Display brightness control based on ambient light angles

• US 8,686,981 B2
• Filed: 09/30/2010
• Issued: 04/01/2014
• Est. Priority Date: 07/26/2010
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Barnhoefer, Ulrich T., Chen, Wei
• Primary Examiner(s): A, Minh D
• Application Number:
  US12/895,260
• Publication Number:
  US 20120019152A1
• Time in Patent Office: 1,279 Days
• Field of Search: 315149-159, 315/291, 315/307, 315/308, 345/102, 345/204, 345/205, 345/207, 345690-691, 345696-697, 250/215, 250/227.14, 250/397
• US Class Current: 345/207
• 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 level and an angle of incidence value of ambient light; and

a display controller operably coupled to the backlight and configured to;

determine an angular adjustment profile based upon the angle of incidence value;

wherein the angular adjustment profile defines adjustments to the detected ambient light level based upon the angle of incidence;

determine an adjusted ambient light level by multiplying the ambient light level by the angular adjustment profile; and

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

2. The electronic device of claim 1, wherein the sensing device comprises an ambient light sensor and the display controller is configured to determine the angular adjustment profile as the cosine of the angle of incidence value.

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 a particular angular adjustment profile for the backlight, wherein the particular angular adjustment profile specifies angular-based adjustments to the brightness based on the detected ambient light angle to simulate a reflectivity associated with hard copy material.

5. The electronic device of claim 1, comprising a user interface configured to receive a user input that selectively enables or disables adjustment of the brightness of the backlight based upon the angle of incidence of the ambient light.

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 value of the ambient light; and

a display controller operably coupled to the backlight and configured to;

determine an angular adjustment profile based at least on the level of ambient light and a function of the angle of incidence value, wherein the angular adjustment profile defines adjustments to the detected ambient light level based upon the angle of incidence;

adjust the detected level of ambient light based on the angular adjustment profile to produce an adjusted ambient light level; and

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 selectively enables or disables adjustment of the detected level of ambient light based on the angle of incidence.

10. A method, comprising:

detecting whether an angular adjustment function is selectively enabled via a user selection in a graphical user interface;

when the adjustment function is selectively enabled;

detecting, via a display controller, an ambient light level for an ambient light source;

detecting, via the display controller, an angle of incidence value of the ambient light from the ambient light source;

determining, via the display controller, an angular adjustment profile for the detected ambient light level based on the detected angle of incidence value;

wherein the angular adjustment profile defines adjustments to the detected ambient light level based upon the angle of incidence; and

adjusting, via the display controller, a brightness of a backlight based on the angular adjustment profile.

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;

weighting the different ambient light sources based upon their corresponding detected ambient light levels and their corresponding detected angle of incidence; and

calculating an angular adjustment profile based upon the weighted different ambient light sources;

wherein the angular adjustment profile defines adjustments to the detected ambient light levels based upon the angles of incidence.

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

determining an angular adjustment profile based at least on;

a level of ambient light detected by a sensor and

a function of a value of the angle of incidence of the ambient light detected by the sensor,

adjusting, using the angular adjustment profile, the 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 angular adjustment profile by determining 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; and

a display controller operably coupled to the ambient light sensor and the backlight and configured to;

determine a particular angular adjustment profile for the backlight, wherein the angular adjustment profiles specifies angular-based adjustments to the brightness based on the detected ambient light angle to simulate a reflectivity associated with a hard copy material; and

adjust a brightness of the backlight based on the detected ambient light level based upon the particular angular adjustment profile.

21. The electronic device of claim 20, wherein the display controller is configured to determine the particular angular adjustment profile for the backlight from a selection of a particular hard copy material profile provided in a graphical user interface.

22. The electronic device of claim 20, wherein the particular hard copy material profile comprises a book profile and the particular angular adjustment profile specifies angular-based adjustments to simulate a reflectivity associated with a book.

23. The electronic device of claim 20, wherein the particular hard copy material profile comprises a newspaper profile and the particular angular adjustment profile specifies angular-based adjustments to simulate a reflectivity associated with a newspaper.

24. The electronic device of claim 20, wherein the display controller is configured to:

detect whether an angular adjustment selection is selectively enabled; and

adjust a brightness of the backlight based on the detected ambient light level based upon the particular angular adjustment profile only when the angular adjustment setting is selectively enabled.