Power Management For Modulated Backlights

• US 20110175949A1
• Filed: 09/15/2009
• Published: 07/21/2011
• Est. Priority Date: 09/30/2008
• Status: Abandoned Application

• Current Assignee: Dolby Laboratories Licensing Corporation (Dolby Laboratories Incorporated)
• Original Assignee: Dolby Laboratories Licensing Corporation (Dolby Laboratories Incorporated)
• Inventors: Messmer, Neil Wynn, Wallener, Damir
• Application Number:
  US13/119,989
• Publication Number:
  US 20110175949A1
• Time in Patent Office: Days
• US Class Current: 345/690
• 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 2320/0686 with two or more screen areas displaying information with different brightness or colours
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/342 using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines
• CPC Class Codes: G09G 3/36 using liquid crystals

Abstract

Power levels of a backlight are adjusted in a number of ways and based on a number of criteria. The adjustments result in a lower power consumption and, in some cases, may enhance audience attention to important objects in a scene. The adjustments comprise, for example, a combination of ramping down power (lowering final display brightness) in concert with corresponding compensatory LCD adjustments (increasing final display brightness). The adjustments may also include, for example, system dimming after ramp down/LCD adjustments are exhausted, or the shifting of an LDR2HDR curve.

Claims

1. A display, comprising:

a backlight comprising a set of individually controllable light sources;

a modulator configured position to modulate light emitted from the backlight to form an image; and

a processing device configured to receive an image signal and, based on the image signal, adjust a brightness of at least one region of light sources in the backlight and at least one corresponding region of pixels in the modulator to reduce power consumption.

2. The display according to claim 1, wherein the adjustment comprises a ramp down of the entire backlight and a corresponding increased opening adjustment of the modulator such that a brightness level of a resulting display is essentially unchanged.

3. The display according to claim 2, wherein the adjustment further comprises a global dimming if the ramp down &

opening adjustments do not result in a desired decrease in power consumption.

4. The display according to claim 1, wherein the adjustment comprises an adjustment of a relative brightness of a Region Of Interest (ROI) compared to other areas of an image being displayed.

5. The display according to claim 4, wherein the ROI comprises an area in a scene being displayed that has a higher degree of focus compared to the other areas of the scene.

6. The display according to claim 4, wherein the ROI is determined by examination of a series of frames of video images.

7. The display according to claim 1, wherein the adjustment comprises a shifting of an LDR2HDR curve used to expand image data of the image signal.

8. The display according to claim 1, wherein the adjustment comprises an adjustment of an, LDR2HDR curve used to expand image data of the image signal.

9. The display according to claim 8, wherein the adjustment comprises a change in at least one of a slope, gradient, locus, starting point, midpoint, and ending point of the LDR2HDR curve.

10. The display according to claim 1, wherein the adjustment comprises a replacement of an LDR2HDR curve used to expand image data of the image signal.

11. A method, comprising the steps of:

monitoring a power consumption of a display;

if the monitored power exceeds a maximum power threshold, then,

ramping down an amount of power provided to a backlight of the display, and

simultaneously increasing an amount of opening in light valves of a front modulator such that a brightness of the display is not diminished.

12. The method according to claim 11, further comprising the step of globally dimming the backlight if the power consumption of the display has not been reduced to a desired level.

13. The method according to claim 11, wherein the steps of ramping down and simultaneously increasing are performed until the power consumption of the display decreases to a specified reduction threshold.

14. The method according to claim 13, wherein the specified reduction threshold is lower than the maximum power threshold.

15. A method, comprising the steps of:

identifying a Region Of Interest (ROI) in an image being displayed; and

adjusting an amount of brightness in the ROI based on a content of the ROI.

16. The method according to claim 15, wherein the ROI comprises a region of strong white content.

17. The method according to claim 16, further comprising the step of characterizing the ROI, wherein the step of adjustment comprises adjusting the amount of brightness based on the characterization.

18. The method according to claim 16, wherein the step of adjusting comprises applying a brightness calculation to the ROI.

19. An electronically readable media comprising a set of instructions stored thereon, that, when loaded into a processing device, cause the processing device to perform the steps of claim 11.

20. The electronically readable media according to claim 19, wherein the step of replacing the LDR2HDR curve comprises shifting the LDR2HDR curve.

21. The electronically readable media according to claim 19, wherein the step of replacing the LDR2HDR curve comprises selecting a new LDR2HDR curve.

22. The electronically readable media according to claim 19, wherein the electronically readable media is configured to be a component in a dual modulation backlight LCD display.

19-1. An electronically readable media comprising a set of instructions stored thereon, that, when loaded into a processing device, cause the processing device to perform the steps of:

monitoring a power level; and

replacing an LDR2HDR curve used to expand a range of image data if the monitored power level exceeds a predetermined threshold.