Flexible circuit electrode array

Patent metadata

Field	Value
Publication number	US-10667404-B2
Application number	US-92604607-A
Country	US
Kind code	B2
Filing date	Oct 28, 2007
Priority date	Apr 28, 2005
Publication date	May 26, 2020
Grant date	May 26, 2020

Abstract

Polymer materials are useful as electrode array bodies for neural stimulation. They are particularly useful for retinal stimulation to create artificial vision, cochlear stimulation to create artificial hearing, or cortical stimulation many purposes. The pressure applied against the retina, or other neural tissue, by an electrode array is critical. Too little pressure causes increased electrical resistance, along with electric field dispersion. Too much pressure may block blood flow. Common flexible circuit fabrication techniques generally require that a flexible circuit electrode array be made flat. Since neural tissue is almost never flat, a flat array will necessarily apply uneven pressure. Further, the edges of a flexible circuit polymer array may be sharp and cut the delicate neural tissue. By applying the right amount of heat to a completed array, a curve can be induced. With a thermoplastic polymer it may be further advantageous to repeatedly heat the flexible circuit in multiple molds, each with a decreasing radius. Further, it is advantageous to add material along the edges. It is further advantageous to provide a fold or twist in the flexible circuit array. Additional material may be added inside and outside the fold to promote a good seal with tissue.

First claim

The invention claimed is:

1. A method of making a flexible electrode array for neural stimulation comprising:
depositing a polymer base layer;
depositing platinum on said polymer base layer;
patterning said platinum by wet etch to form a plurality of metal traces, a plurality of bond pads and a plurality of electrodes, each electrode connected to a bond pad through a metal trace, and the bond pads configured to connect to an implantable electronics package;
electroplating platinum at the electrodes and bond pads to make the electrodes and bond pads thicker, such that the electrodes are suitable to stimulate neural tissue;
depositing a polymer top layer on said polymer base layer, said metal traces, bond pads and electrodes;
forming openings in the polymer top layer directly over the electrodes, and smaller than the electrodes, leaving at least a portion of each electrode extending under said polymer top layer opposite the metal trace;
thermoforming the array in a mold to form a pre-curved surface suitable to contact neural tissue; and
forming a skirt of soft polymer, softer than said polymer base layer, and bonding the skirt to the polymer base layer and molding the skirt around curved edges of the flexible electrode array in the portion including the electrodes;
wherein the final flexible electrode array includes electrodes, traces, and bond pads on a continuous polymer base layer; and
wherein the final flexible electrode array has openings through the top polymer layer over each electrode smaller than the electrode, leaving at least a portion of each electrode extending under said polymer top layer opposite the metal trace, leaving no exposed electrode edges.

2. The method according to claim 1 further comprising precurving said flexible electrode array in a mold to form a precurved surface suitable to contact neural tissue comprising steps of heating said flexible electrode array in successively smaller molds.

3. The method according to claim 1 , wherein said step of depositing said polymer base layer and said polymer top layer is depositing polyimide.

4. The method according to claim 1 , wherein said step of depositing said polymer base layer and said polymer top layer is depositing silicone.

5. The method according to claim 1 , wherein said step of depositing said polymer base layer and said polymer top layer is depositing fluoropolymer.

6. The method according to claim 1 , further comprising forming a twist in flexible electrode array cable portion of said flexible electrode array.

7. The method according to claim 1 , further comprising bonding at least one bumper to a peripheral edge of the flexible circuit electrode array.

8. The method according to claim 1 , wherein depositing the polymer top layer is depositing a more compliant polymer than the polymer base layer.

9. The method according to claim 1 , further comprising forming a stress relief membrane on the flexible electrode array, wherein the stress relief membrane is a more compliant material than the polymer base layer.

10. The method according to claim 1 , further comprising forming a widened portion of the flexible electrode array suitable to resist movement.

11. The method according to claim 1 , further comprising forming a partial loop in flexible electrode array to resist transmission of force through the flexible circuit electrode array.

12. The method according to claim 1 , wherein the step of patterning electrodes is patterning electrodes in a pattern longer in one dimension than another dimension.

Assignees

• Greenberg Robert
• Talbot Neil
• Neysmith Jordan
• Guven Dilek
• Little James
• Mech Brian
• Humayun Mark
• Second Sight Medical Products Inc
• Doheny Eye Inst

Inventors

• Greenberg Robert
• Talbot Neil
• Neysmith Jordan
• Guven Dilek
• Little James
• Mech Brian
• Humayun Mark

Classifications

• A61N1/0543 Primary

  Retinal electrodes · CPC title

• Y10T29/49124

  On flat or curved insulated base, e.g., printed circuit, etc. · CPC title

• A61N1/36046

  of the eye · CPC title

• A61N1/0541

  Cochlear electrodes · CPC title

• A61N1/36036

  of the outer, middle or inner ear · CPC title