Optical vital signs sensor

Patent metadata

Field	Value
Publication number	US-10034639-B2
Application number	US-201615297861-A
Country	US
Kind code	B2
Filing date	Oct 19, 2016
Priority date	Jan 16, 2015
Publication date	Jul 31, 2018
Grant date	Jul 31, 2018

Abstract

An optical vital signs sensor is provided which comprises at least one light source with a primary and a secondary light unit and a photo detector, a motion sensor configured to detect a motion of a user, a periodicity metric unit to analyze an output signal of the at least one motion sensor to detect a periodicity in its output signal and a control unit configured to control an operation of the at least one primary and secondary light unit and to activate the at least one secondary light unit in addition to the at least one primary light unit when the periodicity metric unit does not detect a periodicity in the output signal of the motion sensor.

First claim

The invention claimed is:

1. An optical vital signs sensor, comprising:
at least one light source having at least one primary and at least one secondary light unit each being configured to generate light, which is directed towards a skin of a user, said primary light unit being activated when the optical vital signs sensor is switched on, wherein the primary light unit emits light of a first color and the secondary light unit emits light of a second color different from the first color,
at least one photo detector unit having at least one photo diode configured to detect light which is indicative of a transmission or reflection of the light from the at least one primary and at least one secondary light unit in or from the skin of the user, wherein the at least one photodetector unit produces a detected light signal,
at least one motion sensor configured to detect a motion of the optical vital signs sensor,
a periodicity metric unit configured to analyze an output signal of the at least one motion sensor to determine whether or not the motion of the optical vital signs sensor is periodic,
a switching unit configured to control an operation of the at least one primary and secondary light unit, wherein the switching unit is configured to:
activate the at least one secondary light unit in addition to the at least one primary light unit when the periodicity metric unit determines that the motion is not periodic,
deactivate the at least one secondary light unit when the periodicity metric unit determines that the motion is periodic,
wherein the at least one primary light operates regardless of whether or not the motion is periodic, and

a motion artifact removal unit configured to remove motion artifacts from the detected light signal of the photo detector unit based on:
the output signal of the at least one motion sensor when the motion is determined to be periodic, and
the detected light signal including detected light of the second color from the at least one secondary light unit when the at least one secondary light unit is activated.

2. Optical vital signs sensor according to claim 1 , wherein the at least one primary light unit emits green light and/or the at least one secondary light unit emits red, yellow or infrared light.

3. An optical vital signs sensor according to claim 1 , wherein the switching unit is configured to deactivate the at least one secondary light unit with a predetettnined delay, if the periodicity metric unit has detettnined that the motion is periodic.

4. An optical vital signs sensor according to claim 1 , wherein the periodicity metric unit is configured to detect a resting of a user of the optical vital signs sensor based on the output signal of the photo detector unit, wherein the switching unit is configured to deactivate the at least one secondary light unit if a resting of the user is determined.

5. An optical vital signs sensor according to claim 4 , further comprising
a motion artifact removal unit which is configured to remove motion artifacts from the output signal of the photo detector unit, and
the switching unit is configured to deactivate the motion artifact removal unit if the periodicity metric unit has determined that a person is at rest.

6. Method of operating an optical vital signs sensor having at least one light source having at least one primary and at least one secondary light unit, at least one photo detector unit having at least one photo diode and a motion sensor, comprising the steps of:
activating a primary light unit to direct its light towards a skin of a user, when the optical vital signs sensor is switched on, wherein the primary light unit emits light of a first color and the secondary light unit emits light of a second color different from the first color,
detecting a light which is indicative of a transmission or reflection of the light from the at least one primary and/or at least one secondary light unit in or from the skin of the user,
detecting a motion of the optical vital signs sensor by a motion sensor,
analyzing an output signal of the at least one motion sensor to determine whether or not the motion of the optical vital signs sensor is periodic,
controlling an operation of the at least one primary light unit regardless of whether the motion is periodic,
activating the at least one secondary light unit in addition to the at least one primary light unit when the motion is determined to not be periodic;
deactivating the at least one secondary light unit when the motion is determined to be periodic; and
removing motion artifacts from the output signal based on the output signal of the motion sensor when the motion is determined to be periodic, and based on the detected light including detected light of the second color from the at secondary light unit when the at least one secondary light unit is activated.

7. The method according to claim 6 , wherein the at least one primary light unit emits green light and/or the at least one secondary light unit emits red, yellow or infrared light.

8. The method according to claim 6 , wherein the activating comprises deactivating the at least one secondary light unit with a predetermined delay, if motion is periodic.

9. The method according to claim 6 , further comprising:
detecting a resting of a user of based on the detected light; and
deactivating the at least one secondary light unit if a resting of the user is determined.

10. The method according to claim 9 , further comprising:
removing motion artifacts from the output signal of the photo detector unit, and
wherein the removing is omitted if the person is determined to be at rest.

11. A non-transitory machine-readable storage medium comprising instructions for execution by a processor, the medium comprising:
instructions for activating a primary light unit to direct its light towards a skin of a user, when the optical vital signs sensor is switched on, wherein the primary light unit emits light of a first color and a secondary light unit emits light of a second color different from the first color,
instructions for detecting a light which is indicative of a transmission or reflection of the light from the at least one primary and/or at least one secondary light unit in or from the skin of the user,
instructions for detecting a motion of the optical vital signs sensor by a motion sensor,
instructions for analyzing an output signal of the at least one motion sensor to determine whether or not the motion of the user is periodic,
instructions for controlling an operation of the at least one primary light unit regardless of whether the motion is periodic,
instructions for activating the at least one secondary light unit in addition to the at least one primary light unit when the motion is determined to not be periodic;
instructions for deactivating the at least one secondary light unit when the motion is determined to be periodic; and
instructions for removing motion artifacts from the output signal based on the output signal of the motion sensor when the motion is determined to be periodic, and based on the detected light including detected light of the second color from the at secondary light unit when the at least one secondary light unit is activated.

12. The non-transitory machine-readable storage medium according to claim 11 , wherein the at least one primary light unit emits green light and/or the at least one secondary light unit emits red, yellow or infrared light.

13. The non-transitory machine-readable storage medium according to claim 11 , wherein the instructions for activating comprise instructions for deactivating the at least one secondary light unit w

Assignees

• Koninklijke Philips Nv

Inventors

• Van Dinther Cornelus Hendricus Bertus Arnoldus
• Roovers David Antoine Christian Marie

Classifications

• A61B2560/0209

  adapted for power saving · CPC title

• A61B5/11

  Measuring movement of the entire body or parts thereof, e.g. head or hand tremor or mobility of a limb {(A61B5/1038 takes precedence; motion detection to correct for motion artifacts in physiological signals A61B5/721)} · CPC title

• A61B5/1116

  Determining posture transitions · CPC title

• A61B5/1118

  Determining activity level · CPC title

• A61B5/02416

  using photoplethysmograph signals, e.g. generated by infrared radiation (A61B5/14552 takes precedence) · CPC title