Display device and driving method thereof

1. A display device, comprising:

a display panel including a plurality of pixels;

a data driver which transmits data voltages to the plurality of pixels; and

a signal controller which receives an input image signal and an input control signal, and controls the data driver,

wherein the signal controller calculates a ratio of a first type of pattern in an image based on the input image signal, identifies whether a previous inversion mode is a reference inversion mode or a modified inversion mode, uses the ratio of the first type of pattern when the previous inversion mode is the reference inversion mode or when the previous inversion mode is the modified inversion mode, generates a polarity signal based on the ratio of the first type of pattern, and transmits the polarity signal to the data driver.

2. The display device of claim 1 , wherein the signal controller comprises:

an inversion mode identifying unit which identifies whether the previous inversion mode is the reference inversion mode or the modified inversion mode,

a pattern ratio detecting unit which detects a ratio of the first type of pattern for the reference inversion mode based on the input image signal, and

an inversion mode determining unit which determines an inversion mode of a current frame based on the ratio of the first type of pattern.

3. The display device of claim 2 , wherein

the inversion mode determining unit uses the ratio of the first type of pattern when the previous inversion mode is the reference inversion mode or when the previous inversion mode is the modified inversion mode.

4. The display device of claim 3 , wherein

the inversion mode determining unit determines the inversion mode of the current frame as the modified inversion mode, when the ratio of the first type of pattern is less than a first reference value,

the inversion mode determining unit determines the inversion mode of the current frame as the reference inversion mode, when the ratio of the first type of pattern is greater than or equal to the first reference value and the previous inversion mode is the reference inversion mode,

the inversion mode determining unit determines the inversion mode of the current frame as the reference inversion mode, when the ratio of the first type of pattern is greater than a second reference value, and

the inversion mode determining unit determines the inversion mode of the current frame as the modified inversion mode, when the ratio of the first type of pattern is less than or equal to the second reference value and the previous inversion mode is the modified inversion mode.

5. The display device of claim 4 , wherein

the first reference value is less than the second reference value.

6. The display device of claim 3 , wherein

the pattern ratio detecting unit detects a ratio of a second type of pattern in the image for the reference inversion mode based on the input image signal,

the inversion mode determining unit determines the inversion mode of the current frame as the modified inversion mode, when the ratio of the second type of pattern is greater than a third reference value,

the inversion mode determining unit determines the inversion mode of the current frame as the reference inversion mode, when the ratio of the second type of pattern is less than or equal to the third reference value and the previous inversion mode is the reference inversion mode,

the inversion mode determining unit determines the inversion mode of the current frame as the reference inversion mode, when the ratio of the first type of pattern is greater than a second reference value, and

the inversion mode determining unit determines the inversion mode of the current frame as the modified inversion mode, when the ratio of the first type of pattern is less than or equal to the second reference value and the previous inversion mode is the modified inversion mode.

7. The display device of claim 3 , wherein

the pattern ratio detecting unit detects a ratio of a second type of pattern in the image for the reference inversion mode based on the input image signal,

the inversion mode determining unit determines the inversion mode of the current frame as the modified inversion mode, when the ratio of the first type of pattern is less than a first reference value,

the inversion mode determining unit determines the inversion mode of the current frame as the reference inversion mode, when the ratio of the first type of pattern is greater than or equal to the first reference value and the previous inversion mode is the reference inversion mode,

the inversion mode determining unit determines the inversion mode of the current frame as the reference inversion mode, when the ratio of the second type of pattern is less than a fourth reference value, and

the inversion mode determining unit determines the inversion mode of the current frame as the modified inversion mode, when the ratio of the second type of pattern is greater than or equal to the fourth reference value and the previous inversion mode is the modified inversion mode.

8. The display device of claim 3 , wherein

the ratio of the first type of pattern is represented by one of percentage, the number of pixels and the number of pixel blocks, each of which includes at least one of at least two pixels, at least one pixel row and at least one pixel column.

9. The display device of claim 1 , wherein

the ratio of the first type of pattern is calculated by determining whether a unit image of the image based on the input image signal corresponds to a second type of pattern, and

the unit image is an image displayed by any one of a pixel and a pixel block, wherein the pixel block include one of at least two pixels, at least one pixel row, at least one pixel column and a combination thereof.

10. A driving method of a display device, the method comprising:

calculating a ratio of a first type of pattern in an image based on an input image signal;

identifying whether a previous inversion mode is a reference inversion mode or a modified inversion mode;

using the ratio of the first type of pattern when the previous inversion mode is the reference inversion mode or when the previous inversion mode is the modified inversion mode; and

determining an inversion mode of a current frame based on the ratio of the first type of pattern,

wherein the display device comprises:

a display panel including a plurality of pixels;

a data driver; and

a signal controller which receives the input image signal and an input control signal to control the data driver.

11. The method of a display device of claim 10 , further comprising:

identifying whether a previous inversion mode is a reference inversion mode or a modified inversion mode.

12. The driving method of a display device of claim 11 , wherein

the ratio of the first type of pattern is a ratio of the first type of pattern in the image displayed in the reference inversion mode.

13. The driving method of a display device of claim 12 , wherein the calculating the ratio of the first type of pattern in the image comprises:

determining whether a unit image of the image based on the input image signal corresponds to a second type of pattern, and

the unit image is an image display by one of a pixel and a pixel block, wherein the pixel block comprises at least two pixels, at least one pixel row, at least one pixel column or a combination thereof.

14. The driving method of a display device of claim 12 , wherein the determining the inversion mode of the current frame comprises:

determining the inversion mode of the current frame as the modified inversion mode, when the ratio of the first type of pattern is less than a first reference value;

determining the inversion mode of the current frame as the reference inversion mode, when the ratio of the first type of pattern is greater than or equal to the first reference value and the previous inversion mode is the reference inversion mode;

determining the inversion mode of the current frame as the reference inversion mode, when the ratio of the first type of pattern is greater than a second reference value; and

determining the inversion mode of the current frame as the modified inversion mode, when the ratio of the first type of pattern is less than or equal to the second reference value and the previous inversion mode is the modified inversion mode.

15. The driving method of a display device of claim 14 , wherein

the first reference value is less than the second reference value.

16. The driving method of a display device of claim 12 , wherein

the calculating the ratio of the first type of pattern further comprises detecting a ratio of a second type of pattern in the image for the reference inversion mode based on the input image signal.

17. The driving method of a display device of claim 16 , wherein the determining the inversion mode of the current frame comprises:

determining the inversion mode of the current frame as the modified inversion mode, when the ratio of the second type of pattern is greater than a third reference value;

determining the inversion mode of the current frame as the reference inversion mode, when the ratio of the second type of pattern is less than or equal to the third reference value and the previous inversion mode is the reference inversion mode;

determining the inversion mode of the current frame as the reference inversion mode, when the ratio of the first type of pattern is greater than a second reference value; and

determining the inversion mode of the current frame as the modified inversion mode, when the ratio of the first type of pattern is less than or equal to the second reference value and the previous inversion mode is the modified inversion mode.

18. The driving method of a display device of claim 16 , wherein the determining the inversion mode of the current frame comprises:

determining the inversion mode of the current frame as the modified inversion mode, when the ratio of the first type of pattern is less than a first reference value;

determining the inversion mode of the current frame as the reference inversion mode, when the ratio of the first type of pattern is greater than or equal to the first reference value and the previous inversion mode is the reference inversion mode;

determining the inversion mode of the current frame as the reference inversion mode, when the ratio of the second type of pattern is less than a fourth reference value; and

determining the inversion mode of the current frame as the modified inversion mode, when the ratio of the second type of pattern is greater than or equal to the fourth reference value and the previous inversion mode is the modified inversion mode.

19. The driving method of a display device of claim 10 , wherein

the ratio of the first type of pattern is represented in a unit, which is one of percentage, a number of pixels and a number of pixel blocks, wherein each of the pixel blocks comprises at least two pixels, at least one pixel row or at least one pixel column.