Transparent Heaters Using Embedded Micro-Wires
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Solution Overview
Problem
Existing transparent film heaters face challenges with non-uniform power density, visibility issues due to wire size, and costly fabrication methods, particularly with continuous conductive sheets and wire-based heaters, which are either too large to be invisible or inefficient for heating applications.
Innovation Solution
A transparent heater design featuring high aspect ratio micro-wires with widths between 4 and 9 microns and depths at least 1.5 times the width, embedded in a substrate, allowing for low-cost roll-to-roll manufacturing and high optical transmittance, enabling efficient heating while being virtually invisible.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional wire-based heaters are used, then heating function is achieved, but wires are visible to human observers
Solution Approach 1:
The patent transitions from conventional 2D surface-mounted wires to 3D embedded micro-wires within the substrate thickness. By utilizing the third dimension (depth), the wires achieve a width of 4-9 microns while maintaining sufficient cross-sectional area for heating, making them substantially invisible to the naked eye while preserving the heating function.
Solution Approach 2:
The patent creates localized high-aspect-ratio micro-wire structures embedded within the substrate at specific locations where heating is needed. These micro-wires have different dimensional characteristics (narrow width, sufficient depth) compared to conventional wires, providing both invisibility and adequate heating performance in the critical visible region.
2Illumination intensity
If continuous conductive sheets are used, then transparency is maintained, but power density becomes non-uniform
Solution Approach 1:
The patent divides the continuous conductive sheet into discrete, spatially separated micro-wire elements embedded in the substrate. This segmentation allows each micro-wire to be independently positioned and sized, enabling uniform power density distribution across the heating area while maintaining overall transparency through the spaced arrangement of individual wire elements.
3Illumination intensity
If micro-wire width is reduced for invisibility, then transparency improves, but power capacity decreases
Solution Approach 1:
The patent compensates for the reduced width (4-9 microns) by increasing the aspect ratio through greater depth/embedded dimension within the substrate. This dimensional transition allows the micro-wires to maintain adequate cross-sectional area and electrical conductivity for heating while presenting a narrow profile that is substantially invisible to the naked eye.
Solution Approach 2:
The patent employs composite micro-wire structures with high-aspect-ratio geometries, combining narrow width for transparency with sufficient embedded depth for power capacity. This composite dimensional approach enables the micro-wires to simultaneously achieve optical invisibility and adequate heating performance.
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 provides uniform power density and high optical transmittance, allowing the heater to be virtually invisible and effective for applications requiring transparency, such as display surfaces, while maintaining a flat surface and increased power capacity compared to conventional micro-wires.
Implementation Method 1
a plurality of micro-wires formed by at least partially filling the channels with a conductive material
Implementation Method 2
wherein an average optical transmittance of the transparent heater within the active heater region is greater than 50 percent
Data Source
AI summary
A transparent heater includes a plurality of high aspect ratio micro-wires. A plurality of channels is formed into the surface of a transparent substrate within an active heater region. The channels have a width of between 4 microns and 9 microns to insure that they are invisible to the naked eye, and a depth that is at least 1.5 times the width. Spacing between the channels is preferably at least 100 μm. Micro-wires are formed by at least partially filling the channels with a conductive material. Power source connections are provided to connect to an electrical power source to supply a current through the plurality of micro-wires. An average optical transmittance of the transparent heater within the active heater region is greater than 50 percent.