Conductive Overlays for Layered Heaters to Reduce Current Crowding
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Solution Overview
Problem
Layered heaters experience premature failure due to current crowding at curved portions of the resistive heating element trace, leading to increased current density and potential burning.
Innovation Solution
The implementation of conductive overlays at predetermined locations on the substrate, specifically at bend portions of the resistive circuit pattern, to distribute current density more evenly and reduce the risk of overheating, which can be formed using various layering processes such as thermal spraying or laser cutting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a resistive heating element trace with curved portions is used, then the heater can be customized for various heating applications, but current crowding occurs at the curved portions leading to increased current density and premature failure
Solution Approach 1:
The patent applies a conductive overlay material specifically at the curved portions of the resistive heating element trace where current crowding occurs. This local modification changes the electrical properties only at the problematic areas, maintaining the overall customized heater design while addressing the reliability issue at specific locations.
Solution Approach 2:
The patent uses a composite structure combining the resistive heating material with a conductive overlay material at the curved portions. This composite approach allows the heater to maintain its customized shape and heating characteristics while the conductive overlay redistributes current density to prevent premature failure.
2Power
If current density is increased at curved portions to maintain heating performance, then heating output is maintained, but burning occurs leading to premature failure
Solution Approach 1:
The patent changes the electrical conductivity parameter at the curved portions by applying a conductive overlay material. This parameter change allows the curved portions to carry higher current density without burning, maintaining heating output while improving reliability.
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 use of conductive overlays increases the life of the layered heater by distributing current density more uniformly, reducing the risk of overheating and extending the operational lifespan.
Implementation Method 1
The resistive material is applied to the dielectric material in a predetermined pattern and provides a resistive heater circuit
Implementation Method 2
thermally spraying a resistive material on the dielectric layer to form a resistive layer on the dielectric layer
Data Source
AI summary
A method of manufacturing a layered heater includes: applying a dielectric material on a substrate to form a dielectric layer; thermal-spraying a resistive material on the dielectric layer to form a resistive layer on the dielectric layer; forming a plurality of conductive overlays at predetermined locations on the substrate; and forming a plurality of cuts into the resistive layer by laser cutting to form a resistive circuit pattern that overlaps the conductive overlays.