Electroactive polymer transducers biased for optimal output

• US 8,072,121 B2
• Filed: 06/29/2009
• Issued: 12/06/2011
• Est. Priority Date: 12/29/2006
• Status: Active Grant

• Current Assignee: Parker-Hannifin Corporation
• Original Assignee: Bayer Materialscience AG (Covestro AG)
• Inventors: Heim, Jonathan R., Feldman, Randall Mark
• Primary Examiner(s): Budd, Mark
• Application Number:
  US12/494,071
• Publication Number:
  US 20100102677A1
• Time in Patent Office: 890 Days
• Field of Search: 310/328, 310/800
• US Class Current: 310/330
• CPC Class Codes: B06B 1/02 making use of electrical energy B06B1/18, B06B1/20 take precedence
• CPC Class Codes: B06B 1/0292 Electrostatic transducers, e.g. electret-type
• CPC Class Codes: F04B 19/006 Micropumps F04B43/043 and F04B43/095 take precedence
• CPC Class Codes: F04B 43/043 Micropumps
• CPC Class Codes: G02B 7/08 adapted to co-operate with a remote control mechanism
• CPC Class Codes: G06F 3/016 Input arrangements with force or tactile feedback as computer generated output to the user
• CPC Class Codes: H10N 30/206 using only longitudinal or thickness displacement, e.g. d33 or d31 type devices
• CPC Class Codes: H10N 30/857 Macromolecular compositions
• CPC Class Codes: H10N 30/886 Mechanical prestressing means, e.g. springs springs in general F16F1/00
• CPC Class Codes: Y10S 310/80 Piezoelectric polymers, e.g. PVDF

Abstract

Electroactive polymer transducers are disclosed. They are biased in a manner that provides for increased force and/or stroke output, thereby offering improved work potential and power output capacity. The biasing may offer additional or alternate functional advantage in terms of matching transducer performance with a given application such as a normally-closed valve. The improved biasing (including increased output biasing) may utilize negative spring rate biasing and/or a combination of negative or zero-rate biasing with positive rate biasing to achieve the desired ends.

Claims

1. A transducer assembly comprising electroactive polymer material and at least one biasing element, the improvement consisting of at least one biasing element set to provide a negative rate bias on the electroactive polymer material.

2. The transducer assembly of claim 1, further comprising at least one other biasing element set to provide a positive rate bias on the electroactive polymer material.

3. The transducer assembly of claim 1, wherein the at least one negative rate biasing element comprises any of a coil spring, leaf spring, a magnetic material, air pressure, fluid pressure or a combination thereof.

4. The transducer assembly of claim 3, wherein the at least one biasing element comprises a first magnetic element in contact with the electroactive polymer material and a second magnetic element at fixed position a distance form the first magnetic element.

5. The transducer assembly of claim 1, comprising a plurality of negative rate biasing elements in the form of leaf springs arranged in a clover configuration.

6. The transducer assembly of claim 1 adapted to operate as either an actuator, a generator or a sensor.

7. The transducer assembly of claim 1, wherein the transducer assembly forms part of a lens positioner, a valve mechanism, a pump, a light reflector, a speaker, a vibrator, a haptic feedback device or a force feedback device.

8. A transducer assembly comprising electroactive polymer material and a positive rate biasing element, the improvement consisting of at least one additional biasing element set to provide a negative or substantially zero rate bias on the electroactive polymer material.

9. A transducer assembly comprising electroactive polymer material and at least one biasing element, the improvement consisting of at least one biasing element having a bi-stable configuration to enable the transducer assembly to actuate in opposite directions without further biasing.

10. The transducer assembly of claim 9, wherein the electroactive polymer material forms at least a portion of a diaphragm, the transducer assembly further comprising a capping structure associated with the electroactive polymer material to form a frustum-style assembly.