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High Performance 3-coil Wireless Power Transfer System for the 512-electrode Epiretinal Prosthesis

Zhao, Yu and Nandra, Mandheerej and Yu, Chia-Chen and Tai, Yu-Chong (2012) High Performance 3-coil Wireless Power Transfer System for the 512-electrode Epiretinal Prosthesis. In: 2012 Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC). IEEE , Piscataway, NJ, pp. 6583-6586. ISBN 978-1-4244-4119-8.

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The next-generation retinal prostheses feature high image resolution and chronic implantation. These features demand the delivery of power as high as 100 mW to be wireless and efficient. A common solution is the 2-coil inductive power link, used by current retinal prostheses. This power link tends to include a larger-size extraocular receiver coil coupled to the external transmitter coil, and the receiver coil is connected to the intraocular electrodes through a trans-sclera trans-choroid cable. In the long-term implantation of the device, the cable may cause hypotony (low intraocular pressure) and infection. However, when a 2-coil system is constructed from a small-size intraocular receiver coil, the efficiency drops drastically which may induce over heat dissipation and electromagnetic field exposure. Our previous 2-coil system achieved only 7% power transfer. This paper presents a fully intraocular and highly efficient wireless power transfer system, by introducing another inductive coupling link to bypass the trans-sclera trans-choroid cable. With the specific equivalent load of our customized 512-electrode stimulator, the current 3-coil inductive link was measured to have the overall power transfer efficiency around 36%, with 1-inch separation in saline. The high efficiency will favorably reduce the heat dissipation and electromagnetic field exposure to surrounding human tissues. The effect of the eyeball rotation on the power transfer efficiency was investigated as well. The efficiency can still maintain 14.7% with left and right deflection of 30 degree during normal use. The surgical procedure for the coils' implantation into the porcine eye was also demonstrated.

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Tai, Yu-Chong0000-0001-8529-106X
Additional Information:© 2012 IEEE. Date of Current Version: 10 November 2012; Issue Date: Aug. 28 2012-Sept. 1 2012. This work is supported by the Biomimetic MicroElectronic Systems (BMES) Center under the grant number H31068. The authors would like to thank Trevor Roper’s help in terms of sample preparation, machine maintenance, and instrument installation as well as the members of Caltech Micromachining Laboratory.
Funding AgencyGrant Number
Biomimetic MicroElectronic Systems (BMES) CenterH31068
Record Number:CaltechAUTHORS:20121120-114631007
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Official Citation:Zhao, Yu; Nandra, Mandheerej; Yu, Chia-Chen; Tai, Yu-chong; , "High performance 3-coil wireless power transfer system for the 512-electrode epiretinal prosthesis," Engineering in Medicine and Biology Society (EMBC), 2012 Annual International Conference of the IEEE , vol., no., pp.6583-6586, Aug. 28 2012-Sept. 1 2012 doi: 10.1109/EMBC.2012.6347503
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:35568
Deposited By: Jason Perez
Deposited On:20 Nov 2012 22:22
Last Modified:09 Nov 2021 23:16

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