生物纖維振膜之圓形揚聲器最佳化設計與研製

Optimal Design and Manufacturing of Circular Flat-Panel Speakers Using Biocellulose Membrane

本文主要為生物纖維薄膜運用於平面揚聲器振膜之特性探討及生物纖維薄膜製造平面揚聲器振膜，以探討不同製程參數之生物纖維薄膜運用在揚聲器振膜上的效果。本研究針對兩種不同尺寸大小設計與製造平面揚聲器，其規格為小型圓形（ψ16mm╳H7.8mm）及矩形（L162mm╳W115mm╳H10mm）等兩種。針對生物纖維薄膜作為揚聲器振膜之可行性、作改質、不同烘乾溫度與厚度等製程參數進行材質的探討，藉由拉伸試驗，取得其機械性質（楊氏係數、卜易淞比），並討論不同生物纖維薄膜作為揚聲器振膜應用於平面揚聲器的聲壓曲線的差異性，找出製造生物纖維振膜之最佳製造參數。在分析方面，運用有限元素套裝軟體ANSYS建立模型，計算振動板上振幅與相位角，並代入聲壓公式運算，其運算解代入Fortran軟體求解模擬之聲壓位準值。將製作完之平面揚聲器進行聲壓曲線量測，其實驗值與模擬分析之理論值進行比對，以驗證理論分析的正確性。本研究在所有平面揚聲器實驗結果，生物纖維薄膜以有懸邊厚度L、烘乾溫度50℃做為圓形平面揚聲器之振膜其聲壓曲線為最佳，以期未來在選擇製作圓形平面揚聲器之振膜，可作為參考選用。

This study investigated the characteristics of a biocellulose membrane on flat-panel speakers and the effects of various manufacturing parameters of the biocellulose membrane on the speaker membrane. In this study, we designed and manufactured a miniature circular flat-panel speaker (ψ 16 mm×H 7.8 mm) and a rectangular flat-panel speaker (L 162 mm × W 115 mm × H 10 mm).To investigate the feasibility of applying the biocellulose membrane to flat-panel speakers, we examined the manufacturing parameters of coating, drying temperature and thickness. We obtained their mechanical properties (Young's modulus and Poisson's ratio) by using the tensile test and researching the sound pressure level (SPL) curve of the flat-panel speakers to determine the optimal manufacturing parameters for the biocellulose membrane. ANSYS software was used to calculate the vibration amplitude and phase angle, which were then substituted into the SPL formula. Fortran software was used to calculate the SPL. We manufactured flat-panel speakers to measure the SPL curves and compared the experimental results with simulation results to verify the accuracy of theoretical analysis.Our experiment results showed that the optimal biocellulose membrane for miniature circular flat-panel speakers has a thickness L and is dried at a temperature of 50oC. The optimal manufacturing parameters established for the biocelleular embrane applied to circular flat-panel speakers can be used as a reference.