Capacitor Microphone Crimp Segmentation for Noise Shielding
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Solution Overview
Problem
Existing capacitor microphone units face challenges in effectively blocking high frequency noise due to dispersed pressure contact between the crimp and the ground wiring pattern, leading to incomplete shielding and difficulty in verifying or measuring the contact.
Innovation Solution
A capacitor microphone unit design where the open end of the cylindrical case is folded inward to form a crimp that presses a perforated ground wiring pattern on the circuit board at multiple equally spaced positions, ensuring conductive contact and enhanced shielding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the crimp presses the ground wiring pattern at a single flat surface, then the manufacturing process is simple, but the pressure contact is dispersed and shielding effectiveness deteriorates
Solution Approach 1:
The ground wiring pattern is segmented into multiple contact regions along the peripheral edge of the circuit board. The crimp presses these segmented regions at multiple equally spaced positions, transforming a single dispersed contact into multiple concentrated contacts. This segmentation resolves the contradiction by maintaining simple crimp structure while improving shielding effectiveness through distributed pressure points.
Solution Approach 2:
The ground wiring pattern is designed with locally enhanced conductive regions along the peripheral edge. These local quality improvements ensure that when the crimp applies pressure at multiple positions, each contact point achieves sufficient electrical connection for effective shielding. This allows the simple crimp structure to achieve reliable shielding through strategically designed local contact zones.
2Ease of manufacture
If the ground wiring pattern is flat, then the manufacturing process is simple, but the contact between crimp and wiring pattern becomes partial or point contact making verification difficult
Solution Approach 1:
The ground wiring pattern is segmented into multiple discrete contact regions along the peripheral edge. This segmentation creates distinct, measurable contact zones that are easier to verify than a continuous flat surface. Each segmented region can be independently inspected for proper contact, resolving the verification difficulty while maintaining manufacturing simplicity.
Solution Approach 2:
Instead of requiring complete surface contact, the design uses multiple partial contact points along the peripheral edge. This partial action approach is sufficient for achieving effective shielding and makes verification more practical, as only these specific partial contact regions need to be verified rather than an entire surface.
3Device complexity
If the crimp contacts the ground wiring pattern at minimal points, then the structure is simple, but high frequency signals are not sufficiently blocked
Solution Approach 1:
The contact structure is segmented into multiple equally spaced positions along the peripheral edge. This segmentation transforms a single minimal contact point into multiple distributed contact points, effectively blocking high frequency noise through increased contact density while maintaining overall structural simplicity.
Solution Approach 2:
The contact arrangement transitions from a single-point contact in one location to a distributed array of contact points along the peripheral dimension. This dimensional expansion along the board edge increases shielding effectiveness against high frequency noise without significantly increasing structural complexity.
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 design reliably blocks electromagnetic waves and noise, preventing their interference with audio signals by ensuring consistent and effective electrical connection between the crimp and the ground wiring pattern.
Implementation Method 1
The crimp 14 electrically connects an evaporated surface of the diaphragm 20, the ring 26 and the case 10 to a ground wiring pattern of the printed circuit board 30
Implementation Method 2
The crimp 14 of the case 10 is brought into pressure contact with the ground wiring pattern of the circuit board 30 in order to accomplish an electric connection, and protects the microphone unit against noise caused by high frequency signals
Implementation Method 3
The diaphragm 20 and the fixed electrode 22 are formed as a capacitor. A capacitance of the capacitor varies with vibrations, so that electric charges are discharged or introduced
Implementation Method 4
The capacitor microphone shown in FIG. 1 is of an electret type, in which electric charges are semi-permanently held on the diaphragm 20
Data Source
AI summary
A capacitor microphone unit comprises a diaphragm vibrated in response to voices, a fixed electrode facing the diaphragm, an insulator, a circuit board, and a cylindrical unit case housing the foregoing components. An open end of the cylindrical unit case is folded inward, and holds a peripheral edge of the circuit board, the folded part functioning as a crimp; a ground wiring pattern is present on the peripheral edge of the circuit board, and is perforated at a plurality of positions along the peripheral edge of the circuit board; and the circuit board is pressed by the crimp at a plurality of positions.