Flash-Treated ITO Coatings for Insulating Glass Units
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Solution Overview
Problem
Existing transparent electrically conductive oxide coatings, particularly indium tin oxide (ITO) films, face challenges in achieving a balance of electrical conductivity, optical properties, and durability when subjected to flash treatment, especially for use on multiple-pane insulating glazing units, where high-power flash treatment is desired to enhance properties like carrier concentration and surface roughness.
Innovation Solution
A method involving ultra-high-power flash treatment of ITO films deposited on glass substrates using sputter deposition, followed by a flash treatment system that applies peak pulse powers of 15 kW/cm² or greater, resulting in films with improved carrier concentration, reduced sheet resistance, and enhanced optical bandgap, while maintaining low sodium concentration and surface roughness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional heat treatment methods (furnace heating, laser irradiation, flame treatment) are used on ITO coatings, then electrical conductivity and optical properties are improved, but the treatment process is time-consuming and energy-intensive
Solution Approach 1:
The patent employs periodic pulsed laser irradiation instead of continuous heating. The laser delivers energy in short, intense pulses that rapidly heat the ITO coating to the required treatment temperature and then allow rapid cooling, significantly reducing the overall treatment time while achieving the desired electrical conductivity and optical properties
Solution Approach 2:
The patent replaces conventional thermal field methods (furnace heating, flame treatment) with a concentrated optical field (pulsed laser). This substitution enables precise spatial and temporal control of the heating process, treating only the coating layer while keeping the substrate cool, thereby reducing treatment time and energy consumption
2Reliability
If high-power flash treatment is applied to ITO films to improve carrier concentration and reduce sheet resistance, then electrical conductivity increases, but visible absorption may increase and optical properties may deteriorate
Solution Approach 1:
The patent systematically optimizes multiple parameters including laser pulse duration, peak power density, number of pulses, and wavelength. By carefully adjusting these parameters, the treatment achieves sufficient carrier concentration enhancement for good electrical conductivity while limiting excessive heating that would cause visible absorption increases and optical property deterioration
Solution Approach 2:
The patent applies just enough laser energy to achieve the desired electrical conductivity improvement without excessive treatment. The pulsed laser delivers sufficient energy to increase carrier concentration and reduce sheet resistance to acceptable levels, but stops before causing significant visible absorption increases, thus achieving partial treatment that balances both electrical and optical requirements
3Productivity
If flash lamp treatment is used to treat large area coatings, then treatment efficiency improves, but the underlying substrate becomes overheated
Solution Approach 1:
The patent uses a pulsed laser with controllable spot size to treat the ITO coating locally. The laser energy is concentrated on the thin coating layer rather than being distributed across the entire substrate, enabling efficient treatment of large areas while maintaining substrate temperature at acceptable levels through selective heating
Solution Approach 2:
The pulsed laser treatment allows repeated cycles of rapid heating and cooling. Each pulse heats the coating briefly to the required temperature, then the coating and substrate cool between pulses. This periodic action enables cumulative treatment effect on the coating while preventing substrate overheating, maintaining treatment efficiency without thermal damage
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 method produces ITO films with increased carrier concentration, reduced sheet resistance, and improved optical properties, such as higher monolithic visible transmittance and lower visible absorption, while maintaining the glass substrate's annealed state and minimizing sodium migration, thus enhancing the performance and durability of the coatings on insulating glazing units.
Implementation Method 1
flash treatment system that applies peak pulse powers of 15 kW/cm² or greater
Implementation Method 2
ITO films deposited on glass substrates using sputter deposition
Implementation Method 3
pre and post flash optical bandgaps enabling good absorption, during the flash, of radiation in the range of 370-400 nm
Implementation Method 4
The resulting film preferably would have surface roughness, carrier concentration, and absorption properties that are particularly advantageous
Data Source
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AI summary
The invention provides flash-treated transparent conductive coatings based on indium tin oxide. Some embodiments provide a multiple-pane insulating glazing unit that includes two glass panes and a between-pane space. The two glass panes respectively define two opposed external pane surfaces. At least one of the two external pane surfaces has a flash-treated transparent conductive oxide coating.