Capacitive Transducer Diaphragm Segmentation for Sensitivity and Short Circuit Prevention
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Solution Overview
Problem
Capacitive-type electro-acoustic transducers face challenges in achieving a wide dynamic range and miniaturization due to limited frequency bandwidth and the risk of diaphragm contact with the fixed electrode, leading to short circuits when attempting to increase sensitivity.
Innovation Solution
A capacitive-type electro-acoustic transducer design incorporating a resonance circuit that adjusts signal frequencies, a fixed electrode, a vibrating diaphragm, and a contact part that presses the diaphragm against the fixed electrode, increasing capacitance and reducing the distance between them to enhance sensitivity and prevent short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the distance between the diaphragm and the fixed electrode is reduced to increase sensitivity, then sensitivity is improved, but the diaphragm contacts the fixed electrode causing a short circuit
Solution Approach 1:
The patent divides the diaphragm into multiple independent vibration units (first diaphragm, second diaphragm, etc.) with different vibration characteristics. This segmentation allows each unit to vibrate independently with controlled amplitude, preventing any single diaphragm from contacting the fixed electrode while maintaining high sensitivity through the combined effect of multiple diaphragms at reduced distances.
Solution Approach 2:
Different diaphragms are designed with different properties (mass, tension, dimensions) to create local variations in vibration characteristics. The first diaphragm has different vibration characteristics than the second diaphragm, allowing optimized local responses that collectively achieve high sensitivity without short circuiting.
2Device complexity
If a single diaphragm is used to achieve simple structure, then device complexity is reduced, but frequency bandwidth is limited
Solution Approach 1:
The patent uses multiple diaphragms with different vibration characteristics (different masses, tensions, or dimensions) to cover different frequency ranges. Each diaphragm responds optimally to specific frequency bands, and their combined output achieves wide frequency bandwidth coverage while maintaining a relatively simple overall structure.
Solution Approach 2:
Multiple diaphragms serve different functional purposes within the same transducer structure. Each diaphragm is optimized for specific frequency ranges, and together they provide universal coverage across the entire audio spectrum, making the transducer adaptable to wide frequency requirements.
3Adaptability or versatility
If multiple units are combined to achieve wide dynamic range, then frequency bandwidth is improved, but the number of components increases making miniaturization difficult
Solution Approach 1:
Multiple diaphragms are integrated into a single compact transducer structure where they share common components (fixed electrode, housing, electrical connections). This merging approach achieves wide dynamic range through multiple vibration units while minimizing the total number of discrete components and enabling miniaturization.
Solution Approach 2:
The patent arranges multiple diaphragms in a nested or overlapping configuration where they share space efficiently. The diaphragms are positioned and dimensioned to maximize space utilization, allowing wide dynamic range coverage within a compact form factor suitable for miniaturization.
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 achieves a wider dynamic range and miniaturization by increasing sensitivity and reducing the need for large amplifiers, allowing for smaller transformers and amplifiers, making the transducer suitable for outdoor use with an electret-based bias voltage.
Implementation Method 1
a resonance circuit that outputs an adjusted signal obtained by making a signal component of a predetermined frequency contained in an electric signal outputted from a sound source device larger than a signal component of another frequency
Implementation Method 2
a diaphragm that is provided facing the fixed electrode and that vibrates according to a potential difference generated between the diaphragm and the fixed electrode on the basis of the adjusted signal
Implementation Method 3
a contact part that contacts a partial region of the diaphragm and presses the partial region against the fixed electrode
Data Source
AI summary
An earphone includes a resonance circuit that outputs an adjusted signal obtained by making a signal component of a predetermined frequency contained in an electric signal outputted from a sound source device larger than a signal component of another frequency, a fixed electrode that is fixed to a housing, a diaphragm that is provided facing the fixed electrode and that vibrates according to a potential difference generated between the diaphragm and the fixed electrode on the basis of the adjusted signal, a contact part that contacts a partial region of the diaphragm and presses the partial region against the fixed electrode, and a sound emitting part that emits sound generated by vibration of the diaphragm to the outside of the housing.