微型揚聲器之特性分析與實驗驗證

Analysis and Experiment Verification of a Micro-speaker

王怡婷(Yi-Ting Wang)

指導教授 ： 趙昌博

中原大學/工學院/機械工程研究所/碩士(2005年)

https://doi.org/10.6840/cycu200500659

摘要

本文提出動圈式微型揚聲器( Moving-coil Type Micro-speaker )於電磁、機械及聲學耦合情況下之分析，以及其頻率響應之實驗驗證。微型揚聲器之作動主要藉由電壓輸入黏附於振膜( Diaphragm )下方之音圈馬達( Voice Coil Motor, VCM )後，音圈馬達與磁場作用所產生之勞倫茲力推動音圈馬達，使其上方之振膜振動以發出聲音，其中振膜在本研究中具有皺褶(Corrugation )之形貌。本研究為了探討振膜皺褶對頻率響應之影響，採用了有限元素( Finite Elements )得出其模態，並結合模態分析以及有限元素分析之磁場分布而取得振膜之動態響應。爾後將聲學效應納入考慮，則微型揚聲器之頻率響應即可得出。本文所得出模擬結果與實驗相互驗證，可知其於中低頻區段可與實驗達到一致。

關鍵字

動圈式微型揚聲器 ； 皺褶 ； 振膜 ； 有限元素 ； 音圈馬達

並列摘要

In this study, a moving-coil type micro-speaker is investigated for the demands on high sound quality for commercial cell phones. To put emphasis on high frequency responses of the micro-speaker, one of commonly-seen means is adoption of corrugation on the diaphragm. To confirm the effectiveness of the corrugation, the diaphragm model is constructed by finite elements to extract the dynamic modes. These modes are then combined with the magneto-electrical model of voice coil motor (VCM) that is attached to the bottom side of the diaphragm. The modeling of VCM is carried out through finite elements on the magnetic field around VCM. To complete modeling, the acoustic effects of the air are also modeled. Assembling all derived system equations and solving them, the frequency response of the micro-speaker can be obtained. Results of the theoretical analysis are confirmed by experiments.

並列關鍵字

corrugation ； voice coil motor ； diaphragm ； finite elements ； moving-coil type micro-speaker

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