Luminescence shock avoidance in display devices

• US 9,443,460 B2
• Filed: 07/07/2015
• Issued: 09/13/2016
• 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:
  US14/793,627
• Publication Number:
  US 20150310795A1
• Time in Patent Office: 434 Days
• US Class Current: 1/1
• 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 of operating an electronic device, the method comprising:

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

with processing circuitry in the electronic device, comparing the detected ambient light level to a threshold; and

with the processing circuitry, activating a display in the electronic device, wherein when the detected ambient light level is less than the threshold, activating the display comprises at least temporarily shifting a color of light emitted by the display.

2. The method defined in claim 1, wherein shifting the color of the light emitted by the display comprises adjusting a first wavelength of light emitted by the display towards a second wavelength corresponding to red light.

3. The method defined in claim 2, wherein the first wavelength of light emitted by the display is selected from the group consisting of:

green light and blue light.

4. The method defined in claim 1, wherein shifting the color of light emitted by the display comprises adjusting input signals provided to the display using gamma-shift logic in the electronic device.

5. The method defined in claim 1, wherein when the detected ambient light level is equal to or greater than the threshold, activating the display comprises activating the display without shifting the color of light emitted by the display.

6. The method defined in claim 1, further comprising:

with the processing circuitry in the electronic device, determining a first brightness level for the display based on the detected ambient light level.

7. The method defined in claim 6, wherein when the detected ambient light level is less than the threshold, activating the display comprises activating the display at a second brightness level that is less than the first brightness level.

8. The method defined in claim 7, wherein when the detected ambient light level is equal to or greater than the threshold, activating the display comprises activating the display at the first brightness level.

9. An electronic device, comprising:

a display that emits light;

a sensor that detects an ambient light level at the electronic device;

processing circuitry that determines whether the detected ambient light level is less than a threshold; and

gamma-shift logic in the processing circuitry that performs a gamma-shift operation to adjust the light emitted by the display when the processing circuitry determines that the detected ambient light level is less than the threshold.

10. The electronic device defined in claim 9, wherein the gamma-shift logic provides input signals to the display and wherein the gamma-shift operation comprises altering the input signals.

11. The electronic device defined in claim 9, wherein the gamma-shift logic adjusts the light emitted by the display by adjusting a first wavelength of light emitted by the display towards a second wavelength corresponding to red light.

12. The electronic device defined in claim 11, wherein the first wavelength of light emitted by the display is selected from the group consisting of:

green light and blue light.

13. The electronic device defined in claim 9, wherein when the detected ambient light level is equal to or greater than the threshold, the gamma-shift logic does not gamma-shift the light emitted by the display.

14. The electronic device defined in claim 9, wherein the processing circuitry determines a first brightness level for the display based on the detected ambient light level.

15. The electronic device defined in claim 14, wherein when the detected ambient light level is less than the threshold, the display emits light at a second brightness level that is less than the first brightness level.

16. The electronic device defined in claim 15, wherein when the detected ambient light level is equal to or greater than the threshold, the display emits light at the first brightness level.

17. A method for operating an electronic device, 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 in the electronic device based on the comparison between the detected ambient light level and the threshold value, wherein activating the display comprises limiting an initial brightness of the display to an initial brightness level that is based on the detected ambient light level.

18. The method defined in claim 17, wherein activating the ambient light sensor comprises turning the ambient light sensor on.

19. The method defined in claim 17, wherein the triggering activity comprises an incoming telephone call.

20. The method defined in claim 17, wherein when the detected ambient light level is less than the threshold value, activating the display comprises gamma-shifting light that is emitted from the display into the red region of the electromagnetic spectrum to avoid luminescence shock.