MEASURING OF A PHYSIOLOGICAL PARAMETER USING A WEARABLE SENSOR

• US 20170347957A1
• Filed: 12/01/2015
• Published: 12/07/2017
• Est. Priority Date: 12/18/2014
• Status: Active Grant

• Current Assignee: Koninklijke Philips N.V.
• Original Assignee: Koninklijke Philips N.V.
• Inventors: van den Ende, Daan Anton, Haakma, Reinder, Johnson, Mark Thomas, Boekhorst, Frederick Maria, Kovacevic Milivojevic, Milica, Hakkens, Franciscus Johannes Gerardus, Hilgers, Achim, Hendriks, Cornelis Petrus, Ubachs, Rene Leonardus Jacobus Marie, Pelssers, Eduard Gerard Marie
• Granted Patent: US 10,575,780 B2
• Time in Patent Office: Days
• CPC Class Codes: A61B 5/02416 using photoplethysmograph signals, e.g. generated by infrared radiation A61B5/14552 takes 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 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/25 Bioelectric electrodes therefor
• CPC Class Codes: A61B 5/318 Heart-related electrical modalities, e.g. electrocardiography [ECG]
• CPC Class Codes: A61B 5/6824 Arm or wrist
• CPC Class Codes: A61B 5/6843 Monitoring or controlling sensor contact pressure
• CPC Class Codes: A61B 5/6844 Monitoring or controlling distance between sensor and tissue
• CPC Class Codes: A61B 5/7207 of noise induced by motion artifacts
• CPC Class Codes: A61B 8/44 Constructional features of the ultrasonic, sonic or infrasonic diagnostic device
• CPC Class Codes: F03G 7/005 Electro-chemical actuators; Actuators having a material for absorbing or desorbing gas, e.g. a metal hydride; Actuators using the difference in osmotic pressure between fluids; Actuators with elements stretchable when contacted with liquid rich in ions, with UV light, with a salt solution
• CPC Class Codes: H10N 30/20 with electrical input and mechanical output, e.g. functioning as actuators or vibrators
• CPC Class Codes: H10N 30/857 Macromolecular compositions

Abstract

An apparatus comprises a sensor for measuring a physiological parameter of a subject, wherein the physiological parameter sensor is adapted to be worn by the subject; an actuator comprising an electro-active polymer material, EAP, portion for adjusting the position of the physiological parameter sensor relative to the subject; a feedback sensor for measuring movement of the physiological parameter sensor and/or the subject; a controller configured to process the measurements of the feedback sensor and to adjust the position of the actuator based on information from the feedback sensor.

Claims

1. A wearable sensor apparatus, comprising:

a sensor for measuring a physiological parameter of a subject, wherein the sensor is adapted to be worn by the subject;

an actuator comprising an electro-active polymer material portion for adjusting the position of the sensor relative to the subject;

a feedback sensor for measuring movement of the physiological parameter sensor and/or the subject; and

a controller configured to process a measurement of the feedback sensor and to control the actuator to adjust the position of the sensor based on the measurement of the feedback sensor, wherein the actuator is arranged to adjust the position of the physiological parameter sensor relative to the subject by exerting a force on the physioloigcal parameter sensor.

2. The apparatus of claim 1, wherein the feedback sensor is configured to measure a change in the contact force between the sensor and the subject.

3. The apparatus of claim 2 further comprising a coupling member disposed on the sensor and arranged between the sensor and the subject in use.

4. The apparatus of claim 1, wherein the feedback sensor is configured to measure a change in a distance between the sensor and the subject.

5. The apparatus of any preceding claim, wherein the sensor comprises:

a housing having walls which define an internal area; and

a sensor element disposed inside the internal area of the housing,

wherein the feedback sensor is configured to measure movement of the housing relative to the subject.

6. The apparatus of claim 1, wherein the sensor comprises the feedback sensor, and wherein the controller is configured to process a signal from the sensor and to adjust the position of the actuator based on the signal of the sensor.

7. The apparatus of claim 6, wherein the sensor comprises:

a housing having walls which define an internal area;

a light source disposed in the internal area of the housing; and

a light sensor disposed inside the internal area of the housing,

wherein the controller is configured to process a signal of the light sensor and to adjust the position of the actuator based on the signal of the light sensor.

8. The apparatus of claim 7 further comprising an external light sensor disposed outside of the housing, and wherein the controller is configured to process a signal of the external light sensor and to adjust the position of the actuator based the light signal of the external light sensor and the light sensor of the sensor.

9. The apparatus of claim 7, further comprising:

a signal generator adapted to;

generate a first electrical alternating signal, for use in sensing, having a first frequency;

generate a second electrical alternating signal, for use in actuation, having a second frequency wherein the second frequency is substantially the same as the first frequency; and

apply the first electrical signal to the sensor;

apply the second electrical signal to the actuator,

wherein the apparatus further comprises a detector for detecting a difference between the first electrical signal and the second electrical signal

10. The apparatus of claim 1, wherein the actuator further comprises a strain sensitive electrode portion disposed on the electroactive polymer portion, and the apparatus further comprises:

a first power or voltage source arranged to apply a first voltage to the electroactive polymer portion of the actuator; and

a second power or voltage source arranged to apply a second voltage to the strain sensitive electrode portion of the actuator,

wherein the controller is arranged to measure a change in resistivity of the strain sensitive electrode and to adjust the position of the actuator based on the measured change in resistivity.

11. The apparatus of claim 1, wherein the sensor comprises a housing and the actuator is arranged to exert a force on the housing in response to an actuation signal from the controller.

12. A method for measuring a physiological parameter using the device of claim 1, comprising:

(i) obtaining a signal using the feedback sensor;

(ii) determining if the sensor has moved relative to the subject, based on the signal of the feedback sensor;

(iii) if the sensor has moved relative to the subject, adjusting the position of the actuator according to the measured movement, wherein the actuator is adjusted to directly contact the sensor so that the actuator exerts a force on the physiological parameter sensor.

13. The method of claim 12, wherein step (ii) comprises comparing a measurement of contact pressure to a reference value for contact pressure.

15. The method of claim 12, further comprising the steps of

(iv) applying a first alternating signal having a first frequency to the actuator;

(v) applying a second alternating signal having a second frequency to the physiological parameter sensor, wherein the second frequency is the same as the first frequency; and

(vi) comparing the first alternating signal and the second alternating signal to determine if the sensor has moved.

14. (canceled)