Capacitor Microphone Counterelectrode Using Printed Circuit Board
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Solution Overview
Problem
The production of high-quality counterelectrodes for capacitor microphones is complex and costly, while simpler stamped counterelectrodes result in reduced microphone quality due to non-flat surfaces and increased spacing between the diaphragm and counterelectrode, leading to decreased sensitivity and signal-noise ratio.
Innovation Solution
A capacitor microphone design utilizing a printed circuit board with an insulating carrier and electrically conductive surfaces as a single structural unit for the counterelectrode, allowing for automated, cost-effective production and improved flatness, with the option to mount an impedance converter on the counterelectrode or a flexible circuit board to minimize thermal stress and wiring complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If stamped counterelectrodes are used, then production cost is reduced, but manufacturing precision deteriorates due to non-flat surfaces
Solution Approach 1:
The patent changes the manufacturing method parameter from traditional stamping to printed circuit board technology. PCB manufacturing processes inherently produce flat surfaces with high precision, thus improving manufacturing precision while maintaining cost-effectiveness through automated production
Solution Approach 2:
The patent replaces the mechanical stamping process with a printed circuit board manufacturing process. The PCB manufacturing system uses photolithography and automated lamination processes that inherently produce flat, precise surfaces without requiring complex mechanical pressing and finishing operations
2Ease of manufacture
If greater spacing between diaphragm and counterelectrode is used, then ease of manufacture is improved, but sensitivity deteriorates
Solution Approach 1:
The patent changes the spacing parameter to an optimized value that balances manufacturing ease with sensitivity. The PCB structure allows for precise control of the spacing distance, enabling manufacturers to achieve optimal values that maintain high sensitivity while facilitating easier assembly compared to traditional tight-tolerance mechanical structures
3Manufacturing precision
If traditional turning process is used for counterelectrode, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent merges the counterelectrode structure with the electronic circuit board into a single integrated PCB unit. This combination eliminates the need for separate turning, insulation injection, and lapping processes, reducing device complexity while maintaining manufacturing precision through the inherent capabilities of PCB technology
Solution Approach 2:
The printed circuit board serves multiple functions simultaneously: it provides the conductive counterelectrode surface, the insulating support structure, the mounting platform for electronic components, and the electrical connection pathways. This multi-functionality eliminates the need for separate components and assembly steps
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 enables the production of high-quality, cost-effective capacitor microphones with improved sensitivity and reduced moisture and solids-transmitted sound sensitivity, allowing for easier preliminary testing and flexible frequency response adjustments.
Implementation Method 1
The capacitance C of the capacitor is dependent on the plate area A and the spacing d of the capacitor plates. Due to a sound acting thereon the diaphragm oscillates in front of the counterelectrode, resulting in a change in the spacing d of the two capacitor plates and thus a change in the capacitance C of the capacitor.
Data Source
AI summary
There is provided a capacitor microphone comprising a microphone capsule (100), which has an at least partially electrically conductive diaphragm (110) and a counterelectrode (120) associated therewith. The counterelectrode (120) has a printed circuit board (21) having a carrier of an insulating material (121a) and at least one electrically conductive surface (121b).