Optical Module Lid Seam Welding With a Heat-Sink Block
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Solution Overview
Problem
The existing method of seam welding a metal lid to a ceramic package in optical modules results in significant thermal deformation of the package, leading to reduced coupling efficiency and potential leakage due to residual stress and warping.
Innovation Solution
A metal block is placed on the lid during seam welding to dissipate Joule heat, reducing thermal expansion and residual stress, thereby minimizing package deformation and ensuring hermetic sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If seam welding is performed to join the lid to the package, then hermetic sealing is achieved, but significant thermal deformation and warping of the package occurs
Solution Approach 1:
A copper block is introduced as an intermediary heat dissipation component placed in contact with the lid during welding. This copper block acts as a heat sink, absorbing excess Joule heat generated during seam welding and preventing it from transferring to the package, thereby eliminating warping while maintaining hermetic sealing
Solution Approach 2:
The thermal parameters of the welding process are modified by introducing the copper block with specific thermal properties (high thermal conductivity and heat capacity). This changes the heat distribution pattern, concentrating heat at the weld zone while rapidly dissipating excess heat, thus controlling the thermal field to prevent package deformation
2Reliability
If seam welding is performed to join the lid to the package, then hermetic sealing is achieved, but residual stress and leakage occur
Solution Approach 1:
The copper block serves as a heat sink intermediary that absorbs excess thermal energy during welding, preventing thermal runaway and excessive temperature rise. This control of thermal parameters reduces residual stress in the welded structure, preventing stress-induced leakage while maintaining hermetic sealing integrity
Solution Approach 2:
The copper block is positioned beforehand on the lid to provide thermal cushioning during the welding process. It absorbs and dissipates heat in real-time, preventing excessive temperature accumulation that would lead to residual stress and potential leakage, thus cushioning against harmful thermal effects
3Strength
If the lid is heated to high temperature during welding, then welding is achieved, but thermal expansion and deformation occur
Solution Approach 1:
The copper block acts as a heat sink intermediary placed in contact with the lid. It absorbs excess Joule heat generated during welding and rapidly dissipates it, localizing the high temperature zone to only the weld area while preventing overall thermal expansion of the lid and package, thus achieving strong welding joints without deformation
Solution Approach 2:
The copper block creates a localized thermal management system where heat is concentrated only at the weld zone (where it is needed for joining) while the rest of the lid and package remain relatively cool. This local quality approach ensures welding strength is achieved at the joint without causing global thermal expansion and deformation
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 method effectively suppresses package warping and maintains optical signal coupling efficiency by controlling temperature rise and residual stress during seam welding.
Implementation Method 1
By pressing the roller electrode, a voltage is applied between the peripheral end portion of the flat portion and the metal seal ring to allow a current to flow, and thus, Joule heat is generated by contact resistance of a contact interface to heat.
Implementation Method 2
putting a metal block on the lid, the metal block having a first surface touching a top surface of the lid... the metal block being configured not to interfere the seam welding machine
Data Source
AI summary
A manufacturing method of an optical module including a package and lid, the package having an opening to be sealed with the lid. The manufacturing method includes placing the lid on the package so that the lid covers the opening; putting a metal block on the lid, the metal block having a first surface touching a top surface of the lid; welding the lid to the package using a seam welding machine, the first surface of the metal block touching the top surface of the lid during the welding, the metal block being configured not to interfere the seam welding machine; and detaching the metal block from the lid.