# US 11,992,337 B2 · Wearable self-mixing interferometry device used to sense physiological conditions > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,992,337 B2 - Document ID: US11992337B2 - Status: Granted - Kind: B2 - Application number: 17/891,406 - Filed: 2022-08-19 - Published: 2022-12-08 - Granted: 2024-05-28 - Earliest claimed: 2019-09-24 - Assignees: Apple Inc. - Applicants: Apple Inc. - Inventors: Ahmet Fatih Cihan; Adrian Z. Harb; Mehmet Mutlu; Mengshu Huang; Stephen E. Dey; Yuhao Pan - Web page: https://patentgrep.com/patent/US11992337B2 ## CPC - A61B 5/4884: {inducing physiological or psychological stress, e.g. applications for stress testing} - A61B 5/6826: {Finger} - A61B 5/02427: {Details of sensor} - A61B 5/02438: {with portable devices, e.g. worn by the patient} - A61B 5/441: {Skin evaluation, e.g. for skin disorder diagnosis} - A61B 5/6802: {Sensor mounted on worn items} - A61B 5/6844: {Monitoring or controlling distance between sensor and tissue} - G01B 9/02049: {characterised by particular mechanical design details} - G01B 9/02092: {Self-mixing interferometers, i.e. feedback of light from object into laser cavity} - G06F 1/163: {Wearable computers, e.g. on a belt} - H01S 5/183: having only vertical cavities, e.g. vertical cavity surface-emitting lasers [VCSEL] - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) - G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - H01S: DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL ## Abstract A wearable electronic device including a housing that is worn by a user and a SMI sensor contained within the housing. The SMI sensor may include an emitter that outputs coherent light toward the skin of a user when the housing is worn by the user. The SMI sensor may also include a detector that detects a portion of the coherent light reflected towards the sensor and generates electrical signals that indicate displacements of the skin based on the portion of coherent light received at the detector. The housing may include a transmitter that is operatively coupled with the SMI sensor and is configured to transmit physiological data to a receiving device based on electrical signals output from the SMI sensor. ## Claims ### Claim 1 An electronic device, comprising: a housing configured to be worn by a user; a sensor contained within the housing and comprising: a vertical cavity surface emitting laser (VCSEL) positioned in the housing and configured to output coherent light toward the user; a detector configured to: detect a portion of the coherent light that is returned towards the sensor; and generate electrical signals corresponding to displacements of a body part of the user based on the portion of the coherent light; and a transmitter operatively coupled with the sensor and configured to transmit sensor data based on the electrical signals. ### Claim 2 (depends on 1) The electronic device of claim 1, wherein the housing comprises a band configured to wrap around the body part of the user and maintain a gap between the VCSEL and a skin surface of the user when the housing is worn by the user. ### Claim 3 (depends on 1) The electronic device of claim 1, further comprising a processing unit configured to determine a heart rate of the user from the sensor data. ### Claim 4 (depends on 3) The electronic device of claim 3, further comprising a display configured to output a visual representation of the heart rate. ### Claim 5 (depends on 1) The electronic device of claim 1, wherein the detector is configured to generate the electrical signals corresponding to displacements of tissue beneath a skin surface of a user. ### Claim 6 (depends on 5) The electronic device of claim 5, wherein the generated electrical signals correspond to displacements of blood vessels of the user. ### Claim 7 (depends on 1) The electronic device of claim 1, further comprising a lens coupled with the housing and configured to focus the coherent light on the body part when the housing contacts the user. ### Claim 8 (depends on 1) The electronic device of claim 1, wherein: the VCSEL is a first VCSEL; the detector is a first detector; the sensor comprises: a second VCSEL positioned in the housing and configured to output coherent light toward the user; and a second detector configured to detect a portion of the coherent light emitted from the second VCSEL and returned towards the sensor. ### Claim 9 (depends on 1) The electronic device of claim 1, wherein the VCSEL and the detector comprise a same structure. ### Claim 10 An electronic device, comprising: an emitter configured to output coherent light toward a body part of a user when the electronic device is worn by the user; and a detector configured to detect a portion of the coherent light returned from the user and generate electrical signals based on the portion of the coherent light; a transmitter operatively coupled with the sensor, the transmitter configured to transmit physiological data based on the electrical signals; and a housing that at least partially encircles a limb of a user and contains the emitter, the detector and the transmitter, the housing configured to position the emitter at a distance from the body part of the user. ### Claim 11 (depends on 9) The electronic device of claim 9, wherein the emitter and detector comprise a self-mixing interferometer (SMI) sensor. ### Claim 12 (depends on 9) The electronic device of claim 9, wherein: the emitter is a vertical cavity surface emitting laser (VCSEL); the detector is the VCSEL; and the VCSEL is configured to output the electrical signals based on a difference between the outputted coherent light and the portion of coherent light returned from the user. ### Claim 13 (depends on 9) The electronic device of claim 9, further comprising an optical element positioned between the emitter and the user, wherein the optical element is configured to direct the coherent light toward the body part of the user. ### Claim 14 (depends on 12) The electronic device of claim 12, wherein the optical element is configured to direct the portion of the coherent light returned from the user to the detector. ### Claim 15 (depends on 9) The electronic device of claim 9, wherein: the emitter is configured to output the coherent light to subcutaneous structure of the user; and the detector is configured to detect the portion of the coherent light returned from the subcutaneous structure. ### Claim 16 (depends on 14) The electronic device of claim 14, wherein: the subcutaneous structure comprises a blood vessel of a user; and the generated electrical signals correspond to movement of the blood vessel of the user. ### Claim 17 A method for measure physiological parameters of a user, the method comprising: generating coherent light within a vertical cavity surface emitting laser (VCSEL) of a self-mixing interferometer (SMI) and emitting the coherent light towards a body part of the user; detecting, using the SMI, a self-mixing interference between the generated coherent light and a portion of the coherent light returned toward the Marginating, at the SMI, an electrical signal based on the self-mixing interference; determining a physiological parameter based on the electrical signal; and outputting the physiological parameter. ### Claim 18 (depends on 16) The method of claim 16 wherein: determining the physiological parameter comprises determining displacement of a subcutaneous tissue of the user; and the displacements of the body part are tracked for a duration. ### Claim 19 (depends on 17) The method of claim 17, wherein the physiological parameter comprises a heart rate of the user over the duration. ### Claim 20 (depends on 18) The method of claim 18, wherein outputting the physiological parameter comprises displaying a visual indication of the heart rate. ### Claim 21 (depends on 16) The method of claim 16, wherein the SMI sensor is positioned in a housing that at least partially encircles a limb of the user.