Drive Method Of Display Device, Drive Unit Of Display Device, Program Of The Drive Unit And Storage Medium Thereof, And Display Dvice Including The Drive Unit

• US 20080129762A1
• Filed: 03/08/2006
• Published: 06/05/2008
• Est. Priority Date: 03/15/2005
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Shiomi, Makoto
• Granted Patent: US 7,956,876 B2
• Time in Patent Office: Days
• US Class Current: 345/690
• CPC Class Codes: G09G 2320/0252 Improving the response speed
• CPC Class Codes: G09G 2320/0261 in the context of movement of objects on the screen or movement of the observer relative to the screen
• CPC Class Codes: G09G 2320/028 by changing the viewing angle properties, e.g. widening the viewing angle, adapting the viewing angle to the view direction
• CPC Class Codes: G09G 2320/0285 using tables for spatial correction of display data
• CPC Class Codes: G09G 2340/16 Determination of a pixel data signal depending on the signal applied in the previous frame
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence

Abstract

In one embodiment of the present invention, in the case of dark display on sub-pixels, a sub-frame processing section is disclosed which sets video data for a sub-frame to a value falling within the range for dark display, and increases or decreases video data for a sub-frame so as to control luminance of the sub-pixels. In the case of bright display, the sub-frame processing section sets video data to a value falling within the range for bright display, and increase or decreases video data so as to control luminance of the sub-pixels. A modulation processing section corrects video data of each frame and then outputs corrected video data to the sub-frame processing section. Also, the modulation processing section predicts luminance that the sub-pixels reach at the end of the frame and then stores prediction results for correction and prediction in the subsequent frame. This realizes a display device which is brighter, has a wider range of viewing angles, restrains deteriorated image quality caused by excessive emphasis of grayscale transition, and has improved moving image quality.

Claims

1. A drive method of a display device, comprising the step of (i) generating predetermined plural sets of output video data supplied to a pixel, in response to each input cycle of inputting input video data to the pixel, the plural sets of output video data being generated for driving the pixel by time division,

the drive method further comprising the step of:

(ii) prior to or subsequent to the step (i), correcting correction target data which is either the input video data or the plural output video data, and predicting luminance at which the pixel reaches at the end of a drive period of the correction target data, the drive period being a period in which the pixel is driven based on the corrected correction target data,

the step (i) including the sub steps of;

(I) in case where the input video data indicates luminance lower than a predetermined threshold, setting luminance of at least one of the plural sets of output video data to be at a value within a predetermined luminance range for dark display, and controlling a time integral value of the luminance of the pixel in periods in which the pixel is driven based on the plural sets of output video data, by increasing or decreasing at least one of the remaining sets of output video data; and

(II) in case where the input video data indicates luminance higher than the predetermined threshold, setting at least one of the plural sets of output video data to be at a value within a predetermined luminance range for bright display, and controlling a time integral value of the luminance of the pixel in periods in which the pixel is driven based on the plural sets of output video data, by increasing or decreasing at least one of the remaining sets of output video data,

the step (ii) including the sub steps of;

(III) correcting the correction target data based on a prediction result, among past prediction results, which indicates luminance that the pixel reaches at the beginning of a drive period of the correction target data; and

(IV) predicting luminance at the end of the drive period of the correction target data of the present time, at least based on the prediction result indicating the luminance at the beginning of the drive period and the correction target data of the present time, among the past prediction results, past supplied correction target data, and the correction target data of the present time.

2. A drive unit of a display device, comprising generation means for generating predetermined plural sets of output video data supplied to a pixel, in response to each of the input cycles of inputting input video data to the pixel, the plural sets of output video data being generated for driving the pixel by time division,

the drive unit further comprising:

correction means, provided prior to or subsequent to the generation means, for correcting correction target data which is either the input video data or the plural output video data, and predicting luminance at which the pixel reaches at the end of a drive period of the correction target data, the drive period being a period in which the pixel is driven based on the corrected correction target data,

the generation means performing control so as to;

(i) in case where the input video data indicates luminance lower than a predetermined threshold, set luminance of at least one of the plural sets of output video data at a value within a predetermined luminance range for dark display, and control a time integral value of the luminance of the pixel in periods in which the pixel is driven based on the plural sets of output video data, by increasing or decreasing at least one of the remaining sets of output video data; and

(ii) in case where the input video data indicates luminance higher than the predetermined threshold, set luminance of at least one of the plural sets of output video data at a value within a predetermined luminance range for bright display, and control a time integral value of the luminance of the pixel in periods in which the pixel is driven based on the plural sets of output video data, by increasing or decreasing at least one of the remaining sets of output video data, and

the correction means correcting the correction target data based on a prediction result, among past prediction results, which indicates luminance that the pixel reaches at the beginning of a drive period of the correction target data, and predicting luminance at the end of the drive period of the correction target data of the present time, at least based on the prediction result indicating the luminance at the beginning of the drive period and the correction target data of the present time, among the past prediction results, past supplied correction target data, and the correction target data of the present time.

3. The drive unit according to claim 2, wherein

the correction target data is input video data, and

the correction means is provided prior to the generation means and predicts, as luminance that the pixel reaches at the end of a drive period of the correction target data, luminance that the pixel reaches at the end of periods in which the pixel is driven based on the plural sets of output video data, which have been generated based on corrected input video data by the generation means.

4. The drive unit according to claim 2, wherein

the correction means is provided subsequent to the generation means and corrects the sets of output video data as the correction target data.

5. The drive unit according to claim 4, wherein

the correction means includes:

a correction section which corrects the plural sets of output video data generated in response to each of the input cycles and outputs sets of corrected output video data corresponding to respective divided periods into which the input cycle is divided, the number of the divided periods corresponding to the number of the plural sets of output video data; and

a prediction result storage section which stores a prediction result regarding a last divided period among the prediction results, wherein

in a case where the correction target data corresponds to a first divided period, the correction section corrects the correction target data based on a prediction result read out from the prediction result storage section,

in a case where the correction target data corresponds to a second or subsequent divided period, the correction section predicts the luminance at the beginning of the drive period, based on (a) output video data corresponding to a divided period which is prior to the divided period corresponding to the correction target data and (b) the prediction result stored in the prediction result storage section, and corrects the correction target data according to the prediction result,

the correction section predicts the luminance of the pixel at the end of a drive period of the output video data corresponding to the last divided period, based on (A) the output video data corresponding to the last divided period, (B) the output video data corresponding to a divided period which is prior to the divided period corresponding to the output video data (A), and (C) the prediction result stored in the prediction result storage section, and stores the thus obtained prediction result in the prediction result storage section.

6. The drive unit according to claim 5, wherein

the pixel is one of a plurality of pixels,

in accordance with input video, data for each of the pixels, the generation means generates predetermined plural of sets of output video data supplied to each of the pixels, in response to each of the input cycles, the correction means corrects the sets of output video data to be supplied to each of the pixels and stores prediction results corresponding to the respective pixels in the prediction result storage section,

the generation means generates, for each of the pixels, the predetermined number of sets of output video data to be supplied to the each of the pixels in each of the input cycles, and

the correction section reads out, for each of the pixels, prediction results regarding the pixel predetermined number of times in each of the input cycles, and based on these prediction results and the sets of output video data, for each of the pixels, at least one process of writing of the prediction result is thinned out from processes of prediction of luminance at the end of the drive period and processes of storing the prediction result, which can be performed plural number of times in each of the input cycles.

7. The drive unit according to claim 2, wherein

the generation means controls the time integral value of the luminance of the pixel in periods in which the pixel is driven based on the plural sets of output video data by increasing or decreasing particular output video data which is a particular one of the remaining sets of output video data, and sets the remaining sets of output video data other than the particular output video data at either a value indicating luminance falling within the predetermined range for dark display or a value indicating luminance falling within the range for bright display.

8. The drive unit as defined in claim 7, wherein

provided that the periods in which the pixel is driven by said plural sets of output video data are divided periods whereas a period constituted by the divided periods and in which the pixel is driven by said plural sets of output video data is a unit period, the generation means selects, as the particular output video data, a set of output video data corresponding to a divided period which is closest to a temporal central position of the unit period, among the divided periods, in a region where luminance indicated by the input video data is lowest, and when luminance indicated by the input video data gradually increases and hence the particular output video data enters the predetermined range for bright display, the generation means sets the set of video data in that divided period at a value falling within the range for bright display, and selects, as new particular output video data, a set of output video data in a divided period which is closest to the temporal central position of the unit period, among the remaining divided periods.

9. The drive unit as defined in claim 7, wherein

a ratio between the periods in which the pixel is driven based on said plural sets of output video data is set so that a timing to determine which set of output video data is selected as the particular output video data is closer to a timing at which a range of brightness that the pixel can reproduce is equally divided than a timing at which luminance that the pixel can reproduce is equally divided.

10. A program which causes a computer to operate as the foregoing means according to claim 2.

11. A storage medium storing the program according to claim 10.

12. A display device, comprising:

the drive unit according to claim 2; and

a display section including pixels driven by the drive unit.

13. The display device according to claim 12, further comprising image receiving means which receives television broadcast and supplies, to the drive unit of the display device, a video signal indicating an image transmitted by the television broadcast, the display section being a liquid crystal display panel, wherein

the display device functions as a liquid crystal television receiver.

14. The display device according to claim 12, wherein

the display section is a liquid crystal display panel, the drive unit of the display device receives a video signal from outside, and

the display device functions as a liquid crystal monitor device which displays an image indicated by the video signal.