SENSOR AND METHOD FOR CONTINUOUS HEALTH MONITORING

• US 20150057511A1
• Filed: 03/27/2013
• Published: 02/26/2015
• Est. Priority Date: 03/28/2012
• Status: Active Grant

• Current Assignee: Wayne State University
• Original Assignee: Wayne State University
• Inventors: Basu, Amar Sarbbasesh
• Granted Patent: US 10,219,709 B2
• Time in Patent Office: Days
• US Class Current: 600/323
• CPC Class Codes: A61B 2562/0233 Special features of optical sensors or probes classified in A61B5/00
• CPC Class Codes: A61B 2562/04 Arrangements of multiple sensors of the same type
• CPC Class Codes: A61B 2562/046 in a matrix array
• CPC Class Codes: A61B 5/02007 Evaluating blood vessel condition, e.g. elasticity, compliance
• CPC Class Codes: A61B 5/02125 of pulse wave propagation time
• CPC Class Codes: A61B 5/02433 for infrared radiation
• CPC Class Codes: A61B 5/0285 Measuring or recording phase velocity of blood waves
• CPC Class Codes: A61B 5/14552 Details of sensors specially adapted therefor
• CPC Class Codes: A61B 5/6826 Finger

Abstract

An optical proximity sensor assembly includes an optical proximity sensor with an IR LED emitting light having an infrared wavelength, an IR photo detector sensitive to the infrared wavelength, an optical barrier blocking direct light rays from the LED to the IR photo detector and permitting reflected light rays to reach the at least one photo detector; and an electronic integrated circuit with an amplifier for amplifying a signal detected by the photo detector, an analog to digital converter, LED drivers, noise reduction and ambient light cancellation circuitry, and a digital interface for communication with a microcontroller. The optical proximity sensor is accommodated on a wearable carrier. A single sensor may include a plurality of identical or different LEDs, a plurality of photodiodes, or both. Also, several sensors may be placed on a person'"'"'s skin along a vascular path to obtain data relating to blood flow and artery stiffness.

Claims

1. An optical proximity sensor assembly for cardiovascular monitoring, the optical proximity sensor assembly comprising:

an optical proximity sensor having

a first IR LED emitting light having an infrared wavelength,

a first IR photo detector sensitive to the infrared wavelength; and

an electronic integrated circuit with an amplifier for amplifying a signal detected by the photo detector, an analog to digital converter, LED drivers, noise reduction and ambient light cancellation circuitry, and a digital interface for communication with a microcontroller; and

a wearable carrier accommodating the optical proximity sensor and configured for placing the optical proximity sensor in contact with skin.

2. The assembly of claim 1, wherein the optical proximity sensor further comprises a transparent cover covering the first IR LED and the first IR photo detector.

3. The optical proximity sensor of claim 1, further comprising an optical barrier between the first IR LED and the first IR photo detector, the optical barrier blocking direct light rays from the first IR LED to the first IR photo detector and permitting reflected light rays to reach the at least one photo detector.

4. The assembly of claim 1, wherein the analog-to-digital converter has at least a 12-bit resolution.

5. The assembly of claim 1, further comprising a wireless transmission system and an electronic processor with an operating system compatible with a remote wireless device.

6. The assembly of claim 1, wherein the optical proximity sensor further comprises a visible light blocking filter shielding the first IR photo detector.

7. The assembly of claim 1, further comprising a battery integrated with the wearable carrier, the battery having a capacity sufficient to operate the optical proximity sensor assembly for at least 25 hours.

8. The assembly of claim 1, wherein the first IR LED is pulsed.

9. The assembly of claim 8, wherein the LED is pulsed at a unique frequency for improving a signal-to-noise ratio.

10. The assembly of claim 8, wherein the LED is pulsed at a frequency of at least about 100 Hz.

11. The assembly of claim 8, wherein the LED is pulsed at a frequency of at least about 1 kHz.

12. The assembly of claim 8, wherein the LED is pulsed with a pulse width of at most about 100 μ

s.

13. The assembly of claim 1, wherein the IR LED, the first IR photo detector and other components of the assembly are arranged on two circuit boards.

14. The assembly of claim 13, wherein at least the first IR LED and the first IR photo detector are arranged in a package covering an area of at most about 1 cm².

15. The assembly of claim 14, wherein the area is at most about 20 mm².

16. The assembly of claim 15, wherein the area is at most about 17 mm².

17. The assembly of claim 15, further comprising a battery arranged to reflect the light emitted by the first IR LED toward the first IR photo detector.

18. The assembly of claim 15, wherein the wearable carrier is a finger ring, on which a first electronic board and a second electronic board are arranged, the ring forming electronic conduits connecting the first and second electronic boards.

19. The assembly of claim 15, wherein the wearable carrier is a clip wearable on an earlobe, a first electronic board and a second electronic board being arranged on the clip, the clip forming electric conduits connecting the first and second electronic boards.

20. The assembly of claim 1, wherein the sensor comprises a second IR photo detector arranged on a side of the first IR LED opposite the first IR photo detector.

21. The assembly of claim 20 configured for pulse wave velocity measurements.

22. The assembly of claim 1, further comprising a second LED.

23. The assembly of claim 22, wherein the first IR LED and the second LED are pulsed at a different frequencies so as to enable frequency multiplexing.

24. The assembly of claim 22, wherein the first IR LED and the second LED are pulsed in an alternating order so as to enable time multiplexing.

25. The assembly of claim 22, wherein the second LED is a second IR LED arranged on a side of the first IR photo detector opposite the first IR LED.

26. The assembly of claim 25 configured to perform pulse velocity measurements.

27. The assembly of claim 22, wherein the second LED emits red light.

28. the assembly of claim 27, wherein the first IR photo detector is also sensitive to the red light emitted by the second LED

29. The assembly of claim 27 configured to perform blood oxygenation measurements.

30. An optical proximity sensor assembly system comprising a plurality of optical proximity sensor assemblies according to claim 1.

31. A method of sensing biometrical data with an optical proximity sensor assembly system according to claim 30, the method comprising the steps of:

placing a first one of the plurality of optical proximity sensor assemblies in a first location on skin of a person in the vicinity of an artery suited for measuring a pulse from the person'"'"'s heart;

placing a second one of the plurality of optical proximity sensor assemblies in a second location on skin of a person in the vicinity of the artery suited for measuring the pulse from the person'"'"'s heart;

the second location being downstream from the first location;

comparing measurements of the first one and the second one of the plurality of optical proximity sensor assemblies;

generating an output representative of blood flow restrictions between the first location and the second location.