Laser Bonding Optical Elements to Substrates
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Solution Overview
Problem
High coefficient of thermal expansion (CTE) adhesives used to secure optical elements to substrates cause misalignment during elevated temperature processes, such as solder reflow, due to thermal expansion, disrupting optical communication.
Innovation Solution
A laser welding process that uses a curved optical element to focus a laser beam onto a substrate, melting and bonding the substrate material without the need for high CTE adhesives, ensuring stable alignment of optical elements at elevated temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high CTE adhesive is used to secure optical elements to substrate, then optical elements are fixed to substrate, but optical elements shift position during elevated temperature processes causing misalignment
Solution Approach 1:
The patent changes the bonding method from adhesive-based to laser welding-based, fundamentally altering the bonding parameters. Laser welding creates a metallurgical bond without requiring adhesive materials that have high CTE, thus eliminating the root cause of thermal expansion-induced misalignment while maintaining strong bonding
Solution Approach 2:
The patent replaces the mechanical/adhesive bonding system with a thermal/laser welding system. Instead of using adhesive materials that expand thermally, the invention uses laser-induced melting and fusion to create a permanent bond that is insensitive to thermal expansion, thereby resolving the contradiction between bonding strength and alignment precision
2Ease of manufacture
If adhesive bonding is used to secure optical elements, then optical elements are attached to substrate, but alignment is lost during solder reflow process
Solution Approach 1:
The patent transforms the bonding process from a multi-step adhesive application and curing process to a single-step laser welding process. This parameter change eliminates the need for adhesives that fail during solder reflow, achieving both manufacturing simplicity and alignment stability through direct laser-induced bonding
Solution Approach 2:
The invention replaces the chemical adhesive bonding mechanism with a physical laser welding mechanism. The laser welding process creates a direct metallurgical bond between the optical element and substrate that remains stable during subsequent solder reflow processes, thereby improving reliability without compromising ease of manufacture
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 laser welding process maintains precise alignment of optical elements during high-temperature processes, preventing misalignment and ensuring effective optical communication by eliminating the need for high CTE adhesives.
Implementation Method 1
The film layer is capable of absorbing a wavelength of the laser beam to melt the material of the substrate at the bond area
Implementation Method 2
the optical element is a curved element, such as a GRIN lens, a micro-lens or an optical fiber, that acts as a cylindrical lens to focus the laser beam into the substrate
Implementation Method 3
The focused laser beam melts the substrate material, which also causes the melted substrate material to diffuse into the material of the optical element
Implementation Method 4
the focused laser beam melts the substrate material, which also causes the melted substrate material to diffuse into the material of the optical element
Data Source
AI summary
Assemblies, optical connectors, and methods for bonding optical elements to a substrate using a laser beam are disclosed. In one embodiment, a method of bonding an optical element to a substrate includes disposing a film layer on a surface of the substrate, disposing the optical element on a surface of the film layer, and directing a laser beam into the optical element. The method further includes melting, using the diameter laser beam, a material of the substrate to create a bond area between the optical element and the surface of the substrate. The film layer is capable of absorbing a wavelength of the laser beam to melt the material of the substrate at the bond area. The bond area includes laser-melted material of the substrate that bonds the optical element to the substrate.