Micro-bead Blasting for LED Lens Silicone Flash Removal
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Solution Overview
Problem
Compression molding for forming lenses over LED arrays on printed circuit boards results in a silicone flash layer that covers contact pads, preventing electrical contact and requiring inefficient and costly methods for removal, such as manual scraping or taping, which can damage the pads or lenses.
Innovation Solution
A micro-bead blasting process using abrasive particles in a high-pressure air stream to remove the silicone flash layer, with particles like sodium bicarbonate or silicon dioxide, directed at an angle to target the flash layer above contact pads, ensuring removal without damaging the pads or lenses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If compression molding is used to form lenses over LED arrays, then lens quality is improved and material waste is reduced, but a silicone flash layer covers the contact pads preventing electrical contact
Solution Approach 1:
The patent segments the flash layer removal process into a controlled blasting operation that selectively removes silicone only from contact pad areas while preserving the lens structure. The process divides the treatment zone into target areas (contact pads) and non-target areas (lenses), applying abrasive particles only where needed to expose electrical contacts without compromising lens integrity.
Solution Approach 2:
The patent extracts the flash layer silicone from the contact pad regions through micro-bead blasting, separating the unwanted silicone material from the functional contact areas. This extraction process removes only the necessary portion of the flash layer while leaving the lens and other critical structures intact, enabling subsequent electrical contact operations.
2Ease of operation
If manual scraping or taping methods are used to remove the flash layer, then electrical contact is restored, but the contact pads or lenses may be damaged and process costs increase
Solution Approach 1:
The patent replaces manual mechanical scraping and taping methods with a controlled micro-bead blasting process. Instead of using hand tools that require significant force and risk damaging delicate structures, the system uses a stream of abrasive particles delivered through compressed air, providing precise, controlled material removal that protects both contact pads and lenses from damage.
Solution Approach 2:
The patent employs pneumatic technology by using compressed air to deliver a stream of abrasive micro-beads to the flash layer. This pneumatic delivery system provides controlled, consistent force for silicone removal without the mechanical contact and potential damage associated with manual scraping tools, while maintaining precision through adjustable air pressure and particle flow.
3Productivity
If conventional deflashing methods are used, then the flash layer is removed, but material waste increases and process efficiency decreases
Solution Approach 1:
The patent extracts only the necessary portion of the flash layer silicone from contact pad areas through targeted micro-bead blasting, rather than removing entire lenses or large portions of silicone. This selective extraction minimizes material waste while achieving the required electrical contact accessibility, improving both productivity and material efficiency.
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
Effectively removes the silicone flash layer without damaging the contact pads or lenses, allowing for efficient electrical connectivity and reducing material waste and process costs, while maintaining lens quality.
Implementation Method 1
a stream of abrasive particles is directed at the silicone flash layer such that the particles collide into the flash layer
Implementation Method 2
the particles collide into the flash layer until the flash layer laterally above the contact pads is removed
Data Source
AI summary
Using compression molding to form lenses over LED arrays on a metal core printed circuit board leaves a flash layer of silicone covering the contact pads that are later required to connect the arrays to power. A method for removing the flash layer involves blasting particles of sodium bicarbonate at the flash layer. A nozzle is positioned within thirty millimeters of the top surface of the flash layer. The stream of air that exits from the nozzle is directed towards the top surface at an angle between five and thirty degrees away from normal to the top surface. The particles of sodium bicarbonate are added to the stream of air and then collide into the top surface of the silicone flash layer until the flash layer laterally above the contact pads is removed. The edge of silicone around the cleaned contact pad thereafter contains a trace amount of sodium bicarbonate.