JP2005234486A - Device and method for driving light self-emissive display panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device and method for driving a light self-emissive display panel capable of suppressing a decrease in moving picture resolution and moving picture false outline disturbance of an active matrix type display panel having light self-emissive elements arrayed in matrix, and dispersing noise due to the moving picture false outline disturbance. <P>SOLUTION: The driving device for the active matrix type display panel equipped with a plurality of organic EL elements 14 which are arranged at intersections of a plurality of data lines and a plurality of scanning lines and brought under light emission control at least each through an illumination driving TFT 12, is equipped with a 1st gradation control means of dividing a frame period into a plurality of sub-frame periods with time and weighting one or a plurality of sub-frame periods as a group to set illumination periods of respective pixels and a 2nd gradation control means of operating in a predetermined illumination period controlled by the 1st gradation control means and performing turn-off control over some pieces in each group while grouping a plurality of adjacent pixels into one. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a driving device and a driving method for a self-luminous display panel that performs gradation expression by time-dividing one frame period into a plurality of subframe periods and controlling lighting of each subframe period.

  The development of a display using a display panel configured by arranging light emitting elements in a matrix is being widely promoted. As a light-emitting element used in such a display panel, for example, an organic EL (electroluminescence) element using an organic material for a light-emitting layer has attracted attention.

  As a display panel using such an organic EL element, there is an active matrix display panel in which an active element made of, for example, a TFT (Thin Film Transistor) is added to each of the EL elements arranged in a matrix. This active matrix display panel has characteristics such as low power consumption and low crosstalk between pixels, and is particularly suitable for a high-definition display constituting a large screen.

  FIG. 1 shows an example of a circuit configuration corresponding to one pixel 10 in a conventional active matrix display panel. In FIG. 1, a gate G of a TFT 11 serving as a control transistor is connected to a scanning line (scanning line A1), and a source S is connected to a data line (data line B1). The drain D of the control TFT 11 is connected to the gate G of the TFT 12 that is a driving transistor and to one terminal of the charge holding capacitor 13.

  The drain D of the driving TFT 12 is connected to the other terminal of the capacitor 13 and to the common anode 16 formed in the panel. The source S of the driving TFT 12 is connected to the anode of the organic EL element 14, and the cathode of the organic EL element 14 is connected to a common cathode 17 that forms, for example, a reference potential point (ground) formed in the panel. Has been.

  FIG. 2 schematically shows a state in which the circuit configuration responsible for each pixel 10 shown in FIG. 1 is arranged on the display panel 20, and each scanning line A1 to An, each data line B1 to Bm, and Each pixel 10 having the circuit configuration shown in FIG. 1 is formed at each of the intersection positions. In the configuration described above, each drain D of the driving TFT 12 is connected to the common anode 16 shown in FIG. 2, and the cathode of each EL element 14 is connected to the common cathode 17 shown in FIG. It is set as the structure. In this circuit, when the light emission control is executed, the switch 18 is connected to the ground as shown in the figure, whereby the voltage source + VD is supplied to the common anode 16.

  In this state, when the ON voltage is supplied to the gate G of the control TFT 11 in FIG. 1 via the scanning line, the TFT 11 supplies a current corresponding to the voltage from the data line supplied to the source S to the drain D. Shed. Therefore, the capacitor 13 is charged while the gate G of the TFT 11 is on-voltage, the voltage is supplied to the gate G of the driving TFT 12, and the TFT 12 is supplied with a current based on the gate voltage and the drain voltage. The EL element 14 is caused to emit light from S through the EL element 14 to the common cathode 17.

  When the gate G of the TFT 11 is turned off, the TFT 11 becomes a so-called cut-off, and the drain D of the TFT 11 is opened, but the driving TFT 12 holds the voltage of the gate G by the charge accumulated in the capacitor 13. The driving current is maintained until the next scanning, and the light emission of the EL element 14 is also maintained. Since the driving TFT 12 has a gate input capacitance, the same operation as described above can be performed without providing the capacitor 13 as described above.

  Incidentally, there is a time gradation method as a method for performing gradation display of image data using the circuit configuration as described above. In this time gray scale method, for example, one frame period is time-divided into a plurality of sub-frame periods, and halftone display is performed by accumulating the sub-frame periods emitted by the organic EL element per one frame period. Note that this time gray scale method includes a method in which EL elements are caused to emit light in sub-frame units and gray scale is expressed by the cumulative sub-frame period of light emission (referred to as a simple sub-frame method for convenience), and one or more There is a method in which the subframe periods are set as a set, and the set is weighted, and gradation is expressed by the combination (referred to as a weighted subframe method for convenience).

  However, since the time gray scale method expresses a gray scale with a combination of discrete light emission in the time direction with respect to an image of one frame, contour noise called moving image pseudo contour interference may occur. Yes, this was one cause of image quality degradation. This moving image pseudo contour interference will be described with reference to FIG. FIG. 3 is a diagram for explaining a mechanism of occurrence of moving image pseudo contour interference. In FIG. 3, an example will be described in which four sets of subframes (sets 1 to 4) weighted (weight 1, 2, 4, 8) to the power of 2 are arranged in ascending order of luminance.

  Consider an image whose luminance increases step by step in units of pixels as it goes down the display screen, that is, an image in which the luminance changes smoothly, and this image moves upward by one pixel after one frame has elapsed. As shown in the drawing, the display positions on the screen of the frame 1 and the frame 2 are shifted by one pixel, but this image movement break cannot be recognized by human eyes. However, since the human eye has a characteristic to follow the moving luminance, for example, between the luminance 7 and the luminance 8 in which the light emission pattern changes greatly due to carry, the sub-frame group that does not emit light follows. As a result, black pixels with a luminance of 0 appear to move to the human eye. Therefore, the human eye recognizes luminance that does not exist originally, and this is perceived as contour noise. As described above, when the same gradation data is displayed with the same pixel in consecutive frames, if the light emission pattern in each frame is the same, moving image pseudo contour interference is likely to occur.

  As one of countermeasures against such a problem, there is a method of changing the display order of a set of weighted subframes for each frame. In the example shown in FIG. 4, one frame is time-divided into seven subframes (SF1 to SF7), and combinations of subframes are set as set 1 (weight 4), set 2 (weight 2), and set 3 (weight 1). ) To achieve 8 gradation expression. For example, in the first frame, the display order is set 1, set 2, and set 3, but in the second frame, the display order is set 2, set 1, set 3, and the same gradation data is displayed. Also, the light emission pattern is different. That is, since the light emission pattern is different even in the same gradation data in consecutive frames, the occurrence of the moving image pseudo contour interference is suppressed to some extent.

For example, Patent Document 1 discloses a gradation display in which a light emission pattern of one frame data is devised in order to suppress the occurrence of moving image pseudo contour interference.
JP-A-2001-125529 (page 3, right column, line 45 to page 4, left column, line 9, line 2)

  According to the method shown in FIG. 4, control is performed such that the light emission patterns between consecutive frames in the same pixel are always different, and therefore, the generation of noise due to moving image pseudo contour interference can be suppressed to some extent. However, it has been found that when the same gradation data is displayed in adjacent pixels, the noise due to the moving image pseudo contour interference is more greatly enhanced if the light emission patterns in the pixels are the same. Therefore, it is desirable to consider not only the correspondence in the same pixel but also the correspondence between adjacent pixels.

  As one of countermeasures, as shown in FIG. 5, for example, an area gradation method in which gradation display of image data for one pixel is originally performed using two pixels and the time gradation method are combined. There is a way. This method will be described with reference to FIG. For example, as shown in FIG. 5A, two pixel positions A and B are associated with positions in a grid pattern on the screen. Then, as shown in FIG. 5B, the frame period during which the light emitting elements at the pixel positions A and B are driven to emit light is time-divided into four subframes (SF1 to SF4). Then, the frames corresponding to the pixel position A and the pixel position B are grouped together, and the combination of each subframe is divided into a group 1 of weight 4, a group 2 of weight 2, and a group 3 of weight 1, and 8 gradations The expression is realized. Therefore, since the light emission patterns of the frames corresponding to the pixel position A and the pixel position B are different, that is, the light emission patterns are different in adjacent pixels, noise due to the moving image pseudo contour interference is dispersed.

  In addition, as shown in FIG. 5B, when 8 gradations are displayed in two frames having different light emission drive timings, one subframe period is left, and this period is always an all pixel extinguishing period. By arranging the positions of the sub-frames in which all the pixels are turned off at different positions for each frame data, it is possible to change the light emission pattern in successive frames even when the same gradation data is displayed. As a result, the occurrence of moving image pseudo contour interference is suppressed. However, in the gradation display method shown in FIG. 5, since image data for one pixel is displayed in gradation by two pixels, there is a problem that the resolution of a moving image is naturally reduced.

  The present invention has been made paying attention to the above-mentioned technical problems. In an active matrix display panel in which self-luminous elements are arranged in a matrix, a reduction in moving image resolution is suppressed and a moving image pseudo contour interference is prevented. It is an object of the present invention to provide a driving device and a driving method for a self-luminous display panel that can suppress generation and disperse noise caused by moving image pseudo contour interference.

  The self-luminous display panel driving device according to the present invention, which has been made to solve the above-mentioned problems, is arranged at intersections of a plurality of data lines and a plurality of scanning lines as claimed in claim 1, and is lit at least each. An active matrix display panel driving device having a plurality of light emitting elements controlled to emit light via a driving transistor, wherein the frame period is time-divided into a plurality of subframe periods, and one or more subframes By weighting the frame periods as a set, each of the first gradation control means for setting the lighting period of the pixel operates in a predetermined lighting period controlled by the first gradation control means. A plurality of pixels are grouped into a group, and second gradation control means for controlling turning off one pixel in each group is provided.

  According to another aspect of the present invention, there is provided a driving method for a self-luminous display panel according to the present invention, which is arranged at intersections of a plurality of data lines and a plurality of scanning lines. A driving method of an active matrix display panel having a plurality of light emitting elements whose light emission is controlled via a lighting driving transistor, wherein a frame period is divided into a plurality of subframe periods by a first gradation control means. Each pixel lighting period is set by dividing and weighting one or a plurality of subframe periods as a set, and the second gradation control is performed in a predetermined lighting period among the lighting periods. It is characterized in that by operating the means, a plurality of adjacent pixels are made into one group, and one part of the pixels in each group is controlled to be turned off.

  A self-luminous display panel driving apparatus and driving method according to the present invention will be described below based on the embodiments shown in the drawings. In the following description, parts corresponding to those shown in FIG. 1 and FIG. 2 already described are denoted by the same reference numerals, and therefore descriptions of individual functions and operations will be omitted as appropriate.

  Further, in the conventional example shown in FIGS. 1 and 2, so-called monochromatic light emission in which the series circuit of the driving TFT 12 and the EL element 14 constituting the pixel are all connected between the common anode 16 and the common cathode 17. An example of the display panel is shown. However, in the driving method and driving device for a self-luminous display panel according to the present invention described below, each of R (red), G (green), and B (blue), as well as a monochromatic light emitting display panel, is used. The present invention is suitably employed for a color display panel provided with light emitting pixels (subpixels).

  FIG. 6 is a block diagram showing an embodiment of the driving apparatus and driving method according to the present invention. In FIG. 6, the drive control circuit 21 includes a data driver 24 (first driver), a write gate driver 25 (second driver), an erase gate driver 26, and pixels 30 arranged in a matrix. The operation of the driving means comprising the above is controlled.

  First, the input analog video signal is supplied to a drive control circuit 21 and an analog / digital (A / D) converter 22. The drive control circuit 21 generates a clock signal CL for the A / D converter 22, a write signal W for the frame memory 23, and a read signal R based on a horizontal synchronization signal and a vertical synchronization signal in the analog video signal. .

  The A / D converter 22 samples the input analog video signal based on the clock signal CK supplied from the drive control circuit 21, converts it to pixel data corresponding to each pixel, and converts the frame into a frame data. It acts to supply to the memory 23. The frame memory 23 operates to sequentially write each pixel data supplied from the A / D converter 22 to the frame memory 23 in accordance with a write signal W from the drive control circuit 21.

  When the writing of data for one screen (n rows and m columns) in the self-luminous display panel 40 is completed by such a writing operation, the memory 23 receives the read signal R supplied from the drive control circuit 21 to start from the first row to the nth row. The drive pixel data read for each row to the row is sequentially supplied to the data driver 24.

  At the same time, a timing signal is sent from the drive control circuit 21 to the write gate driver 25. Based on this, the gate driver 25 sequentially sends gate-on voltages to each scanning line as will be described later. Therefore, the drive pixel data for each row read from the memory 23 as described above is addressed for each row by the scanning of the gate driver 25. In this embodiment, a control signal is sent from the drive control circuit 21 to the erasing gate driver 26.

  The erasing gate driver 26 receives a control signal from the drive control circuit 21 and is electrically separated and arranged for each scanning line as will be described later (in this embodiment, the control lines C1 to Cn). A predetermined voltage level is selectively applied to control an on / off operation of an erasing TFT 15 described later.

  Further, the drive control circuit 21 sends a control signal to the reverse bias voltage applying means 27. The reverse bias voltage application means 27 receives the control signal, selectively applies a predetermined voltage level to the cathode 32, and supplies a forward or reverse bias voltage to the organic EL element. Operate. This reverse bias voltage is a voltage in a direction opposite to the direction in which current flows during light emission (forward direction), and is applied to each organic EL element during a period unrelated to the light emission period for displaying image data. . In addition, it is known that the light emission lifetime of the element is extended over time by applying the reverse bias voltage in this way.

  FIG. 7 is a diagram illustrating a circuit configuration example of one pixel among the pixels 30 arranged in a matrix on the self-luminous display panel 40. The circuit configuration corresponding to one pixel 30 shown in FIG. 7 is applied to an active matrix display panel. In this circuit, a TFT 15 which is an erasing transistor for erasing charges accumulated in the capacitor 13 is added to the circuit configuration of the pixel 10 shown in FIG. 1, and the source S and drain D of the lighting driving TFT 12 are further connected. A diode 19 connected so as to bypass this is added in between.

  First, the erasing TFT 15 is connected in parallel to the capacitor 13, and the organic EL element 14 is turned on in accordance with a control signal from the drive control circuit 21 during the lighting operation, so that the charge of the capacitor 13 is instantaneously changed. It can be discharged. Thereby, the pixel can be turned off until the next addressing.

  On the other hand, the diode 19 has an anode (anode) connected to the anode of the EL element 14 described above, and a cathode (cathode) of the diode 19 connected to the anode 31. Therefore, the diode 19 is connected in parallel between the source S and the drain D of the driving TFT 12 so as to be opposite to the forward direction of the EL element 14 having diode characteristics.

  In the circuit configuration shown in FIG. 7, the cathode (cathode) of the EL element 14 is connected to the cathode 32 formed in common with respect to the scanning lines A1 to An, and the reverse bias voltage shown in FIG. The application means 27 selectively applies a predetermined voltage level to the cathode. That is, here, when the voltage level applied to the common anode 31 is “Va”, for example, a voltage level of “Vh” or “Vl” is selectively applied to the cathode 32. The level difference of “Vl” with respect to “Va”, that is, Va−Vl is set to be in the forward direction (for example, about 10 V) in the EL element 14, and therefore “Vl” is selectively applied to the cathode 32. When set, the EL elements 14 constituting each pixel 30 are in a state capable of emitting light.

  Further, the level difference of “Vh” with respect to “Va”, that is, Va−Vh is set to be a reverse bias voltage (for example, about −8V) in the EL element 14. When “Vh” is applied, the EL elements 14 constituting each pixel 30 are brought into a non-light emitting state, and at this time, the diode 19 shown in FIG. 7 is brought into a conducting state by the reverse bias voltage.

  Since the circuit configuration described above can change the supply time (lighting time) of the drive current applied to the EL element which is a light emitting element, the substantial light emission luminance of the organic EL element 14 can be controlled. Therefore, the time gradation method is fundamental in the gradation expression in the driving device and driving method of the self-luminous display panel according to the present invention. As the time gray scale method, the weighting subframe method capable of supporting multiple gray scales with a smaller number of subframes than the simple subframe method is applied. The gradation expression in this circuit configuration is the gradation control means (first floor) constituted by the drive control circuit 21, the data driver 24, the write gate driver 25, and each pixel 30. (Tone control means, second gradation control means).

  Next, in the case of gradation display using this circuit configuration, a mode in which the erasing TFT 15 is not used will be described with reference to FIG. In the example shown in FIG. 8, as shown in FIG. 8A, the two pixel positions A and B are associated with positions in a grid pattern on the screen of the display panel 40, respectively. That is, the pixel positions of the same type are arranged so as not to be adjacent in the horizontal and vertical directions.

  Then, as shown in FIG. 8B, the frame periods in which the pixel positions A and B are driven to emit light are each divided into four sub-frames (SF1 to SF4). Further, as a weighted subframe method (first gradation control means), the frame period is divided into a set of one or a plurality of subframe periods. And gradation expression is made by lighting control of each weighted set. That is, in each frame shown in FIG. 8 (b), four subframes are divided into three groups (indicated by groups 1 to 3), and lighting control is performed for each group for each pixel, thereby expressing eight gradations. Made.

  More specifically, the smallest weighting coefficient is assigned to the set 3, and the larger weighting coefficients are assigned to the sets 2 and 1 in order. The group 1 and the group 2 excluding the group 3 are weighted in a period of 2: 1 as a time ratio of the element lighting time, and the four gradations can be expressed by the combination. However, for the group 3 expressing the lowest gradation level, the area gradation method (second gradation control means) controlled with the pixel positions A and B as one group is used, and the display period (SF4) of the group 3 is set. ), Only one of the pixel positions A and B is controlled to be lit for one subframe period. That is, in one frame, eight gradations are expressed by combining the lighting period of group 3 (weight 1) and the lighting periods of group 1 and group 2 (weight 4, weight 2).

  In the lighting period of the set 3, when one SF4 at the pixel positions A and B is turned on, the other is always turned off, and the pixel position at which the SF4 is turned on is controlled to be different between consecutive frames. The In other words, in each of the pixel positions A and B, control is performed so that the pixel positions at which SF4 is lit are alternated between successive frames.

  In the display of the image data, the organic EL element 14 is driven to emit light at the pixel positions A and B at the light emission drive timing of the corresponding frame configuration. That is, according to the above-described configuration, the light emission drive timing between consecutive frames in the same pixel and the light emission drive timing of the light emitting elements of pixels adjacent to each other in the horizontal and vertical directions are always different. Therefore, since the light emission pattern between consecutive frames in the same pixel or the light emission pattern between adjacent pixels is different, the occurrence of the moving image pseudo contour interference is suppressed, and the noise due to the moving image pseudo contour interference is dispersed.

  In addition, as described above, in the driving apparatus and driving method according to the present invention, gradation representation of image data is performed in units of pixels, so that a reduction in moving image resolution can be suppressed. Further, since the erasing TFT 15 is not particularly used, power consumption can be reduced.

  In the example shown in FIG. 8, the frame configuration corresponding to two types of pixel positions is shown. However, the frame configuration is not limited to this, and frame configurations corresponding to more types of pixel positions may be used. In this case, the erasing TFT 15 can be used effectively in order not to disturb the gradation expression. Next, an embodiment using a frame configuration corresponding to four types of pixel positions A, B, C, and D will be described with reference to FIG. As shown in FIG. 9A, in the four pixel positions A, B, C, and D, the same kind of pixel positions are not adjacent to each other in the horizontal and vertical directions and further in the oblique direction on the screen of the display panel 40. Are arranged as follows.

  As shown in FIG. 9B, the frame periods in which the pixel positions A, B, C, and D are driven to emit light are time-divided into five sub-frames (SF1 to SF5), respectively. Further, as a weighted subframe method (first gradation control means), the frame period is divided into a set of one or a plurality of subframe periods. And gradation expression is made by lighting control of each weighted set. In other words, in each frame shown in FIG. 9B, five sub-frames are divided into four groups (indicated by groups 1 to 4), and each group is controlled to turn on each group, thereby expressing 16 gradations. Made.

  More specifically, the minimum weighting coefficient is assigned to the set 4, and the larger weighting coefficients are assigned to the set 3, the set 2, and the set 1 in order. The groups 1 to 3 except for the group 4 are weighted to a period of 4: 2: 1 as a time ratio of the element lighting time, and eight gradations can be expressed by combinations of the groups 1 to 3 having different lighting periods. . However, the group 4 expressing the lowest gradation level is an area gradation method (second gradation control means) in which the pixel positions A, B, C, and D are controlled as one group. In the display period, control is performed so that only one of the pixel positions A, B, C, and D is lit for one subframe period. That is, in one frame, 16 gradations are expressed by combining the lighting period of group 4 and the lighting periods of group 1 to group 3.

  In the group 3, the EL element extinguishing period Er is provided in the subframe period, so that the lighting time in the subframe period is controlled to be ½ of one subframe period. That is, the lighting time control of the organic EL element 14 is performed in such a manner that the erasing TFT 15 is turned on in accordance with the control signal from the drive control circuit 21 while the EL element 14 emits light in each subframe period, and the capacitor is turned off in the extinction period Er. This is realized by discharging 13 charges. By using the erasing TFT 15 in this way, it is possible to easily realize multi-gradation even with a small number of subframes.

  Further, in the lighting period (SF5) of the set 4, when one pixel of the pixel positions A, B, C, and D is turned on, the other three pixels are always turned off, and a continuous frame period Each pixel is controlled to be turned off differently.

  In the display of the image data, the organic EL element 14 is driven to emit light at the pixel positions A, B, C, and D at the light emission drive timing of the corresponding frame configuration. According to the above-described configuration, the position of one pixel that is lit during the lighting period (SF5) of the group 4 is controlled so as to be always different between consecutive frames. That is, in the period of SF5 in one frame period, the light emission patterns at the four pixel positions are different between consecutive frames, so that the generation of noise due to the moving image pseudo contour interference is suppressed. In addition, in the period of SF5, only one pixel out of the four pixel positions emits light. In other words, pixels adjacent to each other do not emit light at the same time, so that noise due to moving image pseudo contour interference is dispersed. In addition, as described above, in the driving apparatus and driving method according to the present invention, gradation representation of image data is performed in units of pixels, so that a reduction in moving image resolution can be suppressed.

  As described above, in the embodiment according to the present invention, the frame period is time-divided into a plurality of subframe periods, and one or a plurality of subframe periods are weighted as a set, thereby lighting each pixel. A period is set, and in a minimum lighting period among the lighting periods, a plurality of adjacent pixels are regarded as one group, and one part of the pixels in each group is controlled to be turned off. In addition, a feature is that pixels that are controlled to be turned off for each group are controlled to be different for each frame period in each group. For this reason, since the light emission pattern between consecutive frames in the same pixel or the light emission pattern in pixels adjacent to each other is different, it is possible to suppress the occurrence of moving image pseudo contour interference and to disperse noise due to moving image pseudo contour interference. .

  Further, as described above, in the driving apparatus and driving method according to the present invention, the gradation representation of the image data is performed in units of pixels, so that it is possible to suppress a reduction in moving image resolution. Further, as in the example shown in FIG. 8, when the lighting control using the two pixel positions A and B is performed, it is not necessary to use the erasing TFT 15, so that power consumption can be reduced. Further, as in the example shown in FIG. 9, when the erasing TFT 15 is used, multi-gradation expression can be realized with a smaller number of subframes, and more in the group to which the area gradation method is applied. The pixel position can be a group unit.

  In the above-described embodiment, for the sake of convenience, the gradation expression is the case of 8 gradations and 16 gradations. However, the present invention is not limited to this, and the driving apparatus and driving according to the present invention are also applicable to multi-gradation display. The method can be applied. Further, the number of pixel positions classified by the difference in the frame configuration shown in the above embodiment, the arrangement relationship of the different types of pixel positions, and the like are examples, and the driving apparatus and driving of the present invention are not limited to these. The method can be applied. Further, even when the gradation expression is performed using the two pixel positions A and B, the erasing TFT 15 may be used. In this case, the multi-gradation expression can be performed with a smaller number of subframes.

It is a figure which shows an example of the circuit structure corresponding to one pixel in the conventional active matrix type display panel. It is a figure which shows typically the state which arranged the circuit structure which bears each pixel shown in FIG. 1 on the display panel. It is a figure for demonstrating the generation | occurrence | production mechanism of animation pseudo | simulation outline disturbance. In a time gradation method, it is a figure which shows the relationship between the sub-frame period in the case of changing a light emission pattern between continuous frames, and the lighting-on / off period of a light emitting element. It is a figure which shows the relationship between the sub-frame period at the time of combining an area gradation system and a time gradation system, and the lighting and light extinction period of a light emitting element. It is a block diagram which shows one Embodiment concerning the drive device and drive method of this invention. FIG. 7 is a diagram illustrating an example of a circuit configuration of one pixel among pixels arranged in a matrix on the display panel of FIG. 6. It is a figure which shows the relationship between the sub-frame period in the frame period corresponding to two pixel positions, respectively, and the lighting-on / off period of a light emitting element. It is a figure which shows the relationship between the sub-frame period in the frame period corresponding to four pixel positions, respectively, and the lighting and extinguishing period of a light emitting element.

Explanation of symbols

11 Control TFT
12 TFT for driving
13 Capacitor 14 Organic EL Element 15 Erasing TFT
DESCRIPTION OF SYMBOLS 19 Diode 21 Drive control circuit 22 A / D converter 23 Frame memory 24 Data driver 25 Write gate driver 26 Erase gate driver 27 Reverse bias voltage application means 30 Pixel 31 Anode 32 Cathode 40 Display panel A Scan line B Data line C Control line

Claims (9)

A drive device for an active matrix display panel comprising a plurality of light emitting elements arranged at intersections of a plurality of data lines and a plurality of scanning lines and controlled to emit light via at least lighting driving transistors, respectively.
First gradation control means for setting the lighting period of each pixel by time-dividing the frame period into a plurality of subframe periods and weighting one or more subframe periods as a set;
A second gradation that operates in a predetermined lighting period controlled by the first gradation control means, and controls a plurality of adjacent pixels as one group, and turns off a part of the pixels in each group. A drive device for a self-luminous display panel, comprising a control means.   The second gradation control means operates in a minimum lighting period controlled by the first gradation control means, and represents a gradation having a level smaller than the gradation level by the first gradation control means. The device for driving a self-luminous panel according to claim 1, wherein:   3. The pixel controlled to be turned off for each group by the second gradation control unit is controlled to be different for each frame period in each group. Drive device for self-luminous display panel. An erasing transistor for discharging and erasing charges from a capacitor holding the gate potential of the lighting driving transistor;
The first gradation display unit discharges the electric charge of the capacitor by the erasing transistor, turns off the light emitting element, and provides a light extinguishing period of the light emitting element. 4. The self-luminous display panel drive device according to any one of 3).   The light-emitting element is turned off in a sub-frame period by the erasing transistor, and the light-on period of the light-emitting element in the sub-frame period is weighted. Drive device for self-luminous display panel.   6. The self-luminous display panel driving device according to claim 1, wherein the light emitting element is an organic EL element. A driving method of an active matrix display panel provided with a plurality of light emitting elements arranged at intersections of a plurality of data lines and a plurality of scanning lines and controlled to emit light at least via lighting driving transistors, respectively.
The first gradation control means time-divides the frame period into a plurality of subframe periods, and sets one or a plurality of subframe periods as a set, thereby setting the lighting period of each pixel.
Among the lighting periods, the second gradation control means is operated during a predetermined lighting period, and a plurality of adjacent pixels are set as one group, and a part of the pixels in each group is controlled to be turned off. A self-luminous display panel driving method characterized by the above.   By operating the second gradation control means in the minimum lighting period controlled by the first gradation control means, a gradation having a level smaller than the gradation level by the first gradation control means. 8. The method for driving a self-luminous panel according to claim 7, wherein the expression is realized.   9. The pixel controlled to be turned off for each group by the second gradation control unit is controlled so as to be different for each frame period in each group. Driving method of self-luminous display panel.

Images