Optical Module Stem Protrusions for Solder Flow Control
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Solution Overview
Problem
The miniaturization of optical modules leads to issues with solder flow outside the connection surface during assembly, causing yield decreases and packaging challenges due to stress applied to the stem and wiring substrate connections.
Innovation Solution
An optical module design featuring a stem with protrusion portions and a wiring substrate with ground conductor patterns and through-holes, allowing for secure electrical connection via brazing or soldering, which prevents solder from flowing outside the connection area and reduces stress on the assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the stem is miniaturized to reduce optical module size, then the optical module achieves miniaturization, but solder flows outside the connection surface causing yield decrease
Solution Approach 1:
The invention introduces protrusion portions on the stem that create localized solder retention areas. By modifying the local geometry at the connection points, solder is confined to specific regions on the connection surface, preventing it from flowing outside while maintaining the miniaturized overall structure.
Solution Approach 2:
The protrusion portions act as intermediary structures between the stem and wiring substrate. These protrusions provide physical barriers that mediate the solder flow, containing it within the connection area while still allowing electrical connection to be established.
2Ease of manufacture
If external force is applied to the wiring substrate during assembly, then stress is applied to the connection between stem and wiring substrate, but solder flow occurs outside the connection surface
Solution Approach 1:
The protrusion portions are designed in advance to accommodate and cushion the solder against external forces during assembly. When stress is applied to the wiring substrate, the protrusions absorb the mechanical stress and prevent solder from being forced outside the connection surface, thereby maintaining manufacturing precision despite assembly challenges.
3Device complexity
If the stem connection surface is flat to simplify structure, then manufacturing is easier, but solder flows outside the outer edge of the connection surface
Solution Approach 1:
Rather than making the entire connection surface complex, the invention applies local geometric modifications in the form of protrusion portions. These localized features provide solder confinement exactly where needed at the connection points, while the rest of the connection surface remains relatively simple and easy to manufacture.
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 effectively suppresses yield decreases and enables miniaturization while maintaining reliable electrical connections, reducing packaging costs and improving manufacturing efficiency.
Implementation Method 1
The two protrusion portions of the stem are electrically connected to the two ground conductor patterns, electrically, by performing brazing or soldering
Implementation Method 2
The two protrusion portions of the stem are electrically connected to the two ground conductor patterns, electrically, by performing brazing or soldering
Data Source
AI summary
Provided are an optical module and a transmission equipment in which a decrease in yield due to brazing or soldering is suppressed. Provided is an optical module including a semiconductor optical element, a stem, and a wiring substrate. The stem includes one or more lead terminals. The wiring substrate includes one or more openings through which the one or more lead terminals, respectively, pass. The stem has a placing surface on which the wiring substrate is placed, and two protrusion portions that are arranged on both external sides, respectively, of the wiring substrate. The wiring substrate further includes a ground conductor layer being positioned on a rear surface and two ground conductor patterns that are arranged on regions, respectively, that are in the vicinity of the two protrusion portions, of a front surface, and are electrically connected to the ground conductor layer.