JP2008268322A - Display device, driving method of display device, and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress a flicker due to display of a monochromatic image of a white component on a display device of a field sequential system. <P>SOLUTION: A separating circuit 44 generates a separated image signal S2 specifying gradation by a plurality of primary color components and a plurality of white components from an input image signal S1 specifying gradation of the plurality of primary color components by pixels. A lighting device 10 and a liquid crystal device 20 display monochromatic images of the respective primary color components and respective white components in sequence on the basis of the separated image signal S2 for a plurality of sub-fields SF in a frame F so that the sub-fields SF corresponding to the plurality of white components are mutually separated on a time base. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a technique for displaying an image by a frame sequential method (field sequential method).

In a surface sequential display device that allows a viewer to perceive a color image by sequentially displaying each single color image of a plurality of primary color components (for example, red, green, and blue) in a time-sharing manner, a color mixture of the plurality of primary color components The phenomenon that each primary color component is perceived separately at the edge of the moving image represented by (hereinafter referred to as “color breakup”) becomes a problem. Patent Document 1 discloses a technique for reducing color breakup by sequentially displaying monochromatic images for a white component extracted from a plurality of primary color components and each of the plurality of color components.
JP 2002-169515 A

  However, in the technique of Patent Document 1, particularly when the display color of the image is close to white, the white component single-color image has a higher gradation (high luminance) than the other color component single-color images. Then, there is a problem that flicker perceived by the observer becomes obvious by sequentially displaying a plurality of monochrome images having different gradations. Against the background of the above circumstances, an object of the present invention is to solve the problem of suppressing flicker caused by display of a white component monochrome image in a frame sequential display device.

  In order to solve the above problems, a display device according to the present invention includes a plurality of color components (primary color components, or primary color components and mixed color components) from an input image signal that specifies gradations of the plurality of primary color components for each pixel. 1) such that the separating means for generating the separated image signal for designating the gradation for the plurality of white components and the subfields corresponding to each of the plurality of white components are separated from each other on the time axis. Each of the plurality of subfields in the frame includes display means (for example, the illumination device 10 and the liquid crystal device 20 in FIG. 1) that sequentially displays single-color images of each color component and each white component based on the separated image signal. . The display means includes, for example, a liquid crystal device in which an OCB mode liquid crystal is sealed in a gap between the first substrate and the second substrate. The display device of the present invention is used in various electronic devices.

  In the above configuration, since each single-color image of a plurality of white components is displayed in each subfield that is separated from each other on the time axis, compared to a configuration in which the white component is displayed in only one subfield. The gradation (brightness) of the monochromatic image of the white component is suppressed. Therefore, it is possible to reduce flicker due to the display of the monochromatic image of the white component.

  The order of displaying the monochrome image of each color component and the monochrome image of each white component is arbitrary. For example, in one aspect of the present invention, the display means displays a white component monochrome image in each subfield before and after the plurality of subfields displaying a plurality of color component monochrome images. Further, if the display means displays a monochromatic image of a white component in a subfield of a gap between a plurality of subfields displaying a monochromatic image of a plurality of color components, it is difficult for an observer to perceive color breakup. Is possible.

  In a preferred aspect of the present invention, the display means displays a black image in a predetermined period within one frame. According to this aspect, color breakup is suppressed by shortening the period for displaying the single color image of the color component, and moving picture blurring is achieved by shortening the period for displaying the single color image of the color component and the white component. There is an advantage that it is suppressed. Note that “display a black image” means stopping display of 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.

  In a preferred aspect of the present invention, the display means displays a single color image of at least one white component among the plurality of white components in a subfield having a longer time than the subfield displaying the single color image of each color component. According to the above aspect, since a sufficient period for displaying the monochrome image of the color component and the white component is ensured, flicker can be effectively suppressed.

  In a preferred aspect of the present invention, the separating means generates a separated image signal by including two color mixture components of the plurality of primary color components in the plurality of color components. According to the above aspect, color breakup can be made difficult to be perceived as compared with a configuration in which single-color images of primary color components are continuously displayed. In a further preferred aspect, the subfield that displays the monochromatic image of the mixed color component is interposed between the subfields that display the monochromatic image of the primary color component.

  The present invention is also specified as a method of driving a display device. In the driving method according to the present invention, 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 a plurality of color components and a plurality of white components is generated, Based on the separated image signal, each color component and each monochromatic image of each white component in each of the plurality of subfields in one frame so that the subfields corresponding to each of the plurality of white components are separated from each other on the time axis. Are sequentially displayed on the display device. The same effect as the display device of the present invention can be obtained by the above driving method.

<A: First Embodiment>
FIG. 1 is a block diagram showing a configuration of a display device according to the first embodiment of the present invention. As shown in the figure, the display device 100 includes an illumination device 10, a liquid crystal device 20, an image processing device 40, and a control device 50. The image processing device 40 and the control device 50 may be installed in a single integrated circuit or may be installed separately in separate integrated circuits.

  The illumination device 10 is installed on the back side of the liquid crystal device 20 to illuminate the liquid crystal device 20. The illumination device 10 includes a plurality of light emitters 12 (12R, 12G, 12B) each corresponding to a separate primary color component, and a light guide member 14 that guides the emitted light from each light emitter 12 to the liquid crystal device 20 side. . The light emitter 12R outputs light having a wavelength corresponding to red (red light). Similarly, the light emitter 12G emits green light, and the light emitter 12B emits blue light. In practice, a reflecting plate or a scattering plate is attached to the light guide 14, but is omitted in FIG. 1 for convenience.

  The liquid crystal device 20 includes a first substrate 21 and a second substrate 22 that face each other. Liquid crystal (not shown) is sealed in the gap between the first substrate 21 and the second substrate 22. A liquid crystal that responds at high speed such as an OCB (Optically Compensated Bend) mode is preferably used. On the surface of the second substrate 22 facing the liquid crystal, a plurality of pixel electrodes 24 corresponding to each pixel of the image are arranged in a matrix. The orientation of the liquid crystal sandwiched between the first substrate 21 and the second substrate 22 changes according to the potential difference between each pixel electrode 24 and the counter electrode (not shown) on the surface of the first substrate 21. Therefore, the ratio (transmittance) of the amount of light transmitted to the observation side in the irradiation light from the illumination device 10 is controlled for each pixel electrode 24.

  The illumination device 10 and the liquid crystal device 20 cooperate to display a color image. FIG. 2 is a timing chart for explaining operations of the illumination device 10 and the liquid crystal device 20. A frame F illustrated in FIG. 2 is a period used for displaying one color image. As shown in the figure, the frame F is divided into a plurality (six in this embodiment) of subfields SF (SF1 to SF6). The illuminating device 10 and the liquid crystal device 20 sequentially display a plurality of images (hereinafter referred to as “monochromatic images”) corresponding to separate single colors in each subfield SF (frame sequential method). By visually recognizing the single color image for each subfield SF, the observer perceives a color image in which each color is mixed. Therefore, a colored layer (color filter) is not necessary for the liquid crystal device 20.

  The image processing device 40 in FIG. 1 processes an input image signal S1 supplied from an external device. The input image signal S1 is a signal that designates the display color of each pixel constituting the image. The input image signal S1 individually designates a gradation for each of the three types of primary color components (red, green and blue) constituting the display color of the pixel. That is, 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 referred to as “B component”). The key G1_B is designated for each pixel.

  As shown in FIG. 1, the image processing apparatus 40 includes a storage circuit 42 and a separation circuit 44. The storage circuit 42 is a frame memory that stores an input image signal S1 for each pixel of an image displayed in one frame F. The separation circuit 44 generates and outputs a separated image signal S2 from the input image signal S1 stored in the storage circuit 42. The separated image signal S2 is a signal that designates 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 primary color components and a plurality of white components. As shown in FIG. 1, the separated image signal S2 of the present embodiment includes a first white component (hereinafter referred to as “W1”) in addition to the R component gradation G2_R, the G component gradation G2_G, and the B component gradation G2_B. The tone G2_W1 of the “component”) and the tone G2_W2 of the second white component (hereinafter referred to as “W2 component”) are designated.

  FIG. 3 is a flowchart for explaining the operation of the separation circuit 44. The process shown in FIG. 6 is executed for each pixel constituting the image. The separation circuit 44 specifies the minimum value Gmin from the gradations (G1_R, G1_G, and G1_B) of the three primary color components that the input image signal S1 designates for one pixel (step S1). Next, the separation circuit 44 determines whether or not the minimum value Gmin specified in step S1 is lower than the threshold value TH1 (step S2). The threshold value TH1 is typically a preset fixed value, but may be a variable value according to an instruction from a user or a host device, for example.

  Part (a) in FIG. 4 and part (a) in FIG. 5 show specific examples of gradations (G1_R, G1_G, and G1_B) that the input image signal S1 designates for each primary color component. In the display color illustrated in part (a) of FIG. 4, the G component gradation G1_G of the three primary color components is the minimum value Gmin below the threshold TH1. When the minimum value Gmin is lower than the threshold value TH1 as shown in part (a) of FIG. 4, the separation circuit 44 designates the minimum value Gmin specified in step S1 as the gradation G2_W1 of the W1 component and the gradation of the W2 component. A separated image signal S2 designating G2_W2 as zero is generated (step S3). Further, the separation circuit 44 uses the numerical values obtained by subtracting the minimum value Gmin from the gradations (G1_R, G1_G, G1_B) of each of the three primary color components as the gradations (G2_R, G2_G, G2_B) of the respective primary color components. It designates with S2 (step S4).

  For example, when the display color of the part (a) in FIG. 4 is designated, the separation circuit 44, as shown in the part (b) in FIG. 4, the gradation G1_G (minimum value Gmin) of the G component in the input image signal S1. ) Is designated as the gradation G2_W1 of the W1 component. Further, the separation circuit 44 designates the difference value between the R component gradation G1_R and the minimum value Gmin as the gradation G2_R, and designates the difference value between the B component gradation G1_B and the minimum value Gmin as the gradation G2_B. . The G component gradation G2_G (G2_G = G1_G−Gmin) in the separated image signal S2 is zero.

  On the other hand, in the display color of the part (a) in FIG. 5, the G component gradation G1_G, which is the minimum value Gmin among the gradations of the three primary color components, exceeds the threshold value TH1. When the result of step S2 is negative as shown in part (a) of FIG. 5, the separation circuit 44 designates the threshold value TH1 as the gradation G2_W1 of the W1 component and sets the difference value between the minimum value Gmin and the threshold value TH1 to W2. A separated image signal S2 designated as the component gradation G2_W2 is generated (step S5). Further, the separation circuit 44 subtracts a numerical value obtained by subtracting the minimum value Gmin (or the added value of the gradation G2_W1 (TH1) and the gradation G2_W2) from the gradation (G1_R, G1_G, G1_B) of each of the three primary color components. The gray level (G2_R, G2_G, G2_B) of each primary color component is designated by the separated image signal S2 (step S4).

  For example, when the display color of the part (a) in FIG. 5 is designated, the separation circuit 44 designates the threshold value TH1 as the gradation G2_W1 of the W1 component and the gradation G1_G (minimum value Gmin) of the G component and the threshold value TH1. Is designated as the gradation G2_W2 of the W2 component. Further, the separation circuit 44 designates the difference value between the R component gradation G1_R and the minimum value Gmin as the gradation G2_R, and designates the difference value between the B component gradation G1_B and the minimum value Gmin as the gradation G2_B. . The gradation G2_G of the G component in the separated image signal S2 is zero. As described above, when the gradation of the white component (W1 + W2) in the display color specified by the input image signal S1 exceeds the threshold value TH1, the white component is separated into the W1 component and the W2 component with the threshold value TH1 as a boundary. The

  The control device 50 in FIG. 1 is a circuit that controls the lighting device 10 and the liquid crystal device 20. The control device 50 includes an illumination drive circuit 52 that drives the illumination device 10 and a liquid crystal drive circuit 54 that drives the liquid crystal device 20. Note that the control device 50 may be mounted in any manner. For example, a configuration in which the illumination drive circuit 52 is mounted on the illumination device 10 and the liquid crystal drive circuit 54 is mounted on the liquid crystal device 20 or a configuration in which the illumination drive circuit 52 and the liquid crystal drive circuit 54 are mounted on a single integrated circuit is adopted. Is done.

  As shown in FIG. 2, the illumination drive circuit 52 controls the light emission / extinction of each of the plurality of light emitters 12 (12R, 12G, 12B) for each subfield SF. That is, the illumination driving circuit 52 causes the light emitter 12R to emit light in the second subfield SF2, causes the light emitter 12G to emit light in the third subfield SF3, and emits light in the fourth subfield SF4. The body 12B is caused to emit light. The illumination driving circuit 52 causes all the light emitters 12 (12R, 12G, 12B) to emit light in the first subfield SF1 and the fifth subfield SF5, and in the sixth subfield SF6. All the light emitters 12 are turned off. Therefore, in the subfields SF2 to SF4, the color light of each primary color component is sequentially irradiated to the liquid crystal device 20, the white light is irradiated to the liquid crystal device 20 in the subfields SF1 and SF5, and the light irradiation to the liquid crystal device 20 is performed in the subfield SF6. Stop.

  The liquid crystal drive circuit 54 controls the transmissivity of the liquid crystal corresponding to each pixel electrode 24 for each subfield SF according to the gradation specified by the separated image signal S2 for each pixel. In other words, the liquid crystal driving circuit 54 applies a potential (hereinafter referred to as “data potential”) according to the gradation specified by the separated image signal S2 to each pixel to the pixel electrode 24 corresponding to the pixel in each subfield SF. Supply at the beginning. In the subfield SF in which the illuminating device 10 emits illumination light corresponding to any of the plurality of primary color components and the plurality of white components, the data potential depends on the gradation specified by the separated image signal S2 for the component. Is set.

  More specifically, the liquid crystal drive circuit 54 supplies a data potential corresponding to the R component gradation G2_R of each pixel to each pixel electrode 24 in the subfield SF2 irradiated with red light. Similarly, in the subfield SF3, the data potential corresponding to the gradation G2_G is supplied to the pixel electrode 24, and in the subfield SF4, the data potential corresponding to the gradation G2_B is supplied to the pixel electrode 24. Further, the liquid crystal driving circuit 54 supplies a data potential corresponding to the gradation G2_W1 of the W1 component to the pixel electrode 24 in the subfield SF1 where the white light is irradiated to the liquid crystal device 20, and the white light is similarly irradiated. In the subfield SF5, a data potential corresponding to the gradation G2_W2 of the W2 component is supplied to the pixel electrode 24. Further, the liquid crystal driving circuit 54 supplies a data potential for controlling the transmittance of the liquid crystal to the lowest value (for example, zero) to all the pixel electrodes 24 in the subfield SF6 where the lighting device 10 is turned off. Therefore, as shown in FIG. 2, a monochrome image corresponding to each of the plurality of primary color components (R, G, B) and the plurality of white components (W1, W2) is sequentially displayed for each subfield SF. Subfields SF2 to SF4 for displaying the primary color component monochromatic images are interposed between the subfield SF1 for displaying the W1 component monochromatic image and the subfield SF5 for displaying the W2 component monochromatic image. That is, the W1 component subfield SF1 and the W2 component subfield SF5 are separated from each other on the time axis. In the subfield SF6, a black image is displayed for all pixels.

  As described above, in this embodiment, since the monochrome image of the white component (W1, W2) is displayed in addition to the monochrome image of each primary color component, it is compared with the case where only the monochrome image of each primary color component is displayed. Thus, it is possible to suppress the color breakup of the image perceived by the observer. The details of the suppression of color breakup are as follows.

  As shown in FIG. 6, assuming that a rectangular subject P (width D) displayed with a black background moves to the right with time at a substantially constant speed, one line passing through the subject P is assumed. Consider the change over time in the display color at L. FIG. 7 shows a change in display color in a conventional configuration in which only a single color image of each primary color component is displayed, and FIG. 8 shows a configuration of this embodiment in which a single color image of each primary color component and each white component is displayed. The change in the display color of is shown. 7 and 8, the vertical axis indicates time. The horizontal axis is the position in the horizontal direction (horizontal direction).

  As shown in FIGS. 7 and 8, the subject P moves to the right in stages for each frame F. That is, the position of the subject P does not change within one frame F. On the other hand, the observer's viewpoint continuously moves to the right at a substantially constant speed so as to follow the movement of the subject P. As described above, since the actual movement of the subject P is different from the movement of the viewpoint, the observer perceives color breaks in the vicinity of the left and right edges of the subject P. The horizontal width CA in FIGS. 7 and 8 is a dimension in a range where color breakage is perceived on one side of the subject P (hereinafter referred to as “color breakup width”).

  The longer the period during which the primary color component monochrome image is displayed, the greater the color breakup width CA. In this embodiment, the time length for displaying the single color image of each primary color component is shortened as compared with the configuration of FIG. 7 by the period during which the monochrome image of the W1 component and the W2 component is displayed. Therefore, as shown in FIG. 8, the color break width CA perceived by the observer in this embodiment is reduced compared to the color break width CA in the case of FIG.

  Further, due to the difference between the movement of the subject P and the movement of the observer's viewpoint, a phenomenon (hereinafter referred to as “moving image blur”) in which the contour of the subject P perceived by the observer becomes unclear occurs. The horizontal width CB in FIGS. 7 and 8 is a dimension (hereinafter referred to as “moving image blur width”) of a range where motion blur is perceived on one side of the subject P (a range where the contour of the subject is perceived as unclear). The moving image blur width CB increases as the period for displaying the primary color component or the white component monochrome image is longer. In this embodiment, in addition to the subfield SF in which the monochromatic image of each primary color component and each white component is displayed, the subfield SF of the black image (the non-display subfield labeled K in the drawing) SF6 is the frame. In other words, the period for displaying the primary color component and the white color monochromatic image in this embodiment is shortened by the amount of the subfield SF6 as compared with the configuration of FIG. Thus, the moving image blur width CB perceived by the observer in this embodiment is reduced as compared with the moving image blur width CB in the case of FIG.

  By the way, in the technique of Patent Document 1 in which a single-color image of a white component extracted from the display color specified by the input image signal S1 is displayed by only one subfield SF, particularly when the display color of the image is close to white, The single-color image of the white component has a significantly higher gradation than the single-color image of other colors. Therefore, the flicker perceived by the observer becomes conspicuous by sequentially displaying the low-tone single-color image of each primary color component and the high-tone single-color image of the white component. In this embodiment, since the white component in the display color is separated into the W1 component and the W2 component, each monochrome image is displayed in a separate subfield SF (SF1, SF5). The gradation (luminance) of a monochromatic image is restricted to a range up to the threshold value TH1. That is, since the difference in gradation between the single-color image of the primary color component and the single-color image of the white component is suppressed, even when displaying an image close to white, flicker is reduced compared to Patent Document 1. There is an advantage.

  The flicker perceived by the observer is the frequency at which light is emitted to the observation side (hereinafter referred to as “light emission frequency”) and the ratio of the time during which light is emitted to the observation side in one frame F (hereinafter referred to as “light emission duty”). It depends on. That is, flicker is reduced as the emission frequency and emission duty are higher. As described with reference to FIGS. 7 and 8, when the black image subfield SF6 is inserted into the frame F in order to prevent motion blur, the light emission duty is reduced as compared with the configuration in which the subfield SF6 is not set. Setting the field SF6 causes flicker to increase. On the other hand, displaying the white component in the subfields SF (SF1, SF5) spaced apart from each other as in the present embodiment is equivalent to increasing the emission frequency, and thus acts to reduce flicker. That is, in this embodiment, it is possible to cancel the increase in flicker caused by the display of the black image by the dispersive display of the white component.

<B: Second Embodiment>
Next, a second embodiment of the present invention will be described. In the first embodiment, the configuration in which the display color specified by the input image signal S1 is separated into a plurality of primary color components and a plurality of white components is exemplified. On the other hand, the separation circuit 44 of the present embodiment uses a display color specified by the input image signal S1 as a plurality of color components including a component obtained by mixing two kinds of primary color components (hereinafter referred to as “mixed color component”) and a plurality of white components. Separated into components, a separated image signal S2 is generated. In addition, about the element which an effect | action and function are equivalent to 1st Embodiment in this form, the same code | symbol as the above is attached | subjected and each detailed description is abbreviate | omitted suitably.

  The separated image signal S2 generated by the separation circuit 44 of the present embodiment has the same three types of primary color component gradations (G2_R, G2_G, G2_B) and two types of white component gradations (G2_W1, G2_W2) as in the first embodiment. ), A gradation G2_Y of a yellow component (hereinafter referred to as “Y component”) which is a mixed color component of red and green, and a level of a cyan component (hereinafter referred to as “C component”) which is a mixed color component of green and blue. A tone G2_C and a gradation G2_M of a magenta component (hereinafter referred to as “M component”) which is a mixed color component of blue and red are designated.

  Part (a) in FIG. 9 and part (a) in FIG. 10 show specific examples of gradations (G1_R, G1_G, and G1_B) that the input image signal S1 specifies for each primary color component. In the display color illustrated in part (a) of FIG. 9, the R component gradation G1_R is the minimum value Gmin below the threshold value TH1 among the three primary color components. When the minimum value Gmin is lower than the threshold value TH1 as shown in part (a) of FIG. 9, the separation circuit 44 designates the minimum value Gmin as the gradation G2_W1 of the W1 component and the W2 component as in the first embodiment. The gradation G2_W2 is designated as zero.

  Further, the separation circuit 44 selects the gradation for the mixed color component of the two primary color components excluding the primary color component having the minimum value Gmin among the three primary color components. For example, when the R component gradation G1_R is the minimum value Gmin as shown in part (a) of FIG. 9, the separation circuit 44 determines that the G component gradation G1_G and the G component gradation G1_G as shown in part (b) of FIG. The C component gradation G2_C is set based on the B component gradation G1_B. The gradation G2_C is a numerical value obtained by subtracting the minimum value Gmin (the gradation G2_W1 of the W1 component) from the lower gradation (G1_G) of the gradation G1_G and the gradation G1_B, as shown in part (b) of FIG. is there. Further, the separation circuit 44 sets the gradation for the primary color component remaining after the separation of the W1 component and the color mixture component (C component in FIG. 9). For example, the B component gradation G2_B remaining in the part (b) of FIG. 9 is obtained by changing the C component gradation G2_C and the minimum value Gmin (W1 component gradation G2_W1) from the original B component gradation G1_B. Set to the subtracted number. Further, the gradation of the primary color component that does not remain after the separation of the mixed color component and the W1 component (the R component gradation G2_R and the G component gradation G2_G in FIG. 9) and the mixed color component including the primary color component having the minimum value Gmin. The gradations (Y component gradation G2_Y and M component gradation G2_M in FIG. 9) are designated as zero.

  On the other hand, the part (a) of FIG. 10 illustrates a display color in which the B component gradation G1_B having the minimum value Gmin exceeds the threshold value TH1. When the minimum value Gmin exceeds the threshold value TH1, the separation circuit 44 designates the threshold value TH1 as the gradation G2_W1 of the W1 component and sets the difference value between the minimum value Gmin and the threshold value TH1 as in the W2 component, as in the first embodiment. Designated as gradation G2_W2.

  Further, as in the case of FIG. 9, the separation circuit 44 selects a gradation for the mixed color component of the two primary color components excluding the primary color component having the minimum value Gmin. That is, when the B component gradation G1_B is the minimum value Gmin as shown in part (a) of FIG. 10, the separation circuit 44 determines that the R component gradation G1_R and the R component gradation G1_R as shown in part (b) of FIG. Based on the G component gradation G1_G, the Y component gradation G2_Y is set. As shown in part (b) of FIG. 10, the gradation G2_Y subtracts the minimum value Gmin (addition value of the gradation G2_W1 and the gradation G2_W2) from the lower gradation G1_G of the gradation G1_R and the gradation G1_G. It is a numerical value. Further, the separation circuit 44 determines the R component gradation G2_R remaining after the separation of the W1, W2 and Y components, the Y component gradation G2_Y and the minimum value Gmin from the original R component gradation G1_R. Set to the subtracted number. Note that the gradation of the primary color component that does not remain after the separation of the mixed color component and the W1 component (G component gradation G2_G and B component gradation G2_B in FIG. 10) and the mixed color component level including the primary color component of the minimum value Gmin. The tone (C component gradation G2_C and M component gradation G2_M in FIG. 10) is designated as zero.

  As shown in FIG. 11, one frame F is divided into nine subfields SF (SF1 to SF9). The control device 50 illuminates so that a single color image of each component (primary color component, mixed color component and white color component) whose gradation is designated by the separated image signal S2 is sequentially displayed in each of the subfields SF1 to SF8. 10 and the liquid crystal device 20 are controlled.

  The subfield SF in which the monochromatic image of the mixed color component is displayed and the subfield SF in which the monochromatic image of the primary color component is displayed are alternately arranged. That is, as shown in FIG. 11, monochromatic images of primary color components (R component, G component, B component) are sequentially displayed in the subfields SF2, SF4, and SF6, and in the subfields SF3, SF5, and SF7, Monochromatic images of mixed color components (C component, M component, Y component) are sequentially displayed. Note that, in the subfields SF3, SF5, and SF7 for displaying the monochromatic image of the mixed color component, the illumination driving circuit 52 causes the two light emitters 12 corresponding to the mixed color components to emit light simultaneously. For example, in the subfield SF3, the liquid crystal device 20 is irradiated with the C component color light by causing the light emitters 12G and 12B to emit light simultaneously.

  Each single color image of a plurality of white components (W1 component, W2 component) is subfields SF1 and SF8 before and after subfields SF2 to SF7 displaying a single color image of a plurality of color components (primary color component and mixed color component). Displayed sequentially. In the last subfield SF9 of the frame F, the black image K is displayed for all pixels (that is, the display is stopped) as in the first embodiment.

  In this embodiment, the same effect as that of the first embodiment is obtained. It should be noted that color breakup is particularly noticeable when single-color images of a plurality of primary color components are continuously displayed on the time axis. In the present embodiment, since the mixed-color component single-color image is displayed in the gap between the subfields SF where the primary-color component single-color image is displayed, color breakup is caused as compared with the first embodiment in which the display of the primary color component is continuous. Further suppression is possible.

<C: Modification>
Various modifications can be made to each of the above embodiments. An example of a specific modification is as follows. Note that two or more aspects arbitrarily selected from the following examples can be combined.

(1) Modification 1
In each of the above embodiments, a single color image of a white component (W1 component, W2 component) is displayed in each subfield SF before and after a plurality of subfields SF displaying a single color image of a plurality of color components (primary color component, mixed color component). Although the structure to display is illustrated, the order of each subfield SF is changed suitably. For example, in the first embodiment, as shown in FIG. 12, a monochrome image of W1 component is displayed in a subfield SF2 between an R component subfield SF1 and a G component subfield SF3. As shown in FIG. 13, a configuration in which a monochrome image of W2 component is displayed in a subfield SF4 between a subfield SF3 of G component and a subfield SF5 of B component is also adopted. Further, as shown in FIG. 14, a configuration in which a W1 component subfield SF2 and a W2 component subfield SF4 are both inserted between primary color component subfields SF (configuration combining FIG. 12 and FIG. 13). ) Is also suitable. According to the configuration of FIGS. 12 to 14, the subfields SF displaying the primary color component monochromatic image are separated on the time axis with the white component subfield SF interposed therebetween, and therefore the primary color component subfields SF are continuous. It is possible to make the color breakup less perceivable as compared to the configuration. In addition, although the modification of 1st Embodiment was illustrated above, similarly in 2nd Embodiment, the order which displays the monochrome image of each color is changed arbitrarily. Moreover, it is good also as a structure which changes the order which displays the monochrome image of each color for every flame | frame F. FIG.

(2) Modification 2
In the above embodiment, the configuration in which the W1 component and the W2 component are extracted from the display color is illustrated, but the number of white components separated can be arbitrarily changed. For example, three types of white components (W1 to W3) may be extracted from the display color designated by the input image signal S1. That is, when the input image signal S1 specifies the display color of the portion (a) in FIG. 15, the threshold value TH1 is specified as the gradation G2_W1 of the W1 component and the difference value between the threshold value TH2 (TH2> TH1) and the threshold value TH1. Is designated as the W2 component gradation G2_W2, and the difference value between the minimum gradation value Gmin (gradation G1_B in FIG. 15) and the threshold TH2 is designated as the W3 component gradation G2_W3.

  As illustrated in FIG. 16, single-color images of the respective primary color components are sequentially displayed in the subfields SF2, SF4 and SF5 among the seven subfields SF1 to SF7 into which the frame F is divided, and the subfields SF1, SF3 and SF6 are displayed. The monochrome images of the W1, W2 and W3 components are sequentially displayed. However, the order in which the monochrome images of the respective colors are displayed is arbitrary. For example, as shown in FIG. 17, a monochrome image of each primary color component is sequentially displayed in the even-numbered subfields SF2, SF4 and SF6 of the frame F, and each white color is displayed in the odd-numbered subfields SF1, SF3 and SF5. Monochromatic images of components may be displayed sequentially. In addition, although the modification of 1st Embodiment was illustrated in the above, the same deformation | transformation (increase in the number of separation of a white component) is applied also about 2nd Embodiment.

(3) Modification 3
In each of the above embodiments, the case where all the subfields SF in the frame F have the same time length is illustrated, but the time length of each subfield SF is appropriately changed. For example, a mode (hereinafter referred to as “mode 1”) in which the subfield SF in which the black image K is displayed is set to a longer period than the other subfields SF, or a monochrome image of the W1 component or the W2 component is displayed. A mode (hereinafter referred to as “mode 2”) in which subfield SF is set to a longer period than other subfields SF is employed. Each aspect will be described in detail as follows.

(A) Aspect 1
FIG. 18 is a timing chart showing each subfield SF in the specific example of aspect 1. As shown in the figure, the subfield SF6 in which the black image K is displayed in one frame F is longer than the subfields SF1 to SF5 in which the single color images of the primary color component and the white component are displayed.

  FIG. 19 is a conceptual diagram illustrating the change over time in the display color when the subject P in FIG. 6 is displayed in the aspect 1 in the same manner as in FIGS. 7 and 8. As shown in the figure, the time length Ta for displaying the primary color component monochromatic image in the aspect 1 is shortened as compared with the first embodiment in which all the subfields SF1 to SF6 have the same time length. Therefore, the color breakup width CA in the aspect 1 is suppressed as compared with the first embodiment (FIG. 8). Further, the time length Tb during which the primary color component and the white color monochromatic image are displayed is shorter than that of the first embodiment by the increment of the black image subfield SF6. Therefore, the moving image blur width CB in the aspect 1 is suppressed as compared with the first embodiment.

  However, if the subfield SF6 displaying the black image K is too long, there is a problem that flicker perceived by the observer becomes conspicuous. Therefore, the subfield SF6 for displaying the black image K is desirably set to a time length of 50% or less of the frame F, and more preferably a time length of 30% or less of the frame F. Further, when importance is placed on suppression of flicker caused by the display of the black image K, the subfield SF6 of the black image K is set to a time length equivalent to the other subfields SF1 to SF5 as in the first embodiment. A configuration in which the subfield SF6 of the black image K is not provided in the frame F is preferable. In addition, although the modification of 1st Embodiment was illustrated above, the same deformation | transformation (lengthening of subfield SF9 in which the black image K is displayed) is applied also to 2nd Embodiment.

(B) Aspect 2
FIG. 20 is a timing chart showing each subfield SF in the specific example of aspect 2. As shown in the figure, the subfield SF5 in which the W2 component monochrome image is displayed is set to a longer period than the other subfields SF (SF1 to SF4, SF6).

  FIG. 21 is a conceptual diagram illustrating changes over time in the display color when the subject P in FIG. 6 is displayed in the aspect 2 in the same manner as in FIGS. 7 and 8. As shown in the figure, since the time length Ta for displaying the monochromatic image of the primary color component in the aspect 2 is shortened in the same manner as in the aspect 1, the color breakup width CA in the aspect 2 is suppressed as compared with the first embodiment. The On the other hand, since the subfield SF6 on which the black image K is displayed is shortened compared to the mode 1, the mode 1 is more advantageous than the mode 2 only from the viewpoint of reducing the moving image blur width CB. However, since the extension of the subfield SF5 of the W2 component in the aspect 2 (shortening the subfield SF6 of the black image K) works equivalently to increasing the light emission duty, flicker is suppressed as compared with the aspect 1. There is an advantage of being.

  20 and 21, attention is paid to subfield SF5. However, subfield SF1 for displaying the W1 component is set longer than subfields SF2 to SF4 in place of subfield SF5 or together with subfield SF5. A configuration is also adopted. In the above, the modification of the first embodiment is exemplified, but the same modification (prolongation of at least one of the subfields SF1 and SF8) is applied to the second embodiment.

(4) Modification 4
In each of the above embodiments, in the last subfield SF of the frame F (the subfield SF6 of the first embodiment and the subfield SF9 of the second embodiment), the illumination device 10 is turned off and the transmittance of all pixels is minimized. Although the configuration in which the black image K is displayed by controlling the value (that is, the display is stopped) is illustrated, only one of the lighting device 10 extinguishing and the liquid crystal transmittance reduction is displayed in the last subfield SF. A configuration to be executed is also adopted. Further, the black image K may be displayed in the first subfield SF of the frame F. In the preferred embodiment of the present invention, it is sufficient that the display is stopped in a predetermined period in the frame F, and the time when the black image K is displayed and the method of displaying the black image K are not limited. However, a configuration in which a period for stopping the display is not provided in the frame F is also employed in the present invention.

(5) Modification 5
In each of the above embodiments, the liquid crystal device 20 is irradiated with color light corresponding to white light or mixed color components by driving the light emitters 12 (12R, 12G, 12B) corresponding to the primary color components in an appropriate combination. However, you may utilize the illuminating device 10 in which the light-emitting body which radiate | emits white light and the light-emitting body which radiate | emits the color light of a mixed color component were installed independently.

<D: Application example>
Next, an electronic apparatus using the display device according to the present invention will be described. 22 to 24 show forms of electronic devices that employ the display device 100 according to any of the forms described above.

  FIG. 22 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. 23 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. 24 is a perspective view showing 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 device 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 device, the pager, the electronic notebook, the electronic paper, in addition to the devices 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. 6 is a timing chart for explaining the operation of the display device. It is a flowchart which shows the operation | movement which a separation circuit produces | generates a separated image signal. It is a conceptual diagram which shows the specific example of the operation | movement which produces | generates a separated image signal. It is a conceptual diagram which shows the specific example of the operation | movement which produces | generates a separated image signal. It is a conceptual diagram which shows the example of a display by a display apparatus. It is a conceptual diagram which shows generation | occurrence | production of the color breakup and moving image blur in a prior art. It is a conceptual diagram which shows generation | occurrence | production of the color breakup and moving image blur in 1st Embodiment. It is a conceptual diagram which shows the specific example of the production | generation of the separated image signal in 2nd Embodiment. It is a conceptual diagram which shows the specific example of the production | generation of a separated image signal. 6 is a timing chart for explaining the operation of the display device. It is a timing chart which shows operation of a display concerning a modification. It is a timing chart which shows operation of a display concerning a modification. It is a timing chart which shows operation of a display concerning a modification. It is a conceptual diagram which shows the specific example of the production | generation of the separated image signal in a modification. It is a timing chart which shows operation of a display concerning a modification. It is a timing chart which shows operation of a display concerning a modification. It is a timing chart which shows operation of a display concerning a modification. It is a conceptual diagram which shows generation | occurrence | production of the color breakup and moving image blur in a modification. It is a timing chart which shows operation of a display concerning a modification. It is a conceptual diagram which shows generation | occurrence | production of the color breakup and moving image blur in a modification. It is a perspective view which shows the form (personal computer) of the electronic device which concerns on this invention. It is a perspective view which shows the form (cellular phone) of the electronic device which concerns on this invention. It is a perspective view which shows the form (mobile information terminal) of the electronic device which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Display apparatus, 10 ... Illuminating device, 12 ... Light-emitting body, 14 ... Light guide, 20 ... Liquid crystal device, 21 ... 1st board | substrate, 22 ... 2nd board | substrate, 24 ... Pixel electrode 40... Image processing device 42... Memory circuit 44. Separation circuit 50. Control device 52. Illumination drive circuit 54. Liquid crystal drive circuit F F. Frame SF (SF 1, SF 2 , ……) …… Subfield, CA …… Color breakup width, CB …… Video blur width.

Claims (10)

Separation means for generating separated image signals for designating gradations for a plurality of color components and a plurality of white components from an input image signal for designating gradations of a plurality of primary color components for each pixel;
The color components and the monochromatic images of the white components are separated in each of the plurality of subfields in one frame so that the subfields corresponding to the plurality of white components are separated from each other on the time axis. A display means for sequentially displaying images based on image signals. The display device according to claim 1, wherein the display unit displays a monochrome image of a white component in each subfield before and after the plurality of subfields that display the monochrome images of the plurality of color components. The display device according to claim 1, wherein the display unit displays a monochromatic image of a white component in a subfield of a gap between a plurality of subfields displaying the monochromatic image of the plurality of color components. The display device according to claim 1, wherein the display unit displays a black image in a predetermined period within one frame. The display device according to claim 4, wherein the display unit displays a black image in a last period in one frame. The display means displays a monochromatic image of at least one white component of the plurality of white components in a subfield of a longer time than a subfield displaying the monochromatic image of each color component. The display device according to any one of 5. The display device according to claim 1, wherein the separation unit generates the separated image signal by including a mixed color component of two colors of the plurality of primary color components in the plurality of color components. The display device according to claim 1, wherein the display unit includes a liquid crystal device in which OCB mode liquid crystal is sealed in a gap between the first substrate and the second substrate.   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 a plurality of color components and a plurality of white components is generated,
The color components and the monochromatic images of the white components are separated in each of the plurality of subfields in one frame so that the subfields corresponding to the plurality of white components are separated from each other on the time axis. A display device driving method for sequentially displaying images on a display device based on image signals.

Images