Elastomeric dielectric polymer film sonic actuator

• US 6,343,129 B1
• Filed: 07/19/1999
• Issued: 01/29/2002
• Est. Priority Date: 02/07/1997
• Status: Expired due to Term

• Current Assignee: SRI International, Inc.
• Original Assignee: SRI International, Inc.
• Inventors: Pelrine, Ronald E., Kornbluh, Roy D., Eckerle, Joseph S.
• Primary Examiner(s): LE, HUYEN D
• Application Number:
  US09/356,801
• Time in Patent Office: 925 Days
• Field of Search: 381/174, 381/191, 381/113, 381/116, 381/190, 307/400, 367/170, 367/181
• US Class Current: 381/191
• CPC Class Codes: F02G 2243/52 acoustic
• CPC Class Codes: F04B 35/045 using solenoids
• CPC Class Codes: F04B 43/043 Micropumps
• CPC Class Codes: H04R 17/005 using a piezoelectric polymer
• CPC Class Codes: H04R 17/08 signals being recorded or played back by vibration of a stylus in two orthogonal directions simultaneously
• 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: H04R 2499/13 Acoustic transducers and sound field adaptation in vehicles
• CPC Class Codes: H04R 5/02 Spatial or constructional arrangements of loudspeakers

Abstract

A sonic actuator including a multi-layer membrane having an elastomeric dielectric polymer layer with a first surface and a second surface, a first compliant electrode layer contacting the first surface of the polymer layer, and a second compliant electrode layer contacting the second surface of the polymer layer. The actuator further includes a support structure in contact with the sonic actuator film. Preferably, the dielectric polymer is selected from the group consisting essentially of silicone, polyurethane fluorosilicone, fluoroelastomer, natural rubber, polybutadiene, nitrile rubber, isoprene, and ethylene propylene diene. Also preferably, the compliant electrode layer is made from the group consisting essentially of graphite, carbon, and conductive polymers. The support structure can take the form of grid having a number of circular apertures. When a voltage is applied to the electrodes, portions of the film held at the aperture of the support structure can bulge due to the electrostriction phenomenon. The resultant “bubbles” can be driven to generate sonic vibrations, or can be used to create a variable surface for airflow control.

Claims

1. A sonic actuator film comprising:

a multi-layer membrane including

an elastomeric dielectric polymer layer having a first surface and a second surface;

a first compliant electrode layer contacting said first surface; and

a second compliant electrode layer contacting said second surface;

a square root driver coupled to said first compliant electrode and to said second compliant electrode, wherein said square root driver includes a summer adding a low power input signal to an offset voltage and a square root generator coupled to an output of said summer;

a filter coupled to an output of said square root generator, and

a support structure in contact with said sonic actuator film.

2. A sonic actuator as recited in claim 1 further comprising an amplifier coupled to an output of said filter to provide a signal to drive said multi-layer membrane.