Ambient light sensing technique

• US 9,355,588 B2
• Filed: 10/13/2014
• Issued: 05/31/2016
• Est. Priority Date: 09/01/2010
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Mahowald, Peter H., Barnhoefer, Ulrich T.
• Primary Examiner(s): Johnson, Gerald
• Application Number:
  US14/512,879
• Publication Number:
  US 20150029168A1
• Time in Patent Office: 596 Days
• US Class Current: 1/1
• CPC Class Codes: G09G 2320/0242 Compensation of deficiencies in the appearance of colours
• 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 2320/0666 for control of colour parameters, e.g. colour temperature
• 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 3/3413 Details of control of colour illumination sources
• CPC Class Codes: H04N 13/128 Adjusting depth or disparity
• CPC Class Codes: H05B 47/11 by determining the brightness or colour temperature of ambient light
• CPC Class Codes: Y02B 20/40 Control techniques providing energy savings, e.g. smart controller or presence detection

Abstract

A method for controlling characteristics of an electronic device based on ambient light levels is provided. In one embodiment, the method includes receiving light at an ambient light sensor of a device and measuring components, such as color components, of the visible light. The component levels may be weighted differently by factors that vary based on the intensity of the light received by the ambient light sensor. Also, the brightness level of a light source in the device or color output of the device may be controlled based on the weighted component levels. Additional methods, systems, and devices relating to control of an electronic device based on sensed ambient light are also disclosed.

Claims

1. A method, comprising:

measuring ambient light levels via an ambient light sensor of an electronic device including a display;

detecting that the measured ambient light levels have decreased from a photopic range to a sub-photopic range;

determining whether to apply dark adaptation compensation to adjust a color output of the display;

gradually adjusting the color output of the display to compensate for a gradual color shift that would otherwise be perceived by a user due to dark adaptation when it is determined to apply dark adaptation compensation; and

maintaining the color output of the display when it is determined not to apply dark adaptation compensation.

2. The method of claim 1, wherein detecting that the measured ambient light levels have decreased from a photopic range to a sub-photopic range includes detecting that the measured ambient light levels have decreased by at least half over a time period of less than one minute.

3. The method of claim 1, wherein detecting that the measured ambient light levels have decreased from a photopic range to a sub-photopic range includes detecting that the measured ambient light levels have decreased by at least ninety percent over a time period of less than ten seconds.

4. The method of claim 1, wherein detecting that the measured ambient light levels have decreased from a photopic range to a sub-photopic range includes detecting that the measured ambient light levels have decreased from a photopic range to a scotopic range.

5. The method of claim 1, wherein gradually adjusting the color output of the display to compensate for the gradual color shift that would otherwise be perceived by the user due to dark adaptation includes gradually adjusting the color output over a time period determined by the electronic device based on the magnitude of the decrease in the ambient light levels.

6. The method of claim 5, wherein gradually adjusting the color output of the display to compensate for the gradual color shift that would otherwise be perceived by the user due to dark adaptation includes gradually adjusting the color output over the time period, and the time period is determined by the electronic device also based on an amount of time that the ambient light levels had been in the photopic range before decreasing to the sub-photopic range.

7. The method of claim 1, comprising:

detecting that the measured ambient light levels have increased from the sub-photopic range to the photopic range; and

gradually adjusting the color output of the display to compensate for an additional gradual color shift that would otherwise be perceived by the user due to light adaptation.

8. A system, comprising:

a display panel;

an ambient light sensor configured to receive ambient light; and

a processor configured to provide image data to be displayed by the display panel, wherein the processor is configured to provide adjusted image data as the image data based on a type of the received ambient light when the ambient light indicates the presence of a particular lighting condition.

9. The system of claim 8, wherein the processor is configured to determine a characteristic of the ambient light when the ambient light indicates the presence of the particular lighting condition.

10. The system of claim 9, wherein the processor is configured to determine an ambient light luminance level as the characteristic.

11. The system of claim 9, wherein the processor is configured to determine an ambient light color content as the characteristic.

12. The system of claim 9, wherein the processor is configured to select an ambient light compensation parameter based on the characteristic of the ambient light.

13. The system of claim 12, wherein the processor is configured to adjust the image data utilizing the ambient light compensation parameter to generate the adjusted image data.

14. The system of claim 13, wherein the processor is configured to adjust at least one of a red color component of the image data, a blue color component of the image data, or a green color component of the image data to generate the adjusted image data.

15. The system of claim 8, wherein the processor is configured to provide the adjusted image data as the image data based on whether the type of received ambient light is fluorescent lighting, incandescent lighting, or lighting of predominantly one color as the type of the received ambient light.

16. A device, comprising:

an ambient light sensor configured to receive light; and

a processor configured to;

measure intensity levels of different components of the received light;

generating a first set of weighted measured intensity levels of the different components using the measured intensity levels and a first set of weighting factors;

calculate a first luminance value related to the first set of weighted measured intensity levels; and

control the brightness level of a light source based on the first luminance value when the first luminance is above an upper threshold value.

17. The device of claim 16, wherein the first set of weighting factors is associated with a photopic luminance range.

18. The device of claim 17, wherein the processor is configured to measure the intensity levels of the different components of the received light by measuring the intensity levels of different color components of the received light, and generate the first set of weighted measured intensity levels of the different components by generating the first set of weighted measured intensity levels of the different color components.

19. The device of claim 18, wherein the different color components include red, green, and blue color components, wherein the first set of weighting factors comprise a first set of red, green, and blue weighting factors associated with the photopic luminance range.

20. The device of claim 16, wherein the processor is configured to:

generate a second set of weighted measured intensity levels of the different components using the measured intensity levels and a second set of weighting factors when the first luminance value is below a lower threshold value;

calculate a second luminance of the second set of weighted measured intensity levels; and

control the brightness level of the light source based on the second luminance when the first luminance is below the lower threshold value.

21. The device of claim 20, wherein the processor is configured to:

generate a third set of weighted measured intensity levels of the different components using the measured intensity levels and a third set of weighting factors when the first luminance value is equal to or exceeds the lower threshold value and does not exceed the upper threshold;

calculate a third luminance of the third set of weighted measured intensity levels; and

control the brightness level of the light source based on the third luminance when the first luminance is equal to or exceeds the lower threshold value and does not exceed the upper threshold.