Compliant electroactive polymer transducers for sonic applications

• US 7,898,159 B2
• Filed: 09/22/2009
• Issued: 03/01/2011
• Est. Priority Date: 07/20/1999
• Status: Expired due to Fees

• Current Assignee: SRI International, Inc.
• Original Assignee: SRI International, Inc.
• Inventors: Heydt, Richard P., Eckerle, Joseph S., Pelrine, Ronald E., Bonwit, Neville A., Kornbluh, Roy D.
• Primary Examiner(s): Dougherty; Thomas M
• Application Number:
  US12/564,793
• Publication Number:
  US 20100013356A1
• Time in Patent Office: 525 Days
• Field of Search: 310/317, 310/328, 310/330, 310/800
• US Class Current: 310/317
• CPC Class Codes: H04R 19/02 Loudspeakers H04R19/01 takes precedence
• CPC Class Codes: Y10S 310/80 Piezoelectric polymers, e.g. PVDF

Abstract

Described herein are compliant electroactive polymer transducers for use in acoustic applications. A compliant electroactive polymer transducer includes a compliant electroactive polymer at least two electrodes. For sound production, circuitry in electrical communication with the transducer electrodes is configured to apply a driving signal that causes the electroactive polymer to deflect in the acoustic range.

Claims

1. A sonic device comprising:

an electroactive polymer transducer including a portion of an electroactive polymer and a first electrode in contact with the portion and a second electrode in contact with the portion, wherein the electroactive polymer transducer is arranged in a manner which causes the portion to deflect in response to a change in electric field that is applied via at least one of the first electrode and the second electrode,

and wherein the electroactive polymer has an elastic modulus less than about 100 MPa;

and a circuit in electrical communication with the first electrode and the second electrode and configured to provide an actuation signal to the at least one of the first electrode and second electrode, wherein the actuation signal causes the electroactive polymer transducer to deflect at a frequency less than about 50 kHz.

2. The sonic device of claim 1 further comprising a biasing mechanism that is configured to position the portion of the electroactive polymer in a bias position from which the portion deflects.

3. The sonic device of claim 1 wherein the electroactive polymer transducer includes a) a planar shape when a biasing mechanism does not position the portion in a bias position and b) a non-planar shape when the portion is in the bias position.

4. The sonic device of claim 1 wherein a biasing mechanism includes a second electroactive polymer transducer, including a second electroactive polymer and at least two electrodes coupled to the second electroactive polymer.

5. The sonic device of claim 1 wherein the electroactive polymer is an elastomeric dielectric polymer.

6. A sonic device comprising:

an electroactive polymer transducer including a portion of an electroactive polymer and a first electrode in contact with the portion and a second electrode in contact with the portion, wherein the electroactive polymer transducer is arranged in a manner which causes the portion to deflect in response to a change in electric field that is applied via at least one of the first electrode and the second electrode,

and wherein the electroactive polymer has an elastic modulus less than about 100 MPa;

and a circuit in electrical communication with the first electrode and the second electrode and configured to provide an actuation signal to the at least one of the first electrode and second electrode, wherein the actuation signal causes the electroactive polymer transducer to deflect at a frequency less than about 50 kHz,

and wherein a portion of the electroactive polymer is capable of a planar strain of greater than 25% between a first position of the portion with a first area and a second position of the portion with a second area.