Liquid crystal display and method fo driving thereof

Abstract

A liquid crystal display includes a signal controller having a luminance controller receiving image data from an external graphic source and controlling the luminance of the image data such that the luminance at the gray expressed by a specific data value of the image data is established to be 80 cd/m 2 , and a gamma converter outputting image data each having a gamma characteristic adapted to a gamma 2.2 curve. The gamma converter output is determined without using a look up table based on at least one difference curve having a linear portion, a quartic portion, and a critical value where the linear portion and the quartic portion intersect. The liquid crystal display further includes a data driver receiving the image data for selecting and outputting gray voltages corresponding to the image data, and an inverter controlling a lamp to emit light with a luminance of 80 cd/m 2 or more.

1 . A 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 be about 80 cd/m2, and a gamma converter outputting output image data have gamma characteristic adapted to a gamma 2.2 curve based on input image data;   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 larger than 80 cd/m2.   
   
   
       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/m2. 
   
   
       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 nonvolatile 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 using a look up table. 
   
   
       9 . A method of driving a display, the method comprising:
 controlling luminance of a backlight to be larger than about 80 cd/m2;   controlling luminance of image data with respective grays such that the luminance level represented by a predetermined gray of input image data be about 80 cd/m2; and   converting gamma characteristic of the input image data to be adapted to a gamma 2.2 curve.   
   
   
       10 . The method of  claim 9 , wherein the gamma characteristic conversion includes a mapping operation using a map stored in a nonvolatile memory.