turned off during at least a part of the over-response period of the liquid crystal element.
  • the backlight control unit turns on the light source for a predetermined time after the backlight light source is turned off for a predetermined time from the start of the response period of the liquid crystal element or slightly before the start of the response period of the liquid crystal element.
  • the present invention comprises a liquid crystal panel, a backlight light source, liquid crystal drive control means, and backlight control means, and the liquid crystal drive control means comprises the liquid crystal display.
  • the backlight control means When the display gradation of the liquid crystal element of the panel is changed, an applied voltage that causes an overresponse in the change direction of the display gradation is applied to the liquid crystal element, and the backlight control means
  • the backlight light source is intermittently turned on so that the backlight light source is turned off during at least a part of the over-response period.
  • the backlight control means turns off the backlight light source for a predetermined time and turns it on for a predetermined time from the start of the response period of the liquid crystal element or slightly before the start of the response period of the liquid crystal element. It can be considered a thing.
  • the intermittent lighting is performed. It is desirable to apply an applied voltage to the liquid crystal element that makes an excessive response in the change direction of the display gradation of the liquid crystal element stronger than when the process is not executed. Specifically, the intermittent lighting process is not executed by the backlight control means when the liquid crystal drive control means changes the display gradation of the liquid crystal element to a target gradation having a higher whiteness than the current level.
  • a first applied voltage set in advance corresponding to each combination before and after the change in display gradation of the liquid crystal element is applied to the liquid crystal element, and the intermittent lighting process is executed by the backlight control means.
  • a second applied voltage set in advance so that the whiteness of the liquid crystal element is higher than the first applied voltage is applied to the liquid crystal element.
  • the first applied voltage set in advance corresponding to each combination before and after the change of the display gradation of the liquid crystal element is applied to the liquid crystal element, and the intermittent lighting process is executed by the backlight control means.
  • a third applied voltage set in advance so that the whiteness of the liquid crystal element is lower than the first applied voltage is applied to the liquid crystal element.
  • the intermittent lighting process of the backlight light source when executed, for example, the first applied voltage is increased in order to increase the overresponse of the liquid crystal element compared to the case where the intermittent lighting process is not executed.
  • the second applied voltage or the third applied voltage set in advance so that the whiteness of the liquid crystal element is higher or lower than that is applied to the liquid crystal element.
  • the first gradation correspondence information in which the index value of the first applied voltage corresponding to the combination before and after the change of the display gradation of the liquid crystal element is set, and at least the display gradation of the liquid crystal element Gradation correspondence that stores the second applied voltage index value and / or the second applied voltage index value corresponding to a part of the combination before and after the change of the second applied voltage And further comprising an information storage means.
  • the liquid crystal drive control means changes the display gradation of the liquid crystal element, if the intermittent lighting process is not executed by the backlight control means, the gradation When the first applied voltage is applied to the liquid crystal element based on the first gradation correspondence information stored in the correspondence information storage means, and the intermittent lighting process is executed by the backlight control means.
  • the intermittent lighting process executed by the backlight control means may be a backlight scan process in which the plurality of light sources are sequentially intermittently turned on within one frame period.
  • the backlight scanning process is to intermittently turn on the plurality of light sources sequentially in synchronization with at least a vertical synchronizing signal.
  • the plurality of light sources are turned off for a predetermined time from the start of image writing in a display area corresponding to each of the light sources, and then turned on for a predetermined time.
  • Each of the light sources may include, for example, a plurality of LED light sources arranged in parallel in the horizontal direction of the liquid crystal panel.
  • a television receiver including the liquid crystal display device can also be said to be the present invention.
  • the first applied voltage is increased in order to increase the overresponse of the liquid crystal element compared to the case where the intermittent lighting process is not performed.
  • the second applied voltage or the third applied voltage set in advance so that the whiteness of the liquid crystal element is higher or lower than that is applied to the liquid crystal element, whitening of the liquid crystal element is prevented.
  • the responsiveness of the liquid crystal element can be improved as compared with the case where the intermittent lighting process is not performed, and for example, motion blur and multiple contours of moving image display can be improved.
  • the backlight light source is intermittently turned on so that the backlight light source is extinguished during at least a part of the over-response period of the liquid crystal element. Generation can be improved.
  • FIG. 1 is a block diagram showing a schematic configuration of a liquid crystal display device according to an embodiment of the present invention.
  • the schematic diagram which shows an example of the backlight light source provided in the liquid crystal display device which concerns on embodiment of this invention.
  • FIG. 6 is a diagram showing an example of first and second gradation correspondence information used in the liquid crystal display device according to the embodiment of the present invention.
  • FIG. 6 is a diagram for explaining an example of gradation transition of a liquid crystal element.
  • FIG. 6 is a diagram for explaining an example of gradation transition of a liquid crystal element.
  • FIG. 6 is a diagram for explaining an example of gradation transition of a liquid crystal element.
  • FIG. 5 is a diagram illustrating an example of second gradation correspondence information used in the liquid crystal display device according to the first embodiment of the invention.
  • FIG. 10 is a diagram for explaining an example of the execution result of backlight scan processing in the liquid crystal display device according to the second embodiment.
  • FIG. 6 is a diagram for explaining an example of gradation transition of a liquid crystal element.
  • FIG. 6 is a diagram for explaining an example of gradation transition of a liquid crystal element.
  • compatible information The figure which shows an example of gradation corresponding
  • the figure which shows an example of light extinction period setting information The figure for demonstrating an example of the gradation transition of a liquid crystal element, and the intermittent lighting process of a backlight light source. The figure for demonstrating an example of the gradation transition of a liquid crystal element, and the intermittent lighting process of a backlight light source. The figure for demonstrating an example of the gradation transition of a liquid crystal element, and the intermittent lighting process of a backlight light source.
  • a liquid crystal display device X includes a display control unit 11, a liquid crystal panel 21, a liquid crystal drive unit 22 (an example of liquid crystal drive control means), a backlight light source 31, and a backlight.
  • a control unit 32 (an example of a backlight control unit) is included.
  • the liquid crystal display device X is, for example, a display device used for a television receiver or a personal computer. That is, the present invention can be understood as an invention of a television receiver configured to include the liquid crystal display device X. Note that in this embodiment, description of other components included in a general television receiver or display device that does not directly affect the present invention is omitted.
  • the display control unit 11 receives a video signal included in a television broadcast received by an antenna (not shown) or a video content input from an external input terminal (not shown), and performs vertical synchronization based on the video signal. Signals and horizontal sync signals are generated.
  • the liquid crystal display device X an image based on an image signal such as television broadcast is displayed on the liquid crystal panel 21. Therefore, it can be said that the liquid crystal display device X itself is a television receiver.
  • the video signal, the vertical synchronization signal, and the horizontal synchronization signal are input from the display control unit 11 to the liquid crystal driving unit 22.
  • the display control unit 11 inputs the vertical synchronization signal and the horizontal synchronization signal to the backlight control unit 32.
  • the display control unit 11 generates a vertical synchronizing signal having a driving frequency of 120 Hz which is a double speed of 60 Hz, which is a frequency of a video signal of television broadcasting. Therefore, the display control unit 11 outputs one frame image in the video signal to the liquid crystal drive unit 22 twice, or generates an interpolated image from two consecutive frames in the video signal, Inserted and output to the liquid crystal drive unit 22.
  • the speed is not limited to 2 ⁇ speed, and may be 1 ⁇ speed, 4 ⁇ speed, 8 ⁇ speed, or the like.
  • the backlight source 31 is disposed on the back surface of the liquid crystal panel 21 and illuminates the liquid crystal panel 21 from behind.
  • FIG. 2 is a schematic diagram showing an example of the structure of the backlight light source 31.
  • the backlight source 31 includes a plurality of LED light source groups L1 to L12 (an example of a plurality of light sources) arranged in parallel corresponding to a plurality of display areas in the vertical direction of the liquid crystal panel 21.
  • Each of the LED light source groups L1 to L12 includes a plurality of LED light sources 31a arranged in parallel in the horizontal direction of the liquid crystal panel 21.
  • Each of the display areas corresponding to the LED light source groups L1 to L12 is an area including a plurality of lines of display pixels of the liquid crystal panel 21.
  • the backlight light source 31 individually blinks a large number of the LED light sources 31a in units of the LED light source groups L1 to L12.
  • the number of the LED light source groups L1 to L12 is not limited to this, and the design may be appropriately changed according to the size of the liquid crystal panel 21.
  • the backlight light source 31 may include a plurality of fluorescent tubes (an example of a plurality of light sources) arranged in parallel in the vertical direction of the liquid crystal panel 21 instead of the LED light source groups L1 to L12. .
  • the backlight control unit 32 is linked to the hold driving process for always lighting the backlight light source 31 and the image signal writing operation by the liquid crystal driving unit 22 within one frame period (one vertical period).
  • One of a backlight scanning process (an example of an intermittent lighting process) in which the LED light source 31a of the backlight light source 31 is intermittently turned on sequentially for each of the LED light source groups L1 to L12 is selectively executed.
  • the backlight control unit 32 may always execute the backlight scan processing. Whether or not the backlight control process is executed by the backlight control unit 32 is switched by the display control unit 11 according to a user operation of an operation key provided on a remote controller (not shown) or the main body of the liquid crystal display device X, for example. It is done.
  • the display control unit 11 may automatically switch the execution of the backlight scan process according to the content of the display video.
  • one frame period is a period for displaying an image of one frame on the liquid crystal panel 21, that is, an interval of vertical synchronizing signals. Therefore, in the liquid crystal display device X in which the image writing speed (driving frequency) of the liquid crystal panel 21 is 120 Hz (so-called double speed liquid crystal), one frame period is about 8.3 ms.
  • the driving frequency of the liquid crystal panel 15 may be 60 Hz or 240 Hz.
  • FIG. 3 is a schematic diagram for explaining an example of the execution result of the backlight scan processing, where (a) is a vertical synchronization signal, (b) is an image signal, and (c) is a backlight light source. 31 operations are shown.
  • the LED light source groups L1 to L12 are received after the vertical synchronization signal (see FIG. 3A) is received. Each is turned off for about 4.1 ms (50% of one frame) from the start of image writing of the image signal of one frame in the corresponding display area (see FIG. 3B), and then about 4.1 ms (50 of one frame). %)Light.
  • the time (ratio) during which the LED light source groups L1 to L12 are turned off or turned on is not limited to this.
  • the backlight control unit 32 sequentially blinks each of the LED light source groups L1 to L12 in synchronization with the vertical synchronization signal and horizontal synchronization signal of the image signal displayed on the liquid crystal panel 21 in the backlight scanning process.
  • the backlight scanning process may be performed in synchronization with at least writing of the image signal by the liquid crystal driving unit 22 in synchronization with the vertical synchronization signal.
  • the backlight control unit 32 turns off the LED light source group L1 in the first row for about 4.1 ms by receiving the horizontal synchronization signal in the first row after receiving the vertical synchronization signal, and then about 4. Turn on for 1 ms.
  • the backlight control unit 32 receives the horizontal synchronization signal corresponding to the number of lines existing in the display area of the liquid crystal panel 21 corresponding to the LED light source group L1 after receiving the vertical synchronization signal.
  • the LED light source group L2 is turned off for about 4.1 ms, and then turned on for about 4.1 ms.
  • the backlight control unit 32 receives horizontal synchronization signals for the number of lines existing in the display area of the liquid crystal panel 21 corresponding to the LED light source groups L1 and L2. Further, the next LED light source group L3 is turned off for about 4.1 ms, and then turned on for about 4.1 ms. Thereafter, the same processing is repeated, so that the LED light source groups L1 to L12 are sequentially blinked in synchronization with the scanning of the liquid crystal elements of a plurality of lines of the liquid crystal panel 21 corresponding thereto.
  • the liquid crystal panel 21 includes a plurality of liquid crystal elements that are formed by a liquid crystal layer and a scan electrode and a data electrode for applying a scan signal and a data signal to the liquid crystal layer, and whose transmittance varies depending on the applied voltage.
  • This is a known active matrix liquid crystal panel.
  • the liquid crystal driving unit 22 applies scanning electrodes (gate electrodes) and data electrodes (source electrodes) of the liquid crystal panel 21 based on an image signal, a vertical synchronization signal, and a horizontal synchronization signal input from the display control unit 11. Drive.
  • the liquid crystal driving unit 22 After receiving the vertical synchronizing signal, the liquid crystal driving unit 22 outputs a gate signal to the scanning electrode in accordance with the horizontal synchronizing signal corresponding to the first line, and receives the image signal corresponding to the first line as data. Output sequentially to the electrodes. As a result, the first line image is displayed. Thereafter, when the horizontal synchronizing signal corresponding to the second line is input, the liquid crystal driving unit 22 outputs a gate signal to the scanning electrode of the second line, and sequentially applies the image signal corresponding to the second line to the data electrode. Output. Thereafter, the same processing is repeated to display an image on the full screen of the liquid crystal panel 21.
  • the liquid crystal driving unit 22 controls the voltage applied to each liquid crystal element corresponding to each pixel of the liquid crystal panel 21 based on the image signal input from the display control unit 11, thereby The transmittance of illumination from the backlight light source 31 of each element is changed, and the display gradation of each liquid crystal element is controlled. Note that when the backlight scanning process is executed, the luminance of the backlight light source 31 decreases, so that the display control unit 11 applies the liquid crystal element of the liquid crystal panel 21 depending on whether or not the backlight scanning process is executed. The display luminance is kept constant by correcting the level of the video signal to be written. It is also conceivable that the liquid crystal driving unit 22 appropriately changes the gamma characteristic that defines the relationship between the image signal and the applied voltage in accordance with the correction of the level of the video signal.
  • the liquid crystal driving unit 22 includes a nonvolatile storage memory 23 (floor) in which two look-up tables T1 and T2 (see FIGS. 4A and 4B, hereinafter abbreviated as “tables T1 and T2”) are stored.
  • An adjustment information storage means controls the voltage applied to the liquid crystal element based on one of the tables T1 and T2 stored in the storage memory 23.
  • the liquid crystal driving unit 22 controls the voltage applied to the liquid crystal element based on the tables T1 and T2, thereby changing the display gradation of the liquid crystal element of the liquid crystal panel 21.
  • the tables T1 and T2 have index gradations serving as index values of applied voltages corresponding to combinations before and after the change in display gradation of the liquid crystal element. It is set in advance. Each of the index gradations in the tables T1 and T2 may be set according to the results of experiments and simulations performed in advance. Of course, the value of the applied voltage may be set instead of the index gradation. It is assumed that the liquid crystal display device X according to the present embodiment is a normally black system in which 0 gradation is black and 255 gradation is white. That is, the higher the voltage applied to the liquid crystal element, the higher the whiteness of the display gradation of the liquid crystal element.
  • the index gradation corresponding to the combination when the display gradation of the liquid crystal element of the liquid crystal panel 21 is changed in the direction of increasing whiteness is set higher than the target gradation at that time. For example, when the current gradation is “0” gradation and the target gradation is “128” gradation, “145” gradation higher than the target gradation “128” gradation is the index. It is set as a gradation. However, in the table T1, the index gradation is set to be low in consideration of preventing white light caused by excessive response of the liquid crystal element.
  • the table T1 is an example of first gradation correspondence information.
  • the table T2 corresponds to a combination in the case where the display gradation of the liquid crystal elements of the liquid crystal panel 21 is changed in the direction of increasing whiteness, as in the table T1.
  • the index gradation is set to a gradation higher than the target gradation at that time, and the index gradation is higher in whiteness of the liquid crystal element than the index gradation corresponding to the same combination in the table T1. It is a value set in advance so as to increase. That is, when the table T2 is used, the applied voltage supplied to the liquid crystal element when the display gradation of the liquid crystal element of the liquid crystal panel 21 is changed in the direction of increasing whiteness is higher than that of the table T1. Get higher.
  • the table T2 is an example of second gradation correspondence information.
  • the liquid crystal driving unit 22 switches and refers to the tables T1 and T2 depending on whether or not the backlight control process of the backlight light source 31 is performed by the backlight control unit 32, and applies it to the liquid crystal element. Control the voltage.
  • the liquid crystal driving unit 22 determines whether or not the backlight scanning process is executed by the backlight control unit 32 based on, for example, a control signal transmitted from the display control unit 11 or the backlight control unit 32. It is possible to judge.
  • the liquid crystal driving unit 22 performs a backlight scan of the backlight light source 31 by the backlight control unit 32 when changing the display gradation of the liquid crystal element to a display gradation having higher whiteness than the current level.
  • the voltage applied to the liquid crystal element is controlled based on the table T1 stored in the storage memory 23, and the backlight control unit 32 controls the backlight of the backlight light source 31.
  • the voltage applied to the liquid crystal element is controlled based on the table T2 stored in the storage memory 23.
  • the backlight control unit 32 always executes backlight scanning processing, only the table T2 is stored in the storage memory 23 in advance, and the liquid crystal driving unit 22 always performs the table T2. It is also conceivable to control the voltage applied to the liquid crystal element based on the above.
  • FIG. 5 shows a case where the liquid crystal driving unit 22 controls the voltage applied to the liquid crystal element based on the table T1 in a state where the backlight scanning process is not executed by the backlight control unit 32.
  • 2 shows an example of gradation transition of the liquid crystal element.
  • the liquid crystal driving unit 22 compares the current gray level and the target gray level of each of the liquid crystal elements by comparing the currently input image signal of one frame with the previously input image signal of one frame. (The combination before and after the change) is detected, and the applied voltage corresponding to the combination is extracted from the table T1 and supplied to the liquid crystal element.
  • the liquid crystal drive unit 22 holds at least one previous frame image signal.
  • the liquid crystal driving unit 22 extracts “145”, which is an index gradation corresponding to the combination thereof, from the table T1. .
  • the liquid crystal driving unit 22 supplies the liquid crystal element with an applied voltage (corresponding to the first applied voltage) corresponding to the index gradation “145” to change the display gradation of the liquid crystal element (FIG. 5). Solid line).
  • the liquid crystal driving unit 22 supplies the liquid crystal element with an applied voltage corresponding to “128” as the target gradation.
  • the responsiveness of the liquid crystal element can be improved as compared with the case where the applied voltage corresponding to the target gradation “128” gradation is supplied.
  • the table T1 since the index gradation is set to be low in consideration of preventing the occurrence of white light due to excessive response of the liquid crystal element, the response of the liquid crystal element is sufficiently increased. It is hard to say that it can be increased. 5 is a case where the voltage applied to the liquid crystal element is controlled based on the table T2 in a state where the backlight scanning process is not executed by the backlight control unit 32, that is, The gradation transition when the applied voltage corresponding to the “160” gradation is applied is shown.
  • the gradation transition is abruptly caused by the over-response of the liquid crystal element, the gradation transition of the liquid crystal element can be performed quickly, but the white light caused by the over-response of the liquid crystal element can be reduced. With problems.
  • the liquid crystal driving unit 22 controls the voltage applied to the liquid crystal element based on the table T2 in a state where the backlight scanning process is being executed by the backlight control unit 32.
  • An example of gradation transition of the liquid crystal element in the case is shown.
  • the liquid crystal driving unit 22 extracts “160” that is an index gradation corresponding to the combination from the table T2. .
  • the liquid crystal driving unit 22 supplies an applied voltage (corresponding to the second applied voltage) corresponding to the index gradation “160” to the liquid crystal element to change the display gradation of the liquid crystal element.
  • the liquid crystal driving unit 22 supplies the liquid crystal element with an applied voltage corresponding to “128” as the target gradation.
  • the gradation transition of the liquid crystal element is performed more rapidly than when the table T1 is used (the one-dot chain line in FIG. 6). For example, motion blur and multiple contours in moving image display can be prevented.
  • the backlight scanning process is executed by the backlight control unit 32 and the backlight light source 31 is intermittently lit, the backlight is within one frame period.
  • the LED light source groups L1 to L12 of the backlight light source 31 are turned on for about 4.1 ms after being turned off for about 4.1 ms from the start of image writing in the corresponding display area. That is, the backlight control unit 32 turns off each of the LED light source groups L1 to L12 for a predetermined time from the start of the response period of the liquid crystal element of the liquid crystal panel 21, and then turns it on for a predetermined time.
  • the backlight scanning process (intermittent lighting) of each of the LED light source groups L1 to L12 is executed so that each of the LED light source groups L1 to L12 is turned off during at least a part of the over-response period. Therefore, it is possible to effectively suppress the influence of the peak portion of the overresponse of the liquid crystal element on the white light.
  • the backlight control unit 32 when the liquid crystal driving unit 22 changes the display gradation of the liquid crystal element to a display gradation having a higher whiteness than the current level, the backlight control unit 32.
  • the applied voltages (each corresponding to each combination before and after the change of the display gradation of the liquid crystal element based on the table T1). (First applied voltage) is applied to the liquid crystal element, and when the backlight control unit 32 is executing backlight scanning processing (intermittent lighting processing) of the backlight light source 31, it is applied to the table T1.
  • An applied voltage (second applied voltage) set in advance so that the whiteness of the liquid crystal element is higher than the voltage is applied to the liquid crystal element. That is, the liquid crystal driving unit 22 changes the display gradation of the liquid crystal element, and if the backlight control unit 32 is executing the intermittent lighting process of the backlight light source 31, the intermittent lighting process is performed.
  • An applied voltage is applied to the liquid crystal element in which the overresponse in the change direction of the display gradation of the liquid crystal element is stronger than when the liquid crystal element is not executed. Accordingly, when the backlight control process of the backlight light source 31 is executed by the backlight control unit 32, the liquid crystal element can be controlled in response to the backlight scan while the white light of the liquid crystal element is prevented. Compared to the case where the process is not executed, it is possible to improve, for example, motion blur and multiple contours in moving image display.
  • the method of controlling the voltage applied to the liquid crystal element by the liquid crystal driving unit 22 is not limited to using the tables T1 and T2, and a predetermined calculation is performed for combinations before and after the change in display gradation of the liquid crystal element. It is also conceivable to control the voltage applied to the liquid crystal element by performing the above.
  • the table T2 may be a table in which only a portion different from the table T1 is set.
  • the display control unit 11 performs the backlight control by the backlight control unit 32 on the condition that the table T2 is selected.
  • the switching is automatically performed so that the execution of the scanning process becomes effective.
  • each of the LED light sources 31a of the backlight light source 31 blinks for each of the LED light source groups L1 to L12
  • all the LED light sources 31a blink simultaneously.
  • the present invention can also be applied to the configuration.
  • the case where the liquid crystal display device X is a normally black system has been described as an example.
  • the present invention can also be applied to a normally white system.
  • the applied voltage set to a low value so that the whiteness of the liquid crystal element is higher than the normal applied voltage (first applied voltage)
  • the second applied voltage is supplied to the liquid crystal element as an overshoot voltage.
  • the responsiveness (response speed) of the liquid crystal element in the liquid crystal panel 21 depends on the temperature. Therefore, a temperature sensor for detecting the temperature of the liquid crystal panel 21 is provided, and a plurality of tables corresponding to the temperature are prepared, and the tables T1 and T2 are changed to tables corresponding to the temperature detected by the temperature sensor. It is also possible to do. Specifically, for each of the tables T1 and T2, a plurality of tables corresponding to each temperature in a predetermined range are preset and stored in the storage memory 23, and the liquid crystal driving unit 22 is controlled by the temperature sensor. It is conceivable that a table corresponding to the range to which the detected temperature belongs is extracted from the storage memory 23 and the applied voltage of the liquid crystal element is controlled based on the table.
  • the liquid crystal driving unit 22 switches which of the plurality of tables is used by comparing the temperature detected by the temperature sensor with a predetermined threshold, the detected temperature is subtly close to the predetermined threshold.
  • the liquid crystal driving unit 22 performs the selection control process of the table based on the predetermined threshold value with hysteresis. This prevents frequent switching of the table to be used even when the detected temperature changes slightly.
  • the liquid crystal display device X according to the present embodiment has been described on the assumption that an image is displayed as a planar image (2D).
  • the present invention can also be applied to a liquid crystal display device capable of displaying a stereoscopic (3D) video by allowing a viewer to view a stereoscopic video by displaying the left-eye video and the right-eye video in a time-sharing manner.
  • a liquid crystal display device capable of displaying stereoscopic images similarly, when performing a backlight scan operation, the degree of overresponse (OS parameter) of the liquid crystal element may be changed. As a result, the response performance of the liquid crystal can be improved even in a liquid crystal display device capable of displaying a stereoscopic image.
  • OS parameter overresponse
  • the liquid crystal element when the display gradation of the liquid crystal element is changed to a display gradation having a higher whiteness than the current level, the liquid crystal element is overresponsive in the direction of increasing the display gradation.
  • the liquid crystal display device X when the liquid crystal driving unit 22 changes the display gradation of the liquid crystal element to a display gradation having higher whiteness than the current level, the liquid crystal element has a direction in which the display gradation becomes higher.
  • the display gradation of the liquid crystal element is changed to a display gradation whose whiteness is lower than the current level, the display gradation of the liquid crystal element is lowered.
  • a lookup table T3 similar to the tables T1 and T2 (see FIG. 4) (an example of second gradation correspondence information, hereinafter abbreviated as “table T3”).
  • table T3 an example of second gradation correspondence information, hereinafter abbreviated as “table T3”.
  • the liquid crystal driving unit 22 controls the voltage applied to the liquid crystal element based on the tables T1 to T3 or T1 and T3 stored in the storage memory 23.
  • a table an example of second gradation correspondence information obtained by combining them may be used.
  • the table T3 shows the index gradation corresponding to the combination when the display gradation of the liquid crystal element of the liquid crystal panel 21 is changed in the direction of decreasing whiteness.
  • the index gradation is set in advance so that the whiteness of the liquid crystal element is lower than the index gradation corresponding to the same combination in the table T1. Value. That is, when the table T3 is used, the applied voltage supplied to the liquid crystal element when the display gradation of the liquid crystal element of the liquid crystal panel 21 is changed in the direction in which the whiteness decreases is obtained from the table T1. Also lower.
  • the index gradation is set as a key.
  • the table T1 is set in consideration of preventing the deterioration in visibility caused by the excessive response of the liquid crystal element.
  • the table T1 is an example of first gradation correspondence information.
  • a gradation lower than the target gradation may be set as the index gradation so as not to cause a problem of deterioration in visibility.
  • the liquid crystal driving unit 22 changes the display gradation of the liquid crystal element to a display gradation whose whiteness is lower than the current level, and the backlight control unit 32 performs backlight scanning processing ( When the intermittent lighting process is not executed, an applied voltage (first applied voltage) corresponding to each combination before and after the change in display gradation of the liquid crystal element is applied to the liquid crystal element based on the table T1.
  • an applied voltage first applied voltage
  • the backlight control unit 32 performs a backlight scan process (intermittent lighting process) of the backlight light source 31, the whiteness of the liquid crystal element is lower than the applied voltage in the table T1.
  • a preset applied voltage (third applied voltage) is applied to the liquid crystal element.
  • the liquid crystal driving unit 22 changes the display gradation of the liquid crystal element, and if the backlight control unit 32 is executing the intermittent lighting process of the backlight light source 31, the intermittent lighting process is performed.
  • An applied voltage is applied to the liquid crystal element in which the overresponse in the change direction of the display gradation of the liquid crystal element is stronger than when the liquid crystal element is not executed.
  • the backlight scanning process of the backlight light source 31 is executed by the backlight control unit 32, the gradation transition of the liquid crystal element is performed more rapidly than when the table T1 is used. As a result, the response of the liquid crystal element can be sufficiently enhanced. Further, in this case, since the backlight light source 31 is intermittently turned on by the backlight scanning process, there is a turn-off time of the backlight light source 31 within one frame period, and the liquid crystal element is over-reacted. The problem that visibility becomes low due to being too dark is also reduced.
  • the liquid crystal element is overresponsive in the direction of lowering the display gradation, thereby causing the liquid crystal element to In both the case where the display gradation of the element is changed to a high degree of whiteness and the case where the display gradation is changed to a low degree, the response of the liquid crystal element can be sufficiently improved while preventing the occurrence of whiteness and a problem of deterioration in visibility.
  • the backlight control unit 32 starts image writing to each of the LED light source groups L1 to L12 and to the liquid crystal elements in the display area of the liquid crystal panel 21 corresponding to each of the LED light source groups L1 to L12. It is conceivable to execute a backlight scan process in which the light is turned off for a predetermined time slightly before the start of response of the liquid crystal element, and then turned on for a predetermined time.
  • the backlight control unit 32 divides the LED light source groups L1 to L12 of the backlight light source 31 into four divided LED light source groups L21 to L24. It is assumed that backlight scanning processing (intermittent lighting) is performed to blink in order.
  • FIG. 9 shows the relationship between the extinguishing period in the LED light source group L21 and the response period of the liquid crystal elements in the display area corresponding to the LED light source group L21.
  • 9A shows a vertical synchronizing signal
  • FIG. 9B shows an image signal
  • FIGS. 9C to 9E show driving states of the liquid crystal element.
  • FIGS. 9C to 9E show a case where the display gradation of the liquid crystal element is changed from “0” to “128”.
  • FIG. 9C when a voltage corresponding to the target gradation is applied to the liquid crystal element, the response speed of the liquid crystal element becomes slow.
  • FIG. 9C when a voltage corresponding to the target gradation is applied to the liquid crystal element, the response speed of the liquid crystal element becomes slow.
  • FIG. 9C when a voltage corresponding to the target gradation is applied to the liquid crystal element, the response speed of the liquid crystal element becomes slow.
  • FIG. 9C when a voltage corresponding to the target gradation is applied
  • the response speed of the liquid crystal element when a voltage higher than the voltage corresponding to the target gradation is applied to the liquid crystal element, the response speed of the liquid crystal element can be increased.
  • the response speed of the liquid crystal element in order to prevent motion blur and multiple contours that occur during moving image display in the liquid crystal display device X, it is desirable that the response speed of the liquid crystal element be as fast as possible. Therefore, as shown in FIG. It is conceivable that the liquid crystal element is caused to have an excessive response by increasing it further. However, in this case, problems such as whiteness occur due to the excessive response. Therefore, it is desirable that the LED light source group L21 be turned off as long as possible during the overresponse period of the liquid crystal element so as not to show the overresponse of the liquid crystal element.
  • FIG. 10 shows the LED light source for a predetermined time from the start of image writing to the liquid crystal element in the display area corresponding to the LED light source group L21 (response start of the liquid crystal element) as described in the embodiment.
  • the LED light source group L21 is turned on for a predetermined time after the group L21 is turned off.
  • the LED light source groups L1 to L12 of the backlight light source 31 are blinked in order for each of the four divided LED light source groups L21 to L24.
  • the display area corresponding to L24 is widened. For this reason, as shown in FIGS.
  • the backlight control unit 32 slightly before the start of image writing to the liquid crystal element in the display area corresponding to the LED light source group L21, that is, slightly before the response start of the liquid crystal element. Therefore, it is conceivable to execute the backlight scanning process so that the LED light source group L21 is turned off for a predetermined time (4.1 ms) and then turned on for a predetermined time (4.1 ms).
  • the LED light source group L21 can be lengthened during the over-response period of the liquid crystal element as well, and the liquid crystal element at the head part can be lengthened. A big improvement effect about a problem can be acquired.
  • the LED light source group L21 is turned off during the over-response period of the liquid crystal elements at the middle and last part, and the white light etc.
  • a big improvement effect is obtained about a problem.
  • FIG. 11E when the time from the start of turning off of the LED light source group L21 to the start of response of the liquid crystal element becomes longer, the response from the start of response of the liquid crystal element to the lighting of the LED light source group L21 is continued. The time becomes short and the state close to the start of the gradation change of the liquid crystal element can be seen.
  • the start position of the LED light source group L21 during the extinguishing period takes into account the trade-off relationship between the effect of preventing white light and the like and the effect of preventing motion blur, for example, the number of light sources that are simultaneously turned on in the backlight scanning process. It is desirable to set appropriately in advance in accordance with (number of divisions), frame period (image writing speed), and the like.
  • the response time of the liquid crystal element also varies depending on the amount of change in display gradation between video frames. For example, the response time of the liquid crystal element becomes longer as the change amount of the display gradation is larger, and the response time of the liquid crystal element becomes shorter as the change amount of the display gradation is smaller. For this reason, the degree of overresponse of the liquid crystal element and the display gradation can be determined only by setting the backlight light source extinction period so that the rise and fall of the liquid crystal element can be completed during the backlight light source extinction period under certain conditions.
  • a liquid crystal panel having a plurality of liquid crystal elements whose transmittance varies depending on the applied voltage, a backlight source that illuminates the liquid crystal panel from behind, and the liquid crystal panel by controlling the voltage applied to the liquid crystal element.
  • Liquid crystal drive control means for controlling the display gradation of the element, and backlight control means for executing intermittent lighting processing for intermittently lighting the backlight light source.
  • the response time of the liquid crystal element when the display gradation is controlled by the liquid crystal drive control means so that the rise and / or fall of a part or all of the liquid crystal elements in the liquid crystal panel is completed within the light-off period.
  • the backlight light source is turned off in the intermittent lighting process in accordance with the liquid crystal display device. It is conceivable to.
  • a part of the liquid crystal panel within the backlight light source extinguishing period follows the response time of the liquid crystal element that changes depending on the degree of overresponse of the liquid crystal element, the amount of change in the display gradation, and the like.
  • the rising and falling of all the liquid crystal elements can be terminated, and pseudo contour (moving image blur) can be prevented.
  • the liquid crystal drive control means applies, to the liquid crystal element, an applied voltage that increases an excessive response in the change direction of the display gradation of the liquid crystal element when the display gradation of the liquid crystal element is changed.
  • the backlight control means is responsive to the degree of overresponse in the change direction of the display gradation of the liquid crystal element controlled by the liquid crystal drive control means that the response time of the liquid crystal element changes. It is conceivable that the backlight light source extinguishing period is controlled in the intermittent lighting process.
  • the backlight control unit is configured to perform the intermittent operation according to a change amount of the display gradation of the display gradation of the liquid crystal element that is controlled by the liquid crystal drive control unit that changes a response time of the liquid crystal element. It is also conceivable to control the turn-off period of the backlight light source in the lighting process.
  • the backlight control means controls the degree of overresponse in the change direction of the display gradation of the liquid crystal element and the display gradation controlled by the liquid crystal drive control means in which the response time of the liquid crystal element changes. It is also conceivable that the backlight light source extinguishing period in the intermittent lighting process is controlled in accordance with the amount of change in the above.
  • an extinction period setting information storage in which extinction period setting information that defines the relationship between the degree of overresponse and / or the amount of change in display gradation and the extinction period of the backlight light source in the intermittent lighting process is stored in advance.
  • the backlight control means based on the extinction period setting information stored in the extinction period setting information storage means, the degree of overresponse and / or the amount of change in the display gradation. It is conceivable that the backlight light source is turned off in the intermittent lighting process.
  • the backlight light source includes a plurality of light sources arranged in parallel corresponding to a plurality of display areas in the vertical direction of the liquid crystal panel, the intermittent lighting executed by the backlight control means.
  • the process is a backlight scan process in which the plurality of light sources are sequentially turned on intermittently, and the backlight control unit controls a turn-off period of the backlight light source in the backlight scan process according to a response time of the liquid crystal element. It is thought that it is what to do.
  • the display control unit 11 averages the amount of change in display gradation of the entire liquid crystal panel 21 for each frame of the video signal (hereinafter referred to as “average gradation change amount”). ) For calculating an average gradation change amount.
  • the average gradation change amount calculation function embodied by the display control unit 11 stores the display gradation of each liquid crystal element in at least two consecutive frames in a predetermined storage memory, and each of the liquid crystal elements The average gradation change amount of the entire liquid crystal panel 21 is calculated from the display gradation change amount. It is also possible to calculate the average gradation change amount of three or more consecutive frames as another embodiment. Further, an average gradation change amount of a predetermined part of the liquid crystal panel 21 for each frame of the video signal may be calculated.
  • the liquid crystal drive unit 22 includes a nonvolatile storage memory 23 (see FIG. 1) in which gradation correspondence information T21 to T23 shown in FIGS. 12 to 14 are stored.
  • the liquid crystal drive unit 22 controls the voltage applied to the liquid crystal element based on any one of the gradation correspondence information T21 to T23 stored in the storage memory 23.
  • the gradation correspondence information T21 to T23 includes, as shown in FIGS. 12 to 14, an index gradation that becomes an index value of the applied voltage corresponding to the combination before and after the change of the display gradation of the liquid crystal element is previously stored. It is set.
  • the value of the applied voltage may be set instead of the index gradation.
  • the liquid crystal display device X according to the third embodiment is a normally black system in which the 0 gradation is black and the 255 gradation is white. That is, the higher the voltage applied to the liquid crystal element, the higher the whiteness of the display gradation of the liquid crystal element.
  • the combination corresponding to the case where the display gradation of the liquid crystal element of the liquid crystal panel 21 is changed in the direction of increasing whiteness is set to a gradation higher than the target gradation at that time. Further, the index gradation corresponding to the combination in the case where the display gradation of the liquid crystal element of the liquid crystal panel 21 is changed in the direction of decreasing whiteness is also set to a gradation lower than the target gradation at that time. Yes.
  • the liquid crystal driving unit 22 controls the voltage applied to the liquid crystal element using any one of the gradation correspondence information T21 to T23, the display of the liquid crystal element is changed when the display gradation of the liquid crystal element is changed.
  • An applied voltage that increases the overresponse in the gradation change direction is applied to the liquid crystal element, and an overresponse (overshoot or undershoot) occurs in the liquid crystal element.
  • Each of the index gradations in the gradation correspondence information T21 to T23 may be set according to the results of experiments and simulations performed in advance.
  • the set value of the voltage applied to the liquid crystal element is different, that is, the degree of overresponse of the liquid crystal element is different.
  • the gray scale correspondence information T22 has a greater overresponse of the liquid crystal element than the gray scale correspondence information T21 and T23, and the gray scale correspondence information T23 is more than the gray scale correspondence information T21 and T22.
  • the overresponse of the liquid crystal element is small. That is, the degree of overresponse of the liquid crystal element is gradation correspondence information T23 ⁇ gradation correspondence information T21 ⁇ gradation correspondence information T22.
  • the response time required for the liquid crystal element to stabilize from the current gray level to the target gray level becomes longer as the degree of overresponse of the liquid crystal device increases.
  • Gradation correspondence information T23 ⁇ tone correspondence information T21 ⁇ tone correspondence information T22.
  • the current gradation when the current gradation is “0” gradation and the target gradation is “128” gradation, it is higher than “128” gradation that is the target gradation. “130” gradation is set as the index gradation. Further, when the current gradation is “128” gradation and the target gradation is “64” gradation, “60” gradation lower than the target gradation “64” gradation is the index. It is set as a gradation.
  • the current gradation is “0” gradation and the target gradation is “128” gradation, it is higher than “128” gradation that is the target gradation.
  • “135” gradation is set as the index gradation.
  • the “53” gradation lower than the “64” gradation that is the target gradation is the index. It is set as a gradation.
  • the current gradation is “0” gradation and the target gradation is “128” gradation, it is higher than the “128” gradation that is the target gradation.
  • “129” gradation is set as the index gradation.
  • “63” gradation lower than the target gradation “64” gradation is the index. It is set as a gradation.
  • the liquid crystal driving unit 22 switches and refers to the gradation correspondence information T21 to T23 according to the environmental temperature of the liquid crystal display device X, for example, and controls the voltage applied to the liquid crystal element.
  • the environmental temperature of the liquid crystal display device X is detected by a temperature sensor (not shown) provided in the liquid crystal display device X and input to the display control unit 11 and the liquid crystal driving unit 22.
  • the switching of the gradation correspondence information T21 to T23 is not limited to being performed according to the environmental temperature of the liquid crystal display device X. For example, it is conceivable that the switching is performed according to an arbitrary setting by the user, or the switching is performed according to the service life of the liquid crystal display device X (deterioration of the liquid crystal element).
  • the liquid crystal drive unit 22 transmits to the backlight control unit 32 via the display control unit 11 which one of the gradation correspondence information T21 to T23 is used.
  • the backlight control unit 32 can know the degree of overresponse of the liquid crystal elements of the liquid crystal panel 21.
  • the liquid crystal display device X is characterized in that the light extinction period of the backlight light source 31 in the backlight scanning process is controlled according to the response time of the liquid crystal element.
  • the backlight control unit 32 has a storage memory (an example of a turn-off period setting information storage unit) in which the turn-off period setting information T11 shown in FIG. 15 is stored in advance.
  • the extinction period setting information T11 defines the relationship between the degree of overresponse of the liquid crystal element and the average gradation change amount and the extinction period of the backlight light source 31 in the backlight scan process (intermittent illumination process). Yes.
  • the extinguishing period determined by the extinguishing period setting information corresponds to the degree of overresponse of the liquid crystal element and the content of the average gradation change amount until the rise and fall of the liquid crystal element.
  • the response time is determined as the time to end within the turn-off period of the backlight light source 31.
  • the response time of the liquid crystal element varies depending on the degree of overresponse of the liquid crystal element and the average gradation change amount. Therefore, in the extinction period setting information T11, the extinction period is longer as the degree of overresponse of the liquid crystal element is larger and the response time of the liquid crystal element is longer, and the average gradation change amount is larger and the response time of the liquid crystal element is larger.
  • the backlight control unit 32 refers to the extinction period setting information T11 stored in the storage memory, and determines the degree of overresponse of the liquid crystal element when the display gradation is controlled by the liquid crystal driving unit 22. In response to a response time of the liquid crystal element that changes according to the average gradation change amount, the backlight in the backlight processing is finished so that the liquid crystal element finishes rising or rising within the extinguishing period of the backlight light source 31. The extinguishing period of the light source 31 is controlled.
  • the backlight control unit 32 controls intermittent lighting of the backlight light source 31 in accordance with a high-frequency clock signal generated by a clock generator (not shown) provided in the liquid crystal display device X.
  • the backlight control unit 32 can adjust the length of the turn-off period by changing the turn-off timing in the intermittent turn-on and the count number of the clock signal for measuring the turn-on timing.
  • the backlight control unit 32 can perform finer control than when the blinking of the backlight light source 31 is controlled at a cycle that is an integral multiple of the vertical synchronizing signal of the video signal.
  • the extinction period of the backlight source 31 in the backlight process is controlled in accordance with the change in the response time of the liquid crystal element due to either the degree of overresponse of the liquid crystal element or the average gradation change amount.
  • gradation transition of the liquid crystal element and backlight scan processing of the backlight light source 31 performed in the liquid crystal display device X will be described with reference to FIGS. 16 to 18,
  • (a) is a gradation signal (an index value that determines an applied voltage) corresponding to a certain liquid crystal element provided in the liquid crystal panel 21, and
  • (b) is an actual display floor of the liquid crystal element.
  • Tone transition, (c) indicates ON / OFF (lighting and extinguishing) of the backlight light source 31.
  • the driving frequency of the liquid crystal driving unit 22 is 240 Hz, and the voltage applied to the liquid crystal element can be changed about every 4.1 ms.
  • the display gradation of a certain liquid crystal element is changed from “0” gradation to “128” gradation in the first frame. And then the transition from “128” gradation to “64” gradation in the second frame, and the average gradation change amount of the entire liquid crystal panel 21 corresponding to the first frame is “128”.
  • the case where the average gradation change amount of the entire liquid crystal panel 21 corresponding to the second frame is “64” will be described as an example.
  • the liquid crystal driving unit 22 compares the current gray level and the target gray level of each of the liquid crystal elements by comparing the currently input image signal of one frame with the previously input image signal of one frame. (A combination before and after the change) is detected, and an applied voltage corresponding to the combination is extracted from the gradation correspondence information T21 and supplied to the liquid crystal element. Therefore, the liquid crystal drive unit 22 holds at least one previous frame image signal.
  • the liquid crystal driving unit 22 sets “130”, which is an index gradation corresponding to the combination thereof, to the gradation correspondence information T21.
  • Extract from The liquid crystal driving unit 22 supplies the liquid crystal element with an applied voltage corresponding to the index gradation “130” (see FIG. 16A), and changes the display gradation of the liquid crystal element (see FIG. b)). Then, the liquid crystal driving unit 22 supplies an applied voltage corresponding to “128” as the target gradation to the liquid crystal element (see FIG. 16A). At this time, as shown in FIG. 16 (b), the display gradation of the liquid crystal element should be stabilized after it exceeds the "128" gradation due to overresponse (overshoot) and then decreases to the "128” gradation. It becomes. Therefore, the greater the degree of overresponse of the liquid crystal element, the longer the response time until the liquid crystal element stabilizes to the target gradation, and the shorter the degree of overresponse of the liquid crystal element, the shorter the response time.
  • the backlight control unit 32 responds until the transition of the display gradation of the liquid crystal element is completed, that is, the response time until the liquid crystal element rises and falls. Until the time elapses, the backlight source 31 is turned off. Specifically, for the first frame, the backlight control unit 32 indicates that the liquid crystal driving unit 22 uses the gradation correspondence information T21 and that the average gradation change amount is “128”. , Based on the extinction period setting information T11 (see FIG.
  • the extinguishing period of the backlight source 31 is set to “4.7 ms”. As a result, among the liquid crystal elements provided in the liquid crystal panel 21, rise and fall of some of the liquid crystal elements whose display gradation change amount is equal to or less than the average gradation change amount of the backlight light source 31. It will be performed within the extinguishing period.
  • the backlight control unit 32 shortens the lighting period of the backlight light source 31 by the extension of the extinguishing period.
  • the liquid crystal driving unit 22 sets “60” which is an index gradation corresponding to these combinations. Extracted from the gradation correspondence information T21. Then, the liquid crystal driving unit 22 supplies an applied voltage corresponding to the index gradation “60” to the liquid crystal element (see FIG. 16A), and changes the display gradation of the liquid crystal element (FIG. 16 ( b)). Then, the liquid crystal driving unit 22 supplies an applied voltage corresponding to the target gradation “64” to the liquid crystal element (see FIG. 16A). At this time, as shown in FIG.
  • the display gradation of the liquid crystal element exceeds the “64” gradation due to over-response (undershoot), and then rises to the “64” gradation and stabilizes. It becomes. Therefore, the greater the degree of overresponse of the liquid crystal element, the longer the response time until the liquid crystal element stabilizes to the target gradation, and the shorter the degree of overresponse of the liquid crystal element, the shorter the response time. Therefore, the backlight control unit 32 also determines that the liquid crystal driving unit 22 uses the gradation correspondence information T21 and the average gradation change amount is “64” for the second frame, Based on the extinction period setting information T11 (see FIG.
  • the extinction period of the backlight source 31 is set to “4.5 ms”.
  • the backlight control unit 32 determines that the liquid crystal drive unit 22 uses the gradation correspondence information T22 and the average gradation for the first frame. Based on the change amount being “128” and the extinction period setting information T11 (see FIG. 15), the extinction period of the backlight source 31 is set to “4.9 ms”.
  • the backlight control unit 32 indicates that the liquid crystal driving unit 22 uses the gradation correspondence information T22 and that the average gradation change amount is “64”. Based on the turn-off period setting information T11 (see FIG. 15), the turn-off period of the backlight source 31 is set to “4.7 ms”.
  • the backlight control unit 32 determines that the liquid crystal driving unit 22 uses the gradation correspondence information T23 and the average gradation for the first frame. Based on the change amount of “128” and the extinction period setting information T11 (see FIG. 15), the extinction period of the backlight source 31 is set to “4.5 ms”. For the second frame, the backlight control unit 32 indicates that the liquid crystal driving unit 22 uses the gradation correspondence information T22 and that the average gradation change amount is “64”. Based on the turn-off period setting information T11 (see FIG. 15), the turn-off period of the backlight light source 31 is set to “4.3 ms”.
  • the liquid crystal driving unit 22 controls the display gradation of the liquid crystal panel 21 using any of the gradation correspondence information T21 to T23.
  • the liquid crystal elements provided in 21 for some of the liquid crystal elements whose display gradation change amount is equal to or less than the average gradation change amount, the rise and fall are performed within the turn-off period of the backlight light source 31. As a result, the transition of the display gradation is not displayed. Accordingly, it is possible to improve the problem that the visibility of the liquid crystal panel 21 is lowered while suppressing the brightening of the liquid crystal element, and it is possible to suppress the motion blur of the display image on the liquid crystal panel 21.
  • the light extinction is performed with reference to the gradation change amount of the liquid crystal element having the largest luminance difference (tone change amount) between the previous and next frames in the entire image of the liquid crystal panel 21.
  • the turn-off period of the backlight light source 31 is determined using the period setting information T11, all the liquid crystal elements in the liquid crystal panel 21 can rise and fall within the turn-off period of the backlight light source 31.
  • the backlight control unit 32 may change the turn-off time in the backlight scan processing of the backlight light source 31 for each predetermined video area obtained by dividing the display area of the liquid crystal panel 21 into a plurality of vertical directions. Conceivable.
  • the average gradation change amount may be calculated for each of the six video areas, and the turn-off time may be changed according to the average gradation change amount for each of the video areas.
  • the method of controlling the voltage applied to the liquid crystal element by the liquid crystal driving unit 22 is not limited to using the gradation correspondence information T21 to T23, but for combinations before and after the change in display gradation of the liquid crystal element. It is also conceivable to control the voltage applied to the liquid crystal element by performing a predetermined calculation. Similarly, by performing a predetermined calculation on the degree of overresponse of the liquid crystal element and the amount of change in the display gradation of the liquid crystal element, the extinction period of the liquid crystal element in the backlight scanning process is calculated. Is also possible.
  • each of the LED light sources 31a of the backlight light source 31 blinks for each of the LED light source groups L1 to L12
  • all the LED light sources 31a blink simultaneously.
  • the present invention can also be applied to the intermittent lighting process.
  • the display gradation of the liquid crystal element is changed to a display gradation having a higher whiteness than the current level, or the display gradation of the liquid crystal element is changed to a display gradation having a lower whiteness level than the current level.
  • the present invention can also be applied to a configuration in which the liquid crystal element is over-responsive (overshoot or undershoot) only in either case.
  • the present invention can also be applied to a normally white system.
  • an applied voltage set to a low value so that the whiteness of the liquid crystal element is higher than a normal applied voltage is used as the overshoot voltage.
  • the liquid crystal drive unit 22 optimizes by changing a prediction parameter (described later) used when the 2-frame OS drive is performed.
  • the 2-frame OS driving is to perform OS driving (overshoot driving) of the liquid crystal element in accordance with the video gradation of the next frame and the next frame. This two-frame OS drive is performed in order to prevent the OS drive from being excessively performed due to a protruding video fluctuation of only one frame.
  • the display gradation of the current frame is “255”, the display gradation of the next frame is “0”, and the display level of the next frame is displayed.
  • the contents of 2-frame OS driving when the key is “128” will be described.
  • the display gradation changes from “0” to “128” between the next frames the index gradation becomes “130” so that overshoot occurs during the change (FIG. 12). reference).
  • the liquid crystal element when shifting from “255” of the current frame to “0” of the next frame, it does not respond sufficiently and does not change to “0”, for example, a state corresponding to “16” which is a little higher It becomes.
  • the prediction parameter is a table that defines a predicted value of the current display gradation of the liquid crystal element corresponding to each combination of the display gradation of the previous frame and the display gradation of the current frame. Then, the liquid crystal drive unit 22 adjusts the content of OS drive, that is, the degree of overresponse, based on the prediction parameter.
  • the prediction parameters may be set according to the results of experiments or simulations performed in advance.
  • the predicted value of the state of the liquid crystal element when it is changed from “255” of the current frame to “0” of the next frame is set as “16”, and at the time of transition from the next frame to the next frame.
  • the OS drive is performed not as a transition from “0” to “128” but as a transition from “16” to “128”. That is, the liquid crystal driving unit 22 performs OS driving by setting the value of the index gradation corresponding to the gradation change from the next frame to the next frame, for example, about “129” lower than “130”. As a result, the influence of a rapid fluctuation in units of frames is reduced.
  • the liquid crystal driving unit 22 can perform either or both of the prediction parameter and the OS parameter according to the presence / absence of execution of the backlight scanning process, the environmental temperature, and the like even in the two-frame OS driving. Can be considered.
  • a method for changing the prediction parameter or the OS parameter for example, it is conceivable to individually change the table values of those parameters, or to change all or part of the table to another table.
  • the moving image blur is improved equally for all the video gradations.
  • an improvement is made with an emphasis on a relatively fast moving image in which the display gradation changes abruptly for each frame.
  • the above-described intermediate improvement is achieved. Further, if a part of the prediction parameter or the OS parameter table is changed, an improvement focusing on a predetermined gradation can be performed. Of course, the same processing can be performed not only for overshoot driving when raising the display gradation but also for undershoot driving when lowering the display gradation.
  • the present invention can be applied to a liquid crystal display device such as a television receiver or a display device.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Computer Hardware Design (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Control Of Indicators Other Than Cathode Ray Tubes (AREA)
  • Liquid Crystal Display Device Control (AREA)

Abstract

L'invention porte sur un dispositif d'affichage à cristaux liquides et sur un récepteur de télévision qui sont aptes à améliorer l'aptitude de réponse d'un élément à cristaux liquides autant que possible en réponse à des conditions, dans une plage dans laquelle des réductions de lumière blanche et de visibilité peuvent être empêchées. Lorsque la gradation d'affichage de l'élément à cristaux liquides est changée, une tension appliquée est appliquée audit élément à cristaux liquides dans des cas ayant une activation de lumière intermittente d'une source de lumière de rétroéclairage, l'aptitude de réponse anormalement accrue de l'élément à cristaux liquides vers la direction de changement de la gradation d'affichage s'intensifiant avec la tension appliquée par rapport à des cas sans ladite activation de lumière intermittente. De façon plus spécifique, lorsque la gradation d'affichage de l'élément à cristaux liquides est changée en une gradation cible avec un degré plus élevé (plus bas) de blancheur que l'état actuel, une première tension appliquée prédéfinie est appliquée à l'élément à cristaux liquides dans des cas sans l'activation de lumière intermittente précédemment mentionnée, en association avec chaque combinaison avant et après des changements dans la gradation d'affichage de l'élément à cristaux liquides, et une deuxième (troisième) tension appliquée prédéfinie est appliquée à l'élément à cristaux liquides dans des cas ayant l'activation de lumière intermittente précédemment mentionnée, d'une manière telle que le degré de blancheur de l'élément à cristaux liquides devient supérieur (inférieur) à celui avec la première tension appliquée.
PCT/JP2010/064069 2009-08-21 2010-08-20 Dispositif d'affichage à cristaux liquides et récepteur de télévision WO2011021688A1 (fr)

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
JP2009-192496 2009-08-21
JP2009192496 2009-08-21
JP2009226733A JP2011075800A (ja) 2009-09-30 2009-09-30 液晶表示装置
JP2009-226733 2009-09-30
JP2010184192A JP2011065151A (ja) 2009-08-21 2010-08-19 液晶表示装置，テレビジョン受像機
JP2010-184192 2010-08-19

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Cited By (1)

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Publication number Priority date Publication date Assignee Title
US11110853B2 (en) 2017-06-07 2021-09-07 Stanley Electric Co., Ltd. Vehicle headlight system

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Publication number Priority date Publication date Assignee Title
JP2004240410A (ja) * 2003-01-15 2004-08-26 Sharp Corp 液晶表示装置
JP2005099367A (ja) * 2003-09-24 2005-04-14 Nec Lcd Technologies Ltd 液晶表示装置及び該液晶表示装置に用いられる駆動方法
WO2005101364A1 (fr) * 2004-04-13 2005-10-27 Genesis Microchip Inc. Surexcitation de pixels pour panneau lcd a pixels a temps de reponse tres lent
JP2006195170A (ja) * 2005-01-13 2006-07-27 Nec Electronics Corp コントローラ・ドライバ及びそれを用いた液晶表示装置
JP2009151277A (ja) * 2007-11-29 2009-07-09 Toshiba Mobile Display Co Ltd オーバードライブ駆動回路、表示装置用ドライバｉｃ、表示装置、及び、オーバードライブ駆動方法

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Publication number Priority date Publication date Assignee Title
JP2004240410A (ja) * 2003-01-15 2004-08-26 Sharp Corp 液晶表示装置
JP2005099367A (ja) * 2003-09-24 2005-04-14 Nec Lcd Technologies Ltd 液晶表示装置及び該液晶表示装置に用いられる駆動方法
WO2005101364A1 (fr) * 2004-04-13 2005-10-27 Genesis Microchip Inc. Surexcitation de pixels pour panneau lcd a pixels a temps de reponse tres lent
JP2006195170A (ja) * 2005-01-13 2006-07-27 Nec Electronics Corp コントローラ・ドライバ及びそれを用いた液晶表示装置
JP2009151277A (ja) * 2007-11-29 2009-07-09 Toshiba Mobile Display Co Ltd オーバードライブ駆動回路、表示装置用ドライバｉｃ、表示装置、及び、オーバードライブ駆動方法

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11110853B2 (en) 2017-06-07 2021-09-07 Stanley Electric Co., Ltd. Vehicle headlight system

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