Visual Prosthesis Encapsulation with Parylene Fluid Barrier Layers
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Solution Overview
Problem
Implantable visual prostheses face challenges in maintaining corrosion-resistivity, leakproofness, and biological compatibility due to exposure to corrosive body fluids, affecting their use life and reliability.
Innovation Solution
An implantable device with a flexible cable, circuit chip, fluid adhesion layer, and vapor deposited layer, where the fluid adhesion layer is coated with silicone oil and the vapor deposited layer is made of Parylene, providing insulation and preventing corrosive fluids from permeating, and a barrier layer with low water vapor permeability for additional support and protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a visual prosthesis is implanted in the body, then it can restore visual sense through electrical stimulation, but it is exposed to corrosive body fluids causing corrosion and reducing reliability
Solution Approach 1:
The patent introduces a fluid adhesion layer as an intermediary substance between the circuit chip/lead-in part and the body fluid environment. This layer adheres to the device surfaces and prevents direct contact between corrosive body fluids and the electronic components, thereby protecting against corrosion while maintaining device functionality
Solution Approach 2:
The patent employs a composite protective structure consisting of multiple materials: a fluid adhesion layer (silicone oil-based) combined with a vapor deposited layer (Parylene). This multi-material composite provides enhanced corrosion resistance and leakproofness compared to single-material solutions, addressing the reliability issue through material composition
2Duration of action of stationary object
If the implantable device is exposed to body fluid for long-term use, then it can perform continuous stimulation, but the corrosive environment degrades the device over time
Solution Approach 1:
The patent applies protective layers (fluid adhesion layer and vapor deposited layer) beforehand to the device surfaces before implantation. These layers act as pre-established protective barriers that cushion the device against corrosive body fluids during long-term implantation, preventing degradation and extending use life
Solution Approach 2:
The fluid adhesion layer serves as a mediator between the device and body fluid environment, preventing direct corrosive interaction over extended periods. This intermediary protection enables long-term continuous stimulation while maintaining device integrity
3Reliability
If the device components are directly exposed to body fluid, then the structure remains simple, but the device lacks protection against fluid permeation
Solution Approach 1:
The patent uses thin film structures - a fluid adhesion layer and a vapor deposited Parylene layer - to provide protective encapsulation. These thin films create effective fluid barriers without adding significant structural complexity, maintaining leakproofness while keeping the device design relatively simple
Solution Approach 2:
The protective structure combines different material layers (fluid adhesion layer + vapor deposited layer) to achieve enhanced leakproofness. This composite approach provides superior protection compared to single layers, addressing reliability requirements without excessive complexity
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 solution enhances the leakproofness and operational reliability of the implantable device, ensuring a longer lifespan and improved biological compatibility by effectively preventing fluid ingress.
Implementation Method 1
The fluid adhesion layer is adhered to an outer side of the circuit chip and an outer side of the lead-in part
Implementation Method 2
The vapor deposited layer is directly deposited on an outer side of the fluid adhesion layer
Implementation Method 3
a barrier layer with low water vapor permeability for additional support and protection
Data Source
AI summary
An implantable device includes a flexible cable, a circuit chip, a fluid adhesion layer, and a vapor deposited layer. The flexible cable includes a lead-in part, a stimulation part and a connection part connected between the lead-in part and the stimulation part. The circuit chip is fixed to a surface of one side of the lead-in part, and is electrically connected to the lead-in part. The fluid adhesion layer is adhered to an outer side of the circuit chip and an outer side of the lead-in part. The vapor deposited layer (4) is directly deposited on an outer side of the fluid adhesion layer.