DRIVING CIRCUIT APPARATUS

• US 20090096819A1
• Filed: 09/25/2008
• Published: 04/16/2009
• Est. Priority Date: 10/16/2007
• Status: Abandoned Application

• Current Assignee: LAPIS Semiconductor Co., Ltd. (ROHM Co., Ltd.)
• Original Assignee: OKI Electric Industry Company Limited
• Inventors: Kinoshita, Hiroyuki
• Application Number:
  US12/237,604
• Publication Number:
  US 20090096819A1
• Time in Patent Office: Days
• US Class Current: 345/694
• 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 2320/0285 using tables for spatial correction of display data
• CPC Class Codes: G09G 3/3685 Details of drivers for data electrodes
• CPC Class Codes: G09G 3/3696 Generation of voltages supplied to electrode drivers

Abstract

A driving circuit that reduces chip size of a source driver while maintaining image quality when image data is configured by multiple bits. The source driver provided in connection with a timing controller that converts image data into color data. The source driver displays an image by controlling pixel density of a liquid crystal panel. The source driver is divided into plural regions in units of pseudo linear elements to perform a gamma correcting operation based on a gamma characteristic. In the source driver a GMA voltage for each region is divided by resistive elements arranged between input signal lines. With respect to variation of plural divided GMA voltages, variation of the maximum high density region becomes coarser than variation of the maximum low density region in compliance with visual sensitivity of the density, thus reducing the number of input data lines of the source driver.

Claims

1. A driving circuit apparatus having a color density data conversion unit that converts image data into color density data and for displaying an image by controlling color density of pixels arranged in a matrix,

wherein a relationship between the image data at an input side of the color density data conversion unit and the color density data at an output side of the color density data conversion unit is nonlinear, the driving circuit apparatus is divided into plural regions in units of pseudo linear elements, and at least a resolution of a maximum high density region is set to be higher than a resolution of a maximum low density region in compliance with visual sensitivity of the color density.

2. The driving circuit apparatus according to claim 1, wherein a unique gamma characteristic for the pixels is reflected on the color data at the output side of the color density data conversion unit based on a predetermined look-up table.

3. A driving circuit apparatus having a color density data conversion unit that converts image data into color density data and for displaying an image by controlling density of pixels arranged in a matrix, comprising:

a region dividing unit that divides the driving circuit apparatus into plural regions in units of pseudo linear elements in order to perform a gamma correcting operation based on a nonlinear unique gamma characteristic representing a relationship between the color data and driving voltages representing color gray scales depending on the color data;

a driving voltage dividing unit that divides the driving voltages for each of the regions by resistors;

a driving voltage variation setting unit that, with respect to variation of the driving voltages divided by the resistors by the driving voltage dividing unit, makes at least variation of a maximum high density region coarser than variation of a maximum low density region in compliance with visual sensitivity of the density of pixels;

a driving voltage selecting unit that selects one driving voltage from the driving voltages set by the driving voltage dividing unit; and

a control unit that controls the density of pixels based on the driving voltage selected by the driving voltage selecting unit.

4. The driving circuit apparatus according to claim 3, wherein the unique gamma characteristic for the pixels is reflected on the color data at the output side of the color density data conversion unit based on a predetermined look-up table.

5. A driving circuit for displaying an image by controlling color density of pixels on a display, comprising:

a timing control circuit that converts received image data into color data to provide gamma voltages;

a gamma correction circuit including a network of resistance elements connected together in series, the gamma voltages being coupled to connecting nodes between the resistance elements, and predetermined ones of the connecting nodes providing driving voltages that are gamma corrected for output from the gamma correction circuit via data lines; and

a decoder coupled to the gamma correction circuit, that receives the driving voltages along the data lines and selects a driving voltage from the driving voltages for output to the display,

wherein differences between the driving voltages provided from adjacent ones of the data lines at a first end of the network of resistance elements are larger than differences between the driving voltages provided from adjacent ones of the data lines at a second end of the network of resistance elements.

6. A driving circuit for displaying an image by controlling color density of pixels on a display, comprising:

a timing control circuit that converts received image data into color data to provide gamma voltages;

a gamma correction circuit including a network of resistance elements connected together in series, the gamma voltages being coupled to connecting nodes between the resistance elements, and predetermined ones of the connecting nodes providing driving voltages that are gamma corrected for output from the gamma correction circuit via data lines; and

a decoder coupled to the gamma correction circuit, that receives the driving voltages along the data lines and selects a driving voltage from the driving voltages for output to the display,

wherein differences between the driving voltages provided from adjacent ones of the data lines at a first end of the network of resistance elements are larger than differences between the driving voltages provided from adjacent ones of the data lines at a second end of the network of resistance elements, and

wherein the driving voltages at the first end of the network of resistance elements are greater than the driving voltages at the second end of the network of resistance elements, so that the driving voltages that correspond to high density color have higher gradation than the driving voltages that correspond to low density color.