Integrated CTE-Flex Coupler for Reliable Epoxy Window Seals
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Solution Overview
Problem
The significant coefficient of thermal expansion (CTE) mismatch between the package body and the window in opto-mechanical packages, particularly when using aluminum for the body and glass for the window, leads to unreliable epoxy seals due to differing expansion and contraction, especially at colder temperatures, compromising the reliability of the opto-mechanical device.
Innovation Solution
An integrated CTE-flex coupler with a flexible element is used to create a compressive epoxy seal, featuring a CTE step between the package body and window, allowing for the use of low-cost materials like aluminum and glass, while eliminating the need for expensive metal plating, and reducing stress on the epoxy joints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If aluminum package body and glass window are used, then cost is reduced, but seal reliability deteriorates due to CTE mismatch
Solution Approach 1:
A coupler component is introduced as an intermediary element between the aluminum package body and glass window. The coupler has a CTE value intermediate between aluminum and glass, creating a CTE gradient that reduces thermal stress at the epoxy joints. This mediator allows the use of low-cost aluminum and glass materials while maintaining seal reliability through progressive CTE transition.
Solution Approach 2:
The invention changes the CTE parameter distribution by introducing a coupler with intermediate CTE properties. Instead of direct contact between high-CTE aluminum and low-CTE glass, the system creates a staged CTE transition (aluminum > coupler > glass), which modifies the stress distribution and prevents epoxy seal failure during thermal cycling.
2Reliability
If CTE-matched materials are used for package body and window, then seal reliability is improved, but cost increases due to expensive metal plating
Solution Approach 1:
The invention replaces expensive CTE-matched metal-plated materials with a cost-effective coupler component that achieves similar reliability functions. The coupler uses inexpensive materials with appropriate CTE properties to create the necessary thermal expansion gradient, eliminating the need for costly metal plating while maintaining seal integrity.
Solution Approach 2:
The coupler may be constructed from composite materials or metal alloys engineered to have intermediate CTE values between aluminum and glass. This composite approach allows precise control of thermal expansion properties at low cost, providing the necessary CTE transition without expensive traditional CTE-matched materials.
3Manufacturing precision
If rigid structure is used, then manufacturing precision is improved, but stress on epoxy joints increases at temperature changes
Solution Approach 1:
The invention modifies the structural rigidity parameter by introducing a coupler that provides both dimensional stability for manufacturing precision and controlled flexibility to accommodate thermal expansion differences. The coupler's intermediate CTE and structural design allow it to maintain geometric stability while reducing stress transmission to epoxy joints during thermal cycling.
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 CTE-flex coupler enhances seal reliability and hermeticity by providing compressive stress on the epoxy joints, maintaining a reliable seal across temperature changes, thus increasing the overall reliability of the opto-mechanical device.
Implementation Method 1
the coupler comprises a flexible element associated with providing stress reduction
Implementation Method 2
a coefficient of thermal expansion (CTE) of a material of the coupler is less than a CTE of a material of the package body; a CTE of a material of the window is less than the CTE of the material of the coupler
Data Source
AI summary
An opto-mechanical package may include a package body having a first opening. The opto-mechanical package may include a coupler in the first opening of the package body. The coupler may have a second opening. The coupler may comprise a flexible element. A coefficient of thermal expansion (CTE) of a material of the coupler may be less than a CTE of a material of the package body. The opto-mechanical package may include a window in the second opening of the coupler. A CTE of a material of the window may be less than the CTE of the material of the coupler. The opto-mechanical package may include a first epoxy joint between a surface of the package body and a surface of the coupler. The opto-mechanical package may include a second epoxy joint between a surface of the coupler and a surface of the window.