Optical Waveguide Package Electrodes for Thermal Deformation Control
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Solution Overview
Problem
Existing optical waveguide packages with bonding wires for light-emitting elements face size limitations and thermal expansion issues, leading to deformation and reliability problems due to temperature differences between electrodes.
Innovation Solution
An optical waveguide package design with first electrodes having a lower thermal expansion coefficient than second electrodes, eliminating bonding wires and reducing size by extending electrodes from the light-emitting element mount to the substrate, while maintaining airtight sealing with a lid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bonding wires are used to connect light-emitting elements to electrical wiring, then electrical connection is achieved, but device size increases and thermal expansion issues cause deformation
Solution Approach 1:
The patent removes bonding wires from the system entirely and replaces them with electrodes that are directly integrated into the substrate structure. The electrodes extend from the light-emitting element mounting position through the substrate to the external connection position, eliminating the need for separate bonding wire connections and reducing overall package size.
Solution Approach 2:
The patent combines the electrical connection function with the substrate structure itself. The electrodes are formed as integral parts of the substrate, merging the functions of mechanical support, electrical connection, and thermal management into a single integrated structure, thereby reducing the number of components and package size.
2Reliability
If electrodes with different thermal expansion coefficients are used, then electrical connection is achieved, but temperature differences cause thermal expansion and deformation
Solution Approach 1:
The patent applies different material properties to different regions of the electrode structure. The first electrode portion that contacts the light-emitting element is made of a material with a thermal expansion coefficient matching the element, while the second electrode portion extending through the substrate uses a different material optimized for substrate integration, thereby addressing thermal expansion issues locally in each region.
Solution Approach 2:
The patent employs composite electrode structures where different materials are combined in a single electrode system. The electrode comprises a first portion made of one material and a second portion made of another material, each selected for its thermal expansion properties suitable for its specific location and function, creating a composite structure that manages thermal expansion throughout the device.
3Volume of moving object
If electrodes are extended from element mount to substrate outside, then bonding wires are eliminated and size is reduced, but thermal expansion management becomes critical
Solution Approach 1:
The patent changes the thermal expansion parameter by selecting materials with appropriate thermal expansion coefficients for different electrode portions. The first electrode portion uses a material whose thermal expansion coefficient matches that of the light-emitting element, while the second portion uses a material suitable for substrate integration, thereby managing thermal expansion throughout the extended electrode structure.
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
This design reduces deformation and enhances reliability by minimizing thermal expansion differences, allowing for a smaller package size without compromising performance.
Implementation Method 1
The first electrode has a lower thermal expansion coefficient than the second electrode
Data Source
AI summary
An optical waveguide package includes a substrate including a first surface, a cladding on the first surface and including a second surface facing the first surface, a third surface opposite to the second surface, and an element mount with an opening in the third surface, a core in the cladding, a first electrode located in the element mount, and a second electrode connected to the first electrode and extending to outside the element mount. A light-emitting element is mountable on the first electrode. The first electrode has a lower thermal expansion coefficient than the second electrode.