Conductive Foam EMI Shield for Optical Transceivers
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Solution Overview
Problem
Conventional EMI shielding solutions for optical transceivers, such as gaskets and collars, fail to provide adequate shielding against high-frequency electromagnetic interference (EMI) due to gaps and leakage issues, particularly in the TOSA/ROSA areas, which are critical for data transmission and reception.
Innovation Solution
The use of electrically-conductive foam wrapped around the perimeter of EMI shields, which eliminates gaps and provides effective sealing and electrical grounding, ensuring that the shields can operate up to 60 GHz or more without significant EMI leakage, by compressing and rebounding to maintain contact and seal gaps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional EMI shielding solutions (gaskets and collars) are used, then the shielding structure is simple, but gaps and leakage issues occur particularly in TOSA/ROSA areas, reducing shielding effectiveness
Solution Approach 1:
The patent employs a flexible EMI shield made of conductive foam material that can deform to conform to the housing contours. This flexibility allows the shield to maintain continuous electrical contact and seal gaps around TOSA/ROSA areas without requiring complex rigid structures, thereby improving shielding effectiveness while keeping the design relatively simple.
Solution Approach 2:
The patent uses conductive foam material with a porous structure that provides both mechanical compliance and electrical conductivity. The porous nature of the foam allows it to compress and rebound to maintain contact with the housing, eliminating gaps and improving EMI shielding effectiveness in critical areas like TOSA/ROSA interfaces.
2Object-affected harmful factors
If rigid EMI shields are used, then the shielding structure is stable, but gaps form at corners and interfaces, allowing EMI leakage
Solution Approach 1:
The patent transitions from rigid static shields to a dynamic flexible shield that can adapt its shape. The conductive foam material compresses under pressure to fill gaps at corners and interfaces, then rebounds to maintain continuous contact. This dynamic behavior eliminates EMI leakage paths while preserving structural stability through the foam's elastic properties.
Solution Approach 2:
The patent changes the physical state of the shield material from rigid to flexible by using conductive foam. This parameter change allows the shield to modify its geometry and contact pressure to eliminate gaps at critical interfaces, thereby preventing EMI leakage without compromising the overall structural stability of the shielding system.
3Ease of manufacture
If gaps are left in the shield structure for assembly, then the ease of manufacture is improved, but EMI shielding effectiveness is reduced due to leakage paths
Solution Approach 1:
The flexible conductive foam shield can be easily installed by simply placing it in the housing without requiring precise alignment or complex assembly procedures. The material's flexibility allows it to self-conform to the housing contours and fill gaps automatically, maintaining EMI shielding effectiveness while significantly simplifying the manufacturing and assembly process.
Solution Approach 2:
The conductive foam shield performs self-alignment and self-sealing functions through its elastic deformation. When installed, the foam automatically conforms to the housing shape and maintains continuous electrical contact without requiring external adjustment or complex assembly fixtures, thereby simplifying manufacturing while ensuring reliable EMI shielding.
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 electrically-conductive foam effectively seals gaps and maintains electrical grounding, significantly reducing EMI leakage and enhancing the shielding effectiveness of EMI shields for optical transceivers, particularly in high-frequency ranges, thereby ensuring reliable data transmission and reception.
Implementation Method 1
The electrically-conductive foam may be configured to be compressible and resilient such that the electrically-conductive foam helps the EMI shield establish, maintain, and improve good electrical grounding contact between the EMI shield and the housing
Implementation Method 2
The EMI shield includes sidewalls depending downwardly from the portion that includes the openings... Electrically-conductive resiliently compressible porous material is disposed around an outer perimeter defined by the sidewalls
Data Source
AI summary
Exemplary embodiments are disclosed of EMI shields including electrically-conductive foam (broadly, electrically-conductive resiliently compressible porous material). An exemplary embodiment includes an electromagnetic interference (EMI) shield for an optical transceiver including transmitter and receiver optical sub-assemblies. The EMI shield includes a portion having openings configured for receiving the transmitter and receiver optical sub-assemblies therethrough to thereby allow the EMI shield to be fit over the transmitter and receiver optical sub-assemblies for installation along a portion of the optical transceiver. The EMI shield also includes sidewalls depending from the portion that includes the openings. Electrically-conductive resiliently compressible porous material (e.g., electrically-conductive foam, etc.) is along at least a portion of an outer perimeter defined by the sidewalls.