Microphone With Single Back Plate Electrodes
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Solution Overview
Problem
Traditional microphones with a three-layer capacitor structure, comprising two back plates and a diaphragm, have a complex structure and high production costs due to the need for conduction and anti-stuck layers.
Innovation Solution
A microphone design featuring a conducting vibrating diaphragm with through holes, a back plate with opposing electrodes and a support portion, which reduces air damping and improves sensitivity by offsetting force moments, allowing operation under higher bias voltage while maintaining anti-interference characteristics and simplifying the production process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a three-layer capacitor structure with two back plates is used, then the microphone has complete structural coverage, but the structure becomes complicated and production costs increase
Solution Approach 1:
The patent removes one back plate from the traditional two-back-plate structure, retaining only a single back plate with electrode structures. This extraction simplifies the overall structure while maintaining the essential capacitive function for sound detection, directly resolving the contradiction between structural completeness and complexity.
Solution Approach 2:
The patent combines the functions of multiple back plates into a single integrated back plate structure that includes both first and second electrodes. This merging reduces the number of separate components while preserving the necessary electrical and acoustic functions, thereby reducing structural complexity without sacrificing reliability.
2Reliability
If a three-layer capacitor structure with two back plates is used, then the microphone has complete structural coverage, but production costs increase
Solution Approach 1:
By extracting one back plate from the structure, the patent reduces the number of components that need to be manufactured, assembled, and quality-checked. This directly lowers production costs while maintaining sufficient structural coverage through the remaining single back plate with integrated electrode functions.
Solution Approach 2:
The patent merges multiple functional layers into a single back plate structure, reducing the total number of manufacturing steps and assembly operations required. This integration simplifies the production process and reduces costs while preserving the essential structural coverage needed for reliable microphone operation.
3Measurement precision
If higher bias voltage is applied to improve sensitivity, then the microphone sensitivity increases, but air damping effects become more significant
Solution Approach 1:
The patent introduces through-holes at specific locations in the back plate to create localized air flow paths. This local modification reduces air damping in critical regions without compromising the overall structural integrity or requiring changes to the entire back plate design, allowing higher bias voltage to be applied effectively for improved sensitivity.
Solution Approach 2:
The back plate is designed with through-holes creating a porous structure that allows controlled air permeability. This porous design reduces air damping effects by enabling air to pass through rather than creating excessive resistance against the diaphragm motion, thereby allowing higher bias voltage to be used to enhance sensitivity without being limited by air damping.
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 design enhances microphone sensitivity and reduces production costs by simplifying the structure and maintaining interference resistance, even under higher bias voltage conditions.
Implementation Method 1
the middle of the vibrating diaphragm moves relative to the first electrode, i.e. the middle portion of the vibrating diaphragm is near or away from the first electrode, and the edge of the vibrating diaphragm moves relative to the second electrode, thus, the first electrode and the second electrode generate opposite (reversed) electric signals
Data Source
AI summary
A microphone includes a conducting vibrating diaphragm; a back plate opposed to the vibrating diaphragm and including a plurality of through holes; a first electrode formed in a middle of the back plate; a second electrode formed at an edge of the back plate; and a support portion located between the first electrode and the second electrode for supporting the vibrating diaphragm when the vibrating diaphragm is electrified. When the sound pressure is applied in the middle of the vibrating diaphragm and drives the vibrating diaphragm to deform, the middle of the vibrating diaphragm moves relative to the first electrode, and the edge of the vibrating diaphragm moves relative to the second electrode, at this time, the first electrode and the second electrode generate reversed electric signals.