OPTICAL PRESSURE SENSOR

• US 20150342527A1
• Filed: 05/30/2014
• Published: 12/03/2015
• Est. Priority Date: 05/30/2014
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Karnik, Ryna, Shayesteh-pour, Hamid, Hingorani, Vinod L.
• Granted Patent: US 10,602,981 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61B 2562/0219 Inertial sensors, e.g. accelerometers, gyroscopes, tilt switches
• CPC Class Codes: A61B 2562/0247 Pressure sensors
• CPC Class Codes: A61B 5/0059 using light, e.g. diagnosis by transillumination, diascopy, fluorescence A61B5/0093, A61B5/1455, A61B5/02416 and A61B5/0261 take precedence
• CPC Class Codes: A61B 5/02427 Details of sensor
• CPC Class Codes: A61B 5/02438 with portable devices, e.g. worn by the patient
• CPC Class Codes: A61B 5/1123 Discriminating type of movement, e.g. walking or running A61B5/1116, A61B5/112 take precedence
• CPC Class Codes: A61B 5/486 Bio-feedback A61B5/375 takes precedence
• CPC Class Codes: A61B 5/681 Wristwatch-type devices
• CPC Class Codes: A61B 5/6843 Monitoring or controlling sensor contact pressure
• CPC Class Codes: A61B 5/6885 Monitoring or controlling sensor contact pressure
• 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: A61B 5/7214 using signal cancellation, e.g. based on input of two identical physiological sensors spaced apart, or based on two signals derived from the same sensor, for different optical wavelengths
• CPC Class Codes: A61B 5/7221 Determining signal validity, reliability or quality A61B5/7207 and A61B5/7217 take precedence
• CPC Class Codes: A61B 5/7267 involving training the classification device
• CPC Class Codes: A61B 5/742 using visual displays A61B5/339 takes precedence
• CPC Class Codes: G16H 50/70 for mining of medical data, e.g. analysing previous cases of other patients

Abstract

A pressure sensor comprises an optical source configured to illuminate the tissue of a user, and an optical sensor configured to measure reflected illumination from the tissue. A compute system is configured to output a pressure between a surface of the optical sensor and the tissue as a function of the measured reflected illumination.

Claims

1. A pressure sensor, comprising:

an optical source configured to illuminate tissue of a user;

an optical sensor configured to measure reflected illumination from the tissue; and

a compute system configured to output a pressure between a surface of the optical sensor and the tissue, the pressure determined as a function of the measured reflected illumination.

2. The pressure sensor of claim 1, where the optical source is configured to pulse on and off.

3. The pressure sensor of claim 2, where the compute system is configured to:

compare the measured reflected illumination to a predetermined baseline optical sensor output corresponding to the user; and

output an increased pressure between the surface of the optical sensor and the tissue responsive to an increase in a ratio of the measured reflected illumination to the predetermined baseline optical sensor output during time periods when the optical source is pulsed on.

4. The pressure sensor of claim 1, where the compute system is configured to:

indicate to the user to adjust an interface between the surface of the optical sensor and the tissue based on the output pressure.

5. The pressure sensor of claim 2, where the compute system is configured to:

indicate whether the pressure sensor is being worn based on the measured reflected illumination during time periods when the optical source is pulsed off.

6. The pressure sensor of claim 1, where the compute system is configured to:

indicate a heart rate of the user based on the measured reflected illumination.

7. The pressure sensor of claim 6, where indicating a heart rate of the user based on the measured reflected illumination comprises:

adjusting the measured reflected illumination based on the output pressure; and

indicating a heart rate of the user based on the adjusted measured reflected illumination.

8. The pressure sensor of claim 1, where the compute system is configured to:

adjust an intensity of light output by the optical source based on the output pressure.

9. The pressure sensor of claim 1, where the compute system is configured to:

classify the output pressure as representative of a type of predetermined activity.

10. The pressure sensor of claim 9, further comprising a motion sensor configured to determine movement of the pressure sensor over time, and where the compute system is further configured to:

classify the determined movement as representative of a type of predetermined activity.

11. A wearable computing device, comprising:

a pressure sensor configured to determine a pressure between a surface of the pressure sensor and tissue of a user over time; and

an activity classifying machine trained via machine learning to classify the determined pressure over time as representative of a type of predetermined activity.

12. The device of claim 11, where classifying the determined pressure over time as representative of a type of predetermined activity further comprises comparing the determined pressure to pressure data sets representative of each of a plurality of predetermined activities, and classifying the determined pressure as representative of a type of predetermined activity based on the comparison of the determined pressure to the pressure data sets.

13. The device of claim 11, where the pressure sensor further comprises:

an optical source configured to illuminate the tissue of the user; and

an optical sensor configured to measure reflected illumination from the tissue.

14. The device of claim 13, further comprising:

a heart rate determination module configured to output a heart rate based on the measured reflected illumination.

15. The device of claim 14, where the heart rate determination module is further configured to:

adjust the measured reflected illumination responsive to the determined pressure being outside a pressure range; and

output a heart rate based on the adjusted measured reflected illumination.

16. The device of claim 13, where the optical source is configured to pulse on and off, and wherein the pressure sensor is further configured to:

compare the measured reflected illumination to a predetermined baseline optical sensor output corresponding to the user; and

output an increased pressure between the surface of the optical sensor and the tissue responsive to an increase in a ratio of the measured reflected illumination to the predetermined baseline optical sensor output during time periods when the optical source is pulsed on.

17. The device of claim 16, where the pressure sensor is further configured to:

indicate whether the pressure sensor is being worn based on the measured reflected illumination during time periods when the optical source is pulsed off.

18. The device of claim 13, where the pressure sensor is further configured to:

adjust an intensity of light output by the optical source based on the determined pressure.

19. The device of claim 12, further comprising one or more motion sensors, and where the activity classifying machine is further trained via machine learning to:

receive a signal from the one or more motion sensors indicating movement of the wearable computing device over time;

compare the indicated movement to movement data sets representative of each of a plurality of predetermined activities; and

classify the indicated movement as representative of a type of predetermined activity based on the comparison of the indicated movement to the movement data sets.

20. A wearable computing device, comprising:

an optical source configured to illuminate tissue of a user;

an optical sensor configured to measure reflected illumination from the tissue; and

a compute system configured to;

output a heart rate based on the measured reflected illumination; and

output a pressure between a surface of the optical sensor and the tissue based on the measured reflected illumination.