Optical Module Stepped Vent Seal for Hermetic Bonding
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Solution Overview
Problem
In high-speed data communication, optical modules face challenges in maintaining a stable and hermetic seal during the heating process of bonding components, as expanded gases can push the cover apart before the glue solidifies, potentially damaging the internal optical components.
Innovation Solution
The optical module design includes vent holes with sealing members featuring a stepped structure, allowing gas expansion to escape while ensuring a tight seal, and using a protective gas atmosphere to prevent oxidation and moisture ingress, ensuring the cover and housing remain securely connected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If vent holes are provided to allow gas expansion during heating, then the cover can remain securely connected, but the hermetic seal is compromised
Solution Approach 1:
The vent hole is segmented into two parts: a first portion with a larger aperture and a second portion with a smaller aperture. This segmentation allows the vent hole to serve dual functions: the larger first portion allows gas to escape during heating to prevent cover displacement, while the smaller second portion maintains a hermetic seal during normal operation. The stepped structure creates different flow resistance at different stages of the vent hole, resolving the contradiction between needing gas escape paths and maintaining seal integrity.
2Reliability
If the housing is sealed hermetically, then optical components are protected from oxidation, but gas expansion during heating can push the cover apart
Solution Approach 1:
The stepped vent hole structure is pre-designed with specific aperture dimensions before the bonding process. The first portion with the larger aperture is positioned to allow gas escape during the heating process, preventing pressure buildup that would otherwise push the cover apart. This preliminary structural arrangement ensures that during the bonding operation, gas can escape through the vent hole while the stepped design maintains a hermetic seal during normal operation, thus protecting optical components from oxidation.
3Strength
If the vent hole has a large aperture for gas escape, then cover displacement is prevented, but the hermetic seal is compromised and oxidation can occur
Solution Approach 1:
Different portions of the vent hole have different aperture sizes to serve different functions. The first portion has a larger aperture optimized for gas escape during heating to prevent cover displacement, while the second portion has a smaller aperture optimized for maintaining hermetic seal during normal operation to prevent oxidation. This local differentiation of quality (aperture size) at different locations within the vent hole structure allows simultaneous achievement of both gas escape and oxidation protection.
Data Source
AI summary
An optical module includes a housing, at least one optical assembly and at least one sealing member. The housing includes a housing body, a cover and at least one vent hole therein. At least part of each optical assembly is located in the housing body. Each sealing member is located at a respective one of the at least one vent hole. The sealing member has a central axis and includes a first cylinder, a truncated cone, and a second cylinder, a diameter of the first cylinder is greater than a diameter of the second cylinder. Each vent hole is a stepped hole including a portion with a first aperture and a portion with a second aperture, the first aperture is greater than the second aperture. The first cylinder fits the portion with the first aperture, and the second cylinder fits the portion with the second aperture.