Optical Transceiver FPC Board Hairpin Bend Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional optical modules with co-axial shells face impedance issues and signal degradation when a support member is present, and lead terminal breakage when it is absent, due to increased operational speeds exceeding 10 GHz in optical communication systems.
Innovation Solution
A flexible printed circuit (FPC) board design without a support member, featuring a hairpin bend and strategically placed ground patterns and via holes to manage stress and maintain signal integrity, allowing the FPC board to bend without affecting lead terminals, thus eliminating the need for a support member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a support member is attached to the stem to cover it fully, then lead terminal breakage is prevented, but signal shape degradation occurs due to impedance upset
Solution Approach 1:
The invention extracts and removes the support member from the optical module structure. By eliminating the support member that causes impedance upset, the patent achieves both lead terminal protection through alternative means (bent FPC board design) and maintains signal integrity without degradation.
Solution Approach 2:
The invention changes the physical state and configuration parameters of the FPC board, specifically bending it to form a hairpin shape with the bent portion positioned at the stem end. This parameter change allows the FPC board to provide mechanical support and stress absorption without requiring an additional support member, thus preventing lead terminal breakage while maintaining proper impedance characteristics.
2Device complexity
If the FPC board is bent adjacent to the lead terminals, then stress is absorbed, but lead terminal breakage occurs due to stress concentration
Solution Approach 1:
The invention positions the bent portion of the FPC board in a specific spatial dimension - at the end of the stem rather than adjacent to the lead terminals. This dimensional repositioning allows stress absorption through the bent portion while preventing stress concentration at the lead terminal roots, thereby maintaining lead terminal strength without requiring additional support structures.
Solution Approach 2:
The bent portion of the FPC board acts as an intermediary element that absorbs and distributes mechanical stress away from the lead terminals. By positioning the bent portion at the stem end, it serves as a stress mediator that protects the lead terminals from breakage while maintaining electrical connectivity and signal integrity.
3Ease of operation
If the FPC board is bent to connect optical module with circuit board, then flexibility is achieved, but signal transmission quality degrades due to impedance changes
Solution Approach 1:
The invention applies local quality by creating a specific bent portion with defined geometric characteristics at the stem end of the FPC board. This localized bending structure is designed with specific radius and angle parameters that maintain impedance control while providing the necessary flexibility for connection between the optical module and circuit board.
Data Source
AI summary
An optical transceiver that provides an optical module, a circuit board, and a housing, where the housing encloses the optical module and the circuit board therein. The optical module provides lead terminals connected with circuits on the circuit board through a flexible printed circuit (FPC) board. The FPC board is bent at a bent portion corresponding to an end of the optical module as the top surface thereof becomes inner. The bent portion of the FPC board provides a bared portion in the back surface thereof, where the bared portion removes a ground pattern.