Controller driver, liquid crystal display apparatus using the same, and liquid crystal driving method

• US 20060152501A1
• Filed: 12/16/2005
• Published: 07/13/2006
• Est. Priority Date: 01/13/2005
• Status: Active Grant

• Current Assignee: Renesas Electronics Corporation
• Original Assignee: NEC Electronics Corporation (Renesas Electronics Corporation)
• Inventors: Nose, Takashi, Furihata, Hirobumi
• Granted Patent: US 7,660,010 B2
• Time in Patent Office: Days
• US Class Current: 345/204
• CPC Class Codes: G09G 2320/0252 Improving the response speed
• CPC Class Codes: G09G 2320/0261 in the context of movement of objects on the screen or movement of the observer relative to the screen
• CPC Class Codes: G09G 2320/0285 using tables for spatial correction of display data
• CPC Class Codes: G09G 2320/0613 The adjustment depending on the type of the information to be displayed
• CPC Class Codes: G09G 2340/02 Handling of images in compressed format, e.g. JPEG, MPEG
• CPC Class Codes: G09G 2340/16 Determination of a pixel data signal depending on the signal applied in the previous frame
• CPC Class Codes: G09G 3/2055 the pattern being varied in time
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence

Abstract

A controller driver includes a first compressor for compressing received image data to generate first compressed image data, a second compressor to generate second compressed image data, and an image memory capable of storing the second compressed image data of at least one frame. It also includes an overdrive processing unit for generating corrected image data where a tone value of the received image data is corrected from the first compressed image data or its expanded data and second compressed image data of one frame previous to the first compressed image data or its expanded data. The compression processing performed in the first compressor is the same as compression processing performed in the second compressor in compressing image data of one frame previous to the received image data.

Claims

1. A controller driver comprising:

a compressing unit compressing received image data to generate first compressed image data and second compressed image data;

an image memory capable of storing the second compressed image data of at least one frame; and

an overdrive processing unit receiving the first compressed image data or expanded data thereof and also receiving the second compressed image data of one frame previous to the first compressed image data or expanded data thereof, and generating corrected image data where a tone value of the received image data is corrected based on the data,

wherein the compressing unit changes compression processing performed in generating the first compressed image data and the second compressed image data with time, and

compression processing performed in generating the first compressed image data in the compressing unit is the same as compression processing performed in compressing image data of one frame previous to the received image data to generate the second compressed image data.

2. The controller driver according to claim 1, wherein

the compressing unit comprises:

a first compressor compressing the received image data to generate the first compressed image data and

a second compressor compressing the received image data to generate the second compressed image data,

wherein the first compressor and the second compressor change compression processing performed in generating the first compressed image data and the second compressed image data, respectively, with time, and

compression processing performed in the first compressor is the same as compression processing performed in the second compressor in compressing image data of one frame previous to the received image data.

3. The controller driver according to claim 2, wherein

the first compressor and the second compressor compress image data by dithering, and

a dither matrix applied to the first compressor in compressing the received image data is the same as a dither matrix applied to the second compressor in compressing image data of one frame previous to the received image data.

4. The controller driver according to claim 3, wherein the dither matrix applied to the second compressor is changed frame by frame.

5. The controller driver according to claim 4, wherein the dither matrix applied to the second compressor is a dither matrix of n×

n (n is an integer of 2 or greater), and the dither matrix applied to the second compressor is changed frame by frame among n² number of different dither matrixes obtained by displacing a dither coefficient of the n×

n dither matrix.

6. The controller driver according to claim 2, comprising:

an expander expanding the second compressed image data acquired from the image memory;

a first temporary data holding circuit capable of holding the second compressed image data output from the second compressor and accessible from the image memory; and

a second temporary data holding circuit capable of holding the second compressed image data output from the image memory and accessible from the expander.

7. The controller driver according to claim 2, comprising:

an expander capable of expanding the second compressed image data; and

a shift register storing the corrected image data,

wherein the shift register is connected to the image memory so as to acquire the second compressed image data of one line at a time from the image memory, and

the shift register is also connected to the expander so as to supply held data to the expander by shift operation.

8. The controller driver according to claim 2, comprising:

an expander capable of expanding the second compressed image data in a unit of line; and

a shift register storing the corrected image data,

wherein the shift register is connected to the expander so as to acquire image data of one line expanded from the second compressed image data at a time from the expander, and

the shift register is also connected to the overdrive processing unit so as to supply held data to the overdrive processing unit by shift operation.

9. A liquid crystal display apparatus including a controller driver and a liquid crystal display section driven by the controller driver, wherein the controller driver comprises:

a compressing unit compressing received image data to generate first compressed image data and second compressed image data;

an image memory capable of storing the second compressed image data of at least one frame; and

an overdrive processing unit receiving the first compressed image data or expanded data and also receiving second compressed image data of one frame previous to the first compressed image data or expanded data and generating corrected image data where a tone value of the received image data is corrected based on the data,

wherein the compressing unit changes compression processes performed in generating the first compressed image data and the second compressed image data with time, and

compression processing performed in generating the first compressed image data in the compressing unit is the same as compression processing performed in compressing image data of one frame previous to the received image data to generate the second compressed image data.

10. A liquid crystal driving method comprising:

receiving image data;

compressing the received image data to generate first compressed image data;

generating corrected image data where a tone value of the received image data is corrected based on the first compressed image data or expanded data thereof and second compressed image data of one frame previous to the first compressed image data or expanded data thereof,

wherein compression processing performed in generating the first compressed image data and the second compressed image data is changed with time, and

compression processing performed in generating the first compressed image data is the same as compression processing performed in compressing image data of one frame previous to the received image data to generate the second compressed image data.

11. The liquid crystal driving method according to claim 10, wherein

the first compressed image data and the second compressed image data are generated by dithering, and

a dither matrix applied in compressing the received image data to generate the first compressed image data is the same as a dither matrix applied in compressing image data of one frame previous to the received image data to generate the second compressed image data.

12. The liquid crystal driving method according to claim 11, wherein the dither matrix applied in generating the second compressed image data is changed with a dither matrix applied in generating compressed image data one frame previously.

13. The liquid crystal driving method according to claim 12, wherein the dither matrix applied in generating the second compressed image data is a dither matrix of n×

n (n is an integer of 2 or greater), and the dither matrix applied in generating the second compressed image data is changed frame by frame among n² number of different dither matrixes obtained by displacing a dither coefficient.