Polymeric sensor of vibration and dynamic pressure

• US 3,970,862 A
• Filed: 06/25/1974
• Issued: 07/20/1976
• Est. Priority Date: 06/25/1974
• Status: Expired due to Term

• Current Assignee: the united states of america as represented by the secretary of the navy
• Original Assignee: the united states of america as represented by the secretary of the navy
• Inventors: Edelman, Seymour, Roth, Steven C., Mayo-Wells, John F.
• Primary Examiner(s): Moffitt, James W.
• Application Number:
  US05/477,141
• Time in Patent Office: 756 Days
• Field of Search: 307/88 ET, 179/111 E, 29/25.35, 29/592
• US Class Current: 307/400
• CPC Class Codes: B06B 1/0688 with foil-type piezoelectric elements, e.g. PVDF
• CPC Class Codes: G01L 1/16 using properties of piezoelectric devices
• CPC Class Codes: G01L 23/10 by pressure-sensitive members of the piezoelectric type
• CPC Class Codes: G01L 9/0001 Transmitting or indicating the displacement of elastically deformable gauges by electric, electro-mechanical, magnetic or electro-magnetic means G01L9/0026, G01L9/0033, G01L9/0082, G01L9/0089, G01L9/0091 take precedence
• CPC Class Codes: Y10S 310/80 Piezoelectric polymers, e.g. PVDF
• CPC Class Codes: Y10T 29/42 Piezoelectric device making
• CPC Class Codes: Y10T 29/49002 Electrical device making

Abstract

A transducer, and method for making it, comprising a composite film for sing pressure comprising a pair of film sandwiches, each sandwich comprising a poled polymeric films with metallic film electrodes on opposite surfaces. One electrode does not extend quite to the end of the polymer and is considered the "hot" electrode. Two such transducer film sandwiches are cemented together with the hot electrodes in contact with each other, the center wire from a coaxial cable being in contact with and between them. The outer electrodes are electrically connected to the shield of the cable and the connection is encapsulated.

Claims

1. A polymeric film transducer for sensing dynamic pressure and vibrations comprising:

a first film sandwich comprising a sheet of permanently polarizable polymeric film, one surface being coated with at least one geometrically shaped area of electrically conductive material forming a lead to said geometrically shaped area, the other surface of said polymeric sheet having an electrically conductive coating covering at least the same area as said geometrically shaped area;

a second film sandwich which is a mirror image of the first, said second sandwich being cemented over and in geometrical correspondence with the first, the surface carrying the geometrically shaped films and leads forming the contacting interface, wherein the inactive lead area is in the form of a narrow strip;

electrical connection means making electrical contact with said interfacing coatings in the lead area comprising the center wire of a coaxial cable fitting between the interfacing coatings; and

electrical connection means making electrical contact with both of said outer conductive coatings in the lead area including the metallic shield of said cable and an electrically conductive, flexible, adhesive material extending from the shield to the outer coatings.

2. A transducer as in claim 1, wherein one of said interfacing coatings carries an electrically conductive adhesive dot thereon which is higher than the surrounding surface, the interface electrical connection means being in contact with this dot.

3. A transducer as in claim 1, wherein the electrically conductive coatings are metallic films.

4. A transducer as in claim 1, wherein the interfacing conductive coatings are formed from aluminum and the outer coatings are formed from nickel which is thin enough to be transparent.

5. A transducer as in claim 1, further including means for encapsulating the area of connection covered by said electrically conductive, flexible, adhesive material.

6. A transducer as in claim 5, wherein said electrically conductive, flexible, adhesive material is silver-filled epoxy.

7. A transducer as in claim 5, wherein said encapsulating material is epoxy resin.