Color Liquid Crystal Display Device And Gamma Correction Method For The Same

Abstract

A color liquid crystal display device configured to employ a pixel division method in which each pixel of a displayed image is configured with sub-pixels obtained by spatial division of one pixel in a division ratio may include: pixel formation portions provided correspondingly to respective pixels of the image, each portion configured to form a pixel of primary colors with the sub-pixels; a drive circuit configured to provide each portion with applied voltages respectively corresponding to the sub-pixels composing the pixel to be formed by that portion, based on a gradation value indicated by an input signal provided as a video signal representing the image; and a gamma correction part configured to correct a relationship between the gradation value indicated by the input signal and a luminance value of the pixel to be formed by that portion according to the gradation value independently for each of the primary colors.

1 - 10 . (canceled) 
     
     
         11 . A color liquid crystal display device configured to employ a pixel division method in which each pixel of an image displayed in a screen is configured with two or more sub-pixels obtained by spatial division of one pixel in a division ratio, the device comprising:
 a plurality of pixel formation portions provided correspondingly to respective pixels of the image, each of the pixel formation portions configured to form a pixel of any of primary colors for color display with the two or more sub-pixels;   a drive circuit configured to provide each of the pixel formation portions with applied voltages respectively corresponding to the two or more sub-pixels composing the pixel to be formed by that pixel formation portion, based on a gradation value indicated by an input signal provided from outside as a video signal representing the image; and   a gamma correction part configured to correct a relationship between the gradation value indicated by the input signal and a luminance value of the pixel to be formed by that pixel formation portion according to the gradation value independently for each of the primary colors for color display;   wherein each of the pixel formation portions forms the respective pixel by displaying the two or more sub-pixels with luminance values different from one another based on the applied voltages, and   wherein the gamma correction part corrects the relationship such that gradation dependence of chromaticity is suppressed when the screen is viewed from a front thereof, and also corrects the relationship in a vicinity of a predetermined gradation value such that the gradation dependence of chromaticity is suppressed when the screen is viewed from an oblique direction, the predetermined gradation value being determined by an area ratio of the two or more sub-pixels in the one pixel and differences in the applied voltages among the two or more sub-pixels.   
     
     
         12 . The color liquid crystal display device of  claim 11 , wherein the gamma correction part is configured to correct the chromaticity when viewed from the front to be shifted from a state maintaining a color balance toward blue in the vicinity of the gradation value such that the gradation dependence of chromaticity is suppressed when viewed from the oblique direction. 
     
     
         13 . The color liquid crystal display device of  claim 11 , wherein the gamma correction part is configured to correct the relationship such that a curve representing the gradation dependence of chromaticity when viewed from the front becomes approximately flat in a range except for the vicinity of the gradation value. 
     
     
         14 . The color liquid crystal display device of  claim 11 , wherein the gamma correction part is configured to correct the relationship such that a curve representing the gradation dependence of chromaticity when viewed from the front changes approximately monotonically with respect to the gradation value. 
     
     
         15 . The color liquid crystal display device of  claim 11 , wherein the gamma correction part includes a correction table associating a gradation value before correction with a gradation value after correction for each of the primary colors for color display in order to correct the relationship, and outputs the gradation value after correction associated with the gradation value indicated by the input signal referring to the correction table, and
 wherein the drive circuit is further configured to provide each of the pixel formation portions with the applied voltages based on the gradation value after correction.   
     
     
         16 . A gamma correction method for correcting a relationship between a gradation value indicated by an input signal provided from outside as a video signal representing an image and a luminance value of a pixel formed according to the gradation value, in a color liquid crystal display device employing a pixel division method in which each pixel of the image displayed on a screen is composed of two or more sub-pixels obtained by spatial division of one pixel in a division ratio, the method comprising:
 a correction to correct the relationship independently for each of primary colors for color display;   wherein in the correction, the relationship is corrected such that gradation dependence of chromaticity is suppressed when the screen is viewed from a front thereof, and the relationship in a vicinity of a predetermined gradation value is also corrected such that the gradation dependence of chromaticity is suppressed when the screen is viewed from an oblique direction, the predetermined gradation value being determined by an area ratio of the two or more sub-pixels in the one pixel and differences in voltages applied to liquid crystal of the color liquid crystal display device among the two or more sub-pixels.   
     
     
         17 . The gamma correction method of  claim 16 , wherein in the correction, the chromaticity when viewed from the front is corrected to shift from a state maintaining a color balance toward blue in the vicinity of the gradation value such that the gradation dependence of chromaticity is suppressed when viewed from the oblique direction. 
     
     
         18 . The gamma correction method of  claim 16 , wherein in the correction, the relationship is corrected such that a curve representing the gradation dependence of chromaticity when viewed from the front becomes approximately flat in a range except for the vicinity of the gradation value. 
     
     
         19 . The gamma correction method of  claim 16 , wherein in the correction, the relationship is corrected such that a curve representing the gradation dependence of chromaticity when viewed from the front changes approximately monotonically with respect to the gradation value.