WO2014115441A1 - Écran à cristaux liquides - Google Patents

Écran à cristaux liquides Download PDF

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Publication number
WO2014115441A1
WO2014115441A1 PCT/JP2013/083449 JP2013083449W WO2014115441A1 WO 2014115441 A1 WO2014115441 A1 WO 2014115441A1 JP 2013083449 W JP2013083449 W JP 2013083449W WO 2014115441 A1 WO2014115441 A1 WO 2014115441A1
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Prior art keywords
liquid crystal
field
signal lines
crystal panel
light
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PCT/JP2013/083449
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English (en)
Japanese (ja)
Inventor
宮田　英利
康徳 明
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シャープ株式会社
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Publication of WO2014115441A1 publication Critical patent/WO2014115441A1/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
    • G09G3/36—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
    • G09G3/3674—Details of drivers for scan electrodes
    • G09G3/3677—Details of drivers for scan electrodes suitable for active matrices only
    • 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
    • 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
    • G09G2310/0202—Addressing of scan or signal lines
    • G09G2310/0205—Simultaneous scanning of several lines in flat panels
    • 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
    • G09G2310/0235—Field-sequential colour display
    • 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
    • G09G2310/06—Details of flat display driving waveforms
    • G09G2310/061—Details of flat display driving waveforms for resetting or blanking
    • G09G2310/063—Waveforms for resetting the whole screen at once
    • 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

Definitions

  • the present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device that can see the other side of the screen.
  • one pixel transmits a red pixel provided with a color filter that transmits red light, a green pixel provided with a color filter that transmits green light, and blue light. It is divided into three sub-pixels of a blue pixel provided with a color filter. Although color display is possible by the color filters provided in these three sub-pixels, about 2/3 of the backlight light irradiated to the liquid crystal panel is absorbed by the color filter. For this reason, the color filter type liquid crystal display device has a problem of low light utilization efficiency. Therefore, a liquid crystal display device that employs field sequential driving for performing color display without using a color filter has attracted attention.
  • a display period (one frame period) of one screen is divided into three fields (first to third fields).
  • a field is also called a subframe, but in the following description, the term “field” is used in a unified manner.
  • the first field displays a red screen based on the red component of the input signal
  • the second field displays a green screen based on the green component of the input signal
  • the third field displays the input signal.
  • a blue screen is displayed based on the blue component.
  • a plurality of gate bus lines (scanning signal lines) provided in a liquid crystal panel are sequentially driven one by one. For this reason, for the pixels at the top of the panel, video data is written (charged) to the pixel capacity near the start of each field, and for the pixels at the center of the panel, video data is written (charged) to the pixel capacity. This is performed in the middle of the field, and for the pixels at the bottom of the panel, writing (charging) of video data to the pixel capacity is performed near the end of each field. Therefore, when the field sequential drive is adopted, it is necessary to emit the backlight in synchronization with the sequential scanning from the upper part of the panel to the lower part of the panel. In the following, the process of sequentially emitting the backlight from the upper part of the panel to the lower part of the panel is referred to as “backlight scanning”.
  • the color mixture means that light of different colors are unnecessarily mixed.
  • first method A conventional method in the case of performing field sequential driving using an edge light type backlight that cannot perform backlight scanning will be described. It is assumed that an LED (light emitting diode) is adopted as the backlight light source.
  • the first method as shown in FIG. 26, in one frame period, a first field for displaying a red screen, a second field for displaying a green screen, and a blue screen are displayed. And the third field.
  • the high portion of each waveform represents the “light emission state”
  • the low portion of each waveform represents the “light off state” (this is illustrated in FIGS. 1, 8 to 12, 16, 16, and FIG. 19, the same applies to FIGS. 24 to 26 and 41).
  • the red LED In the first field, the red LED (R-LED) is in a light emitting state (lighted state) throughout one field period.
  • the green LED In the second field, the green LED (G-LED) is in a light emitting state throughout one field period.
  • a blue LED B-LED is in a light emitting state throughout one field period.
  • the display image at each time point (see FIG. 26) in one frame period is as follows.
  • the display images at time point t81, time point t82, and time point t83 are images as shown in FIGS. 31, 32, and 33, respectively.
  • the display images at time t84, time t85, and time t86 are images as shown in FIGS. 34, 35, and 36, respectively.
  • the display images at time t87, time t88, and time t89 are images as shown in FIGS. 37, 38, and 39, respectively.
  • an image visually recognized by human eyes is an image in which color mixing occurs as shown in FIG.
  • the method of causing the backlight light source to emit light only in the second half period of each field by finishing the writing of the video data in each field in the first half period (hereinafter referred to as “No. 2 ”) (see FIG. 41).
  • the second method it is suppressed that the state of the previous field in each field is visually recognized by human eyes. That is, the occurrence of color mixing is suppressed.
  • Japanese Unexamined Patent Publication No. 2012-109227 discloses an invention of a display device that performs backlight scanning using a direct type backlight.
  • Japanese Laid-Open Patent Publication No. 2012-27452 discloses an invention of a liquid crystal display device that employs a method (second method described above) that causes a backlight source to emit light only in the latter half of each field.
  • the area in the panel is logically divided into three areas, and video data is written in the three areas simultaneously in parallel, thereby reducing the video data writing period in each field. Shorter than that.
  • a display image at each time point (see FIG. 41) in one frame period is as follows, for example.
  • the display images at time t91 and time t92 are images as shown in FIGS. 42 and 43, respectively.
  • the display images at time t93 and time t94 are images as shown in FIGS. 42 and 44, respectively.
  • the display images at time t95 and time t96 are images as shown in FIGS. 42 and 45, respectively.
  • an image visually recognized by human eyes is an image in which color mixing occurs at the lower part of the panel as shown in FIG.
  • Japanese Unexamined Patent Publication No. 2012-27452 it is necessary to increase the number of source bus lines in accordance with the number of divided areas in the panel. There is concern about a decrease in the rate.
  • the present invention is a liquid crystal display device capable of displaying an image while the background is in a transmissive state, and adopting a configuration in which an edge light type backlight is provided on one side of the panel, and field sequential driving without causing color mixing.
  • the purpose is to do.
  • a first aspect of the present invention is provided in correspondence with a plurality of video signal lines, a plurality of scanning signal lines, and intersections of the plurality of video signal lines and the plurality of scanning signal lines.
  • a liquid crystal panel capable of displaying an image while making a background transparent on a display unit including a plurality of pixel formation units forming a pixel matrix, and writing to a plurality of pixel capacitors included in the plurality of pixel formation units
  • a liquid crystal panel driving unit that drives the plurality of video signal lines and the plurality of scanning signal lines, a backlight provided on the back side of the liquid crystal panel, and a backlight driving unit that drives the backlight
  • a liquid crystal display device that displays a color image by dividing a frame period into a plurality of fields and displaying a screen of a different color for each field,
  • the backlight is A plurality of light sources including a light source of K color (K is an integer of 3 or more) provided near one side of the liquid crystal panel in a direction in which
  • the backlight driving unit includes the first included in the first half of each field from the start time of each field.
  • the first time point is such that the length of the period from the third time point at which writing of black display data starts in each field to the first time point in the next field is longer than the liquid crystal response time. And the third time point is set.
  • the light guide plate causes each color light source to emit light.
  • the light intensity applied to the liquid crystal panel is gradually increased as the second side portion approaches the first side portion.
  • the liquid crystal panel drive unit is configured to sequentially write video data to the plurality of pixel capacitors from the second side toward the first side, and to the plurality of pixel capacitors.
  • the plurality of video signal lines and the plurality of scanning signal lines are driven so that display data is written in all rows of the pixel matrix at the same timing.
  • N video signal lines (N is an integer of 2 or more) are provided for each column of the pixel matrix
  • the liquid crystal panel driving unit is configured to sequentially write video data to the plurality of pixel capacitors for each N rows, and to write black display data to the plurality of pixel capacitors in the pixel matrix.
  • the plurality of video signal lines and the plurality of scanning signal lines are driven so as to be performed at the same timing in all rows.
  • the light guide plate causes each color light source to emit light.
  • the light intensity applied to the liquid crystal panel is gradually increased as the second side portion approaches the first side portion.
  • the writing of video data to the plurality of pixel capacitors is sequentially performed from the second side portion toward the first side portion.
  • the light guide plate is configured so that the intensity of light given to the liquid crystal panel is uniform throughout the display unit
  • the liquid crystal panel driving unit is configured to sequentially write video data to the plurality of pixel capacitors, and to write black display data to the plurality of pixel capacitors.
  • the plurality of video signal lines and the plurality of scanning signal lines are driven so as to be sequentially performed in the same order as the writing of the video data.
  • each field constituting one frame period video data is written into all the pixel capacities only in the first half period, and in all of the latter half period, all the video data is written.
  • Data for black display is written to the pixel capacitor.
  • the light source enters a light emitting state. Therefore, each field is not affected by the display of the previous field, and color mixing is prevented.
  • the light source is provided on one side of the liquid crystal panel.
  • the transmittance decreases as the distance from the second side of the liquid crystal panel (the side where writing is performed first) approaches the first side (the side where writing is performed last).
  • the light guide plate is configured so that the intensity of light given to the liquid crystal panel gradually increases from the second side portion toward the first side portion.
  • the video data is written to the pixel capacitor in a plurality of rows. For this reason, it becomes possible to lengthen the writing period to each pixel capacitor, and the deterioration of display quality due to insufficient charging is prevented.
  • the black display data is sequentially written to the pixel capacitor in the same order as the video data is written to the pixel capacitor. For this reason, the transmittance does not differ between the upper part of the panel and the lower part of the panel. Therefore, the deterioration of display quality is suppressed, and the same effect as the first aspect of the present invention can be obtained without complicating the configuration of the light guide plate.
  • FIG. 3 is a timing chart for explaining a driving method of the liquid crystal display device according to the first embodiment of the present invention.
  • FIG. 3 is a block diagram which shows the whole function structure of a liquid crystal display device.
  • FIG. 3 is a schematic diagram illustrating a configuration example of a gate driver in the first embodiment.
  • It is a schematic perspective view of the liquid crystal display device in the said 1st Embodiment.
  • it is a figure for demonstrating arrangement
  • it is a side view of the liquid crystal display device for demonstrating the detailed structure of a backlight.
  • the said 1st Embodiment it is a figure for demonstrating the optical output from the light-guide plate to the liquid crystal panel side. It is a figure which shows the structure of 1 frame period in the said 1st Embodiment. It is a figure which shows the specific structural example of 1 field period in the said 1st Embodiment. 6 is a timing chart for explaining a relationship between a black writing period and a backlight emission period in the first embodiment. It is a figure which shows the structure of 1 frame period in the 1st modification of the said 1st Embodiment. It is a figure which shows the structure of 1 frame period in the 2nd modification of the said 1st Embodiment.
  • FIG. 28 is a diagram showing a target display image in a first field when the target image is the image shown in FIG. 27 in the conventional example (first method).
  • FIG. 28 is a diagram showing a target display image in a second field when the target image is the image shown in FIG. 27 in the conventional example (first method).
  • FIG. 28 is a diagram showing a target display image in a third field when the target image is the image shown in FIG. 27 in the conventional example (first method).
  • FIG. 28 is a diagram showing a display image at a time point t81 (see FIG. 26) in a conventional example (first method).
  • FIG. 27 is a diagram showing a display image at a time point t82 (see FIG.
  • FIG. 27 is a diagram showing a display image at a time point t83 (see FIG. 26) in the conventional example (first method).
  • FIG. 28 is a diagram showing a display image at a time point t84 (see FIG. 26) in the conventional example (first method).
  • FIG. 27 is a diagram showing a display image at a time point t85 (see FIG. 26) in the conventional example (first method).
  • FIG. 27 is a diagram showing a display image at a time point t86 (see FIG. 26) in the conventional example (first method).
  • FIG. 28 is a diagram showing a display image at a time point t87 (see FIG. 26) in the conventional example (first method).
  • FIG. 28 is a diagram showing a display image at a time point t88 (see FIG. 26) in the conventional example (first method).
  • FIG. 27 is a diagram showing a display image at a time point t89 (see FIG. 26) in the conventional example (first method). It is a figure which shows the image visually recognized by a human eye in a prior art example (1st method). It is a figure which shows the structure of 1 frame period in a prior art example (2nd method). It is a figure which shows the display image in the time t91, the time t93, and the time t95 (refer FIG. 41) in a prior art example (2nd method).
  • FIG. 44 is a diagram showing a display image at a time point t92 (see FIG.
  • FIG. 44 is a diagram showing a display image at a time point t94 (see FIG. 41) in the conventional example (second method).
  • FIG. 44 is a diagram showing a display image at a time point t96 (see FIG. 41) in the conventional example (second method). It is a figure which shows the image visually recognized by a human eye in a prior art example (2nd method).
  • FIG. 2 is a block diagram showing an overall functional configuration of the liquid crystal display device according to the first embodiment of the present invention.
  • the liquid crystal display device includes a frame rate conversion unit 100, a signal processing circuit 200, a source driver 300, a gate driver 400, an LED driver 500, a display unit 600, and a backlight 700.
  • An LED (light emitting diode) is used as the light source for the backlight 700.
  • a liquid crystal panel driving unit is realized by the source driver 300 and the gate driver 400, and a backlight driving unit is realized by the LED driver 500. It is assumed that the liquid crystal display device according to the present embodiment can operate at a driving frequency of 360 Hz.
  • the display unit 600 includes a plurality (n) of source bus lines (video signal lines) SL1 to SLn and a plurality (m) of gate bus lines (scanning signal lines) GL1 to GLm. It is installed.
  • a pixel forming portion 6 for forming pixels is provided corresponding to each intersection of the source bus lines SL1 to SLn and the gate bus lines GL1 to GLm.
  • the display unit 600 includes a plurality (n ⁇ m) of pixel forming units 6.
  • the plurality of pixel forming portions 6 are arranged in a matrix to form a pixel matrix of m rows ⁇ n columns.
  • Each pixel forming portion 6 includes a TFT 60 which is a switching element having a gate terminal connected to a gate bus line GL passing through a corresponding intersection and a source terminal connected to a source bus line SL passing through the intersection.
  • the pixel electrode 61 connected to the drain terminal of the TFT 60, the common electrode 64 and the auxiliary capacitance electrode 65 provided in common to the plurality of pixel forming portions 6, and the pixel electrode 61 and the common electrode 64 are formed.
  • a liquid crystal capacitor 62 and an auxiliary capacitor 63 formed by the pixel electrode 61 and the auxiliary capacitor electrode 65 are included.
  • the liquid crystal capacitor 62 and the auxiliary capacitor 63 constitute a pixel capacitor 66.
  • the TFT 60 for example, an oxide TFT (a thin film transistor using an oxide semiconductor for a channel layer) can be employed. More specifically, InGaZnOx (indium gallium zinc oxide) (hereinafter referred to as “IGZO”), which is an oxide semiconductor mainly containing indium (In), gallium (Ga), zinc (Zn), and oxygen (O).
  • IGZO-TFT in which a channel layer is formed by “IGZO” is a registered trademark
  • the writing speed can be increased as compared with the conventional case.
  • a transistor using an oxide semiconductor other than IGZO for the channel layer can also be employed.
  • at least one of indium, gallium, zinc, copper (Cu), silicon (Si), tin (Sn), aluminum (Al), calcium (Ca), germanium (Ge), and lead (Pb) is included. The same effect can be obtained when a transistor using an oxide semiconductor for a channel layer is employed.
  • the frame rate conversion unit 100 converts the frame rate of the input image signal DIN given from the outside.
  • a 60 Hz input image signal DIN is given to the frame rate conversion unit 100, and 360 Hz video data is output from the frame rate conversion unit 100 as target image data DAT.
  • video data is written only in the first half period (a period of one-half the length of one field) in each field constituting one frame period. That is, the drive frequency of the liquid crystal panel is 360 Hz, but the number of fields that appear in one second is 180.
  • a specific method for converting the frame rate is not particularly limited.
  • the signal processing circuit 200 receives the target image data DAT sent from the frame rate conversion unit 100, receives the digital video signal DV, the source start pulse signal SSP for controlling the operation of the source driver 300, the source clock signal SCK, and the latch A strobe signal LS, a gate start pulse signal GSP for controlling the operation of the gate driver 400, a gate clock signal GCK, and a black write control signal GBL, and an LED driver control signal S1 for controlling the operation of the LED driver 500; Is output.
  • the source driver 300 receives the digital video signal DV, the source start pulse signal SSP, the source clock signal SCK, and the latch strobe signal LS sent from the signal processing circuit 200, and applies a driving video signal to each source bus line SL. At this time, the source driver 300 sequentially holds the digital video signal DV indicating the voltage to be applied to each source bus line SL at the timing when the pulse of the source clock signal SCK is generated. The held digital video signal DV is converted into an analog voltage at the timing when the pulse of the latch strobe signal LS is generated. The converted analog voltage is applied simultaneously to all the source bus lines SL1 to SLn as drive video signals.
  • the gate driver 400 Based on the gate start pulse signal GSP and the gate clock signal GCK sent from the signal processing circuit 200, the gate driver 400 sequentially performs active scanning on the m gate bus lines GL1 to GLm during the first half of each field. Apply a signal.
  • the gate driver 400 also applies to the m gate bus lines GL1 to GLm during a part of the latter half of each field (details will be described later) based on the black write control signal GBL sent from the signal processing circuit 200. Apply active scanning signals all at once.
  • writing black display data separately from the original video data to the pixel capacity is referred to as “black writing”.
  • a voltage corresponding to black display is called “black voltage”.
  • the LED driver 500 outputs a light source control signal S2 for controlling the state of each LED constituting the backlight 700 based on the LED driver control signal S1 sent from the signal processing circuit 200.
  • a light source control signal S2 for controlling the state of each LED constituting the backlight 700 based on the LED driver control signal S1 sent from the signal processing circuit 200.
  • switching of the state of each LED is appropriately performed based on the light source control signal S2.
  • the driving video signal is applied to the source bus lines SL1 to SLn, the scanning signal is applied to the gate bus lines GL1 to GLm, and the state of each LED is appropriately switched, whereby the input image signal DIN is changed.
  • a base image is displayed on the display unit 600.
  • FIG. 3 is a schematic diagram illustrating a configuration example of the gate driver 400 in the present embodiment.
  • the gate driver 400 includes a shift register 410 including m flip-flop circuits 41 and a black writing control unit 420 for controlling black writing.
  • the black writing control unit 420 is provided with m OR circuits 42 so as to correspond one-to-one with the flip-flop circuits 41 in the shift register 410.
  • the output signal from the flip-flop circuit 41 and the black writing control signal GBL are input to the OR circuit 42.
  • the output signal from the OR circuit 42 is given to the gate bus line GL as a scanning signal.
  • the shift register 410 is configured such that the gate start pulse signal GSP is supplied to the first flip-flop circuit 41 and the gate clock signal GCK is supplied to all the flip-flop circuits 41 in common.
  • a pulse of the gate start pulse signal GSP is given to the first-stage flip-flop circuit 41 of the shift register 410.
  • the pulses included in the gate start pulse signal GSP are sequentially transferred from the first-stage flip-flop circuit 41 to the m-th stage flip-flop circuit 41.
  • the output signals from the 1st to m-th stage flip-flop circuits 41 sequentially become high level.
  • active scanning signals are sequentially applied to the m gate bus lines GL1 to GLm.
  • the black write control signal GBL is set to the high level during a part of the second half of each field. As a result, active scanning signals are applied simultaneously to the m gate bus lines GL1 to GLm.
  • FIG. 4 is a schematic perspective view of the liquid crystal display device according to the present embodiment.
  • This liquid crystal display device includes a liquid crystal panel 800 including a display unit 600 for displaying an image, and a backlight 700 for irradiating light from the back surface of the liquid crystal panel 800 (to the liquid crystal panel 800).
  • components for driving the liquid crystal panel 800 and the backlight 700 for example, a driver IC and a printed board on which the driver IC is mounted) are not shown.
  • the backlight 700 includes an LED 71 as a light source, and a light guide plate 72 for guiding light emitted from the LED 71 to the liquid crystal panel 800.
  • the backlight 700 in the present embodiment is an edge light type backlight.
  • LEDs are provided in the vicinity of one side of the liquid crystal panel and in the vicinity of the other side (the left and right sides of the liquid crystal panel) in the direction in which the gate bus line extends. (See FIG. 5).
  • LEDs are provided only in the vicinity of one side of the liquid crystal panel (the lower side of the liquid crystal panel) in the direction in which the source bus line extends (see FIG. 5). ).
  • the reason why the LEDs are provided in this way is that the frame 81 is provided only on the lower side of the liquid crystal panel 800 in the liquid crystal display device according to the present embodiment.
  • FIG. 6 is a side view of the liquid crystal display device for explaining the detailed configuration of the backlight 700 in the present embodiment.
  • the LED 71 is configured by three color LEDs including a red LED 71 (R), a green LED 71 (G), and a blue LED 71 (B).
  • the light guide plate 72 includes light diffusion particles (light diffusion beads) 73 for diffusing light emitted from the LEDs 71.
  • a plurality of light diffusing particles 73 having different refractive indexes are provided in the light guide plate 72 so that the light output from the light guide plate 72 to the liquid crystal panel 800 side becomes a curve indicated by reference numeral 77 in the graph shown in FIG. Is provided.
  • FIG. 1 is a side view of the liquid crystal display device for explaining the detailed configuration of the backlight 700 in the present embodiment.
  • the LED 71 is configured by three color LEDs including a red LED 71 (R), a green LED 71 (G), and a blue LED 71 (B).
  • the light guide plate 72 includes light
  • the vertical axis represents the intensity of light output from the light guide plate 72 to the liquid crystal panel 800 (brightness appearing on the liquid crystal panel 800), and the horizontal axis represents the relative position from the upper end of the liquid crystal panel 800. (The lower end of the liquid crystal panel 800 is 100%).
  • the light guide plate 72 is configured so that the intensity of light given to the liquid crystal panel 800 gradually increases as it approaches the lower end from the upper end of the liquid crystal panel 800 when each color LED 71 is in a light emitting state. Yes.
  • FIG. 1 is a timing chart for explaining a driving method in the present embodiment.
  • FIG. 8 is a diagram illustrating a configuration of one frame period in the present embodiment.
  • FIG. 9 is a diagram illustrating a specific configuration example of one field period in the present embodiment.
  • FIG. 10 is a timing chart for explaining the relationship between the black writing period and the backlight emission period in the present embodiment.
  • one frame period is composed of three fields (first to third fields).
  • one frame period is 16.7 milliseconds, and one field period is about 5.56 milliseconds.
  • the first field is a field in which video data for red screen is written (charged) and a red screen is displayed.
  • the second field is a field in which video data for a green screen is written and a green screen is displayed.
  • the third field is a field in which video data for a blue screen is written and a blue screen is displayed.
  • the first to third fields are repeated. Thereby, a red screen, a green screen, and a blue screen are repeatedly displayed, and a desired color display is performed.
  • the order of the first field to the third field is not particularly limited. For example, the display may be performed in the order of “blue screen, green screen, red screen”.
  • video data is written to all the pixel capacitors 66 in the display unit 600 during a period T1 until a half field period elapses from the start time of each field, that is, the first half period of each field. (Charging) is performed.
  • a period in which video data is written to all the pixel capacitors 66 is simply referred to as a “video data writing period”.
  • T1 a period in which video data is written to all the pixel capacitors 66 is simply referred to as a “video data writing period”.
  • T1 As shown in FIG. 1, m gate bus lines GL1 to GLm are sequentially driven one by one, and n video signals for driving as video data are corresponding to this.
  • source bus lines SL1 to SLn Applied to source bus lines SL1 to SLn. In this way, in this embodiment, the writing of video data for all the pixels is completed in the first half period in each field.
  • black writing period T2 In the last several milliseconds period T2 of each field, black writing is performed.
  • the period during which black writing is performed is simply referred to as “black writing period”.
  • the black writing period T2 as shown in FIG. 1, m gate bus lines GL1 to GLm are driven all at once, and in response to this, a driving video signal indicating black corresponds to n source bus lines SL1 to SL1. Applied to SLn.
  • data (black voltage) for displaying black is written in all pixels in a period slightly before the end point of each field.
  • the period until the half field period elapses from the start time of each field is the video data writing period T1, and the last several milliseconds of each field is black.
  • a period T3 from the time when a quarter field period elapses from the start time of each field to the end time of each field is a period during which the backlight is turned on (hereinafter simply referred to as “backlight emission period”). (See FIGS. 1 and 8).
  • the LED driver 500 causes the LEDs 71 of the colors corresponding to the fields to emit light.
  • the LED (light source) 71 that is to be in a light emitting state in order to display a color screen corresponding to each field is referred to as a “target LED” (target light source).
  • target LED target light source
  • the target LED in the second field is the green LED 71 (G).
  • the length of the black writing period T2 is set to 1 millisecond, for example.
  • the configuration of each field is as shown in FIG. In the following description, it is assumed that the length of the black writing period T2 is set to 1 millisecond in this way.
  • the time when a quarter field period has elapsed from the start time of each field corresponds to the first time point
  • the end time of each field corresponds to the second time point
  • the end time of each field corresponds to the third time point.
  • video data is sequentially written line by line from the upper part of the panel toward the lower part of the panel during the first half of each field. Accordingly, in each pixel, the liquid crystal starts a response from the time when the video data is written, and the transmittance reaches the target value level after a lapse of several milliseconds from the time of writing.
  • the target LED enters a light emitting state. The target LED is maintained in a light emitting state until the end of each field. As a result, a color screen corresponding to each field is displayed on the display unit 600 in the field.
  • the light guide plate 72 is configured such that the light output from the light guide plate 72 to the liquid crystal panel 800 side is a curve indicated by reference numeral 77 in the graph shown in FIG. That is, when the intensity of light output at the upper end of the panel is 100%, the intensity of light output at the lower end of the panel is 200%. In this way, the occurrence of a luminance difference between the upper part of the panel and the lower part of the panel is suppressed.
  • each field video data is written during the first half period and black writing is performed during the second half period. Further, the LED 71 is in a light emitting state from the time when a quarter field period (1.39 milliseconds) elapses from the start time of each field to the end time of the field. In this way, black writing is performed every field period, so that each field is not affected by the display of the previous field, and color mixing is prevented.
  • FIG. 10 shows changes in the waveform of the scanning signal, the on / off state of the target LED, and the transmittance of the pixel in two consecutive fields (the preceding field and the following field).
  • P1 represents a pixel on the first row
  • Pj represents a pixel on the (m / 2) th row
  • Pm represents a pixel on the mth row (final row).
  • the light guide plate 72 is configured so that the light output toward the liquid crystal panel 800 gradually increases from the upper part of the panel toward the lower part of the panel. The difference in brightness between the two is suppressed.
  • the liquid crystal response time is 2 milliseconds
  • video data is still written in the subsequent field after 2 milliseconds from the start time of the black writing period T2 of the preceding field, that is, 1 millisecond after the start time of the subsequent field.
  • the transmittance reaches the black level. If the transmittance has reached the black level, the display of the previous field is not affected, so that the target LED can be brought into a light emitting state. Therefore, the black writing period T2 and the backlight emission period T3 are set such that the length from the start time of the black writing period T2 in each field to the start time of the backlight emission period T3 in the next field is longer than the liquid crystal response time. And are set.
  • the start time of the black writing period T2 is a time one millisecond before the end time of each field, a quarter field period (1.39) from the start time of each field.
  • the target LED is turned on. Focusing on the first row, the writing of video data is started before a sufficient time has elapsed from the start of the black writing period T2. Therefore, in order to more reliably prevent the occurrence of color mixing, it is preferable to set the target LED in the light emitting state after the liquid crystal response time (here, 2 milliseconds) has elapsed from the start time of each field.
  • the target LED is in the light emitting state during the black writing period T2, but the present invention is not limited to this, and the target LED may be turned off in the black writing period T2. That is, in each field, the end point of the backlight emission period T3 may be set earlier than the start point of the black writing period T2. However, even if the target LED is made to emit light during the black writing period T2, no color mixing occurs due to this. Further, in order to increase the brightness of the screen, the backlight emission period T3 is preferably long. Therefore, in the present embodiment, the target LED is in a light emitting state even during the black writing period T2.
  • Black writing period In this embodiment, the period during which the scanning signal is on level (high level) for writing video data (one horizontal scanning period) is several microseconds, whereas the scanning signal is on for black writing.
  • the period of time (high level) (black writing period T2) is set to 1 millisecond. The reason for this will be described below.
  • the “liquid crystal step response” When writing to the pixel capacitor 66 is performed, the TFT 60 is turned on / off in each pixel formation portion 6. When the TFT 60 is turned off, the charge accumulated in the pixel electrode 61 is held. However, since the response of the liquid crystal is not completed in a very short time, the liquid crystal continues to respond by the electric field even after the TFT 60 changes from the on state to the off state.
  • the start time of the black writing period T2 is set to 1 millisecond before the end time of each field. Even so, there is a high possibility that the transmittance does not reach the black level in all the pixels.
  • the voltage is maintained even when the capacitance changes, and thus the transmittance approaches the target value (here, the black level). Therefore, if the black writing period T2 is lengthened, the transmissivity at the end of each field becomes a value closer to the black level, so that the change in capacitance after the end of the black writing period T2 becomes small.
  • the length of the black writing period T2 is set to 1 millisecond.
  • the LED 71 is provided only on the lower side of the liquid crystal panel 800 as a backlight light source. Further, no reflection wall or the like is provided in the liquid crystal panel 800. For this reason, the display part 600 can be made transparent. In each field constituting one frame period, video data is written to all the pixel capacitors 66 only in the first half period, and black writing (black display) to all the pixel capacitors 66 is performed in a part of the second half. Data is written). The LED 71 is in a light emitting state when a quarter field period has elapsed from the start of each field.
  • the LED 71 enters a light emitting state after a sufficient time has elapsed for the transmittance of the pixel to reach the black level.
  • each field is not affected by the display of the previous field, and color mixing is prevented.
  • the target display image is an image as shown in FIG. 27, the image visually recognized by the human eye is almost the image as shown in FIG.
  • a liquid crystal display device capable of displaying an image while the background is in a transmissive state
  • color mixing is performed while adopting a configuration in which an edge light type backlight is provided on one side of the panel. It is possible to perform field sequential driving without generating the above.
  • the second method (method in which writing of video data is completed in the first half period in each field and the backlight is emitted only in the second half period of each field)
  • the backlight emission period is such a short period, a light source having an extremely strong light emission power is required to perform display with sufficient luminance. It is also conceivable to extend the backlight emission period by causing the backlight to emit light when the liquid crystal responds to some extent so that the visually recognized image (image visually recognized by the human eye) is at an acceptable level.
  • the backlight emission period is expected to be about 1.39 milliseconds (the last quarter period of each field).
  • a backlight emission period T3 having a sufficient length (4.17 milliseconds) can be ensured, so that a good display quality can be obtained without reducing the color purity.
  • the length of the black writing period T2 is 1 millisecond (assuming that the liquid crystal response time is 2 milliseconds), without depending on the liquid crystal step response, By the time the next field is displayed, the transmittance at each pixel is sufficiently close to the black level. Therefore, the occurrence of color mixing is effectively suppressed.
  • one frame period is composed of three fields for displaying a red screen, a green screen, and a blue screen, respectively.
  • the present invention is not limited to this.
  • modified examples of the configuration of one frame period will be described.
  • the frame rate conversion unit 100 receives an input image signal DIN of 60 Hz, and data of 480 Hz is output from the frame rate conversion unit 100 as target image data DAT.
  • video data is written in each field constituting one frame period only in the first half period (a period of one-half length of one field). Therefore, in this modification, the driving frequency of the liquid crystal panel is 480 Hz, but the number of fields that appear in one second is 240.
  • FIG. 11 is a diagram showing a configuration of one frame period in the present modification.
  • one frame period is composed of four fields (first to fourth fields).
  • one frame period is 16.7 milliseconds and one field period is about 4.18 milliseconds.
  • the first field is a field in which red screen writing (charging) and red screen display are performed.
  • the second field is a field where green screen writing and green screen display are performed.
  • the third field is a field where blue screen writing and blue screen display are performed.
  • the fourth field is a field where white screen writing and white screen display are performed.
  • a video data writing period T1, a black writing period T2, and a backlight emission period T3 are provided as in the first embodiment.
  • the LEDs 71 of all the colors RGB are in a light emission state.
  • the liquid crystal panel 800 is irradiated with white light by causing the red LED 71 (R), the green LED 71 (G), and the blue LED 71 (B) to emit light.
  • the LEDs 71 of all these colors are displayed in the fourth field.
  • the light emission state is set.
  • FIG. 12 is a diagram showing a configuration of one frame period in the present modification.
  • one frame period is composed of three fields (first to third fields) as in the first embodiment.
  • the LEDs 71 of a plurality of colors are in a light emitting state in each field.
  • the color of the LED 71 that is in the light emission state in each field depends on the target display image.
  • the present invention can also be applied to a case where one frame period is configured by four or more fields in which the LEDs 71 of a plurality of colors are in a light emitting state.
  • the LEDs 71 of a plurality of colors are in a light emitting state in each field. For this reason, in addition to the effect similar to the said 1st Embodiment, the effect that generation
  • Second Embodiment> In the first embodiment, it is assumed that the liquid crystal display device can operate at a driving frequency of 360 Hz. However, sufficient display quality may not be obtained due to insufficient writing period. Thus, in the present embodiment, by adopting a configuration in which video data is written in three rows at a time, it is possible to write video data in all the pixel capacitors 66 only in the first half of each field. Yes. Note that the present invention can also be applied to a configuration in which video data is written every two rows or a configuration in which video data is written every four or more rows.
  • FIG. 13 is a diagram illustrating a configuration in the display unit 600 according to the present embodiment.
  • three source bus lines are provided for each column.
  • Three source bus lines indicated by symbols SLia, SLib, and SLic are provided in the i-th column, where i is an integer from 1 to n.
  • the pixel formation unit 6 in the first row is connected to the source bus line SLia
  • the pixel formation unit 6 in the second row is connected to the source bus line SLib
  • the pixel formation unit 6 in the third row is connected to the source bus line SLic.
  • the same connection relationship as in the first to third lines is repeated for every three lines.
  • FIG. 14 is a block diagram showing a schematic configuration of the gate driver 400 in the present embodiment.
  • the gate driver 400 includes a shift register 410 including (m / 3) flip-flop circuits 41 and a black writing control unit 420 for controlling black writing.
  • the black writing control unit 420 is provided with (m / 3) OR circuits 42 so as to correspond to the flip-flop circuits 41 in the shift register 410 on a one-to-one basis.
  • the output signal from the flip-flop circuit 41 and the black writing control signal GBL are input to the OR circuit 42.
  • the output signal from the OR circuit 42 is given to the gate bus line GL as a scanning signal.
  • the gate driver 400 is configured such that an output signal from one OR circuit 42 is supplied to three gate bus lines GL.
  • an output signal from the OR circuit 42 provided corresponding to the third-stage flip-flop circuit 41 is applied to the three gate bus lines GL7 to GL9.
  • the gate driver 400 configured as described above is supplied with the gate start pulse signal GSP, the gate clock signal GCK, and the black writing control signal GBL, as in the first embodiment. Accordingly, three active scan signals are sequentially applied to the m gate bus lines GL1 to GLm in the first half period of each field. Also, active scanning signals are applied simultaneously to the m gate bus lines GL1 to GLm during a part of the latter half of each field.
  • FIG. 15 is a block diagram showing a schematic configuration of the source driver 300 in the present embodiment.
  • the source driver 300 includes a shift register 310 including n flip-flop circuits 31, a sampling unit 320 including (n ⁇ 3) sampling circuits 32 for sampling the digital video signal DV based on the sampling pulse, and , And an output unit 330 that outputs a driving video signal.
  • the shift register 310 is configured such that the source start pulse signal SSP is supplied to the first-stage flip-flop circuit 31 and the source clock signal SCK is supplied to all the flip-flop circuits 31 in common.
  • the pulse of the source start pulse signal SSP is given to the first stage flip-flop circuit 31 of the shift register 310, the pulse included in the source start pulse signal SSP is changed based on the source clock signal SCK.
  • To the n-th flip-flop circuit 31 sequentially.
  • sampling pulses SAM1 to SAMn are sequentially output from the 1st to m-th stage flip-flop circuits 31.
  • the sampling unit 320 is supplied with a digital video signal DV and sampling pulses SAM1 to SAMn.
  • a digital video signal corresponding to the source bus line SLia is denoted by a symbol DVa
  • a digital video signal corresponding to the source bus line SLib is denoted by a symbol DVb
  • a digital corresponding to the source bus line SLic is represented.
  • the video signal is denoted by the symbol DVc.
  • the sampling circuit 32 the digital video signal DV is sampled based on the sampling pulse. In this embodiment, every time one sampling pulse is output from the shift register 310, the sampling unit 320 samples three digital video signals DVa, DVb, and DVc.
  • the digital video signals DV for three rows are held.
  • the held digital video signal DV is converted into an analog voltage at the timing when the pulse of the latch strobe signal LS is generated.
  • the converted analog voltage is simultaneously applied from the output unit 330 to the source bus line SL as a driving video signal.
  • FIG. 16 is a timing chart for explaining a driving method in the present embodiment.
  • m gate bus lines GL1 to GLm are sequentially driven three by three.
  • a driving video signal as video data is (n ⁇ 3) Applied to one source bus line SL.
  • video data is written by three rows in a video data writing period (a period until a half field period elapses from the start time of each field) T1.
  • the writing of the video data to all the pixel capacitors 66 in the display unit 600 is completed only in the first half period.
  • the black writing period the last several milliseconds of each field
  • data black voltage
  • the LED driver 500 causes the target LED to emit light.
  • a liquid crystal display device capable of displaying an image while the background is in a transmissive state
  • display is performed while adopting a configuration in which an edge light type backlight is provided on one side of the panel.
  • Field sequential driving can be performed without degrading quality or mixing colors.
  • N is an integer of 2 or more, and N source bus lines are provided for each column, so that video data can be written by N rows.
  • the number of source bus lines per column is increased, so that the aperture ratio of the panel is lowered. Therefore, it is preferable to reduce the number of lines to which video data is simultaneously written as much as possible without causing insufficient charging. Thereby, the fall of the aperture ratio of a panel is suppressed.
  • the video data is written in three rows from the upper side of the panel toward the lower side of the panel.
  • the panel may be logically divided into three areas, and video data may be written simultaneously in these three areas. This configuration will be described below.
  • area A the area from the 1st to kth rows is referred to as “area A”
  • area B the area from the (k + 1) to 2kth rows is referred to as “area B”
  • area C the area from the (2k + 1) th to mth lines.
  • area C the area from the 1st to kth rows.
  • FIG. 18 is a block diagram showing a schematic configuration of the gate driver 400 in this modification.
  • the first shift register 410 (1) corresponding to the area A and the first shift register 410 (1) are configured so that simultaneous video data writing can be performed in three areas (area A, area B, and area C).
  • a second shift register 410 (2) corresponding to the region B and a third shift register 410 (3) corresponding to the region C are provided in the gate driver 400.
  • the gate start pulse signal GSP is given to the flip-flop circuit 41 corresponding to the first row, the flip-flop circuit 41 corresponding to the 2k row, and the flip-flop circuit 41 corresponding to the (2k + 1) th row.
  • the flip-flop circuit 41 corresponding to the first row is included in the first shift register 410 (1), and the flip-flop circuit 41 corresponding to the 2kth row is included in the second shift register 410 (2). ) The flip-flop circuit 41 corresponding to the row is included in the third shift register 410 (3).
  • the gate bus lines GL1 to GLm are driven in the video data writing period T1, as shown in FIG. That is, in the video data writing period T1, video data is sequentially written row by row from the upper side of the panel to the lower side of the panel in the regions A and C, and from the lower side of the panel to the upper side of the panel in the region B. The video data is sequentially written row by row. The video data is written in three regions (region A, region B, and region C) simultaneously and in parallel.
  • the transmittance decreases in the region A and the region C as it approaches the panel lower side, and the transmittance decreases in the region B as it approaches the panel upper side. Therefore, in the present modification, the light guide plate 72 is configured so that the light output from the light guide plate 72 to the liquid crystal panel 800 side becomes a curve indicated by reference numeral 78 in the graph shown in FIG. Thereby, generation
  • the panel is logically divided into three areas, but the panel may be logically divided into two areas or four or more areas. Specifically, regardless of the number of divisions, the area in the display unit 600 is logically divided into a plurality of areas so that the areas defined as the first areas and the areas defined as the second areas appear alternately. be able to.
  • the light guide plate 72 may be configured as follows so that video data writing and black writing are performed as follows.
  • the intensity of light given to the liquid crystal panel 800 gradually increases as it approaches the lower end from the upper end of the liquid crystal panel 800
  • the light guide plate 72 is configured so that the intensity of light given to the liquid crystal panel 800 gradually increases as it approaches the upper end from the lower end of the liquid crystal panel 800 when each color LED 71 is in a light emitting state.
  • the writing of the video data is sequentially performed in a plurality of lines from the upper part of the panel to the lower part of the panel, and in the second area, the plurality of lines is sequentially performed from the lower part of the panel to the upper part of the panel. To be done. Black writing is performed at the same timing in all rows.
  • Third Embodiment> ⁇ 3.1 Overall configuration and backlight configuration> Since the overall configuration and the configuration of the backlight 700 are substantially the same as those in the first embodiment (see FIGS. 2 and 4 to 6), only differences from the first embodiment will be described.
  • the frame rate conversion unit 100 is supplied with an input image signal DIN of 60 Hz, and data of 540 Hz is output from the frame rate conversion unit 100 as target image data DAT.
  • the video data is written only in a period from the start of each field until a third field period elapses. Therefore, in this embodiment, the driving frequency of the liquid crystal panel is 540 Hz, but the number of fields that appear in one second is 180.
  • the black write control signal GBL provided from the signal processing circuit 200 to the gate driver 400 in the first embodiment is not necessary.
  • the light guide plate 72 in the backlight 700 is configured so that the light output to the liquid crystal panel 800 side becomes uniform as a whole (see FIG. 21).
  • FIG. 22 is a schematic diagram showing the configuration of the gate driver 400 in the present embodiment.
  • the gate driver 400 in the present embodiment is configured by a shift register 410 composed of m flip-flop circuits 41, like a gate driver having a general configuration. Further, the black driver 420 is not provided in the gate driver 400.
  • the source driver 300 can employ a known configuration.
  • the video data writing period T1 is a period from the start of each field until the one-third field period elapses.
  • a gate start pulse signal GSP having a waveform as shown in FIG. 23 is supplied to the gate driver 400 having the above-described configuration.
  • a pulse indicated by reference numeral 92 is a pulse for writing video data
  • a pulse indicated by reference numeral 93 is a pulse for black writing.
  • the gate bus lines GL1 to GLm are driven as shown in FIG.
  • ON / OFF of object LED is controlled similarly to the said 1st Embodiment.
  • the light guide plate 72 is configured so that the light output from the light guide plate 72 to the liquid crystal panel 800 side becomes uniform as a whole (see FIG. 21).
  • the video data is written only in the period from the start of each field until the one-third field period elapses, and black writing is performed in the latter half of the period. Done.
  • the target LED is in a light emitting state from the time when a predetermined period has elapsed from the start of each field to the end of the field. Note that this predetermined period is set to a time sufficient for the pixel transmittance to reach the black level.
  • black writing is performed for each field period in the liquid crystal display device that performs field sequential driving.
  • each field is not affected by the display of the previous field, and color mixing is prevented. That is, in a liquid crystal display device capable of displaying an image while the background is in a transmissive state, field sequential driving is performed without causing color mixing while adopting a configuration in which an edge light type backlight is provided on one side of the panel. Is possible.
  • black writing is sequentially performed row by row from the upper part of the panel toward the lower part of the panel, so that the transmittance does not differ between the upper part of the panel and the lower part of the panel. Therefore, the deterioration of display quality is suppressed, and the configuration of the light guide plate 72 is simplified as compared with the first embodiment.
  • video data writing and black writing are sequentially performed row by row, but the present invention is not limited to this.
  • the video data can be written in a plurality of rows, and the black data can be written in a plurality of rows.
  • N N is an integer of 2 or more
  • video signal lines are provided for each column of the pixel matrix, so that video data is sequentially written into the pixel capacitor 66 by N rows, and the pixel capacitor.
  • the liquid crystal panel driver (the gate driver 400 and the source driver 300) performs the gate writing to the gate bus line GL and the source bus so that the black writing to 66 is sequentially performed N rows in the same order as the video data writing to the pixel capacitor 66
  • the line SL can be driven.
  • the waveform of the scanning signal applied to the gate bus lines GL1 to GLm is, for example, as shown in FIG.
  • video data is written to the pixel capacitors by a plurality of rows, so that the writing period to each pixel capacitor 66 can be lengthened.
  • a plurality of video signal lines SL, a plurality of scanning signal lines GL, and a plurality of rows and a plurality of columns of pixel matrices are provided corresponding to the intersections of the plurality of video signal lines SL and the plurality of scanning signal lines GL.
  • Writing to the liquid crystal panel 800 capable of displaying an image while making the background transparent on the display unit 600 including the plurality of pixel forming units 6 and the plurality of pixel capacitors 66 included in the plurality of pixel forming units 6 is performed.
  • a liquid crystal panel driving unit (300, 400) for driving the plurality of video signal lines SL and the plurality of scanning signal lines GL, a backlight 700 provided on the back side of the liquid crystal panel 800, and the backlight And a backlight driving unit 500 for driving 700, by dividing one frame period into a plurality of fields and displaying a screen of a different color for each field.
  • the backlight 700 includes: A plurality of light sources 71 including a light source of K color (K is an integer of 3 or more) provided near one side of the liquid crystal panel 800 in a direction in which the plurality of video signal lines SL extend; A light guide plate 72 for guiding the light emitted from the plurality of light sources 71 to the liquid crystal panel 800;
  • the liquid crystal panel driving unit (300, 400) is for black display to the plurality of pixel capacitors 66 so that video data is written to the plurality of pixel capacitors 66 during the first half of each field.
  • the backlight driving unit 500 is included in the first half of each field from the start time of each field.
  • the first time point is such that the length of the period from the third time point at which writing of black display data starts in each field to the first time point in the next field is longer than the liquid crystal response time.
  • the liquid crystal display device is characterized in that the third time point is set.
  • the video data is written to all the pixel capacitors 66 only in the first half period, and in all the pixel capacitors in the second half period.
  • Data for black display is written to 66.
  • the light source 71 enters a light emitting state. Therefore, each field is not affected by the display of the previous field, and color mixing is prevented.
  • the light source 71 is provided on one side of the liquid crystal panel 800.
  • the light guide plate 72 includes the light source 71 of each color. Is configured to gradually increase the intensity of light given to the liquid crystal panel 800 as it approaches the first side from the second side when
  • the liquid crystal panel driving unit (300, 400) is configured to sequentially write video data to the plurality of pixel capacitors 66 from the second side to the first side, and Driving the plurality of video signal lines SL and the plurality of scanning signal lines GL so that writing of black display data to the pixel capacitor 66 is performed at the same timing in all the rows of the pixel matrix.
  • the liquid crystal display device according to appendix 1 which is characterized.
  • the transmittance decreases as it approaches the first side (the side where writing is performed last) from the second side (the side where writing is performed first) of the liquid crystal panel 800.
  • the light guide plate 72 is configured so that the intensity of light given to the liquid crystal panel 800 gradually increases from the second side to the first side.
  • N video signal lines SL N is an integer of 2 or more
  • the liquid crystal panel driving unit (300, 400) is configured to sequentially write video data to the plurality of pixel capacitors 66 every N rows and to display black data to the plurality of pixel capacitors 66.
  • video data is written to the pixel capacitor 66 by a plurality of rows. For this reason, it becomes possible to lengthen the writing period to each pixel capacitor 66, and the deterioration of display quality due to insufficient charging is prevented.
  • the light guide plate 72 includes the light source 71 of each color. Is configured to gradually increase the intensity of light given to the liquid crystal panel 800 as it approaches the first side from the second side when 4.
  • the region in the display unit 600 is logically divided into a plurality of regions so that regions defined as first regions and regions defined as second regions appear alternately,
  • the one side portion and the other side portion of the liquid crystal panel 800 in the extending direction of the plurality of video signal lines SL are defined as a first side portion and a second side portion, respectively, the light guide plate 72 includes the first region.
  • the intensity of light given to the liquid crystal panel 800 gradually increases as the distance from the second side approaches the first side, and the first In the two regions, when the light sources 71 of the respective colors are in a light emitting state, the intensity of light given to the liquid crystal panel 800 is gradually increased as it approaches the second side from the first side, In the first region, video data is written to the plurality of pixel capacitors 66 sequentially from the second side portion to the first side portion, and in the second region, the plurality of pixels are written. 4. The liquid crystal display device according to appendix 3, wherein video data is written to the capacitor 66 sequentially from the first side portion toward the second side portion.
  • the same effect as the configuration described in Supplementary Note 3 can be obtained by a configuration in which the region in the display unit 600 is logically divided into a plurality of regions.
  • the light guide plate 72 is configured such that the intensity of light applied to the liquid crystal panel 800 is uniform throughout the display unit 600.
  • the liquid crystal panel drive unit (300, 400) writes video data to the plurality of pixel capacitors 66 sequentially, and writes black display data to the plurality of pixel capacitors 66.
  • Appendix 1 is characterized in that the plurality of video signal lines SL and the plurality of scanning signal lines GL are driven so as to be sequentially performed in the same order as the writing of the video data to the plurality of pixel capacitors 66.
  • the black display data is sequentially written to the pixel capacitor 66 in the same order as the video data is written to the pixel capacitor 66. For this reason, the transmittance does not differ between the upper part of the panel and the lower part of the panel. Therefore, the deterioration of display quality is suppressed, and the same effect as the configuration described in Appendix 1 can be obtained without complicating the configuration of the light guide plate 72.
  • Appendix 7 The liquid crystal display device according to appendix 6, wherein the video data is written into the plurality of pixel capacitors 66 from the start of each field until a third field period elapses.
  • the light guide plate 72 is configured such that the intensity of light applied to the liquid crystal panel 800 is uniform throughout the display unit 600.
  • N video signal lines SL (N is an integer of 2 or more) are provided for each column of the pixel matrix,
  • the liquid crystal panel driving unit (300, 400) is configured to sequentially write video data to the plurality of pixel capacitors 66 every N rows and to display black data to the plurality of pixel capacitors 66.
  • the plurality of video signal lines SL and the plurality of scanning signal lines GL are driven so that the writing is sequentially performed in N rows in the same order as the writing of the video data to the plurality of pixel capacitors 66.
  • the liquid crystal display device according to appendix 1.
  • the first time point is a time point when a quarter field period has elapsed from the start time of each field,
  • the light source 71 is maintained in a light emitting state for a sufficiently long period. For this reason, the same effect as the configuration described in Supplementary Note 1 can be obtained without causing insufficient luminance.
  • the transmittance in each pixel is sufficiently close to the black level before the display in the next field is performed without depending on the step response of the liquid crystal. For this reason, the occurrence of color mixing is effectively suppressed.
  • the light source 71 is turned off during the period from the start of each field until the liquid crystal response time elapses. For this reason, the occurrence of color mixing is reliably prevented.
  • the light source 71 is turned off during a period in which black display data is written. For this reason, power consumption is reduced.
  • the K-color light source 71 is a three-color light source including a red light source 71 (R), a green light source 71 (G), and a blue light source 71 (B). Liquid crystal display device.
  • One frame period is composed of three fields including a field corresponding to a red screen, a field corresponding to a green screen, and a field corresponding to a blue screen.
  • the backlight driver is When displaying the red screen, the red light source 71 (R) is in a light emitting state, When displaying the green screen, the green light source 71 (G) is turned on, The liquid crystal display device according to appendix 13, wherein when the blue screen is displayed, the blue light source 71 (B) is in a light emitting state.
  • One frame period is composed of four fields including a field corresponding to a red screen, a field corresponding to a green screen, a field corresponding to a blue screen, and a field corresponding to a white screen.
  • the backlight driver is When displaying the red screen, the red light source 71 (R) is in a light emitting state, When displaying the green screen, the green light source 71 (G) is turned on, When displaying the blue screen, the blue light source 71 (B) is in a light emitting state, Appendix 13 is characterized in that when the white screen is displayed, the red light source 71 (R), the green light source 71 (G), and the blue light source 71 (B) are in a light emitting state.
  • one frame period is composed of three fields corresponding to the screens of the three primary colors and fields corresponding to the white screen.
  • the red light source 71 (R), the green light source 71 (G), and the blue light source 71 (B) are sequentially turned on, the light sources 71 of all the colors are turned on.
  • production of the color breakage in the case of a moving image display can be suppressed is acquired.
  • Appendix 16 The liquid crystal display device according to appendix 1, wherein the backlight driving unit 500 causes the light sources 71 of a plurality of colors to emit light in each field in order to display a screen having a color corresponding to each field. .
  • the light sources 71 of a plurality of colors are in a light emitting state in each field constituting one frame period. For this reason, in addition to the effect similar to the structure of Additional remark 1, the effect that generation
  • Each pixel forming portion 6 has a control terminal and two conduction terminals, and the control terminal is connected to the corresponding scanning signal line GL as a switching element for controlling writing to each pixel capacitor 66.
  • a thin film transistor in which a channel layer is formed of an oxide semiconductor is used as the thin film transistor 60 provided in the liquid crystal panel 800. For this reason, in addition to obtaining the effect of high definition and low power consumption, the writing speed can be increased as compared with the prior art.
  • a plurality of video signal lines SL, a plurality of scanning signal lines GL, and a plurality of rows and a plurality of columns of pixel matrices are provided corresponding to the intersections of the plurality of video signal lines SL and the plurality of scanning signal lines GL.
  • a display unit 600 including a plurality of pixel forming units 6 includes a liquid crystal panel 800 capable of displaying an image while making the background transparent, and a backlight 700 provided on the back side of the liquid crystal panel 800.
  • a method of driving a liquid crystal display device that displays a color image by dividing a period into a plurality of fields and displaying a screen of a different color for each field, A liquid crystal panel driving step of driving the plurality of video signal lines SL and the plurality of scanning signal lines GL in order to perform writing to the plurality of pixel capacitors 66 included in the plurality of pixel forming units 6; A backlight driving step of driving the backlight 700;
  • the backlight 700 includes: A plurality of light sources 71 including a light source of K color (K is an integer of 3 or more) provided near one side of the liquid crystal panel 800 in a direction in which the plurality of video signal lines SL extend; A light guide plate 72 for guiding the light emitted from the plurality of light sources 71 to the liquid crystal panel 800;
  • video data is written to the plurality of pixel capacitors 66 during the first half of each field, and black display data is written to the plurality of pixel capacitors 66.
  • the plurality of video signal lines SL and the plurality of scanning signal lines GL are driven so as to be performed in a part of the second half of each field,
  • the backlight driving step includes the first light source 71 included in the first half of each field from the start time of each field.
  • the target light source is maintained in an extinguished state during a period up to one time point, and the target light source is maintained in a light emitting state during a period from the first time point to a second time point included in the second half of each field,
  • the first time point is such that the length of the period from the third time point at which writing of black display data starts in each field to the first time point in the next field is longer than the liquid crystal response time.
  • the third time point is set.

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

Abstract

La présente invention concerne un écran à cristaux liquides qui peut afficher des images sur un fond transparent, qui utilise une architecture dans laquelle un rétroéclairage de bord est prévu sur un côté d'un panneau, et qui utilise également la couleur à séquence de champ sans provoquer de mélange des couleurs. Une ligne de bus de source et une ligne de bus de grille sont attaquées de telle sorte que des données vidéo sont écrites dans chaque capacité de pixel pendant la première moitié (T1) de chaque champ et le noir est écrit dans chaque capacité de pixel pendant la seconde moitié (T2) de chaque champ. Le rétroéclairage est fourni le long de la partie inférieure du panneau à cristaux liquides seulement. Le point (un troisième point dans le temps) auquel l'écriture du noir a commencé dans un champ d'une seule trame et le point (un premier point dans le temps) auquel le rétroéclairage est activé dans le champ suivant sont fixés de telle sorte que la longueur du temps entre ledit troisième point dans le temps et ledit premier point dans le temps est supérieure à un temps de réponse des cristaux liquides.
PCT/JP2013/083449 2013-01-24 2013-12-13 Écran à cristaux liquides WO2014115441A1 (fr)

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JP2013-011354 2013-01-24

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2016035611A1 (fr) * 2014-09-03 2016-03-10 シャープ株式会社 Dispositif d'affichage à cristaux liquides
WO2016059847A1 (fr) * 2014-10-14 2016-04-21 シャープ株式会社 Dispositif d'affichage
JP2019191291A (ja) * 2018-04-20 2019-10-31 株式会社ジャパンディスプレイ 表示装置

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004061670A (ja) * 2002-07-25 2004-02-26 Nec Corp 液晶表示装置及びその駆動方法
JP2008096927A (ja) * 2006-10-16 2008-04-24 Toshiba Matsushita Display Technology Co Ltd 液晶表示装置、液晶表示装置の駆動方法、プログラム、及び記録媒体
WO2009122716A1 (fr) * 2008-04-03 2009-10-08 パナソニック株式会社 Dispositif d'affichage d'informations

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004061670A (ja) * 2002-07-25 2004-02-26 Nec Corp 液晶表示装置及びその駆動方法
JP2008096927A (ja) * 2006-10-16 2008-04-24 Toshiba Matsushita Display Technology Co Ltd 液晶表示装置、液晶表示装置の駆動方法、プログラム、及び記録媒体
WO2009122716A1 (fr) * 2008-04-03 2009-10-08 パナソニック株式会社 Dispositif d'affichage d'informations

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2016035611A1 (fr) * 2014-09-03 2016-03-10 シャープ株式会社 Dispositif d'affichage à cristaux liquides
WO2016059847A1 (fr) * 2014-10-14 2016-04-21 シャープ株式会社 Dispositif d'affichage
JP2019191291A (ja) * 2018-04-20 2019-10-31 株式会社ジャパンディスプレイ 表示装置
JP7027238B2 (ja) 2018-04-20 2022-03-01 株式会社ジャパンディスプレイ 表示装置

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