Flashlamp Drying of Thin Films Using Composite Pulses
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Solution Overview
Problem
Inexpensive substrates used for thin films, such as polyethylene terephthalate, have lower maximum working temperatures, leading to longer drying times and increased energy costs due to thermally driven processes being exponentially related to processing temperature, making existing drying methods inefficient.
Innovation Solution
A composite light pulse from a flashlamp is used to thermally process thin films, consisting of multiple micropulses that heat the films quickly and efficiently, with the pulse duration shorter than the thermal equilibration time of the stack, allowing for temperatures beyond the substrate's maximum working temperature without damaging it, and a conveyance system ensures the substrate moves less than 10% of the irradiating area during pulse delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional thermal drying methods are used on inexpensive substrates, then substrate cost is reduced, but drying time increases and energy consumption increases
Solution Approach 1:
The patent applies periodic pulsed irradiation instead of continuous heating, using multiple light pulses with specific time intervals to achieve cumulative thermal effect while maintaining substrate temperature within safe limits. This resolves the contradiction by enabling thorough drying without excessive time loss.
Solution Approach 2:
The patent changes the temperature parameter dynamically through controlled pulsed irradiation, achieving high peak temperatures for effective drying while maintaining average temperature within substrate tolerance. This allows inexpensive substrates to be dried efficiently without degradation.
2Ease of manufacture
If conventional thermal drying methods are used on inexpensive substrates, then substrate cost is reduced, but energy consumption increases
Solution Approach 1:
The periodic pulsed irradiation method concentrates energy delivery into specific time intervals, achieving cumulative heating effect with less total energy compared to continuous heating. This resolves the energy consumption issue while maintaining substrate integrity.
Solution Approach 2:
The patent replaces conventional thermal conduction heating with optical radiation heating, which directly heats the thin film and substrate surface more efficiently. This substitution reduces energy loss and improves drying efficiency on inexpensive substrates.
3Loss of time
If higher temperatures are used to reduce drying time, then drying time is reduced, but substrate damage occurs
Solution Approach 1:
The periodic pulsed irradiation allows the substrate to experience high peak temperatures for brief intervals followed by cooling periods, achieving effective drying temperatures without sustained thermal damage. This resolves the contradiction between drying speed and substrate safety.
Solution Approach 2:
The patent incorporates cooling intervals between pulses that allow the substrate to recover and dissipate excess heat, preventing cumulative thermal damage while maintaining drying effectiveness. This cushioning approach protects the substrate from harmful temperature effects.
4Power
If continuous irradiation is used to heat thin films, then heating efficiency is improved, but substrate temperature exceeds maximum working temperature
Solution Approach 1:
The periodic pulsed irradiation delivers high power during pulse intervals while allowing cooling between pulses, achieving effective heating without sustained temperature exceedance. This resolves the contradiction between heating efficiency and temperature control.
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 reduces drying time and energy consumption while maintaining substrate integrity, allowing for efficient thermal processing of thin films on inexpensive substrates with the same amount of radiant energy, preventing cohesive failures and achieving uniform curing over extended distances.
Implementation Method 1
the thin film stack is irradiated with a composite light pulse from the flashlamp
Implementation Method 2
the thin film stack is irradiated with a composite light pulse from the flashlamp during which the thin film stack is heated
Implementation Method 3
the total thermal equilibration time of the thin film stack
Data Source
AI summary
A method for drying a thin film stack having a thin film located on a substrate is disclosed. The thin film stack is conveyed past a flashlamp during which the thin film stack is irradiated with a composite light pulse from the flashlamp. The composite light pulse is composed of multiple micropulses. The time duration of the composite light pulse is shorter than a total thermal equilibration time of the thin film stack. In addition, when the thin film stack is being conveyed past the flashlamp, the thin film stack should move less than 10% of the length of the irradiating area in the conveyance direction during the delivery of the composite light pulse.