Opto-electronic Assembly Self-Alignment Flexible PCB
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Solution Overview
Problem
High-speed optical communication systems face challenges in minimizing manufacturing costs and maximizing performance due to the use of metal cans in Receive Optical Sub-Assemblies (ROSAs), which hinder bandwidth and increase assembly costs, while also requiring mechanical support and alignment for photodiodes and lenses on flexible PCBs.
Innovation Solution
Mounting photodiodes and amplifiers directly on flexible PCBs with a cover and lens assembly that provides mechanical stiffness and self-alignment, using areas of different materials to secure the cover and lens, ensuring optimal alignment and reducing signal path impedance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If photodiode and amplifier are mounted in a metal can with wire leads and flexible PCB, then mechanical support and electrical connections are provided, but manufacturing cost increases and operating bandwidth is limited
Solution Approach 1:
The patent removes the metal can enclosure and intermediate wire leads/header posts from the conventional ROSA structure. The photodiode and amplifier are mounted directly on the flexible PCB, eliminating unnecessary components and reducing signal path length. This extraction of non-essential elements reduces both manufacturing cost and device complexity while maintaining mechanical support and electrical connections through the PCB substrate itself.
Solution Approach 2:
The patent merges the functions of mechanical support, electrical connection, and signal transmission into the flexible PCB structure. The PCB serves simultaneously as the mounting substrate, the electrical interconnect medium, and the structural support framework, eliminating the need for separate metal cans and wire leads. This consolidation reduces assembly complexity and cost while improving high-frequency performance.
2Device complexity
If photodiode and amplifier are mounted directly on flexible PCB, then manufacturing cost is reduced and bandwidth is improved, but mechanical support and alignment capability are insufficient
Solution Approach 1:
The patent incorporates alignment features and mechanical support structures directly into the PCB fabrication process before component mounting. The rigid support structures and alignment marks are pre-formed during PCB manufacturing, ensuring proper component placement and stable mechanical support before the photodiode and amplifier are attached. This preliminary preparation eliminates the need for post-assembly alignment adjustments and ensures reliable mechanical support.
Solution Approach 2:
The patent enhances specific regions of the flexible PCB with rigid support structures and differentiated material properties where components are mounted. The PCB exhibits local variations in rigidity, thermal properties, and electrical characteristics tailored to the specific needs of the photodiode and amplifier mounting areas. This localized enhancement provides necessary mechanical support and alignment stability without compromising the overall flexibility and cost-effectiveness of the structure.
3Reliability
If cover and lens assembly is attached to PCB, then mechanical rigidity and alignment are provided, but attachment method must be low cost and compatible with conventional PCB processes
Solution Approach 1:
The patent designs the cover and lens assembly with self-aligning features that automatically position components correctly during attachment to the PCB. The assembly includes integrated alignment marks,定位 holes, or geometric features that guide proper placement without requiring complex external alignment equipment or multi-step adjustment processes. This self-service capability ensures accurate alignment and mechanical rigidity while maintaining compatibility with conventional, cost-effective PCB manufacturing processes.
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 approach reduces manufacturing costs, enhances high-frequency performance, and ensures reliable mechanical support and alignment, minimizing the risk of misalignment or breakage, while maintaining compatibility with conventional PCB manufacturing processes.
Implementation Method 1
said cover having an optically transparent aperture containing a lens configured to focus modulated light signals from a fibre onto said photodiode
Data Source
AI summary
A construction and configuration for the receiving function of a high speed optical communication system with reduced manufacturing cost and improved performance. In an aspect, mounting the cover and lens provides a self-alignment behaviour that advantageously positions the cover and the lens to be in the optimum position for the photodiode. An assembly of electronic components receives data using an optical fibre. In one aspect, the assembly includes a photodiode, an amplifier coupled to the photodiode, and a printed circuit board on which the photodiode and amplifier are physically mounted, The printed circuit board has areas of a first material to which components may be attached using a fixing agent, and areas of a second material to which components will not attach using the fixing agent. Conductive bond wires are configured to directly couple the amplifier and the photodiode to conductive traces on an opposite side of the printed circuit board. A cover is configured to cover the amplifier and the photodiode, and is physically attached to the printed circuit board to provide mechanical rigidity around the photodiode and the amplifier. The cover has an optically transparent aperture containing a lens configured to focus modulated light signals from a fibre onto the photodiode. The printed circuit board has areas of a first material and second material configured to fix a location of the cover by use of the fixing agent to align the lens to focus the light signals from the fibre onto the photodiode.