Electroactive polymers

• US 7,224,106 B2
• Filed: 01/18/2006
• Issued: 05/29/2007
• Est. Priority Date: 07/20/1999
• Status: Expired due to Term

• Current Assignee: SRI International, Inc.
• Original Assignee: SRI International, Inc.
• Inventors: Pei, Qibing, Pelrine, Ronald E., Kornbluh, Roy D.
• Primary Examiner(s): Dougherty, Thomas M.
• Application Number:
  US11/335,030
• Publication Number:
  US 20060113880A1
• Time in Patent Office: 496 Days
• Field of Search: 310/309, 310/311, 310/328, 310/800
• US Class Current: 310/311
• CPC Class Codes: F02G 1/043 the engine being operated by expansion and contraction of a mass of working gas which is heated and cooled in one of a plurality of constantly communicating expansible chambers, e.g. Stirling cycle type engines
• CPC Class Codes: F02G 2243/52 acoustic
• CPC Class Codes: F04B 35/00 Piston pumps specially adapted for elastic fluids and characterised by the driving means to their working members, or by combination with, or adaptation to, specific driving engines or motors, not otherwise provided for
• CPC Class Codes: F04B 35/045 using solenoids
• CPC Class Codes: F04B 43/043 Micropumps
• CPC Class Codes: F05C 2225/08 Thermoplastics
• CPC Class Codes: F25B 9/14 characterised by the cycle used, e.g. Stirling cycle
• CPC Class Codes: H01G 5/16 using variation of distance between electrodes
• CPC Class Codes: H02N 2/023 Inchworm motors
• CPC Class Codes: H04R 19/02 Loudspeakers H04R19/01 takes precedence
• CPC Class Codes: H04R 23/00 Transducers other than those covered by groups H04R9/00 - H04R21/00 diaphragms for transducers of the distributed-mode type H04R7/045
• CPC Class Codes: H10N 30/098 Forming organic materials
• CPC Class Codes: H10N 30/2042 Cantilevers, i.e. having one fixed end
• CPC Class Codes: H10N 30/206 using only longitudinal or thickness displacement, e.g. d33 or d31 type devices
• CPC Class Codes: H10N 30/30 with mechanical input and electrical output, e.g. functioning as generators or sensors
• CPC Class Codes: H10N 30/308 Membrane type
• CPC Class Codes: H10N 30/857 Macromolecular compositions
• CPC Class Codes: H10N 30/87 Electrodes or interconnections, e.g. leads or terminals
• CPC Class Codes: H10N 30/878 the principal material being non-metallic, e.g. oxide or carbon based
• CPC Class Codes: Y10S 310/80 Piezoelectric polymers, e.g. PVDF
• CPC Class Codes: Y10T 29/49826 : Assembling or joining

Abstract

The present invention relates to transducers, their use and fabrication. The transducers convert between mechanical and electrical energy. Some transducers of the present invention include a pre-strained polymer. The pre-strain improves the conversion between electrical and mechanical energy. The present invention also relates to devices including an electroactive polymer to convert between electrical and mechanical energy. The present invention further relates to compliant electrodes that conform to the shape of a polymer included in a transducer. The present invention provides methods for fabricating electromechanical devices including one or more electroactive polymers.

Claims

1. A transducer for converting between mechanical and electrical energy, the transducer comprising:

at least two electrodes;

a polymer arranged in a manner which causes a portion of the polymer to deflect in response to a change in electric field and/or arranged in a manner which causes a change in electric field in response to deflection of the polymer, wherein the polymer has an elastic modulus at most about 100 MPa; and

a layer laminated to at least a portion of one of the polymer and the at least two electrodes.

2. The transducer of claim 1 wherein the layer distributes mechanical forces across the polymer more uniformly during deflection than mechanical forces produced in the polymer without the layer.

3. The transducer of claim 1 wherein the layer is laminated between the at least two electrodes.

4. The transducer of claim 1 wherein the layer increases breakdown strength of the transducer.

5. The transducer of claim 1 wherein the layer is used to compensate for manufacturing defects in the polymer.

6. The transducer of claim 1 wherein the layer improves a mechanical property of the transducer.

7. The transducer of claim 6 wherein the layer improves stiffness for the transducer.

8. The transducer of claim 7 wherein the layer has a higher stiffness than the polymer.

9. The transducer of claim 1 wherein the layer is an adhesive layer.

10. A transducer for converting between mechanical and electrical energy, the transducer comprising:

at least two electrodes;

a polymer arranged in a manner which causes a portion of the polymer to deflect in response to a change in electric field and/or arranged in a manner which causes a change in electric field in response to deflection of the polymer, wherein the polymer has an elastic modulus at most about 100 MPa; and

a layer mechanically coupled to at least a portion of one of the polymer and the at least two electrodes.

11. The transducer of claim 10 wherein the layer is adhered to the polymer using an adhesive or glue.

12. The transducer of claim 10 wherein the layer distributes mechanical forces across the polymer more uniformly during deflection than mechanical forces produced in the polymer without the layer.

13. The transducer of claim 10 wherein the layer is mechanically coupled between the at least two electrodes.

14. The transducer of claim 10 wherein the layer improves a mechanical property of the transducer.

15. The transducer of claim 14 wherein the layer improves stiffness for the transducer.

16. A transducer for converting between mechanical and electrical energy, the transducer comprising:

at least two electrodes;

a polymer arranged in a manner which causes a portion of the polymer to deflect in response to a change in electric field and/or arranged in a manner which causes a change in electric field in response to deflection of the polymer, wherein the polymer has an elastic modulus at most about 100 MPa; and

a layer mechanically coupled to at least a portion of the polymer and disposed between a first electrode of the at least two electrodes that is configured to electrically communicate with a first surface of the polymer and a second electrode of the at least two electrodes that is configured to electrically communicate with a second surface of the polymer on an opposite side of the polymer relative to the first surface, wherein the layer increases breakdown strength of the transducer.