Luminescence shock avoidance in display devices

• US 9,858,896 B2
• Filed: 09/07/2016
• Issued: 01/02/2018
• Est. Priority Date: 01/05/2007
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Pantfoerder, Kai Achim
• Primary Examiner(s): Caschera, Antonio A
• Application Number:
  US15/258,937
• Publication Number:
  US 20160379596A1
• Time in Patent Office: 482 Days
• CPC Class Codes: G06F 3/0416 Control or interface arrangements specially adapted for digitisers
• CPC Class Codes: G09G 2320/0606 Manual adjustment
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2320/0633 by amplitude modulation of the brightness of the illumination source
• CPC Class Codes: G09G 2320/0653 Controlling or limiting the speed of brightness adjustment of the illumination source
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 2360/144 the light being ambient light
• CPC Class Codes: G09G 3/20 for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
• CPC Class Codes: G09G 3/2003 Display of colours specific for liquid crystal displays G09G3/3607
• CPC Class Codes: G09G 5/10 Intensity circuits

Abstract

A luminescence shock avoidance algorithm selectively limits the brightness level of a display device when the display device is activated in a dark environment to prevent the temporary vision impairment that can occur when a display device is activated in a dark environment. The algorithm receives the state of the display (e.g. on or in standby mode), and can optionally receive an ambient lighting value from an ambient light sensor and a user-selectable manual brightness adjustment setting to determine whether luminescence shock avoidance should even be triggered, and if it is triggered, how much should the brightness level of the display be limited.

Claims

1. A method for operating an electronic device, the method comprising:

detecting a triggering activity;

in response to detecting the triggering activity, activating an ambient light sensor in the electronic device;

detecting an ambient light level with the ambient light sensor;

comparing the detected ambient light level to a threshold value; and

with processing circuitry in the electronic device, activating a display having display settings that determine one of a first brightness function and a second brightness function to be used to adjust display brightness, activating the display comprising;

when the display settings determine that the first brightness function is to be used, activating the display in the electronic device based on the comparison between the detected ambient light level and the threshold value by limiting an initial display brightness to a first initial display brightness level based on the detected ambient light level, the first initial brightness level determined by a first reduced brightness function; and

when the display settings determine that the second brightness function is to be used, activating the display in the electronic device based on the comparison between the detected ambient light level and the threshold value by limiting the initial brightness of the display to a second initial brightness level based on the detected ambient light level, the second initial brightness level determined by a second reduced brightness function that is different than the first reduced brightness function.

2. The method defined in claim 1, wherein the first reduced brightness function has a first slope and the second reduced brightness function has a second slope, and wherein the first slope is greater than the second slope.

3. The method defined in claim 2, wherein the first brightness function has a third slope, and the second brightness function has a fourth slope that is equal to the third slope.

4. The method defined in claim 3, wherein the first slope is greater than the third slope.

5. The method defined in claim 3, wherein the second slope is greater than the fourth slope.

6. The method defined in claim 1, wherein limiting the initial display brightness to the first initial display brightness level based on the detected ambient light level comprises limiting the initial display brightness to the first initial display brightness level when the detected ambient light level is below a threshold.

7. The method defined in claim 6, wherein limiting the initial display brightness to the second initial display brightness level based on the detected ambient light level comprises limiting the initial display brightness to the second initial display brightness level when the detected ambient light level is below the threshold.

8. A method for operating an electronic device, the method comprising:

with a sensor in the electronic device, determining an ambient light level; and

with processing circuitry in the electronic device, activating a display in the electronic device, wherein the display is configured to use at least first and second brightness functions to determine normal display brightness based on the ambient light level, activating the display comprising;

with the processing circuitry, determining whether the ambient light level is below a threshold;

in response to determining that the ambient light level is below the threshold when the display is configured to use the first brightness function to determine the normal display brightness, using a first reduced brightness function to set an initial brightness of the display to a first reduced brightness level based on the ambient light level; and

in response to determining that the ambient light level is below the threshold when the display is configured to use the second brightness function to determine the normal display brightness, using a second reduced brightness function to set an initial brightness of the display to a second reduced brightness level based on the ambient light level.

9. The method defined in claim 8, further comprising:

after a predetermined amount of time at the first reduced brightness level, increasing the brightness of the display from the first reduced brightness level to the normal display brightness.

10. The method defined in claim 8, wherein the normal display brightness determined by the first brightness function for a given ambient light level is greater than the normal display brightness determined by the second brightness function for the given ambient light level.

11. The method defined in claim 10, wherein the first reduced brightness level determined by the first reduced brightness function for the given ambient light level is greater than the second reduced display brightness level determined by the second reduced brightness function for the given ambient light level.

12. The method defined in claim 11, wherein the first and second reduced brightness functions have first and second respective slopes, and wherein the first slope is greater than the second slope.

13. The method defined in claim 12, wherein the sensor is an ambient light sensor.

14. The method defined in claim 8, wherein at least one of the first and second brightness functions is non-linear.

15. An electronic device, comprising:

a sensor that determines an ambient light level;

a display that is configured to use at least first and second brightness functions to determine a normal display brightness level based on the ambient light level; and

processing circuitry that determines whether the ambient light level is below a threshold, wherein the processing circuitry uses a first reduced brightness function to set an initial brightness of the display to a first reduced brightness level based on the ambient light level when the display is configured to use the first brightness function to determine the normal display brightness level and the ambient light level is below the threshold, and wherein the processing circuitry uses a second reduced brightness function to set the initial brightness of the display to a second reduced brightness level based on the ambient light level when the display is configured to use the second brightness function to determine the normal display brightness level and the ambient light level is below the threshold.

16. The electronic device defined in claim 15 wherein the processing circuitry increases the brightness of the display from the first reduced brightness level to the normal display brightness after a predetermined amount of time at the first reduced brightness level.

17. The electronic device defined in claim 15, wherein the normal display brightness level determined by the first brightness function for a given ambient light level is greater than the normal display brightness determined by the second brightness function for the given ambient light level.

18. The electronic device defined in claim 17, wherein the first reduced brightness level determined by the first reduced brightness function for the given ambient light level is greater than the second reduced display brightness level determined by the second reduced brightness function for the given ambient light level.

19. The electronic device defined in claim 18, wherein the first and second reduced brightness functions have first and second respective slopes, and wherein the first slope is greater than the second slope.

20. The electronic device defined in claim 15, wherein the sensor is an ambient light sensor.