# US 11,906,303 B2 · Wearable skin vibration or silent gesture detector

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- Number: US 11,906,303 B2
- Document ID: US11906303B2
- Status: Granted
- Kind: B2
- Application number: 17/894,571
- Filed: 2022-08-24
- Published: 2022-12-22
- Granted: 2024-02-20
- Earliest claimed: 2019-05-24
- Assignees: Apple Inc.
- Applicants: Apple Inc.
- Inventors: Mehmet Mutlu; Ahmet Fatih Cihan
- Web page: https://patentgrep.com/patent/US11906303B2

## CPC

- G01B 9/02092: {Self-mixing interferometers, i.e. feedback of light from object into laser cavity}
- G01B 11/161: {by interferometric means}
- G06F 3/011: {Arrangements for interaction with the human body, e.g. for user immersion in virtual reality (blind teaching G09B21/00)}
- G06F 3/012: {Head tracking input arrangements}
- G06F 3/017: {Gesture based interaction, e.g. based on a set of recognized hand gestures (interaction based on gestures traced on a digitiser G06F3/04883)}
- G06F 3/167: {Audio in a user interface, e.g. using voice commands for navigating, audio feedback}
- H04R 1/1091: {Details not provided for in groups H04R1/1008 - H04R1/1083}
- H04R 5/033: Headphones for stereophonic communication {(details thereof, e.g. relating to batteries, cables or control elements H04R1/10)}
- H04R 2460/13: Hearing devices using bone conduction transducers
- 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)
- H04R: LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS (producing sounds with frequency not determined by supply frequency G10K)

## Abstract

Disclosed herein are wearable devices, their configurations, and methods of operation that use self-mixing interferometry signals of a self-mixing interferometry sensor to recognize user inputs. The user inputs may include voiced commands or silent gesture commands. The devices may be wearable on the user's head, with the self-mixing interferometry sensor configured to direct a beam of light toward a location on the user's head. Skin deformations or vibrations at the location may be caused by the user's speech or the user's silent gestures and recognized using the self-mixing interferometry signal. The self-mixing interferometry signals may be used for bioauthentication and/or audio conditioning of received sound or voice inputs to a microphone.

## Claims

### Claim 1

A wearable device, comprising:
a frame configured to attach the wearable device to a user and to direct a beam of light toward a skin portion of the user;
a self-mixing interferometry sensor mounted to the frame and configured to emit the beam of light; and
an interpreter configured to:
receive a self-mixing interferometry signal from the self-mixing interferometry sensor;
detect skin vibration information in the self-mixing interferometry signal; and
transmit one or more signals responsive to a detection of the skin vibration information in the self-mixing interferometry signal.

### Claim 2 (depends on 1)

The wearable device of claim 1, wherein:
the frame defines an earbud;
the wearable device further comprises:
a microphone; and
an in-ear speaker;
the frame directs the beam of light toward a location in an ear of the user; and
the interpreter identifies a voiced command of the user using the skin vibration information.

### Claim 3 (depends on 1)

The wearable device of claim 1, wherein:
the frame defines an eyeglass set including an arm;
the self-mixing interferometry sensor is mounted to the arm;
the arm directs the beam of light toward a location proximate to a temporal bone of the user; and
the interpreter identifies a voiced command of the user based on the skin vibration information.

### Claim 4 (depends on 1)

The wearable device of claim 1, wherein interpreter is further configured to:
detect temporomandibular joint movement information corresponding to the skin vibration information in the self-mixing interferometry signal.

### Claim 5 (depends on 4)

The wearable device of claim 4, wherein interpreter is further configured to:
identify the temporomandibular joint movement information as a silent gesture command of the user.

### Claim 6 (depends on 1)

The wearable device of claim 1, wherein:
the beam of light is a first beam of light;
the wearable device directs a second beam of light toward the skin portion of the user; and
the interpreter is configured to receive a second self-mixing interferometry signal based at least in part on the second beam of light.

### Claim 7 (depends on 1)

The wearable device of claim 1, wherein:
the beam of light is a laser light beam emitted by a laser diode;
a bias current of the laser diode is modulated with a sine wave; and
the interpreter is configured to use a time domain I/O analysis to detect the skin vibration information in the self-mixing interferometry signal.

### Claim 8 (depends on 1)

The wearable device of claim 1, wherein:
the beam of light is a laser light emitted by a laser diode;
a bias current of the laser diode is modulated with a triangle wave; and
the interpreter is configured to use a spectrum analysis to detect the skin vibration information in the self-mixing interferometry signal.

### Claim 9 (depends on 1)

The wearable device of claim 1, wherein the interpreter is a command interpreter configured to identify a voiced command encoded in the skin vibration information.

### Claim 10

A device, comprising:
a frame configured to be worn by a user;
a self-mixing interferometry sensor mounted to the frame and configured to emit a beam of light toward a location on a skin portion of the user; and
an interpreter configured to:
receive a self-mixing interferometry signal from the self-mixing interferometry sensor;
detect a first skin vibration information in the self-mixing interferometry signal;
detect a second skin vibration information in the self-mixing interferometry signal, wherein the second skin vibration information includes vibration information different from the first skin vibration information; and
transmit one or more signals responsive to a detection of the second skin vibration information in the self-mixing interferometry signal, the one or more signals indicating a movement unrelated to a voiced command.

### Claim 11 (depends on 10)

The device of claim 10, further comprising:
a microphone; wherein:
the interpreter is configured to:
receive an output of the microphone;
determine the first skin vibration information in the self-mixing interferometry signal based at least in part on a voiced command from the output of the microphone; and
send one more second signals indicating a movement related to the voiced command.

### Claim 12 (depends on 11)

The device of claim 11, the interpreter is configured to:
detect a correlation of the voiced command of the user with a voice pattern detected in the first skin vibration information.

### Claim 13 (depends on 11)

The device of claim 11, further comprising:
a bioauthentication circuit configured to:
authenticate the voiced command using a self-mixing interferometry signal of the self-mixing interferometry sensor; wherein:
the self-mixing interferometry signal includes the first skin vibration information.

### Claim 14 (depends on 13)

The device of claim 13, the bioauthentication circuit is configured to:
determine that the user was speaking during a time interval of the received output of the microphone based at least in part on the first skin vibration information; and
authenticate the voiced command using a detection that the user was speaking during the time interval.

### Claim 15 (depends on 10)

The device of claim 10, wherein:
the frame is a head-mountable frame; and
the location on the skin portion of the user is proximate to at least one of a temporal bone and a parietal bone.

### Claim 16

A device, comprising:
a frame configured to be worn by a user;
a self-mixing interferometry sensor mounted to the frame and configured to emit a beam of light toward skin of the user; and
an audio conditioning circuit configured to:
receive a self-mixing interferometry signal from the self-mixing interferometry sensor;
detect skin vibration information in the self-mixing interferometry signal; and
determine time intervals of non-speech of the user based at least in part on a detection of the skin vibration information.

### Claim 17 (depends on 16)

The device of claim 16, further comprising:
a microphone configured to produce an audio signal; wherein the audio conditioning circuit is configured to:
modify the audio signal using the self-mixing interferometry signal of the self-mixing interferometry sensor based at least in part on a determination of the time intervals of non-speech of the user.

### Claim 18 (depends on 17)

The device of claim 17, wherein the audio conditioning circuit is configured to modify the audio signal is further configure to:
suppress background noise during a time segment in the determined time intervals of non-speech of the user modify the audio signal.

### Claim 19 (depends on 16)

The device of claim 16, further comprising:
a microphone configured to produce an audio signal; wherein the audio conditioning circuit is configured to:
determine time intervals of speech of the user based at least in part on the detection of the skin vibration information; and
refrain from modifying the audio signal based at least in part on a determination of the time intervals of speech of the user.

### Claim 20 (depends on 16)

The device of claim 16, wherein:
the beam of light is a laser light beam emitted by a laser diode; and
the audio conditioning circuit is configured to modify an audio signal using at least one of:
a time domain I/O analysis of the self-mixing interferometry signal when a sine wave modulation is applied to a bias current of the laser diode, and
a spectrum analysis of the self-mixing interferometry signal when a triangle wave modulation is applied to the bias current of the laser diode.