Column electrode driving circuit for use with image display device and image display device incorporating the same

• US 20010052897A1
• Filed: 06/19/2001
• Published: 12/20/2001
• Est. Priority Date: 06/19/2000
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Yanagi, Toshihiro, Nakano, Taketoshi, Kawaguchi, Takafumi
• Granted Patent: US 6,765,551 B2
• Time in Patent Office: Days
• US Class Current: 345/204
• CPC Class Codes: G09G 2310/027 Details of drivers for data electrodes, the drivers handling digital grey scale data, e.g. use of D/A converters
• CPC Class Codes: G09G 2320/0276 for the purpose of adaptation to the characteristics of a display device, i.e. gamma correction
• CPC Class Codes: G09G 3/2011 by amplitude modulation
• CPC Class Codes: G09G 3/3688 suitable for active matrices only
• CPC Class Codes: G09G 3/3696 Generation of voltages supplied to electrode drivers

Abstract

A column electrode driving circuit for an image display device for selecting, from among a plurality of reference voltage levels, reference voltage levels respectively corresponding to gray scale levels in input data, and outputting the respective selected voltage levels to at least one data line. The input data includes data of a first color, a second color, and a third color. The reference voltage levels are independently selected corresponding to the gray scale levels in the input data of the first, second, and third colors. Among the reference voltage levels independently selected corresponding to a given gray scale level in the input data of the first, second, and third colors, the reference voltage level selected corresponding to at least one color is different from the reference voltage level or levels selected corresponding to the other color or colors, the given gray scale level being within a predetermined range. The reference voltage level selected corresponding to the given gray scale level in the input data of the at least one color is equal to a reference voltage level selected corresponding to another gray scale level in the input data of the other color or colors.

Claims

1. A column electrode driving circuit for an image display device for selecting, from among a plurality of reference voltage levels, reference voltage levels respectively corresponding to gray scale levels in input data, and outputting the respective selected voltage levels to at least one data line, wherein the input data comprises data of a first color, a second color, and a third color, wherein:

the reference voltage levels are independently selected corresponding to the gray scale levels in the input data of the first color, the second color, and the third color;

among the reference voltage levels independently selected corresponding to a given gray scale level in the input data of the first color, the second color, and the third color, the reference voltage level selected corresponding to at least one color is different from the reference voltage level or levels selected corresponding to the other color or colors, the given gray scale level being within a predetermined range; and

the reference voltage level selected corresponding to the given gray scale level in the input data of the at least one color is equal to a reference voltage level selected corresponding to another gray scale level in the input data of the other color or colors.

2. A column electrode driving circuit according to

claim 1

, wherein:

among the reference voltage levels independently selected corresponding to a given gray scale level in the input data of the first color, the second color, and the third color, the reference voltage levels selected corresponding to the first color and the third color are shifted relative to the reference voltage level selected corresponding to the second color by a predetermined number of gray scale levels; and

the column electrode driving circuit provides a number of additional reference voltage levels for interpolation purposes, the number being equal to the predetermined number.

3. A column electrode driving circuit according to

claim 1

, wherein:

luminance values corresponding to gray scale levels of each of the first color, the second color, and the third color when displayed alone are normalized by a first max, a second max, and a third max, which respectively represent the maximum luminance values of the first color, the second color, and the third color when displayed alone; and

the reference voltage levels selected corresponding to the gray scale level are selected so that the luminance values for the first color, the second color, and the third color will coincide on the basis of gray scale levelluminance characteristics expressed in terms of the normalized luminance values.

4. A column electrode driving circuit according to

claim 1

, wherein the first color, the second color, and the third color are red, green, and blue, respectively.

5. A column electrode driving circuit according to

claim 1

, wherein the first color, the second color, and the third color are cyan, magenta, and yellow, respectively.

6. An image display device comprising the column electrode driving circuit according to

claim 1

.