Exterior Insulator for Implantable Power Source Using Segmented Polyester Film
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Solution Overview
Problem
Existing implantable medical devices face challenges in achieving effective electrical isolation of power sources due to the impracticality of forming thin, formable polymeric films that can adequately cover the three-dimensional shape of electrochemical cells or capacitors.
Innovation Solution
The use of two or more inter-locking, shallow-formed shaped covers made of polyester film provides effective electrical insulation by being readily formable into the desired three-dimensional form factor while maintaining the desired film thinness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of stationary object
If a thin polyimide film is used for electrical isolation, then the internal volume is minimized, but the film cannot be easily formed into three-dimensional shapes
Solution Approach 1:
The patent divides the continuous polyimide film into multiple separate strips that can be individually formed and then assembled together to create the three-dimensional insulation structure, resolving the contradiction between thinness and formability
Solution Approach 2:
The patent transitions from a two-dimensional flat film to a three-dimensional insulation structure by folding and assembling multiple strips vertically, maintaining thinness while achieving complex geometry
2Ease of manufacture
If a formable polyester film is used instead, then the film can be formed into three-dimensional shapes, but the film thickness must be increased making it impractical
Solution Approach 1:
By segmenting the polyester film into multiple thin strips, the patent achieves three-dimensional formability without increasing overall thickness, as the strips are assembled vertically rather than requiring a single thick film
3Reliability
If a parylene coating is applied to the power source exterior, then electrical isolation is achieved, but the coating is difficult to apply and easily damaged
Solution Approach 1:
The patent introduces a polyimide film as an intermediary layer between the parylene coating and the external environment, providing mechanical protection to the fragile coating while maintaining electrical isolation
4Ease of manufacture
If masking is used to protect terminal pins during parylene coating, then selective coating is achieved, but removing the masking material can damage the terminal pin
Solution Approach 1:
The patent extracts the masking step entirely by using a pre-formed polyimide film structure that provides selective coverage, eliminating the risk of terminal pin damage during mask removal
Data Source
AI summary
A polymeric film cover assembly for isolating an electrochemical power source from the other components housed inside an implantable medical device is described. The cover assembly comprises a first shallow-formed shaped-cover of a polymeric film configured to cover a first portion of the exterior surface of the casing and a second shallow-formed shaped-cover of the polymeric film configured to cover a second portion of the exterior surface of the casing. With the first and second shaped-covers contacting the casing, the shaped-covers are connected to each other in an overlapping or butted relationship to substantially or completely cover the exterior surface area of the casing. The interlocking polyester shaped-covers are readily formable into the desired three-dimensional form factor of the casing of power source while maintaining a desirable film thinness.