DISPLAY BRIGHTNESS CONTROL BASED ON AMBIENT LIGHT ANGLES

• US 20120019152A1
• Filed: 09/30/2010
• Published: 01/26/2012
• Est. Priority Date: 07/26/2010
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Barnhoefer, Ulrich T., Chen, Wei
• Granted Patent: US 8,686,981 B2
• Time in Patent Office: Days
• US Class Current: 315/158
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2320/0653 Controlling or limiting the speed of brightness adjustment of the illumination source
• CPC Class Codes: G09G 2360/144 the light being ambient light
• CPC Class Codes: H05B 41/3922 and measurement of the incident light
• CPC Class Codes: H05B 45/12 using optical feedback

Abstract

Methods and devices are provided for controlling the brightness of a display for an electronic device based on ambient light conditions. In one embodiment, an electronic device may employ one or more brightness adjustment profiles for changing the brightness of a display based on ambient light levels and/or the angle of incidence of one or more ambient light sources. In certain embodiments, one or more ambient light sensors may be designed to perceive the ambient light level differently based on the angle of incidence of a light source. The perceived ambient light level may then be used to adjust the display brightness based on the one or more brightness adjustment profiles. In other embodiments, one or more ambient light sensors may be designed to detect the angle of incidence of an ambient light source. In these embodiments, the detected angle and the ambient light level may be used to adjust the display brightness.

Claims

1. An electronic device, comprising:

a display comprising a backlight;

a sensing device configured to detect an ambient light angle; and

a display controller operably coupled to the backlight and configured to adjust a brightness of the backlight based on the detected ambient light angle.

2. The electronic device of claim 1, wherein the sensing device comprises an ambient light sensor.

3. The electronic device of claim 1, wherein the sensing device comprises a camera.

4. The electronic device of claim 1, comprising a user interface configured to receive a user input that selects an angular adjustment profile for the backlight, wherein the angular adjustment profiles specifies angular adjustments to the brightness based on the detected ambient light angle.

5. The electronic device of claim 1, comprising one or more ambient light sensors configured to detect an ambient light level, wherein the display controller is configured to adjust the brightness based on the detected ambient light level.

6. An electronic device, comprising:

a display comprising a backlight;

one or more ambient light sensors configured to detect a level of ambient light and an angle of incidence of the ambient light; and

a display controller operably coupled to the backlight and configured to adjust the detected level of ambient light based on the angle of incidence to produce an adjusted ambient light level and to adjust a brightness of the backlight based on the adjusted ambient light level.

7. The electronic device of claim 6, wherein the adjusted ambient light level is approximately equal to the detected level of ambient light multiplied by the cosine of the angle of incidence.

8. The electronic device of claim 6, wherein the adjusted ambient light level is approximately equal to or greater than the detected level of ambient light multiplied by the cosine of the angle of incidence and less than the detected level of ambient light when the angle of incidence is greater than or less than ninety degrees.

9. The electronic device of claim 6, comprising a user interface configured to receive a user input that enables adjustment of the detected level of ambient light based on the angle of incidence.

10. A method, comprising:

detecting an ambient light level for an ambient light source;

detecting an angle of incidence of the ambient light from the ambient light source;

determining an angular adjustment for the detected ambient light level based on the detected angle of incidence; and

adjusting a brightness of a backlight based on the angular adjustment.

11. The method of claim 10, wherein determining an angular adjustment comprises determining an adjusted ambient light level approximately equal to the detected ambient light level multiplied by the cosine of the detected angle of incidence.

12. The method of claim 10, wherein determining an angular adjustment comprises determining an adjusted ambient light level approximately equal to or greater than the detected ambient light level multiplied by the cosine of the detected angle of incidence and approximately less than the detected ambient light level when the angle of incidence is greater than or less than ninety degrees.

13. The method of claim 10, comprising adjusting the detected ambient light level by the angular adjustment to produce an adjusted ambient light level, wherein adjusting a brightness of the backlight comprises determining a brightness level for the backlight that corresponds to the adjusted ambient light level.

14. The method of claim 10, wherein adjusting a brightness of the backlight comprises determining a brightness level for the backlight that corresponds to the detected ambient light level and applying the angular adjustment to the determined brightness level.

15. The method of claim 10, comprising verifying enablement of an angular adjustment for the backlight.

16. The method of claim 10, comprising:

detecting multiple ambient light levels each corresponding to a different ambient light source;

detecting multiple angles of incidence each corresponding to one of the different ambient light sources; and

weighting the detected ambient light levels based on their corresponding detected angle of incidence.

17. Non-transitory computer-readable storage media comprising instructions for:

adjusting a detected ambient light level to produce an adjusted ambient light level that compensates for the angle of incidence of ambient light; and

adjusting a brightness of a backlight based on the adjusted ambient light level.

18. The non-transitory computer-readable storage media of claim 17, comprising instructions for determining the adjusted ambient light level to be approximately equal to the detected ambient light level multiplied by the cosine of the angle of incidence of ambient light.

19. The non-transitory computer-readable storage media of claim 17, comprising instructions for determining the adjusted ambient light level to be approximately equal to or greater than the detected ambient light level multiplied by the cosine of the angle of incidence of ambient light.

20. An electronic device, comprising:

a display comprising a backlight;

an ambient light sensor configured to detect an ambient light level for one or more ambient light sources each producing an emitted ambient light level measured as ambient light contacting the display at a ninety degree angle of incidence, wherein the detected ambient light level is a function of an actual angle of incidence of each of the one or more ambient light sources with respect to the display; and

a display controller operably coupled to the backlight and configured to adjust a brightness of the backlight based on the detected ambient light level.

21. The electronic device of claim 20, wherein the detected ambient light level is approximately equal to a sum of each of the emitted ambient light levels multiplied by the cosine of each of the actual angles of incidence.

22. The electronic device of claim 20, wherein the detected ambient light level is greater than or approximately equal to a sum of each of the emitted ambient light levels multiplied by the cosine of each of the actual angles of incidence.

23. The electronic device of claim 20, wherein the detected ambient light level is approximately equal to the emitted ambient light level when the actual angle of incidence is approximately ninety degrees.

24. The electronic device of claim 20, wherein the display controller is configured to adjust the brightness using a brightness adjustment profile that identifies brightness levels for the backlight based on the detected ambient light level.