Foam pressure sensor

Patent metadata

Field	Value
Publication number	US-10378983-B2
Application number	US-201515326148-A
Country	US
Kind code	B2
Filing date	Jul 13, 2015
Priority date	Jul 14, 2014
Publication date	Aug 13, 2019
Grant date	Aug 13, 2019

Abstract

A pressure sensor includes a first plate ( 102 ), a second plate ( 104 ) and a foam ( 106 ) disposed between the first and second plate. The foam is a polyurethane foam having an average cell size of about 50 to 250 urn and a density of between 5 to 30 lbs/ft3.

First claim

What is claimed is:

1. A hybrid sensor comprising:
a first plate;
a second plate;
a foam disposed between the first and second plate;
wherein the first plate, the second plate and the foam are disposed relative to each other forming a foam capacitor:
a conductor clad piezoelectric film is disposed on a surface of one of the first or second plates forming a piezoelectric sensor;
wherein the piezoelectric sensor has a bandwidth, defined by an intrinsic RC time constant of the piezoelectric sensor, that is larger than a bandwidth of the foam capacitor, providing a hybrid sensor having a high bandwidth impact sensor via the piezoelectric sensor, and a lower bandwidth pressure sensor via the foam capacitor.

2. The hybrid sensor of claim 1 , wherein the foam has a density between 6 to 25 lbs/ft 3 .

3. The hybrid sensor of claim 1 , wherein the foam has a compression set of less than about 10%.

4. The hybrid sensor of claim 1 , wherein the foam has a force-deflection of between about 1-9 psi (7-63 kPa).

5. The hybrid sensor of claim 1 , wherein the plates are metallic.

6. The hybrid sensor of claim 1 , wherein the foam is a polyurethane foam having an average cell size of about 50 to 250 μm and a density of between 5 to 30 lbs/ft 3 .

7. The hybrid sensor of claim 1 , wherein the first plate, the second plate, and the foam, form a foam capacitor, and wherein the foam capacitor and the conductor clad piezoelectric film are electrically connected to provide a common ground between them.

8. The hybrid sensor of claim 7 , wherein the conductor clad piezoelectric film is connected between an analog to digital converter and the common ground.

9. The hybrid sensor of claim 7 , wherein the foam capacitor is connected between a capacitance sensor and the common ground.

Assignees

• Rogers Corp

Inventors

• Shere Aniruddha
• Sprentall Karl E

Classifications

• G01L9/12

  by making use of variations in capacitance {, i.e. electric circuits therefor} · CPC title

• G01L9/0005 Primary

  using variations in capacitance (G01L9/0072 takes precedence) · CPC title

• G01L9/005 Primary

  Non square semiconductive diaphragm · CPC title