Source: http://www.google.com/patents/US20080191585?dq=7,136,842
Timestamp: 2014-08-21 07:22:18
Document Index: 67372705

Matched Legal Cases: ['Application No. 60', 'Application No. 60', 'Application No. 60', 'Application No. 60', 'Application No. 60', 'Application No. 60', 'Application No. 60']

Patent US20080191585 - Electroactive polymer electrodes - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign in<nobr>Advanced Patent Search</nobr>PatentsDescribed herein are transducers, their use and fabrication. The transducers convert between mechanical and electrical energy. The present invention further relates to compliant electrodes that conform to the shape of a polymer included in a transducer....http://www.google.com/patents/US20080191585?utm_source=gb-gplus-sharePatent US20080191585 - Electroactive polymer electrodesAdvanced Patent SearchPublication numberUS20080191585 A1Publication typeApplicationApplication numberUS 11/774,918Publication dateAug 14, 2008Filing dateJul 9, 2007Priority dateJul 20, 1999Also published asUS6812624, US7049732, US7199501, US7224106, US7259503, US7468575, US7923064, US8508109, US20040263028, US20060113878, US20060113880, US20060238079, US20080136052, US20110154641, US20110155307Publication number11774918, 774918, US 2008/0191585 A1, US 2008/191585 A1, US 20080191585 A1, US 20080191585A1, US 2008191585 A1, US 2008191585A1, US-A1-20080191585, US-A1-2008191585, US2008/0191585A1, US2008/191585A1, US20080191585 A1, US20080191585A1, US2008191585 A1, US2008191585A1InventorsRonald E. Pelrine, Roy D. Kornbluh, Qibing Pei, Jose P. JosephOriginal AssigneeSri InternationalExport CitationBiBTeX, EndNote, RefManReferenced by (6), Classifications (45), Legal Events (3) External Links: USPTO, USPTO Assignment, EspacenetElectroactive polymer electrodesUS 20080191585 A1Abstract Described herein are transducers, their use and fabrication. The transducers convert between mechanical and electrical energy. The present invention further relates to compliant electrodes that conform to the shape of a polymer included in a transducer.
a compliant portion in contact with a portion of the electroactive polymer, wherein the compliant portion comprises one or more regions of high conductivity and one or more regions of low conductivity, and wherein the one or more regions of low conductivity comprise a charge distribution layer that has a conductance greater than the electroactive polymer. 2. The electrode of claim 1 wherein the regions of high conductivity comprise a set of patterned traces.
CROSS-REFERENCE TO RELATED APPLICATIONS This application is a divisional of and claims priority under U.S.C. �120 from co-pending U.S. patent application Ser. No. 11/335,805, filed Jan. 18, 2006, which is incorporated herein for all purposes; the Ser. No. 11/335,805 patent application is a continuation application and claimed priority under U.S.C. �120 from U.S. patent application Ser. No. 10/893,730, filed Jul. 16, 2004, now U.S. Pat. No. 7,049,732, issued May 23, 2006, which is incorporated herein for all purposes; the Ser. No. 10/893,730 patent application is a divisional application of and claimed priority under U.S.C. �120 from U.S. patent application Ser. No. 09/619,847, filed Jul. 20, 2000, now U.S. Pat. No. 6,812,624 B1, issued Nov. 2, 2004, which is incorporated herein for all purposes; the U.S. Pat. No. 6,812,624 B1 patent claimed priority under 35 U.S.C. � 119(e) from i) U.S. Provisional Patent Application No. 60/144,556 filed Jul. 20, 1999, naming R. E. Pelrine et al. as inventors, and titled �High-speed Electrically Actuated Polymers and Method of Use�, which is incorporated by reference herein for all purposes, ii) U.S. Provisional Patent Application No. 60/153,329 filed Sep. 10, 1999, naming R. E. Pelrine et al. as inventors, and titled �Electrostrictive Polymers As Microactuators�, which is incorporated by reference herein for all purposes, iii) U.S. Provisional Patent Application No. 60/161,325 filed Oct. 25, 1999, naming R. E. Pelrine et al. as inventors, and titled �Artificial Muscle Microactuators�, which is incorporated by reference herein for all purposes, iv) U.S. Provisional Patent Application No. 60/181,404 filed Feb. 9, 2000, naming R. D. Kornbluh et al. as inventors, and titled �Field Actuated Elastomeric Polymers�, which is incorporated by reference herein for all purposes, v) U.S. Provisional Patent Application No. 60/187,809 filed Mar. 8, 2000, naming R. E. Pelrine et al. as inventors, and titled �Polymer Actuators and Materials�, which is incorporated by reference herein for all purposes; vi) U.S. Provisional Patent Application No. 60/192,237 filed Mar. 27, 2000, naming R. D. Kornbluh et al. as inventors, and titled �Polymer Actuators and Materials II�, which is incorporated by reference herein for all purposes, and vii) U.S. Provisional Patent Application No. 60/184,217 filed Feb. 23, 2000, naming R. E. Pelrine et al. as inventors, and titled �Electroelastomers and their use for Power Generation�, which is incorporated by reference herein for all purposes.
Overview Electroactive polymers deflect when actuated by electrical energy. In one embodiment, an electroactive polymer refers to a polymer that acts as an insulating dielectric between two electrodes and may deflect upon application of a voltage difference between the two electrodes. In one aspect, the present invention relates to polymers that are pre-strained to improve conversion between electrical and mechanical energy. The pre-strain improves the mechanical response of an electroactive polymer relative to a non-strained electroactive polymer. The improved mechanical response enables greater mechanical work for an electroactive polymer, e.g., larger deflections and actuation pressures. For example, linear strains of at least about 200 percent and area strains of at least about 300 percent are possible with pre-strained polymers of the present invention. The pre-strain may vary in different directions of a polymer. Combining directional variability of the pre-strain, different ways to constrain a polymer, scalability of electroactive polymers to both micro and macro levels, and different polymer orientations (e.g., rolling or stacking individual polymer layers) permits a broad range of actuators that convert electrical energy into mechanical work. These actuators find use in a wide range of applications.
General Structure of Devices FIGS. 1A and 1B illustrate a top perspective view of a transducer 100 in accordance with one embodiment of the present invention. The transducer 100 includes a polymer 102 for converting between electrical energy and mechanical energy. Top and bottom electrodes 104 and 106 are attached to the electroactive polymer 102 on its top and bottom surfaces respectively to provide a voltage difference across a portion of the polymer 102. The polymer 102 deflects with a change in electric field provided by the top and bottom electrodes 104 and 106. Deflection of the transducer 100 in response to a change in electric field provided by the electrodes 104 and 106 is referred to as actuation. As the polymer 102 changes in size, the deflection may be used to produce mechanical work.
Actuator and Generator Devices The deflection of a pre-strained polymer can be used in a variety of ways to produce or receive mechanical energy. Generally speaking, electroactive polymers of the present invention may be implemented with a variety of actuators and generators�including conventional actuators and generators retrofitted with a pre-strained polymer and custom actuators and generators specially designed for one or more pre-strained polymers. Conventional actuators and generators include extenders, bending beams, stacks, diaphragms, etc. Several different exemplary custom actuators and generators in accordance with the present invention will now be discussed.
Performance A transducer in accordance with the present invention converts between electrical energy and mechanical energy. Transducer performance may be characterized in terms of the transducer by itself, the performance of the transducer in an actuator, or the performance of the transducer in a specific application (e.g., a number of transducers implemented in a motor). Pre-straining electroactive polymers in accordance with the present invention provides substantial improvements in transducer performance.
Electrodes As mentioned above, transducers of the present invention preferably include one or more electrodes for actuating an electroactive polymer. Generally speaking, electrodes suitable for use with the present invention may be of any shape and material provided they are able to supply or receive a suitable voltage, either constant or varying over time, to or from an electroactive polymer. In one embodiment, the electrodes adhere to a surface of the polymer. Electrodes adhering to the polymer are preferably compliant and conform to the changing shape of the polymer. The electrodes may be only applied to a portion of an electroactive polymer and define an active area according to their geometry.
In general, the charge distribution layer 503 has a conductance greater than the electroactive polymer but less than the metal traces. The non-stringent conductivity requirements of the charge distribution layer 503 allow a wide variety of materials to be used. By way of example, the charge distribution layer may comprise carbon black, fluoroelastomer with colloidal silver, a water-based latex rubber emulsion with a small percentage in mass loading of sodium iodide, and polyurethane with tetrathiafulavalene/tetracyanoquinodimethane (TTF/TCNQ) charge transfer complex. These materials are able to form thin uniform layers with even coverage and have a surface conductivity sufficient to conduct the charge between metal traces 502 before substantial charge leaks into the surroundings. In one embodiment, material for the charge distribution layer 503 is selected based on the RC time constant of the polymer. By way of example, surface resistivity for the charge distribution layer 503 suitable for the present invention may be in the range of about 106−1011 ohms. It should also be noted that in some embodiments, a charge distribution layer is not used and the metal traces 502 are patterned directly on the polymer. In this case, air or another chemical species on the polymer surface may be sufficient to carry charge between the traces. This effect may be enhanced by increasing the surface conductivity through surface treatments such as plasma etching or ion implantation. FIG. 4 illustrates a pre-strained polymer 510 underlying a structured electrode that is not directionally compliant according to a specific embodiment of the present invention. The structured electrode includes metal traces 512 patterned directly on one surface of the electroactive polymer 510 in evenly spaced parallel lines forming a �zig-zag� pattern. Two metal traces 512 on opposite surfaces of the polymer act as electrodes for the electroactive polymer 510 material between them. The �zig-zag� pattern of the metal traces 512 allows for expansion and contraction of the polymer and the structure electrode in multiple directions 514 and 516.
Applications As the present invention includes transducers that may be implemented in both the micro and macro scales, and with a wide variety of actuator designs, the present invention finds use in a broad range of applications where conversion between electrical and mechanical energy is required. Provided below are several exemplary applications for some of the actuators described above. Broadly speaking, the transducers and actuators of the present invention may find use in any application requiring conversion between electrical and mechanical energy. These applications include robotics, sensors, motors, toys, micro-actuator applications, pumps, generators, etc.
Fabrication As the pre-strained polymers may be implemented both in the micro and macro scales, in a wide variety of actuator designs, with a wide range of materials, and in a broad range of applications, fabrication processes used with the present invention may vary greatly. In one aspect, the present invention provides methods for fabricating electromechanical devices including one or more pre-strained polymers.
Referenced byCiting PatentFiling datePublication dateApplicantTitleUS7761981 *Apr 3, 2007Jul 27, 2010Sri InternationalMethods for fabricating an electroactive polymer deviceUS7906891 *Feb 29, 2008Mar 15, 2011Sony Ericsson Mobile Communications AbLight control of an electronic deviceUS8042264Jun 30, 2010Oct 25, 2011Sri InternationalMethod of fabricating an electroactive polymer transducerUS8093783May 24, 2010Jan 10, 2012Sri InternationalElectroactive polymer deviceUS8643463Nov 30, 2009Feb 4, 2014Nanyang PolytechnicPorous film sensorWO2011065921A1 *Nov 30, 2009Jun 3, 2011Nanyang PolytechnicA porous film sensor* Cited by examinerClassifications U.S. Classification310/363International ClassificationH04R19/02, F04B35/00, H04R23/00, F25B9/14, H01L41/193, F02G1/043, H01L41/113, H01L41/09, H02N2/04, F04B43/04, F04B35/04, H01L41/047Cooperative ClassificationH01L41/1138, F02G1/043, H01L41/0478, H02N2/023, H01L41/094, F04B35/045, H01L41/047, F02G2243/52, F04B35/00, H04R19/02, F04B43/043, F25B9/14, F05C2225/08, H01L41/0986, Y10S310/80, H01L41/193, H01L41/113, H04R23/00, H01L41/45European ClassificationH01L41/09G2B, H01L41/09L, H01L41/113M, H02N2/02B2, H01L41/047, H01L41/047M2, H01L41/45, F02G1/043, F04B35/00, F04B35/04S, H01L41/113, H01L41/193, F04B43/04MLegal EventsDateCodeEventDescriptionMay 23, 2012FPAYFee paymentYear of fee payment: 4Apr 25, 2008ASAssignmentOwner name: SRI INTERNATIONAL, CALIFORNIAFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:PELRINE, RONALD E.;KORNBLUH, ROY D.;PEI, QIBING;AND OTHERS;REEL/FRAME:020856/0593;SIGNING DATES FROM 20070814 TO 20070905Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:PELRINE, RONALD E.;KORNBLUH, ROY D.;PEI, QIBING;AND OTHERS;SIGNING DATES FROM 20070814 TO 20070905;REEL/FRAME:020856/0593Feb 7, 2008ASAssignmentOwner name: NAVY, SECRETARY OF THE, UNITED STATES OF AMERICA OFree format text: CONFIRMATORY LICENSE;ASSIGNOR:SRI INTERNATIONAL;REEL/FRAME:020483/0392Effective date: 20071016RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services©2012 Google