JP2009053475A - Display device, display device driving method, and electronic apparatus - Google Patents

Abstract

To suppress color breakup and flicker under a field sequential method.
An image processing circuit 20 separates a separated image signal S2 for designating gradation for each pixel of a white component and a plurality of color components from an input image signal S1 for designating gradations of a plurality of primary color components for each pixel. Is generated. In each of the plurality of subfields SF in one frame F, the control circuit 30 causes the display body 10 to display a single color image of the white component and each of the plurality of color components based on the separated image signal S2. The subfield SF on which the white component single color image is displayed is located before or after the start of the plurality of subfields on which the plurality of color component single color images are displayed. In a frame in which the display of a white image is specified, the display brightness of the white component single-color image is lower than the display brightness of each color component single-color image.
[Selection] Figure 1

Description

  The present invention relates to a technique for displaying a color image by a field sequential method.

In a hold-type display device (for example, a liquid crystal device) in which display of an image is maintained within a frame, a phenomenon that an outline of an element moving in a moving image becomes unclear so as to draw a tail (also called “tailing”) Is hereinafter referred to as “moving image blur”). On the other hand, moving image blur is reduced by intermittently displaying images, but there is a problem that blinking of images is perceived as flicker. In order to improve both moving image blur and flicker, for example, Non-Patent Document 1 reduces moving image blur by displaying a high-luminance image in the center period in the frame, and before and after the period. A technique for suppressing flicker by maintaining light emission even during a period is disclosed.
Hiroshi Ito et al., “Examination of video image quality improvement method of AMLCD”, The Institute of Image Information and Television Engineers Technical Report, March 22, 2004, Vol.28 No.22 p.13-p.16

  By the way, a display device of a field sequential method (a surface sequential method and a color sequential method) that allows a viewer to perceive a color image by sequentially displaying a single color image of a plurality of colors (for example, red, green, and blue) constituting a color image. Has been proposed. In the field sequential method, since a single color image of each color is displayed for each subfield, a phenomenon in which each color component is separated and perceived in the vicinity of the outline of the moving element in the moving image (hereinafter referred to as “color breakup”). ) Occurs. Further, flicker is also a problem due to the operation of sequentially displaying a plurality of single color images for each subfield. In view of the above circumstances, an object of the present invention is to solve the problem of suppressing both color breakup and flicker under a field sequential method.

  In order to solve the above-described problems, a display device according to the present invention includes a white component and a plurality of components from a display body in which a plurality of pixels are arranged, and an input image signal that specifies gradations of a plurality of primary color components for each pixel. Separating means (for example, the image processing circuit 20 in FIG. 1) for generating a separated image signal for designating gradation for each pixel with respect to color components, and before or after the start of a plurality of subfields for displaying single color images of the respective color components Control means for sequentially displaying each monochrome image on the display body based on the separated image signal in each of the plurality of subfields in one frame so that the monochrome image of the white component is displayed in the subfield of In addition, in a frame in which the display of a white image is specified, the display brightness of the white component single color image is lower than the display brightness of the single color image of each color component. The display body includes, for example, a liquid crystal device in which an OCB mode liquid crystal is sealed in a gap between a pair of substrates. The display device of the present invention is used in various electronic devices.

  According to the above configuration, since the monochromatic image of the white component is displayed in the subfield before or after the start of the plurality of subfields displaying the monochromatic image of each color component, the color breakup and flicker perceived by the observer are displayed. Can be suppressed.

  In a preferred aspect of the present invention, the separating unit generates a separated image signal that specifies gradations for the plurality of color components, the first white component, and the second white component, and the control unit generates a single-color image of each color component. The first white component monochromatic image is displayed on the display body in the subfield before the start of the plurality of subfields to be displayed, and the second subfield after the end of the plurality of subfields in which the monochromatic image of each color component is displayed. In a frame in which a white color monochromatic image is displayed on the display body and display of the white color image is designated, the display luminance of each monochromatic image of the first white color component and the second white color component is the display luminance of the monochromatic image of each color component. Lower than. According to the above aspect, since the monochromatic image of the white component is displayed before and after the start of the plurality of subfields in which the monochromatic image of each color component is displayed, either before or after the monochromatic image of each color component is displayed. It is possible to effectively reduce color breakup compared to a configuration that displays a monochromatic image of a white component in only one of them.

  In a preferred aspect of the present invention, the total amount of light used for displaying a white component monochromatic image in a frame in which display of a white image is designated is a single color of the white component and each of the plurality of color components in the frame. It is 30% or more and 40% or less of the total light amount used for displaying an image. According to the above aspect, both color breakup and flicker are effectively suppressed.

  In a preferred aspect of the present invention, the separation unit extracts a separation component (for example, the Ga component in FIG. 6) for a specific color from the plurality of color components, and the control unit displays a plurality of sub-colors that display a single color image of each color component. A monochromatic image of the separation component is displayed on the display device in a subfield before or after the start of the field. According to the above aspect, since a single color image of a specific color is dispersively displayed in a plurality of subfields, for example, flicker can be effectively suppressed when displaying an image whose entire area is set to a specific color. Is possible. Since human vision is particularly sensitive to the green component, a configuration in which the specific color is green is particularly suitable.

  In a more preferred aspect, the total light amount used for displaying the separation component in the frame in which the display of the white image is designated is 15% or more and 20% of the total light amount used for displaying the monochromatic image in the frame. It is as follows. According to the above aspect, both color breakup and flicker are effectively suppressed.

  In a preferred aspect of the present invention, the control means displays a black image on the display body in the first or last subfield in one frame. According to the above aspect, it is possible to suppress color breakup and moving image blur. “Displaying a black image” means stopping displaying a color image. For example, when the display means is composed of a lighting device and a liquid crystal device, there is a state in which at least one of the operation of turning off the lighting device and the operation of controlling the transmittance of each pixel of the liquid crystal device to the minimum value is executed. This corresponds to a state in which a black image is displayed. Furthermore, the display means in a preferred aspect displays a black image in the last period within one frame.

  The present invention is also specified as a method of driving a display device. A driving method according to one aspect of the present invention includes a separated image signal that specifies gradation for each pixel with respect to a white component and a plurality of color components from an input image signal that specifies gradations of a plurality of primary color components for each pixel. The white component in the frame in which the white component single-color image is displayed in the subfield before or after the start of the plurality of subfields and the display of the white image is specified. Each monochromatic image is sequentially displayed on the display body based on the separated image signal in each of a plurality of subfields in one frame so that the display luminance of the monochromatic image is lower than the display luminance of the monochromatic image of each color component. Let Also by the above method, the same operation and effect as the display device of the present invention are exhibited.

<A: First Embodiment>
FIG. 1 is a block diagram showing a configuration of a display device 100 according to the first embodiment of the present invention. As shown in FIG. 1, the display device 100 includes a display body 10, an image processing circuit 20, and a control circuit 30. The image processing circuit 20 and the control circuit 30 may be installed in a single integrated circuit or distributed in separate integrated circuits.

  The display body 10 causes the observer to perceive a color image by sequentially displaying a single color image of a plurality of colors under the control of the control circuit 30 (field sequential method). The display body 10 of this embodiment includes an illumination device 12 and a liquid crystal device 14. The illumination device 12 is installed on the back side of the liquid crystal device 14 and selectively emits a plurality of types of color light to the liquid crystal device 14. The illuminating device 12 of this embodiment emits red light, green light, blue light, and white light individually by selectively emitting light of multiple colors (for example, red, green, and blue LED elements). Is possible.

  The liquid crystal device 14 is a display panel in which liquid crystal is sealed in a gap between a pair of substrates facing each other. As the liquid crystal of the liquid crystal device 14, a liquid crystal that responds at high speed such as an OCB (Optically Compensated Bend) mode is suitably employed. The liquid crystal device 14 includes a plurality of pixel electrodes 142 arranged in a matrix corresponding to each pixel. By changing the orientation of the liquid crystal according to the potential of the pixel electrode 142, the gradation (transmittance) of each pixel is controlled for each pixel electrode 142.

  FIG. 2 is a conceptual diagram for explaining the operation of the display body 10. A frame F in FIG. 2 is a period used for displaying one color image. The frame F is divided into a plurality (five in this embodiment) of subfields SF (SF1 to SF5). The display body 10 sequentially displays a plurality of single-color images each corresponding to a separate single color for each subfield SF. By visually recognizing monochromatic images for each subfield SF, the observer perceives a color image in which each color is mixed. Therefore, a color filter is not necessary for the liquid crystal device 14.

  The image processing circuit 20 in FIG. 1 generates a separated image signal S2 from the input image signal S1. The input image signal S1 is a signal that designates the gradation of each of the plurality of primary color components (red, green, blue) for each pixel. That is, as shown in FIG. 1, the input image signal S1 includes a gradation G1_R of a red component (hereinafter referred to as “R component”), a gradation G1_G of a green component (hereinafter referred to as “G component”), and a blue component (hereinafter “ A gradation G1_B of “B component”) is designated for each pixel.

  The separated image signal S2 is a signal for designating the gradation of each component for each pixel when the display color designated by the input image signal S1 is separated into a plurality of color components (red, green, blue) and a plurality of white components. It is. As shown in FIG. 1, the separated image signal S2 of the present embodiment includes a first white component (hereinafter referred to as “W1 component”) in addition to the R component gradation G2_R, the G component gradation G2_G, and the B component gradation G2_B. ) And a second white component (hereinafter referred to as “W2 component”) gradation G2_W2 are designated for each pixel.

  FIG. 3 is a conceptual diagram for explaining the operation of the image processing circuit 20. In part (A) of FIG. 3, when white display (maximum gradation value) is designated, the gradations (G1_R, G1_G, G1_B) of the respective primary color components of the input image signal S1 are set to the maximum value. It is a schematic diagram showing a situation. Part (B) in FIG. 3 is a gradation (G2_R, G2_G, G2_B, G2_W1, G2_W2) specified by the separated image signal S2 generated from the input image signal S1 of part (A).

  As shown in part (B) of FIG. 3, when the gradations (G1_R, G1_G, G1_B) of the three kinds of primary color components specified by the input image signal S1 exceed the predetermined value TH, the separated image signal S2 , The difference value between the gradation G1_R and the predetermined value TH is set to the R component gradation G2_R, the difference value between the gradation G1_G and the predetermined value TH is set to the G component gradation G2_G, and the gradation G1_B And the predetermined value TH is set to the B component gradation G2_B. Further, the gradation G2_W1 of the W1 component and the gradation G2_W2 of the W2 component of the separated image signal S2 are set to a value half the predetermined value TH. When the gradation of any primary color component is less than half of the predetermined value TH in the input image signal S1, both the gradation G2_W1 and the gradation G2_W2 are set to zero. In the input image signal S1, when the gradations of all the primary color components exceed half of the predetermined value TH but the gradations of any primary color component are lower than the predetermined value TH, the gradation G2_W1 is equal to the predetermined value TH. The gradation value G2_W2 is set to zero while being set to half.

  As shown in FIG. 2, each subfield SF includes a writing period PW and a display period PD. The writing period PW is a period for setting the gradation of each pixel of the liquid crystal device 14 according to the separated image signal S2 (that is, forming an image on the liquid crystal device 14). The display period PD is a period in which an image (monochromatic image) formed on the liquid crystal device 14 in the writing period PW is actually displayed so as to be perceived by the user. The display period PD is set to, for example, a half time length of the subfield SF (duty ratio = 50%).

  The control circuit 30 in FIG. 1 displays a B component monochrome image on the display body 10 in the display period PD of the subfield SF2, and displays a G component monochrome image on the display body 10 in the display period PD of the subfield SF3. Then, the monochrome image of the R component is displayed on the display body 10 in the display period PD of the subfield SF4. Further, the control circuit 30 displays the W1 component monochrome image on the display body 10 in the display period PD of the subfield SF1, and displays the W2 component monochrome image on the display body 10 in the display period PD of the subfield SF5. . That is, when focusing on one frame F, each monochrome image is sequentially displayed on the display body 10 in the order of W1 component → B component → G component → R component → W2 component. The control circuit 30 will be described in detail below. Note that the order of each color component for displaying a single color image in the subfields SF2 to SF4 is appropriately changed.

  As shown in FIG. 1, the control circuit 30 includes a liquid crystal drive circuit 32 that drives the liquid crystal device 14 and an illumination drive circuit 34 that drives the illumination device 12. In addition, the aspect of mounting the control circuit 30 is arbitrary. For example, a configuration in which the liquid crystal drive circuit 32 is mounted on the liquid crystal device 14 and the illumination drive circuit 34 is mounted on the illumination device 12 or a configuration in which the liquid crystal drive circuit 32 and the illumination drive circuit 34 are mounted on a single integrated circuit is adopted. Is done.

  The liquid crystal driving circuit 32 sets (writes) the potential of each pixel electrode 142 of the liquid crystal device 14 in accordance with the separated image signal S2 in the writing period PW of each subfield SF, thereby producing a monochromatic image on the liquid crystal device 14. Form. For example, as shown in FIG. 2, in the writing period PW of the subfield SF1, the liquid crystal driving circuit 32 supplies a potential corresponding to the gradation G2_W1 to each pixel electrode 142 (G2_W1 writing), and the writing of the subfield SF2 is performed. In the writing period PW, a potential corresponding to the gradation G2_B is supplied to each pixel electrode 142 (G2_B writing), and in the writing period PW of the subfield SF5, a potential corresponding to the gradation G2_W2 is supplied to each pixel electrode 142. Condition.

  The illumination drive circuit 34 controls the illumination device 12 so that any one of a plurality of types of color light (including white light) is irradiated to the liquid crystal device 14 for each display period PD. That is, the illumination driving circuit 34 emits white light to the illumination device 12 in the display period PD of each of the subfields SF1 and SF5, emits blue light in the display period PD of the subfield SF2, and displays the display period of the subfield SF3. Green light is emitted in PD, and red light is emitted in the display period PD of subfield SF4. The illumination device 12 is turned off during periods other than the display periods PD.

  As shown in FIG. 2, the intensity (luminance) of the white light emitted from the illumination device 12 in each of the subfields SF1 and SF5 is the color light (red light / blue) emitted from the illumination device 12 in each of the subfields SF2 to SF4. It is lower than the intensity of light / green light. Therefore, in the frame F in which the display of the white image is designated as shown in FIG. 3 (that is, the frame F in which the transmittance of the liquid crystal is set to 100%), the display luminance of the monochrome image of the W1 component or the W2 component is the color component. It is lower than the display brightness of the monochrome image of (R component / B component / G component).

  Now, the total amount of light used for display within the frame F in which the display of the white image is designated (hereinafter referred to as “total light amount”) is A0. The total light amount A0 is a numerical value obtained by adding the time integral value of the intensity of light emitted from the illuminating device 12 in the display period PD (light emission amount in the display period PD) for all the subfields SF1 to SF5 in the frame F. In addition, the total light emission amount (hereinafter referred to as “white light amount”) used for displaying the monochrome image of the W1 component and the W2 component in the frame F in which the display of the white image is designated is defined as AW. The white light quantity AW is a total value of the light emission amount (time integrated value of the intensity of the emitted light) of the illumination device 12 in the subfield SF1 and the light emission amount of the illumination device 12 in the subfield SF5. In the present embodiment, the illumination device in each display period PD so that the ratio p of the white light amount AW to the total light amount A0 (hereinafter referred to as “light amount ratio”, p = AW / A0 × 100 [%]) satisfies the following condition. The brightness of 12 and the time length of each display period PD are set.

  First, the condition of the light quantity ratio p is examined from the viewpoint of suppressing flicker. FIG. 4 is a graph showing the relationship between the light amount ratio p and the degree of flicker perceived by the observer (hereinafter referred to as “flicker amount”) AF. The frequency component including FFT (Fast Fourier Transform) processing is performed on the temporal variation (waveform) of the intensity of the emitted light from the display body 10 in the frame F, so that the direct current component intensity T0 The intensity T1 of the first harmonic (fundamental frequency) component is specified. The flicker amount AF is defined as a relative ratio (F = T1 / T0) of the intensity T1 of the first harmonic component to the intensity T0 of the DC component.

  As the amount of light emitted from the display body 10 in the subfields SF1 and SF5 increases, the variation in the amount of light emitted to the observation side in the entire frame F is reduced. As shown in FIG. The quantity A F decreases. In order to suppress the flicker amount A F to the allowable value A F0 or less, it is necessary to set the light amount ratio p to 30% or more. Therefore, the luminance of the illumination device 12 in each display period PD and the time length of each display period PD are set so that the light quantity ratio p is 30% or more. More specifically, the amount of light (the amount of light in the subfield SF1 and the amount of light in the subfield SF5) used for displaying the monochrome images of the W1 component and the W2 component is set to 15% or more of the total light amount A0 in the frame F. The

  Next, the condition of the light amount ratio p is examined from the viewpoint of suppressing color breakup. FIG. 5 is a conceptual diagram for explaining an image perceived by the observer when the element E displayed on the display body 10 moves in the X direction (horizontal axis). Part (A) of FIG. 5 shows a state in which a white element E displayed with black as a background moves by a change amount dX in the X direction for each frame F. When the observer's line of sight moves in the direction of arrow AR in FIG. 5, the change in luminance in the direction of arrow AR is integrated (averaged) on the observer's retina. Therefore, the luminance actually perceived by the observer changes along the X direction, for example, as shown in the part (B1) of FIG. That is, the observer perceives a continuous decrease in luminance (moving image blur) in the vicinity of the contour opposite to the direction of movement in element E. Considering the visual characteristic that it is difficult to identify a change in luminance of about 15% when a moving object is visually recognized, 85% of the maximum luminance from the point where the luminance perceived by the observer is 15% of the maximum luminance (100%). The region Δ up to the point becomes is perceived as moving image blur. In the field sequential method, since a single color image of a different color is displayed in each subfield SF, the observer perceives color breakup within the region Δ. As the area Δ increases, the color break perceived by the observer becomes more prominent.

  As shown in FIG. 5, the range in the X direction in which the luminance changes from 0% to 100% is divided into regions L1 to L3. As described above with reference to FIG. 2, since the display luminance in the subfields SF1 and SF5 at both ends of the frame F is lower than the display luminance in the subfields SF2 to SF4, the regions L1 and L3 change in luminance more than the region L2. Is moderate.

  Parts (B1) to (B3) in FIG. 5 represent changes in luminance in each case where the light quantity ratio p is changed. The part (B1) in FIG. 5 is a case where the light quantity ratio p is set to 10%. Further, the part (B2) in FIG. 5 is a case where the light quantity ratio p is set to 40%, and the part (B3) in FIG. 5 is a case where the light quantity ratio p is set to 60%. As understood from the portions (B1) to (B3) of FIG. 5, the amount of change in luminance in the regions L1 and L3 increases as the light amount ratio p increases (the change in luminance becomes steep).

  In the part (B1) of FIG. 5, the luminance at the boundary Ba between the region L1 and the region L2 exceeds 85%, and the luminance at the boundary Bb between the region L2 and the region L3 is less than 15%. That is, there is only a region L2 in which the luminance changes sharply in the region Δ where the observer perceives color breakup (moving image blur). Therefore, when the light quantity ratio p is set to 10%, color breakup is sufficiently suppressed.

  On the other hand, in the part (B3) of FIG. 5, the luminance at the boundary Ba is lower than 85% and the luminance at the boundary Bb is higher than 15%. That is, regions L1 and L3 in which the change in luminance is gentler than region L2 are included in region Δ where the viewer perceives color breakup. Therefore, when the light quantity ratio p is set to 60%, color breakup is perceived over a wide area Δ in the X direction.

  As described above, when the region Δ includes the region L1 and the region L2, color breakup becomes obvious. Therefore, the light amount ratio p is selected so that the luminance at the boundary Ba between the region L1 and the region L2 exceeds 85% of the maximum luminance and the luminance at the boundary Bb between the region L2 and the region L3 is less than 15% of the maximum luminance. The When the light quantity ratio p is set to 40% as in the part (B2) of FIG. 5, the luminance at the boundary Ba is 85% of the maximum luminance, and the luminance at the boundary Bb is 15% of the maximum luminance. Therefore, the light amount ratio p is set to 40% or less. More specifically, the amount of light (the amount of light emitted in the subfield SF1 and the amount of light emitted in the subfield SF5) used for displaying the monochrome images of the W1 component and the W2 component is 20% of the total light amount A0 in the frame F. Set to:

  As described above, in the present embodiment, the single color of the white component (W1 component, W2 component) in the subfields SF1 and SF5 before and after the start of the subfields SF2 to SF4 in which the monochrome image of each color component is displayed. Since the image is displayed, it is possible to suppress color breakup perceived by the observer. In addition to the subfields SF2 to SF4, the display luminance increase / decrease cycle is shortened by displaying the monochromatic image also in the subfields SF1 and SF5, so that flicker can be suppressed. Further, since the light quantity ratio p is set within a range from 30% where the flicker amount AF is less than the allowable value AFO to 40% where the color breakup (moving image blur) is effectively suppressed, both flicker and color breakup are eliminated. There is an advantage that it can be reduced.

<B: Second Embodiment>
Next, a second embodiment of the present invention will be described. In addition, about the element which an effect | action and function are equivalent to 1st Embodiment among this form, the same code | symbol as above is attached | subjected, and each detailed description is abbreviate | omitted suitably.

  FIG. 6 is a conceptual diagram for explaining the operation of the image processing circuit 20. In the part (A) of FIG. 6, as in FIG. 3, the case where the input image signal S <b> 1 indicates white display (maximum gradation value) is illustrated. The image processing circuit 20 generates a separated image signal S2 from the input image signal S1 as in the first embodiment. The separated image signal S2 includes a white component (hereinafter referred to as “W component”) gradation G2_W, an R component gradation G2_R, a B component gradation G2_B, and a first green component (hereinafter referred to as “Ga component”). Gradation G2_Ga and gradation G2_Gb of the second green component (hereinafter referred to as “Gb component”) are designated.

  When the gradations (G1_R, G1_G, G1_B) of the three kinds of primary color components exceed the predetermined value TH as shown in part (A) of FIG. 6, the image processing circuit 20 is shown in part (B) of FIG. As described above, the gradation G2_W of the W component of the separated image signal S2 is set to a predetermined value TH. Similarly to the first embodiment, the image processing circuit 20 sets the difference value between the R component gradation G1_R and the predetermined value TH to the gradation G2_R, and sets the difference between the G component gradation G1_G and the predetermined value TH. The difference value is set to the gradation G2_G, and the difference value between the B component gradation G1_B and the predetermined value TH is set to the gradation G2_B. Further, the image processing circuit 20 determines the gradation G2_Ga and the gradation G2_Gb by dividing the G component gradation G2_G. For example, as shown in part (B) of FIG. 6, the gradation G2_Ga of the Ga component is set to a predetermined value THG, and the gradation G2_Gb of the Gb component is set to a difference value between the gradation G2_G and the predetermined value THG. .

  FIG. 7 is a conceptual diagram for explaining the operation of the display body 10. As shown in the figure, the control circuit 30 controls the display body 10 so that each monochrome image is displayed in the order of Ga component → B component → Gb component → R component → W component in one frame F. More specifically, the liquid crystal driving circuit 32 supplies a potential corresponding to the gradation G2_Ga of the separated image signal S2 to each pixel electrode 142 of the liquid crystal device 14 in the writing period PW of the subfield SF1 (G2_Ga writing). In the writing period PW of the subfield SF2, a potential corresponding to the gradation G2_B is supplied to each pixel electrode 142 (G2_B writing), and in the writing period PW of the subfield SF3, a potential corresponding to the gradation G2_Gb is supplied to each pixel electrode. And the like (G2_Gb writing).

  The illumination drive circuit 34 emits green light to the illumination device 12 in the display period PD of each of the subfields SF1 and SF3, emits blue light in the display period PD of the subfield SF2, and Red light is emitted in the display period PD, and white light is emitted in the display period PD of the subfield SF5. Similar to the W1 component and the W2 component in the first embodiment, the amount of green light emitted from the illumination device 12 in the display period PD of the subfield SF1 is 15% or more and 20% or less of the total light amount A0 in the frame. Is done. Similarly, the amount of white light in the subfield SF5 is not less than 15% and not more than 20% of the total amount of light A0. In the subfield SF3, the illumination device 12 emits green light having a light amount obtained by subtracting the light amount in the subfield SF1 from the light amount in the subfield SF3 in the first embodiment.

  Also in this embodiment, since the monochrome image of the W component is displayed in the subfield SF5, it is possible to reduce color breakup as in the first embodiment. In addition, since the total amount of light emitted from the illumination device 12 in the subfields SF1 and SF5 is set to be 30% to 40% of the total light amount A0 in the frame F, flicker and color are the same as in the first embodiment. Both cracks can be reduced.

  By the way, under the first embodiment, for example, when a green image is displayed in the entire region, the emitted light from the illumination device 12 is emitted to the observation side only in the subfield SF3 in the frame F. Therefore, the flickering frequency may appear due to a decrease in the flicker frequency of the light intensity perceived by the observer. In the present embodiment, the monochromatic image of the G component is displayed dispersedly in the subfields SF1 and SF3. Therefore, even when a green image is displayed, the frequency of flickering of the light intensity is about 2 in the first embodiment. Maintained twice. Therefore, there is an advantage that flicker is reduced as compared with the first embodiment.

<C: Modification>
Various modifications are added to the above embodiments. Specific modifications are exemplified below. Note that two or more aspects arbitrarily selected from the following examples may be appropriately combined.

(1) Modification 1
A subfield SF for stopping image display (in other words, subfield SF for displaying a black image) may be included in each frame F. For example, as shown in FIG. 8, at the end of the frame F, a black (K) display subfield SF6 is set. In the subfield SF6, a potential corresponding to the black gradation is supplied to each pixel electrode 142 in the writing period PW (K writing), and the illumination device 12 is turned off in the display period PD. According to the above embodiment, there is an advantage that color breakup and moving image blur are reduced as compared with the first embodiment and the second embodiment. A configuration in which black display is performed in the first subfield SF of the frame F is also preferable.

  In the subfield SF6, only one of the operation of supplying the potential corresponding to the black gradation to each pixel electrode 142 in the writing period PW and the operation of turning off the illumination device 12 in the display period PD is performed. May be executed. Further, although FIG. 8 illustrates the present modification based on the first embodiment, the configuration for setting the black display subfield SF6 is similarly applied to the second embodiment.

(2) Modification 2
In the second embodiment, the amount of green light in the subfield SF1 is set to 15% or more and 20% or less of the total light amount A0. However, when an image whose entire area is green (single color) is instructed by the input image signal S1, the illumination device 12 is set to have the same amount of light in the display period PD of the subfield SF1 and the display period PD of the subfield SF3. A configuration is also preferably employed. According to the above configuration, since the amount of change in the amount of light in the frame is reduced, flicker perceived by the observer can be effectively suppressed.

(3) Modification 3
In the second embodiment, the G component is divided into the Ga component and the Gb component and displayed in separate subfields SF, but the same configuration is adopted for the other color components (for example, the R component and the B component). Also good. Since human vision has the highest sensitivity to the G component, flicker when a green image is displayed becomes more prominent than when a red or blue image is displayed. Therefore, from the viewpoint of suppressing flicker, a configuration that displays the G component in a distributed manner as in the second embodiment is particularly effective.

(4) Modification 4
In the first embodiment, a single color image of a plurality of white components (W1 component, W2 component) is displayed, but one before or after the start of subfields SF2 to SF4 for displaying a single color image of each color component in frame F. A configuration for displaying a monochromatic image of a white component only in the subfield SF is also employed. In the second embodiment, the subfield SF for displaying a Ga component monochrome image is set after the end of the subfields SF2 to SF4, or the subfield SF for displaying a W component monochrome image is set to the subfield SF2 to SF1. The configuration set before the start of SF4 is also adopted. Furthermore, the structure which combined 1st Embodiment and 2nd Embodiment is also suitable. That is, the subfield SF for displaying the white component monochrome image is set before and after the start of the subfields SF2 to SF4, and the subfield for displaying the Ga component monochrome image is set before the start of the subfields SF2 to SF4 or Set after completion.

(5) Modification 5
In each of the above embodiments, the display brightness of each monochromatic image is controlled by adjusting the light amount of the illumination device 12, but the method of adjusting the display brightness of the monochromatic image is appropriately changed. For example, in all the subfields SF (SF1 to SF5) in the frame F, the same amount of light is emitted from the illumination device 12, while the potential supplied to each pixel electrode 142 of the liquid crystal device 14 is applied to the subfields SF1 and SF5. (Ie, by controlling the monochrome image of the W1 component or W2 component formed on the liquid crystal device 14 to a low gradation), the display luminance in the subfields SF1 and SF5 is lower than that in the subfields SF2 to SF4. A configuration for setting is also adopted. The same applies to the subfield SF1 of the second embodiment.

(6) Modification 6
The color component for which the input image signal S1 and the separated image signal S2 specify the gradation is not limited to the combination of the R component, the G component, and the B component. For example, a configuration in which the input image signal S1 and the separated image signal S2 specify gradations of color components (primary color components) such as a cyan component, a magenta component, and a yellow component is also employed. Further, the wavelength (hue) of the emitted light from the illumination device 12 is appropriately changed according to the hue of the monochromatic image.

(7) Modification 7
The configuration of the display body 10 is arbitrary. For example, various display devices such as an apparatus that displays an image using an organic EL element or an LED (Light Emitting Diode) element as a pixel, or a plasma display apparatus are employed as the display body 10.

<D: Application example>
Next, an electronic apparatus using the display device according to the present invention will be described. FIGS. 9 to 11 show forms of electronic devices that employ the display device 100 according to any of the forms described above.

  FIG. 9 is a perspective view illustrating a configuration of a mobile personal computer that employs the display device 100. The personal computer 2000 includes a display device 100 that displays various images, and a main body 2010 on which a power switch 2001 and a keyboard 2002 are installed.

  FIG. 10 is a perspective view illustrating a configuration of a mobile phone to which the display device 100 is applied. A cellular phone 3000 includes a plurality of operation buttons 3001, scroll buttons 3002, and a display device 100 that displays various images. By operating the scroll button 3002, the screen displayed on the display device 100 is scrolled.

  FIG. 11 is a perspective view illustrating a configuration of a personal digital assistant (PDA) to which the display device 100 is applied. The information portable terminal 4000 includes a plurality of operation buttons 4001, a power switch 4002, and a display device 100 that displays various images. When the power switch 4002 is operated, various information such as an address book and a schedule book are displayed on the display device 100.

  Note that examples of the electronic apparatus to which the display device according to the present invention is applied include the digital still camera, the television, the video camera, the car navigation apparatus, the pager, the electronic notebook, the electronic paper, in addition to the apparatuses illustrated in FIGS. Examples include calculators, word processors, workstations, videophones, POS terminals, printers, scanners, copiers, video players, devices equipped with touch panels, and the like.

It is a block diagram which shows the structure of the display apparatus which concerns on 1st Embodiment of this invention. It is a timing chart showing operation | movement of a display apparatus. It is a conceptual diagram for demonstrating the operation | movement which produces | generates a separated image signal. It is a graph which shows the relationship between light quantity ratio and the amount of flicker. It is a conceptual diagram for demonstrating the conditions of the light quantity ratio which suppresses a color break. It is a conceptual diagram for demonstrating the operation | movement which produces | generates a separated image signal in 2nd Embodiment of this invention. It is a timing chart showing operation | movement of a display apparatus. It is a timing chart showing operation of a display concerning a modification. It is a perspective view which shows the specific example of the electronic device which concerns on this invention. It is a perspective view which shows the specific example of the electronic device which concerns on this invention. It is a perspective view which shows the specific example of the electronic device which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Display apparatus, 10 ... Display body, 12 ... Illumination device, 14 ... Liquid crystal device, 20 ... Image processing circuit, 30 ... Control circuit, 32 ... Liquid crystal drive circuit, 34 ... Illumination drive circuit , F... Frame, SF (SF1, SF2,...) .Sub.field, PW... Writing period, PD.

Claims (8)

A display body in which a plurality of pixels are arranged;
Separating means for generating a separated image signal for designating gradation for each pixel with respect to a white component and a plurality of color components from an input image signal for designating gradation of a plurality of primary color components for each pixel;
In each of the plurality of subfields in one frame, the single color image of the white component is displayed in a subfield before or after the start of the plurality of subfields displaying the single color image of each color component. Control means for sequentially displaying each single color image on the display body based on the separated image signal,
In a frame in which display of a white image is specified, the display luminance of the white component single-color image is lower than the display luminance of each color component single-color image. The separation unit generates the separated image signal that specifies gradations for the plurality of color components, the first white component, and the second white component,
The control unit displays the monochrome image of the first white component on the display body in a subfield before the start of a plurality of subfields that display the monochrome image of each color component, and displays the monochrome image of each color component And displaying the monochrome image of the second white component on the display body in a subfield after completion of the plurality of subfields,
2. The display device according to claim 1, wherein, in a frame in which display of a white image is designated, display brightness of the single color image of each of the first white component and the second white component is lower than display brightness of the single color image of each color component. . The total amount of light used for displaying the white component monochromatic image in the frame in which the display of the white image is designated is used for displaying the monochromatic image of the white component and each of the plurality of color components in the frame. 3. The display device according to claim 1, wherein the display device is 30% or more and 40% or less of a total light amount. The separation means extracts a separation component for a specific color from the plurality of color components;
3. The display according to claim 1, wherein the control unit causes the display device to display the monochrome image of the separation component in a subfield before or after the start of the plurality of subfields that display the monochrome image of each color component. apparatus. The total light amount used for displaying the separation component in a frame in which display of a white image is designated is 15% or more and 20% or less of the total light amount used for displaying a monochromatic image in the frame. 4. Display device. The display device according to claim 1, wherein the control unit displays a black image on the display body in a first or last subfield in one frame.   An electronic apparatus comprising the display device according to claim 1. From the input image signal that specifies the gradation of a plurality of primary color components for each pixel, a separated image signal that specifies the gradation for each pixel for a white component and a plurality of color components is generated,
The white component monochromatic image is displayed in a subfield before or after the start of the plurality of subfields displaying the monochromatic image of each color component, and the white component is displayed in a frame in which the display of the white image is designated. Each monochrome image is sequentially applied to the display body based on the separated image signal in each of a plurality of subfields in one frame so that the display brightness of the monochrome image is lower than the display brightness of the monochrome image of each color component. Display device driving method.

Images