Push-pull electret transducer with controlled restoring force for low frequency microphones and energy harvesting

Patent metadata

Field	Value
Publication number	US-11228844-B2
Application number	US-201816614086-A
Country	US
Kind code	B2
Filing date	May 18, 2018
Priority date	May 18, 2017
Publication date	Jan 18, 2022
Grant date	Jan 18, 2022

Abstract

Provided is an energy harvesting system, including: a first electrode; a second electrode; a non-metalized mono-charged electret diaphragm disposed between the first and second electrodes; a base; a spring extending between the base and the electret diaphragm; and a rod in communication with the electret diaphragm and for manipulating a position of the electret diaphragm relative to the first and second electrodes.

First claim

What is claimed is:

1. A push-pull electret transducer, comprising:
a first electrode;
a second electrode;
a non-metalized mono-charged electret diaphragm disposed between the first and second electrodes;
at least one spring, wherein the at least one spring contacts the electret diaphragm; and
a supporting frame counterbalance, wherein the supporting frame counterbalance contacts the electret diaphragm and wherein the at least one spring opposes a force applied against the electret diaphragm by the frame counterbalance.

2. The push-pull electret transducer of claim 1 , wherein the electret diaphragm is disposed between the supporting frame counterbalance and the at least one spring.

3. The push-pull electret transducer of claim 2 , wherein a change in pressure on the supporting frame counterbalance causes the electret diaphragm to move between the first and second electrodes.

4. The push-pull electret transducer of claim 2 , wherein movement of the electret diaphragm results in a charge rearrangement on the first and second electrodes.

5. The push-pull electret transducer of claim 1 , wherein the mono-charged diaphragm comprises a polymer.

6. The push-pull electret transducer of claim 5 , wherein the polymer comprises a fluoropolymer.

7. The push-pull electret transducer of claim 6 , wherein the fluoropolymer comprises fluorinated ethylene propylene (FEP).

8. The push-pull electret transducer of claim 6 , wherein the fluoropolymer comprises polytetrafluoroethylene (PTFE).

9. The push-pull electret transducer of claim 1 , wherein a static position of the electret diaphragm is balanced between the first and second electrodes such that push-pull electret transducer is configured as a microphone.

10. The push-pull electret transducer of claim 1 , wherein a variable restoring force supports the mono-charged electret diaphragm between the first and second electrodes.

11. The push-pull electret transducer of claim 10 , configured as a microphone.

12. The push-pull electret transducer of claim 11 , configured as a microphone for use in water.

13. The push-pull electret transducer of claim 11 having a sensitivity in the range of from about 10 to 100 mV/Pa.

14. The push-pull electret transducer of claim 1 , wherein the mono-charged electret diaphragm has an asymmetric static position.

Assignees

• Univ Johns Hopkins
• Univ Darmstadt Tech

Inventors

• West James E
• Ren Kailang
• Eisape Adebayo
• Sessler Gerhard
• Erturun Ugur

Classifications

• H04R19/016 Primary

  for microphones · CPC title

• H04R1/406

  microphones · CPC title

• H04R19/04

  Microphones (H04R19/01 takes precedence) · CPC title

• H04R7/04

  Plane diaphragms · CPC title

• H04R31/003

  for diaphragms or their outer suspension · CPC title