DISPLAY BRIGHTNESS CONTROL BASED ON AMBIENT LIGHT LEVELS

• US 20120019492A1
• 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, Bae, Hopil
• Granted Patent: US 8,884,939 B2
• Time in Patent Office: Days
• 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 the ambient light level. The brightness adjustment profiles may include two or more sections, each corresponding to different ambient light levels, which may be adjusted independently of one another. The different sections may allow a user to customize brightness adjustments for different ambient light conditions. In certain embodiments, the slope and/or offset of a section may be adjusted in response to receiving a user input that changes the brightness setting for a certain ambient light level.

Claims

1. An electronic device, comprising:

a display comprising a backlight;

one or more ambient light sensors configured to detect an ambient light level;

a user interface configured to receive a user input that specifies a reflectivity setting for the backlight; and

a display controller configured to adjust a slope of a brightness adjustment profile for the backlight based on the reflectivity setting, wherein the brightness adjustment profile identifies brightness levels for the backlight based on the ambient light level.

2. The electronic device of claim 1, wherein the user interface is configured to receive another user input that specifies a lamp brightness setting for the backlight, and wherein the display controller is configured to adjust an offset of the brightness adjustment profile for the backlight based on the lamp brightness setting.

3. The electronic device of claim 2, wherein the user interface comprises a first graphical element for receiving the reflectivity setting and a separate second graphical element for receiving the lamp brightness setting.

4. The electronic device of claim 1, wherein the user input specifies a brightness setting for the backlight, and wherein the display controller is configured to adjust an offset of the brightness adjustment profile based on the brightness setting.

5. The electronic device of claim 1, wherein the user interfaces comprises a graphical element manipulatable by a user to specify both the reflectivity setting and the brightness setting.

6. An electronic device, comprising:

a display comprising a backlight;

one or more ambient light sensors configured to detect an ambient light level;

a user interface configured to receive a user input that specifies a brightness setting for the backlight at the detected ambient light level; and

a display controller configured to adjust a slope of at least a section of a brightness adjustment profile for the backlight until the brightness setting and a previously identified transition point on the brightness adjustment profile both intersect the brightness adjustment profile.

7. The electronic device of claim 6, wherein the brightness adjustment profile identifies brightness levels for the backlight based on the ambient light level.

8. The electronic device of claim 6, wherein the previously identified transition point comprises a previously specified brightness setting for the backlight.

9. The electronic device of claim 6, wherein the display controller is configured to adjust the backlight to a brightness level corresponding to the brightness setting.

10. The electronic device of claim 9, wherein the user interface is capable of receiving an additional user input that specifies an adjustment rate for the backlight, and wherein the display controller is configured to adjust the backlight to the brightness level at the specified adjustment rate.

11. The electronic device of claim 6, wherein the display controller is configured to select the section from a first portion of the brightness adjustment profile that specifies first brightness levels for a first range of ambient light levels and a second portion of the brightness adjustment profile that specifies second brightness levels for a second range of ambient light levels different from the first range.

12. The electronic device of claim 11, wherein the display controller is configured to modify the first and second portions independently of one another.

13. A method, comprising:

receiving a user input that identifies a brightness setting for a backlight;

detecting an ambient light level in response to receiving the user input;

determining a section of a brightness adjustment profile for a backlight, wherein the section includes the detected ambient light level; and

adjusting a slope of at least the section of the brightness adjustment profile to produce a modified brightness adjustment profile that intersects the brightness setting or a threshold value at the detected ambient light level and that intersects a previously specified brightness level on the brightness adjustment profile.

14. The method of claim 13, wherein determining a section of a brightness adjustment profile comprises determining whether the detected ambient light level is above or below an ambient light threshold.

15. The method of claim 13, comprising selecting the previously specified brightness level from a plurality of previously specified brightness levels, wherein the previously specified brightness level is on an opposite side of the ambient light threshold from the detected ambient light level.

16. The method of claim 13, comprising determining whether the brightness setting exceeds the threshold value, wherein adjusting the slope of the section of the brightness adjustment profile comprises adjusting the slope until the brightness adjustment profile intersects the threshold value if the brightness setting exceeds the threshold level and adjusting the slope until the brightness adjustment profile intersects the brightness setting if the brightness setting does not exceed the threshold value.

17. The method of claim 13, comprising determining whether the brightness setting exceeds the threshold value, wherein adjusting the slope comprises setting the slope to zero if the brightness setting exceeds the threshold value.

18. The method of claim 13, comprising adjusting a brightness of the backlight based on the modified adjustment profile.

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

determining a section of a brightness adjustment profile for a backlight based on an ambient light level detected upon receipt of a new brightness setting for the backlight, wherein the section includes the detected ambient light level;

selecting a transition point on the brightness adjustment profile, wherein the transition point is on an opposite side of an ambient light threshold from the detected ambient light level; and

adjusting a slope of at least the section of the brightness adjustment profile to produce a modified brightness adjustment profile that intersects the new brightness setting and the transition point.

20. The non-transitory computer-readable storage media of claim 19, comprising instructions for determining that a portion of the modified adjustment profile is above a maximum brightness level or below a minimum brightness level and clipping the portion of the modified adjustment profile to approach or equal the maximum brightness level or the minimum brightness level.

21. The non-transitory computer-readable storage media of claim 19, comprising instructions for determining that the adjusted slope is greater than a maximum slope or less than a minimum slope and modifying the adjusted slope to equal the maximum slope or the minimum slope.

22. A method comprising:

receiving a user input that identifies a brightness setting for a backlight;

detecting an ambient light level in response to receiving the user input;

determining a transition point on the brightness adjustment profile, wherein the transition point is on an opposite side of an ambient light threshold from the detected ambient light level; and

adjusting a slope of the brightness adjustment profile to produce a modified brightness adjustment profile that intersects the brightness setting and the transition point.

23. The method of claim 22, wherein adjusting a slope of the brightness adjustment profile comprises adjusting the slope for a section of the brightness profile that includes the detected ambient light level.

24. The method of claim 22, comprising

determining that the adjusted slope is greater than a maximum slope or less than a minimum slope;

and

setting the slope of the brightness adjustment profile to the maximum slope or the minimum slope.

25. The method of claim 24, wherein setting the slope of the brightness adjustment profile to the maximum slope or the minimum slope comprises adjusting a brightness level for the transition point to produce the maximum slope or the minimum slope.