JP2010096894A - Display device and driving method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a color breakup phenomenon caused when driving a display device using a self-luminous element typically a lamination type organic EL element, by a time-splitting method. <P>SOLUTION: The display device includes a panel including a plurality of pixels, each of which has an element for causing one pixel to emit light in a plurality of basic colors in the order of time. The display device includes a brightness information generation part for determining a color common to a plurality of adjacent pixels that are adjacent to each other on the panel, from among the display colors of each pixel, and outputting it as a signal of the brightness for each of the basic colors, and a difference extraction part for outputting the difference between the display color of each pixel and the common color as a signal of the brightness for each of the basic colors. The display device arranges the signals of the brightness for each of the basic colors output from the respective parts in the order of time such that, among the plurality of the adjacent pixels, the order of colors of the basic colors is different from each other, and, in each of a plurality of field periods into which one frame period is divided, sends the signals of the brightness for each of the basic colors arranged in the order of time to the panel to cause a plurality of the pixels to emit light. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a display device and a driving method thereof, and more particularly to a display device such as a flat panel display using a self-luminous device typified by an organic EL element and a driving method thereof.

  In recent years, organic electroluminescence elements (organic EL elements), which are self-luminous devices, have attracted attention as flat panel displays. Organic EL elements can be thinned without the need for a backlight, and have a wide visibility and color reproduction range. Therefore, R & D activities are being conducted from various angles toward commercialization as an ideal display device. It has been broken. At present, organic EL elements have already been put into practical use as display elements for displays such as in-vehicle components and mobile phones.

  In general, an organic EL element includes an organic EL element substrate having an organic EL layer on a substrate (for example, glass or film) in which an organic light emitting layer is sandwiched between a pair of electrodes composed of an anode and a cathode facing each other. And a structure in which a sealing layer is provided on the outer surface thereof. A transparent electrode such as ITO (Indium Tin Oxide) is used as the electrode on the light extraction side of the pair of electrodes so that the light from the organic light emitting layer can be extracted to the outside. In this configuration, the organic EL element emits light when an electric current is passed between the pair of electrodes by an external drive circuit.

  As a method for realizing so-called color display in an organic EL panel composed of an organic EL element group, organic EL elements that can emit light in R (red), G (green), and B (blue) are arranged in parallel on the same plane. There is a space division display method in which each display color is arranged and mixed color is displayed. This method has also been used in conventional CRTs and liquid crystal displays.

  However, when the elements are arranged in such a configuration, since one color pixel is displayed with three dots of R, G, and B, there is a problem that the resolution is lowered.

  On the other hand, Patent Document 1 proposes a time-division drive (plane sequential drive) method in which organic EL elements are stacked and colors are mixed by repeating light emission of a plurality of colors in a short time from the same pixel area. Has been. That is, one frame period is sequentially turned on in a plurality of single color field periods, and the colors are temporally mixed to form an image of one frame.

  In the time division drive method, since the same pixel sequentially displays each R, G, and B color, one pixel is divided into R, G, and B subpixels as in a general space division display method. This is a method that is particularly advantageous when a small display or a high-resolution display is manufactured.

  Further, in Patent Document 2, there is also a proposal for improving the short life of a blue material, which is one of the problems of organic EL, by performing display combining the above-described space division display method and time division display method. .

  As described above, it has been explained that the time-division driving method is advantageous as a high-resolution display, but in reality there is a color breakup phenomenon as a big problem. The color breakup phenomenon is a phenomenon that occurs due to a relative positional shift between the display on the screen and the observer's line of sight in time division driving, and occurs because the divided images do not overlap on the observer's retina. Regarding this phenomenon, a liquid crystal display example is detailed in Patent Document 3 and the like.

Such a color breakup phenomenon has been reduced by various methods so far in liquid crystal displays and the like. The visibility of color breakup is related to the field switching display speed, the brightness of the display field, the saturation of the display field, and the like. For example, when the field switching speed is increased, the above-described line-of-sight and display misalignment that occurs between the fields is small, making it difficult to view. Further, even when the field switching speed is not high, it is difficult to visually recognize even when the luminance of each pixel in the display field is small. In addition, when a vivid color is suppressed in the field display (when the saturation is lowered), the color breakup is reduced. About this method, as also in Patent Document 4, it is possible to reduce the color breakup phenomenon by inserting achromatic fields such as white and black.
International Publication No. 2004/051614 Pamphlet Japanese Patent Laid-Open No. 2005-174639 Japanese Patent No. 3996178 Japanese Patent Application Laid-Open No. 2002-229531

  An object of the present invention is to provide a display device that reduces a color breakup phenomenon that occurs when a display device using a self-luminous element typified by a stacked organic EL element is driven in a time-division manner, and a driving method thereof. .

  In order to achieve the above object, a display device according to the present invention includes a panel including a plurality of pixels, and each of the plurality of pixels emits a plurality of basic colors according to time. A common color information generating unit that determines a color common to the plurality of neighboring pixels from a display color that each pixel displays in one frame period, and outputs it as a luminance signal for each basic color Determining a difference between the display color displayed by each pixel in one frame period and the common color and outputting the difference as a luminance signal for each basic color; and luminance for each basic color of the common color Are arranged in order of time so that the color order of the basic colors is different between the plurality of neighboring pixels, and the luminance signal for each basic color of the difference is the color of the basic color between the plurality of neighboring pixels. Time so that the order is different from each other A control unit that sequentially outputs a luminance signal for each basic color of the common color and a luminance signal for each basic color of the difference arranged in time order in each of a plurality of field periods divided into one frame period; And a driver for sending a signal output from the control unit to the panel to cause the plurality of pixels to emit light.

  The present invention also provides a method for driving a display device having a panel including a plurality of pixels, wherein each of the plurality of pixels emits a plurality of basic colors according to time, and a plurality of adjacent pixels adjacent to each other on the panel. A color common to the plurality of adjacent pixels is determined from display colors displayed by each pixel in one frame period, and is output as a luminance signal for each basic color, and the color common to the display color of each pixel Is output as a luminance signal for each basic color, and the luminance signal for each basic color of the common color is output so that the color order of the plurality of basic colors is different from each other in the plurality of adjacent pixels. Each of the plurality of field periods divided by one frame period is arranged in order, the luminance signals for the basic colors of the differences are arranged in time order so that the color orders of the plurality of basic colors are different from each other in the plurality of neighboring pixels. And the time Sequentially output a luminance signal for each basic color of the common colors and a luminance signal for each basic color of the difference, and send the luminance signal to the panel in each of the field periods. It is characterized in that light is emitted sequentially with the luminance for each basic color of the common color and the luminance for each basic color of the difference.

  ADVANTAGE OF THE INVENTION According to this invention, the display apparatus which reduces the color-breaking phenomenon which arises when the display apparatus using the self-light-emitting element represented by the lamination type organic EL element is time-division driven, and its drive method can be provided. .

  Hereinafter, embodiments of a display device and a driving method thereof according to the present invention will be specifically described with reference to the drawings.

[First Embodiment]
FIG. 1 is a display device according to a first embodiment of the present invention, and shows a pixel configuration of an organic EL display device using stacked organic EL elements.

  A TFT (Thin Film Transistor) circuit layer 102 is disposed on the glass substrate 101. On the TFT circuit layer 102, a planarizing layer 103 and an electrode layer 110 below the lowermost organic EL layer 104 are disposed. The planarization layer 103 is an electrically insulating film provided to alleviate the unevenness of the TFT circuit layer 102 and improve the yield of subsequent process steps, and is usually formed using an acrylic resin or the like.

  On the electrode 110, the lowermost organic EL layer 104 is disposed. On the organic EL layer 104, the upper electrode layer 109 of the organic EL layer 104 is disposed.

  On the electrode layer 109, a second organic EL layer 105, an electrode layer 108, a third (uppermost) organic EL layer 106, and an electrode layer 107 are disposed.

  In this manner, three layers of organic EL elements are stacked. Each electrode layer 107, 108, 109, 110 is connected to the wiring of the TFT circuit layer 102 by through-hole processing.

  Each organic EL layer includes an organic EL layer 104 that emits red (hereinafter, R) of three basic colors (red, green, and blue), an organic EL layer 105 that emits green (hereinafter, G), and blue. (Hereinafter referred to as B) and the organic EL layer 106 that emits light. The display color of the pixel can be determined depending on which of the three organic EL layers 104, 105, and 106 is lit.

  In the case of the element as described above, in order to drive all the layers independently or simultaneously, a pixel circuit capable of separately setting and outputting the driving signal of each layer is necessary. However, since the area per pixel is limited due to high definition of the display, it is not practical to construct a large-scale pixel circuit. Therefore, field sequential driving is generally performed in which one pixel circuit is switched to each layer by a switch and is not driven independently.

  Next, a driving method in the case of three basic colors (R, G, B) will be described with reference to FIGS.

  FIG. 2 is a diagram showing the output colors of the adjacent three pixels 1-3 when displaying an image of one frame, and is a characteristic part of the present embodiment. The pixels 1 to 3 shown in the figure are three adjacent pixels (proximity pixels) on the screen (panel), and, for example, an arrangement relationship as shown in FIG. 3 can be considered. The hatched portion in FIG. 3A is an example of three pixels that are closest to each other, and the hatched portion in FIG. 3B is an example of three pixels that are in contact with each other side by side.

  The “three pixels” in the present embodiment is not limited to this, and the pixel is not a square lattice shape, but can also be applied to a triangular lattice shape or other pixel arrangements. Any device that takes three adjacent pixels may be used.

  In FIG. 2, the arrangement of RGB in the vertical direction indicates the colors of three pixels in the six display fields in the period from t1 to t7.

  In the first field starting from time t1, pixel 1 is B, pixel 2 is R, and pixel 3 is G (the leftmost column among the six columns in the figure). When time advances and the second field is reached at the next time t2, pixel 1 is R, pixel 2 is G, and pixel 3 is B. Similarly, time advances and six frames pass until time t7, thereby forming one frame of a display image.

  FIG. 4A shows the luminance of the pixel 1-3 in these six fields.

  F1 to F6 in the figure indicate six fields constituting one frame of the display image. Each pixel 1 to 3 outputs only a single color determined from among the three RGB colors in one field according to FIG. The vertical bands of RGB in the figure indicate the respective display colors and the luminance at that time.

The image data of the display image is given in units of frames. The luminance of each RGB color that each pixel must display in one frame period is shown as “display color” on the rightmost side in FIG. In the example of the figure, the luminance L different color of RGB3 colors constituting the display color, the pixel 1 is _{L R1,} L _{G1, L B1,} pixels 2 _{L R2,} L _{G2, L B2,} pixels 3 _{L R3} , L _G3 , and L _B3 .

  First, in the first three fields F1 to F3, each pixel has one color common to the pixels 1 to 3 (shown in FIG. 4B. How to determine this color will be described later) is changed to RGB three colors. Divided and displayed in the time-ordered fields. Since the color order of the pixels 1-3 is shifted one by one as shown in FIG. 2, the temporal color mixture of the colors displayed in the fields F1 to F3 by each pixel and the color emitted by the three pixels in each field Spatial color mixing coincides.

In FIG. 4B, RGB of the common colors of the pixels 1 to 3 are represented by R ₀ , G ₀ and B ₀ , and the luminance L for each color is represented by L _R0 , L _G0 and L _B0 .

  In the latter three fields F4 to F6, the pixels 1 to 3 represent the difference between the display color shown at the right end in FIG. 4A and the common color in FIG. Is output in a time-sharing manner for each color brightness.

The luminance information of this difference is also arranged and output so that the time order is different in the pixels 1-3. The luminance L in F4 to F6 for displaying the difference is in the order of F4, F5, and F6, the pixel 1 is L _B1 -LB ₀ , L _R1 -LR ₀ , LG ₁ -LG ₀ , and the pixel 2 is L _R2 -LR ₀ , L _{G2 -L G0, L B2 -L B0} , pixel 3 is _{L G3 -L G0, L B3 -L} B0, L R3 -L R0.

The common colors in FIG. 4B are the three RGB colors L _R0 , L _G0 , and L _B0 as large as possible, so that the pixels 1 to 3 output in the latter three fields F4 to F6 The luminance of the difference can be reduced. If the difference can be reduced, it is possible to avoid high luminance in the latter three fields where different colors are displayed.

  On the other hand, in the first three fields F1 to F3, when three pixels are spatially combined, each field emits light in the same color, so that it is sensed that the same color continues in time. For this reason, color breakup does not occur.

  Next, a specific method for determining the common color of the adjacent pixels 1 to 3 will be described.

The first method is the simplest, and in each of the adjacent pixels 1 to 3, the smallest minimum luminance L _Rmin , L _Gmin , L _Bmin is selected from the luminance of each color for each of the three RGB colors, and the color of the common color is selected. It determines as another brightness _| luminance _LR0 , _LG0 , _LB0 .

In the second method, from the viewpoint of using spatial information, the average luminance L _Ravg , L _Gavg , L is calculated for each of the adjacent pixels 1 to 3 by calculating the average luminance of each color of RGB. _Bavg is determined as the luminance L _R0 , L _G0 , and L _B0 for each common color.

The third method targets not only the adjacent pixels 1 to 3 but also a wider range, for example, not only display pixels (shaded portions) as shown in FIG. That is, the method in the pixel of each pixel 1-3 and around adjacent, to another RGB3 colors colors, to calculate the average of each color brightness of an average luminance _{L Ravg, L Gavg, L Bavg} common color The luminances L _R0 , L _G0 , and L _B0 are determined for each color.

  Operations such as averaging by the second and third methods represent a change in resolution.

In the fourth method, for example, instead of taking the average of four pixels, a low-resolution image having a resolution that is a quarter of the resolution of the original image is created. Then, the luminance of each of the three RGB colors corresponding to the corresponding low-resolution image is determined as the luminance L _R0 , L _G0 , and L _B0 of each common color. The resolution of the low-resolution image is not limited to one-fourth of the resolution of the original image, and may be any one-half of the resolution of the original image, one-third, or the like.

In the second and third methods, the luminances L _R0 , L _G0 , and L _B0 of the common colors are determined by the averaging operation, so that the luminance of any one of the common colors RGB should be originally displayed. It may be larger than the color brightness. In this case, the difference luminance obtained by subtracting the luminance of each color of the common color from the luminance of each color of the display color becomes negative and cannot be displayed.

  In order to prevent negative difference luminance, the luminance of each color of the common color cannot be made larger than the necessary luminance of each color of the display color. Therefore, by comparing the brightness of each color of the common color and the required brightness of each color of the display color, if the brightness of each color of the common color is larger than the required brightness of each color of the display color, the required brightness of each color of the display color is Displayed as the brightness of each common color. This is shown in FIG.

In FIG. 5A, in the first field period F1, there is no problem because the luminance of each common color is lower than the required luminance of each color of the display color in each of the pixels 1 to 3. However, in the second field period F2, the luminance L _R0 of R (R ₀ ) of the common color (see FIG. 5B) is higher than the required luminance L _R1 of the display color R (R ₁ ) of the pixel 1. Is bigger. For this reason, the luminance of the common color R (R ₀ ) is reduced to the required luminance L _R1 of the display color R (R ₁ ) in the pixel 1 (see the hatched portion in the figure). As a result, the chromaticity is slightly shifted in the display in the second field period F2, but in the case of a continuous image such as a natural image, each color of the average luminance and the display color used as an example of the luminance of each color of the common color. Therefore, the required luminance of the image does not greatly deviate so that color breakup does not occur.

  In the above description, among the six field periods F1 to F6 constituting one frame period of the display image, the first three field periods F1 to F3 are output as a common color, and the latter three field periods F4 to F6. Is the period for outputting the difference. However, even in the opposite case, the effect on color breakup does not change. In addition, when the common color and the difference color are output alternately, the field period for outputting the common color with low saturation can be sandwiched between the field periods for outputting the difference that may have high saturation. Further, it is possible to further suppress the color breakup during the field period in which the difference is output.

  FIG. 10 is an example of a display device provided with color breakage reducing means for realizing the above driving method.

  The display device shown in the figure is an organic EL display device having, as pixels, elements that emit a plurality of basic colors (R, G, B) according to time as shown in FIG. The display device includes a flat display panel (hereinafter referred to as a panel) 10 in which pixels are arranged, a driver 11 that drives the panel 10, and color breakage reduction means 12 that controls the operation of the driver 11. The driver 11 and the color breakage reducing means 12 constitute a drive circuit for the display device of the present invention.

  The color breakage reducing means 12 includes a common color information generation unit 13, a first frame memory 14, a difference extraction unit 15, a common color information field configuration unit 16, a difference information field configuration unit 17, a second frame memory 18, and a field control unit. 19 is provided.

  The common color information field configuration unit 16 and the difference information field configuration unit 17 correspond to a field signal generation unit.

The common color information generation unit 13 inputs image data of a display image, and from the display colors displayed by a plurality of (for example, three) adjacent pixels adjacent on the panel 10, a color common to those pixels (common color) And the luminance information is generated. The luminance information is composed of a set of luminance values for each basic color, (L _R , L _G , L _B ). The common color determination method is the above-described first to fourth methods or the like.

  The difference extraction unit 15 generates difference information between the display color displayed by each pixel and the common color determined by the common color information generation unit 13. This difference information is also composed of a set of luminance differences for each basic color of the display color and the common color.

  The common color information field configuration unit 16 receives the luminance information of the common color from the common color information generation unit 13 and generates a luminance signal for each field in the determined basic color order. That is, a luminance signal (common color field signal) for each basic color is output in each field period. The number of field periods is equal to the number of basic colors or an integer multiple thereof.

  Further, the common color information field configuration unit 16 performs control to shift the color order for each pixel so that the color order of the basic colors is different between adjacent pixels.

  Similarly, the difference information field configuration unit 17 receives the difference information from the difference extraction unit 15 and generates a luminance signal for each field. That is, the luminance signal (difference field signal) of each basic color is output in each field period. The number of field periods is also equal to the number of basic colors or an integer multiple thereof, but is not necessarily the same as the number of common color field periods.

  Further, the difference information field configuration unit 17 also performs control to shift the field order for each pixel so that the color order of the basic colors is different between adjacent pixels. However, the color order is not necessarily the same as the color order of the common color field signal.

  The field control unit 19 assigns the common color field signal received from the common color information field configuration unit 16 to the first half of the field periods constituting one frame period. At the same time, the difference field signal received from the difference information field configuration unit 17 is allocated to the latter half of the plurality of field periods constituting one frame period, excluding the field period to which the common color field signal is allocated. A signal for each field period is sent to the driver 11.

  The order of the common color field period and the difference field period may be reversed, that is, the difference field signal may be sent in the first half field period of one frame period, and the common color signal may be sent in the second half field period.

  The common color information field configuration unit 16, the difference information field configuration unit 17, and the field control unit 19 generate signals in time order and cause the pixels to emit light according to basic colors, and thus form the center of the display device of the present invention. These are collectively referred to as a control unit.

  The driver 11 sends a field signal from the field control unit 19 to the panel 10 to cause each pixel to emit light.

  The display device having the above configuration will be described as a driving method.

  First, the common color information generation unit 13 generates luminance information of one color common to the plurality of adjacent pixels from the display colors displayed by the plurality of adjacent pixels adjacent to each other on the panel. The luminance information of the common color is given as a luminance set for each of a plurality of basic colors.

  Next, the difference extraction unit 15 generates difference information between the display color displayed by the plurality of adjacent pixels and the common color for each of the plurality of basic colors.

  In response to the luminance information of the common color and the difference, the control unit (17, 18, 19) causes each of the plurality of adjacent pixels to emit light via the driver 11. In this light emission, each pixel changes the color order of a plurality of basic colors. First, the luminance information of the common color is emitted in a time division manner to display the common color, and then the difference information is time-division emitted to obtain the difference information. Display color.

  The control unit configures one frame image with a plurality of fields, with one light emission as one field. As the plurality of field signals, a common color field signal generated by the common color information field configuration unit 16 and a difference field signal generated by the difference information field configuration unit 17 are used. That is, a set of a plurality of pixels, a field signal for outputting a common color displayed on all of the plurality of pixels, and a field signal for outputting a difference between the common color and the display color to be displayed by each pixel. By sequentially outputting, one frame image is formed.

  According to the present embodiment, the field image to be displayed in a time-division manner can be determined from the two-dimensional color and luminance information of the image to be displayed. As a result, it is possible to avoid a field with high saturation and brightness that is visually recognized by color breakup unrelated to the display image, and to perform natural display. In particular, in a display using a stacked organic EL element, color breakup when performing field sequential driving can be significantly suppressed.

  As described above, the common color (the luminance information for each common color having the same luminance and the same luminance) is determined by the display colors of the plurality of neighboring pixels or the display colors of the plurality of neighboring pixels and the surrounding pixels. For example, the minimum value of the luminance information for each basic color may be selected from the display colors of a plurality of adjacent pixels, and the minimum value may be determined as the luminance for each basic color of the common color. Alternatively, the average luminance information may be determined including the average value of the luminance of the basic colors of the display colors of the plurality of adjacent pixels, or the plurality of adjacent pixels and the surrounding pixels, and may be used as the luminance information of the common color. . In addition, a low-resolution image of a display image may be created in a plurality of adjacent pixels, and luminance information for each color of the low-resolution image may be determined as common luminance information for the same color and the same luminance.

  Further, the driving method of the display device according to the present embodiment is to drive each pixel of a flat panel display constituted by an element capable of emitting one pixel in a plurality of basic colors in the following steps.

  (Step A1) The brightness of each basic color common to a plurality of adjacent pixels on the panel is determined, and light is emitted sequentially by time division for each basic color.

  (Step A2) A difference between the luminance of each basic color of the color that each pixel should display in the period of one frame, that is, the display color, and the luminance of each basic color of the common color determined in Step A1 is obtained. The light is emitted sequentially in time division for each basic color.

  Since one of the basic colors is emitted in one field, step A1 is executed for the number of basic colors, and step A2 is executed for the same number of fields, thereby completing one frame image.

  The driving method of the display device according to the present embodiment may include the following steps.

  (Step B1) When a certain pixel performs display, the color and luminance information to be output are determined from the peripheral color and luminance information of the pixel to be output from the pixel.

  (Step B2) The pixels are sequentially emitted to a plurality of basic colors by time division. In this step of emitting light, one light emission is defined as one field, and one frame image is composed of a plurality of fields.

  Still another driving method of the display device of this embodiment includes the following steps.

  (Step C1) A low-resolution image of the image (original image) to be displayed is constructed, and the color and luminance information of one pixel of the low-resolution image is displayed adaptively to a plurality of corresponding pixels on the original image. Let

  (Step C2) The difference between the required luminance of each color of the original image and the color and luminance information displayed in the previous step is displayed. One step of the display is one field, and one frame image is composed of a plurality of fields.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIGS.

  In the first embodiment, a case has been described in which three colors of R, G, and B are used as a plurality of basic colors constituting the display color of an image. However, in this embodiment, R, G, and B are used. Of these three colors, two colors are combined.

  FIG. 6 shows an outline of a pixel configuration in a panel structure of an organic EL display device having two layers of stacked organic EL elements used in the display device according to the present embodiment. The element shown in the figure shows a structure in which organic EL elements are stacked in two layers. A TFT circuit layer 202 is disposed on the glass substrate 201. On the TFT circuit layer 202, two electrode layers 210 and 213 adjacent to the planarization layer 203 are disposed. The planarization layer 203 is an electrically insulating film provided to alleviate the unevenness of the TFT circuit layer 202 and improve the yield of subsequent process steps, and is usually formed using an acrylic resin or the like. Lower organic EL layers 204 and 207 are disposed on the two electrode layers 210 and 213, respectively. Upper electrode layers 209 and 212 are disposed on the organic EL layers 204 and 207, respectively. On the electrode layers 209 and 212, the upper organic EL layers 205 and 206 and the electrode layers 208 and 211 are disposed, respectively. In this way, two layers of organic EL elements are stacked. Each of the electrode layers 208 to 213 is connected to a predetermined wiring of the TFT circuit layer 202 by through-hole processing.

  In general, a display uses three colors such as RGB in order to display a predetermined color space. For this reason, since the two-layer organic EL element displays two colors, when two or more adjacent elements are used as one pixel, three or more colors are displayed. As a method for configuring colors, for example, a combination in which the organic EL layers 205 and 206 are formed as the same B light emitting layer and GB and RB are used is preferable. The reason is that, generally, the organic EL element tends to have a short lifetime of the blue element (B), so that the luminance can be reduced and the load can be reduced by increasing the area of B.

  FIG. 7 shows the output color of each pixel when displaying an image of one frame, which is a characteristic part of the present embodiment. The pixel 1 and the pixel 2 are two adjacent pixels (proximity pixels) on the screen. For example, the arrangement relationship shown in FIG. 8 can be considered. The hatched portion in FIG. 8A is an example of two pixels that are adjacent obliquely, and FIG. 8B is an example of two pixels that are in contact with each other side by side. The “two pixels” in the present embodiment is not limited to this, and the pixel is not a square lattice shape, but can be applied to a triangular lattice shape or other pixel arrangements. In short, as many as possible among a plurality of pixels on the panel. What is necessary is just to take two adjacent pixels.

  In FIG. 7, the arrangement of BG and RB in the vertical direction indicates two pixels in the display field at a certain time. When the pixel 1 is BG and the pixel 2 is RB in the field at a certain time t1 (the leftmost column among the four columns in the figure), when the time advances and the field at the next time t2 is reached, the pixel 1 RB and pixel 2 are BG. Similarly, time advances and four frames elapse to form one frame. The function of these four fields is shown in FIG.

In FIG. 9A, each of the pixels 1 and 2 outputs two of the three RGB colors simultaneously. F1 to F4 in the figure indicate four fields constituting one frame of the display image. The vertical bands of RGB in the figure indicate the respective display colors and the luminance at that time, as in the first embodiment. Since each pixel can display two colors simultaneously in the same field, a two-color band is included. The R, G, and B display patterns that each pixel must display as image data are shown as “display colors” on the leftmost side of the drawing. In the example in the figure, the luminance L of R, G, and B constituting the display color is represented by L _R1 , L _G1 , L _{B1 for} the pixel ₁ , and L _R2 , L _G2 , L _B2 for the pixel 2.

First, in the first two fields F1 to F2, the luminances of the three colors RGB of the common colors (see FIG. 9B) of the pixels 1 and 2 are displayed. This is determined so that the temporal color mixture after each pixel displays the fields F1 to F2 and the spatial color mixture obtained by simultaneously emitting two pixels (four colors) in each field are the same. In the example in the figure, RGB of common colors of the pixels 1 and 2 are represented by R ₀ , G ₀ , and B ₀ , and the luminance L for each color is represented by L _R0 , L _G0 , and L _B0 . Details of the method for determining the common color of the pixels 1 and 2 will be described later.

In the latter two fields F3 to F4, the luminance L of the RGB three colors of the display color that each pixel 1 and 2 must display and the RGB three colors (R ₀ , R) of the common color (see FIG. 9B). The luminance L of the difference for each color from the luminance L of G ₀ , B ₀ ) is output. In the example in the figure, the luminance of Color difference L, the pixel 1 is _{L R1 -L R0, L G1 -L} G0, L G1 -L G0, pixel 2 _{L R2 -L R0, L G2 -L} G0 , L _G2 -L _G0 .

Here, the luminance L _R0 , L _G0 , and L _B0 of the RGB three colors of this common color (see FIG. 9B) is set as large as possible, so that the luminance of the difference output in the latter two fields F3 to F4 is obtained. Can be reduced. If the difference can be reduced, it is possible to avoid the output of high-saturation fields with high luminance, so that color breakup can be reduced. On the other hand, in the first two fields F1 to F2, the two pixels emit different colors by changing the color order in time division, but at the same time, the two pixels emit light at the same color ratio in each field. Therefore, it is perceived that the same color continues when viewed spatially. For this reason, color breakup does not occur as in the case of the first embodiment.

  Next, a method for determining a common color for the adjacent pixels 1 and 2 will be described.

The first method is the simplest, and in each of the adjacent pixels 1 and 2, the smallest minimum luminance L _Rmin , L _Gmin , L _Bmin among the luminances of each color is selected for each color of RGB, and the color of the common color is selected. It determines as another brightness _| luminance _LR0 , _LG0 , _LB0 .

In the second method, from the viewpoint of using spatial information, the average luminance L _Ravg , L _Gavg , L L is calculated for each of the adjacent pixels 1 and 2 by calculating the average luminance of each color of RGB. _Bavg is determined as the luminance L _R0 , L _G0 , and L _B0 for each common color.

The third method targets not only the adjacent pixels 1 to 3 but also a wider range, for example, not only display pixels (shaded portions) as shown in FIG. That is, the method in the pixel of each pixel 1-3 and around adjacent, to another RGB3 colors colors, to calculate the average of each color brightness of an average luminance _{L Ravg, L Gavg, L Bavg} common color The luminances L _R0 , L _G0 , and L _B0 are determined for each color.

Operations such as averaging by the second and third methods represent a change in resolution. For this reason, the fourth method creates a low-resolution image whose resolution is, for example, one-fourth of the resolution of the original image, instead of taking the average of four pixels, for example. Then, the luminance of each of the three RGB colors corresponding to the corresponding low-resolution image is determined as the luminance L _R0 , L _G0 , and L _B0 of each common color. The resolution of the low-resolution image is not limited to one-fourth of the resolution of the original image, and may be any one-half of the resolution of the original image, one-third, or the like.

Further, regarding the display of the color B in FIG. 9A, in order to display the common color (FIG. 9B) in the pixel 1 and the pixel 2, half of the luminance L _G0 of the common color B is set to the pixel 1 It is desirable to display 2 evenly. As a result, the display of both pixels becomes equivalent, and no color breakup or color shift occurs.

  In the above description, out of the four fields F1 to F4 constituting one frame of the display image, the first three fields F1 to F2 are fields for outputting a common color, and the latter three fields F3 to F4 are output as differences. To be a field. However, even in the opposite case, the effect on color breakup does not change. In addition, when a common color and a difference color are output alternately, a field that outputs a common color with low saturation can be sandwiched between fields that output a difference that may have high saturation. Can be further suppressed.

  The present invention has been described above with reference to the embodiment. However, the present invention is not limited to the above embodiment, and the configuration and details of the present invention will be understood by those skilled in the art within the scope of the present invention. Various changes can be made.

  The present invention can be used for a display device such as a flat panel display using a self-luminous device typified by an organic EL element and a driving method thereof.

It is the schematic explaining the pixel structure of the organic electroluminescent display used with the display apparatus which concerns on the 1st Embodiment of this invention. In the display apparatus shown in FIG. 1, it is a figure explaining the time change of the display color in 1 frame display of predetermined 3 pixels. FIG. 2 is a diagram showing an arrangement of predetermined three pixels on a display panel in the display device shown in FIG. 1. In the display apparatus shown in FIG. 1, it is a figure explaining the relationship of each field which predetermined 3 pixels display. In the display apparatus shown in FIG. 1, it is a figure explaining the relationship of each field which predetermined 3 pixels display. It is the schematic explaining the pixel structure of the organic electroluminescent display used with the display apparatus which concerns on the 2nd Embodiment of this invention. FIG. 7 is a diagram for explaining a temporal change in display color in one frame display of predetermined two pixels in the display device shown in FIG. 6. FIG. 7 is a diagram showing an arrangement of predetermined two pixels on a display panel in the display device shown in FIG. 6. FIG. 7 is a diagram illustrating a relationship between fields displayed by two predetermined pixels in the display device illustrated in FIG. 6. It is a schematic block diagram which shows the structure of the display apparatus which concerns on the 1st, 2nd embodiment of this invention.

Explanation of symbols

10 Panel 11 Driver 12 Color Breaking Reduction Unit 13 Common Color Information Generation Unit 14 First Frame Memory 15 Difference Extraction Unit 16 Difference Information Field Configuration Unit 17 Common Color Information Field Configuration Unit 18 Second Frame Memory 19 Field Control Unit

Claims (7)

A display device having a panel including a plurality of pixels, wherein each of the plurality of pixels emits a plurality of basic colors according to time;
Common color information for a plurality of adjacent pixels adjacent to each other on the panel, determining a color common to the plurality of adjacent pixels from display colors displayed by each pixel in one frame period, and outputting as a luminance signal for each basic color Generating part,
A difference extraction unit that determines a difference between the display color displayed by each pixel in one frame period and the common color, and outputs the difference as a luminance signal for each basic color;
The luminance signals for the basic colors of the common colors are arranged in time order so that the color order of the basic colors is different between the plurality of adjacent pixels, and the luminance signals for the basic colors of the differences are The luminance signals for the basic colors of the common colors arranged in the time order in each of a plurality of field periods divided into one frame period in the order of time so that the color order of the basic colors is different between adjacent pixels And a controller that sequentially outputs a luminance signal for each basic color of the difference,
A driver for sending a signal output from the control unit to the panel to emit light from the plurality of pixels;
A display device comprising:   The common color information generation unit outputs a minimum value of the luminance for each basic color of the display color among the plurality of adjacent pixels as a luminance for each basic color of the common color. Item 4. The display device according to Item 1.   The common color information generation unit outputs an average value of the luminance for each basic color of the display color among the plurality of adjacent pixels as luminance for each basic color of the common color. Item 4. The display device according to Item 1.   The common color information generation unit creates a low-resolution image of a display image in the plurality of adjacent pixels, and outputs the luminance for each basic color of the low-resolution image as the luminance for each basic color of the common color. The display device according to claim 1, characterized in that:   5. The display device according to claim 1, wherein the plurality of basic colors are three colors of R, G, and B. 6.   6. The display device according to claim 1, wherein the plurality of basic colors are a combination of two of the three colors R, G, and B. 6. A driving method of a display device having a panel including a plurality of pixels, wherein each of the plurality of pixels emits a plurality of basic colors according to time,
For a plurality of adjacent pixels adjacent to each other on the panel, a color common to the plurality of adjacent pixels is determined from display colors displayed by each pixel in one frame period, and output as a luminance signal for each basic color,
The difference between the display color of each pixel and the common color is output as a luminance signal for each basic color,
The luminance signals for the basic colors of the common colors are arranged in time order so that the color order of the plurality of basic colors is different from each other in the plurality of neighboring pixels,
The luminance signals for each basic color of the difference are arranged in time order so that the color order of the plurality of basic colors is different from each other in the plurality of adjacent pixels,
In each of a plurality of field periods obtained by dividing one frame period, a luminance signal for each basic color of the common color and a luminance signal for each basic color difference arranged in time order are sequentially output, The display device driving method according to claim 1, wherein the luminance signal is sent to the panel, and the pixels are caused to emit light sequentially with the luminance for each basic color of the common color and the luminance for each basic color of the difference.