Color Liquid Crystal Display Device and Gamma Correction Method for the Same
First Claim
1. A color liquid crystal display device employing a pixel division method in which each pixel of an image displayed in a predetermined screen is configured with a predetermined number of two or more sub-pixels obtained by spatial or temporal division of one pixel in a predetermined division ratio, the device comprising:
- a plurality of pixel formation portions provided correspondingly to respective pixels of the image, each of the portions forming a pixel of any of primary colors for color display with the predetermined number of sub-pixels;
a drive circuit for providing each of the pixel formation portion with applied voltages respectively corresponding to the 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 for correcting a relationship between a gradation value indicated by the input signal and a luminance value of the pixel formed by the 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 pixel by displaying the predetermined number of sub-pixels with luminance values different from one another based on the applied voltages, andwherein 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 the vicinity of a predetermined gradation value, which is determined by the division ratio in the one pixel and differences in the applied voltage among the predetermined number of sub-pixels, such that the gradation dependence of the chromaticity is suppressed when the screen is viewed from a predetermined oblique direction.
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Abstract
In one embodiment of the present application, a color liquid crystal display device is disclosed which can realize display having a high color reproducibility when a screen is viewed from an oblique direction as well as from a front direction, while improving a viewing angle dependence of γ-characteristics by employing a pixel division method. Gamma correction is carried out as follows independently for each R, G, and B with reference to R, G, and B correction tables so as to obtain a good color tracking. That is, the gamma correction is carried out such that chromaticity in the front view is shifted toward blue in an oblique hue correction range, which is determined by a pixel division ratio and the like, so as to reduce a shift of the chromaticity in the oblique view toward yellow in the oblique hue correction range, while maintaining a color balance in the other range (a gradation value range of 32 to 255 except for the oblique hue correction range). The present invention is suitable for a color liquid crystal display device employing the pixel division method.
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Citations
10 Claims
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1. A color liquid crystal display device employing a pixel division method in which each pixel of an image displayed in a predetermined screen is configured with a predetermined number of two or more sub-pixels obtained by spatial or temporal division of one pixel in a predetermined division ratio, the device comprising:
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a plurality of pixel formation portions provided correspondingly to respective pixels of the image, each of the portions forming a pixel of any of primary colors for color display with the predetermined number of sub-pixels; a drive circuit for providing each of the pixel formation portion with applied voltages respectively corresponding to the 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 for correcting a relationship between a gradation value indicated by the input signal and a luminance value of the pixel formed by the 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 pixel by displaying the predetermined number of 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 the vicinity of a predetermined gradation value, which is determined by the division ratio in the one pixel and differences in the applied voltage among the predetermined number of sub-pixels, such that the gradation dependence of the chromaticity is suppressed when the screen is viewed from a predetermined oblique direction. - View Dependent Claims (2, 3, 4, 5, 6)
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7. 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 predetermined screen is composed of a predetermined number of two or more sub-pixels obtained by spatial or temporal division of one pixel in a predetermined division ratio, the method comprising
a correction step of correcting the relationship independently for each of primary colors for color display, wherein in the correction step, 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 the vicinity of a predetermined gradation value is also corrected such that the gradation dependence of the chromaticity is suppressed when the screen is viewed from a predetermined oblique direction, the predetermined gradation value being determined by the division ratio in the one pixel and differences in a voltage applied to liquid crystal among the predetermined number of sub-pixels.
Specification