Flexible Circuit Electrode Array for Improved Layer Adhesion

• US 20120239125A1
• Filed: 05/08/2012
• Published: 09/20/2012
• Est. Priority Date: 12/03/2004
• Status: Active Grant

• Current Assignee: Cortigent Incorporated, Doheny Eye Institute
• Original Assignee: Doheny Eye Institute
• Inventors: Greenberg, Robert Jay, Humayun, Mark S.
• Granted Patent: US 8,874,224 B2
• Time in Patent Office: Days
• US Class Current: 607/116
• CPC Class Codes: A61N 1/0543 Retinal electrodes
• CPC Class Codes: A61N 1/36046 of the eye

Abstract

The present invention is a flexible circuit electrode array for improved layer adhesions where the metal conductors overlap the polymer insulator. The steps to build the flexible circuit are as follows. Deposit a base polymer layer. Deposit a conductive trace over the base polymer layer. Deposit a top polymer layer over the trace and prepare a void in the top polymer layer smaller than the surface of the trace. Deposit an electrode on the trace through the void with a periphery larger than, and overlapping the void.

Claims

1. A flexible circuit electrode array comprising:

a base polymer layer;

a conductive trace deposited on the base polymer layer;

a top polymer layer deposited on the base polymer layer and the trace, and defining a void;

the trace forming an electrode base extending peripherally beyond the void; and

an electrode connected to the electrode base through the void and extending peripherally beyond the void.

2. The flexible circuit electrode array of claim 1 wherein base polymer layer and top polymer layers contain polyfluorocarbons, polyethylene, polypropylene, silicone, polyamide, polyimide, liquid crystal polymer, poly-paraxylylene, polyaryletherketone and/or derivatives and/or mixtures thereof.

3. The flexible circuit electrode array of claim 1, wherein the conductive trace contains a base conducting layer, an intermediate conducting layer and a top conducting layer.

4. The flexible circuit electrode array of claim 3, wherein the intermediate conducting layer contains platinum, tantalum, iridium, palladium, rhodium, rhenium, gold, chrome, molybdenum, or carbon, or an alloy thereof or a combination of two or more alloys or metal layers thereof.

5. The flexible circuit electrode array of claim 3 ,wherein the base conducting layer and the top conducting layers contain titanium, and the intermediate conducting layer contains whereby the trace forms a titanium/platinum/titanium film stack.

6. The electrode array of claim 1 wherein the electrode comprises a surface coating, the surface coating having at least 5 times the surface area of that for the corresponding surface area resulting from the basic geometric shape of the electrode.

7. The flexible circuit electrode array of claim 1 wherein the electrode comprises a surface coating, the surface coating being biocompatible.

8. The flexible circuit electrode array of claim 1 wherein the electrode comprises a surface coating, the surface coating having a surface area of less than 500 times the corresponding surface area resulting from the basic geometric shape.

9. The flexible circuit electrode array of claim 1 wherein the electrode comprises a surface coating, the surface coating comprising platinum having a fractal configuration, titanium nitride, iridium oxide, or mixtures thereof.

10. The flexible circuit electrode array of claim 1, wherein the top polymer layer and the base polymer layer are made of different polymers.

11. The flexible circuit electrode array of claim 10, wherein the top polymer layer is made of a polymer softer than the polymer of the base polymer layer.

12. The flexible circuit electrode array of claim 11, wherein the base polymer layer is made of polyimide and the top polymer layer is made of silicone.

13. The flexible circuit electrode array of claim 1, wherein the conductive trace separates the electrode from the base polymer layer.

14. The flexible circuit electrode array of claim 1, wherein the electrode protrudes from the top polymer layer.

15. The flexible circuit electrode array according to claim 1, wherein the electrode is thicker than the trace.

16. The flexible circuit electrode array according to claim 1, wherein the trace is wider at the electrode than it is along the rest of its length.