Package for a retinal prosthesis
The present invention is an improved hermetic package for a retinal prosthesis implanted in the human body. The retinal prosthesis includes a flexible circuit electrode array suitable to stimulate the retina while connected to a hermetic package on the outside of the eye, the hermetic package including a cover and a base where the cover is bonded to the base such that the cover and base form the hermetic package.
1. A retinal prosthesis comprising:
a biocompatible package comprising
a planar base, including an electrically non-conductive substrate and biocompatible patterned metallization comprising gold on the non-conductive substrate,
a circuit attached directly to a first side of the base wherein the circuit is smaller than the base, and
a rounded cover, the base and the rounded cover forming the biocompatible package;
a molded polymer body pre-curved to match the curvature of a typical sclera and including suture tabs in the molded polymer body suitable to attach the biocompatible package to an outside surface of a sclera; and
a flexible circuit electrically connected to the circuit, the flexible circuit extending from the biocompatible package and suitable to pass through a pars plana and having an array of electrodes suitable to stimulate retinal tissue.
2. The retinal prosthesis according to claim 1 , wherein the molded body is curved to approximate the shape of the sclera.
3. The retinal prosthesis according to claim 1 , further comprising a coil receiving electrical power to power the circuit.
4. The retinal prosthesis according to claim 1 , wherein the electrically non-conductive substrate contains ceramic.
5. The retinal prosthesis according to claim 1 , wherein the patterned metallization is multiple layer metallization and the circuit is bonded to the patterned metallization.
6. The retinal prosthesis according to claim 5 , wherein the multiple layer metallization is chosen to withstand braze temperatures.
7. The retinal prosthesis according to claim 6 , wherein the multiple layer metallization comprises more than one of the metals titanium, tantalum, gold, palladium, platinum or layers or alloys thereof.
8. The retinal prosthesis according to claim 1 , wherein the circuit is a flip-chip integrated circuit.
9. The retinal prosthesis according to claim 1 , wherein the circuit is a wire bonded circuit.
10. The retinal prosthesis according to claim 1 , wherein the cover includes a wall and a lid and the wall is brazed to the base.
11. The retinal prosthesis according to claim 1 , wherein the flexible circuit is bump bonded to the base with conductive bumps.
12. The retinal prosthesis according to claim 8 , further comprising a polymer underfill under the flip-chip integrated circuit.
13. The retinal prosthesis according to claim 11 , wherein the conductive bumps contain at least one conductive polymer.
14. The retinal prosthesis according to claim 11 , wherein the conductive bumps contain at least one conductive epoxy or polyimide.
15. The retinal prosthesis according to claim 1 , further comprising a getter.
16. The retinal prosthesis according to claim 15 , wherein the getter is placed on the inside of the cover.