摘要
本論文主要為研究壓電麥克風與揚聲器，其具有體積薄、重量輕、不受磁場干擾等優點。研究之重點在於利用非對稱型壓電雙晶片形式，並採用中心支撐的結構設計，以達到較佳的性能。 壓電麥克風是利用d33圓盤型(disk type)壓電陶瓷元件和黃銅金屬薄膜組成，並採用中心支撐，在收音的狀態下，聲壓由黃銅金屬薄膜收集，而強制壓電陶瓷元件變形，產生訊號輸出；壓電揚聲器則是利用d33圓盤型壓電陶瓷元件和玻璃纖維板(FR4)所組成，同樣採用中心支撐，其發聲原理不僅是由振動板振動空氣發聲，同時加入了介質共振的原理，使壓電揚聲器所產生的機械振動，傳至介質產生共振，以提升壓電揚聲器的低頻聲壓輸出。 經由ANSYS有限元素方法分別模擬分析壓電麥克風與揚聲器在直徑變化下其共振模態頻率的變化，並以不同直徑之壓電麥克風與揚聲器進行實驗。經測試壓電麥克風其靈敏度與頻率響應，驗證壓電麥克風的性能可滿足一般標準功能，而靈敏度與頻率響應曲線以直徑40mm壓電麥克風較佳。另測試壓電揚聲器之頻率響應，以110mm壓電揚聲器在頻率響應曲線較佳。
並列摘要
Piezoelectric microphone and speaker have advantages of thin volume, light weight, and free from magnetic interference is investigated in this thesis. Design of asymmetric piezoelectric bimorph associated with the structure of center support for achieving better performance is the focus. Piezoelectric microphone is constructed with d33 disc type piezoelectric ceramics and brass metal film, and center support structure. Sound pressure is received by the center support structure, and then collected by the brass metal film, which presses the piezoelectric ceramic with deformation. Eventually, output voltage signal is generated corresponding to the deformation. Piezoelectric speaker is composed of d33 disc type piezoelectric ceramic and glass fiber (FR4). While voltage signal is given, piezoelectric ceramic produces radial vibration whose amplitude is amplified by the glass fiber board. By means of the center support, vibration can be transmitted to large objects.ANSYS is used for finite element analysis of both the piezoelectric microphone and speaker. The resonance frequency for various diameters of both the piezoelectric microphone and speaker are determined. In experimental, sensitivity and frequency response are investigated for different diameters. It indicates that the developed microphone diameter preserves good performance. Diameter of 40mm would gain better sensitivity and frequency response. The piezoelectric speaker designed with diameter of 110mm obtains better frequency response.
參考文獻
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