Heater Circuit Track Pattern for Thermal Uniformity
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Solution Overview
Problem
Existing heater plates face challenges in achieving high temperature uniformity and fast heating with low power consumption, particularly due to issues like current crowding, thermal runaway, and increased mass and volume from additional layers, which lead to localized overheating and stress.
Innovation Solution
A heater circuit track pattern is designed with a conductive layer and a resistive layer coated on a substrate, featuring a specific pattern to distribute power evenly and prevent overheating, using a high thermal conductivity substrate with no additional layers to minimize volume and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional insulator layer is applied over aluminum substrate to eliminate high thermal expansion coefficient issues, then substrate reliability is improved, but heat capacity increases due to increased mass and volume
Solution Approach 1:
The patent removes the additional insulator layer from the heater construction, extracting only the essential substrate layer that provides both structural support and thermal management. This eliminates the extra mass and volume associated with multiple layers while maintaining substrate reliability through proper material selection and track pattern design.
Solution Approach 2:
The substrate layer is designed to perform multiple functions simultaneously: providing mechanical support, managing thermal expansion, and serving as the heating element base. This multi-functionality eliminates the need for separate insulator layers, reducing overall mass and heat capacity while maintaining reliability.
2Volume of moving object
If compact track pattern with tight turns is used to reduce volume and power consumption, then volume is reduced, but current crowding phenomenon causes localized overheating and thermal hot spots
Solution Approach 1:
The patent applies different track patterns in different regions of the heater. Areas prone to current crowding use wider tracks or different geometries to distribute current evenly, while other areas use compact patterns for space efficiency. This localized optimization maintains temperature uniformity throughout the heater surface.
Solution Approach 2:
The patent transitions from two-dimensional tight turns to three-dimensional track routing that goes around critical areas. By utilizing the Z-dimension (vertical spacing and layered routing), the design achieves compact footprint without creating current crowding issues in any particular region.
3Device complexity
If tight turns of resistive track pattern are implemented to achieve compact design, then device complexity is reduced, but stress concentration causes cracks and short circuits at joint parts
Solution Approach 1:
The patent incorporates stress-relief features and rounded corners in the track pattern design before manufacturing. These design elements pre-compensate for thermal expansion stresses that will occur during operation, preventing crack initiation at sharp corners and joint areas before they can develop into failures.
Solution Approach 2:
The patent modifies geometric parameters of the track pattern, specifically increasing minimum bend radii and adjusting track widths at junction points. These parameter changes reduce stress concentration factors while maintaining compact overall dimensions, preventing crack formation under thermal cycling conditions.
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 achieves high thermal uniformity with low power consumption and fast heating, avoiding current crowding and thermal runaway, while maintaining a compact design suitable for low volume applications.
Implementation Method 1
a resistive layer 103, coated on the heating circuit surface 105 after the conductive layer 102 is coated, having resistive portions comprising resistive parts formed by a resistive ink to heat up the heater plate 100
Implementation Method 2
a substrate layer 101, the bottom layer of the heater plate 100, which is electrically insulative, thermally high conductive
Data Source
AI summary
A heater circuit track pattern designed to be coated on a heater plate in order to achieve high uniform heat distribution and fast heating up, low power consumption and prevent current crowding with high fill factor. The heater plate includes a substrate layer which is an electrically insulative, highly thermally conductive, low heat capacity substrate where the heater circuit track pattern has a conductive layer and a resistive layer. The conductive layer has conductive parts such that power pads, main power lines, electrical transfer pads, sub-conductor lines are formed by a highly conductive material to distribute power equally to the resistive layer. The resistive layer has resistive portions including resistive parts formed by a resistive ink to heat up the heater plate.