Liquid crystal display and driving method thereof

1. A liquid crystal display, comprising:

a signal controller, including

a luminance controller processing input image data with respective grays such that the luminance represented by a predetermined gray of the input image data is about 80 cd/m 2 , and

a gamma converter outputting output image data having a gamma characteristic adapted to a gamma 2.2 curve based on input image data, the gamma converter output being determined using a mathematical operation based on at least one difference curve and without using a look up table;

a data driver selecting and outputting gray voltages corresponding to the image data from the signal controller; and,

an inverter controlling a lamp such that the lamp emits light with luminance equal to or greater than 80 cd/m 2 , and

wherein the at least one difference curve has intersecting linear and quartic portions, and a critical value where the linear and quartic portions intersect.

2. The liquid crystal display of claim 1 , wherein the processing of the luminance controller includes addition of a predetermined data value to the input image data such that the luminance represented by the predetermined gray of the input image data be 80 cd/m 2 .

3. The liquid crystal display of claim 1 , wherein the gamma converter comprises an R data modifier, a G data modifier and a B data modifier for performing the gamma conversion for the input image data for respective red, green and blue colors, and each of the data modifiers maps the input image data into output image data having a gamma characteristic adapted to the gamma 2.2 curve.

4. The liquid crystal display of claim 3 , wherein the data modifiers include a non-volatile memory.

5. The liquid crystal display of claim 1 , wherein the gamma converter comprises an R data modifier, a G data modifier and a B data modifier for performing the gamma conversion for the input image data for respective red, green and blue colors, the liquid crystal display further comprises a target image data storage storing a map from the input image data into output image data having a gamma characteristic adapted to the gamma 2.2 curve and a controller loading the map stored in the target image data storage into the data modifiers, and the data modifiers select the output image data corresponding to the input image data from the loaded map and outputting the selected output image data.

6. The liquid crystal display of claim 5 , wherein the data modifiers comprise a volatile memory, and the target image data storage comprises a nonvolatile memory element.

7. The liquid crystal display of claim 5 , wherein the target image data storage includes a nonvolatile memory in the signal controller and a nonvolatile memory element provided external to the signal controller.

8. The liquid crystal display of claim 1 , wherein the gamma converter obtains the output image data from the input image data by way of a mathematical operation.

9. The liquid crystal display of claim 1 , wherein the at least one difference curve includes a red color difference curve and a blue color difference curve, the red color difference curve being symmetrical to the blue color difference curve.

10. The liquid crystal display of claim 9 , wherein the red color difference curve is a function of an 8-bit gray level value R having a critical value at a gray level of 160 and corresponding to a gray difference ΔR specified by

Δ

⁢

⁢

R

=

6

-

6

×

(

160

-

R

)

160

⁢

⁢

when  

⁢

R

<

160

,

and,

Δ

⁢

⁢

R

=

6

-

6

×

(

R

-

160

)

4

(

255

-

160

)

4

⁢

⁢

when  

⁢

R

≥

160.

11. The liquid crystal display of claim 9 , wherein the blue color difference curve is a function of an 8-bit gray level value B having a critical value at a gray level of 160 and corresponding to a gray difference ΔB specified by

Δ

⁢

⁢

B

=

⁢

-

6

+

6

×

(

160

-

B

)

160

⁢

⁢

when  

⁢

B

<

160

,

and,

Δ

⁢

⁢

B

=

⁢

-

6

+

6

×

(

B

-

160

)

4

(

255

-

160

)

4

⁢

⁢

when  

⁢

B

≥

160.

12. A method of driving a liquid crystal display, the method comprising:

controlling luminance of a backlight to be larger than about 80 cd/m 2 ;

controlling luminance of image data such that the luminance level represented by a predetermined gray of input image data is about 80 cd/m 2 ; and,

converting the gamma characteristic of the input image data to be adapted to a gamma 2.2 curve to provide a gamma converter output, the gamma convener output being determined using a mathematical operation based on at least one difference curve and without using a look up table, and

wherein the at least one difference curve has intersecting linear and quartic portions, and a critical value where the linear and quartic portions intersect.

13. The method of claim 12 , wherein the gamma characteristic conversion includes a mathematical operation realized on an application specific integrated circuit (ASIC).

14. The method of claim 12 , wherein the at least one difference curve includes a red color difference curve and a blue color difference curve, the red color difference curve being symmetrical to the blue color difference curve.

15. The method liquid crystal display of claim 14 , wherein the red color difference curve is a function of an 8-bit gray level value R having a critical value at a gray level of 160 and corresponding to a gray difference ΔR specified by

Δ

⁢

⁢

R

=

6

-

6

×

(

160

-

R

)

160

⁢

⁢

when  

⁢

R

<

160

,

and,

Δ

⁢

⁢

R

=

6

-

6

×

(

R

-

160

)

4

(

255

-

160

)

4

⁢

⁢

when  

⁢

R

≥

160.

16. The method of claim 14 , wherein the blue color difference curve is a function of an 8-bit gray level value B having a critical value at a gray level of 160 and corresponding to a gray difference ΔB specified by

Δ

⁢

⁢

B

=

⁢

-

6

+

6

×

(

160

-

B

)

160

⁢

⁢

when  

⁢

B

<

160

,

and,

Δ

⁢

⁢

B

=

⁢

-

6

+

6

×

(

B

-

160

)

4

(

255

-

160

)

4

⁢

⁢

when  

⁢

B

≥

160.