CAN Package Stem Slot for Optical Module Impedance Matching
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Solution Overview
Problem
Existing optical modules face reliability issues due to weak connections between CAN packages and flexible boards, which are susceptible to temperature, humidity, and mechanical stress, and suffer from impedance mismatch and parallel plate resonance, affecting high-frequency transmission characteristics.
Innovation Solution
An optical module design featuring a CAN package with a stem having a slot for the board's insertion, where the stem also acts as a ground conductor, eliminating the need for stubs and ensuring parallel contact, thus enhancing connection strength and impedance matching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If lead pins are inserted into through-holes of the flexible board, then connection strength is improved, but impedance mismatch occurs due to remaining stub portions
Solution Approach 1:
The patent applies preliminary action by pre-configuring the lead pin length to exactly match the through-hole depth during manufacturing, eliminating the need for post-insertion cutting. This prevents stub formation before the connection is even made, resolving the impedance mismatch issue while maintaining strong mechanical connection through the through-hole insertion method.
2Reliability
If the stem and ground conductor are connected without gap, then parallel plate resonance is prevented, but manufacturing precision is required
Solution Approach 1:
The patent merges the stem structure with the ground conductor function by configuring the stem to directly contact and electrically connect with the ground conductor on the flexible board. This integration eliminates the air gap between stem and ground conductor, preventing parallel plate resonance in the high-frequency band while the ground conductor pattern on the board provides the necessary precision.
3Ease of operation
If lead pins have extra length for easy connection, then ease of operation is improved, but stub formation degrades high-frequency characteristics
Solution Approach 1:
The patent applies parameter changes by precisely controlling the lead pin length parameter to match the through-hole depth, eliminating the extra length that causes stubs. This parameter optimization allows the lead pins to be inserted easily into the through-holes while completely avoiding the formation of residual stub portions that would degrade high-frequency characteristics.
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 solution provides high reliability and improved high-frequency transmission characteristics by preventing impedance mismatch and parallel plate resonance, making the optical module more resilient to environmental and mechanical stress.
Implementation Method 1
parallel plate resonance occurs in a frequency band that depends on the gap therebetween
Implementation Method 2
the lead pin being protruded from the surface... the electrode is electrically connected to the lead pin
Data Source
AI summary
There are included a CAN package (2) having a stem (22) and lead pins (23a and 23b) protruding from the stem (22), and a board (3) having pads (33a and 33b) for connecting lead pin. The CAN package (2) has a slot (222) provided in a surface of the stem (22) from which the lead pins (23a and 23b) protrude. One end of the board (3) is inserted into the slot (222), and the pads (33a and 33b) for connecting lead pin are electrically connected to the lead pins (23a and 23b).