Flexible Circuit Electrode Array for Retinal Prosthesis
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Solution Overview
Problem
Existing electrode arrays for neural stimulation, particularly in retinal prostheses, face challenges in maintaining effective contact with the retina due to lack of mechanical stability and uneven current distribution, leading to reduced resolution and efficacy in visual perception for the visually impaired.
Innovation Solution
A flexible circuit electrode array device with a polymer layer having metal traces and an electrode array on the opposite side, allowing for backside processing to expose conductors on both sides, enabling secure attachment to the retina and electronic package without folding, thus ensuring consistent current distribution and improved mechanical stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional electrode arrays are used for retinal prostheses, then the device can be implanted, but mechanical stability and current distribution uniformity are insufficient
Solution Approach 1:
The patent employs a flexible polymer substrate (such as polyimide) as the base material for the electrode array, allowing the device to conform to the curved retinal surface. This flexible thin film structure provides mechanical stability while maintaining uniform contact with the retina, thereby ensuring consistent current distribution across all electrodes during stimulation.
Solution Approach 2:
The electrode array is designed with a curved configuration that matches the spherical geometry of the retinal surface. This curvature ensures that all electrodes maintain equidistant contact with the retina, eliminating uneven pressure points and ensuring uniform current distribution across the entire array during neural stimulation.
2Measurement precision
If electrodes are placed close together to improve resolution, then visual perception resolution improves, but current distribution becomes uneven
Solution Approach 1:
The flexible polymer substrate enables high-density electrode placement while maintaining uniform spacing through its conformability to the retinal surface. The flexibility allows closely spaced electrodes to all maintain consistent distance from the retina, preventing current distribution unevenness even at high resolutions.
Solution Approach 2:
The curved design of the electrode array ensures that closely spaced electrodes maintain uniform distance from the retinal surface throughout the array. This geometric configuration prevents current overlap and distribution irregularities that would otherwise occur with high-density electrode placement on a flat surface.
3Strength
If the device is made rigid for structural stability, then mechanical strength improves, but adaptability to retinal surface decreases
Solution Approach 1:
The patent utilizes a flexible polymer substrate that combines adequate structural strength with high flexibility. This thin film structure can withstand implantation forces while simultaneously conforming to the curved retinal surface, achieving both structural stability and surface adaptability through the inherent properties of flexible polymer materials.
Data Source
AI summary
The invention involves a flexible circuit electrode array device comprising: a polymer layer; wherein the polymer layer includes one or more metal traces, an electrode array; one or more bond pads; and the electrode array is located on the opposite side of the polymer layer.The invention further involves a method for backside processing of a flexible circuit electrode device, comprising: applying polymer film on a substrate; processing the front side; releasing the polymer film from substrate; flipping over the polymer film and fixing it onto the substrate; processing the backside; and final releasing of the polymer film from the substrate.The invention further involves a method for backside processing of a flexible circuit electrode device, comprising: processing the front side without releasing the polymer; processing the backside by sacrificial substrate method, or by laser drilling method; and releasing the polymer film from the substrate.