Thin-Lid Hermetic Optical Package for Welding Stress Control
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Solution Overview
Problem
Conventional hermetic packages with large lids made from thick materials experience cracking and bowing due to stress induced by the welding process, compromising hermeticity and optical alignment.
Innovation Solution
Implementing a hermetic package with a thin lid, having an average thickness of less than 150 μm, to reduce stress and deformation, thereby minimizing package cracking and bowing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a thick lid is used for a large hermetic package, then the lid provides robustness and limits deflection during production processes, but the package experiences cracking and bowing due to stress induced by the welding process
Solution Approach 1:
The patent changes the thickness parameter of the lid from conventional thick (0.254 mm) to thin (less than 150 μm average thickness). This parameter change reduces the stress induced during welding while maintaining sufficient structural integrity through optimized material selection and welding process control, thereby preventing cracking and bowing that compromise hermeticity
Solution Approach 2:
The patent applies different thickness characteristics to different regions of the lid. The lid features a thin interior region (less than 150 μm) that minimizes welding stress, while maintaining adequate edge thickness for proper sealing. This local differentiation allows the lid to be robust where needed while minimizing overall stress during the welding process
2Strength
If a thick lid is used for a large hermetic package, then the lid provides structural integrity, but the package surface experiences bowing that compromises optical alignment
Solution Approach 1:
By changing the lid thickness parameter to less than 150 μm average thickness, the patent reduces the thermal mass and stress accumulation during welding. This minimizes surface bowing of the package, thereby maintaining the precision required for optical alignment while still providing sufficient structural integrity through controlled material properties and welding parameters
3Reliability
If a thin lid is used for a large hermetic package, then package stress is reduced and hermeticity is enhanced, but the lid may lack sufficient robustness
Solution Approach 1:
The patent optimizes the lid thickness parameter to less than 150 μm, which is thin enough to reduce welding-induced stress and enhance hermeticity by preventing cracks, yet sufficient to maintain robustness when combined with appropriate material selection and controlled welding processes. This parameter optimization resolves the apparent contradiction between thinness for stress reduction and sufficient thickness for structural integrity
Solution Approach 2:
The patent may employ composite material structures or material combinations that provide high strength-to-thickness ratios. By using materials with optimized mechanical properties, the lid achieves sufficient robustness at reduced thickness, allowing stress reduction and hermeticity enhancement without sacrificing structural integrity
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 use of a thin lid reduces stress in the package, enhancing hermeticity and optical alignment by minimizing wall displacement and surface bowing, while maintaining package integrity and functionality.
Implementation Method 1
a deformed package lid affixed to the plurality of walls and over the cavity, wherein an average thickness of the deformed package lid is less than approximately 150 micrometers (μm)
Data Source
AI summary
A hermetic optical package may include a package body comprising a surface and a plurality of walls. The surface and the plurality of walls may form a cavity. A smallest lateral dimension of the package body may be greater than approximately 7 millimeters (mm). The hermetic optical package may include one or more components mounted on the surface and within the cavity. The hermetic optical package may include a deformed package lid affixed to the plurality of walls and over the cavity. An average thickness of the deformed package lid may be less than approximately 150 micrometers (μm).