Gamma correction device for a display device, gamma correction method for a display device, and display device

1. A display device comprising:

a display panel including a plurality of pixels;

a reference gray mapping table configured to store reference gray mapping information indicating gamma correction reference gray levels to which reference gray levels are mapped;

a gray mapper configured to map original gray levels indicated by input data to gamma correction gray levels using the reference gray mapping information stored in the reference gray mapping table;

a dither configured to generate dithered output data to represent the gamma correction gray levels using the original gray levels, wherein a number of bits representing each of the gamma correction gray levels is greater than a number of bits representing each of the original gray levels; and

a data driver configured to drive the display panel using the dithered output data.

2. The display device of claim 1 , wherein the gamma correction reference gray levels are determined using luminances of the display device measured at the reference gray levels and a target gamma value.

3. The display device of claim 1 , wherein luminances of the display device are measured at the reference gray levels that are selected among the original gray levels,

wherein upscaled gray luminances of the display device respectively corresponding to upscaled gray levels, each of which is represented by a number of bits greater than the number of bits representing each of the original gray levels, are determined using the luminances measured at the reference gray levels,

wherein target luminances of the reference gray levels are determined using one of the luminances measured at the reference gray levels and a target gamma value, and

wherein the gamma correction reference gray levels to which the reference gray levels are mapped are determined by searching the upscaled gray luminances closest to the target luminances of the reference gray levels.

4. The display device of claim 3 , wherein the upscaled gray luminances, at the upscaled gray levels that are the same as the reference gray levels, are determined as the luminances measured at the reference gray levels, and

wherein the upscaled gray luminances, at the upscaled gray levels between the reference gray levels, are determined by interpolating the luminances measured at the reference gray levels.

5. The display device of claim 3 , wherein the number of bits representing each of the upscaled gray levels is determined as a sum of the number of bits representing each of the original gray levels and a number of bits of dithering performed by the dither.

6. The display device of claim 3 , wherein the target luminances of the reference gray levels are determined using a luminance measured at a maximum reference gray level among the reference gray levels.

7. The display device of claim 6 , wherein the target luminances of the reference gray levels are determined using an equation, “Ytgt=Ymax*(Gtgt/Gmax){circumflex over ( )}TGV”, and

wherein Ytgt represents one of the target luminances of the reference gray level, Ymax represents the luminance measured at the maximum reference gray level, Gtgt represents a target reference gray level, Gmax represents the maximum reference gray level, and TGV represents the target gamma value.

8. The display device of claim 3 , wherein a lookup table storing the upscaled gray luminances respectively corresponding to the upscaled gray levels is generated using the luminances measured at the reference gray levels, and

wherein the upscaled gray levels corresponding to the upscaled gray luminances closest to the target luminances in the lookup table are determined as the gamma correction reference gray levels to which the reference gray levels are mapped.

9. The display device of claim 1 , further comprising:

a gamma table configured to store gamma correction data indicating gamma reference voltages at the reference gray levels that are selected among the original gray levels; and

a gamma voltage generator configured to generate data voltages respectively corresponding to the original gray levels using the gamma correction data stored in the gamma table.

10. The display device of claim 9 , wherein the data driver receives the data voltages respectively corresponding to the original gray levels from the gamma voltage generator, receives the dithered output data from the dither, and provides the plurality of pixels with the data voltages indicated by the dithered output data.

11. The display device of claim 1 , wherein the reference gray mapping table stores, as the reference gray mapping information, a shift sign bit and shift amount bits with respect to each of the reference gray levels.

12. The display device of claim 1 , wherein the gray mapper maps the reference gray levels among the original gray levels to the gamma correction reference gray levels using the reference gray mapping information, and determines the gamma correction gray levels, to which the original gray levels between the reference gray levels are mapped, by interpolating the gamma correction reference gray levels.

13. The display device of claim 12 , wherein, if a result value of the interpolation for the gamma correction reference gray levels is not representable by the dither, the gray mapper determines a gray level closest to the result value of the interpolation, among gray levels representable by the dither, as a corresponding gamma correction gray level.

14. The display device of claim 1 , wherein the gray mapper includes:

a primary mapping calculator configured to map the reference gray levels to the gamma correction reference gray levels using the reference gray mapping information, and to interpolate the gamma correction reference gray levels to determine the gamma correction gray levels to which the original gray levels between the reference gray levels are mapped; and

a secondary mapping calculator configured to determine gray levels closest to result values of the interpolation among gray levels representable by the dither as the gamma correction gray levels to which the original gray levels between the reference gray levels are mapped.

15. The display device of claim 1 , further comprising:

a gamma flattener configured to perform a gamma flattening operation on the input data.

16. A gamma correction device for a display device, the gamma correction device comprising:

a luminance measurer configured to measure luminances of the display device at reference gray levels selected among original gray levels;

a gamma reference voltage determiner configured to determine gamma reference voltages at the reference gray levels using the measured luminances;

a lookup table generator configured to generate a lookup table storing upscaled gray luminances of the display device respectively corresponding to upscaled gray levels using the luminances measured at the reference gray levels, wherein a number of bits representing each of the upscaled gray levels is greater than a number of bits representing each of the original gray levels;

a target luminance determiner configured to determine target luminances of the reference gray levels using one of the luminances measured at the reference gray levels and a target gamma value; and

a gamma correction reference gray determiner configured to determine gamma correction reference gray levels to which the reference gray levels are mapped by searching the upscaled gray luminances closest to the target luminances of the reference gray levels in the lookup table.

17. The gamma correction device of claim 16 , wherein the lookup table generator determines the upscaled gray luminances, at the upscaled gray levels that are the same as the reference gray levels, as the luminances measured at the reference gray levels, and determines the upscaled gray luminances, at the upscaled gray levels between the reference gray levels, by interpolating the luminances measured at the reference gray levels.

18. The gamma correction device of claim 16 , wherein the number of bits representing each of the upscaled gray levels is determined as a sum of the number of bits representing each of the original gray levels and a number of bits of dithering performed in the display device.

19. The gamma correction device of claim 16 , wherein the gamma correction device writes gamma correction data, indicating the gamma reference voltages at the reference gray levels, to the display device such that the display device generates data voltages using the gamma reference voltages, and writes reference gray mapping information indicating the gamma correction reference gray levels, to which the reference gray levels are mapped to the display device, such that the display device maps the original gray levels indicated by input data of the display device to gamma correction gray levels using the gamma correction reference gray levels.

20. A gamma correction method for a display device, the gamma correction method comprising:

measuring luminances of the display device at reference gray levels selected among original gray levels;

determining gamma reference voltages at the reference gray levels using the measured luminances;

generating a lookup table storing upscaled gray luminances of the display device respectively corresponding to upscaled gray levels using the luminances measured at the reference gray levels, wherein a number of bits representing each of the upscaled gray levels is greater than a number of bits representing each of the original gray levels;

determining target luminances of the reference gray levels using one of the luminances measured at the reference gray levels and a target gamma value; and

determining gamma correction reference gray levels to which the reference gray levels are mapped by searching the upscaled gray luminances closest to the target luminances of the reference gray levels in the lookup table.