WO2015093111A1 - Display device - Google Patents

Display device Download PDF

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Publication number
WO2015093111A1
WO2015093111A1 PCT/JP2014/073878 JP2014073878W WO2015093111A1 WO 2015093111 A1 WO2015093111 A1 WO 2015093111A1 JP 2014073878 W JP2014073878 W JP 2014073878W WO 2015093111 A1 WO2015093111 A1 WO 2015093111A1
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WIPO (PCT)
Prior art keywords
color
subframe
display
displayed
period
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Application number
PCT/JP2014/073878
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French (fr)
Japanese (ja)
Inventor
遼平 小泉
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シャープ株式会社
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Publication of WO2015093111A1 publication Critical patent/WO2015093111A1/en

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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
    • 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
    • G09G3/3413—Details of control of colour illumination sources
    • 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

Definitions

  • the present invention relates to a display device, and more particularly to a display device such as a liquid crystal display device that performs color display in a field sequential manner.
  • liquid crystal display devices that perform color display include a color filter that transmits red (R), green (G), and blue (B) light for each sub-pixel obtained by dividing one pixel into three.
  • RGB red
  • G green
  • B blue
  • the color filter type liquid crystal display device since about 2/3 of the backlight light applied to the liquid crystal panel is absorbed by the color filter, the color filter type liquid crystal display device has a problem that the light use efficiency is low. Therefore, a field sequential type liquid crystal display device that performs color display without using a color filter has attracted attention.
  • one screen display period (one frame period) is divided into three subframe periods.
  • a red image corresponding to the red component of the input signal is displayed in the first subframe period
  • a green image corresponding to the green component is displayed in the second subframe period
  • the third subframe period is displayed in the third subframe period.
  • Displays a color image on the liquid crystal panel by displaying a blue image corresponding to the blue component.
  • a field sequential type liquid crystal display device that divides one frame period into four or more subframe periods.
  • this subframe period in addition to red, green, and blue, at least one of yellow (Y), white (W), cyan (C), and magenta (M) is assigned.
  • Y yellow
  • W white
  • C cyan
  • M magenta
  • the order of assigning these colors is often determined in advance, but may be changed according to input data, for example.
  • Japanese Patent Application Laid-Open No. 2010-224065 describes a configuration of a field sequential type liquid crystal display device that appropriately changes the order of the color assignment according to the use of the device and the characteristics of a moving image. With this configuration, more preferable color selection and color sequential display are possible.
  • each color including yellow (Y) and white (W) in addition to the three primary colors is assigned to five subframe periods, or cyan (C) is further added.
  • a configuration is described in which each color is assigned to six subframe periods.
  • Japanese Patent Laid-Open No. 2003-280614 describes a configuration in which each color including yellow (Y), cyan (C), and magenta (M) in addition to the three primary colors is assigned to six subframe periods. Yes.
  • the problem when an image is displayed on a conventional field sequential type liquid crystal display device will be described.
  • the red component, the green component, and the blue component of the input signal supplied to the liquid crystal display device from the outside are 8-bit data. Therefore, the liquid crystal display device displays each color of red, green, and blue with 256 gradations.
  • FIG. 9 is a diagram illustrating the luminance of the liquid crystal panel in each subframe period when a yellow still image is displayed on a conventional field sequential type liquid crystal display device that sequentially displays red, green, and blue. .
  • the horizontal axis of the graph shown in FIG. 9 indicates time, and the vertical axis indicates the transmittance of the liquid crystal panel.
  • the second half of the first subframe period is displayed.
  • the red backlight emits light and a red component having a red gradation value of 255 is given.
  • the transmittance of the liquid crystal panel increases from 0% with time, and reaches 100% after a predetermined time. As a result, red light from the red backlight is transmitted through the liquid crystal panel, and a red image having a gradation value of 255 is displayed.
  • the transmittance of the liquid crystal panel should be 100% when the red backlight is on. Nevertheless, even if a red component having a red gradation value of 255 is given, the transmittance of the liquid crystal panel does not instantaneously become 100% from 0% in the first subframe period. Therefore, the red light from the red backlight that should pass through the liquid crystal panel during this period has insufficient luminance, and a dark red image is displayed.
  • the green backlight emits light and a green component having a green gradation value of 255 is given.
  • the transmittance of the liquid crystal panel in the first subframe period finally becomes 100%. Therefore, in the second subframe period, the transmittance of the liquid crystal panel is 100% from the beginning. Therefore, the green light from the green backlight that should pass through the liquid crystal panel does not become insufficient in luminance.
  • the viewer sees a yellowish-green image with a green color instead of a yellow image in which red and green are correctly mixed.
  • Such a yellow color in which green is greatly mixed is a color having a hue different from that of yellow that should be originally displayed.
  • the blue backlight emits light and a blue component having a blue gradation value of 0 is given.
  • the transmittance of the liquid crystal panel is originally 0%, and the light of the blue backlight is blocked by the liquid crystal panel, and the blue image should not be displayed.
  • the transmittance of the liquid crystal panel does not instantaneously become 0% from 100% in the second subframe period.
  • the transmittance of the liquid crystal panel in the third subframe period is affected by the transmittance in the second subframe period, it takes time until the transmittance of the liquid crystal panel becomes 0%. .
  • part of the blue light from the blue backlight to be blocked by the liquid crystal panel is transmitted, and a blue image is displayed. As a result, the viewer sees an image in which blue is mixed, and color reproducibility deteriorates.
  • an object of the present invention is to provide a field sequential display device in which the occurrence of color breakup and flicker is prevented by fixing the color order and the decrease in color reproducibility is suppressed.
  • a first aspect of the present invention is a display device that divides one frame period into a plurality of subframe periods and displays images of different colors for each subframe period,
  • a display panel including a plurality of pixel formation portions arranged in a matrix;
  • a display control circuit that outputs a corrected video signal for controlling the light transmittance of the plurality of pixel forming units for each subframe period based on an input signal;
  • a drive circuit that drives the plurality of pixel forming units based on the corrected video signal,
  • the display control circuit displays a yellow image on the display panel in one of the subframe periods, and displays white on the display panel in a subframe period immediately after the subframe period in which the yellow image is displayed.
  • the corrected video signal in which the different color is assigned to the plurality of subframe periods is output so that a blue image is displayed.
  • the display control circuit assigns red, green, and blue to the plurality of subframe periods in a predetermined order.
  • the display control circuit assigns red, green, and blue to three consecutive subframe periods when a white image is displayed in the immediately following subframe period.
  • the display control circuit assigns green and red to two consecutive subframe periods in that order.
  • the display control circuit assigns at least one of cyan and magenta colors to the plurality of subframe periods.
  • a sixth aspect of the present invention is the fifth aspect of the present invention,
  • the display control circuit includes: When assigning cyan, assign cyan and red in that order to two consecutive subframe periods, When magenta color is assigned, magenta color and green color are assigned in order to two consecutive subframe periods.
  • the pixel formation unit may include a liquid crystal element whose light transmittance is controlled.
  • one frame period is divided into a plurality of subframe periods on a display panel including a plurality of pixel formation portions arranged in a matrix, and images of different colors are displayed for each subframe period.
  • Display method A display control step of outputting a corrected video signal for controlling the light transmittance of the plurality of pixel forming units for each subframe period based on an input signal; A driving step of driving the plurality of pixel forming units based on the corrected video signal, In the display control step, a yellow image is displayed on the display panel in one of the subframe periods, and a white color is displayed on the display panel in a subframe period immediately after the subframe period in which the yellow image is displayed.
  • the corrected video signal in which the different color is assigned to the plurality of subframe periods is output so that a blue image is displayed.
  • each color is assigned to a plurality of subframe periods so that white or blue is displayed in a subframe period immediately after the subframe period in which yellow is displayed.
  • the display quality of the apparatus can be improved.
  • a display device using known three primary colors can be used by assigning red, green, and blue to a plurality of subframe periods in a predetermined order.
  • the third aspect of the present invention it is possible to perform display with good color reproducibility by assigning red, green, and blue to three consecutive subframe periods.
  • the color reproducibility can be improved by assigning the green color having the higher luminous efficiency before the red color having the lower luminous efficiency.
  • a display device using a known additional color in addition to the known three primary colors is used by assigning at least one of cyan and magenta colors to a plurality of subframe periods. Color expression can be improved.
  • a display device using a known additional color can perform display with good color expression and further improve color reproducibility. it can.
  • a general liquid crystal display device can be used.
  • FIG. 1 is a block diagram illustrating a configuration of a field sequential type liquid crystal display device according to a first embodiment of the present invention.
  • FIG. In the said embodiment it is a figure which shows the display color of each sub-frame period, and its lighting period. It is a figure which shows the brightness
  • FIG. 1 is a block diagram showing a configuration of a field sequential type liquid crystal display device 10 according to the first embodiment of the present invention.
  • the liquid crystal display device 10 shown in FIG. 1 performs color display by a field sequential color system that divides one frame period into five subframe periods.
  • the liquid crystal display device 10 includes a liquid crystal panel 11, a timing control circuit 12, a backlight control circuit 13, a display control circuit 16, a scanning signal line drive circuit 17, a video signal line drive circuit 18, and a backlight unit 20. And a switch group 21 and a power supply circuit 22.
  • one frame period is 1/60 seconds and each subframe period is 1/300 seconds.
  • the length is not particularly limited as long as it is a known display period.
  • the red component (red tone value), green component (green tone value), and blue component (blue tone value) of the input signal input to the liquid crystal display device 10 from the outside are each 8 bits. It is assumed to be data.
  • the liquid crystal panel 11 includes a plurality (m) of video signal lines S1 to Sm, a plurality (n) of scanning signal lines G1 to Gn, a plurality of video signal lines S1 to Sm and a plurality of video signal lines.
  • a plurality (m ⁇ n) of pixel forming portions 30 provided corresponding to the intersections with the scanning signal lines G1 to Gn are included.
  • Each pixel forming portion 30 includes a TFT 31 that functions as a switching element, a pixel electrode 32 connected to the drain terminal of the TFT 31, and a common electrode 33 that forms a liquid crystal capacitance together with the pixel electrode 32.
  • the gate terminal of the TFT 31 is connected to the scanning signal line Gi (1 ⁇ i ⁇ n), and the source terminal is connected to the video signal line Sj (1 ⁇ j ⁇ m).
  • the input signal DV is input to the timing control circuit 12 and the display control circuit 16 from the outside.
  • the timing control circuit 12 is configured to emit red, green, and blue LEDs (Light Emitting Diodes) 20r, 20g, and 20b included in the backlight unit 20, and the video signal line driving circuit 18 is configured to perform red, green, and blue.
  • the control signals C1 and C2 are generated based on the input signal DV so that the timings for outputting the driving image signals to the video signal lines S1 to Sm coincide with each other.
  • the timing control circuit 12 gives the control signal C1 to the display control circuit 16 and gives the control signal C2 to the backlight control circuit 13.
  • the display control circuit 16 adds the gradation values of yellow (Y) and white (W) based on the input signal DV representing the gradation values of red (R), green (G), and blue (B), and A corrected video signal CV representing the gradation values of a total of five kinds of corrected red, green, and blue gradation values is output.
  • a method for calculating the display gradation value of a certain pixel composed of five display colors (RGBYW) from the input gradation value of a certain pixel composed of three primary colors (RGB) is well known. For example, the three primary colors From a certain gradation value composed of (RGB), gradation values composed of five display colors (RGBYW) are generated based on a predetermined color distribution algorithm.
  • This color allocation algorithm may be any known algorithm. For example, a predetermined amount of an achromatic color component, that is, white (W) is extracted in consideration of the color balance and gamma characteristics of each color over the entire screen, and based on each gradation value (RGB) from which the achromatic color component is removed, The gradation values composed of the remaining four display colors (RGBY) are determined so that the distribution ratio is uniform. Each gradation value determined in this way is supplied to the video signal line drive circuit 18 as a corrected video signal CV.
  • the display control circuit 16 controls the scanning signal line driving circuit 17 (for example, a gate clock signal) C3 based on the control signal C1 given from the timing control circuit 12 and the input signal DV inputted from the outside. And a control signal (for example, a source clock signal) C4 for the video signal line driving circuit 18 is generated.
  • the display control circuit 16 gives the control signal C4 to the video signal line drive circuit 18 and gives the control signal C3 to the scanning signal line drive circuit 17.
  • the scanning signal line driving circuit 17 sequentially outputs active scanning signals to the scanning signal lines G1 to Gn based on the control signal C3.
  • the video signal line drive circuit 18 generates a drive image signal based on the corrected video signal CV, and outputs the drive image signal to each of the video signal lines S1 to Sm at a timing determined by the control signal C4.
  • the driving image signals output to the video signal lines S1 to Sm are given to the pixel capacitors via the TFTs 31 connected to the active scanning signal lines G1 to Gn. Accordingly, a voltage corresponding to the driving image signal is applied to the liquid crystal, and the transmittance of the liquid crystal changes according to the applied voltage, so that an image is displayed on the liquid crystal panel 11.
  • the scanning signal line driving circuit 17 and the video signal line driving circuit 18 together may be simply referred to as a driving circuit below.
  • the backlight unit 20 includes a two-dimensionally arranged red LED (Light Emitting Diode) 20r, a green LED 20g, and a blue LED 20b.
  • the red LED 20r, the green LED 20g, and the blue LED 20b are each independently connected to the power supply circuit 22 via the switch group 21.
  • the backlight control circuit 13 is a backlight control signal for appropriately turning on (turning on) each switch included in the switch group 21 for each subframe period based on the control signal C2 provided from the timing control circuit 12. BC is generated and the backlight control signal BC is supplied to the switch group 21.
  • the switch group 21 applies a power supply voltage by connecting one or more of the red LED 20r, the green LED 20g, and the blue LED 20b to the power supply circuit 22 at an appropriate timing based on the backlight control signal BC. Accordingly, one or more of the red LED 20r, the green LED 20g, and the blue LED 20b emit light as described later in accordance with the timing at which the driving image signal is applied to the video signal lines S1 to Sm, and the liquid crystal is displayed every subframe period.
  • One or more of red, green, and blue light is emitted from the back of the panel 11. For example, when red and green light is irradiated, yellow is displayed when mixed, and when red, green, and blue light is irradiated, white is displayed when mixed. Become a color.
  • a yellow LED may be newly provided to display the yellow color, or a white LED may be newly provided to display the white color.
  • a known light source such as red, green, and blue CCFL (Cold Cathode Fluorescent Lamp) may be used instead of the red, green, and blue LEDs 20r, 20g, and 20b.
  • the liquid crystal display device 10 divides one frame period into first to fifth subframe periods, and displays the display colors assigned to the subframe periods in the order shown in FIG. Hereinafter, display in each subframe period will be described with reference to FIGS.
  • FIG. 2 is a diagram showing display colors and their lighting periods in each subframe period. As shown in FIG. 2, one frame period is divided into five subframe periods from first to fifth. The first half of each subframe period is a non-lighting period and the second half is a lighting period. is there. The reason why the first half is in the non-lighting period is to prevent color reproducibility from deteriorating due to color mixing with the display color in the previous frame. Note that the non-lighting period in FIG. 2 is a 1 ⁇ 2 frame period, but the length thereof is not particularly limited and may be omitted.
  • a voltage corresponding to the driving image signal is applied to the pixel capacitance of each pixel formation unit.
  • all the pixel capacitances are applied in a very short time. Shall be charged.
  • the display color assigned to the first subframe period is red (R)
  • the display color assigned to the second subframe period is green (G)
  • the third subframe is blue (B)
  • the display order determined in advance in one frame period is not changed at least during the display operation of the apparatus. This is because, when the order is changed, color breakage and flicker may occur, and the display quality deteriorates. However, even if it is changed, the effect described later can be obtained, so that the order can be appropriately changed.
  • these three primary colors may be displayed in a predetermined order in the first to third subframe periods (or the third to fifth subframe periods as will be described later), and the order shown in FIG. It is not limited to.
  • the display color assigned to the fourth subframe period is yellow (Y), and the display color assigned to the fifth subframe period is white (W).
  • the display order in which white is displayed immediately after displaying yellow is one of the configurations unique to the present invention. Therefore, unlike the case of the three primary colors described above, this order must be fixed. This characteristic configuration improves yellow color reproducibility and improves display quality as will be described later. Another specific configuration will be described later.
  • any of red, blue, and green may be displayed before yellow is displayed, or a configuration in which yellow is displayed in the first subframe period may be employed.
  • any of red, blue, and green may be displayed after displaying white.
  • red, blue, and green are preferably displayed within three consecutive subframe periods because color reproducibility is improved and display quality is improved. Therefore, it is preferable that the three primary colors are displayed in a predetermined order in any one of the continuous subframe periods from the first to the third or the third to the fifth.
  • this order is preferably red, blue and green. That is, in order to improve color reproducibility, it seems that the order of green, red, and blue is most preferable in the order of high luminous efficiency, as will be described later.
  • each pixel forming unit 30 is driven based on the gradation value indicating the red color of the corrected video signal CV converted by the display control circuit 16, and in the second half thereof.
  • the red LED 20r emits light.
  • each pixel forming unit 30 is driven based on the gradation value indicating green of the corrected video signal CV, and the green LED 20g emits light in the latter half.
  • each pixel forming unit 30 is driven based on the gradation value indicating blue of the corrected video signal CV, and the blue LED 20b emits light in the latter half.
  • each pixel forming unit 30 is driven based on the gradation value indicating yellow of the corrected video signal CV, and in the latter half, the red LED 20r and the green LED 20g emit light. In addition, it may replace with the structure which red LED 20r and green LED 20g light-emit, and the structure which yellow LED newly provided light-emits may be sufficient.
  • each pixel forming unit 30 is driven based on the gradation value indicating white of the corrected video signal CV, and in the latter half, the red LED 20r, the green LED 20g, and the blue LED 20b. Emits light. In addition, it may replace with the structure which these LED light-emits, and the structure from which white LED newly provided light-emits may be sufficient.
  • the screen of the liquid crystal panel 11 displays each color one after another with the brightness corresponding to the corresponding gradation value in each subframe period. A color image can be displayed.
  • display of the liquid crystal panel in the fourth and fifth subframe periods which is a characteristic configuration of the present embodiment, will be described.
  • FIG. 3 is a diagram showing the luminance of the liquid crystal panel during the fourth and fifth subframe periods when a yellow still image is displayed on the liquid crystal display device of the present embodiment.
  • the horizontal axis indicates time and the vertical axis indicates the transmittance of the liquid crystal panel, as in FIG.
  • a yellow image is displayed as an image in which the transmittance of the liquid crystal panel changes greatly between adjacent subframe periods, and for convenience of explanation, the yellow gradation value is 255 and the white color is white.
  • An image having a gradation value of 0 is displayed.
  • the yellow gradation value is smaller than 255 due to the relationship between the display gradations of red, green, and blue assigned to the first to third subframe periods, and the white gradation value is Generally it is greater than zero.
  • the transmittance of the liquid crystal panel is shown to change from the start of each subframe period. In practice, however, a predetermined time is required to hold the charge in the pixel capacitance in each pixel formation portion. is necessary.
  • the red LED 20r and the green LED 20g emit light, and a driving image signal having a yellow gradation value of 255 is input to each pixel formation unit. Is done.
  • the transmittance of the liquid crystal panel increases from 0% with time, and reaches 100% after a predetermined time.
  • yellow light in which light from the red LED 20r and green LED 20g is mixed is transmitted through the liquid crystal panel, and a yellow image having a gradation value of 255 is displayed.
  • the transmittance of the liquid crystal panel should be 100% during the lighting of the red LED 20r and the green LED 20g. Nevertheless, even when a driving image signal having a yellow gradation value of 255 is input, the transmittance of the liquid crystal panel is 0% (here, the transmittance of the liquid crystal panel in the previous subframe period). There is no instant 100%. Accordingly, the yellow mixed color light to be transmitted through the liquid crystal panel during this period is insufficient in luminance, and a slightly dark yellow image is displayed.
  • the red LED 20r, the green LED 20g, and the blue LED 20b emit light, and a driving image signal with a white gradation value of 0 is input to each pixel formation unit.
  • the transmittance of the liquid crystal panel is originally 0%, and the light (mixed color) from the backlight is blocked by the liquid crystal panel, and a white image should not be displayed.
  • the transmittance of the liquid crystal panel does not instantaneously become 0% from 100% in the fourth subframe period.
  • the transmittance of the liquid crystal panel in the fifth subframe period is affected by the transmittance in the fourth subframe period, it takes time until the transmittance of the liquid crystal panel becomes 0%. . During this time, a part of the white mixed light from the backlight to be blocked by the liquid crystal panel is transmitted, and a white image is displayed. As a result, the viewer sees a yellow image in which white is mixed.
  • white is an achromatic color
  • the color balance is not greatly lost due to color mixing. If the brightness of the white color is small, the color balance collapse due to the mixed color becomes smaller. Therefore, the yellow image is displayed without greatly losing the color balance. This improves the color reproducibility of the device and improves the display quality.
  • the liquid crystal display device 10 prevents the occurrence of color breakup and flicker by fixing the allocation order (color order) of the five display colors (RGBYW) to each subframe period.
  • the allocation order color order of the five display colors (RGBYW)
  • RGBYW five display colors
  • FIG. 4 is a graph showing the relationship between luminous efficiency and light wavelength.
  • the visibility (in a bright place) is maximized with respect to (yellowish green) light having a wavelength of 555 nm. Therefore, the visibility to yellow light having a wavelength of around 580 nm is higher than that of light of other colors, and when this yellow color balance is lost, the collapse is more noticeable than other colors. .
  • the color reproducibility of the entire apparatus is lowered and the display quality is lowered.
  • the yellow image is displayed without greatly losing the color balance, so that the reduction in the color reproducibility of the apparatus is suppressed and the display quality is improved.
  • Second Embodiment> ⁇ 2.1 Configuration of liquid crystal display device>
  • the entire configuration of the field sequential type liquid crystal display device according to the second embodiment of the present invention is the same as that of the first embodiment (see FIG. 1), and one frame period is divided into six subframe periods. Since the same operation is performed except for the division, the description thereof is omitted.
  • the liquid crystal display device in this embodiment is partially different in operation of the display control circuit 16 from the first embodiment in that it uses six subframe periods. That is, the display control circuit 16 performs cyan (C), yellow (Y), and white (W) based on the input signal DV representing the gradation values of red (R), green (G), and blue (B). ), And the corrected video signal CV representing the gradation values of a total of six colors including the corrected red, green, and blue gradation values is output.
  • a method for calculating display gradation values of a certain pixel composed of six display colors (RGBCYW) from input gradation values of a certain pixel composed of three primary colors (RGB) is the same as in the first embodiment. The description is omitted because it is well known.
  • the liquid crystal display device 10 divides one frame period into first to sixth subframe periods, and displays display colors assigned to the subframe periods in the order shown in FIG. Hereinafter, display in each subframe period will be described with reference to FIG.
  • FIG. 5 is a diagram showing display colors and their lighting periods in each subframe period of the present embodiment. As shown in FIG. 5, one frame period is divided into six subframe periods from first to sixth. The first half of each subframe period is a non-lighting period, and the latter half is a lighting period. is there. This is the same as the case shown in FIG.
  • the display color assigned to the second subframe period is red (R) in the same order as the first embodiment, and the display color assigned to the third subframe period is green. (G), and the display color assigned to the fourth subframe period is blue (B).
  • the display order is preferably not changed at least during the display operation of the apparatus as described above, but can be changed as appropriate. These three primary colors may be displayed in a predetermined order in the second to fourth subframe periods (or other consecutive subframe periods), and are not limited to the order shown in FIG.
  • the display color assigned to the fifth subframe period is yellow (Y), and the display color assigned to the sixth subframe period is white (W).
  • the display order in which white is displayed immediately after displaying yellow is one of the configurations unique to the present invention. This is the same as in the first embodiment, and this order must be fixed as well. With this characteristic configuration, yellow color reproducibility can be improved and display quality can be improved as in the first embodiment.
  • any of red, blue, green, and cyan may be displayed, or yellow may be displayed in the first subframe period.
  • any of red, blue, green, and cyan may be displayed after displaying white.
  • red, blue, and green are preferably displayed within three consecutive subframe periods because color reproducibility is improved and display quality is improved. Further, as described above, it is preferable that the order is the order of red, blue, and green. The reason why red is assigned in the second subframe period will be described in detail later.
  • each pixel forming unit 30 is driven based on the gradation value indicating the cyan color of the corrected video signal CV, and in the latter half, the green LED 20g and the blue LED 20b emit light.
  • the green LED 20g and the blue LED 20b emit light
  • a configuration in which a newly provided cyan LED emits light may be used.
  • cyan can be assigned as appropriate, but as shown in FIG. 5, it is extremely preferable to assign red after cyan as the color reproducibility becomes higher. That is, since cyan (C) is expressed by a mixed color of green (G) and blue (B), when red (R) is displayed in the immediately following subframe period, two consecutive subframe periods are displayed. As long as attention is focused on, white is expressed by a mixture of the three primary colors.
  • the transmittance of the liquid crystal panel is instantaneously changed from 100% to 0% in the second subframe period.
  • a part of the red mixed color light from the backlight to be blocked by the liquid crystal panel is transmitted until the transmittance of the liquid crystal panel reaches the original 0%.
  • an image including white is displayed within the continuous period.
  • the viewer sees a cyan image in which white is mixed.
  • white is an achromatic color
  • the color balance is not greatly lost due to color mixing. If the brightness of the white color is small, the color balance collapse due to the mixed color becomes smaller. Therefore, the cyan image is displayed without greatly losing the color balance. This improves the color reproducibility of the device and improves the display quality.
  • the fifth and sixth subframe periods are the same as those in the fourth and fifth subframe periods in the first embodiment, the description thereof is omitted.
  • the cyan color is described as an example, but a magenta color (M) may be used instead.
  • M magenta color
  • FIG. 6 is a diagram showing another example of the display color and its lighting period in each subframe period of the present embodiment. As shown in FIG. 6, as in FIG. 5, one frame period is divided into six subframe periods from 1st to 6th, but magenta is used instead of cyan, and its allocation The position is also different.
  • each pixel forming unit 30 is driven based on the gradation value indicating the magenta color of the corrected video signal CV, and the red LED 20r and the blue LED 20b emit light in the latter half.
  • a newly provided magenta LED may emit light.
  • magenta color assignment can be performed as appropriate, but as shown in FIG. 6, it is extremely preferable to assign green color after magenta color because the color reproducibility becomes higher. That is, since the magenta color (M) is expressed by a mixed color of red (R) and blue (B), when green (G) is displayed in the immediately following subframe period, two consecutive subframe periods As long as attention is focused on, white is expressed by a mixture of the three primary colors.
  • blue is assigned in the fourth subframe period in order to improve the color reproducibility of cyan with higher luminous efficiency. Therefore, red is assigned in the first subframe period.
  • the display color assigned to the fifth subframe period is yellow (Y), and the display color assigned to the sixth subframe period is white (W). Thus, yellow is displayed.
  • a display order in which white is displayed immediately after is one of the configurations unique to the present invention. This is the same as in the first embodiment, and this order must be fixed as well.
  • the liquid crystal display device 10 is arranged in the order (colors) of allocation of the six display colors (CRGBYW or RMGBYW) to each subframe period for the same reason as described in the first embodiment.
  • the (order) By fixing the (order), it is possible to prevent the occurrence of color breakup and flicker, and by assigning white to the subframe period immediately after the subframe period to which yellow is assigned, it is possible to suppress a decrease in color reproducibility.
  • the number of display colors is increased (by adding either cyan or magenta color) as compared with the first embodiment, color expression can be improved.
  • This color reproducibility is also called color reproducibility.
  • Wide color reproducibility by multicolor display is referred to here as color reproducibility, and faithful reproducibility of colors with suppressed deviation from the original color to be displayed. Is referred to herein as color reproducibility.
  • cyan color it is assigned to two consecutive subframe periods in the order of cyan and red
  • magenta color it is assigned to two consecutive subframe periods in the order of magenta and green. If assigned, the color reproducibility of cyan or magenta can be further improved.
  • the liquid crystal display device in this embodiment is partially different in operation of the display control circuit 16 from the first embodiment in that it uses seven subframe periods. That is, the display control circuit 16 performs cyan (C), magenta (M), and yellow (Y) based on the input signal DV representing the gradation values of red (R), green (G), and blue (B). ) And white (W) gradation values are added, and a corrected video signal CV representing gradation values of a total of seven types of corrected red, green, and blue gradation values is output.
  • the liquid crystal display device 10 divides one frame period into first to seventh subframe periods, and displays the display colors assigned to the subframe periods in the order shown in FIG. Hereinafter, display in each subframe period will be described with reference to FIG.
  • FIG. 7 is a diagram showing display colors and their lighting periods in each subframe period of the present embodiment. As shown in FIG. 7, one frame period is divided into seven subframe periods from first to seventh, and the first half of each subframe period is a non-lighting period and the second half is a lighting period. is there. This is the same as the case shown in FIG.
  • the present embodiment is configured to assign both the cyan color and the magenta color, which are alternatively assigned in the second embodiment. That is, the display color assigned to the first subframe period is cyan (C), and the display color assigned to the second subframe period is red (R). Further, the display color assigned to the third subframe period is magenta (M), and the display color assigned to the fourth subframe period is green (G). Although it is possible to interchange the first and second subframe periods and the third and fourth subframe periods, from the viewpoint of emphasizing color reproducibility of cyan with high luminous efficiency, It is preferable to assign in the order shown in this embodiment.
  • the display color assigned to the sixth subframe period is yellow (Y), and the display color assigned to the seventh subframe period is white (W).
  • the display order in which white is displayed immediately after displaying yellow is one of the configurations unique to the present invention. This is the same as in the first embodiment, and this order must be fixed as well. With this characteristic configuration, yellow color reproducibility can be improved and display quality can be improved as in the first embodiment.
  • any of red, blue, green, magenta, and cyan may be displayed, or yellow may be displayed in the first subframe period. . Further, after displaying white, any of red, blue, green, magenta, and cyan may be displayed.
  • the liquid crystal display device 10 assigns seven display colors (CRMGBBYW) to each subframe period (color order) for the same reason as described in the first embodiment.
  • CRMGBBYW display colors
  • white color is assigned to the subframe period immediately after the subframe period to which yellow is assigned, and the deterioration of color reproducibility can be suppressed.
  • the number of display colors is increased (by using both cyan and magenta colors) as compared with the second embodiment, color reproducibility can be further improved.
  • the liquid crystal display device 10 divides one frame period into first to fifth subframe periods, and displays the display colors assigned to the subframe periods in the order shown in FIG. Hereinafter, display in each subframe period will be described with reference to FIG.
  • FIG. 8 is a diagram showing display colors and their lighting periods in each subframe period of the present embodiment. As shown in FIG. 8, one frame period is divided into five subframe periods from first to fifth. The first half of each subframe period is a non-lighting period and the second half is a lighting period. is there. This is the same as the case shown in FIG.
  • the display color assigned to the fourth subframe period is the same as that of the first embodiment in that it is yellow (Y), but the display color assigned to the fifth subframe period is the same.
  • Is blue (B) the display order of displaying blue immediately after displaying yellow in this way is one of the structures unique to the present invention. Although this point is completely different from the first embodiment, this order must be fixed as in the case of the first embodiment. With this characteristic configuration, yellow color reproducibility can be improved and display quality can be improved as in the first embodiment.
  • the color reproducibility becomes higher when the red color is assigned after the cyan color shown in FIG. 5 and the color reproducibility becomes higher when the blue color is assigned after the yellow color shown in FIG. That is, since yellow (Y) is expressed by a mixed color of red (R) and green (G), when blue (B) is displayed in the immediately following subframe period, two consecutive subframe periods are displayed. As long as attention is paid, white is expressed by a mixture of the three primary colors.
  • the transmittance of the liquid crystal panel is instantaneously changed from 100% to 0% in the second subframe period. No part of the blue mixed color light from the backlight to be blocked by the liquid crystal panel is transmitted until the transmittance of the liquid crystal panel reaches 0%.
  • an image including white is displayed within the continuous period.
  • white is an achromatic color
  • the color balance is not greatly lost due to color mixing. If the brightness of the white color is small, the color balance collapse due to the mixed color becomes smaller. Therefore, the yellow image is displayed without greatly losing the color balance.
  • the color reproducibility of the apparatus particularly the yellow color reproducibility with high luminous efficiency, is improved, and the display quality is improved.
  • the display color assigned to the first subframe period is white (W), but the order of assignment is not limited.
  • W white
  • the last subframe period in a certain frame period is continuous with the first subframe period in the next frame period, in the configuration of the present embodiment in which blue is assigned to the fifth subframe period, It is not preferable to assign red or green to each subframe period. Therefore, color reproducibility can be improved by assigning white as in this embodiment.
  • the color reproducibility can be improved by the characteristic configuration in which blue is assigned to the subframe period immediately after the subframe period to which yellow is assigned.
  • blue any of red, blue, green, magenta, and cyan may be displayed before yellow is displayed, and yellow is displayed in the first subframe period. It may be. Further, after displaying blue, any of red, green, white, magenta, and cyan may be displayed.
  • the liquid crystal display device has been described as an example.
  • the liquid crystal is not necessarily used, and a known shutter element that replaces the liquid crystal is used. There may be.
  • the gradation in one subframe period has a response characteristic that affects the gradation in the next subframe period. is there.
  • the present invention is applied to a color display device, and is particularly suitable for a display device such as a liquid crystal display device that performs color display by a field sequential method.

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Abstract

When one frame period in a field sequential type liquid crystal display device is divided into five subframe periods, red (R), green (G), and blue (B) are displayed in first through third subframe periods, yellow (Y) is displayed in a fourth subframe period, with white (W) being displayed in a fifth subframe period directly thereafter. By displaying the achromatic color white directly after yellow, which is a color in which color balance being off tends to be more noticeable, lowering of color reproducibility is suppressed.

Description

表示装置Display device
　本発明は、表示装置に関し、より詳しくは、フィールドシーケンシャル方式でカラー表示を行なう液晶表示装置などの表示装置に関する。 The present invention relates to a display device, and more particularly to a display device such as a liquid crystal display device that performs color display in a field sequential manner.
　カラー表示を行う液晶表示装置の多くは、１つの画素を３分割したサブ画素ごとに、赤色（Ｒ）、緑色（Ｇ）、および青色（Ｂ）の光を透過させるカラーフィルタを備えている。しかし、液晶パネルに照射されるバックライト光の約２／３がカラーフィルタで吸収されるために、カラーフィルタ方式の液晶表示装置は光利用効率が低いという問題を有する。そこで、カラーフィルタを用いずにカラー表示を行うフィールドシーケンシャル方式の液晶表示装置が注目されている。 Many liquid crystal display devices that perform color display include a color filter that transmits red (R), green (G), and blue (B) light for each sub-pixel obtained by dividing one pixel into three. However, since about 2/3 of the backlight light applied to the liquid crystal panel is absorbed by the color filter, the color filter type liquid crystal display device has a problem that the light use efficiency is low. Therefore, a field sequential type liquid crystal display device that performs color display without using a color filter has attracted attention.
　フィールドシーケンシャル方式では、１画面の表示期間（１フレーム期間）を３つのサブフレーム期間に分割する。第１のサブフレーム期間には入力信号の赤色成分に応じた赤色の画像を表示し、第２のサブフレーム期間には緑色成分に応じた緑色の画像を表示し、第３のサブフレーム期間には青色成分に応じた青色の画像を表示することにより、液晶パネルにカラー画像を表示する。このようにフィールドシーケンシャル方式の液晶表示装置では、カラーフィルタが不要になるので、カラーフィルタ方式の液晶表示装置に比べて光利用効率が約３倍になる。 In the field sequential method, one screen display period (one frame period) is divided into three subframe periods. A red image corresponding to the red component of the input signal is displayed in the first subframe period, a green image corresponding to the green component is displayed in the second subframe period, and the third subframe period is displayed in the third subframe period. Displays a color image on the liquid crystal panel by displaying a blue image corresponding to the blue component. Thus, the field sequential type liquid crystal display device eliminates the need for a color filter, so that the light utilization efficiency is about three times that of the color filter type liquid crystal display device.
　また、このようなフィールドシーケンシャル方式の液晶表示装置には、１フレーム期間を４つ以上のサブフレーム期間に分割するものがある。このサブフレーム期間には、赤色、緑色、および青色の他、黄色（Ｙ）、白色（Ｗ）、シアン（Ｃ）、マゼンタ（Ｍ）の少なくとも１つがそれぞれ割り当てられるものがある。これらの色の割り当ての順番は、予め定められていることが多いが、例えば入力データに応じて変更されるものもある。 In addition, there is a field sequential type liquid crystal display device that divides one frame period into four or more subframe periods. In this subframe period, in addition to red, green, and blue, at least one of yellow (Y), white (W), cyan (C), and magenta (M) is assigned. The order of assigning these colors is often determined in advance, but may be changed according to input data, for example.
　例えば日本特開２０１０－２２４０６５号公報には、装置の用途や動画画像の特性に応じて、上記色の割り当ての順番を適宜に変更するフィールドシーケンシャル方式の液晶表示装置の構成が記載されている。この構成により、より好ましい色選択および色順次表示が可能となる。 For example, Japanese Patent Application Laid-Open No. 2010-224065 describes a configuration of a field sequential type liquid crystal display device that appropriately changes the order of the color assignment according to the use of the device and the characteristics of a moving image. With this configuration, more preferable color selection and color sequential display are possible.
　また、日本特開２００３－２４１７１４号公報には、三原色の他に、黄色（Ｙ）および白色（Ｗ）を加えた各色を５つのサブフレーム期間に割り当てる構成、またはさらにシアン（Ｃ）を加えた各色を６つのサブフレーム期間に割り当てる構成が記載されている。 In Japanese Patent Laid-Open No. 2003-241714, a configuration in which each color including yellow (Y) and white (W) in addition to the three primary colors is assigned to five subframe periods, or cyan (C) is further added. A configuration is described in which each color is assigned to six subframe periods.
　さらに、日本特開２００３－２８０６１４号公報には、三原色の他に、黄色（Ｙ）、シアン（Ｃ）、およびマゼンタ（Ｍ）を加えた各色を６つのサブフレーム期間に割り当てる構成が記載されている。 Furthermore, Japanese Patent Laid-Open No. 2003-280614 describes a configuration in which each color including yellow (Y), cyan (C), and magenta (M) in addition to the three primary colors is assigned to six subframe periods. Yes.
日本特開２０１０－２２４０６５号公報Japanese Unexamined Patent Publication No. 2010-224065 日本特開２００３－２４１７１４号公報Japanese Unexamined Patent Publication No. 2003-241714 日本特開２００３－２８０６１４号公報Japanese Unexamined Patent Publication No. 2003-280614
　ここで、従来のフィールドシーケンシャル方式の液晶表示装置に画像を表示した場合の問題点を説明する。なお、以下の説明では、外部から液晶表示装置に与えられる入力信号の赤色成分、緑色成分、および青色成分は、それぞれ８ビットのデータであるとする。したがって、液晶表示装置は、赤色、緑色および青色の各色をそれぞれ２５６階調で表示する。 Here, the problem when an image is displayed on a conventional field sequential type liquid crystal display device will be described. In the following description, it is assumed that the red component, the green component, and the blue component of the input signal supplied to the liquid crystal display device from the outside are 8-bit data. Therefore, the liquid crystal display device displays each color of red, green, and blue with 256 gradations.
　この液晶表示装置に、隣接するサブフレーム期間の間で液晶パネルの透過率が大きく変化する画像を表示する場合について説明する。図９は、赤色、緑色、および青色を順次表示する従来のフィールドシーケンシャル方式の液晶表示装置に、黄色の静止画を表示させたときに、各サブフレーム期間における液晶パネルの輝度を示す図である。図９に示されるグラフの横軸は時間を、縦軸は液晶パネルの透過率をそれぞれ示している。 A case will be described in which an image in which the transmittance of the liquid crystal panel changes greatly between adjacent subframe periods is displayed on the liquid crystal display device. FIG. 9 is a diagram illustrating the luminance of the liquid crystal panel in each subframe period when a yellow still image is displayed on a conventional field sequential type liquid crystal display device that sequentially displays red, green, and blue. . The horizontal axis of the graph shown in FIG. 9 indicates time, and the vertical axis indicates the transmittance of the liquid crystal panel.
　図９に示すように、赤色の階調値が２５５、緑色の階調値が２５５、および青色の階調値が０である画像を表示する場合、第１のサブフレーム期間の後半の期間では、赤色バックライトが発光するとともに、赤色の階調値を２５５とする赤色成分が与えられる。このとき、液晶パネルの透過率は０％から時間とともに大きくなり、所定時間経過後に１００％になる。これによって、赤色バックライトからの赤色の光が液晶パネルを透過し、階調値が２５５の赤色の画像が表示される。 As shown in FIG. 9, when displaying an image with a red gradation value of 255, a green gradation value of 255, and a blue gradation value of 0, the second half of the first subframe period is displayed. The red backlight emits light and a red component having a red gradation value of 255 is given. At this time, the transmittance of the liquid crystal panel increases from 0% with time, and reaches 100% after a predetermined time. As a result, red light from the red backlight is transmitted through the liquid crystal panel, and a red image having a gradation value of 255 is displayed.
　しかし、本来、液晶パネルの透過率は赤色バックライトの点灯中は１００％になっていなければならない。にもかかわらず、赤色の階調値を２５５とする赤色成分が与えられても、液晶パネルの透過率は、第１のサブフレーム期間における０％から瞬時に１００％になることはない。したがって、この間に液晶パネルを透過するべき赤色バックライトからの赤色の光は輝度不足となり、暗い赤色の画像が表示されてしまう。 However, the transmittance of the liquid crystal panel should be 100% when the red backlight is on. Nevertheless, even if a red component having a red gradation value of 255 is given, the transmittance of the liquid crystal panel does not instantaneously become 100% from 0% in the first subframe period. Therefore, the red light from the red backlight that should pass through the liquid crystal panel during this period has insufficient luminance, and a dark red image is displayed.
　続いて、第２のサブフレーム期間の後半の期間では、緑色バックライトが発光するとともに、緑色の階調値を２５５とする緑色成分が与えられる。このとき、第１のサブフレーム期間における液晶パネルの透過率は最終的に１００％になるので、第２のサブフレーム期間では、液晶パネルの透過率は始めから１００％である。したがって、液晶パネルを透過するべき緑色バックライトからの緑色の光が輝度不足となることはない。しかし、赤色の光が上述のように輝度不足となる結果、視聴者は、赤色と緑色とが正しく混色した黄色の画像ではなく、緑がかった黄緑色の画像を見ることになる。このような緑色が大きく混色した黄色は、本来表示されるべき黄色と色相が異なる色となる。 Subsequently, in the second half of the second subframe period, the green backlight emits light and a green component having a green gradation value of 255 is given. At this time, the transmittance of the liquid crystal panel in the first subframe period finally becomes 100%. Therefore, in the second subframe period, the transmittance of the liquid crystal panel is 100% from the beginning. Therefore, the green light from the green backlight that should pass through the liquid crystal panel does not become insufficient in luminance. However, as a result of the lack of brightness of red light as described above, the viewer sees a yellowish-green image with a green color instead of a yellow image in which red and green are correctly mixed. Such a yellow color in which green is greatly mixed is a color having a hue different from that of yellow that should be originally displayed.
　次に、第３のサブフレーム期間の後半の期間では、青色バックライトが発光するとともに、青色の階調値を０とする青色成分が与えられる。このとき、本来、液晶パネルの透過率は０％になり、青色バックライトの光は液晶パネルに遮られて、青色の画像は表示されないはずである。しかし、青色の階調値を０とする青色成分が与えられても、液晶パネルの透過率は、第２のサブフレーム期間における１００％から瞬時に０％になることはない。このように、第３のサブフレーム期間における液晶パネルの透過率は、第２のサブフレーム期間における透過率の影響を受けるので、液晶パネルの透過率が本来の０％になるまでに時間を要する。この間に、液晶パネルに遮られるべき青色バックライトからの青色の光の一部が透過し、青色の画像が表示されてしまう。この結果、視聴者は、青色が混色した画像を見ることになり、色再現性が低下してしまう。 Next, in the second half of the third subframe period, the blue backlight emits light and a blue component having a blue gradation value of 0 is given. At this time, the transmittance of the liquid crystal panel is originally 0%, and the light of the blue backlight is blocked by the liquid crystal panel, and the blue image should not be displayed. However, even if a blue component having a blue gradation value of 0 is given, the transmittance of the liquid crystal panel does not instantaneously become 0% from 100% in the second subframe period. Thus, since the transmittance of the liquid crystal panel in the third subframe period is affected by the transmittance in the second subframe period, it takes time until the transmittance of the liquid crystal panel becomes 0%. . During this time, part of the blue light from the blue backlight to be blocked by the liquid crystal panel is transmitted, and a blue image is displayed. As a result, the viewer sees an image in which blue is mixed, and color reproducibility deteriorates.
　そこで上記日本特開２０１０－２２４０６５号公報に記載された構成のように、上記色の割り当ての順番を適宜に変更すれば、より好ましい色選択および色順次表示が可能となり、色再現性を向上させることができる。しかし、画像データに応じて色順序を頻繁に変更することによって、色割れやフリッカが視認されることが考えられる。また、色順序を高速に変更するためには高速な制御回路が必要となり、装置の製造コストが上昇する。 Therefore, as in the configuration described in Japanese Patent Application Laid-Open No. 2010-224065, if the order of the color assignment is changed appropriately, more preferable color selection and color sequential display are possible, and color reproducibility is improved. be able to. However, it is conceivable that color breaks and flicker are visually recognized by frequently changing the color order according to the image data. Further, in order to change the color order at high speed, a high-speed control circuit is required, which increases the manufacturing cost of the apparatus.
　そこで、本発明は、色順序を固定することにより色割れやフリッカの発生を防止し、かつ色再現性の低下が抑制されたフィールドシーケンシャル方式の表示装置を提供することを目的とする。 Therefore, an object of the present invention is to provide a field sequential display device in which the occurrence of color breakup and flicker is prevented by fixing the color order and the decrease in color reproducibility is suppressed.
　本発明の第１の局面は、１フレーム期間を複数のサブフレーム期間に分割し、サブフレーム期間毎に異なる色の画像を表示する表示装置であって、
　マトリクス状に配置された複数の画素形成部を含む表示パネルと、
　入力信号に基づいて、前記サブフレーム期間毎に前記複数の画素形成部の光の透過率を制御する補正映像信号を出力する表示制御回路と、
　前記補正映像信号に基づいて前記複数の画素形成部を駆動する駆動回路とを備え、
　前記表示制御回路は、前記サブフレーム期間のうちの１つで前記表示パネルに黄色の画像が表示され、当該黄色の画像が表示されるサブフレーム期間の直後のサブフレーム期間で前記表示パネルに白色または青色の画像が表示されるよう、前記異なる色を前記複数のサブフレーム期間に割り当てた前記補正映像信号を出力することを特徴とする。 A first aspect of the present invention is a display device that divides one frame period into a plurality of subframe periods and displays images of different colors for each subframe period,
A display panel including a plurality of pixel formation portions arranged in a matrix;
A display control circuit that outputs a corrected video signal for controlling the light transmittance of the plurality of pixel forming units for each subframe period based on an input signal;
A drive circuit that drives the plurality of pixel forming units based on the corrected video signal,
The display control circuit displays a yellow image on the display panel in one of the subframe periods, and displays white on the display panel in a subframe period immediately after the subframe period in which the yellow image is displayed. Alternatively, the corrected video signal in which the different color is assigned to the plurality of subframe periods is output so that a blue image is displayed.
　本発明の第２の局面は、本発明の第１の局面において、
　前記表示制御回路は、赤色、緑色、および青色を所定の順番で前記複数のサブフレーム期間に割り当てることを特徴とする。 According to a second aspect of the present invention, in the first aspect of the present invention,
The display control circuit assigns red, green, and blue to the plurality of subframe periods in a predetermined order.
　本発明の第３の局面は、本発明の第２の局面において、
　前記表示制御回路は、前記直後のサブフレーム期間で白色の画像が表示される場合、赤色、緑色、および青色を前記複数のサブフレーム期間のうちの連続する３つに割り当てることを特徴とする。 According to a third aspect of the present invention, in the second aspect of the present invention,
The display control circuit assigns red, green, and blue to three consecutive subframe periods when a white image is displayed in the immediately following subframe period.
　本発明の第４の局面は、本発明の第２の局面において、
　前記表示制御回路は、前記直後のサブフレーム期間で青色の画像が表示される場合、緑色および赤色をその順番で前記複数のサブフレーム期間のうちの連続する２つに割り当てることを特徴とする。 According to a fourth aspect of the present invention, in the second aspect of the present invention,
When a blue image is displayed in the immediately following subframe period, the display control circuit assigns green and red to two consecutive subframe periods in that order.
　本発明の第５の局面は、本発明の第２の局面において、
　前記表示制御回路は、シアン色およびマゼンタ色の少なくとも一方を前記複数のサブフレーム期間に割り当てることを特徴とする。 According to a fifth aspect of the present invention, in the second aspect of the present invention,
The display control circuit assigns at least one of cyan and magenta colors to the plurality of subframe periods.
　本発明の第６の局面は、本発明の第５の局面において、
　前記表示制御回路は、
　　シアン色を割り当てる場合には、シアン色および赤色をその順番で前記複数のサブフレーム期間のうちの連続する２つに割り当て、
　　マゼンタ色を割り当てる場合には、マゼンタ色および緑色をその順番で前記複数のサブフレーム期間のうちの連続する２つに割り当てることを特徴とする。 A sixth aspect of the present invention is the fifth aspect of the present invention,
The display control circuit includes:
When assigning cyan, assign cyan and red in that order to two consecutive subframe periods,
When magenta color is assigned, magenta color and green color are assigned in order to two consecutive subframe periods.
　本発明の第７の局面は、本発明の第１の局面において、
　前記画素形成部は、光の透過率を制御される液晶素子を含むことを特徴とする。 According to a seventh aspect of the present invention, in the first aspect of the present invention,
The pixel formation unit may include a liquid crystal element whose light transmittance is controlled.
　本発明の第８の局面は、マトリクス状に配置された複数の画素形成部を含む表示パネルに、１フレーム期間を複数のサブフレーム期間に分割し、サブフレーム期間毎に異なる色の画像を表示する表示方法であって、
　入力信号に基づいて、前記サブフレーム期間毎に前記複数の画素形成部の光の透過率を制御する補正映像信号を出力する表示制御ステップと、
　前記補正映像信号に基づいて前記複数の画素形成部を駆動する駆動ステップとを備え、
　前記表示制御ステップでは、前記サブフレーム期間のうちの１つで前記表示パネルに黄色の画像が表示され、当該黄色の画像が表示されるサブフレーム期間の直後のサブフレーム期間で前記表示パネルに白色または青色の画像が表示されるよう、前記異なる色を前記複数のサブフレーム期間に割り当てた前記補正映像信号を出力することを特徴とする。 According to an eighth aspect of the present invention, one frame period is divided into a plurality of subframe periods on a display panel including a plurality of pixel formation portions arranged in a matrix, and images of different colors are displayed for each subframe period. Display method,
A display control step of outputting a corrected video signal for controlling the light transmittance of the plurality of pixel forming units for each subframe period based on an input signal;
A driving step of driving the plurality of pixel forming units based on the corrected video signal,
In the display control step, a yellow image is displayed on the display panel in one of the subframe periods, and a white color is displayed on the display panel in a subframe period immediately after the subframe period in which the yellow image is displayed. Alternatively, the corrected video signal in which the different color is assigned to the plurality of subframe periods is output so that a blue image is displayed.
　上記本発明の第１の局面によれば、黄色が表示されるサブフレーム期間の直後のサブフレーム期間で白色または青色が表示されるよう、各色を複数のサブフレーム期間に割り当てるので、色再現性の低下を抑制し、装置の表示品質を向上することができる。 According to the first aspect of the present invention, each color is assigned to a plurality of subframe periods so that white or blue is displayed in a subframe period immediately after the subframe period in which yellow is displayed. The display quality of the apparatus can be improved.
　上記本発明の第２の局面によれば、赤色、緑色、および青色を所定の順番で複数のサブフレーム期間に割り当てることにより、周知の三原色を使用した表示装置を使用することができる。 According to the second aspect of the present invention, a display device using known three primary colors can be used by assigning red, green, and blue to a plurality of subframe periods in a predetermined order.
　上記本発明の第３の局面によれば、赤色、緑色、および青色を複数のサブフレーム期間のうちの連続する３つに割り当てることにより、色再現性が良好な表示を行うことができる。 According to the third aspect of the present invention, it is possible to perform display with good color reproducibility by assigning red, green, and blue to three consecutive subframe periods.
　上記本発明の第４の局面によれば、視感効率の高い方である緑色を視感効率の低い方である赤色より前に割り当てることにより、色再現性を高めることができる。 According to the fourth aspect of the present invention, the color reproducibility can be improved by assigning the green color having the higher luminous efficiency before the red color having the lower luminous efficiency.
　上記本発明の第５の局面によれば、シアン色およびマゼンタ色の少なくとも一方を複数のサブフレーム期間に割り当てることにより、周知の三原色に加えて、周知の追加色を使用した表示装置を使用することができ、色表現性を高めることができる。 According to the fifth aspect of the present invention, a display device using a known additional color in addition to the known three primary colors is used by assigning at least one of cyan and magenta colors to a plurality of subframe periods. Color expression can be improved.
　上記本発明の第６の局面によれば、周知の三原色に加えて、周知の追加色を使用した表示装置で色表現性が良好な表示を行うことができ、さらに色再現性を高めることができる。 According to the sixth aspect of the present invention, in addition to the known three primary colors, a display device using a known additional color can perform display with good color expression and further improve color reproducibility. it can.
　上記本発明の第７の局面によれば、一般的な液晶表示装置を使用することができる。 According to the seventh aspect of the present invention, a general liquid crystal display device can be used.
　上記本発明の第８の局面によれば、上記本発明の第１の局面における効果と同様の効果を奏することができる。 According to the eighth aspect of the present invention, the same effects as in the first aspect of the present invention can be achieved.
本発明の第１の実施形態に係るフィールドシーケンシャル方式の液晶表示装置の構成を示すブロック図である。1 is a block diagram illustrating a configuration of a field sequential type liquid crystal display device according to a first embodiment of the present invention. FIG. 上記実施形態において、各サブフレーム期間の表示色とその点灯期間とを示す図である。In the said embodiment, it is a figure which shows the display color of each sub-frame period, and its lighting period. 上記実施形態の液晶表示装置に黄色の静止画を表示させたときの第４および第５のサブフレーム期間における液晶パネルの輝度を示す図である。It is a figure which shows the brightness | luminance of the liquid crystal panel in the 4th and 5th sub-frame period when a yellow still image is displayed on the liquid crystal display device of the said embodiment. 視感効率と光波長との関係を示すグラフ図である。It is a graph which shows the relationship between luminous efficiency and a light wavelength. 本発明の第２の実施形態において、各サブフレーム期間の表示色とその点灯期間とを示す図である。It is a figure which shows the display color of each sub-frame period, and its lighting period in the 2nd Embodiment of this invention. 上記実施形態において、各サブフレーム期間の表示色とその点灯期間との別例を示す図である。In the said embodiment, it is a figure which shows another example of the display color of each sub-frame period, and its lighting period. 本発明の第３の実施形態において、各サブフレーム期間の表示色とその点灯期間とを示す図である。It is a figure which shows the display color of each sub-frame period, and its lighting period in the 3rd Embodiment of this invention. 本発明の第４の実施形態において、各サブフレーム期間の表示色とその点灯期間とを示す図である。It is a figure which shows the display color of each sub-frame period, and its lighting period in the 4th Embodiment of this invention. 従来の液晶表示装置に黄色の静止画を表示させたときの各サブフレーム期間における液晶パネルの輝度を示す図である。It is a figure which shows the brightness | luminance of the liquid crystal panel in each sub-frame period when a yellow still image is displayed on the conventional liquid crystal display device.
＜１．第１の実施形態＞
＜１．１　液晶表示装置の構成＞
　図１は、本発明の第１の実施形態に係るフィールドシーケンシャル方式の液晶表示装置１０の構成を示すブロック図である。図１に示す液晶表示装置１０は、１フレーム期間を５つのサブフレーム期間に分割するフィールドシーケンシャルカラー方式によってカラー表示を行う。液晶表示装置１０は、液晶パネル１１と、タイミング制御回路１２と、バックライト制御回路１３と、表示制御回路１６と、走査信号線駆動回路１７と、映像信号線駆動回路１８と、バックライトユニット２０と、スイッチ群２１と、電源回路２２とを備えている。 <1. First Embodiment>
<1.1 Configuration of liquid crystal display device>
FIG. 1 is a block diagram showing a configuration of a field sequential type liquid crystal display device 10 according to the first embodiment of the present invention. The liquid crystal display device 10 shown in FIG. 1 performs color display by a field sequential color system that divides one frame period into five subframe periods. The liquid crystal display device 10 includes a liquid crystal panel 11, a timing control circuit 12, a backlight control circuit 13, a display control circuit 16, a scanning signal line drive circuit 17, a video signal line drive circuit 18, and a backlight unit 20. And a switch group 21 and a power supply circuit 22.
　以下の説明では、１フレーム期間を１／６０秒とし、各サブフレーム期間をそれぞれ１／３００秒とするが、周知の表示期間であればその長さは特に限定されない。また、外部から液晶表示装置１０に入力される入力信号の赤色成分（赤色の階調値）、緑色成分（緑色の階調値）、および青色成分（青色の階調値）はそれぞれ８ビットのデータであるものとする。 In the following description, one frame period is 1/60 seconds and each subframe period is 1/300 seconds. However, the length is not particularly limited as long as it is a known display period. The red component (red tone value), green component (green tone value), and blue component (blue tone value) of the input signal input to the liquid crystal display device 10 from the outside are each 8 bits. It is assumed to be data.
　液晶パネル１１には、複数本（ｍ本）の映像信号線Ｓ１～Ｓｍと、複数本（ｎ本）の走査信号線Ｇ１～Ｇｎと、それら複数本の映像信号線Ｓ１～Ｓｍと複数本の走査信号線Ｇ１～Ｇｎとの交差点にそれぞれ対応して設けられた複数個（ｍ×ｎ個）の画素形成部３０が含まれている。各画素形成部３０には、スイッチング素子として機能するＴＦＴ３１と、ＴＦＴ３１のドレイン端子に接続された画素電極３２と、画素電極３２とともに液晶容量を形成する共通電極３３が含まれている。ＴＦＴ３１のゲート端子は走査信号線Ｇｉ（１≦ｉ≦ｎ）に接続され、ソース端子は映像信号線Ｓｊ（１≦ｊ≦ｍ）に接続されている。 The liquid crystal panel 11 includes a plurality (m) of video signal lines S1 to Sm, a plurality (n) of scanning signal lines G1 to Gn, a plurality of video signal lines S1 to Sm and a plurality of video signal lines. A plurality (m × n) of pixel forming portions 30 provided corresponding to the intersections with the scanning signal lines G1 to Gn are included. Each pixel forming portion 30 includes a TFT 31 that functions as a switching element, a pixel electrode 32 connected to the drain terminal of the TFT 31, and a common electrode 33 that forms a liquid crystal capacitance together with the pixel electrode 32. The gate terminal of the TFT 31 is connected to the scanning signal line Gi (1 ≦ i ≦ n), and the source terminal is connected to the video signal line Sj (1 ≦ j ≦ m).
　外部から、入力信号ＤＶがタイミング制御回路１２と表示制御回路１６とに入力される。タイミング制御回路１２は、バックライトユニット２０に含まれる赤色、緑色、および青色ＬＥＤ（Light Emitting Diode）２０ｒ、２０ｇ、２０ｂを発光させるタイミングと、映像信号線駆動回路１８が、赤色、緑色、および青色の駆動用画像信号を映像信号線Ｓ１～Ｓｍに出力するタイミングとが一致するように、入力信号ＤＶに基づいて制御信号Ｃ１、Ｃ２を生成する。タイミング制御回路１２は、制御信号Ｃ１を表示制御回路１６に与え、制御信号Ｃ２をバックライト制御回路１３に与える。 The input signal DV is input to the timing control circuit 12 and the display control circuit 16 from the outside. The timing control circuit 12 is configured to emit red, green, and blue LEDs (Light Emitting Diodes) 20r, 20g, and 20b included in the backlight unit 20, and the video signal line driving circuit 18 is configured to perform red, green, and blue. The control signals C1 and C2 are generated based on the input signal DV so that the timings for outputting the driving image signals to the video signal lines S1 to Sm coincide with each other. The timing control circuit 12 gives the control signal C1 to the display control circuit 16 and gives the control signal C2 to the backlight control circuit 13.
　表示制御回路１６は、赤色（Ｒ）、緑色（Ｇ）、および青色（Ｂ）の各階調値を表す入力信号ＤＶに基づき、黄色（Ｙ）および白色（Ｗ）の各階調値を加え、さらに補正された赤色、緑色、および青色の各階調値の合計５種類の色の階調値を表す補正映像信号ＣＶを出力する。このように３つの原色（ＲＧＢ）からなる或る画素の入力階調値から、５つの表示色（ＲＧＢＹＷ）からなる或る画素の表示階調値を算出する方法は周知であり、例えば、三原色（ＲＧＢ）からなる或る階調値から、所定の色配分アルゴリズムに基づき５つの表示色（ＲＧＢＹＷ）からなる階調値を生成する。この色配分アルゴリズムは、周知のどのようなアルゴリズムであってもよい。例えば画面全体に渡って各色の色バランスやガンマ特性などを考慮して無彩色成分すなわち白色（Ｗ）を所定量だけ抽出し、当該無彩色成分が除去された各階調値（ＲＧＢ）に基づき、均等な配分割合となるように残りの４つの表示色（ＲＧＢＹ）からなる階調値を決定する。このようにして決定された各階調値は、補正映像信号ＣＶとして映像信号線駆動回路１８に与えられる。 The display control circuit 16 adds the gradation values of yellow (Y) and white (W) based on the input signal DV representing the gradation values of red (R), green (G), and blue (B), and A corrected video signal CV representing the gradation values of a total of five kinds of corrected red, green, and blue gradation values is output. A method for calculating the display gradation value of a certain pixel composed of five display colors (RGBYW) from the input gradation value of a certain pixel composed of three primary colors (RGB) is well known. For example, the three primary colors From a certain gradation value composed of (RGB), gradation values composed of five display colors (RGBYW) are generated based on a predetermined color distribution algorithm. This color allocation algorithm may be any known algorithm. For example, a predetermined amount of an achromatic color component, that is, white (W) is extracted in consideration of the color balance and gamma characteristics of each color over the entire screen, and based on each gradation value (RGB) from which the achromatic color component is removed, The gradation values composed of the remaining four display colors (RGBY) are determined so that the distribution ratio is uniform. Each gradation value determined in this way is supplied to the video signal line drive circuit 18 as a corrected video signal CV.
　表示制御回路１６は、タイミング制御回路１２から与えられた制御信号Ｃ１と、外部から入力された入力信号ＤＶとに基づいて、走査信号線駆動回路１７に対する制御信号（例えば、ゲートクロック信号など）Ｃ３と、映像信号線駆動回路１８に対する制御信号（例えば、ソースクロック信号など）Ｃ４とを生成する。表示制御回路１６は、制御信号Ｃ４を映像信号線駆動回路１８に与え、制御信号Ｃ３を走査信号線駆動回路１７に与える。 The display control circuit 16 controls the scanning signal line driving circuit 17 (for example, a gate clock signal) C3 based on the control signal C1 given from the timing control circuit 12 and the input signal DV inputted from the outside. And a control signal (for example, a source clock signal) C4 for the video signal line driving circuit 18 is generated. The display control circuit 16 gives the control signal C4 to the video signal line drive circuit 18 and gives the control signal C3 to the scanning signal line drive circuit 17.
　走査信号線駆動回路１７は、制御信号Ｃ３に基づいて各走査信号線Ｇ１～Ｇｎに、アクティブな走査信号を順に出力する。映像信号線駆動回路１８は、補正映像信号ＣＶに基づいて駆動用画像信号を生成し、制御信号Ｃ４によって決まるタイミングで各映像信号線Ｓ１～Ｓｍに駆動用画像信号を出力する。映像信号線Ｓ１～Ｓｍに出力された駆動用画像信号は、アクティブな走査信号線Ｇ１～Ｇｎに接続されたＴＦＴ３１を介して画素容量に与えられる。これにより、駆動用画像信号に応じた電圧が液晶に印加され、液晶の透過率が印加された電圧に応じて変化するので、画像が液晶パネル１１に表示される。なお、走査信号線駆動回路１７と映像信号線駆動回路１８とを合わせて、以下では単に駆動回路と呼ぶこともある。 The scanning signal line driving circuit 17 sequentially outputs active scanning signals to the scanning signal lines G1 to Gn based on the control signal C3. The video signal line drive circuit 18 generates a drive image signal based on the corrected video signal CV, and outputs the drive image signal to each of the video signal lines S1 to Sm at a timing determined by the control signal C4. The driving image signals output to the video signal lines S1 to Sm are given to the pixel capacitors via the TFTs 31 connected to the active scanning signal lines G1 to Gn. Accordingly, a voltage corresponding to the driving image signal is applied to the liquid crystal, and the transmittance of the liquid crystal changes according to the applied voltage, so that an image is displayed on the liquid crystal panel 11. Note that the scanning signal line driving circuit 17 and the video signal line driving circuit 18 together may be simply referred to as a driving circuit below.
　バックライトユニット２０は、２次元状に配置された赤色ＬＥＤ（Light Emitting Diode）２０ｒ、緑色ＬＥＤ２０ｇ、および青色ＬＥＤ２０ｂを含む。赤色ＬＥＤ２０ｒ、緑色ＬＥＤ２０ｇ、および青色ＬＥＤ２０ｂは、スイッチ群２１を介して電源回路２２にそれぞれ独立して接続されている。バックライト制御回路１３は、タイミング制御回路１２から与えられる制御信号Ｃ２に基づいてサブフレーム期間ごとにスイッチ群２１に含まれる各スイッチを適宜にオンする（導通状態にする）ためのバックライト制御信号ＢＣを生成し、バックライト制御信号ＢＣをスイッチ群２１に与える。 The backlight unit 20 includes a two-dimensionally arranged red LED (Light Emitting Diode) 20r, a green LED 20g, and a blue LED 20b. The red LED 20r, the green LED 20g, and the blue LED 20b are each independently connected to the power supply circuit 22 via the switch group 21. The backlight control circuit 13 is a backlight control signal for appropriately turning on (turning on) each switch included in the switch group 21 for each subframe period based on the control signal C2 provided from the timing control circuit 12. BC is generated and the backlight control signal BC is supplied to the switch group 21.
　スイッチ群２１は、バックライト制御信号ＢＣに基づいて、赤色ＬＥＤ２０ｒ、緑色ＬＥＤ２０ｇ、および青色ＬＥＤ２０ｂの１つ以上を、電源回路２２に対して適宜のタイミングで接続することにより電源電圧を与える。これにより、赤色ＬＥＤ２０ｒ、緑色ＬＥＤ２０ｇ、および青色ＬＥＤ２０ｂの１つ以上は、駆動用画像信号が映像信号線Ｓ１～Ｓｍに印加されるタイミングに合わせて後述するように発光し、サブフレーム期間ごとに液晶パネル１１の背面から赤色、緑色、および青色の光の１つ以上を照射する。例えば、赤色および緑色の光が照射される場合には、混色されることにより黄色が表示色となり、赤色、緑色、および青色の光が照射される場合には、混色されることにより白色が表示色となる。 The switch group 21 applies a power supply voltage by connecting one or more of the red LED 20r, the green LED 20g, and the blue LED 20b to the power supply circuit 22 at an appropriate timing based on the backlight control signal BC. Accordingly, one or more of the red LED 20r, the green LED 20g, and the blue LED 20b emit light as described later in accordance with the timing at which the driving image signal is applied to the video signal lines S1 to Sm, and the liquid crystal is displayed every subframe period. One or more of red, green, and blue light is emitted from the back of the panel 11. For example, when red and green light is irradiated, yellow is displayed when mixed, and when red, green, and blue light is irradiated, white is displayed when mixed. Become a color.
　なお、上記黄色を表示するために新たに黄色ＬＥＤが設けられてもよいし、上記白色を表示するために新たに白色ＬＥＤが設けられてもよい。また、バックライトユニット２０に含まれる光源として、赤色、緑色および青色ＬＥＤ２０ｒ、２０ｇ、２０ｂの代わりに、赤色、緑色および青色のＣＣＦＬ（Cold Cathode Fluorescent Lamp）など周知の光源を使用してもよい。 Note that a yellow LED may be newly provided to display the yellow color, or a white LED may be newly provided to display the white color. Further, as the light source included in the backlight unit 20, a known light source such as red, green, and blue CCFL (Cold Cathode Fluorescent Lamp) may be used instead of the red, green, and blue LEDs 20r, 20g, and 20b.
　本実施形態における液晶表示装置１０は、１フレーム期間を第１から第５までのサブフレーム期間に分割し、各サブフレーム期間に割り当てられる表示色を図２に示す順番で表示する。以下、図２から図４までを参照して、各サブフレーム期間における表示について説明する。 The liquid crystal display device 10 according to this embodiment divides one frame period into first to fifth subframe periods, and displays the display colors assigned to the subframe periods in the order shown in FIG. Hereinafter, display in each subframe period will be described with reference to FIGS.
＜１．２　各サブフレーム期間における表示＞
　図２は、各サブフレーム期間における表示色とその点灯期間とを示す図である。図２に示されるように、１フレーム期間は、第１から第５までの５つのサブフレーム期間に分割されており、各サブフレーム期間の前半は、非点灯期間であり、後半が点灯期間である。このように前半が非点灯期間となっているのは、前フレームにおける表示色と混色することにより色再現性が低下することを防ぐためである。なお、図２における非点灯期間は、１／２フレーム期間であるが、その長さは特に限定されず、省略することも可能である。 <1.2 Display in each subframe period>
FIG. 2 is a diagram showing display colors and their lighting periods in each subframe period. As shown in FIG. 2, one frame period is divided into five subframe periods from first to fifth. The first half of each subframe period is a non-lighting period and the second half is a lighting period. is there. The reason why the first half is in the non-lighting period is to prevent color reproducibility from deteriorating due to color mixing with the display color in the previous frame. Note that the non-lighting period in FIG. 2 is a ½ frame period, but the length thereof is not particularly limited and may be omitted.
　また、各サブフレーム期間の前半では、各画素形成部の画素容量に駆動用画像信号に対応する電圧が印加されるが、以下では説明の便宜のため、非常に短い時間で全ての画素容量への充電が完了するものとする。 Further, in the first half of each subframe period, a voltage corresponding to the driving image signal is applied to the pixel capacitance of each pixel formation unit. However, for the convenience of explanation, all the pixel capacitances are applied in a very short time. Shall be charged.
　本実施形態では、第１のサブフレーム期間に割り当てられる表示色は、赤色（Ｒ）であり、第２のサブフレーム期間に割り当てられる表示色は、緑色（Ｇ）であり、第３のサブフレーム期間に割り当てられる表示色は、青色（Ｂ）であるが、このように１フレーム期間において予め定められた表示順序は、少なくとも装置の表示動作中は変更されないことが好ましい。順序が変更されると、色割れやフリッカが発生することがあり、表示品位が低下するからである。ただし変更される場合であっても、後述する効果を得ることができるため、当該順序を適宜に変更することは可能である。また、これら三原色は、第１から第３までのサブフレーム期間（または後述するように第３から第５までのサブフレーム期間）において、所定の順番で表示されればよく、図２に示す順番には限定されない。 In the present embodiment, the display color assigned to the first subframe period is red (R), the display color assigned to the second subframe period is green (G), and the third subframe. Although the display color assigned to the period is blue (B), it is preferable that the display order determined in advance in one frame period is not changed at least during the display operation of the apparatus. This is because, when the order is changed, color breakage and flicker may occur, and the display quality deteriorates. However, even if it is changed, the effect described later can be obtained, so that the order can be appropriately changed. Further, these three primary colors may be displayed in a predetermined order in the first to third subframe periods (or the third to fifth subframe periods as will be described later), and the order shown in FIG. It is not limited to.
　さらに本実施形態では、第４のサブフレーム期間に割り当てられる表示色は、黄色（Ｙ）であり、第５のサブフレーム期間に割り当てられる表示色は、白色（Ｗ）であるが、このように黄色を表示した直後に白色を表示するという表示順序が本発明に特有の構成の一つとなっている。そのため、上述した三原色の場合とは異なり、この順序は固定されていなければならない。この特徴的な構成によって、後述するように黄色系の色再現性が向上し、表示品質を上げることができる。なお、もう一つの特有の構成については後述する。 Furthermore, in the present embodiment, the display color assigned to the fourth subframe period is yellow (Y), and the display color assigned to the fifth subframe period is white (W). The display order in which white is displayed immediately after displaying yellow is one of the configurations unique to the present invention. Therefore, unlike the case of the three primary colors described above, this order must be fixed. This characteristic configuration improves yellow color reproducibility and improves display quality as will be described later. Another specific configuration will be described later.
　もっとも、黄色を表示する前に、赤色、青色、および緑色のいずれが表示されていてもよいし、黄色が第１のサブフレーム期間において表示される構成であってもよい。また、白色を表示した後に赤色、青色、緑色のいずれが表示されてもよい。ただし、赤色、青色、および緑色の表示は、連続する３つのサブフレーム期間内になされる方が色再現性が良くなり、表示品質が向上するため好ましい。したがって、上記三原色は、第１から第３まで、または第３から第５までの、いずれかの連続するサブフレーム期間において、所定の順番で表示されることが好ましい。さらにこの順番は、赤色、青色、および緑色の順番であることが好ましい。すなわち、色再現性を高めるためには、後述するように、視感効率の高い順に、緑色、赤色、および青色の順番が最も好ましいようにも思われる。しかし、黄色の色再現性を高める本願の構成では、シアン色およびマゼンタ色の色再現性を高めるために、赤色の次に青色を割り当て、緑色の次に青色を割り当てることが好ましく、その逆の順番は好ましくないことがある。さらに、より視感効率の高いシアン色の色再現性を高めることが好ましい。これらのことから、青色の次に赤色を割り当てないよう、赤色、緑色、および青色の順番で割り当てることで、色再現性の低下を最も抑制することができる。 Of course, any of red, blue, and green may be displayed before yellow is displayed, or a configuration in which yellow is displayed in the first subframe period may be employed. In addition, any of red, blue, and green may be displayed after displaying white. However, red, blue, and green are preferably displayed within three consecutive subframe periods because color reproducibility is improved and display quality is improved. Therefore, it is preferable that the three primary colors are displayed in a predetermined order in any one of the continuous subframe periods from the first to the third or the third to the fifth. Furthermore, this order is preferably red, blue and green. That is, in order to improve color reproducibility, it seems that the order of green, red, and blue is most preferable in the order of high luminous efficiency, as will be described later. However, in the configuration of the present application that enhances the color reproducibility of yellow, it is preferable to assign blue next to red and blue next to green in order to improve the color reproducibility of cyan and magenta, and vice versa. The order may be undesirable. Furthermore, it is preferable to improve the color reproducibility of cyan with higher luminous efficiency. From these facts, it is possible to suppress the deterioration in color reproducibility most by assigning red, green, and blue in this order so that red is not assigned next to blue.
　以上のように、第１のサブフレーム期間の前半において、各画素形成部３０は、表示制御回路１６によって変換された補正映像信号ＣＶの赤色を示す階調値に基づいて駆動され、その後半において赤色ＬＥＤ２０ｒが発光する。同様にして、第２のサブフレーム期間の前半において、各画素形成部３０は補正映像信号ＣＶの緑色を示す階調値に基づいて駆動され、その後半において緑色ＬＥＤ２０ｇが発光する。第３のサブフレーム期間の前半には、各画素形成部３０は補正映像信号ＣＶの青色を示す階調値に基づいて駆動され、その後半において青色ＬＥＤ２０ｂが発光する。 As described above, in the first half of the first subframe period, each pixel forming unit 30 is driven based on the gradation value indicating the red color of the corrected video signal CV converted by the display control circuit 16, and in the second half thereof. The red LED 20r emits light. Similarly, in the first half of the second subframe period, each pixel forming unit 30 is driven based on the gradation value indicating green of the corrected video signal CV, and the green LED 20g emits light in the latter half. In the first half of the third subframe period, each pixel forming unit 30 is driven based on the gradation value indicating blue of the corrected video signal CV, and the blue LED 20b emits light in the latter half.
　さらに、第４のサブフレーム期間の前半には、各画素形成部３０は補正映像信号ＣＶの黄色を示す階調値に基づいて駆動され、その後半には赤色ＬＥＤ２０ｒおよび緑色ＬＥＤ２０ｇが発光する。なお、赤色ＬＥＤ２０ｒおよび緑色ＬＥＤ２０ｇが発光する構成に替えて、新たに設けられる黄色ＬＥＤが発光する構成であってもよい。 Furthermore, in the first half of the fourth subframe period, each pixel forming unit 30 is driven based on the gradation value indicating yellow of the corrected video signal CV, and in the latter half, the red LED 20r and the green LED 20g emit light. In addition, it may replace with the structure which red LED 20r and green LED 20g light-emit, and the structure which yellow LED newly provided light-emits may be sufficient.
　次に、第５のサブフレーム期間の前半には、各画素形成部３０は補正映像信号ＣＶの白色を示す階調値に基づいて駆動され、その後半には赤色ＬＥＤ２０ｒ、緑色ＬＥＤ２０ｇ、および青色ＬＥＤ２０ｂが発光する。なお、これらのＬＥＤが発光する構成に替えて、新たに設けられる白色ＬＥＤが発光する構成であってもよい。 Next, in the first half of the fifth subframe period, each pixel forming unit 30 is driven based on the gradation value indicating white of the corrected video signal CV, and in the latter half, the red LED 20r, the green LED 20g, and the blue LED 20b. Emits light. In addition, it may replace with the structure which these LED light-emits, and the structure from which white LED newly provided light-emits may be sufficient.
　以上のように、液晶パネル１１の画面は、各サブフレーム期間において対応する階調値に応じた明るさで各色が次々と表示されるため、時間残像を利用することにより、液晶表示装置１０はカラー画像を表示することができる。次に、本実施形態の特徴的な構成である、第４および第５のサブフレーム期間における液晶パネルの表示について説明する。 As described above, the screen of the liquid crystal panel 11 displays each color one after another with the brightness corresponding to the corresponding gradation value in each subframe period. A color image can be displayed. Next, display of the liquid crystal panel in the fourth and fifth subframe periods, which is a characteristic configuration of the present embodiment, will be described.
　図３は、本実施形態の液晶表示装置に黄色の静止画を表示させたときの第４および第５のサブフレーム期間における液晶パネルの輝度を示す図である。この図３に示すグラフ図は、図９と同様に横軸は時間を、縦軸は液晶パネルの透過率をそれぞれ示している。また、ここでは隣接するサブフレーム期間の間で液晶パネルの透過率が大きく変化する画像として黄色の画像を表示するものとし、さらに説明の便宜のため、黄色の階調値が２５５であり、白色の階調値が０である画像を表示するものとする。なお実際には、第１から第３までのサブフレーム期間に割り当てられた赤色、緑色、および青色の表示階調との関係から黄色の階調値は２５５より小さく、また白色の階調値は０より大きいのが一般的である。また、説明の便宜上、各サブフレーム期間の開始時点から液晶パネルの透過率が変化するように示しているが、実際には各画素形成部における画素容量に電荷を保持させるため、所定の時間が必要である。 FIG. 3 is a diagram showing the luminance of the liquid crystal panel during the fourth and fifth subframe periods when a yellow still image is displayed on the liquid crystal display device of the present embodiment. In the graph shown in FIG. 3, the horizontal axis indicates time and the vertical axis indicates the transmittance of the liquid crystal panel, as in FIG. Here, a yellow image is displayed as an image in which the transmittance of the liquid crystal panel changes greatly between adjacent subframe periods, and for convenience of explanation, the yellow gradation value is 255 and the white color is white. An image having a gradation value of 0 is displayed. Actually, the yellow gradation value is smaller than 255 due to the relationship between the display gradations of red, green, and blue assigned to the first to third subframe periods, and the white gradation value is Generally it is greater than zero. For convenience of explanation, the transmittance of the liquid crystal panel is shown to change from the start of each subframe period. In practice, however, a predetermined time is required to hold the charge in the pixel capacitance in each pixel formation portion. is necessary.
　図３に示されるように、第４のサブフレーム期間の後半の期間では、赤色ＬＥＤ２０ｒおよび緑色ＬＥＤ２０ｇが発光するとともに、黄色の階調値を２５５とする駆動用画像信号が各画素形成部に入力される。このとき、液晶パネルの透過率は０％から時間とともに大きくなり、所定時間経過後に１００％になる。これによって、赤色ＬＥＤ２０ｒおよび緑色ＬＥＤ２０ｇの光が混色した黄色の光が液晶パネルを透過し、階調値が２５５の黄色の画像が表示される。 As shown in FIG. 3, in the second half of the fourth subframe period, the red LED 20r and the green LED 20g emit light, and a driving image signal having a yellow gradation value of 255 is input to each pixel formation unit. Is done. At this time, the transmittance of the liquid crystal panel increases from 0% with time, and reaches 100% after a predetermined time. As a result, yellow light in which light from the red LED 20r and green LED 20g is mixed is transmitted through the liquid crystal panel, and a yellow image having a gradation value of 255 is displayed.
　しかし、本来、液晶パネルの透過率は、赤色ＬＥＤ２０ｒおよび緑色ＬＥＤ２０ｇの点灯中１００％になっていなければならない。にもかかわらず、黄色の階調値を２５５とする駆動用画像信号が入力されても、液晶パネルの透過率は、（ここでは前サブフレーム期間の液晶パネルの透過率である）０％から瞬時に１００％になることはない。したがって、この間に液晶パネルを透過するべき黄色の混色光は輝度不足となり、やや暗い黄色の画像が表示される。 However, originally, the transmittance of the liquid crystal panel should be 100% during the lighting of the red LED 20r and the green LED 20g. Nevertheless, even when a driving image signal having a yellow gradation value of 255 is input, the transmittance of the liquid crystal panel is 0% (here, the transmittance of the liquid crystal panel in the previous subframe period). There is no instant 100%. Accordingly, the yellow mixed color light to be transmitted through the liquid crystal panel during this period is insufficient in luminance, and a slightly dark yellow image is displayed.
　続いて、第５のサブフレーム期間の後半の期間では、赤色ＬＥＤ２０ｒ、緑色ＬＥＤ２０ｇ、および青色ＬＥＤ２０ｂが発光するとともに、白色の階調値を０とする駆動用画像信号が各画素形成部に入力される。このとき、本来、液晶パネルの透過率は０％になり、バックライトからの（混色された）光は液晶パネルに遮られて、白色の画像は表示されないはずである。しかし、白色の階調値を０とする駆動用画像信号が入力されても、液晶パネルの透過率は、第４のサブフレーム期間における１００％から瞬時に０％になることはない。このように、第５のサブフレーム期間における液晶パネルの透過率は、第４のサブフレーム期間における透過率の影響を受けるので、液晶パネルの透過率が本来の０％になるまでに時間を要する。この間に、液晶パネルに遮られるべきバックライトからの白色の混色光の一部が透過し、白色の画像が表示されてしまう。この結果、視聴者は、白色が混色した黄色の画像を見ることになる。しかし、白色は無彩色であるため、混色により色バランスを大きく崩すことがない。その白色の輝度が小さければ、混色による色バランスの崩れは、より小さくなる。したがって、黄色の画像は、大きく色バランスを崩すことなく表示される。このことにより、装置の色再現性が向上し、表示品質が上がる。 Subsequently, in the second half of the fifth subframe period, the red LED 20r, the green LED 20g, and the blue LED 20b emit light, and a driving image signal with a white gradation value of 0 is input to each pixel formation unit. The At this time, the transmittance of the liquid crystal panel is originally 0%, and the light (mixed color) from the backlight is blocked by the liquid crystal panel, and a white image should not be displayed. However, even when a driving image signal having a white gradation value of 0 is input, the transmittance of the liquid crystal panel does not instantaneously become 0% from 100% in the fourth subframe period. As described above, since the transmittance of the liquid crystal panel in the fifth subframe period is affected by the transmittance in the fourth subframe period, it takes time until the transmittance of the liquid crystal panel becomes 0%. . During this time, a part of the white mixed light from the backlight to be blocked by the liquid crystal panel is transmitted, and a white image is displayed. As a result, the viewer sees a yellow image in which white is mixed. However, since white is an achromatic color, the color balance is not greatly lost due to color mixing. If the brightness of the white color is small, the color balance collapse due to the mixed color becomes smaller. Therefore, the yellow image is displayed without greatly losing the color balance. This improves the color reproducibility of the device and improves the display quality.
＜１．３　第１の実施形態の効果＞
　以上のように、本実施形態における液晶表示装置１０は、５つの表示色（ＲＧＢＹＷ）の各サブフレーム期間への割り当て順序（色順序）を固定することにより色割れやフリッカの発生を防止し、かつ黄色を割り当てたサブフレーム期間の直後のサブフレーム期間に白色を割り当てることにより、色再現性の低下を抑制することができる。 <1.3 Effects of First Embodiment>
As described above, the liquid crystal display device 10 according to the present embodiment prevents the occurrence of color breakup and flicker by fixing the allocation order (color order) of the five display colors (RGBYW) to each subframe period. In addition, by assigning white to the subframe period immediately after the subframe period to which yellow is assigned, it is possible to suppress a decrease in color reproducibility.
　このように、黄色の画像を表示した直後に白色の画像を表示する構成によって、黄色の画像の色バランスが保たれ、表示品質が上がることについて、図４を参照してさらに詳しく説明する。 In this way, the fact that the color balance of the yellow image is maintained and the display quality is improved by the configuration in which the white image is displayed immediately after the yellow image is displayed will be described in more detail with reference to FIG.
　図４は、視感効率と光波長との関係を示すグラフ図である。この図４に示されるように、（明所における）視感度は波長５５５ｎｍの（黄緑色の）光に対して最大になることが知られている。したがって、波長５８０ｎｍ前後である黄色の光に対する視感度は、他の色の光に比べて高くなっており、この黄色の色バランスが崩れると、他の色に比べて崩れが目立って感じられやすい。その結果、装置全体としての色再現性が低下し、表示品質が下がる。この点、本発明における上記構成によれば、黄色の画像は大きく色バランスを崩すことなく表示されるため、装置の色再現性の低下が抑制され、表示品質が向上するという効果が得られる。 FIG. 4 is a graph showing the relationship between luminous efficiency and light wavelength. As shown in FIG. 4, it is known that the visibility (in a bright place) is maximized with respect to (yellowish green) light having a wavelength of 555 nm. Therefore, the visibility to yellow light having a wavelength of around 580 nm is higher than that of light of other colors, and when this yellow color balance is lost, the collapse is more noticeable than other colors. . As a result, the color reproducibility of the entire apparatus is lowered and the display quality is lowered. In this respect, according to the above-described configuration of the present invention, the yellow image is displayed without greatly losing the color balance, so that the reduction in the color reproducibility of the apparatus is suppressed and the display quality is improved.
＜２．　第２の実施形態＞
＜２．１　液晶表示装置の構成＞
　本発明の第２の実施形態に係るフィールドシーケンシャル方式の液晶表示装置の全体構成は、第１の実施形態の場合と同様であり（図１を参照）、１フレーム期間を６つのサブフレーム期間に分割する点を除き、同様の動作を行うので、その説明を省略する。 <2. Second Embodiment>
<2.1 Configuration of liquid crystal display device>
The entire configuration of the field sequential type liquid crystal display device according to the second embodiment of the present invention is the same as that of the first embodiment (see FIG. 1), and one frame period is divided into six subframe periods. Since the same operation is performed except for the division, the description thereof is omitted.
　本実施形態における液晶表示装置は、６つのサブフレーム期間を使用する点で、第１の実施形態の場合と、表示制御回路１６の動作が一部異なる。すなわち、表示制御回路１６は、赤色（Ｒ）、緑色（Ｇ）、および青色（Ｂ）の各階調値を表す入力信号ＤＶに基づき、シアン色（Ｃ）、黄色（Ｙ）、および白色（Ｗ）の各階調値を加え、さらに補正された赤色、緑色、および青色の各階調値の合計６種類の色の階調値を表す補正映像信号ＣＶを出力する。なお、３つの原色（ＲＧＢ）からなる或る画素の入力階調値から、６つの表示色（ＲＧＢＣＹＷ）からなる或る画素の表示階調値を算出する方法は、第１の実施形態と同様に周知であるため説明を省略する。 The liquid crystal display device in this embodiment is partially different in operation of the display control circuit 16 from the first embodiment in that it uses six subframe periods. That is, the display control circuit 16 performs cyan (C), yellow (Y), and white (W) based on the input signal DV representing the gradation values of red (R), green (G), and blue (B). ), And the corrected video signal CV representing the gradation values of a total of six colors including the corrected red, green, and blue gradation values is output. A method for calculating display gradation values of a certain pixel composed of six display colors (RGBCYW) from input gradation values of a certain pixel composed of three primary colors (RGB) is the same as in the first embodiment. The description is omitted because it is well known.
　本実施形態における液晶表示装置１０は、１フレーム期間を第１から第６までのサブフレーム期間に分割し、各サブフレーム期間に割り当てられる表示色を図５に示す順番で表示する。以下、図５を参照して、各サブフレーム期間における表示について説明する。 The liquid crystal display device 10 according to the present embodiment divides one frame period into first to sixth subframe periods, and displays display colors assigned to the subframe periods in the order shown in FIG. Hereinafter, display in each subframe period will be described with reference to FIG.
＜２．２　各サブフレーム期間における表示＞
　図５は、本実施形態の各サブフレーム期間における表示色とその点灯期間とを示す図である。図５に示されるように、１フレーム期間は、第１から第６までの６つのサブフレーム期間に分割されており、各サブフレーム期間の前半は、非点灯期間であり、後半が点灯期間である。この点は、図２に示す場合と同様である。 <2.2 Display in each subframe period>
FIG. 5 is a diagram showing display colors and their lighting periods in each subframe period of the present embodiment. As shown in FIG. 5, one frame period is divided into six subframe periods from first to sixth. The first half of each subframe period is a non-lighting period, and the latter half is a lighting period. is there. This is the same as the case shown in FIG.
　また本実施形態は、第１の実施形態と同じ順番で、第２のサブフレーム期間に割り当てられる表示色は、赤色（Ｒ）であり、第３のサブフレーム期間に割り当てられる表示色は、緑色（Ｇ）であり、第４のサブフレーム期間に割り当てられる表示色は、青色（Ｂ）である。この表示順序は、前述したように少なくとも装置の表示動作中は変更されないことが好ましいが、適宜に変更することは可能である。また、これら三原色は、第２から第４までのサブフレーム期間（またはその他の連続するサブフレーム期間）において、所定の順番で表示されればよく、図５に示す順番には限定されない。 In the present embodiment, the display color assigned to the second subframe period is red (R) in the same order as the first embodiment, and the display color assigned to the third subframe period is green. (G), and the display color assigned to the fourth subframe period is blue (B). The display order is preferably not changed at least during the display operation of the apparatus as described above, but can be changed as appropriate. These three primary colors may be displayed in a predetermined order in the second to fourth subframe periods (or other consecutive subframe periods), and are not limited to the order shown in FIG.
　さらに本実施形態では、第５のサブフレーム期間に割り当てられる表示色は、黄色（Ｙ）であり、第６のサブフレーム期間に割り当てられる表示色は、白色（Ｗ）であるが、このように黄色を表示した直後に白色を表示するという表示順序が本発明に特有の構成の一つとなっている。このことは第１の実施形態と同様であり、同様にこの順序は固定されていなければならない。この特徴的な構成によって、第１の実施形態と同様に黄色系の色再現性が向上し、表示品質を上げることができる。 Further, in this embodiment, the display color assigned to the fifth subframe period is yellow (Y), and the display color assigned to the sixth subframe period is white (W). The display order in which white is displayed immediately after displaying yellow is one of the configurations unique to the present invention. This is the same as in the first embodiment, and this order must be fixed as well. With this characteristic configuration, yellow color reproducibility can be improved and display quality can be improved as in the first embodiment.
　もっとも、黄色を表示する前に、赤色、青色、緑色、およびシアン色のいずれが表示されていてもよいし、黄色が第１のサブフレーム期間において表示される構成であってもよい。また、白色を表示した後に赤色、青色、緑色、およびシアン色のいずれが表示されてもよい。ただし、赤色、青色、および緑色の表示は、連続する３つのサブフレーム期間内になされる方が色再現性が良くなり、表示品質が向上するため好ましい。さらにこの順番は、赤色、青色、および緑色の順番であることが好ましいことは前述したとおりであるが、第２のサブフレーム期間において赤色が割り当てられている理由については詳しく後述する。 However, before displaying yellow, any of red, blue, green, and cyan may be displayed, or yellow may be displayed in the first subframe period. In addition, any of red, blue, green, and cyan may be displayed after displaying white. However, red, blue, and green are preferably displayed within three consecutive subframe periods because color reproducibility is improved and display quality is improved. Further, as described above, it is preferable that the order is the order of red, blue, and green. The reason why red is assigned in the second subframe period will be described in detail later.
　まず、第１のサブフレーム期間の前半には、各画素形成部３０は補正映像信号ＣＶのシアン色を示す階調値に基づいて駆動され、その後半には緑色ＬＥＤ２０ｇおよび青色ＬＥＤ２０ｂが発光する。なお、緑色ＬＥＤ２０ｇおよび青色ＬＥＤ２０ｂが発光する構成に替えて、新たに設けられるシアン色ＬＥＤが発光する構成であってもよい。 First, in the first half of the first subframe period, each pixel forming unit 30 is driven based on the gradation value indicating the cyan color of the corrected video signal CV, and in the latter half, the green LED 20g and the blue LED 20b emit light. Instead of the configuration in which the green LED 20g and the blue LED 20b emit light, a configuration in which a newly provided cyan LED emits light may be used.
　ここで、シアン色の割り当ては適宜に行うことができるが、図５に示すように、シアン色の後に赤色を割り当てると色再現性がより高くなるため極めて好ましい。すなわち、シアン色（Ｃ）は緑色（Ｇ）と青色（Ｂ）との混色より表現されるため、直後のサブフレーム期間において、赤色（Ｒ）が表示されると、連続する２つのサブフレーム期間に着目する限り、三原色の混色により白色が表現される。 Here, cyan can be assigned as appropriate, but as shown in FIG. 5, it is extremely preferable to assign red after cyan as the color reproducibility becomes higher. That is, since cyan (C) is expressed by a mixed color of green (G) and blue (B), when red (R) is displayed in the immediately following subframe period, two consecutive subframe periods are displayed. As long as attention is focused on, white is expressed by a mixture of the three primary colors.
　例えば、シアン色の階調値が２５５であり、赤色の階調値が０である画像を表示する場合、液晶パネルの透過率が第２のサブフレーム期間において１００％から瞬時に０％になることはなく、液晶パネルの透過率が本来の０％になるまでの間に、液晶パネルに遮られるべきバックライトからの赤色の混色光の一部が透過する。しかし、第１および第２のサブフレーム期間に着目するとき、この連続する期間内では、白色を含む画像が表示されることになる。この結果、視聴者は、白色が混色したシアン色の画像を見ることになる。しかし、白色は無彩色であるため、混色により色バランスを大きく崩すことがない。その白色の輝度が小さければ、混色による色バランスの崩れは、より小さくなる。したがって、シアン色の画像は、大きく色バランスを崩すことなく表示される。このことにより、装置の色再現性が向上し、表示品質が上がる。 For example, when displaying an image having a cyan gradation value of 255 and a red gradation value of 0, the transmittance of the liquid crystal panel is instantaneously changed from 100% to 0% in the second subframe period. In the meantime, a part of the red mixed color light from the backlight to be blocked by the liquid crystal panel is transmitted until the transmittance of the liquid crystal panel reaches the original 0%. However, when attention is paid to the first and second subframe periods, an image including white is displayed within the continuous period. As a result, the viewer sees a cyan image in which white is mixed. However, since white is an achromatic color, the color balance is not greatly lost due to color mixing. If the brightness of the white color is small, the color balance collapse due to the mixed color becomes smaller. Therefore, the cyan image is displayed without greatly losing the color balance. This improves the color reproducibility of the device and improves the display quality.
　続く第２から第４までのサブフレーム期間における装置各部の動作は、第１の実施形態の場合と同様であるため、説明を省略する。 Since the operation of each unit in the subsequent second to fourth subframe periods is the same as that in the first embodiment, description thereof is omitted.
　さらに第５および第６のサブフレーム期間は、第１の実施形態における第４および第５のサブフレーム期間の場合と同様であるので、説明を省略する。なお、本実施形態では、シアン色を例にして説明したが、これに代えてマゼンタ色（Ｍ）を使用してもよい。以下、図６を参照して説明する。 Further, since the fifth and sixth subframe periods are the same as those in the fourth and fifth subframe periods in the first embodiment, the description thereof is omitted. In this embodiment, the cyan color is described as an example, but a magenta color (M) may be used instead. Hereinafter, a description will be given with reference to FIG.
　図６は、本実施形態の各サブフレーム期間における表示色とその点灯期間とを別例を示す図である。図６に示されるように、図５と同様に１フレーム期間は、第１から第６までの６つのサブフレーム期間に分割されているが、シアン色に代えてマゼンタ色が使用され、その割り当て位置も異なっている。 FIG. 6 is a diagram showing another example of the display color and its lighting period in each subframe period of the present embodiment. As shown in FIG. 6, as in FIG. 5, one frame period is divided into six subframe periods from 1st to 6th, but magenta is used instead of cyan, and its allocation The position is also different.
　すなわち、第２のサブフレーム期間の前半には、各画素形成部３０は補正映像信号ＣＶのマゼンタ色を示す階調値に基づいて駆動され、その後半には赤色ＬＥＤ２０ｒおよび青色ＬＥＤ２０ｂが発光する。なお、赤色ＬＥＤ２０ｒおよび青色ＬＥＤ２０ｂが発光する構成に替えて、新たに設けられるマゼンタ色ＬＥＤが発光する構成であってもよい。 That is, in the first half of the second subframe period, each pixel forming unit 30 is driven based on the gradation value indicating the magenta color of the corrected video signal CV, and the red LED 20r and the blue LED 20b emit light in the latter half. Instead of the configuration in which the red LED 20r and the blue LED 20b emit light, a newly provided magenta LED may emit light.
　ここで、マゼンタ色の割り当ては適宜に行うことができるが、図６に示すように、マゼンタ色の後に緑色を割り当てると色再現性がより高くなるため極めて好ましい。すなわち、マゼンタ色（Ｍ）は赤色（Ｒ）と青色（Ｂ）との混色より表現されるため、直後のサブフレーム期間において、緑色（Ｇ）が表示されると、連続する２つのサブフレーム期間に着目する限り、三原色の混色により白色が表現される。 Here, magenta color assignment can be performed as appropriate, but as shown in FIG. 6, it is extremely preferable to assign green color after magenta color because the color reproducibility becomes higher. That is, since the magenta color (M) is expressed by a mixed color of red (R) and blue (B), when green (G) is displayed in the immediately following subframe period, two consecutive subframe periods As long as attention is focused on, white is expressed by a mixture of the three primary colors.
　すなわち、第２および第３のサブフレーム期間に着目するとき、この連続する期間内では、白色の画像が表示されることになる。この結果、視聴者は、白色が混色したマゼンタ色の画像を見ることになる。しかし、白色は無彩色であるため、混色により色バランスを大きく崩すことがない。その白色の輝度が小さければ、混色による色バランスの崩れは、より小さくなる。したがって、マゼンタ色の画像は、大きく色バランスを崩すことなく表示される。このことにより、装置の色再現性が向上し、表示品質が上がる。 That is, when paying attention to the second and third subframe periods, a white image is displayed within this continuous period. As a result, the viewer sees a magenta image in which white is mixed. However, since white is an achromatic color, the color balance is not greatly lost due to color mixing. If the brightness of the white color is small, the color balance collapse due to the mixed color becomes smaller. Therefore, the magenta image is displayed without greatly losing the color balance. This improves the color reproducibility of the device and improves the display quality.
　また第４のサブフレーム期間に青色が割り当てられると、より視感効率の高いシアン色の色再現性を高めるために好ましいことは前述したとおりである。したがって、第１のサブフレーム期間には赤色が割り当てられることになる。 Also, as described above, it is preferable that blue is assigned in the fourth subframe period in order to improve the color reproducibility of cyan with higher luminous efficiency. Therefore, red is assigned in the first subframe period.
　さらに、第５のサブフレーム期間に割り当てられる表示色は、黄色（Ｙ）であり、第６のサブフレーム期間に割り当てられる表示色は、白色（Ｗ）であるが、このように黄色を表示した直後に白色を表示するという表示順序が本発明に特有の構成の一つとなっている。このことは第１の実施形態と同様であり、同様にこの順序は固定されていなければならない。 Further, the display color assigned to the fifth subframe period is yellow (Y), and the display color assigned to the sixth subframe period is white (W). Thus, yellow is displayed. A display order in which white is displayed immediately after is one of the configurations unique to the present invention. This is the same as in the first embodiment, and this order must be fixed as well.
＜２．３　第２の実施形態の効果＞
　以上のように、本実施形態における液晶表示装置１０は、第１の実施形態に記載したと同様の理由により、６つの表示色（ＣＲＧＢＹＷまたはＲＭＧＢＹＷ）の各サブフレーム期間への割り当ての順序（色順序）を固定することにより色割れやフリッカの発生を防止し、かつ黄色を割り当てたサブフレーム期間の直後のサブフレーム期間に白色を割り当てることにより、色再現性の低下を抑制することができる。また、第１の実施形態の場合よりも（シアン色またはマゼンタ色のいずれかを追加することにより）表示色が多くなるため、色表現性を向上させることができる。なお、この色表現性は、色再現性とも呼ばれるが、多色表示による広域の色再現性をここでは色表現性と呼び、本来表示したい色からのずれが抑制された色の忠実な再現性をここでは色再現性と呼ぶものとする。 <2.3 Effects of Second Embodiment>
As described above, the liquid crystal display device 10 according to the present embodiment is arranged in the order (colors) of allocation of the six display colors (CRGBYW or RMGBYW) to each subframe period for the same reason as described in the first embodiment. By fixing the (order), it is possible to prevent the occurrence of color breakup and flicker, and by assigning white to the subframe period immediately after the subframe period to which yellow is assigned, it is possible to suppress a decrease in color reproducibility. In addition, since the number of display colors is increased (by adding either cyan or magenta color) as compared with the first embodiment, color expression can be improved. This color reproducibility is also called color reproducibility. Wide color reproducibility by multicolor display is referred to here as color reproducibility, and faithful reproducibility of colors with suppressed deviation from the original color to be displayed. Is referred to herein as color reproducibility.
　さらに、シアン色を割り当てる場合には、シアン色、赤色の順番で連続する２つのサブフレーム期間に割り当て、マゼンタ色を割り当てる場合には、マゼンタ色、緑色の順番で連続する２つのサブフレーム期間に割り当てれば、さらにシアン色またはマゼンタ色の色再現性を高めることができる。 Further, when assigning cyan color, it is assigned to two consecutive subframe periods in the order of cyan and red, and when assigning magenta color, it is assigned to two consecutive subframe periods in the order of magenta and green. If assigned, the color reproducibility of cyan or magenta can be further improved.
＜３．　第３の実施形態＞
＜３．１　液晶表示装置の構成＞
　本発明の第３の実施形態に係るフィールドシーケンシャル方式の液晶表示装置の全体構成は、第１の実施形態の場合と同様であり（図１を参照）、１フレーム期間を７つのサブフレーム期間に分割する点を除き、同様の動作を行うので、その説明を省略する。 <3. Third Embodiment>
<Configuration of liquid crystal display device>
The entire configuration of the field sequential type liquid crystal display device according to the third embodiment of the present invention is the same as that of the first embodiment (see FIG. 1), and one frame period is divided into seven subframe periods. Since the same operation is performed except for the division, the description thereof is omitted.
　本実施形態における液晶表示装置は、７つのサブフレーム期間を使用する点で、第１の実施形態の場合と、表示制御回路１６の動作が一部異なる。すなわち、表示制御回路１６は、赤色（Ｒ）、緑色（Ｇ）、および青色（Ｂ）の各階調値を表す入力信号ＤＶに基づき、シアン色（Ｃ）、マゼンタ色（Ｍ）、黄色（Ｙ）、および白色（Ｗ）の各階調値を加え、さらに補正された赤色、緑色、および青色の各階調値の合計７種類の色の階調値を表す補正映像信号ＣＶを出力する。なお、３つの原色（ＲＧＢ）からなる或る画素の入力階調値から、７つの表示色（ＲＧＢＣＭＹＷ）からなる或る画素の表示階調値を算出する方法は、第１の実施形態と同様に周知であるため説明を省略する。 The liquid crystal display device in this embodiment is partially different in operation of the display control circuit 16 from the first embodiment in that it uses seven subframe periods. That is, the display control circuit 16 performs cyan (C), magenta (M), and yellow (Y) based on the input signal DV representing the gradation values of red (R), green (G), and blue (B). ) And white (W) gradation values are added, and a corrected video signal CV representing gradation values of a total of seven types of corrected red, green, and blue gradation values is output. Note that the method for calculating the display gradation value of a certain pixel composed of seven display colors (RGBCMYW) from the input gradation value of a certain pixel composed of three primary colors (RGB) is the same as in the first embodiment. The description is omitted because it is well known.
　本実施形態における液晶表示装置１０は、１フレーム期間を第１から第７までのサブフレーム期間に分割し、各サブフレーム期間に割り当てられる表示色を図７に示す順番で表示する。以下、図７を参照して、各サブフレーム期間における表示について説明する。 The liquid crystal display device 10 according to the present embodiment divides one frame period into first to seventh subframe periods, and displays the display colors assigned to the subframe periods in the order shown in FIG. Hereinafter, display in each subframe period will be described with reference to FIG.
＜３．２　各サブフレーム期間における表示＞
　図７は、本実施形態の各サブフレーム期間における表示色とその点灯期間とを示す図である。図７に示されるように、１フレーム期間は、第１から第７までの７つのサブフレーム期間に分割されており、各サブフレーム期間の前半は、非点灯期間であり、後半が点灯期間である。この点は、図２に示す場合と同様である。 <3.2 Display in each subframe period>
FIG. 7 is a diagram showing display colors and their lighting periods in each subframe period of the present embodiment. As shown in FIG. 7, one frame period is divided into seven subframe periods from first to seventh, and the first half of each subframe period is a non-lighting period and the second half is a lighting period. is there. This is the same as the case shown in FIG.
　また本実施形態は、第２の実施形態において、いずれか一方が択一的に割り当てられていたシアン色およびマゼンタ色を共に割り当てる構成となっている。すなわち、第１のサブフレーム期間に割り当てられる表示色は、シアン色（Ｃ）であり、第２のサブフレーム期間に割り当てられる表示色は、赤色（Ｒ）である。さらに、第３のサブフレーム期間に割り当てられる表示色は、マゼンタ色（Ｍ）であり、第４のサブフレーム期間に割り当てられる表示色は、緑色（Ｇ）である。なお、第１および第２のサブフレーム期間と、第３および第４のサブフレーム期間とを入れ替えることも可能ではあるが、視感効率の高いシアン色の色再現性を重視する観点からは、本実施形態に示す順番で割り当てることが好ましい。 Also, the present embodiment is configured to assign both the cyan color and the magenta color, which are alternatively assigned in the second embodiment. That is, the display color assigned to the first subframe period is cyan (C), and the display color assigned to the second subframe period is red (R). Further, the display color assigned to the third subframe period is magenta (M), and the display color assigned to the fourth subframe period is green (G). Although it is possible to interchange the first and second subframe periods and the third and fourth subframe periods, from the viewpoint of emphasizing color reproducibility of cyan with high luminous efficiency, It is preferable to assign in the order shown in this embodiment.
　さらに本実施形態では、第６のサブフレーム期間に割り当てられる表示色は、黄色（Ｙ）であり、第７のサブフレーム期間に割り当てられる表示色は、白色（Ｗ）であるが、このように黄色を表示した直後に白色を表示するという表示順序が本発明に特有の構成の一つとなっている。このことは第１の実施形態と同様であり、同様にこの順序は固定されていなければならない。この特徴的な構成によって、第１の実施形態と同様に黄色系の色再現性が向上し、表示品質を上げることができる。 Furthermore, in this embodiment, the display color assigned to the sixth subframe period is yellow (Y), and the display color assigned to the seventh subframe period is white (W). The display order in which white is displayed immediately after displaying yellow is one of the configurations unique to the present invention. This is the same as in the first embodiment, and this order must be fixed as well. With this characteristic configuration, yellow color reproducibility can be improved and display quality can be improved as in the first embodiment.
　もっとも、黄色を表示する前に、赤色、青色、緑色、マゼンタ色、およびシアン色のいずれが表示されていてもよいし、黄色が第１のサブフレーム期間において表示される構成であってもよい。また、白色を表示した後に赤色、青色、緑色、マゼンタ色、およびシアン色のいずれが表示されてもよい。 However, before displaying yellow, any of red, blue, green, magenta, and cyan may be displayed, or yellow may be displayed in the first subframe period. . Further, after displaying white, any of red, blue, green, magenta, and cyan may be displayed.
＜３．３　第３の実施形態の効果＞
　以上のように、本実施形態における液晶表示装置１０は、第１の実施形態に記載したと同様の理由により、７つの表示色（ＣＲＭＧＢＹＷ）の各サブフレーム期間への割り当ての順序（色順序）を固定することにより色割れやフリッカの発生を防止し、かつ黄色を割り当てたサブフレーム期間の直後のサブフレーム期間に白色を割り当てることにより、色再現性の低下を抑制することができる。また、第２の実施形態の場合よりも（シアン色およびマゼンタ色の双方を使用することにより）表示色が多くなるため、さらに色再現性を向上させることができる。 <3.3 Effects of Third Embodiment>
As described above, the liquid crystal display device 10 according to the present embodiment assigns seven display colors (CRMGBBYW) to each subframe period (color order) for the same reason as described in the first embodiment. By fixing, white color is assigned to the subframe period immediately after the subframe period to which yellow is assigned, and the deterioration of color reproducibility can be suppressed. In addition, since the number of display colors is increased (by using both cyan and magenta colors) as compared with the second embodiment, color reproducibility can be further improved.
＜４．　第４の実施形態＞
＜４．１　液晶表示装置の構成＞
　本発明の第４の実施形態に係るフィールドシーケンシャル方式の液晶表示装置の全体構成は、第１の実施形態の場合と同様であり（図１を参照）、各色の割り当ての順番を除き、同様の動作を行うので、その説明を省略する。 <4. Fourth Embodiment>
<4.1 Configuration of liquid crystal display device>
The overall configuration of the field sequential type liquid crystal display device according to the fourth embodiment of the present invention is the same as that of the first embodiment (see FIG. 1), and the same configuration except for the order of allocation of each color. Since the operation is performed, the description thereof is omitted.
　本実施形態における液晶表示装置１０は、１フレーム期間を第１から第５までのサブフレーム期間に分割し、各サブフレーム期間に割り当てられる表示色を図８に示す順番で表示する。以下、図８を参照して、各サブフレーム期間における表示について説明する。 The liquid crystal display device 10 according to this embodiment divides one frame period into first to fifth subframe periods, and displays the display colors assigned to the subframe periods in the order shown in FIG. Hereinafter, display in each subframe period will be described with reference to FIG.
＜４．２　各サブフレーム期間における表示＞
　図８は、本実施形態の各サブフレーム期間における表示色とその点灯期間とを示す図である。図８に示されるように、１フレーム期間は、第１から第５までの５つのサブフレーム期間に分割されており、各サブフレーム期間の前半は、非点灯期間であり、後半が点灯期間である。この点は、図２に示す場合と同様である。 <Display in each subframe period>
FIG. 8 is a diagram showing display colors and their lighting periods in each subframe period of the present embodiment. As shown in FIG. 8, one frame period is divided into five subframe periods from first to fifth. The first half of each subframe period is a non-lighting period and the second half is a lighting period. is there. This is the same as the case shown in FIG.
　ここで本実施形態では、第４のサブフレーム期間に割り当てられる表示色は、黄色（Ｙ）である点は第１の実施形態と同一であるが、第５のサブフレーム期間に割り当てられる表示色は、青色（Ｂ）であり、このように黄色を表示した直後に青色を表示するという表示順序が本発明に特有の構成の一つとなっている。この点、第１の実施形態と全く異なっているが、第１の実施形態の場合と同様にこの順序は固定されていなければならない。この特徴的な構成によって、第１の実施形態と同様に黄色系の色再現性が向上し、表示品質を上げることができる。 Here, in this embodiment, the display color assigned to the fourth subframe period is the same as that of the first embodiment in that it is yellow (Y), but the display color assigned to the fifth subframe period is the same. Is blue (B), and the display order of displaying blue immediately after displaying yellow in this way is one of the structures unique to the present invention. Although this point is completely different from the first embodiment, this order must be fixed as in the case of the first embodiment. With this characteristic configuration, yellow color reproducibility can be improved and display quality can be improved as in the first embodiment.
　本実施形態では、図５に示したシアン色の後に赤色を割り当てると色再現性がより高くなるのと同様に、図８に示す黄色の後に青色を割り当てると色再現性がより高くなる。すなわち、黄色（Ｙ）は赤色（Ｒ）と緑色（Ｇ）との混色より表現されるため、直後のサブフレーム期間において、青色（Ｂ）が表示されると、連続する２つのサブフレーム期間に着目する限り、三原色の混色により白色が表現される。 In the present embodiment, the color reproducibility becomes higher when the red color is assigned after the cyan color shown in FIG. 5 and the color reproducibility becomes higher when the blue color is assigned after the yellow color shown in FIG. That is, since yellow (Y) is expressed by a mixed color of red (R) and green (G), when blue (B) is displayed in the immediately following subframe period, two consecutive subframe periods are displayed. As long as attention is paid, white is expressed by a mixture of the three primary colors.
　例えば、黄色の階調値が２５５であり、青色の階調値が０である画像を表示する場合、液晶パネルの透過率が第２のサブフレーム期間において１００％から瞬時に０％になることはなく、液晶パネルの透過率が本来の０％になるまでの間に、液晶パネルに遮られるべきバックライトからの青色の混色光の一部が透過する。しかし、第１および第２のサブフレーム期間に着目するとき、この連続する期間内では、白色を含む画像が表示されることになる。この結果、視聴者は、白色が混色した黄色の画像を見ることになる。しかし、白色は無彩色であるため、混色により色バランスを大きく崩すことがない。その白色の輝度が小さければ、混色による色バランスの崩れは、より小さくなる。したがって、黄色の画像は、大きく色バランスを崩すことなく表示される。このことにより、装置の色再現性、特に視感効率の高い黄色の色再現性が向上し、表示品質が上がる。 For example, when an image with a yellow gradation value of 255 and a blue gradation value of 0 is displayed, the transmittance of the liquid crystal panel is instantaneously changed from 100% to 0% in the second subframe period. No part of the blue mixed color light from the backlight to be blocked by the liquid crystal panel is transmitted until the transmittance of the liquid crystal panel reaches 0%. However, when attention is paid to the first and second subframe periods, an image including white is displayed within the continuous period. As a result, the viewer sees a yellow image in which white is mixed. However, since white is an achromatic color, the color balance is not greatly lost due to color mixing. If the brightness of the white color is small, the color balance collapse due to the mixed color becomes smaller. Therefore, the yellow image is displayed without greatly losing the color balance. As a result, the color reproducibility of the apparatus, particularly the yellow color reproducibility with high luminous efficiency, is improved, and the display quality is improved.
　また、本実施形態では、第１のサブフレーム期間に割り当てられる表示色は、白色（Ｗ）となっているが、この割り当て順には限定されない。もっとも、或るフレーム期間における最後のサブフレーム期間は、次のフレーム期間における最初のサブフレーム期間と連続しているため、第５のサブフレーム期間に青色を割り当てる本実施形態の構成では、第１のサブフレーム期間に赤色または緑色を割り当てることは好ましくない。そこで、本実施形態のように、白色を割り当てることにより、色再現性を向上させることができる。 In this embodiment, the display color assigned to the first subframe period is white (W), but the order of assignment is not limited. However, since the last subframe period in a certain frame period is continuous with the first subframe period in the next frame period, in the configuration of the present embodiment in which blue is assigned to the fifth subframe period, It is not preferable to assign red or green to each subframe period. Therefore, color reproducibility can be improved by assigning white as in this embodiment.
　さらに、本実施形態では、５つの表示色（ＷＲＧＹＢ）が割り当てられる構成であるが、第２または第３の実施形態におけるように、６つ以上の表示色が割り当てられる構成であっても良い。この場合にも、上記と同様、黄色を割り当てたサブフレーム期間の直後のサブフレーム期間に青色を割り当てる特徴的な構成により、色再現性を向上させることができる。なお、上記場合には、黄色を表示する前に、赤色、青色、緑色、マゼンタ色、およびシアン色のいずれが表示されていてもよいし、黄色が第１のサブフレーム期間において表示される構成であってもよい。また、青色を表示した後に赤色、緑色、白色、マゼンタ色、およびシアン色のいずれが表示されてもよい。 Furthermore, in the present embodiment, five display colors (WRGYB) are assigned. However, as in the second or third embodiment, six or more display colors may be assigned. Also in this case, as described above, the color reproducibility can be improved by the characteristic configuration in which blue is assigned to the subframe period immediately after the subframe period to which yellow is assigned. In the above case, any of red, blue, green, magenta, and cyan may be displayed before yellow is displayed, and yellow is displayed in the first subframe period. It may be. Further, after displaying blue, any of red, green, white, magenta, and cyan may be displayed.
＜４．３　第４の実施形態の効果＞
　以上のように、本実施形態における液晶表示装置１０は、第１の実施形態に記載したと同様の理由により、５つの表示色（ＷＲＧＹＢ）の各サブフレーム期間への割り当ての順序（色順序）を固定することにより色割れやフリッカの発生を防止し、かつ黄色を割り当てたサブフレーム期間の直後のサブフレーム期間に青色を割り当てることにより、色再現性の低下を抑制することができる。 <4.3 Effects of Fourth Embodiment>
As described above, in the liquid crystal display device 10 according to the present embodiment, the order in which the five display colors (WRGYB) are assigned to each subframe period (color order) for the same reason as described in the first embodiment. By fixing, the occurrence of color breakup and flicker can be prevented, and by assigning blue to the subframe period immediately after the subframe period to which yellow is assigned, deterioration in color reproducibility can be suppressed.
＜５．　その他の変形例＞
　上記各実施形態では、液晶表示装置を例に説明したが、フィールドシーケンシャル方式を使用した表示装置であれば、必ずしも液晶が使われる必要はなく、液晶に代わる周知のシャッター素子が使用される構成であってもよい。ただし液晶の場合と同様に、或るサブフレーム期間における階調が次のサブフレーム期間の階調に影響を与えるような応答特性を有していることが本発明を適用するためには好適である。 <5. Other variations>
In each of the above embodiments, the liquid crystal display device has been described as an example. However, in the case of a display device using a field sequential method, the liquid crystal is not necessarily used, and a known shutter element that replaces the liquid crystal is used. There may be. However, as in the case of the liquid crystal, it is preferable for applying the present invention that the gradation in one subframe period has a response characteristic that affects the gradation in the next subframe period. is there.
　上記各実施形態では、黄色および白色のほか、３色から５色までの色を使用する構成であるが、黄色を表示した直後に白色または青色を表示するという本発明に特有の構成が含まれていれば、上記色の数および種類には限定されない。その他、上記各実施形態には種々の変形を施すことが可能である。 In each of the above embodiments, in addition to yellow and white, a configuration using three to five colors is included. However, a configuration unique to the present invention in which white or blue is displayed immediately after displaying yellow is included. If so, the number and type of the colors are not limited. In addition, various modifications can be made to the above embodiments.
　本発明は、カラー表示装置に適用されるものであって、特にフィールドシーケンシャル方式でカラー表示を行う液晶表示装置などの表示装置に適している。 The present invention is applied to a color display device, and is particularly suitable for a display device such as a liquid crystal display device that performs color display by a field sequential method.
　１０…液晶表示装置
　１１…液晶パネル
　１３…バックライト制御回路
　１６…表示制御回路
　１７…走査信号線駆動回路
　１８…映像信号線駆動回路
　２０…バックライトユニット
　２１…スイッチ群
　Ｃ１～Ｃ４…制御信号
　ＢＣ…バックライト制御信号
　Ｇ１～Ｇｎ…走査信号線
　Ｓ１～Ｓｍ…映像信号線
　ＤＶ…映像信号
　ＣＶ…補正映像信号 DESCRIPTION OF SYMBOLS 10 ... Liquid crystal display device 11 ... Liquid crystal panel 13 ... Backlight control circuit 16 ... Display control circuit 17 ... Scanning signal line drive circuit 18 ... Video signal line drive circuit 20 ... Backlight unit 21 ... Switch group C1-C4 ... Control signal BC ... Backlight control signals G1 to Gn ... Scanning signal lines S1 to Sm ... Video signal lines DV ... Video signals CV ... Correction video signals

Claims (8)

  1. 　１フレーム期間を複数のサブフレーム期間に分割し、サブフレーム期間毎に異なる色の画像を表示する表示装置であって、
    　マトリクス状に配置された複数の画素形成部を含む表示パネルと、
    　入力信号に基づいて、前記サブフレーム期間毎に前記複数の画素形成部の光の透過率を制御する補正映像信号を出力する表示制御回路と、
    　前記補正映像信号に基づいて前記複数の画素形成部を駆動する駆動回路とを備え、
    　前記表示制御回路は、前記サブフレーム期間のうちの１つで前記表示パネルに黄色の画像が表示され、当該黄色の画像が表示されるサブフレーム期間の直後のサブフレーム期間で前記表示パネルに白色または青色の画像が表示されるよう、前記異なる色を前記複数のサブフレーム期間に割り当てた前記補正映像信号を出力することを特徴とする、表示装置。     A display device that divides one frame period into a plurality of subframe periods and displays an image of a different color for each subframe period,
    A display panel including a plurality of pixel formation portions arranged in a matrix;
    A display control circuit that outputs a corrected video signal for controlling the light transmittance of the plurality of pixel forming units for each subframe period based on an input signal;
    A drive circuit that drives the plurality of pixel forming units based on the corrected video signal,
    The display control circuit displays a yellow image on the display panel in one of the subframe periods, and displays white on the display panel in a subframe period immediately after the subframe period in which the yellow image is displayed. Alternatively, the display device outputs the corrected video signal in which the different colors are assigned to the plurality of subframe periods so that a blue image is displayed.
  2. 　前記表示制御回路は、赤色、緑色、および青色を所定の順番で前記複数のサブフレーム期間に割り当てることを特徴とする、請求項１に記載の表示装置。 The display device according to claim 1, wherein the display control circuit assigns red, green, and blue to the plurality of subframe periods in a predetermined order.
  3. 　前記表示制御回路は、前記直後のサブフレーム期間で白色の画像が表示される場合、赤色、緑色、および青色を前記複数のサブフレーム期間のうちの連続する３つに割り当てることを特徴とする、請求項２に記載の表示装置。 The display control circuit assigns red, green, and blue colors to three consecutive subframe periods when a white image is displayed in the immediately following subframe period. The display device according to claim 2.
  4. 　前記表示制御回路は、前記直後のサブフレーム期間で青色の画像が表示される場合、緑色および赤色をその順番で前記複数のサブフレーム期間のうちの連続する２つに割り当てることを特徴とする、請求項２に記載の表示装置。 The display control circuit assigns green and red to two consecutive subframe periods in that order when a blue image is displayed in the immediately following subframe period, The display device according to claim 2.
  5. 　前記表示制御回路は、シアン色およびマゼンタ色の少なくとも一方を前記複数のサブフレーム期間に割り当てることを特徴とする、請求項２に記載の表示装置。 The display device according to claim 2, wherein the display control circuit assigns at least one of cyan and magenta colors to the plurality of subframe periods.
  6. 　前記表示制御回路は、
    　　シアン色を割り当てる場合には、シアン色および赤色をその順番で前記複数のサブフレーム期間のうちの連続する２つに割り当て、
    　　マゼンタ色を割り当てる場合には、マゼンタ色および緑色をその順番で前記複数のサブフレーム期間のうちの連続する２つに割り当てることを特徴とする、請求項５に記載の表示装置。     The display control circuit includes:
    When assigning cyan, assign cyan and red in that order to two consecutive subframe periods,
    6. The display device according to claim 5, wherein when assigning a magenta color, a magenta color and a green color are assigned to two consecutive subframe periods in that order.
  7. 　前記画素形成部は、光の透過率を制御される液晶素子を含むことを特徴とする、請求項１に記載の表示装置。 The display device according to claim 1, wherein the pixel formation unit includes a liquid crystal element whose light transmittance is controlled.
  8. 　マトリクス状に配置された複数の画素形成部を含む表示パネルに、１フレーム期間を複数のサブフレーム期間に分割し、サブフレーム期間毎に異なる色の画像を表示する表示方法であって、
    　入力信号に基づいて、前記サブフレーム期間毎に前記複数の画素形成部の光の透過率を制御する補正映像信号を出力する表示制御ステップと、
    　前記補正映像信号に基づいて前記複数の画素形成部を駆動する駆動ステップとを備え、
    　前記表示制御ステップでは、前記サブフレーム期間のうちの１つで前記表示パネルに黄色の画像が表示され、当該黄色の画像が表示されるサブフレーム期間の直後のサブフレーム期間で前記表示パネルに白色または青色の画像が表示されるよう、前記異なる色を前記複数のサブフレーム期間に割り当てた前記補正映像信号を出力することを特徴とする、表示方法。     A display method that divides one frame period into a plurality of subframe periods on a display panel including a plurality of pixel formation portions arranged in a matrix, and displays images of different colors for each subframe period,
    A display control step of outputting a corrected video signal for controlling the light transmittance of the plurality of pixel forming units for each subframe period based on an input signal;
    A driving step of driving the plurality of pixel forming units based on the corrected video signal,
    In the display control step, a yellow image is displayed on the display panel in one of the subframe periods, and a white color is displayed on the display panel in a subframe period immediately after the subframe period in which the yellow image is displayed. Alternatively, the display method includes outputting the corrected video signal in which the different colors are assigned to the plurality of subframe periods so that a blue image is displayed.
PCT/JP2014/073878 2013-12-18 2014-09-10 Display device WO2015093111A1 (en)

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Citations (7)

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JP2003241714A (en) * 2001-12-13 2003-08-29 Matsushita Electric Ind Co Ltd Method for driving display device, and display device
JP2003280614A (en) * 2002-03-27 2003-10-02 Matsushita Electric Ind Co Ltd Color sequential display type liquid crystal display device and driving method thereof
FR2887673A1 (en) * 2005-06-24 2006-12-29 Thomson Licensing Sa Imager e.g. micro-display, illuminating method for e.g. overhead projector, involves setting beam having sequences of monochrome illumination sub-beams, where each sequence has three pairs of colors having complementary characteristics
JP2007114480A (en) * 2005-10-20 2007-05-10 Toshiba Matsushita Display Technology Co Ltd Liquid crystal display device
JP2009036951A (en) * 2007-08-01 2009-02-19 Seiko Epson Corp Display device, method of driving display device and electronic apparatus
WO2009044909A1 (en) * 2007-10-04 2009-04-09 Nec Display Solutions, Ltd. Video display device and light source driving method thereof
US20110304659A1 (en) * 2010-06-15 2011-12-15 Acer Incorporated Dlp projector and color compensation method of bulb of dlp projector

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003241714A (en) * 2001-12-13 2003-08-29 Matsushita Electric Ind Co Ltd Method for driving display device, and display device
JP2003280614A (en) * 2002-03-27 2003-10-02 Matsushita Electric Ind Co Ltd Color sequential display type liquid crystal display device and driving method thereof
FR2887673A1 (en) * 2005-06-24 2006-12-29 Thomson Licensing Sa Imager e.g. micro-display, illuminating method for e.g. overhead projector, involves setting beam having sequences of monochrome illumination sub-beams, where each sequence has three pairs of colors having complementary characteristics
JP2007114480A (en) * 2005-10-20 2007-05-10 Toshiba Matsushita Display Technology Co Ltd Liquid crystal display device
JP2009036951A (en) * 2007-08-01 2009-02-19 Seiko Epson Corp Display device, method of driving display device and electronic apparatus
WO2009044909A1 (en) * 2007-10-04 2009-04-09 Nec Display Solutions, Ltd. Video display device and light source driving method thereof
US20110304659A1 (en) * 2010-06-15 2011-12-15 Acer Incorporated Dlp projector and color compensation method of bulb of dlp projector

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