Granted Patent B2

US 12,659,653 · App. 18/311,264 · Granted Jun 16, 2026

Inventors: Farrokh Ayazi (Atlanta, GA); Pranav Gupta (Atlanta, GA); Yaesuk Jeong (Atlanta, GA)

Assignee: Georgia Tech Research Corporation

H04R1/46B81B7/02G01P15/097G01P15/125H04R1/04H04R19/04B81B2201/0235B81B2201/0257B81B2203/0154B81B2203/04H04R2201/003

Abstract

Claims (124)

1 . A device comprising:

a suspended proof mass; and

a sensing electrode separated from the suspended proof mass by a sub-micron sensing gap;

wherein the device:

is sensitive to vibrations from a contact source;

is without sensitivity to air-borne acoustic emissions;

has an operational bandwidth ranging from DC to 10 k Hz;

is configured to sense frequencies in both:

a range of from DC to 20 Hz resultant from tilt and/or motion; and

a range of from 20 Hz to 10 k Hz resultant from vibration and/or acoustics;

operates in vacuum of smaller than or equal to 50 Torr; and has out-of-plane sensitivity and micro-g resolution.

2 . The device of claim 1 , wherein;

the contact source is a human body; and

the device is configured to capture wideband cardio- and pulmonary-induced vibrations from chest wall movements in an infrasonic range of from DC to 20 Hz.

3 . The device of claim 2 , wherein the out-of-plane sensitivity of the device enables mounting and placement of the device onto skin of an individual as the device has unidirectional sensitivity to sounds emanating from the human body and relatively orthogonal to a surface of the skin.

4 . The device of claim 1 , wherein the device is hermetically-sealed.

5 . The device of claim 1 , wherein the sub-micron sensing gap is a nano sensing gap.

6 . A hermetically-sealed contact microphone device comprising:

a suspended proof mass; and

a nano-gap capacitive electrode separated from the suspended proof mass;

wherein the device;

has out-of-plane sensitivity;

is sensitive to vibrations from a contact source;

is without sensitivity to air-borne acoustic emissions;

has micro-g resolution;

has an operational bandwidth ranging from DC to 10 k Hz;

is configured to sense frequencies in both:

a range of from DC to 20 Hz resultant from tilt and/or motion; and

a range of from 20 Hz to 10 k Hz resultant from vibration and/or

acoustics; and

operates in a vacuum of smaller than or equal to 50 Torr.

7 . The device of claim 6 further comprising a nano-gap capacitive damping electrode;

wherein the:

suspended proof mass is suspended by a supporting flexure;

device has a resonant frequency of greater than 10 k Hz; and

resonant frequency of the device is tunable via adjustment of one or more dimensions of the supporting flexure.

8 . The device of claim 7 further comprising a substrate;

wherein the:

supporting flexure is attached to the substrate;

first proof mass is configured to move out-of-plane of the substrate; and

device has a vibration acceleration sensitivity of better than 10 μg√Hz.

9 . The device of claim 8 , wherein the device comprises an out-of-plane differential accelerometer.

10 . An out-of-plane differential accelerometer comprising:

a suspended proof mass; and

a sensing electrode separated from the suspended proof mass by a nano sensing gap;

wherein the out-of-plane differential accelerometer:

has out-of-plane sensitivity and micro-g resolution;

is configured to sense frequencies in both:

a range of from DC to 20 Hz resultant from tilt and/or motion; and

a range of from 20 Hz to 10 k Hz resultant from vibration and/or acoustics; and

has a resonant frequency of greater than 10 k Hz.

11 . The out-of-plane differential accelerometer of claim 10 further comprising:

a torsional tether; and

one or more additional sensing electrodes;

wherein:

the suspended proof mass comprises hinged portions rotatable about the torsional tether;

each sensing electrode is separated from the hinged portions of the suspended proof mass by a nano capacitive gap;

the out-of-plane differential accelerometer has an operational bandwidth ranging from DC to 10,000 Hz determined by the resonant frequency of the out-of-plane differential accelerometer; and

the resonant frequency of the out-of-plane differential accelerometer is tunable

via adjustment of a width of one or more of the nano capacitive gaps.

12 . The out-of-plane differential accelerometer of claim 11 further comprising a substrate;

wherein:

the torsional tether is attached to the substrate;

the suspended proof mass is configured to move out-of-plane of the substrate;

the out-of-plane differential accelerometer is hermetically-sealed and configured to maintain a vacuum environment of smaller than or equal to 50 Torr; and

at least one of:

the hinged portions of the proof mass are each substantially thicker than the sensing electrodes;

the hinged portions of the proof mass are mirror symmetric;

the out-of-plane differential accelerometer has tri-axial vibration sensitivity including in the normal direction to the plane of the substrate and in the plane of the substrate; or

the out-of-plane differential accelerometer has a vibration acceleration sensitivity of better than 100 μg√Hz.

13 . A contact microphone device comprising:

a vacuum casing; and

the out-of-plane differential accelerometer of claim 12 contained in the vacuum casing;

wherein the out-of-plane differential accelerometer has a frequency response ranging from DC to 10,000 Hz with relatively constant sensitivity.

14 . The contact microphone device of claim 13 , wherein the out-of-plane differential accelerometer has a sensitivity of better than 10 μg√Hz.

15 . The contact microphone device of claim 13 , wherein the out-of-plane differential accelerometer has a sensitivity of better than 100 μg√Hz.

16 . A method comprising:

capturing, with an out-of-plane differential accelerometer, vibrations emanating from a person;

wherein the out-of-plane differential accelerometer comprises:

a suspended proof mass; and

a sensing electrode separated from the suspended proof mass by a nano

sensing gap; and

wherein the out-of-plane differential accelerometer:

has out-of-plane sensitivity and micro-g resolution;

is configured to sense frequencies in both:

a range of from DC to 20 Hz resultant from tilt and/or motion; and

a range of from 20 Hz to 10 k Hz resultant from vibration and/or acoustics; and

has a resonant frequency of greater than 10 k Hz.

17 . The method of claim 16 further comprising:

placing the out-of-plane differential accelerometer upon at least one of skin of the person or a fabric contacting skin of the person.

18 . The method of claim 17 , wherein the out-of-plane differential accelerometer is disposed within at least one of a stethoscope, a wristwatch, a necklace, a wearable strap, a patch, or a sensor.

19 . A method of localizing sounds in a patient comprising:

placing two or more out-of-plane differential accelerometers upon a patient;

capturing vibrations, with at least one of the out-of-plane differential accelerometers, emanating from the patient; and

determining a source of the vibrations by calculating a vibration acceleration level at least one of the out-of-plane differential accelerometers capturing vibrations;

wherein each out-of-plane differential accelerometer comprises:

a suspended proof mass; and

a sensing electrode separated from the suspended proof mass by a nano sensing gap; and

wherein each out-of-plane differential accelerometer:

has out-of-plane sensitivity and micro-g resolution;

is configured to sense frequencies in both:

a range of from DC to 20 Hz resultant from tilt and/or motion; and

a range of from 20 Hz to 10 k Hz resultant from vibration and/or acoustics; and

has a resonant frequency of greater than 10 k Hz.

20 . The method of claim 19 , wherein:

capturing comprises capturing wideband cardio- and pulmonary-induced vibrations from chest wall movements in an infrasonic range of from DC to 20 Hz; and

the out-of-plane sensitivity of the out-of-plane differential accelerometers enable mounting and placement of the out-of-plane differential accelerometers onto skin of the patient as the out-of-plane differential accelerometers have unidirectional sensitivity to sounds emanating from the patient and relatively orthogonal to a surface of the skin.

21 . The method of claim 20 , wherein:

one or more of the out-of-plane differential accelerometers further comprise:

a substrate;

a torsional tether attached to the substrate; and

one or more additional sensing electrodes;

wherein:

the suspended proof mass comprises hinged portions rotatable about the torsional tether and is configured to move out-of-plane of the substrate;

each sensing electrode is separated from the hinged portions of the suspended proof mass by a nano capacitive gap;

the hinged portions of the proof mass are each substantially thicker than the sensing electrodes; and

the hinged portions of the proof mass are mirror symmetric; and

each out-of-plane differential accelerometer:

has an operational bandwidth ranging from DC to 10,000 Hz determined by a tunable resonant frequency of greater than 10 k Hz of the respective out-of-plane differential accelerometer, the resonant frequency being tunable via adjustment of a width of one or more of the nano capacitive gaps;

is hermetically-sealed and configured to maintain a vacuum environment of smaller than or equal to 50 Torr;

is configured to sense frequencies in both:

a range of from DC to 20 Hz resultant from tilt and/or motion; and

a range of from 20 Hz to 10 k Hz resultant from vibration and/or acoustics; and

has a vibration acceleration sensitivity of better than 100 μg√Hz.

Assignments (1)

Continuity (3)

References Cited (30)