MULTIUSE OPTICAL SENSOR

• US 20100305418A1
• Filed: 05/20/2010
• Published: 12/02/2010
• Est. Priority Date: 05/27/2009
• Status: Active Grant

• Current Assignee: Analog Devices, Inc.
• Original Assignee: Analog Devices, Inc.
• Inventors: DELIWALA, Shrenik
• Granted Patent: US 9,304,202 B2
• Time in Patent Office: Days
• US Class Current: 600/324
• CPC Class Codes: A61B 5/02108 from analysis of pulse wave characteristics
• CPC Class Codes: A61B 5/022 by applying pressure to close blood vessels, e.g. against the skin; Ophthalmodynamometers
• CPC Class Codes: A61B 5/02427 Details of sensor
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/486 Bio-feedback A61B5/375 takes precedence
• CPC Class Codes: A61B 5/684 Indicating the position of the sensor on the body
• CPC Class Codes: A61B 5/721 using a separate sensor to detect motion or using motion information derived from signals other than the physiological signal to be measured
• CPC Class Codes: G01S 17/06 Systems determining position data of a target
• CPC Class Codes: G01S 17/87 Combinations of systems using electromagnetic waves other than radio waves
• CPC Class Codes: G01S 3/783 using amplitude comparison of signals derived from static detectors or detector systems
• CPC Class Codes: G01S 5/16 using electromagnetic waves other than radio waves

Abstract

One or more electromagnetic radiation sources, such as a light emitting diode, may emit electromagnetic waves into a volume of space. When an object enters the volume of space, the electromagnetic waves may reflect off the object and strike one or more position sensitive detectors after passing through an imaging optical system such as glass, plastic lens, or a pinhole located at known distances from the sources. Mixed signal electronics may process detected signals at the position sensitive detectors to calculate position information as well as total reflected light intensity, which may be used in medical and other applications. A transparent barrier may separate the sources and detectors from the objects entering the volume of space and reflecting emitted waves. Methods and devices are provided.

Claims

1. A device comprising:

a source emitting electromagnetic radiation into a volume of space, the source modulated to reduce an effect of ambient radiation on the measurement;

a position sensitive detector measuring a position of the electromagnetic radiation reflected off an object in the volume of space; and

electronics to calculate a position of the object in the volume of space based on the position of the measured reflected radiation.

2. The device of claim 1, wherein the calculated position of the object updates as the object is moved.

3. The device of claim 1, wherein the electronics further calculates an intensity of the reflected radiation.

4. The device of claim 1, wherein the source and the detector are co-located on a two-dimensional plane.

5. The device of claim 1, wherein the source and the detector are co-located in a device.

6. The device of claim 1, further comprising a transparent barrier between the object and the detector, wherein the reflected radiation travels through the barrier.

7. The device of claim 1, wherein the source and the detector are modulated in a time domain.

8. The device of claim 1, wherein the source is modulated in a frequency domain.

9. The device of claim 6, wherein the source is co-located with the detector on a same side of the barrier.

10. The device of claim 9, wherein the source is configured to emit radiation through the barrier.

11. The device of claim 10, wherein the detector measures the position of the electromagnetic radiation reflected off an object when the object is touching a surface of the barrier and the electronics calculate movement of the object on the surface of the barrier.

12. The device of claim 10, wherein the electronics are able to continuously calculate movement as the object moves between the volume of space and the barrier surface.

13. A device comprising:

a plurality of sources emitting electromagnetic radiation in a plurality of directions through a transparent barrier, some of the radiation entering a volume of space behind a first side of the barrier;

a position sensitive detector behind a second side of the barrier measuring a position and intensity of the electromagnetic radiation reflected off at least one object, the sources modulated to reduce an effect of ambient radiation on the measurement and identify radiation from different sources at the detector; and

electronics to calculate a position of the at least one object based on the position of the measured reflected radiation and distinguish whether the at least one object is located in the volume of space or on the surface of the first side of the barrier based on an intensity comparison of reflected radiation from the plurality of sources.

14. The device of claim 13, wherein the calculated position of the at least one object updates as the at least one object is moved.

15. The device of claim 13, wherein the electronics further calculate a pressure applied to the barrier by the at least one object based on changes to the reflected light intensity.

16. The device of claim 13, wherein the electronics further calculate a photoplethysmograph from changes to the reflected light intensity when the at least one object is a body part of organism.

17. The device of claim 16, wherein the electronics further calculate a heart rate of the organism from the photoplethysmograph.

18. The device of claim 16, wherein each of the sources emits electromagnetic radiation having a unique wavelength.

19. The device of claim 18, wherein the electronics further calculate a measure of oxygenation.

20. The device of claim 13, wherein the electronics are configured to instruct a user where to move the at least one object to improve the reflected light intensity based on the position of the measured reflected radiation.

21. The device of claim 13, wherein the electronics further calculates a distance of the at least one object.

22. The device of claim 13, wherein the electronics calculates the position of a plurality of objects based on the position of the measured reflected radiation off each object and distinguish whether each object is located in the volume of space or on the surface of the first side of the barrier based on an intensity comparison of reflected radiation off each object from the plurality of sources.

23. The device of claim 22, wherein each of the sources emits radiation into a different subset of the volume of space, each of the objects is located in a unique subset of the different subsets, and the calculated position of each object is updated as each object is moved.

34. The device of claim 15, wherein the device is an electronics device.

35. The device of claim 34, wherein the electronics device is a display.

37. The method of claim 34, wherein calculating the position of the object includes updating the position of the object as the object is moved.

24. A device comprising:

a source emitting electromagnetic radiation through a transparent barrier;

a position sensitive detector behind a first side of the barrier measuring a position and intensity of the electromagnetic radiation reflected off a body part of an organism placed on a surface of a second side of the barrier, the source modulated to reduce an effect of ambient radiation on the measurement; and

electronics to calculate a position of the body part on the surface of the barrier based on the position of the measured reflected radiation and a photoplethysmograph from changes to the reflected light intensity.

25. The device of claim 24, wherein the calculated position of the body part updates as the body part is moved.

26. The device of claim 24, wherein the electronics further calculate a heart rate of the organism from the photoplethysmograph.

27. The device of claim 24, further comprising a plurality of sources, each emitting electromagnetic radiation having a unique wavelength, the sources modulated to identify the source of reflected radiation at the detector.

28. The device of claim 27, wherein the wavelength of the radiation from a first source is around 660 nm and the wavelength of the radiation from a second source is around 900 nm.

29. The device of claim 27, wherein the electronics further calculate a measure of oxygenation.

30. The device of claim 26, wherein the electronics are configured to instruct a user where to move the body part to improve the reflected light intensity.

31. The device of claim 24, wherein the device is a computing device.

32. The device of claim 31, wherein the computing device is portable.

33. The device of claim 32, wherein the computing device is a personal digital assistant.

36. A method comprising:

emitting electromagnetic radiation from a source into a volume of space;

reflecting the emitted radiation off an object in the volume of space;

detecting a position of the reflected radiation at a position sensitive detector;

modulating the emission and detection of the radiation to reduce an effect of ambient radiation on the detection; and

calculating a position of the object in the volume of space from the detected position of reflected radiation.

38. A method comprising:

emitting electromagnetic radiation from a plurality of sources in a plurality of direction through a transparent barrier, some of the radiation entering a volume of space behind a first side of the barrier;

reflecting the emitted radiation off an object behind the first side of the barrier;

detecting a position and intensity of the reflected radiation at a position sensitive detector behind a second side of the barrier;

modulating the radiation to reduce an effect of ambient radiation on the detection and identify radiation from different sources at the detector;

calculating a position of the object from the detected position of the reflected radiation;

comparing intensities of reflected radiation from the plurality of sources; and

identifying whether the object is located in the volume of space or on the surface of the first side of the barrier based on the comparison.

39. A method comprising:

emitting electromagnetic radiation from a source through a transparent barrier;

reflecting the emitted radiation off a body part of an organism placed on a surface of a first side of the barrier;

detecting a position and intensity of the reflected radiation at a position sensitive detector behind a second side of the barrier;

modulating the radiation to reduce an effect of ambient radiation on the detection;

calculating a position of the body part on the surface from the detected position of the reflected radiation; and

calculating a photoplethysmograph from changes to the reflected radiation intensity.

40. The method of claim 39, further comprising:

emitting electromagnetic radiation from a plurality of sources having unique wavelengths through the transparent barrier, the sources modulated to identify the sources of reflected radiation at the detector;

comparing the reflected radiation intensities from each source; and

calculating a measure of oxygenation from the comparison.