Uniform Heating for Shaped Heaters via Nonparallel Busbars
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Solution Overview
Problem
Existing electrically heated transparent conductive materials for goggles and visors suffer from non-uniform heating, leading to hotspots and inefficiencies due to varying busbar distances, which limits their performance in inclement weather and increases energy consumption.
Innovation Solution
The use of continuous solid state printed busbars with intermittent connections through transparent dielectric materials and varying sheet resistivity, achieved through holes, voids, or dots, to ensure uniform heating across non-parallel busbars, using equations to determine optimal contact and non-contact zones for uniform watt density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If continuous solid state printed busbars with intermittent connections are used, then heating uniformity is improved, but device complexity increases due to dielectric material integration
Solution Approach 1:
A transparent dielectric material is introduced as an intermediary between the busbar and the conductive coating. This dielectric layer is patterned with contact zones (allowing electrical connection) and non-contact zones (creating spacing). The dielectric mediator enables uniform heating by controlling the distance between busbar and coating, while maintaining electrical connectivity where needed. This resolves the contradiction by adding a controlled element that improves heating uniformity without excessive complexity.
2Temperature
If varying sheet resistivity is implemented through holes, voids, or dots, then heating uniformity is improved, but manufacturing precision requirements increase
Solution Approach 1:
The conductive coating is designed with spatially varying sheet resistivity through strategically placed holes, voids, or dots. Areas with higher required heating have lower sheet resistivity (fewer or smaller openings), while areas requiring less heating have higher sheet resistivity (more or larger openings). This local variation in material property achieves uniform heating across the entire surface by compensating for variations in busbar spacing and surface area.
3Adaptability or versatility
If non-parallel busbars are used to cover irregular shapes, then adaptability is improved, but heating uniformity deteriorates due to varying distances
Solution Approach 1:
The sheet resistivity of the conductive coating is locally adjusted to compensate for varying busbar distances. Regions where busbars are closer together have higher sheet resistivity (more holes/voids/dots), while regions where busbars are farther apart have lower sheet resistivity (fewer or smaller holes/voids/dots). This local customization of electrical properties ensures uniform power density and heating across irregularly shaped surfaces with non-parallel busbars.
Solution Approach 2:
The sheet resistivity parameter of the conductive coating is varied spatially to compensate for geometric variations in busbar spacing. By changing this key electrical parameter across different regions of the coating, the system achieves uniform heating despite the non-parallel arrangement of busbars required for irregular surface coverage.
4Use of energy by moving object
If intermittent connections with dielectric material are used, then energy consumption is reduced, but contact reliability may worsen due to potential connection failures
Solution Approach 1:
The transparent dielectric material serves as a controlled intermediary that enables reliable intermittent connections. The dielectric layer is precisely patterned to create contact zones where electrical connection occurs and non-contact zones where spacing is maintained. This controlled mediation through the dielectric layer improves energy efficiency by eliminating unnecessary heating in certain regions while maintaining connection reliability through precise geometric control of contact areas.
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
This approach eliminates hotspots, enhances heating uniformity, reduces energy consumption, and allows for more efficient use of batteries, providing effective defogging and de-icing capabilities while maintaining transparency and durability.
Implementation Method 1
Conductive films using silver nano particles and carbon are available from sources such as Chasm Corporation as alternatives to the ITO. These materials when connected electrically by means of printed silver conductive busbars to a power source can be heated to some design temperature
Implementation Method 2
The present disclosure more specifically is in the field of electrically heating transparent conductive materials with a uniform sheet resistivity for defogging and de-icing various surfaces
Implementation Method 3
These materials when connected electrically by means of printed silver conductive busbars to a power source can be heated to some design temperature, so that snow, ice, or vapor condensation or fogging can evaporate or melt
Data Source
AI summary
A method, equation, system, and device for electrically heating Indium Tin Oxide (ITO) and other transparent conductive materials having a uniform sheet resistivity for defogging and de-icing in a cold environment. The use of nonparallel busbars for connecting the conductive materials reduces excessive and dangerous hot zones. The mathematical analysis and equations provide a means of precisely providing an intermittent electrical connection so that the Watt density and heating is uniform, allowing much higher temperature for de-icing and defogging and more efficient use of energy. This same concept can be used for three dimensional formed heaters to compensate for non uniform sheet resistivity. Also shown are a means of improved busbar designs and an equation and a means of altering sheet resistivity to produce electric heaters with non parallel busbars of various shapes for uniform heating