Solid-State Light Source UV Curing with Inert Gas Flow
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Solution Overview
Problem
Industrial processes, such as UV curing of adhesives and coatings, face challenges due to oxygen inhibition, which leads to incomplete curing and thermal loading issues, especially in manufacturing optical storage media like CDs/DVDs, where immersion inerting is impractical and unsafe, and conventional methods are costly and complex.
Innovation Solution
A system and method that utilize a fluid flow of inert gases like nitrogen to create an oxygen-free environment at specific surfaces during photoreactions, using a solid-state light source and precise fluid flow control to mitigate oxygen inhibition and thermal issues, ensuring complete curing without turbulence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If immersion inerting is used to remove oxygen during UV curing, then complete curing is achieved, but the process becomes unsafe and impractical for manufacturing optical storage media
Solution Approach 1:
The patent divides the curing environment into two distinct zones: an oxygen-free zone where UV light initiates polymerization, and an oxygen-present zone that prevents oxygen inhibition. This segmentation allows the system to achieve complete curing without requiring full immersion inerting, making the process safe and practical for manufacturing optical storage media.
Solution Approach 2:
The patent applies local quality by creating an oxygen-free environment only at the specific location where UV curing occurs (the work surface), rather than throughout the entire manufacturing space. This localized approach maintains safety and practicality while ensuring complete curing where needed.
2Reliability
If conventional inerting methods are used to prevent oxygen inhibition, then curing quality improves, but cost and system complexity increase
Solution Approach 1:
The patent extracts oxygen from the immediate vicinity of the work surface using a fluid flow system, removing only the specific harmful element (oxygen) from the localized curing zone rather than implementing a comprehensive inerting system. This reduces system complexity and cost while maintaining curing quality.
Solution Approach 2:
The patent introduces a fluid flow as an intermediary medium that carries oxygen away from the work surface. This intermediary approach simplifies the system compared to direct inerting methods, as the fluid flow can be easily controlled and managed without requiring complex inert gas distribution systems.
3Productivity
If high UV light intensity is applied to cure coatings quickly, then productivity increases, but thermal loading and undesirable heating occur
Solution Approach 1:
The patent converts the harmful effect of oxygen absorption (which causes undesirable heating) into a beneficial outcome by removing oxygen from the curing zone. This allows high UV light intensity to be applied for fast curing without the penalty of thermal loading, as the oxygen that would otherwise absorb energy and generate heat is eliminated from the system.
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 enables effective curing of UV-curable materials by maintaining an inert atmosphere at the edges of rotating CDs/DVDs, preventing tacky edges and thermal distortions, while being cost-effective and safe for human access, with controlled fluid flow ensuring efficient energy distribution and complete polymerization.
Implementation Method 1
UV curing of adhesives and coatings
Implementation Method 2
The presence of oxygen during the UV cure process can have a detrimental effect on the cure response of free radical systems. Oxygen reacts with the free radical and forms peroxy radicals by reaction with the photoinitiator, monomer or propagating chain radical. The reactivity of the peroxy radicals is insufficient to continue the free radical polymerization process, leading to chain termination and an under cured system.
Data Source
AI summary
System and methods are disclosed in connection with a reaction at or below the surface of a work object, in the context of a fluid flow fostering the reaction. In some example embodiments, the reaction is fostered by (1) creating fluid flow of an inerting fluid over a surface during exposure of the surface to a predetermined type of light, (2) creating fluid flow comprising a reactive species that reacts with another species at or below the work surface in a predetermined manner and/or (3) creating a fluid flow comprising a catalytic species that catalyzes a reaction in a predetermined manner, e.g., during exposure of the surface to a predetermined type of light. In some example embodiments, a light source is employed that comprises a solid-state light source, e.g., a dense array of solid-state light sources. In at least one of such example embodiments, the reaction is a photoreaction associated with the light source.