Method of driving a display panel and organic light emitting display device employing the same

1. A method of driving a display panel, the method comprising:

grouping m adjacent pixels, which output a same color light, into one pixel-group in the display panel, where m is an integer greater than or equal to two;

determining whether a unit grayscale to be implemented by the pixel-group is greater than or equal to a reference grayscale by analyzing respective data signals applied to the pixel-group;

performing, in response to the unit grayscale being greater than or equal to the reference grayscale, a normal driving that implements the unit grayscale by controlling all of the m adjacent pixels to emit light with first luminance corresponding to the respective data signals; and

performing, in response to the unit grayscale being less than the-reference grayscale, a combination driving that implements the unit grayscale by controlling only a portion of the m adjacent pixels to emit light with second luminance that is greater than the first luminance.

2. The method of claim 1 , wherein, in response to the combination driving being performed, n adjacent pixels, where n is an integer greater than or equal to 1 and smaller than m, are selected among the m adjacent pixels, and the second luminance is m/n times the first luminance.

3. The method of claim 2 , wherein, in response to the combination driving being performed, the n adjacent pixels are differently and alternately selected among the m adjacent pixels for respective frames.

4. The method of claim 3 , wherein the combination driving is separately performed on blue color pixels, red color pixels, and green color pixels.

5. The method of claim 3 , wherein the combination driving is separately performed on blue color pixels, red color pixels, green color pixels, and white color pixels.

6. The method of claim 1 , wherein, in response to a driving frequency of the display panel being less than a determined reference frequency, the normal driving is performed on all pixel-groups of the display panel.

7. The method of claim 1 , wherein, in response to a number of low-grayscale pixel-groups of which the unit grayscale is less than the reference grayscale being greater than or equal to a reference number in the display panel, the combination driving is performed on all pixel-groups of the display panel.

8. The method of claim 1 , wherein, in response to a number of high-grayscale pixel-groups of which the unit grayscale is greater than or equal to the reference grayscale being greater than or equal to a reference number in the display panel, the normal driving is performed on all pixel-groups of the display panel.

9. A method of driving a display panel, the method comprising:

grouping m adjacent pixels, which output a same color light, into one pixel-group in the display panel, where m is an integer greater than or equal to two;

determining whether a unit grayscale to be implemented by the pixel-group is greater than or equal to a reference grayscale by analyzing respective data signals applied to the pixel-group;

performing, in response to the unit grayscale belonging to a high-grayscale region that is greater than or equal to the reference grayscale, a normal driving that implements the unit grayscale by controlling all of the m adjacent pixels to emit light with first luminance corresponding to the respective data signals; and

performing, in response to the unit grayscale belonging to first through (k)-th low-grayscale regions that are less than the reference grayscale, where k is an integer greater than or equal to two, a combination driving that implements the unit grayscale by controlling n adjacent pixels of the m adjacent pixels, where n is an integer greater than or equal to 1 and less than m, to emit light with second luminance that is m/n times the first luminance,

wherein n and m are differently determined for the first through (k)-th low-grayscale regions.

10. The method of claim 9 , wherein, in response to the combination driving being performed, the n adjacent pixels are differently and alternately selected among the m adjacent pixels for respective frames.

11. The method of claim 10 , wherein the combination driving is separately performed on blue color pixels, red color pixels, and green color pixels.

12. The method of claim 10 , wherein the combination driving is separately performed on blue color pixels, red color pixels, green color pixels, and white color pixels.

13. The method of claim 9 , wherein, in response to a driving frequency of the display panel being less than a reference frequency, the normal driving is performed on all pixel-groups of the display panel.

14. The method of claim 9 , wherein, in response to a number of low-grayscale pixel-groups of which the unit grayscale is less than the reference grayscale being greater than or equal to a reference number in the display panel, the combination driving is performed on all pixel-groups of the display panel.

15. The method of claim 9 , wherein, in response to a number of high-grayscale pixel-groups of which the unit grayscale is greater than or equal to the reference grayscale being greater than or equal to a reference number in the display panel, the normal driving is performed on all pixel-groups of the display panel.

16. An organic light emitting display device, comprising:

a display panel comprising pixels, each pixel comprising an organic light emitting element;

a display panel driving circuit configured to drive the display panel; and

a driving control circuit configured to:

group m adjacent pixels, which output a same color light, into one pixel-group in the display panel, where m is an integer greater than or equal to two;

determine whether a unit grayscale to be implemented by the pixel group is greater than or equal to a reference grayscale based on analyzation of respective data signals applied to the pixel-group;

selectively perform, based on whether the unit grayscale to be implemented by the pixel-group is greater than or equal to the reference grayscale, a normal driving configured to operate all of the m adjacent pixels to emit light with a first luminance corresponding to the respective data signals or a combination driving configured to operate only a portion of the m adjacent pixels to emit light with a second luminance that is greater than the first luminance.

17. The organic light emitting display device of claim 16 , wherein the driving control circuit is part of the display panel driving circuit.

18. The organic light emitting display device of claim 16 , wherein, in response to the combination driving being performed, the driving control circuit is configured to differently and alternately select the portion of the m adjacent pixels for respective frames to alternate a light emitting pattern of the pixel-group for the frames.

19. The organic light emitting display device of claim 18 , wherein:

the driving control circuit is configured to:

perform, in response to the unit grayscale belonging to a high-grayscale region that is greater than or equal to the reference grayscale, the normal driving that implements the unit grayscale by controlling all of the m adjacent pixels to emit light with the first luminance corresponding to respective data signals; and

perform, in response to the unit grayscale belonging to first through (k)-th low-grayscale regions that are less than the reference grayscale, where k is an integer greater than or equal to two, the combination driving that implements the unit grayscale by controlling n adjacent pixels of the m adjacent pixels, where n is an integer greater than or equal to one and less than m, to emit light with the second luminance that is m/n times the first luminance; and

n and m are differently determined for the first through (k)-th low-grayscale regions.