Automatic image luminance control with backlight adjustment

• US 20050057484A1
• Filed: 09/15/2003
• Published: 03/17/2005
• Est. Priority Date: 09/15/2003
• Status: Abandoned Application

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Diefenbaugh, Paul S., Wyatt, David A.
• Application Number:
  US10/663,316
• Publication Number:
  US 20050057484A1
• Time in Patent Office: Days
• US Class Current: 345/102
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• CPC Class Codes: G09G 2320/0666 for control of colour parameters, e.g. colour temperature
• CPC Class Codes: G09G 2320/0673 for control of gamma adjustment, e.g. selecting another gamma curve
• CPC Class Codes: G09G 2360/144 the light being ambient light
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336

Abstract

Methods and apparatuses for adjusting backlight intensity in a display device of a computer system, and compensating with image brightness adjustments via graphics controller color-lookup table to retain a net equivalent level of brightness as perceived by the user when viewing images produced by the graphics controller on the display device.

Claims

1. A method comprising:

determining an ambient light level for an operating environment of a display device having an adjustable backlight to provide variable brightness; and

modifying a color brightness of one or more portions of an image to be displayed on the display device based on the ambient light level.

2. The method of claim 1 further comprising modifying the backlight intensity based on the modified color brightness.

3. The method of claim 2 wherein modification to the backlight intensity approximately offsets the modification to the color brightness.

4. The method of claim 1 wherein determining the ambient light level comprises receiving a signal from an ambient light sensor indicating the ambient light level.

5. The method of claim 1 wherein determining the ambient light level comprises receiving a user input.

6. The method of claim 1 wherein modifying the color brightness comprises modifying a color look-up table.

7. The method of claim 2 wherein modifying the backlight intensity comprises modifying a pulse width modulation signal that controls backlight illumination.

8. The method of claim 2 wherein modifying the backlight intensity comprises:

determining a hardware register value corresponding to a baseline backlight intensity value;

applying a software generated value to the register value to generate a modified backlight intensity value; and

using the modified backlight intensity value to the cause the backlight intensity to be modified.

9. The method of claim 8 wherein the baseline backlight intensity value is determined based on a user provided input.

10. The method of claim 8 wherein the baseline backlight intensity value is determined based on a power state of the display device.

11. The method of claim 8 wherein the hardware register value is stored in a register within a Peripheral Component Interconnect configuration space.

12. A method comprising:

determining an ambient light level for a display device having an adjustable backlight to provide variable backlight intensity;

modifying the backlight intensity based on the ambient light level; and

modifying a color brightness or one or more portions of an image to be displayed on the display device based on the modified intensity of the adjustable backlight.

13. The method of claim 12 wherein modification to the color brightness approximately offsets the modification to the backlight intensity.

14. The method of claim 12 wherein determining the ambient light level comprises receiving a signal from an ambient light sensor indicating an ambient light level.

15. The method of claim 12 wherein determining the ambient light level comprises receiving a user input.

16. The method of claim 12 wherein modifying the color brightness comprises modifying the color brightness comprises modifying a pixel color using a graphics controller look-up table prior to passing the pixel to the display device.

17. The method of claim 12 wherein modifying the backlight intensity comprises modifying a pulse width modulation signal that controls backlight illumination.

18. The method of claim 12 wherein modifying the backlight intensity comprises:

determining a hardware register value corresponding to a baseline backlight intensity value;

applying a software generated value to the register value to generate a modified backlight intensity value; and

using the modified backlight intensity value to the cause the backlight intensity to be modified.

19. The method of claim 18 wherein the baseline backlight intensity value is determined based on a user provided input.

20. The method of claim 18 wherein the baseline backlight intensity value is determined based on a power state of the display device.

21. The method of claim 18 wherein the hardware register value is stored in a register within a Peripheral Component Interconnect configuration space.

22. An apparatus comprising:

an ambient light sensor to generate signals indicating a sensed ambient light level;

a display device having an adjustable backlight source; and

a graphics control device coupled with the ambient light sensor on the display device, the graphics control device to modify image brightness and backlight intensity based on the sensed ambient light level.

23. The apparatus of claim 22 wherein the graphics control device modifies image brightness for one or more portions of an image to be displayed on the display device based on the sensed ambient light level and to modify the backlight intensity based on the modified image brightness.

24. The apparatus of claim 22 wherein the graphics control device modifies backlight intensity based on the sensed ambient light level and modifies the color brightness for one or more portions of an image to be displayed on the display device based on the modified backlight intensity.

25. The apparatus of claim 22 wherein the display device comprises a flat-panel liquid crystal display.

26. The apparatus of claim 22 wherein the display device comprises a plasma display device.

27. The apparatus of claim 22 wherein the graphics control device comprises:

a backlight control circuit coupled with the adjustable backlight source to control the intensity of backlight provided by the adjustable backlight source; and

a display control circuit coupled with the ambient light sensor and the backlight control circuit to apply an adjustment to a baseline backlight including at least the sensed ambient light level to generate a modified backlight intensity signal;

wherein the backlight control circuit causes the adjustable backlight source to provide a backlight intensity corresponding to the modified backlight intensity value.

28. The apparatus of claim 27 wherein the backlight control circuit provides a pulse width modulated signal to the adjustable backlight source to control the intensity of the backlight provided by the adjustable backlight source.

29. The apparatus of claim 27 wherein the baseline backlight intensity is retrieved from a register coupled with the backlight controller.

30. The apparatus of claim 27 wherein the adjustment to the baseline backlight intensity further comprises user-specified adjustment parameters.

31. The apparatus of claim 30 wherein the user-specified adjustment parameters comprise a range of desired backlight adjustments.

32. An article comprising a computer-readable medium having stored thereon instructions that, when executed, cause one or more processing devices to:

determine an ambient light level for a display device having an adjustable backlight to provide variable backlight intensity; and

modify a color brightness of one or more portions of an image to be displayed on the display device based on the ambient light level.

33. The article of claim 32 further comprising instructions that, when executed, cause the one or more processing devices to modify the backlight intensity based on the modified color brightness.

34. The article of claim 33 wherein modification to the backlight intensity approximately offsets the modification to the color brightness.

35. The article of claim 32 wherein the instructions that cause the one or more processing devices to determine the ambient light level comprise instructions that, when executed, cause the one or more processing devices to receive a signal from an ambient light sensor indicating the ambient light level.

36. The article of claim 32 wherein the instructions that cause the one or more processing devices to determine the ambient light level comprise instructions that, when executed, cause the one or more processing devices to receive a user input.

37. The article of claim 32 wherein the instructions that cause the one or more processing devices to modify the color brightness comprise instructions that, when executed, cause the one or more processing devices to adjust the pixel luminance, using color look-up table.

38. The article of claim 33 wherein the instructions that cause the one or more processing devices to modify the backlight intensity comprise instructions that, when executed, cause the one or more processing devices to modify a pulse width modulation signal that controls backlight illumination.

39. The article of claim 33 wherein the instructions that cause the one or more processing devices to modify the backlight intensity further comprise instructions that, when executed, cause the one or more processing devices to:

determine a hardware register value corresponding to a baseline backlight intensity value;

apply a software generated value to the register value to generate a modified backlight intensity value; and

use the modified backlight intensity value to the cause the backlight intensity to be modified.

40. The article of claim 39 wherein the baseline backlight intensity value is determined based on a user provided input.

41. The article of claim 39 wherein the baseline backlight intensity value is determined based on a power state of the display device.

42. An article comprising a computer-readable medium having stored thereon instructions that, when executed, cause one or more computing devices to:

determine an ambient light level for a display device having an adjustable backlight to provide variable backlight intensity;

modify the backlight intensity based on the ambient light level; and

modify a color brightness or one or more portions of an image to be displayed on the display device based on the modified intensity of the adjustable backlight.

43. The article of claim 42 wherein modification to the color brightness approximately offsets the modification to the backlight intensity.

44. The article of claim 42 wherein the instructions that cause the one or more processing devices to determine the ambient light level comprise instructions that, when executed, cause the one or more processing devices to receive a signal from an ambient light sensor indicating an ambient light level.

45. The article of claim 42 wherein the instructions that cause the one or more processing devices to determine the ambient light level comprise instructions that, when executed, cause the one or more processing devices to receive user input.

46. The article of claim 42 wherein the instructions that cause the one or more processing devices to modify the color brightness comprise instructions that, when executed, cause the one or more processing devices to adjust the pixel luminance, using color look-up table.

47. The article of claim 42 wherein the instructions that cause the one or more processing devices to modify the backlight intensity comprise instructions that, when executed, cause the one or more processing devices to modify a pulse width modulation signal that controls backlight illumination.

48. The article of claim 42 wherein the instructions that cause the one or more processing devices to modify the backlight intensity comprise instructions that cause the one or more processing devices to:

determine a hardware register value corresponding to a baseline backlight intensity value;

apply a software generated value to the register value to generate a modified backlight intensity value; and

use the modified backlight intensity value to the cause the backlight intensity to be modified.

49. The article of claim 48 wherein the baseline backlight intensity value is determined based on a user provided input.

50. The article of claim 48 wherein the baseline backlight intensity value is determined based on a power state of the display device.

51. A system comprising:

a bus;

an ambient light sensor coupled with the bus to generate signals indicating a sensed ambient light level;

an input/output controller coupled with the bus;

a display device having an adjustable backlight source; and

a graphics control device coupled with the ambient light sensor, the bus and the display device, the graphics control device to modify image brightness and backlight intensity based on the sensed ambient light level.

52. The system of claim 51 wherein the graphics control device modifies image brightness for one or more portions of an image to be displayed on the display device based on the sensed ambient light level and to modify the backlight intensity based on the modified image brightness.

53. The system of claim 51 wherein the graphics control device modifies backlight intensity based on the sensed ambient light level and modifies the color brightness for one or more portions of an image to be displayed on the display device based on the modified backlight intensity.

54. The system of claim 51 wherein the display device comprises a flat-panel liquid crystal display.

55. The system of claim 51 wherein the display device comprises a plasma display device.

56. The system of claim 51 wherein the graphics control device comprises:

a backlight control circuit coupled with the adjustable backlight source to control the intensity of backlight provided by the adjustable backlight source; and

a display control circuit coupled with the ambient light sensor and the backlight control circuit to apply an adjustment to a baseline backlight including at least the sensed ambient light level to generate a modified backlight intensity signal;

wherein the backlight control circuit causes the adjustable backlight source to provide a backlight intensity corresponding to the modified backlight intensity value.

57. The system of claim 56 wherein the backlight control circuit provides a pulse width modulated signal to the adjustable backlight source to control the intensity of the backlight provided by the adjustable backlight source.

58. The system of claim 56 wherein the baseline backlight intensity is retrieved from a register coupled with the backlight controller.

59. The system of claim 56 wherein the adjustment to the baseline backlight intensity further comprises user-specified adjustment parameters.

60. The system of claim 59 wherein the user-specified adjustment parameters comprise a range of desired backlight adjustments.