壓電管致動器應用於近場光碟機飛行讀寫頭之動態特性

Abstract

近場光碟機為了滿足近場光學的要求，必須在極接近碟片反射面約50奈米處做讀寫的動作。然而在如此近距離下進行尋軌與對焦，關鍵在於飛行讀寫頭的設計。本研究所設計的飛行讀寫頭利用壓電管作為雙軸致動器，藉以執行對焦與尋軌的動作。本研究利用有限元素法分析雙軸致動器的靜態與動態模擬，並與文獻中的理論公式和實驗結果驗證。然後從事懸吊組件與讀取頭機構之靜態與動態分析，以觀察雙軸致動器執行對焦與尋軌時所造成懸吊組件的變形，並與實驗結果驗證 。由分析的結果可知，模擬結果和理論公式均與實驗結果ㄧ致。最後根據實驗與文獻的結果，推導壓電管致動器應用於近場光碟機讀寫頭的追蹤誤差。

In order to meet requirements of near-field optics, a flying pickup head in near-field optical disk drives has to fly stably around 50 nm above a disk surface so as to read/write disk data. Hence, an actuator is required to undergo very high precision motion at such small spacing. This study aims to design a dual-axes actuator using a piezotube in order to perform near-field track-seeking and focusing. This study uses the finite element method to analyze static and dynamic models of a dual-axes actuator and compares with the literature and experimental results. Static and dynamic models of the suspension assembly and pickup head mechanism during focusing and track-seeking are established to calculate deformation of the suspension assembly, which are compared with experimental results. Computational results consist with the theoretical and experimental results. Finally, based on system identification results, this study derives equations of motion for the pickup head mechanism, and hence investigates tracking error in the presence of sinusoidal deformation of disk surface and sinusoidal disturbance force.