Planar Heat-Generating Element with Optimized Hole Array
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Solution Overview
Problem
Planar heat-generating elements with heat-generating layers suffer from temperature unevenness due to the detour of current around holes, leading to reduced heating efficiency and potential material degradation, and multilayer configurations increase power consumption.
Innovation Solution
A planar heat-generating element with a heat-generating layer having holes, where the electrodes are arranged to oppose each other and the base material and protective layer are connected to the holes, with specific relationships between hole widths and intervals to minimize current detour and temperature unevenness, and a polyimide-based configuration with varying imidation ratios for the protective layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If holes are formed in the heat-generating layer for fixing members or shape matching, then the contact surface stability is improved, but temperature unevenness occurs in the heating surface
Solution Approach 1:
The patent applies parameter changes by establishing specific mathematical relationships between hole dimensions and spacing. The hole width w must satisfy w ≤ D/3 where D is the interval between adjacent holes, and the hole area ratio must be within 1-20% of the total heat-generating layer area. These parameter optimizations ensure that current detour paths remain sufficiently wide to maintain uniform current density while still providing adequate holes for mechanical fixation, thus resolving the contradiction between contact stability and temperature uniformity
2Productivity
If multiple heat-generating layers are laminated to increase hot air generation efficiency, then the heating efficiency is improved, but power consumption increases
Solution Approach 1:
The patent utilizes porous materials by forming an optimized array of holes directly in the heat-generating layer itself, creating a porous structure that allows hot air to pass through efficiently. This single-layer porous approach eliminates the need for multiple laminated layers, achieving high hot air generation efficiency while maintaining lower power consumption compared to multilayer configurations
3Device complexity
If the heat-generating layer uses a linear heat-generating source, then the structure is simple, but the heat-generating area is limited and temperature unevenness occurs
Solution Approach 1:
The patent transitions from a one-dimensional linear heat-generating source to a two-dimensional planar heat-generating layer with distributed holes. This dimensional expansion significantly increases the effective heat-generating area while maintaining structural simplicity, as the planar configuration allows heat to be generated across the entire surface area rather than along a linear path
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 reduces temperature unevenness and enhances heating efficiency by optimizing current flow and heat distribution, while also reducing power consumption and material stress.
Implementation Method 1
Energization from the electrodes causes a current to flow through the heat-generating element, resulting in an increase in temperature of the heat-generating element through resistance heating
Data Source
AI summary
The planar heat-generating element includes: a base material; a heat-generating layer formed on the base material, the heat-generating layer having conductivity; a pair of electrodes arranged to be brought into contact with the heat-generating layer; and a protective layer, wherein the pair of electrodes are arranged so as to be opposed to each other in a direction parallel to a first direction, wherein the heat-generating layer has a plurality of holes in a region between the pair of electrodes, wherein, when widths of two holes out of the plurality of holes in a second direction orthogonal to the first direction, the two holes being present adjacent to each other on one and the same straight line parallel to the second direction and an interval between the two holes in a direction parallel to the second direction satisfy a specific relationship.