Silver Thin Layer Crystallization via Localized Laser Heating
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Solution Overview
Problem
Existing methods for depositing thin silver layers on glass substrates, such as the magnetron process, often result in amorphous or nano-crystallized layers due to low substrate temperatures, which hinder crystallization and require costly and risky heat treatments to achieve desired properties, leading to potential substrate breakage and inefficiencies in industrial production.
Innovation Solution
A method that selectively heats the thin silver layers to temperatures above 300°C in a controlled manner, using high-power heating techniques like induction, infrared lasers, or plasma torches, while maintaining the substrate at a lower temperature to prevent breakage, promoting crystallization without altering the layer's thickness or refractive indices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the substrate is heated to high temperatures during or after deposition to promote crystallization, then the crystallization rate and grain size of the silver layer improve, but the substrate is at risk of breakage and the process complexity increases
Solution Approach 1:
The patent applies local heating to specifically heat the silver layer while minimizing substrate heating. The laser beam is focused on the silver layer to create a localized temperature increase that promotes crystallization without subjecting the entire substrate to high temperatures that would cause breakage.
Solution Approach 2:
The patent replaces conventional thermal field assistance (which heats the entire substrate) with laser field assistance that provides localized energy. This substitution allows precise control of heating zones, enabling crystallization promotion while avoiding substrate-wide thermal stress and breakage.
2Manufacturing precision
If conventional thermal field assistance is used to promote crystallization, then the silver layer crystallizes better, but the heating is indiscriminate and causes substrate breakage
Solution Approach 1:
The laser beam is focused on the silver layer to create a localized temperature increase that promotes crystallization without subjecting the entire substrate to high temperatures that would cause breakage.
Solution Approach 2:
The patent replaces conventional thermal field assistance with laser field assistance, enabling precise control of heating zones and avoiding indiscriminate substrate heating that leads to breakage.
3Productivity
If the substrate temperature is kept low during magnetron deposition for economic reasons, then production speed and cost are optimized, but the silver layer remains amorphous or nano-crystallized with inferior properties
Solution Approach 1:
The patent applies laser annealing after the magnetron deposition process to promote crystallization. This preliminary crystallization step is performed on the already-deposited layer, allowing the deposition to occur at low temperatures for efficiency, followed by localized laser heating to achieve the desired crystalline structure.
Solution Approach 2:
The patent uses laser field assistance instead of thermal field assistance to promote crystallization. This allows crystallization to occur after deposition without requiring the substrate to be heated during the deposition process itself, maintaining production efficiency while achieving better layer properties.
4Manufacturing precision
If heat treatment is applied after deposition to achieve desired crystallization, then the silver layer properties improve, but the process time increases and production slows down
Solution Approach 1:
The patent replaces conventional thermal field assistance with laser field assistance, enabling rapid and localized heating that promotes crystallization much faster than conventional methods. The laser can be moved along the substrate, treating large areas quickly without requiring the entire substrate to be heated and cooled slowly.
Solution Approach 2:
The laser annealing process can be performed continuously as the laser beam moves across the substrate, maintaining productive action throughout the treatment process rather than requiring batch processing with heating and cooling cycles.
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 method significantly increases the crystallization rate of silver layers to over 20%, improving electrical conductivity and low emissivity properties while maintaining the substrate's integrity, allowing for continuous industrial production without the need for tempering or slow cooling processes.
Implementation Method 1
heating of the thin layer can be carried out using radiation whose wavelength is included in said part of the infrared radiation absorbed by said layer
Implementation Method 2
Heating of the thin layer can be carried out by induction
Implementation Method 3
at least partial crystallization of said thin layers
Data Source
AI summary
The invention relates to a method for processing at least one continuous thin layer deposited on the first surface of a substrate, characterised in that said at least one thin layer is heated at a temperature of at least 300°C while maintaining a temperature lower than or equal to 150°C at the surface of said substrate opposite said first surface in order to increase the crystallisation rate of said thin layer while maintaining it continuous and without any fusion step of said thin layer. The invention also relates to a material that can be obtained using said method.