近場光碟片之振動分析與實驗

Abstract

近場光碟機為一突破光學繞射的資料貯存裝置，貯存容量遠大於目前光碟機數十倍，所採用的讀寫機構造類似目前的硬碟機，讀寫頭利用空氣軸承飛行於碟片上方約20nm。穩定的飛行利於讀寫頭的尋軌、循軌和聚焦，但碟片的缺陷，軸承的間隙，讀寫頭所施予的空氣壓力，都會造成碟片的振動。 本研究主要是探討近場光碟機的碟片振動，並探討碟片自然頻率和楊氏係數的關係，以利碟片材質的選用，再以ANSYS和DADS軟體建立碟片模型，分析碟片在特定轉速時的振動量，以及碟片啟動時的暫態情形和不同轉速間碟片的振動比較，並輔以雷射都卜勒干涉儀驗證，本研究成果將有助於從事光碟機讀寫頭設計與控制。

Near-Field Optical Disk Drive (NFODD) is a promising device for data storage with capacity much larger than current DVD-ROMs. The flying pickup head in NFODD has to fly stably around 20nm height above a disk surface by means of air bearing. Stable flight is required to undergo track-seeking and focusing. However, disk flaws, bearing clearance, spindle motor and air bearing cause the disk to vibrate. This research aims to investigate disk vibration of NFODD. Flexible disk models are generated in the finite element and multibody dynamics softwares to analyze vibration modes and deformation during disk rotation. Experiments are carried out using a Laser Doppler Vibrometer to compare simulation results.