Piezoelectric voice accelerometer with back cavity air pressure coupling and multiple resonance peaks

Patent metadata

Field	Value
Publication number	US-12568328-B2
Application number	US-202318470876-A
Country	US
Kind code	B2
Filing date	Sep 20, 2023
Priority date	Sep 20, 2023
Publication date	Mar 3, 2026
Grant date	Mar 3, 2026

Abstract

Systems and techniques are provided for detecting bone-conducted sound. A voice accelerometer can include a substrate and a plurality of sensing elements associated with a plurality of frequency bands. Each frequency band can be associated with one or more sensing elements of the plurality of sensing elements having a respective resonance frequency within the frequency band. The voice accelerometer can include a back cavity enclosed by the plurality of sensing elements and the substrate. Each respective sensing element of the plurality of sensing elements can be configured to vibrate in response to a first force corresponding to a bone-conducted sound wave coupled into the voice accelerometer, and a second force corresponding to a back cavity pressure coupling between the plurality of sensing elements, the back cavity pressure coupling based on respective vibration of each sensing element of the plurality of sensing elements.

First claim

What is claimed is:

1 . A voice accelerometer for detecting bone-conducted sound within a plurality of frequency bands, comprising:
a substrate; a plurality of sensing elements associated with the plurality of frequency bands, wherein each respective frequency band of the plurality of frequency bands is associated with a corresponding one or more sensing elements of the plurality of sensing elements, each of the corresponding one or more sensing elements being associated with a respective resonance frequency within a respective frequency band, and wherein each respective sensing element of the plurality of sensing elements is configured to generate a respective output signal corresponding to vibration of the respective sensing element; and a back cavity enclosed by the plurality of sensing elements and the substrate, wherein a volume of the back cavity extends between the plurality of sensing elements and the substrate, and wherein each respective sensing element of the plurality of sensing elements is configured to vibrate in response to:
a first force corresponding to a bone-conducted sound wave coupled into the voice accelerometer; and
a second force corresponding to a back cavity pressure coupling between the plurality of sensing elements, the back cavity pressure coupling based on respective vibration of each sensing element of the plurality of sensing elements,
wherein the respective output signals are combined based on a wiring configuration between the plurality of sensing elements and an Application-Specific Integrated Circuit (ASIC) to generate a combined signal, wherein the wiring configuration corresponds to a combined signal having a configured capacitance value for an optimal signal-to-noise ratio (SNR) with the ASIC.

2 . The voice accelerometer of claim 1 , wherein the second force is a pressure force corresponding to a change in the volume of the back cavity.

3 . The voice accelerometer of claim 2 , wherein the change in the volume of the back cavity is based on the plurality of sensing elements vibrating in response to the bone-conducted sound wave.

4 . The voice accelerometer of claim 2 , wherein the change in the volume of the back cavity is proportional to an effective area of each sensing element of the plurality of sensing elements and a displacement of each sensing element of the plurality of sensing elements in response to the bone-conducted sound wave.

5 . The voice accelerometer of claim 2 , wherein:
the change in the volume of the back cavity is based on the plurality of sensing elements oscillating in response to the bone-conducted sound wave; and the back cavity pressure coupling is based on the change in the volume of the back cavity and a back cavity airflow through respective gaps between adjacent sensing elements of the plurality of sensing elements.

6 . The voice accelerometer of claim 5 , wherein the second force is a damping force associated with a damping factor corresponding to the volume of the back cavity and the back cavity airflow through the respective gaps.

7 . The voice accelerometer of claim 1 , wherein the back cavity is enclosed by the plurality of sensing elements based on a respective separation distance between adjacent sensing elements of the plurality of sensing elements being less than a threshold value.

8 . The voice accelerometer of claim 1 , wherein the back cavity pressure coupling between the plurality of sensing elements is based on a respective separation distance between adjacent sensing elements of the plurality of sensing elements being less than a threshold value.

9 . The voice accelerometer of claim 8 , wherein the back cavity pressure coupling between the plurality of sensing elements is based on an instantaneous pressure differential across the plurality of sensing elements.

10 . The voice accelerometer of claim 9 , wherein the instantaneous pressure differential is a pressure difference between a back cavity pressure associated with the back cavity and a front cavity pressure associated with a front cavity of the voice accelerometer.

11 . The voice accelerometer of claim 10 , wherein the front cavity is located opposite from the back cavity, and wherein the plurality of sensing elements are located between the back cavity and the front cavity.

12 . The voice accelerometer of claim 10 , wherein the front cavity pressure is one or more of an atmospheric pressure or a static pressure.

13 . The voice accelerometer of claim 10 , wherein the back cavity pressure is a dynamic pressure corresponding to a change in the volume of the back cavity, and wherein the change in the volume of the back cavity is based on oscillation of the plurality of sensing elements between the back cavity and the front cavity.

14 . The voice accelerometer of claim 1 , wherein the plurality of sensing elements comprises a plurality of cantilevers associated with the back cavity.

15 . The voice accelerometer of claim 14 , wherein the plurality of cantilevers are piezoelectric microelectromechanical systems (MEMS) cantilevers.

16 . The voice accelerometer of claim 14 , wherein each respective cantilever of the plurality of cantilevers is coupled at a first distal end to the substrate and extends from the substrate into an empty volume of the back cavity.

17 . The voice accelerometer of claim 14 , wherein the plurality of cantilevers are configured to implement a piezoelectric accelerometer for detecting bone-conducted sound within the plurality of frequency bands.

18 . The voice accelerometer of claim 17 , wherein each respective frequency band of the plurality of frequency bands is associated with one or more cantilevers tuned to a respective resonance frequency corresponding to each respective frequency band.

19 . The voice accelerometer of claim 1 , wherein:
a first subset of sensing elements included in the plurality of sensing elements is associated with a first frequency band of the plurality of frequency bands, and wherein each sensing element of the first subset is associated with a respective resonance frequency within the first frequency band; and a second subset of sensing elements included in the plurality of sensing elements is associated with a second frequency band of the plurality of frequency bands, and wherein each sensing element of the second subset is associated with a respective resonance frequency within the second frequency band.

20 . The voice accelerometer of claim 1 , wherein each respective sensing element of the plurality of sensing elements includes:
a first longitudinal face perpendicular to a direction of vibration of the respective sensing element, the first longitudinal face located within the volume of the back cavity; and a second longitudinal face opposite the first longitudinal face, the second longitudinal face located within a volume of a front cavity enclosed by a housing of the voice accelerometer.

21 . The voice accelerometer of claim 20 , wherein at least one sensing element of the plurality of sensing elements includes a respective aperture extending through the first longitudinal face and the second longitudinal face, the respective aperture including a first opening within the volume of the back cavity and a second opening within the volume of the front cavity.

22 . The voice accelerometer of claim 21 , wherein the back cavity pressure coupling between the plurality of sensing elements is based on back cavity airflow between the back cavity and the f

Assignees

• Qualcomm Inc

Inventors

• Xue Shuwan
• Choi Jong Soo
• Littrell Robert John

Classifications

• H04R2201/003

  Mems transducers or their use · CPC title

• H04R17/10

  Resonant transducers, i.e. adapted to produce maximum output at a predetermined frequency · CPC title

• H04R17/02

  Microphones · CPC title

• H04R1/26

  Spatial arrangements of separate transducers responsive to two or more frequency ranges · CPC title

• H04R1/08

  Mouthpieces; {Microphones;} Attachments therefor · CPC title