Pressure sensor and system for measuring pressure

Patent metadata

Field	Value
Publication number	US-11415474-B2
Application number	US-202016901842-A
Country	US
Kind code	B2
Filing date	Jun 15, 2020
Priority date	Jun 15, 2020
Publication date	Aug 16, 2022
Grant date	Aug 16, 2022

Abstract

A pressure sensor includes an input terminal configured to receive an electrical input signal and an output terminal configured to provide an electrical output signal in response to the electrical input signal. The pressure sensor also includes an acousto-mechanical diaphragm and an electrically conductive element formed on the acousto-mechanical diaphragm. The pressure sensor further includes a distributed element filter configured to capacitively couple the input terminal to the output terminal. The distributed element filter is spaced from the electrically conductive element by an air gap. The air gap changes in response to a deflection of the acousto-mechanical diaphragm caused by a change in pressure on the acousto-mechanical diaphragm.

First claim

What is claimed is:

1. A pressure sensor, comprising:
an input terminal configured to receive an electrical input signal;
an output terminal configured to provide an electrical output signal in response to the electrical input signal;
an acousto-mechanical diaphragm;
an electrically conductive element formed on the acousto-mechanical diaphragm;
a distributed element filter configured to capacitively couple the input terminal to the output terminal, wherein the distributed element filter is spaced from the electrically conductive element by an air gap, and wherein the air gap changes in response to a deflection of the acousto-mechanical diaphragm caused by a change in pressure on the acousto-mechanical diaphragm;
a first die, wherein the acousto-mechanical diaphragm is formed in the first die;
a second die, wherein the distributed element filter is formed on a first side of the second die, and wherein the distributed element filter faces the electrically conductive element when the first die is attached to the second die;
a cavity defined between the acousto-mechanical diaphragm and the distributed element filter when the first die is attached to the second die; and
a ground plane formed on a second side of the second die opposite to the first side.

2. The pressure sensor of claim 1 , wherein an amplitude of the electrical output signal from the pressure sensor changes from a nominal amplitude in response to the deflection of the acousto-mechanical diaphragm, at least one of a dynamic pressure or a static pressure is measured based on a change in the amplitude of the electrical output signal from the nominal amplitude, and wherein the electrical output signal is at the nominal amplitude when there is no deflection of the acousto-mechanical diaphragm.

3. The pressure sensor of claim 1 , wherein the air gap is configured to capacitively couple the electrically conductive element to the distributed element filter, and wherein the distributed element filter has a nominal resonant frequency when there is no change to the air gap, and wherein a change in a capacitance between the electrically conductive element and the distributed element filter occurs in response to the deflection of the acousto-mechanical diaphragm and a resonant frequency of the of the distributed element filter changes from the nominal resonant frequency in response to the change in the capacitance.

4. The pressure sensor of claim 3 , wherein an amplitude of the electrical output signal from the pressure sensor changes in response to a change in the resonant frequency of the distributed element filter caused by the change in pressure on the acousto-mechanical diaphragm, and wherein the amplitude of the electrical output signal is used to measure a dynamic pressure or a static pressure in response to the electrical input signal being received by the pressure sensor.

5. The pressure sensor of claim 1 , wherein the input terminal is configured to electrically connect the pressure sensor to a signal generator to receive the electrical input signal, and the output terminal is configured to electrically connect the pressure sensor to a pressure measurement device configured to measure at least one of a dynamic pressure or a static pressure.

6. The pressure sensor of claim 1 , wherein the distributed element filter comprises a plurality of electrically conductive components, each electrically conductive component comprising:
a first elongated member;
a second elongated member extending parallel to the first elongated member at a first preset spacing between the first elongated member and the second elongated member; and
a base member connecting one end of the first elongated member to an adjacent end of the second elongated member, wherein the electrically conductive components are disposed parallel to one another and at a second preset spacing from one another with the base members being alternately placed on opposite sides of the distributed element filter.

7. The pressure sensor of claim 1 , wherein the first die, the second die, the electrically conductive element and the distributed element filter each comprise a material to allow the pressure sensor to operate at a temperature at or above about 600 degrees centigrade.

8. The pressure sensor of claim 1 , wherein the acousto-mechanical diaphragm comprises a predetermined thickness and a preset size when formed in the first die, and the first die comprises a material having a selected elastic modulus, and wherein an acoustic resonant frequency of the pressure sensor is determined based on at least one of the predetermined thickness of the acousto-mechanical diaphragm, the preset size of the acousto-mechanical diaphragm, or the selected elastic modulus of the material of the acousto-mechanical diaphragm.

9. The pressure sensor of claim 1 , further comprising a vent channel between the cavity and an environment outside of the pressure sensor, wherein the vent channel provides a pressure equilibrium on each side of the acousto-mechanical diaphragm for selectively sensing or measuring dynamic pressure by the pressure sensor.

10. The pressure sensor of claim 9 , wherein the air gap comprises a selected width and wherein an amount of the dynamic pressure is measured based on an amount of deflection of the acousto-mechanical diaphragm into the air gap caused by the change in pressure on the acousto-mechanical diaphragm.

11. The pressure sensor of claim 9 , wherein the vent channel is closed or excluded from the pressure sensor to allow deflection of the acousto-mechanical diaphragm in response to static pressure.

12. The pressure sensor of claim 1 , further comprising:
an array of pressure sensors, each pressure sensor being configured to measure a different predetermined acoustic frequency band of acoustic pressure and each pressure sensor comprising:
an acousto-mechanical diaphragm;
an electrically conductive element formed on the acousto-mechanical diaphragm; and
a distributed element filter spaced from the electrically conductive element by an air gap, wherein the acousto-mechanical diaphragm, the electrically conductive element and the distributed element filter are configured to measure a particular predetermined acoustic frequency band of acoustic pressure.

13. The pressure sensor of claim 12 , wherein, for each pressure sensor, the electrically conductive element is capacitively coupled to the distributed element filter, and the acousto-mechanical diaphragm is configured to allow the air gap to change in response to the change in pressure on the acousto-mechanical diaphragm, a capacitance of the distributed element filter changes in response to the change in the air gap and a resonant frequency of the distributed element filter changes in response to the change in capacitance of the distributed element filter to measure the particular predetermined acoustic frequency band of acoustic pressure.

14. A system for measuring pressure, comprising:
a signal generator;
a pressure sensor configured to sense a change in pressure and to receive an electrical input signal from the signal generator, wherein the pressure sensor comprises:
an acousto-mechanical diaphragm;
an electrically conductive element formed on the acousto-mechanical diaphragm;
a distributed element filter spaced from the electrically conductive element by an air gap, wherein the air gap changes in response to a deflection of the acousto-mechanical diaphragm caused by a change in pressure on the acousto-mechanical diaphragm, and an amplitude of an electrical output signal from the pressure sensor changes from a nominal amplitude in response to the deflecti

Assignees

• Boeing Co

Inventors

• Rogers John E

Classifications

• G01L9/0072 Primary

  using variations in capacitance · CPC title

• G01L9/0044

  Constructional details of non-semiconductive diaphragms · CPC title