Apparatus and method to improve a response speed of an LCD

• US 20030193460A1
• Filed: 11/20/2002
• Published: 10/16/2003
• Est. Priority Date: 04/10/2002
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Lee, Sang-Hak, Lee, Sang-Un
• Granted Patent: US 7,221,347 B2
• Time in Patent Office: Days
• US Class Current: 345/87
• CPC Class Codes: G09G 2320/0252 Improving the response speed
• CPC Class Codes: G09G 2320/0285 using tables for spatial correction of display data
• 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 2360/18 Use of a frame buffer in a display terminal, inclusive of the display panel
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers

Abstract

An apparatus and method thereof to improve a response speed of an LCD includes a noise rejection unit and a comparator. The noise rejection unit rejects noise in current digital image data and previous digital image data at a same pixel position as in the current digital image data. The comparator compares the current digital image data and the previous digital image data of which noises are rejected within a reference value, changes the current digital image data based on a comparison result, and outputs a result indicative thereof.

Claims

1. An apparatus to improve a response speed of an LCD, the apparatus comprising:

a noise rejection unit to reject noise in current digital image data and previous digital image data at a same pixel position as in the current digital image data; and

a comparator to compare the current digital image data and the previous digital image data of which noises are rejected within a reference value, to change the current digital image data based on a comparison result, and to output a result indicative thereof.

2. The apparatus of claim 1, wherein the noise rejection unit comprises:

a first low-pass filter (LPF) to reject a noise in the current digital image data; and

a second LPF to reject the noise in the previous digital image data at the same pixel position as in the current digital image data.

3. The apparatus of claim 1, wherein the comparator comprises a look up table (LUT) to hold gradation data that changes a response speed of the current digital image data.

4. The apparatus of claim 3, wherein the comparator accesses the LUT to output the current digital image data when a difference between gradations of the current digital image data and the previous digital image data, of which the noise is rejected, is smaller than the reference value.

5. The apparatus of claim 3, wherein the comparator compares the gradation of the current digital image data and the gradation of the previous digital image data, changes the current digital image data and outputs the result, when the difference between the gradations of the current digital image data and the previous digital image data of which the noise is rejected, is larger than the reference value.

6. The apparatus of claim 5, wherein the comparator accesses the LUT to increase the gradation of the current digital image data and outputs the result when the difference between the gradations of the current digital image data and the previous digital image data, of which the noise is rejected, is larger than the reference value and the gradation of the current digital image data is larger than the gradation of the previous digital image data.

7. The apparatus of claim 5, wherein the comparator accesses the LUT to decrease the gradation of the current digital image data and outputs the result when the difference between the gradation of the current digital image data and the previous digital image data, of which the noise is rejected, is larger than the reference value and the gradation of the current digital image data is smaller than the gradation of the previous digital image data.

8. An apparatus to improve a response speed of an LCD, comprising:

a buffer receiving digital image data and outputting first current image data;

a first noise rejection unit rejecting noise in the first current image data and outputting second current image data where noise is rejected;

a frame memory storing the first current image data and outputting first previous image data, which precedes the first current image data;

a second noise rejection unit outputting second previous image data indicative of noise rejected from the first previous image data;

a comparator comparing gradations of the first current image data, the second current image data, the first previous image data, and the second previous image data to output the digital image data having the improved response speed.

9. The apparatus of claim 8, wherein the comparator comprises a look up table (LUT) holding gradation data to change a response speed.

10. The apparatus of claim 8, wherein the first previous image data has a same pixel position as the first current image data.

11. The apparatus of claim 8, wherein the comparator compares a difference between the gradations of the second current image data and the second previous image data and, when the difference is smaller than a reference value, the comparator outputs the digital image data having a same response speed as the first current image data.

12. The apparatus of claim 8, wherein the comparator compares a difference between the gradations of the second current image data and the second previous image data and, when the difference is larger than a reference value, the comparator changes the response speed of the first current image data and outputs the digital image data indicative thereof.

13. The apparatus of claim 8, wherein when the gradation of the first current image data is larger than the gradation of the first previous image data, the comparator accesses a look up table (LUT) and outputs the digital image data having the response speed faster than the first current digital image data.

14. The apparatus of claim 8, wherein when the gradation of the first current image data is smaller than the gradation of the first previous image data, the comparator accesses a look up table (LUT) and outputs the digital image data having a response speed slower than that of the first current digital image data.

15. The apparatus of claim 8, wherein the comparator compares a difference between the gradations of the second current image data and the second previous image data and the comparator performs one of the digital image data having a same response speed as the first current image data when the difference is smaller than a reference value, changes the response speed of the first current image data and outputs the digital image data indicative thereof when the difference is larger than a reference value, and accesses a look up table (LUT) and outputs the digital image data having the response speed faster than the first current digital image data when the gradation of the first current image data is larger than the gradation of the first previous image data.

16. A method of improving response speed of an LCD, the method comprising:

rejecting noise in a previous digital image data at a same pixel position as a current digital image data;

comparing a difference between gradations of the current digital image data and the previous digital image data with a reference value and outputting a result indicative thereof; and

accessing an LUT storing gradation data that changes a response speed, to change the current digital image data based on the result.

17. The method of claim 16, wherein when accessing the LUT, the LUT is accessed to output the current digital image data when the difference between the gradations of the current digital image data and the previous digital image data, of which the noise is rejected, is smaller than the reference value.

18. The method of claim 17, wherein when accessing the LUT, the gradation of the current digital image data is compared with the gradation of the previous digital image data, the gradation of the current digital image data is changed based on the comparison result, and the result is output when the difference between the gradations of the current digital image data and the previous digital image data, of which the noise is rejected, is larger than the reference value.

19. The method of claim 18, wherein the LUT is accessed to increase the gradation of the current digital image data and output the result, when the difference between the gradations of the current digital image data and the previous digital image data, of which the noise is rejected, is larger than the reference value and the gradation of the current digital image data is larger than the gradation of the previous digital image data.

20. The method of claim 18, wherein the LUT is accessed to decrease the gradation of the current digital image data and output the result, when the difference between the gradations of the current digital image data and the previous digital image data, of which the noise is rejected, is larger than the reference value and the gradation of the current digital image data is smaller than the gradation of the previous digital image data.

21. A method to improve a response speed of an LCD, comprising:

outputting first current image data based on digital image data;

rejecting noise in the first current image data and outputting second current image data indicative thereof;

outputting first previous image data preceding the first current image data;

rejecting noise in the first previous image data and outputting second previous image data indicative thereof;

comparing a gradation of the second current image data and a gradation of the second previous image data; and

outputting the digital image data having a same response speed as the first current image data when a difference between the gradations of the second current image data and the second previous image data is smaller than a reference value.

22. A method to improve a response speed of an LCD, comprising:

outputting first current image data based on digital image data;

rejecting noise in the first current image data and outputting second current image data indicative thereof;

outputting first previous image data preceding the first current image data;

rejecting noise in the first previous image data and outputting second previous image data indicative thereof;

comparing a gradation of the second current image data and a gradation of the second previous image data; and

determining whether the gradation of the first current image data is larger than the gradation of the first previous image data when a difference between the gradations of the second current image data and the second previous image data is larger than a reference value.

23. The method of claim 22, further comprising:

outputting the digital image data having the response speed faster than the first current digital image data when the gradation of the first current image data is larger than the gradation of the first previous image data.

24. The method of claim 22, further comprising:

outputting the digital image data having a response speed slower than that of the first current digital image data when the gradation of the first current image data is smaller than the gradation of the first previous image data.