Proximity detection apparatus and associated methods having single photon avalanche diodes for determining a quality metric based upon the number of events

Patent metadata

Field	Value
Publication number	US-9316735-B2
Application number	US-201314100781-A
Country	US
Kind code	B2
Filing date	Dec 9, 2013
Priority date	Nov 30, 2010
Publication date	Apr 19, 2016
Grant date	Apr 19, 2016

Abstract

A proximity detector may include an array of single photon avalanche diodes (SPADs) and an illumination source. Illumination from the illumination source may be reflected by a target to the array of single photon avalanche diodes. The SPADs may be operable to detect events. A number of events detected may be dependent on a level of illumination incident on the SPADs. The proximity detector may then determine a quality metric and calculate an output when the quality metric is at a predetermined level. A related method may include regulating the quality of the data on which such a proximity detector apparatus calculates its output.

First claim

That which is claimed:

1. A proximity detection apparatus comprising:
an illumination source;
an array of single photon avalanche diodes (SPADs) configured so that illumination from said illumination source is reflected by a target to said array of SPADs; and
circuitry coupled to said array of SPADs and configured to
determine a number of events based upon said array of SPADs,
determine a quality metric based upon the number of events, and
determine an output when the quality metric is at a threshold level.

2. The proximity detection apparatus of claim 1 , wherein the quality metric is based upon a total number of the events detected by said array of SPADs.

3. The proximity detection apparatus of claim 1 , wherein the quality metric is based upon a number of events detected under ambient illumination conditions.

4. The proximity detection apparatus of claim 1 , wherein said circuitry is configured to repeat cycles of a detection phase and a calculation phase; and wherein the quality metric is determined for each detection phase such that a duration of each detection phase is based upon a value of its corresponding quality metric.

5. The proximity detection apparatus of claim 4 , wherein said circuitry is configured to be in a low power mode where the detection phases are at intervals in a threshold range.

6. The proximity detection apparatus of claim 1 , wherein said array of SPADs are arranged in rows and columns.

7. The proximity detection apparatus of claim 1 , wherein said circuitry comprises a multiplexer and a counter coupled to said array of SPADs and configured to enable measurement of the reflected illumination.

8. The proximity detection apparatus of claim 1 , wherein said circuitry is configured to calculate the output using a range equation based upon a phase difference between the illumination provided and the reflected illumination.

9. The proximity detection apparatus of claim 8 , wherein said circuitry is configured to determine the phase difference by dividing time into two equal duration intervals which alternate repeatedly, the duration of each interval being based upon a modulation frequency of the illumination source, the phase difference being based upon an interval in which the events were detected.

10. A proximity detection apparatus comprising:
an array of single photon avalanche diodes (SPADs) configured so that illumination is reflected by a target to said array of SPADs; and
circuitry coupled to said array of SPADs and configured to
determine a quality metric, and
calculate an output when the quality metric is at a threshold level.

11. The proximity detection apparatus of claim 10 , wherein the quality metric is based upon a total number of events detected by said array of SPADs.

12. The proximity detection apparatus of claim 10 , wherein the quality metric is based upon a number of events detected under ambient illumination conditions.

13. The proximity detection apparatus of claim 10 , wherein said circuitry is configured to repeat cycles of a detection phase and a calculation phase; and wherein the quality metric is determined for each detection phase such that a duration of each detection phase is based upon a value of its corresponding quality metric.

14. A method of regulating a quality of data output by a proximity detector comprising an array of single photon avalanche diodes (SPADs), the method comprising:
turning on an illumination source so that illumination from the illumination source is reflected by a target to the array of SPADs;
counting a number of events detected by the array of SPADs;
determining a quality metric based upon the number of events counted; and
calculating an output, when the quality metric is at a threshold level, and based upon the number of events counted.

15. The method of claim 14 , wherein the quality metric is based upon a total number of events detected by the array of SPADs.

16. The method of claim 14 , wherein the quality metric is based upon a number of events detected under ambient illumination conditions.

17. The method of claim 14 , further comprising repeating cycles of a detection phase and a calculation phase, wherein the quality metric is determined for each detection phase such that a duration of each detection phase is based upon a value of its corresponding quality metric.

18. The method of claim 17 , wherein the detection phases are at intervals in a threshold range.

19. The method of claim 14 , wherein the output is calculated using a range equation based upon a phase difference between the illumination from the illumination source and reflected illumination.

20. A non-transitory computer readable medium for use with a proximity detection apparatus comprising an array of single photon avalanche diodes (SPADs), and having computer-executable instructions for causing the proximity detection apparatus to perform steps comprising:
turning on an illumination source so that illumination from the illumination source is reflected by a target to the array of SPADs;
counting a number of events detected by the array of SPADs;
determining a quality metric based upon the number of events counted; and
calculating an output, when the quality metric is at a threshold level, and based upon the number of events counted.

21. The non-transitory computer-readable medium of claim 20 , wherein the quality metric is based upon a total number of events detected by the array of SPADs.

22. The non-transitory computer-readable medium of claim 20 , wherein the quality metric is based upon a number of events detected under ambient illumination conditions.

23. The non-transitory computer-readable medium of claim 20 , wherein the computer-executable instructions are for repeating cycles of a detection phase and a calculation phase, wherein the quality metric is determined for each detection phase such that a duration of each detection phase is based upon a value of its corresponding quality metric.

24. The non-transitory computer-readable medium of claim 23 , wherein the detection phases are at intervals in a threshold range.

25. The non-transitory computer-readable medium of claim 20 , wherein the output is calculated using a range equation based upon a phase difference between the illumination from the illumination source and reflected illumination.

Assignees

• St Microelectronics Res & Dev

Inventors

• Baxter David Patrick

Classifications

• G01S17/04 Primary

  Systems determining the presence of a target · CPC title

• G01S17/06 Primary

  Systems determining position data of a target · CPC title

• H10F77/953 Primary

  for devices having potential barriers · CPC title

• H10F30/225

  the potential barrier working in avalanche mode, e.g. avalanche photodiodes · CPC title

• H01L31/107

  Electricity · mapped topic