OPTICAL MEASURING SENSOR

• US 20130155396A1
• Filed: 12/19/2011
• Published: 06/20/2013
• Est. Priority Date: 12/19/2011
• Status: Active Grant

• Current Assignee: Analog Devices, Inc.
• Original Assignee: Analog Devices, Inc.
• Inventors: Deliwala, Shrenik
• Granted Patent: US 9,702,690 B2
• Time in Patent Office: Days
• US Class Current: 356/138
• CPC Class Codes: G01B 11/14 for measuring distance or clearance between spaced objects or spaced apertures G01B11/26 takes precedence; rangefinders G01C3/00
• CPC Class Codes: G01B 11/26 for measuring angles or tapers; for testing the alignment of axes
• CPC Class Codes: G01J 1/0242 Control or determination of height or angle information of sensors or receivers; Goniophotometry
• CPC Class Codes: G01J 1/0437 using masks, aperture plates, spatial light modulators, spatial filters, e.g. reflective filters
• CPC Class Codes: G01J 1/1626 Arrangements with two photodetectors, the signals of which are compared

Abstract

An optical detector may include an aperture, at least two photodetectors, and a measuring arrangement to quantify light detected at the photodetectors after passing through the aperture without the need for a lens. The aperture may be positioned between a light source and the two photodetectors to allow light from a light source to pass through the aperture to the photodetectors. The photodetectors may include PIN junction photodiodes and may be electrically isolated from each other, positioned next to each other in a side-by-side configuration, and then aligned with the aperture so that a proportion of the quantified light detected at the photodetectors changes as an angle of light from the light source incident to the aperture changes. Optical detectors and methods are provided.

Claims

1. An optical detector integrated circuit comprising:

a surface having an aperture; and

a pair of photodetectors isolated from each other at a boundary between them, the boundary aligned with the aperture.

2. The optical detector integrated circuit of claim 1, wherein the boundary is aligned with the aperture when a center of the boundary is centered with a center of the aperture.

3. The optical detector integrated circuit of claim 1, wherein the boundary is aligned with the aperture when a center of the boundary is offset from a center of the aperture.

4. The optical detector integrated circuit of claim 1, wherein the aperture is a slit.

5. The optical detector integrated circuit of claim 1, wherein each edge of the aperture is beveled.

6. The optical detector integrated circuit of claim 5, wherein the beveled edges of the aperture are directed away from the photodetectors.

7. The optical detector integrated circuit of claim 1, wherein the aperture is a section of the surface permeable to light.

8. The optical detector integrated circuit of claim 1, wherein the surface having the aperture is positioned at a height less than 30 microns above the pair of photodetectors.

9. The optical detector integrated circuit of claim 1, wherein the surface having the aperture is positioned at a height less than 10 microns above the pair of photodetectors.

10. The optical detector integrated circuit of claim 1, wherein the surface having the aperture is positioned directly on top of the pair of photodetectors.

11. The optical detector integrated circuit of claim 4, wherein the surface has a plurality of slit apertures;

and further comprising a pair of photodetectors for each of the plurality of slit apertures, the photodetectors in each pair isolated from each other at a boundary between them aligned with the corresponding slit aperture.

12. The optical detector integrated circuit of claim 11, wherein the boundaries of each of the photodetector pairs are offset by different amounts from their corresponding apertures as part of the alignment.

13. The optical detector integrated circuit of claim 11, wherein at least two of the slit apertures and their corresponding photodetector pairs are arranged perpendicular to each other in the optical detector.

14. The optical detector integrated circuit of claim 13, wherein at least two of the slit apertures and their corresponding photodetector pairs are arranged parallel to each other in the optical detector.

15. The optical detector integrated circuit of claim 13, wherein at least two of the slit apertures and their corresponding photodetector pairs are arranged at either acute or obtuse angles to each other in the optical detector.

16. The optical detector integrated circuit of claim 13, wherein the photodetectors in at least one of the photodetector pairs are located in different planes in the optical detector.

17. An optical detector comprising:

a surface having an aperture;

a plurality of photodetectors; and

a measuring arrangement, wherein the measuring arrangement calculates an angle of incident light from a proportion of the incident light detected at at least two of the photodetectors after passing through the aperture.

18. The optical detector of claim 17, wherein the aperture is a section of the surface of the integrated circuit permeable to light.

19. The optical detector of claim 17, wherein the measuring arrangement uses photocurrents to quantify the proportion of the incident light detected.

20. The optical detector of claim 17, wherein the measuring arrangement uses photodetector initiated changes to a resistance or conductivity parameter of a circuit to quantify the proportion of the incident light detected.

21. The optical detector of claim 17, further comprising an electrical isolator to electrically isolate the photodetectors.

22. The optical detectors of claim 21, wherein the electrical isolator is a trench.

23. The optical detector of claim 17, wherein the plurality of photodetectors comprise PIN junction photodiodes.

24. The optical detector of claim 17, further comprising:

a plurality of slit apertures; and

a pair of electrically isolated photodetectors arranged side-by-side for each of the plurality of slit apertures to detect a change to light passing through its respective slit aperture as the angle of light incident to its respective slit aperture changes.

25. The optical detector of claim 24, wherein outputs of corresponding photodetectors in each of the photodetector pairs are coupled together to increase light collection efficiency.

26. The optical detector of claim 24, wherein each of the slit apertures have beveled edges pointing away from the photodetectors.

27. The optical detector of claim 24, wherein a center of at least one pair of the electrically isolated photodetectors arranged side-by-side is aligned with a center of its corresponding slit aperture.

28. The optical detector of claim 24, wherein a center of at least one pair of the electrically isolated photodetectors arranged side-by-side is offset from a center of its corresponding slit aperture.

29. The optical detector of claim 17, further comprising a medium between the aperture and the plurality of photodetectors that does not focus light passing through it.

30. The optical detector of claim 29, wherein the medium is a glass or a polymer.

31. The optical detector of claim 17, wherein:

the optical detector is included in a remote control;

the remote control controls an instrument having a modulated light source;

the photodetectors in the optical detector are configured to detect modulated light from the modulated light source; and

the measuring arrangement calculates a position of either (i) the optical detector with respect to the modulated light source or (ii) the remote control with respect to the instrument.

32. The optical detector of claim 17, wherein:

the optical detector is included in an instrument controlled by a remote control;

the remote control includes a modulated light source;

the photodetectors in the optical detector are configured to detect modulated light from the modulated light source; and

the measuring arrangement calculates a position of either (i) the optical detector with respect to the modulated light source or (ii) the remote control with respect to the instrument.

33. The optical detector of claim 17, wherein:

the optical detector is included in a component of a vehicle; and

the measuring arrangement calculates a position of an object with respect to the optical detector based on a calculated angle of light reflected off the object and detected at the photodetectors.

34. The optical detector of claim 17, wherein photocurrents generated from light of at least two wavelengths detected at the photodetectors is used to generate a photoplethysmograph.

35. A method comprising:

identifying a proportion of incident light detected at a plurality of photodetectors after passing through an aperture; and

calculating positional information of the incident light from the identified proportion of incident light detected at the plurality of photodetectors.

36. The method of claim 35, wherein the calculated positional information includes an angle of the incident light.

37. The method of claim 35, wherein the calculated positional information includes a plurality of angles of the incident light in a plurality of dimensions.

38. The method of claim 37, wherein the calculated positional information includes a directional change of the incident light based on a change in at least one of angles.

39. The method of claim 35, wherein the incident light is not focused after passing through the aperture.

40. The method of claim 35, wherein the incident light is not focused as it passes through the aperture.

41. The method of claim 35, wherein the incident light passes through a medium between the aperture and the plurality of photodetectors before reaching the plurality of photodetectors.

42. The method of claim 41, wherein the medium does not focus light passing through it.

43. The method of claim 42, wherein the medium is a glass or a polymer.