Photosensitive Pixel Dual-Layer Coating for Light and Hermetic Sealing
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Solution Overview
Problem
Existing photosensitive pixel structures in retinal implants face challenges in maximizing light transmission and absorption while maintaining a thin, hermetic, and biocompatible design to effectively stimulate residual retinal cells, which is crucial for restoring vision.
Innovation Solution
A photosensitive pixel structure is designed with a dual-layer interface coating comprising a thin oxide layer and a ceramic or ceramic-like layer on the substrate surface, optimized for light transmission and hermetic sealing, enhancing charge generation and reducing surface recombination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single-layer interface coating is used, then the structure is simple and manufacturing is easier, but light transmission is insufficient and charge generation is limited
Solution Approach 1:
The patent applies composite materials by combining a thin oxide layer (first material layer) with a ceramic or ceramic-like layer (second material layer) to form a dual-layer interface coating. This composite structure leverages the complementary properties of both materials: the oxide layer provides excellent light transmission and charge generation, while the ceramic layer enhances hermetic sealing and surface passivation, thereby achieving superior overall performance compared to a single-layer coating.
Solution Approach 2:
The interface coating is segmented into two distinct functional layers: a thin oxide layer (5-50 nm) optimized for light transmission and charge generation, and a thicker ceramic layer (50-500 nm) optimized for hermetic sealing and surface protection. This segmentation allows each layer to be independently optimized for its specific function, resolving the contradiction between simplicity and performance.
2Measurement precision
If the pixel size is reduced to increase resolution, then the implant provides higher resolution, but light absorption decreases and charge generation becomes insufficient
Solution Approach 1:
The patent changes the optical parameters of the interface coating by introducing a dual-layer structure with specific thicknesses (oxide layer: 5-50 nm, ceramic layer: 50-500 nm) and material compositions. This parameter optimization allows the coating to transmit more light to the photoactive region while maintaining effective charge collection, enabling high-resolution pixels to generate sufficient charge even at reduced sizes.
Solution Approach 2:
The dual-layer interface coating acts as an intermediary between the incident light and the photoactive region. The thin oxide layer serves as an anti-reflection layer that maximizes light transmission, while the ceramic layer provides a hermetic barrier. This intermediary structure enables efficient light coupling and charge generation in miniaturized pixels, resolving the resolution-efficiency trade-off.
3Length of moving object
If the substrate is made thinner to reduce implant thickness, then the implant is more compliant with tissue, but light transmission is blocked and charge generation is reduced
Solution Approach 1:
The patent optimizes the thickness parameters of the interface coating layers to compensate for the thinner substrate. By setting the oxide layer thickness to 5-50 nm and the ceramic layer thickness to 50-500 nm, the coating provides sufficient optical transmission and hermetic sealing even when the substrate is thin, maintaining charge generation efficiency without requiring increased substrate thickness.
4Reliability
If a thick coating is applied to improve hermetic sealing, then the seal is more effective, but light transmission decreases and charge generation is reduced
Solution Approach 1:
The patent uses a composite coating structure where the thin oxide layer (5-50 nm) provides excellent light transmission properties, while the thicker ceramic layer (50-500 nm) provides robust hermetic sealing. The combination allows the coating to achieve both effective sealing and high optical transmission, as each material contributes its strength to the overall system.
Solution Approach 2:
The coating is segmented into two functional layers with distinct roles: the oxide layer handles light transmission and charge generation, while the ceramic layer handles hermetic sealing. This segmentation allows the hermetic function to be performed by a thicker layer without compromising optical performance, as the thin oxide layer ensures sufficient light transmission.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The dual-layer coating increases light transmission and charge generation efficiency, allowing for a smaller pixel size with higher resolution and effective stimulation of neural tissue, thus improving the functionality of retinal implants.
Implementation Method 1
The interface layer at least partially comprises a first material layer and, further, a second material layer covering the first material layer... optimized for light transmission and hermetic sealing, enhancing charge generation
Implementation Method 2
a photosensitive pixel structure... optimized for light transmission and hermetic sealing, enhancing charge generation
Data Source
AI summary
The disclosure refers to a photosensitive pixel structure that includes a substrate layer and an interface layer. The interface layer is provided at least partially on a first surface of the substrate layer and the interface layer at least partially includes a first material layer and the interface layer at least partially includes a second material layer covering the first material layer such that the first material layer is at least partially sandwiched between the second material layer and the substrate. The disclosure further refers to an array and an implant that includes a pixel structure and a method for providing a pixel structure.