Sol-Gel Coating Apparatus with Air Knife Curing
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Solution Overview
Problem
Current sol-gel coating techniques face challenges in achieving efficient, cost-effective, and uniform coating on large substrates, particularly in industrial scale applications, due to issues with material control, contamination, and temperature sensitivity, which limits their use on temperature-sensitive materials like fully assembled solar panels.
Innovation Solution
A combination roll coating and curing facility using a conveyor system with an air knife, infrared emitters, and heat applicators to control the temperature and curing process, allowing for selective coating of one substrate face, efficient material use, and uniformity, while maintaining low complexity and cost, and accommodating temperature-sensitive substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dip coating is used to coat large substrates, then complete sol coverage is achieved, but the tank holds large volume of sol posing vapor and flammability hazard
Solution Approach 1:
The coating process is segmented into multiple zones: a coating zone where sol is applied to the substrate, and a separate drying/curing zone. This eliminates the need for a large tank holding volatile sol, as sol is applied locally and immediately processed, reducing vapor hazards while maintaining complete coverage.
Solution Approach 2:
A controlled atmosphere or barrier system is introduced as an intermediary between the sol and the environment, preventing vapor release and flammability hazards while allowing the coating process to proceed with complete coverage.
2Reliability
If dip coating is used for multiple substrates, then complete coverage is maintained, but sol composition varies due to contamination and depletion
Solution Approach 1:
The substrate is extracted from the sol coating process immediately after application, and a fresh sol supply is provided for each substrate. This prevents contamination accumulation and composition depletion that occur when multiple substrates are coated in the same sol bath, maintaining both complete coverage and composition precision.
Solution Approach 2:
The system dynamically adjusts sol flow rate, viscosity, and other parameters for each coating cycle based on real-time measurements, ensuring consistent composition and complete coverage even when processing multiple substrates sequentially.
3Reliability
If conventional curing methods are used, then coating is cured, but temperature-sensitive substrates are damaged
Solution Approach 1:
Conventional thermal curing is replaced with alternative curing mechanisms such as photopolymerization using UV or visible light, or chemical curing at ambient temperature. This substitutes the mechanical/thermal system with optical or chemical systems that achieve coating cure without damaging temperature-sensitive substrates.
Solution Approach 2:
The curing process parameters are changed from high temperature to ambient or low temperature conditions, utilizing catalysts, light activation, or chemical reactions that enable curing without thermal damage to sensitive substrates.
4Area of stationary object
If spray coating is used for wide area coverage, then uniform layer is deposited, but equipment complexity increases for substrate movement
Solution Approach 1:
Instead of moving the substrate through stationary spray nozzles, the system inverts the approach by bringing the spray coating head to the substrate or using a stationary coating zone where the substrate is fed through. This reduces the complexity of substrate movement control while maintaining wide area coverage and uniform deposition.
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 enables superior coating uniformity and curing of sol-gel coatings on substrates with controlled temperature profiles, achieving desired mechanical and optical properties without damaging the substrate, and is compatible with various sol-gel formulations and equipment.
Implementation Method 1
an air knife adapted to direct heated air to a portion of the flat substrate as it is transported through the at least one curing facility
Implementation Method 2
an infrared emitter adapted to heat the substantially flat substrate to a temperature of between 25° C. to 200° C.
Implementation Method 3
Thin-film sol-gel coating refers to a technique of coating substrates using a wet chemical formulation called a 'sol' that undergoes a 'gelation' process wherein it polymerizes to form a solid thin-film on a substrate
Data Source
AI summary
Disclosed is a coating apparatus including flow coating and roll-coating that may be used for uniform sol-gel coating of substrates such as glass, solar panels, windows or part of an electronic display. Also disclosed are methods for substrate preparation, flow coating and roll coating. Lastly, systems and methods for curing sol-gel coatings deposited onto the surface of glass substrates using high temperature air-knives, infrared emitters and direct heat applicators are disclosed.