Dual-Polymer Shell for Coil Alignment in Hearing Implants
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Solution Overview
Problem
Existing middle ear implant devices face challenges in achieving optimal alignment between the magnet and coil, leading to reduced energy transmission and requiring multiple external processor assemblies, which is costly and time-consuming.
Innovation Solution
A sound processor assembly with a dual-polymer shell, where one polymer does not soften with heat and the other does, allowing the coil to be repositioned without damaging the shell, using a second polymer that softens and returns to a rigid state, enabling precise alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thermoset polymers are used for the ear mold shell, then the shell maintains structural integrity and rigidity, but the coil cannot be repositioned as the material does not soften when heated
Solution Approach 1:
The patent divides the shell into two distinct polymer zones: a first polymer zone (thermoset) providing structural integrity and a second polymer zone (thermoplastic) providing coil repositionability. This segmentation allows each zone to fulfill its specific function without compromising the other.
Solution Approach 2:
The patent applies different material properties to different regions of the shell. The first polymer zone maintains rigidity for structural support, while the second polymer zone provides thermal softening capability for coil adjustment. This local differentiation resolves the contradiction between overall shell strength and localized repositionability.
2Adaptability or versatility
If thermoplastics are used for the shell to allow coil movement, then the material softens when heated enabling repositioning, but the shell becomes very viscous requiring expensive manufacturing processes
Solution Approach 1:
The patent limits the thermoplastic material to only the second polymer zone needed for coil repositioning, rather than using it for the entire shell. This segmentation reduces the amount of thermoplastic material required and simplifies the manufacturing process compared to making the whole shell from thermoplastic.
Solution Approach 2:
The patent creates a composite structure combining thermoset and thermoplastic polymers in a single shell. This composite approach allows the shell to benefit from the ease of shaping of thermoplastics in the second zone while maintaining the structural integrity and manufacturing simplicity of thermosets in the first zone.
3Adaptability or versatility
If thermoplastics are heated to allow coil movement, then the material becomes pliable for repositioning, but the shell itself softens and may deform losing its proper fit in the ear canal
Solution Approach 1:
The patent divides the shell into thermal zones where only the second polymer zone softens at the heating temperature used for coil repositioning. The first polymer zone remains rigid and maintains the shell's overall shape and fit in the ear canal, preventing deformation while allowing coil movement.
Solution Approach 2:
The patent applies differential thermal response to different regions of the shell. The second polymer zone is selected to soften at a specific temperature for coil adjustment, while the first polymer zone maintains its shape-stabilizing properties at that same temperature. This local quality differentiation resolves the contradiction between repositionability and shape retention.
4Manufacturing precision
If multiple external processor assemblies are made with different coil positions, then optimal alignment can be achieved, but the process is expensive and requires many clinical visits
Solution Approach 1:
The patent makes the shell dynamically adjustable by incorporating a thermoplastic second polymer zone that can be heated to allow coil repositioning. This dynamic capability eliminates the need for multiple static processor assemblies, allowing optimization of coil-magnet alignment within a single device and reducing clinical visits.
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
Enables precise and cost-effective alignment of the magnet and coil, reducing the need for multiple processor assemblies and minimizing clinical visits, while maintaining the shell's integrity and fit within the ear canal.
Implementation Method 1
a first polymer that does not soften when heat is applied
Implementation Method 2
a second polymer which does... become pliable or moldable above a specific temperature
Implementation Method 3
return to a solid state upon cooling
Implementation Method 4
placing it near to a coil of wire which is energized by the flow of electricity. Once such a coil of wire is energized by the flow of electricity, it becomes an 'electromagnet'
Implementation Method 5
If a permanent magnet is placed near this electromagnetic coil, the magnet will be attracted to, or repelled from, the coil
Data Source
Figure 1A~2B
Figure 3~5
Figure 6~8
AI summary
A sound processor assembly having a coil support device which allows for the coil to be moved without damaging the plastic components or deforming the shell body. This is done by making the ear shell of the sound processor assembly, whether an integrated sound processor assembly or a linked sound processor assembly, out of two separate polymers: a first polymer that does not soften when heat is applied, and a second polymer which does. The first polymer is used for the first polymer zone of the shell which is shaped to the ear canal, while the second polymer is used for the section of the shell which supports the coil. This allows the shell to be heated, thereby softening the second polymer but not the first, and allows the coil to be repositioned to a new location.