METHOD OF CONTROLLING A DIMMING OPERATION, DIMMING OPERATION CONTROL DEVICE, AND FLAT PANEL DISPLAY DEVICE HAVING THE SAME

• US 20140063078A1
• Filed: 06/28/2013
• Published: 03/06/2014
• Est. Priority Date: 08/30/2012
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Inventors: Choi, Yong-Seok, Chun, Byung-Ki, Park, Jong-Woong, Lee, Joo-Hyung
• Granted Patent: US 9,620,052 B2
• Time in Patent Office: Days
• US Class Current: 345/690
• CPC Class Codes: G09G 2320/0633 by amplitude modulation of the brightness of the illumination source
• CPC Class Codes: G09G 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• 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 3/20 for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
• CPC Class Codes: G09G 3/22 using controlled light sources
• CPC Class Codes: G09G 3/3208 organic, e.g. using organic light-emitting diodes [OLED]
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers

Abstract

A method of controlling a dimming operation is disclosed. In one aspect, the method includes determining the brightness of an input image frame based on input image data, determining an input dimming value based on the brightness of the input image frame, selectively performing the dimming operation is based on a comparison of an absolute value of a difference between the input dimming value and a current output dimming value against a predetermined threshold value, where a value generated by adjusting the current output dimming value by a predetermined adjustment value is output as a next output dimming value when performing the dimming operation, and the input dimming value is output as the next output dimming value when not performing the dimming operation.

Claims

1. A method of controlling a dimming operation, comprising:

determining the brightness of an input image frame based on input image data;

determining an input dimming value based on the brightness of the input image frame;

deciding whether or not to perform the dimming operation by comparing an absolute value of a difference between the input dimming value and a current output dimming value against a predetermined threshold value; and

outputting as a next output dimming value one of a value generated by adjusting the current output dimming value by a predetermined adjustment value when deciding to perform the dimming operation and

the input dimming value when deciding not to perform the dimming operation.

2. The method of claim 1, wherein determining the brightness of the input image frame includes:

converting the input image data corresponding to RGB data into a luminance signal including brightness information; and

setting the brightness of the input image frame as an average brightness after calculating the average brightness based on the luminance signal.

3. The method of claim 1, wherein determining the input dimming value includes:

selecting a dimming value matched to the brightness of the input image frame using a look-up table as the input dimming value.

4. The method of claim 1, wherein deciding whether to perform the dimming operation includes:

deciding to perform the dimming operation when the absolute value of the difference between the input dimming value and the current output dimming value is smaller than the predetermined threshold value; and

deciding not to perform the dimming operation when the absolute value of the difference between the input dimming value and the current output dimming value is greater than the predetermined threshold value.

5. The method of claim 1, wherein outputting the value generated by adjusting the current output dimming value by the predetermined adjustment value as the next output dimming value includes:

outputting as the next output dimming value one of a value generated by decreasing the current output dimming value by the predetermined adjustment value when the input dimming value is smaller than the current output dimming value and

a value generated by increasing the current output dimming value by the predetermined adjustment value when the input dimming value is greater than the current output dimming value.

6. The method of claim 1,

wherein the dimming operation corresponds to a local dimming operation, and

wherein the dimming operation is separately performed on respective regions of a display panel of a flat panel display device.

7. The method of claim 1,

wherein the dimming operation corresponds to a global dimming operation, and

wherein the dimming operation is simultaneously performed on an entire region of a display panel of a flat panel display device.

8. A dimming operation control device comprising:

a brightness detection block configured to receive input image data, and to determine the brightness of an input image frame based on the input image data;

an input dimming value determination block configured to determine an input dimming value based on the brightness of the input image frame; and

a dimming operation control block configured to decide whether or not to perform a dimming operation by comparing an absolute value of a difference between the input dimming value and a current output dimming value against a predetermined threshold value, to output as a next output dimming value one of a value generated by adjusting the current output dimming value by a predetermined adjustment value when deciding to perform the dimming operation and the input dimming value when deciding not to perform the dimming operation.

9. The device of claim 8, wherein the brightness detection block is configured to convert the input image data corresponding to RGB data into a luminance signal including brightness information, and to set the brightness of the input image frame as an average brightness after calculating the average brightness based on the luminance signal.

10. The device of claim 8, wherein the input dimming value determination block is configured to select a dimming value matched to the brightness of the input image frame using a look-up table as the input dimming value.

11. The device of claim 8,

wherein the dimming operation control block decides to perform the dimming operation when the absolute value of the difference between the input dimming value and the current output dimming value is smaller than the predetermined threshold value, and

wherein the dimming operation control block decides not to perform the dimming operation when the absolute value of the difference between the input dimming value and the current output dimming value is greater than the predetermined threshold value.

12. The device of claim 8,

wherein the dimming operation control block outputs a value generated by decreasing the current output dimming value by the predetermined adjustment value as the next output dimming value when the input dimming value is smaller than the current output dimming value, and

wherein the dimming operation control block outputs a value generated by increasing the current output dimming value by the predetermined adjustment value as the next output dimming value when the input dimming value is greater than the current output dimming value.

13. The device of claim 8,

wherein the dimming operation corresponds to a local dimming operation, and

wherein the dimming operation is separately performed on respective regions of a display panel of a flat panel display device.

14. The device of claim 8,

wherein the dimming operation corresponds to a global dimming operation, and

wherein the dimming operation is simultaneously performed on an entire region of a display panel of a flat panel display device.

15. A flat panel display device comprising:

a display panel including a plurality of pixels having respective organic light emitting diodes;

a scan driving unit configured to provide a scan signal to the pixels;

a data driving unit configured to provide a data signal to the pixels;

a power unit configured to provide a high power voltage and a low power voltage to the pixels;

a timing control unit configured to control the scan driving unit, the data driving unit, and the power unit; and

a dimming operation control unit configured to selectively perform a dimming operation by comparing an absolute value of a difference between an input dimming value and a current output dimming value against a predetermined threshold value when performing the dimming operation by controlling the power unit based on a brightness of an input image frame.

16. The device of claim 15, wherein the dimming operation control unit is coupled to the timing control unit.

17. The device of claim 15, wherein the dimming operation control unit is located in the timing control unit.

18. The device of claim 16, wherein the dimming operation control unit includes:

a brightness detection block configured to receive input image data, and to determine the brightness of the input image frame based on the input image data;

an input dimming value determination block configured to determine the input dimming value based on the brightness of the input image frame; and

a dimming operation control block configured to decide whether or not to perform the dimming operation by comparing the absolute value of the difference between the input dimming value and the current output dimming value against the predetermined threshold value, to output as a next output dimming value one of a value generated by adjusting the current output dimming value by a predetermined adjustment value when deciding to perform the dimming operation and the input dimming value when deciding not to perform the dimming operation.

19. A flat panel display device comprising:

a display panel including a plurality of pixels having respective liquid crystal layers;

a scan driving unit configured to provide a scan signal to the pixels;

a data driving unit configured to provide a data signal to the pixels;

a backlight unit configured to provide light to the display panel;

a timing control unit configured to control the scan driving unit, the data driving unit, and the backlight unit; and

a dimming operation control unit configured to selectively perform a dimming operation by comparing an absolute value of a difference between an input dimming value and a current output dimming value against a predetermined threshold value when performing the dimming operation by controlling the backlight unit based on a brightness of an input image frame.

20. The device of claim 19, wherein the dimming operation control unit is coupled to the timing control unit.

21. The device of claim 19, wherein the dimming operation control unit is located in the timing control unit.

22. The device of claim 20, wherein the dimming operation control unit includes:

a brightness detection block configured to receive an input image data from outside, and to determine the brightness of the input image frame based on the input image data;

an input dimming value determination block configured to determine the input dimming value based on the brightness of the input image frame; and

a dimming operation control block configured to decide whether or not to perform the dimming operation by comparing the absolute value of the difference between the input dimming value and the current output dimming value against the predetermined threshold value, to output as a next output dimming value one of a value generated by adjusting the current output dimming value by a predetermined adjustment value when deciding to perform the dimming operation and the input dimming value when deciding not to perform the dimming operation.