Image signal compensation apparatus and liquid crystal display including the same

Abstract

Provided are an image signal compensation apparatus and a liquid crystal display (LCD) including the same. The image signal compensation apparatus includes a lookup table (LUT) and an image signal compensation unit. The LUT includes reference data that corresponds to each combination of first and second reference gray levels and is arranged in a matrix. The image signal compensation unit receives first and second image signals, receives reference data corresponding to the first and second image signals from the LUT, and compensates the second image signal using the reference data. The reference data includes diagonal reference data located on a diagonal line in the matrix, and at least one diagonal reference data from among the diagonal reference data has a different value from a corresponding combination of the first and second reference gray levels.

1 . An image signal compensation apparatus, comprising:
 a lookup table (LUT) comprising reference data that corresponds to each combination of first reference gray levels and second reference gray levels and is arranged in a matrix; and   an image signal compensation unit to receive a first image signal and a second image signal, to receive reference data corresponding to the first image signal and the second image signal from the LUT, and to compensate the second image signal using the reference data,   wherein the reference data comprises diagonal reference data located on a diagonal line in the matrix, and at least one diagonal reference data from among the diagonal reference data has a different value from a corresponding combination of a first reference gray level and a second reference gray level.   
   
   
       2 . The apparatus of  claim 1 , wherein the first reference gray levels and the second reference gray levels correspond to upper bits of the first image signal and the second image signal, respectively. 
   
   
       3 . The apparatus of  claim 1 , wherein each diagonal reference data corresponding to a combination of the first reference gray level and the second reference gray level has a value corresponding to a combination of the gray level of “a” and a gray level of “b”, where a≠b when each of the first and second reference gray levels is a gray level of “a”. 
   
   
       4 . The apparatus of  claim 3 , wherein a third reference gray level adjacent to the first reference gray level is a gray level of “c”, and a difference between the gray level of “b” and the gray level of “a” is less than a difference between the gray level of “c” and the gray level of “a”. 
   
   
       5 . The apparatus of  claim 4 , wherein a fourth reference gray level adjacent to the second reference gray level is a gray level of “d”, and the difference between the gray level of “b” and the gray level of “a” is less than a difference between the gray level of “d” and the gray level of “a”. 
   
   
       6 . The apparatus of  claim 3 , wherein the matrix is divided into a rising region and a falling region by the diagonal reference data, and each diagonal reference data has a value that belongs to the rising region and a value that belongs to the falling region. 
   
   
       7 . The apparatus of  claim 5 , wherein the difference between the gray level of “a” and the gray level of “c” or the difference between the gray level of “a” and the gray level of “d” is one. 
   
   
       8 . The apparatus of  claim 4 , wherein a value corresponding to a combination of the gray level of “a” and the gray level of “b” is a measured value for the first image signal and the second image signal. 
   
   
       9 . The apparatus of  claim 1 , wherein the reference data further comprises additional reference data having a value that is located on a second diagonal line or a third diagonal line when the matrix is divided into the rising region and the falling region by the diagonal reference data, a first diagonal line is defined as a diagonal line connecting the diagonal reference data, the second diagonal line is defined as the first diagonal line shifted toward the rising region, and the third diagonal line is defined as the first diagonal line shifted toward the falling region. 
   
   
       10 . The apparatus of  claim 9 , wherein the image signal compensation unit compensates the second image signal through quadratic interpolation using the additional reference data and two or more pieces of diagonal reference data that are adjacent to the additional reference data. 
   
   
       11 . The apparatus of  claim 1 , wherein the reference data is a dynamic capacitance compensation (DCC) value corresponding to each combination of the first reference gray levels and the second reference gray levels. 
   
   
       12 . The apparatus of  claim 1 , wherein the image signal compensation unit compensates the second image signal using bi-linear interpolation or triangular bi-linear interpolation. 
   
   
       13 . A liquid crystal display (LCD), comprising:
 a liquid crystal panel to display an image;   a timing controller to receive a first image signal and a second image signal that are sequentially provided and to output a compensated image signal obtained by compensating the second image signal; and   a data driver to receive the compensated image signal and to apply a data voltage corresponding to the compensated image signal to the liquid crystal panel,   wherein the timing controller comprises:   a LUT comprising reference data that corresponds to each combination of first reference gray levels and second reference gray levels and is arranged in a matrix; and   an image signal compensation unit to receive the first image signal and the second image signal, to receive reference data corresponding to the first image signal and the second image signal from the LUT, and to compensate the second image signal using the reference data,   wherein the reference data comprises diagonal reference data located on a diagonal line in the matrix, and at least one diagonal reference data from among the diagonal reference data has a different value from a corresponding combination of a first reference gray level and a second reference gray level.   
   
   
       14 . The LCD of  claim 13 , wherein the first reference gray levels and the second reference gray levels correspond to upper bits of the first image signal and the second image signal, respectively. 
   
   
       15 . The LCD of  claim 13 , wherein each diagonal reference data corresponding to a combination of the first reference gray level and the second reference gray level has a value corresponding to a combination of the gray level of “a” and a gray level of “b”, where a≠b when each of the first reference gray level and the second reference gray level is a gray level of “a”. 
   
   
       16 . The LCD of  claim 15 , wherein a third reference gray level adjacent to the first reference gray level is a gray level of “c”, a difference between the gray level of “b” and the gray level of “a” is less than a difference between the gray level of “c”, and the gray level of “a”, and a fourth reference gray level adjacent to the second reference gray level is a gray level of “d”, and the difference between the gray level of “b” and the gray level of “a” is less than a difference between the gray level of “d” and the gray level of “a”. 
   
   
       17 . The LCD of  claim 16 , wherein the difference between the gray level of “a” and the gray level of “c” or the difference between the gray level of “a” and the gray level of “d” is one. 
   
   
       18 . The LCD of  claim 15 , wherein the reference data further comprises additional reference data having a value which is located on a second diagonal line or a third diagonal line when the matrix is divided into a rising region and a falling region by the diagonal reference data, a first diagonal line is defined as a diagonal line connecting the diagonal reference data, the second diagonal line is defined as the first diagonal line shifted toward the rising region, and the third diagonal line is defined as the first diagonal line shifted toward the falling region. 
   
   
       19 . The LCD of  claim 18 , wherein the image signal compensation unit compensates the second image signal through quadratic interpolation using first additional reference data or second additional reference data and two or more pieces of diagonal reference data that are adjacent to the first additional reference data or the second additional reference data. 
   
   
       20 . The LCD of  claim 13 , wherein the reference data is a DCC value corresponding to each combination of the first reference gray levels and the second reference gray levels. 
   
   
       21 . The LCD of  claim 13 , wherein the image signal compensation unit compensates the second image signal using bi-linear interpolation or triangular bi-linear interpolation.