Apparatus and method for driving small-sized LCD device

• US 20060158416A1
• Filed: 01/14/2006
• Published: 07/20/2006
• Est. Priority Date: 01/15/2005
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Ku, Yong-Geun
• Granted Patent: US 7,760,174 B2
• Time in Patent Office: Days
• US Class Current: 345/98
• CPC Class Codes: G09G 2320/0252 Improving the response speed
• CPC Class Codes: G09G 2320/0257 Reduction of after-image effects
• CPC Class Codes: G09G 2320/041 Temperature compensation
• CPC Class Codes: G09G 2320/103 Detection of image changes, e.g. determination of an index representative of the image change
• CPC Class Codes: G09G 2340/145 related to small screens
• 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 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/2092 Details of a display terminals using a flat panel, the details relating to the control arrangement of the display terminal and to the interfaces thereto suitable for both CRT and flat panel G09G5/003; specific for a CRT G09G1/165
• CPC Class Codes: G09G 5/06 using colour palettes, e.g. look-up tables

Abstract

An apparatus and method for driving a small-sized or low-powered liquid crystal display (LCD) device are provided to reduce the amount of energy consumed in driving the LCD device while displaying a high-quality moving image on a small-sized LCD panel without distortion such as tailing or blurriness, where the apparatus includes a compensation unit, which compensates for first image data with reference to a predetermined lookup table (LUT) in response to a first input control signal in a first mode, the first image data being consecutively input to the apparatus; a storage unit, which updates and then stores the first image data and second image data and outputs one of the first image data or the second image data in response to a second input control signal, the second image data being consecutively input to the apparatus; an output unit, which outputs one of the first image data, the second image data, or the compensated first image data in response to an output control signal; and a control unit, which generates the first input control signal, the second input control signal, and the output control signal in response to a predetermined control signal.

Claims

1. An apparatus for driving a liquid crystal display (LCD) panel of an LCD device, the apparatus comprising:

a compensation unit, which compensates for first image data with reference to a predetermined lookup table (LUT) in response to a first input control signal in a first mode, the first image data being consecutively input to the apparatus;

a storage unit, which updates and then stores the first image data and second image data and outputs one of the first image data or the second image data in response to a second input control signal, the second image data being consecutively input to the apparatus;

an output unit, which outputs one of the first image data, the second image data, or the compensated first image data in response to an output control signal; and

a control unit, which generates the first input control signal, the second input control signal, and the output control signal in response to a predetermined control signal.

2. The apparatus of claim 1, wherein the storage unit outputs the first image data stored therein to the output unit in a second mode and outputs the second image data stored therein to the output unit in a third mode.

3. The apparatus of claim 1, wherein the compensation unit comprises:

an input controller, which determines whether to receive a frame of the first image data currently being input to the apparatus in response to the first input control signal, the frame being referred to as a current frame;

an LUT unit, which stores the predetermined LUT, searches the predetermined LUT for a compensation value, by which the current frame of the first image data is to be compensated for, with reference to the current frame and a frame of the first image data previously input to the apparatus, and outputs the searched compensation value, the frame being referred to as a previous frame; and

a compensation calculator, which generates the compensated first image data based on the current frame, the previous frame, and the compensation value.

4. The apparatus of claim 3, wherein the input controller controls the first image data to be input to the compensation unit in the first mode and prevents the first image data from being input to the compensation unit in any of the second and third modes and a fourth mode.

5. The apparatus of claim 3, wherein the LUT unit comprises a plurality of sub-LUT units, which store a plurality of sub-LUTs for a plurality of pixel data of the first image data, search the sub-LUTs for compensation values for the pixel data of the first image data with reference to pixel data of the current frame of the first image data and pixel data of the previous frame of the first image data, and output the searched compensation values,

wherein the sub-LUT units operate in parallel.

6. The apparatus of claim 3, wherein the LUT unit updates the predetermined LUT based on predetermined LUT data.

7. The apparatus of claim 3, wherein the LUT is a register.

8. The apparatus of claim 3, wherein the compensation value is an overshoot value for the current frame of the first image data.

9. The apparatus of claim 3, wherein the compensation calculator comprises:

a calculator, which performs a predetermined operation on the current frame of the first image data and the compensation value in response to a compensation control signal; and

a compensation controller, which generates the compensation control signal based on the current frame and the previous frame of the first image data.

10. The apparatus of claim 9, wherein the calculator adds the compensation value to the current frame of the first image data in response to the compensation control signal if the level of the current frame of the first image data is higher than the level of the previous frame of the first image data, subtracts the compensation value from the current frame of the first image data if the level of the current frame of the first image data is lower than the level of the previous frame of the first image data, and maintains the current frame of the first image data if the level of the current frame of the first image data is the same as the level of the previous frame of the first image data.

11. The apparatus of claim 9, wherein the calculator comprises a plurality of sub-calculators, which compensate for the pixel data of the current frame of the first image data by performing a predetermined operation on the pixel data of the current frame of the first image data with the respective compensation value,

wherein the sub-calculators operate in parallel.

12. The apparatus of claim 9, wherein the compensation calculator further comprises a compensation image storage, which comprises a plurality of registers that stores compensated pixel data of the current frame of the first image data obtained by the sub-calculators,

wherein the compensated image storage outputs the compensated pixel data of the current frames of the first image data in series.

13. The apparatus of claim 3, wherein the output unit comprises:

a first output selector, which outputs one of the current frame of the first image data and the compensated current frame of the first image data in response to the output control signal;

an output adjustor, which delays the output of the first output selector for a predetermined amount of time; and

a second output selector, which outputs one of the output of the first output selector or the output of the storage unit in response to the output control signal.

14. The apparatus of claim 13, wherein the first output selector selects and then outputs the compensated first image data in the first mode and selects and then outputs the non-compensated first image data in the fourth mode.

15. The apparatus of claim 13, wherein the output adjustor is a latch.

16. The apparatus of claim 13, wherein the second output selector selects and then outputs the output of the output adjustor in one of the first or fourth modes and selects and then outputs the output of the storage unit in one of the second or third modes.

17. The apparatus of claim 1, wherein the first image data is moving image data, and the second image data is still image data.

18. The apparatus of claim 1, wherein the first mode is a moving image compensation mode, the second mode is a regular moving image mode, the third mode is a still image mode, and the fourth mode is a bypass mode.

19. A method of driving a liquid crystal display (LCD) panel of a LCD device, the method comprising:

storing first image data and second image data, which are consecutively input;

compensating for the first image data with reference to a predetermined lookup table (LUT) based on a result of comparing the current frame of the first image data with a previous frame of the first image data and delaying and then outputting the compensated first image data in a first mode;

outputting the stored first image data in a second mode;

outputting the stored second image data in a third mode; and

delaying and then outputting the first image data in a fourth mode.

20. The method of claim 19, wherein the compensating of the first image data comprises:

searching the predetermined LUT for a compensation value, by which the first image data is to be compensated for, with reference to the current and previous frames of the first image data; and

performing a predetermined operation on the compensation value and the current frame of the first image data based on the result of comparing the current frame and the previous frame of the first image data.

21. The method of claim 20, wherein the performing of the predetermined operation on the compensation value and the current frame of the first image data comprises:

adding the compensation value to the first image data if the level of the current frame of the first image data is higher than the level of the previous frame of the first image data;

subtracting the compensation value from the first image data if the level of the current frame of the first image data is lower than the level of the previous frame of the first image data; and

maintaining the first image data if the level of the current frame of the first image data is the same as the level of the previous frame of the first image data.

22. The method of claim 19, wherein the first image data is moving image data, and the second image data is still image data.

23. The method of claim 19, wherein the first mode is a moving image compensation mode, the second mode is a regular moving image mode, the third mode is a still image mode, and the fourth mode is a bypass mode.