Sensor and method for continuous health monitoring

• US 10,219,709 B2
• Filed: 03/27/2013
• Issued: 03/05/2019
• Est. Priority Date: 03/28/2012
• Status: Active Grant

• Current Assignee: Wayne State University
• Original Assignee: Wayne State University
• Inventors: Basu, Amar Sarbbasesh
• Primary Examiner(s): Winakur, Eric
• Assistant Examiner(s): Fardanesh, Marjan
• Application Number:
  US14/388,018
• Publication Number:
  US 20150057511A1
• Time in Patent Office: 2,169 Days
• Field of Search: None
• 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;

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;

wherein the wearable carrier is a clip wearable on an earlobe, the clip including an electronic board and a battery arranged on opposite sides of the clip to be placed on opposite sides of the earlobe, the clip forming electric conduits connecting the electronic board with the battery, the battery being arranged to reflect the light emitted by the first IR LED toward the first IR photo detector;

wherein the first IR LED, the first IR photo detector, and the electronic integrated circuit are mounted on the electronic board, which covers an area of at most 25 mm².

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, wherein the battery has a capacity sufficient to operate the optical proximity sensor assembly for at least 24 hours.

8. The assembly of claim 1, wherein the first IR LED is pulsed and is configured to operate in a low-duty-cycle mode by burst operation.

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

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

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

s.

12. The assembly of claim 1, further comprising a second circuit board including the battery.

13. The assembly of claim 1, wherein the area is at most about 20 mm².

14. The assembly of claim 13, wherein the area is at most about 17 mm².

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

16. The assembly of claim 15 configured for pulse wave velocity measurements.

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

18. The assembly of claim 17, wherein each of the first IR LED and the second LED is pulsed at a unique frequency for improving a signal-to-noise ratio.

19. The assembly of claim 17, wherein the first IR LED and the second LED are pulsed at different frequencies so as to enable frequency multiplexing.

20. The assembly of claim 17, wherein the first IR LED and the second LED are pulsed in an alternating order so as to enable time multiplexing.

21. The assembly of claim 17, wherein the second LED is a second IR LED arranged on a lateral side of the first IR photo detector opposite the first IR LED on the electronic board.

22. The assembly of claim 21 configured to perform pulse velocity measurements.

23. The assembly of claim 17, wherein the second LED emits red light.

24. The assembly of claim 23, wherein the first IR photo detector is also sensitive to the red light emitted by the second LED.

25. The assembly of claim 23 configured to perform blood oxygenation measurements.

26. The assembly of claim 1, further comprising a second electronic board on the side of the battery, opposite the first electronic board.

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

28. 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;

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;

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

a wireless transmission system and an electronic processor with an operating system compatible with a remote wireless device; and

a rechargeable battery;

wherein the wearable carrier is a clip wearable on an earlobe, the clip including an electronic board and a battery arranged on opposite sides of the clip, the clip forming electric conduits connecting the electronic board with the battery;

wherein the first IR LED, the first IR photo detector, and the electronic integrated circuit are mounted on the electronic board, which covers an area of at most 25 mm²;

wherein the battery is configured to reflect the light emitted by the first IR LED toward the first IR photo detector.