Device having light intensity measurement in presence of shadows

• US 9,194,741 B2
• Filed: 09/06/2013
• Issued: 11/24/2015
• Est. Priority Date: 09/06/2013
• Status: Active Grant

• Current Assignee: Malikie Innovations Limited (Key Patent Innovations Limited)
• Original Assignee: Blackberry Limited
• Inventors: Carmel-Veilleux, Tennessee
• Primary Examiner(s): LE, QUE TAN
• Application Number:
  US14/019,740
• Publication Number:
  US 20150069921A1
• Time in Patent Office: 809 Days
• Field of Search: 250/205, 250/214.R, 250/214.1, 250/214.VT, 250/208.1, 345 85-117, 362231-276
• US Class Current: 1/1
• CPC Class Codes: G01J 1/4228 arrangements with two or more detectors, e.g. for sensitivity compensation
• CPC Class Codes: G05F 3/262 using field-effect transistors only
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2320/066 for control of contrast
• CPC Class Codes: G09G 2320/0693 Calibration of display systems
• 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 3/00 Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
• 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: H05B 47/10 Controlling the light source
• CPC Class Codes: H05B 47/11 by determining the brightness or colour temperature of ambient light
• CPC Class Codes: H05B 47/19 via wireless transmission
• CPC Class Codes: Y02B 20/40 Control techniques providing energy savings, e.g. smart controller or presence detection

Abstract

A device and method for detecting lighting conditions to enable brightness control of a display are disclosed. The device includes a display and a first photodiode array to detect light in a visible spectrum and a non-visible spectrum that is incident on the first photodiode array. The device also includes a second photodiode array to detect light in the non-visible spectrum that is incident on the second photodiode array, and a processor to determine the lighting conditions based on a first output of the first photodiode array and a second output of the second photodiode array. The processor adjusts the first output used to determine the lighting conditions based on detecting that the first photodiode array includes a shadowed region, and controls the brightness of the display based on the lighting conditions.

Claims

1. An electronic device, comprising:

a display;

a first photodiode array configured to detect light in a visible spectrum and a non-visible spectrum that is incident on the first photodiode array;

a second photodiode array configured to detect light in the non-visible spectrum that is incident on the second photodiode array; and

a processor configured to determine lighting conditions and to control brightness of the display based on a first output of the first photodiode array and a second output of the second photodiode array, the processor adjusting the first output used to determine the lighting conditions based on detecting that the first photodiode array includes a shadowed region.

2. The device according to claim 1, wherein the first output is proportional to the light in the visible spectrum and the non-visible spectrum that is incident on the first photodiode array and the second output is proportional to the light in the non-visible spectrum that is incident on the second photodiode array.

3. The device according to claim 1, wherein the processor determines a difference between the first output and the second output, the difference being based on a subtraction of the second output from the first output.

4. The device according to claim 3, wherein the difference is the subtraction of the second output, multiplied by a second factor, from the first output, multiplied by a first factor, the first factor and the second factor being determined based on a calibration.

5. The device according to claim 3, wherein the processor detects that the first photodiode array includes the shadowed region based on the difference being zero or a negative value.

6. The device according to claim 3, wherein the processor determines an illuminance in lumens per square meter (lux) based on the difference between the first output and the second output and outputs the illuminance as the lighting conditions unless the processor detects that the first photodiode array includes the shadowed region.

7. The device according to claim 6, wherein the processor detects that the first photo diode array includes the shadowed region based on a ratio of the second output to the illuminance exceeding a ratio threshold.

8. The device according to claim 7, wherein the processor detects that the first photodiode array includes the shadowed region based additionally on the second output exceeding an output threshold.

9. The device according to claim 1, wherein the processor adjusts the first output used to determine the lighting conditions to be a ratio of the second output to an artificial ratio, the artificial ratio being determined based on a calibration.

10. A non-transitory computer readable medium storing instructions which, when processed by a processor, cause the processor to execute a method of detecting lighting conditions, the method comprising:

receiving a first output from a first photodiode array that is proportional to light in a visible spectrum and a non-visible spectrum that is incident on the first photodiode array;

receiving a second output from a second photodiode array that is proportional to light in the non-visible spectrum that is incident on the second photodiode array;

determining the lighting conditions based on the first output and the second output; and

adjusting the first output used to determine the lighting conditions based on detecting that the first photodiode array includes a shadowed region.

11. A method of detecting lighting conditions, the method comprising:

detecting, using a first photodiode array, light in a visible spectrum and a non-visible spectrum that is incident on the first photodiode array;

detecting, using a second photodiode array, light in the non-visible spectrum that is incident on the second photodiode array;

determining, using a processor, the lighting conditions based on a first output of the first photodiode array and a second output of the second photodiode array; and

adjusting, using the processor, the first output used to determine the lighting conditions based on detecting that the first photodiode array includes a shadowed region.

12. The method according to claim 11, wherein the first output is proportional to the light in the visible spectrum and the non-visible spectrum that is incident on the first photodiode array and the second output is proportional to the light in the non-visible spectrum that is incident on the second photodiode array.

13. The method according to claim 11, further comprising the processor determining a difference between the first output and the second output, the difference being based on a subtraction of the second output from the first output.

14. The method according to claim 13, wherein the processor determines the difference as the subtraction of the second output, multiplied by a second factor, from the first output, multiplied by a first factor, the first factor and the second factor being determined based on a factor calibration process.

15. The method according to claim 13, further comprising the processor detecting that the first photodiode array includes the shadowed region based on the difference being zero or a negative value.

16. The method according to claim 13, further comprising the processor determining an illuminance in lumens per square meter (lux) based on the difference between the first output and the second output and outputting the illuminance as the lighting conditions unless the processor detects that the first photodiode array includes the shadowed region.

17. The method according to claim 16, further comprising the processor detecting that the first photo diode array includes the shadowed region based on a ratio of the second output to the illuminance exceeding a ratio threshold.

18. The method according to claim 17, further comprising the processor detecting that the first photodiode array includes the shadowed region based additionally on the second output exceeding an output threshold.

19. The method according to claim 11, wherein the processor adjusting the first output includes the processor setting the first output as a ratio of the second output to an artificial ratio.

20. The method according to claim 19, further comprising determining the artificial ratio based on a ratio calibration process.