Feedthrough Capacitor Spring Finger Coupling
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Solution Overview
Problem
Ceramic-based feedthrough capacitors are fragile and have limited capacitance, making them susceptible to damage and size restrictions, while polymer-based capacitors are sensitive to temperature and limited in smaller applications.
Innovation Solution
A feedthrough device with a grounded outer electrode, an inner electrode, and a dielectric material, featuring a capacitor assembly with spring fingers for conductive coupling and a diamond-like patterned interior wall for increased surface area, using monolithic multilayer ceramic capacitors for high capacitance and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ceramic-based feedthrough capacitors are used, then capacitance is provided, but the capacitor becomes fragile and susceptible to cracking from physical forces and temperature changes
Solution Approach 1:
The patent uses a composite construction combining a flexible polymer dielectric material with metal layers (aluminum foil) to create a feedthrough capacitor that is both durable and capable of withstanding physical forces and temperature changes, eliminating the fragility of pure ceramic designs
Solution Approach 2:
The patent employs a flexible polymer dielectric film instead of rigid ceramic, allowing the capacitor to be more resilient to mechanical stress and thermal expansion, while still providing the necessary electrical insulation and capacitance functionality
2Reliability
If ceramic-based feedthrough capacitors are used, then capacitance is provided, but the capacitor has limited capacitance per unit volume
Solution Approach 1:
The patent transitions from the rigid three-dimensional ceramic structure to a flexible film-based construction that can be wound or folded, effectively utilizing spatial arrangement in new dimensions to achieve higher capacitance per unit volume
Solution Approach 2:
The flexible polymer dielectric film allows for more efficient packing and higher surface area utilization compared to rigid ceramic, enabling increased capacitance density without proportionally increasing the overall volume
3Strength
If polymer-based feedthrough capacitors are used, then durability is improved, but the capacitor becomes sensitive to temperature changes
Solution Approach 1:
The patent combines polymer dielectric material with metal layers and potentially ceramic components to create a composite structure that leverages the mechanical flexibility of polymers while mitigating their temperature sensitivity through the stabilizing properties of other materials
4Reliability
If larger form factor capacitors are constructed, then capacitance increases, but the diameter of the capacitor through hole and center electrode must be increased
Solution Approach 1:
The flexible film construction allows capacitance to be increased by utilizing the third dimension (thickness of stacked or wound layers) rather than simply increasing the through-hole diameter, enabling higher capacitance while maintaining compact through-hole dimensions
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 a durable feedthrough capacitor with high capacitance, resistance to physical forces and temperature changes, and flexibility in size, offering improved reliability and filtering accuracy.
Implementation Method 1
A feedthrough capacitor is a limited inductance conductor with a known threshold of capacitance
Implementation Method 2
a first array of spring fingers conductively coupled to the first terminal of each of the one or more capacitors
Data Source
AI summary
A feedthrough capacitor includes an inner electrode that extends coaxially within a grounded outer electrode. A non-conductive, epoxy-based potting material insulates and adhesively joins opposing roughened portions of the inner and outer electrodes. A capacitor assembly extends between the inner and outer electrode and serves to bypass relatively high frequency signals carried by the inner electrode to the grounded outer electrode. The capacitor assembly includes a plurality of monolithic multilayer ceramic capacitors, each capacitor having first and second terminals that are respectively surface mounted onto inner and outer concentric conductive rings. A plurality of deflectable tines project radially inward from the inner ring and resiliently circumferentially contact the exterior of the inner electrode. Similarly, a plurality of deflectable tines project radially outward from the outer ring and resiliently circumferentially contact the interior of the outer electrode.