3-COIL WIRELESS POWER TRANSFER SYSTEM FOR EYE IMPLANTS

• US 20140058506A1
• Filed: 08/22/2013
• Published: 02/27/2014
• Est. Priority Date: 08/22/2012
• Status: Active Grant

• Current Assignee: California Institute of Technology, University of Southern California
• Original Assignee: California Institute of Technology, University of Southern California
• Inventors: Tai, Yu-Chong, Humayun, Mark, Weiland, James D., Zhao, Yu
• Granted Patent: US 9,078,743 B2
• Time in Patent Office: Days
• US Class Current: 623/4.1
• CPC Class Codes: A61F 2/14 Eye parts, e.g. lenses, corneal implants; Implanting instruments specially adapted therefor; Artificial eyes
• CPC Class Codes: A61F 2250/0001 Means for transferring electromagnetic energy to implants
• CPC Class Codes: A61F 9/007 Methods or devices for eye surgery
• CPC Class Codes: A61N 1/0529 Electrodes for brain stimulation
• CPC Class Codes: A61N 1/0543 Retinal electrodes
• CPC Class Codes: A61N 1/0551 Spinal or peripheral nerve electrodes
• CPC Class Codes: A61N 1/36046 of the eye
• CPC Class Codes: A61N 1/3605 Implantable neurostimulators for stimulating central or peripheral nerve system
• CPC Class Codes: A61N 1/3787 from an external energy source
• CPC Class Codes: C23F 1/00 Etching metallic material by chemical means manufacture of printing surfaces B41C; manufacture of printed circuits H05K
• CPC Class Codes: H01F 2027/2809 on stacked layers
• CPC Class Codes: H01F 27/2804 Printed windings

Abstract

A three-coil electromagnetic induction power transfer system is disclosed for epiretinal prostheses and other implants. A third, buffer coil is disposed between an external transmitting coil and a receiver coil buried within the body to improve efficiency and robustness to misalignments. One or more of the coils can be manufactured using micromechanical machining techniques to lay out conductors in a ribbon of biocompatible insulator, folding lengths of the insulated conductor traces longitudinally over one another, and then spiraling them into a ring. The traces change axial position in the ring by shifting across fold lines. One or more U-shaped sections on the traces can be folded so that adjacent traces can project opposite one another, lengthening the resulting ribbon that can be wound into a coil.

Claims

1. An inductively-powered eye implant apparatus comprising:

a buffer coil adapted to be affixed external to a sclera of an eye, the buffer coil having a conductor covered by a biocompatible layer;

a receiver coil adapted for implantation within the eye, the receiver coil having a conductor covered by a biocompatible layer, the receiver coil adapted for receiving electrical power by electromagnetic induction through the buffer coil from a transmitter coil, the buffer coil and receiving coil adapted to be electromagnetically coupled when affixed external to and implanted within the eye, respectively; and

a processing circuit connected with the conductor of the receiver coil and configured to receive electrical power from the receiver coil.

3. The apparatus of claim 1 wherein the buffer coil is suitable for mounting around the cornea and under the conjunctiva of the eye.

4. The apparatus of claim 1 further comprising:

a sclera lens encasing the buffer coil, the sclera lens adapted to be worn on the sclera to thereby affix the buffer coil external to the sclera of the eye.

6. The apparatus of claim 1 wherein the buffer coil is oval and has an outer minor axis of about 19 millimeters and an outer major axis of about 24 millimeters, the buffer coil adapted to be affixed external to the sclera such that the outer major axis is substantially horizontal.

8. The apparatus of claim 1 wherein the receiver coil is suitable for implantation within a lens capsule of the eye.

11. The apparatus of claim 1 further comprising:

a sealed cavity attached to the receiver coil; and

a fluid disposed within the sealed cavity, the fluid having a specific gravity less than aqueous solution,

thereby adding buoyancy to the receiver coil.

14. The apparatus of claim 1 wherein:

the buffer coil is adapted to be affixed to a side of the eye external to the sclera; and

the receiver coil is adapted for mounting within a vitreous body of the eye inside the sclera to an internal side of the eye.

15. The apparatus of claim 1 wherein the receiver coil has a cross section that is substantially wider axially than radially, allowing the receiver coil to be resiliently pinched to fit through an incision.

16. The apparatus of claim 1 wherein the receiver coil comprises etched conductors within a folded ribbon of electrical insulator.

17. The apparatus of claim 1 wherein the receiver coil was produced by:

etching conductor traces on an electrically insulative sheet;

depositing electrical insulator over the etched conductor traces sufficient to embed the etched conductor traces;

folding the sheet over onto itself, stacking the embedded conductor traces; and

then

winding the folded sheet in a spiral to form a closed shape.

18. The apparatus of claim 17 wherein each stacked conductor trace travels across at least one longitudinal fold crease such that respective conductor trace discretely shifts radial position in the spiral at each fold crease crossing.

19. The apparatus of claim 18 wherein each stacked conductor trace progresses parallel with at least one other stacked conductor trace before traveling across the at least one longitudinal fold crease to be radially separated from the at least one other stacked conductor trace.

21. The apparatus of claim 17 wherein the conductor traces on the electrically insulative sheet include a U-shaped region connecting two lengths of conductor traces that project in a same direction from the U-shaped region, the production of the receiver coil further produced by:

folding the sheet, before the winding, such that the U-shaped region is perpendicular to the sheet; and

then

folding the U-shaped region such that the lengths of conductor traces project in opposite directions from the U-shaped region.

32. The apparatus of claim 1 wherein the buffer coil is affixed to the eye or the receiving coil is implanted within the eye.

2. (canceled)

5. (canceled)

7. (canceled)

9-10. -10. (canceled)

12-13. -13. (canceled)

20. (canceled)

22-31. -31. (canceled)

33. A method of efficiently receiving power inside an eye for an intraocular electronic device without an sclera-piercing cable, the method comprising:

receiving, into a buffer coil affixed external to a sclera of an eye, a varying magnetic field by way of a first electromagnetic induction, the varying magnetic field causing current in the buffer coil;

inducing current, within a receiver coil within the eye, by way of a second electromagnetic induction from the current in the buffer coil to the receiver coil; and

powering an intraocular electronic device using the induced current from the receiver coil.

34. The method of claim 33 further comprising:

rectifying the induced current from the receiver coil to generate direct current.

35-50. -50. (canceled)

51. An inductively-powered implant apparatus comprising:

a buffer coil adapted to be affixed within a portion of a body of a patient, the buffer coil having a conductor covered by a biocompatible layer;

a receiver coil adapted for implantation within a deeper portion of the body than the buffer coil, the receiver coil having a conductor covered by a biocompatible layer, the receiver coil adapted for receiving electrical power by electromagnetic induction through the buffer coil from a transmitter coil, the buffer coil and receiving coil adapted to be electromagnetically coupled; and

a processing circuit connected with the conductor of the receiver coil and configured to receive electrical power from the receiver coil.

52. The apparatus of claim 51 wherein the portion of the body includes a head, and the processing circuit includes a brain pacemaker.

53. The apparatus of claim 51 wherein the portion of the body includes a torso, and the processing circuit includes a spinal cord stimulator.

54. The apparatus of claim 51 further comprising:

a rechargeable battery configured to receive electrical power through and be recharged by the processing circuit.