DISPLAY DEVICE AND DRIVING METHOD THEREOF

• US 20090109165A1
• Filed: 05/28/2008
• Published: 04/30/2009
• Est. Priority Date: 10/31/2007
• Status: Abandoned Application

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Inventors: Kim, Myeong-Su, Choi, Kyung-Uk, Park, Yun-Jae, PARK, Mun-Soo
• Application Number:
  US12/128,537
• Publication Number:
  US 20090109165A1
• Time in Patent Office: Days
• US Class Current: 345/102
• CPC Class Codes: G09G 2320/0209 Crosstalk reduction, i.e. to reduce direct or indirect influences of signals directed to a certain pixel of the displayed image on other pixels of said image, inclusive of influences affecting pixels in different frames or fields or sub-images which constitute a same image, e.g. left and right images of a stereoscopic display
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/3426 the different display panel areas being distributed in two dimensions, e.g. matrix

Abstract

A backlight unit for a display device that reduces power consumption while and display of undesirable artifacts in images is presented. The backlight unit is divided into a plurality of light-emitting regions, and a luminance control signal generator controls the luminance of light emitted by each of the light-emitting regions. The luminance of a particular light-emitting region is controlled by taking into account light interference from an adjacent light-emitting region. A display panel to display images through light emitted from the backlight unit, and a backlight driver drives the backlight unit.

Claims

1. A display device comprising:

a backlight unit including a plurality of light-emitting regions including a first light emitting region and a second light emitting region that is adjacent to the first light-emitting region;

a display panel displaying images by using light emitted from the backlight unit;

a backlight driver driving the backlight unit; and

a luminance control signal generator controlling a luminance of the first light-emitting region according to an amount of light interference between the first light-emitting region and the second light-emitting region.

2. The display device of claim 1, wherein the luminance control signal generator comprises:

a luminance extractor to generate a luminance value of each of the light-emitting regions in response to pixel data signals;

a luminance compensator to compute an interference value corresponding to the luminance value and to generate a compensation value, wherein the interference value indicates the amount of light interference; and

a dimming calculator to generate a dimming signal corresponding to the compensation value and to supply the dimming signal to the backlight driver.

3. The display device of claim 2, wherein the interference value is between about 5% and about 30% of the luminance value.

4. The display device of claim 2, wherein the luminance control signal generator compares the compensation value with a predetermined maximum luminance value corresponding to a maximum current level that is allowed for each of the light-emitting regions, generates the dimming signal corresponding to the compensation value when the compensation value is less than the maximum luminance value, and generates the dimming signal corresponding to the predetermined maximum luminance value when the compensation value is equal to or greater than the predetermined maximum luminance value.

5. The display device of claim 4, wherein the backlight driver further comprises:

a pulse width modulation (“

PWM”

) signal generator to generate PWM signals having a duty ratio corresponding to the dimming signal; and

a light-emitting diode (“

LED”

) driver to control an electric current according to the duty ratio of the PMW signals.

6. The display device of claim 5, wherein there are a plurality of backlight drivers including the backlight driver, wherein the number of the backlight drivers is equal to the number of the light-emitting regions.

7. The display device of claim 1, wherein the backlight unit comprises at least one LED in each of the light-emitting regions.

8. The display device of claim 7, wherein the backlight unit further comprises a plurality of LEDs electrically connected to each other in series in each of the light-emitting regions.

9. The display device of claim 7, wherein the LED comprises a white LED.

10. The display device of claim 7, wherein the backlight unit further comprises a red LED, a green LED, and a blue LED in each of the light-emitting regions.

11. The display device of claim 10, wherein the backlight unit comprises a plurality of red LEDs, a plurality of green LEDs, and a plurality of blue LEDs electrically connected in series to the same color LEDs, and

the backlight driver drives the red LED, the green LED, and the blue LED in color groups, each color group having LEDs of the same color.

12. The display device of claim 1, further comprising:

a light sensor to measure a luminance of the backlight unit; and

a sensor signal modulator to modulate a light detect signal provided from the light sensor and to supply the light detect signal to the luminance control signal generator.

13. A method of driving a display device comprising:

computing a luminance value of each of light-emitting regions in a backlight unit;

computing a compensation value for each of the light-emitting regions;

generating a dimming control signal corresponding to the compensation value; and

supplying light corresponding to the dimming signal to each of the light-emitting regions.

14. The method of claim 13, wherein the computing of the compensation value further comprises adding the luminance value to an interference value, wherein the interference value indicates an amount of interference between light from adjacent display regions.

15. The method of claim 14, wherein the generating of the dimming signals further comprises:

comparing the compensation value with a predetermined maximum luminance value;

generating the dimming signal corresponding to the predetermined maximum luminance value when the compensation value is equal to or greater than the predetermined maximum luminance value; and

generating the dimming signal corresponding to the compensation value when the compensation value is less than the predetermined maximum luminance value.

16. The method of claim 15, wherein the generating of light comprises:

generating a PWM signal having a duty ratio corresponding to the dimming signal; and

supplying an electric current corresponding to the duty ratio to each of the light-emitting regions.

17. The method of claim 16, wherein the supplying the electric current comprises:

measuring a luminance corresponding to each of the light-emitting regions; and

comparing the measured luminance with the compensation value to control the luminance of the backlight unit.