Camera illumination

• US 10,397,490 B2
• Filed: 02/05/2019
• Issued: 08/27/2019
• Est. Priority Date: 05/27/2015
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Google LLC (Alphabet Inc.)
• Inventors: Dorai, Arvind, Nelson, Anders, Conner, Brian Jonathan
• Primary Examiner(s): Pasiewicz, Daniel M
• Application Number:
  US16/268,396
• Publication Number:
  US 20190174048A1
• Time in Patent Office: 203 Days
• Field of Search: 348370-371
• CPC Class Codes: G03B 15/05 Combinations of cameras with electronic flash apparatus; Electronic flash units
• CPC Class Codes: H04N 23/20 for generating image signals from infrared radiation only
• CPC Class Codes: H04N 23/56 provided with illuminating means
• CPC Class Codes: H04N 23/667 Camera operation mode switching, e.g. between still and video, sport and normal or high- and low-resolution modes
• CPC Class Codes: H04N 23/74 by influencing the scene brightness using illuminating means
• CPC Class Codes: H04N 5/33 Transforming infrared radiation cameras or camera modules for generating image signals from infrared radiation H04N23/20; circuitry of SSIS for transforming infrared radiation into image signals H04N25/20
• CPC Class Codes: H05B 45/10 Controlling the intensity of the light
• CPC Class Codes: H05B 45/38 using boost topology
• CPC Class Codes: H05B 45/385 using flyback topology
• CPC Class Codes: H05B 45/39 Circuits containing inverter bridges
• CPC Class Codes: H05B 45/48 having LEDs organised in strings and incorporating parallel shunting devices

Abstract

This application discloses an electronic device (e.g., a camera) that operates at two distinct modes and includes a camera lens configured to capture visual data of a field of view, a plurality of light sources, and a light source driver. The light sources are configurable to a plurality of light source subsets to illuminate the field of view. At least two of the light source subsets include distinct light source members and are configured to illuminate different regions of the field of view. The light source driver is configured to drive the light sources with two distinct drive voltages at two distinct modes. In a first mode, the light sources are electrically coupled to each other and driven by a first drive voltage. In the second mode, one of the light source subsets is selected and driven by a second drive voltage that is lower than the first dive voltage.

Claims

1. A camera, comprising:

a camera lens configured to capture visual data of a field of view;

a plurality of light sources configured to illuminate the field of view; and

a light source driver coupled to the plurality of light sources and configured to drive the plurality of light sources with a first drive voltage at a first mode and with a second drive voltage at a second mode, the second drive voltage being lower than the first drive voltage;

wherein;

the plurality of light sources is configurable to a plurality of light source subsets;

at least two of the plurality of light source subsets include distinct light source members and are configured to illuminate different regions of the field of view of the camera;

in the first mode, the plurality of light sources are electrically coupled to each other and driven by the first drive voltage; and

in the second mode, one of the plurality of light source subsets is selected and driven by the second drive voltage.

2. The camera of claim 1, wherein in the first mode, the plurality of light sources is electrically coupled in series to form a string that is driven by the first drive voltage.

3. The camera of claim 1, wherein each of the plurality of light source subsets includes one or more light source members, further comprising:

a bypass circuit coupled to the plurality of light sources and configured to enable each of the plurality of light source subsets by bypassing a respective set of light sources that are distinct from the respective one or more light source members of the respective light source subset, allowing the respective one or more light source members to be electrically coupled in series and form the respective light source subset.

4. The camera of claim 3, wherein the bypass circuit includes a plurality of bypass elements, and each light source is coupled in parallel with one of the plurality of bypass elements configurable to bypass the respective light source in the second mode.

5. The camera of claim 1, wherein the plurality of light sources includes eight light sources, and in the second mode, six of the eight light sources are bypassed, and two remaining light sources are coupled in series and driven by the regular drive voltage.

6. The camera of claim 1, wherein the plurality of light sources includes a plurality of light emitting diodes (LEDs).

7. The camera of claim 6, wherein the plurality of LEDs is disposed to surround the camera lens.

8. The camera of claim 7, wherein each LED is tilted with an angle with respect to an optical axis of the camera lens.

9. The camera of claim 8, wherein each LED is tilted away from the optical axis of the camera with the angle in the range of 20-40 degrees.

10. The camera of claim 1, wherein the plurality of light sources is disposed symmetrically with respect to the camera lens.

11. An electronic device, comprising:

a camera lens configured to capture visual data of a field of view;

a plurality of light sources configured to illuminate the field of view; and

a light source driver coupled to the plurality of light sources and configured to drive the plurality of light sources with a first drive voltage at a first mode and with a second drive voltage at a second mode, the second drive voltage being lower than the first drive voltage;

wherein;

the plurality of light sources is configurable to a plurality of light source subsets;

at least two of the plurality of light source subsets include distinct light source members and are configured to illuminate different regions of the field of view of the camera lens;

in the first mode, the plurality of light sources is electrically coupled to each other and driven by the first drive voltage; and

in the second mode, one of the plurality of light source subsets is selected and driven by the second drive voltage.

12. The electronic device of claim 11, further comprising:

a microcontroller configured to control selection of one of the plurality of light source subsets.

13. The electronic device of claim 11, wherein the plurality of light sources includes a plurality of infrared LEDs.

14. The electronic device of claim 13, further comprising:

a dark-colored infrared-transparent cover enclosing the plurality of infrared LEDs, wherein the plurality of infrared LEDs is not visible from an exterior of the electronic device.

15. The camera of claim 13, wherein in a night mode associated with the second mode, one or more of the plurality of infrared light sources is driven to illuminate at least part of the field of view with infrared light.

16. A method of providing a camera, comprising:

providing a camera lens configured to capture visual data of a field of view;

providing a plurality of light sources configured to illuminate the field of view; and

coupling a light source driver to the plurality of light sources, the light source driver being configured to drive the plurality of light sources with a first drive voltage at a first mode and with a second drive voltage at a second mode, the second drive voltage being lower than the first drive voltage;

wherein;

the plurality of light sources is configurable to a plurality of light source subsets;

at least two of the plurality of light source subsets include distinct light source members and are configured to illuminate different regions of the field of view of the camera;

in the first mode, the plurality of light sources is electrically coupled to each other and driven by the first drive voltage; and

in the second mode, one of the plurality of light source subsets is selected and driven by the second drive voltage.

17. The method of claim 16, further comprising:

providing image sensors, a microphone, a speaker, and one or more antennas, wherein the camera is configured to communicate the visual data to a client device via a remote surveillance server in real time while capturing the visual data.

18. The method of claim 16, wherein the plurality of light sources is grouped into four subsets of light sources that are configured to illuminate four quadrants of the field of view, respectively.

19. The method of claim 18, wherein depth information of the field of view is recovered at night time according to the variation of the field of view illuminated by the four subsets of light sources.

20. The method of claim 16, wherein:

when driven by the first drive voltage in the first mode, the plurality of light sources is associated with a first drive current; and

when driven by the second drive voltage in the second mode, the selected one of the plurality of light source subsets is associated with a second drive current that is distinct from the first drive voltage.