MEMS麥克風，又稱微機電麥克風。具有高音質、低耗電、耐高溫、抗雜訊等優點，自1980年代以來學者們相繼投入研究，至今已是3G手機的基本配備。有鑑於MEMS麥克風的性能改善多為內部電路晶片製程中的技術改良或新材料的應用，本文使用工業設計上廣泛使用之田口法，對MEMS麥克風外部的封裝腔體尺寸進行設計，並搭配邊界元素聲場分析軟體BEASY，以腔內聲壓最大值的增加做為麥克風性能改善之目標，期望提供一個低成本、較快速設計的新想法。本文以田口法規劃腔體尺寸，搭配BEASY軟體得到建議的尺寸組合，最後進行最佳化，得到最佳的尺寸設計。結果顯示，正常發聲頻帶下田口法得到參數尺寸組合已使腔內聲壓有2.2 dB ~ 2.4dB之增益，且僅空孔位置此參數影響最為顯著，只要移動空孔位置即可達到最佳化設計；而最佳化結果顯示將空孔位置往邊界移動，確實可得到更大的聲壓值，約有0.3 dB ~ 0.6 dB之聲壓增益；從聲場分布圖可看出，聲源頻率增加亦會使角落最大聲壓值更大且沿腔體厚度上呈現均勻分布。

Since the micro-electro mechanical system microphone, MEMS microphone, has the advantages of superior sound quality, low power consumption, higher temperature resistance and anti-noise ability in used. The researchers therefore have studied the functions of MEMS microphone since 1980s. The MEMS microphones is applied as the part of 3G mobile phone in the market. Though the functions of microphone are improved by manufacturing process technique and new material designed, this study tends to provide a new, low-cost and rapid design idea to gain the performance in chamber of microphone. Taguchi method and BEASY software, which is boundary element method, are combined to evaluate the results of the design in sound field. Taguchi method is a famous method in industrial design to find out relations between system parameters and chamber size. BEASY is a tool for sound field analysis in the research. The result from Taguchi method appears the sound pressure level gain about 2.2 dB to 2.4 dB due to the change of microphone chamber size only. It is also interested in studying the optimization design for position of microphone. It is displayed that the location of port is closer to the boundary of chip will also increase about 0.3 dB to 0.6dB sound pressure level in sound field. The higher frequency of sound source will also create larger sound pressure level at two corners on the port.

目錄…………………………………………………………i
表目錄………………………………………………………iv
圖目錄………………………………………………………vi
中文摘要……………………………………………………ix
Abstract ……………………………………………………x
第一章 緒論
1.1 研究動機與目的………………………………………1
1.2 文獻回顧與MEMS麥克風簡介 ………………………2
第二章 研究基本理論
2.1 聲學相關理論…………………………………………9
2.1.1 波動方程式 …………………………………………9
2.1.2 聲波的反射、透射與散射…………………………10
2.2 邊界元素法……………………………………………11
2.2.1 邊界元素法原理……………………………………11
2.2.2 以邊界元素法模擬聲場變化………………………12
2.2.3 邊界元素軟體介紹與處理步驟……………………14
2.2.4 使用元素介紹………………………………………16
2.2.5 模擬參數設定………………………………………18
第三章 參數設計法
3.1 參數設計法……………………………………………25
3.2 田口法概述……………………………………………25
3.2.1 品質特性SN比與損失函數 ………………………27
3.2.2 參數選擇與直交表設計……………………………29
3.2.3 變異數分析…………………………………………30
3.2.4 各因子效應與交互作用……………………………31
3.2.5 確認結果之實驗……………………………………34
3.3 最佳化設計……………………………………………35
第四章 模擬與結果討論
4.1 結果與討論 …………………………………………43
4.1.1 田口法………………………………………………43
4.1.2 最佳化設計…………………………………………46
4.1.3 聲場分布……………………………………………46
4.2 聲壓增益 ……………………………………………47
4.2.1 聲壓增益與頻率效應………………………………47
4.2.2 聲壓增益與溫度效應………………………………48
第五章 結論與建議
5.1 結論……………………………………………………65
5.2 建議……………………………………………………66
參考文獻 …………………………………………………68

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