低溫沈積類鑽碳薄膜於PET耳機振動膜之頻率響應研究

A Study of frequency response of PET earphone vibration diaphragm with Low-temperature Deposited DLC Thin Films

陳廷仁(Ting-Jen Chen)

指導教授 ： 林啟瑞 ； 蘇春熺

國立臺北科技大學/機電學院/機電整合研究所/碩士(2007年)

https://doi.org/10.6841/NTUT.2007.00137

摘要

鑽石是揚聲器振動膜最好的材料，但是以化學氣相沈積的製程製造鑽石膜會比較困難。類鑽碳膜的特性類似於鑽石，以物理氣相沈積製造類鑽碳膜也比較容易，因此類鑽碳膜適合做為高品質揚聲器振動膜的材料。本研究將類鑽碳薄膜沈積在振動膜凸起表面，以提升耳機高頻頻率響應性能，得到更高品質的耳機。本研究的頻率響應量測系統的製作及組裝，以及耳機的組裝，皆為自己動手完成，且頻率響應性能分析也是自己著手進行。
類鑽碳膜的低密度(與其它做為振動膜材料的密度相比)及高剛性，可以改善揚聲器高頻的頻率響應性能。本研究以物理氣相沈積製程的射頻磁控濺鍍法及奈米鑽石靶材，以低工作溫度(低於80℃)及低偏壓，在耳機振動膜(PET;聚對苯二甲酸乙二醇酯)上沈積低密度、輕、薄的類鑽碳薄膜，以提升耳機在高頻的頻率響應性能。鍍膜區域分為全域鍍膜、中間區域鍍膜及外圍區域鍍膜三種振動膜形狀設計，比較各個的頻率響應性能。振動膜分析方面，以頻率響應量測系統得到頻率響應曲線圖，成份及鍵結分析以ESCA量測，另外為了更加了解振動膜上的類鑽碳薄膜性質，以PET板及Si wafer做為基材，取得類鑽碳薄膜的表面形貌(AFM)、光學性能及厚度(光學特性檢測系統)。頻率響應分析結果顯示，與未鍍膜振動膜相比，以全域鍍膜的振動膜，在6 kHz~9 kHz之間，提升4dB左右，9 kHz~14 kHz 之間提升了1dB，14 kHz~18 kHz提升了4 dB，但低音共振頻率變高。外圍及中間區域鍍膜的振動膜，9 kHz~14 kHz 分別提升2 dB及4 dB，在14 kHz~18 kHz分別提升5 dB及4 dB，在6 kHz~9 kHz之間的頻率響應沒有獲得改善，且中間區域鍍膜的振動膜較差，而兩者的低音共振頻率沒有改變。

關鍵字

聚對苯二甲酸乙二醇酯 ； 類鑽碳薄膜 ； 頻率響應 ； 耳機振動膜

並列摘要

Diamond is the best material of loudspeaker vibration diaphragm, but the fabrication of diamond is very difficult by CVD. Diamond-like carbon (DLC) film properties are similar to diamond and easier to fabrication by PVD, so DLC film is an adaptable material for loudspeaker diaphragm. The study shows depositing DLC film on earphone vibration diaphragm (PET; Polyethylene terephthalate) raised surface to improve the earphone frequency response performance in high frequency and get the higher quality earphone. The manufacture and assembly of the study’s frequency response measure system and the assembly of the earphone are all done by myself, and the frequency response analysis is been done by myself.
The low density (compare to other vibration diaphragm material) and high rigidity of DLC film can improve loudspeaker frequency response performance in high frequency. The study that uses the R.F. Magnetron Sputtering of Physical vapor deposition (PVD) process and nanometer diamond target deposits low density, light, thin DLC film on earphone vibration diaphragm (Polyethylene terephthalate ; PET) at low work temperature and low bias to improve earphone frequency response in high frequency. The coating area divides into three kinds of vibration diaphragm shape designs that are whole area coating, center area coating and outside area coating to compare the frequency response performance. The analysis of vibration diaphragm, the study uses frequency response measure system to get frequency response curve figure and get composition and bonding analysis by ESCA. In addition to a better understanding of DLC film(on vibration diaphragm)properties, the study grow DLC films on PET board and Si wafer sample to get the surface morphology(AFM), optical performance and thickness(optical characteristic measurement system) of DLC film. The frequency response analysis results show, compare with no coating vibration diaphragm, the vibration diaphragm deposited whole area DLC film promotes about four dB between 6 kHz~9 kHz, one dB between 9 kHz~14 kHz, four dB between 14 kHz~18 kHz, but the bass resonance frequency changes high. The vibration diaphragm of outside area coating and center area coating separately promote 2dB and 4 dB in 9 kHz~14 kHz, 5 dB and 4 dB in 14 kHz~18 kHz, the frequency response between 6 kHz~9 kHz isn’t improve, and the vibration diaphragm of center area coating is worse, and both bass resonance frequency have not changed.

並列關鍵字

Polyethylene terephthalate(PET) ； Diamond-Like Carbon thin film(DLC) ； Frequency Response(FR) ； Earphone Vibration diaphragm

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