Microphone With Side-Surface Sound Holes and Integrated Substrate
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Solution Overview
Problem
Conventional microphone designs face challenges in reducing size and achieving high sensitivity due to structural restrictions, such as the need for gaps for acoustic characteristics and the co-location of sound holes and electrical connections, which complicates assembly and increases costs.
Innovation Solution
A compact microphone design featuring a tubular case with side-surface sound holes and a substrate with an electrode portion, allowing for reduced size and enhanced sensitivity without the need for internal gaps or sound holes on the substrate, and enabling directivity through strategically placed sound holes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sound holes are provided in the substrate with electrical connection portions, then acoustic characteristics can be achieved, but air leakage occurs at the electrical connection portion and structural restrictions increase
Solution Approach 1:
The sound hole formation is segmented from the substrate and relocated to the case body. The case is divided into distinct functional zones: sound collection portion with sound holes, accommodation portion for the microphone, and sealing portion. This segmentation allows sound holes to be formed in the case rather than the substrate, eliminating the conflict between sound holes and electrical connections.
Solution Approach 2:
The sound hole function is extracted from the substrate and transferred to the case. The substrate's role is simplified to only electrical connection and support, while the case assumes the acoustic function through integrated sound holes. This extraction resolves the air leakage problem at electrical connection portions by removing sound holes from the substrate entirely.
2Reliability
If a gap is provided between the microphone case and microphone unit, then acoustic characteristics can be formed, but the size of the microphone cannot be reduced
Solution Approach 1:
The acoustic cavity and case structure are merged into a single integrated component. The case simultaneously serves as the housing structure and the acoustic resonator, with the accommodation portion forming the acoustic cavity. This eliminates the need for a separate gap between case and microphone unit, as the acoustic characteristic is formed within the integrated case structure itself.
Solution Approach 2:
The case is designed with multi-functionality, serving simultaneously as: (1) the protective housing, (2) the acoustic resonator with sound holes, and (3) the mounting structure for the microphone. This multi-functionality consolidates multiple components into one, eliminating the need for additional gaps and reducing overall microphone size.
3Ease of manufacture
If sound holes and electrical connection portion are on the same plane, then assembly is simplified, but air leakage occurs and acoustic performance deteriorates
Solution Approach 1:
The sound holes and electrical connection portions are separated in the vertical dimension (depth direction). Sound holes are formed in the case's outer surface while electrical connection portions are on the substrate's inner surface, separated by the case thickness. This dimensional separation eliminates air leakage paths while maintaining assembly simplicity through the integrated case design.
Data Source
AI summary
A microphone includes a tubular case having a bottom surface, a side surface and an opened top, a substrate which is fixed so as to block an opening portion of the opened top of the case, and has an electrode portion on an upper surface thereof, and a side-surface sound hole formed in the side surface of the case.