Electroactive polymer device

• US 8,093,783 B2
• Filed: 05/24/2010
• Issued: 01/10/2012
• Est. Priority Date: 05/22/2001
• Status: Expired due to Term

• Current Assignee: SRI International, Inc.
• Original Assignee: SRI International, Inc.
• Inventors: Rosenthal, Marcus A., Pei, Qibing, Bonwit, Neville A.
• Primary Examiner(s): Budd, Mark
• Application Number:
  US12/786,010
• Publication Number:
  US 20110025170A1
• Time in Patent Office: 596 Days
• Field of Search: 310330-332, 310/369, 310/800
• US Class Current: 310/328
• CPC Class Codes: A61M 2205/0283 Electro-active polymers [EAP]
• CPC Class Codes: A61M 5/142 Pressure infusion, e.g. using pumps
• CPC Class Codes: A61M 5/14276 specially adapted for implantation
• CPC Class Codes: F01L 1/46 Component parts, details, or accessories, not provided for in preceding subgroups
• CPC Class Codes: F01L 2301/00 Using particular materials
• CPC Class Codes: F01L 7/02 with cylindrical, sleeve, or part-annularly shaped valves of disc type F01L7/06; of conical type F01L7/08
• CPC Class Codes: F01L 9/20 by electric means
• 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 43/043 Micropumps
• CPC Class Codes: H02N 11/006 Motors
• CPC Class Codes: H04R 19/00 Electrostatic transducers
• CPC Class Codes: H04R 2307/029 Diaphragms comprising fibres
• CPC Class Codes: H10N 30/05 Manufacture of multilayered piezoelectric or electrostrictive devices, or parts thereof, e.g. by stacking piezoelectric bodies and electrodes
• CPC Class Codes: H10N 30/098 Forming organic materials
• CPC Class Codes: H10N 30/2046 adapted for multi-directional bending displacement
• CPC Class Codes: H10N 30/206 using only longitudinal or thickness displacement, e.g. d33 or d31 type devices
• CPC Class Codes: H10N 30/302 Sensors
• CPC Class Codes: H10N 30/506 having a cylindrical shape and having stacking in the radial direction, e.g. coaxial or spiral type rolls
• CPC Class Codes: H10N 30/802 Circuitry or processes for operating piezoelectric or electrostrictive devices not otherwise provided for, e.g. drive circuits
• CPC Class Codes: Y10S 310/80 Piezoelectric polymers, e.g. PVDF
• CPC Class Codes: Y10T 29/42 : Piezoelectric device making
• CPC Class Codes: Y10T 29/43 : Electric condenser making
• CPC Class Codes: Y10T 29/49117 : Conductor or circuit manufacturing
• CPC Class Codes: Y10T 29/49124 : On flat or curved insulated base, e.g., printed circuit, etc.
• CPC Class Codes: Y10T 29/49128 : Assembling formed circuit to base
• CPC Class Codes: Y10T 29/49139 : by inserting component lead or terminal into base aperture
• CPC Class Codes: Y10T 29/49155 : Manufacturing circuit on or in base

Abstract

The invention describes rolled electroactive polymer devices. The invention also describes employment of these devices in a wide array of applications and methods for their fabrication. A rolled electroactive polymer device converts between electrical and mechanical energy; and includes a rolled electroactive polymer and at least two electrodes to provide the mechanical/electrical energy conversion. Prestrain is typically applied to the polymer. In one embodiment, a rolled electroactive polymer device employs a mechanism, such as a spring, that provides a force to prestrain the polymer. Since prestrain improves mechanical/electrical energy conversion for many electroactive polymers, the mechanism thus improves performance of the rolled electroactive polymer device.

Claims

1. A polymer roll transducer comprising:

an electroactive polymer roll having at least two layers of an electroactive polymer, wherein the electroactive polymer has an elastic modulus below 100 Mpa;

one or more electrodes disposed on the electroactive polymer roll; and

a securing means for securing the electroactive polymer roll to maintain a rolled configuration, wherein the securing means comprises an end cap.

2. The polymer roll transducer of claim 1, wherein the polymer roll transducer actuates linearly in response to an electric potential applied to the one or more electrodes.

3. The polymer roll transducer of claim 1, wherein the electroactive polymer roll is cut into a plurality of strands.

4. The polymer roll transducer of claim 3, wherein the strands are secured at three or more points to the securing means.

5. The polymer roll transducer of claim 1, wherein the electroactive polymer is capable of converting between mechanical and electrical energy.

6. A device for converting between electrical and mechanical energy, the device comprising:

a polymer roll transducer comprising a) an electroactive polymer including at least one active area and b) at least two electrodes in electrical communication with the active area wherein at least a portion of the electroactive polymer is wrapped upon itself to form a roll; and

at least one mechanical linkage coupled to the polymer roll transducer for securing the electroactive polymer roll to maintain a rolled configuration.

7. The device of claim 6, further comprising at least one support member coupled to the polymer roll transducer for providing at least one of i) a force that strains at least a portion of the polymer, ii) a force for controlling bending in the polymer roll transducer and iii) combinations thereof.

8. The device of claim 7, where the mechanical linkage is coupled to both the at least one support member and to the polymer roll member for allowing a force or a moment generated in a first portion of the polymer roll transducer to be communicated to a second portion of the polymer roll transducer such that the device provides precisely controlled angular movements, angular output and/or angular stiffness control.

9. The device of claim 7, where the mechanical linkage comprises an end cap coupled to the support member in a manner allowing movement of the end cap in one or more directions.

10. The device of claim 9, wherein the end cap is rotationally coupled to the support member.

11. The device of claim 9, wherein an actuation of the active area of the electroactive polymer provides a force to moves the end cap in the one or more directions.

12. The device of claim 9, wherein a non-active area of the electroactive polymer provides a force to the move the end cap in the one or more directions.

13. The device of claim 9, further comprising a sensor for determining a position of the end cap.

14. The device of claim 7, further comprising a base rigidly coupled to the support member.

15. The device of claim 14, wherein the electroactive polymer is attached to the base.

16. The device of claim 14, wherein a plurality of mechanical linkages are rotationally coupled to a support member.

17. The device of claim 16, wherein the mechanical linkages and the support member are disposed within a hollow portion of the roll.

18. The device of claim 16, wherein the mechanical linkages are disk shaped.

19. The device of claim 16, wherein tensile forces, stored in a number of portions of the electroactive polymer, are transferred via the plurality of mechanical linkages to other portions of the electroactive polymer.

20. The device of claim 6, where at least one active area of the electroactive polymer comprises at least one sensor.

21. The device of claim 20, wherein the sensor is arranged for measuring or determining one or more of an angular position, an angular velocity or an angular position of more components of the device.

22. The device of claim 20, wherein the sensor is for measuring a strain of a component in the device.

23. The device of claim 6, wherein the roll is cut in one or more places for limiting a propagation of a force or a moment from a first portion of the roll to a second portion of the roll.

24. The device of claim 6, wherein the device includes a joint for coupling a first component of the device to a second component of the device and for allowing a relative rotation between the two components.

25. The device of claim 24, wherein the first component is a first support member and the second component is a second support member.

26. The device of claim 24, wherein the first component is the support member and the second component is the mechanical linkage.

27. The device of claim 6, wherein the mechanical linkage is a spring.

28. The device of claim 7, the support member comprises a first component rotationally coupled to a second component and the transducer is arranged in a manner to move the first component and the second component to different angular position relative to one another.

29. The device of claim 6, wherein the electroactive polymer is attached at one or more points to create moment arms of varying lengths about a rotational coupling point in the device wherein each moment arm is a distance between a force generated in the electroactive polymer and the rotational coupling point.

30. The device of claim 7, wherein at least a portion of the support member or the mechanical linkage is disposed in a hollow central part of the roll.

31. The device of claim 6, wherein the electroactive polymer is a dielectric elastomer.

32. The device of claim 6, wherein the electroactive polymer has an elastic modulus at most about 100 MPa.

33. The device of claim 6, wherein the support member comprises of plurality of telescoping tubes.

34. A device for converting between electrical and mechanical energy, the device comprising:

an electroactive polymer configured in a tube shape to form an electroactive polymer roll transducer, the electroactive polymer including at least one active area and at least two electrodes in electrical communication with the active area; and

at least one mechanical linkage coupled to the polymer roll transducer for securing the electroactive polymer roll.