像散式光學量測系統抗飄移電路之最佳化

Astigmatic Measuring Optical Measurement System Optimized Anti-Drift Circuit

林明山(M. S. Lin) ； 胡恩德(E. T. Hwu) ； 宋真坦(J. T. Sung)

《中華科技大學學報》 58期 (2014/01) Pp. 61-79

摘要

像散式讀取頭（Optical Pickup Unit，OPU）為光碟機讀取光碟片資料軌的核心元件。OPU具備奈米級線性位移量測解析度與角秒級角度解析度［1］，許多研究已成功利用數位影音光碟機DVD讀取頭進行精密量測，如：光像散式原子力顯微鏡［2］、共振頻檢測系統、像散式光學干涉儀。僅管讀取頭可量測到奈米級的位移，然而微小的環境溫度變化以及機械應力皆可使系統機構產生微小變形，造成訊號緩慢飄移而影響測量的準確度。此類機構的緩慢飄移，可透過音圈馬達（Voice Coil Motor，VCM）的抗飄移補償［3］，使系統維持在量測範圍內。本研究運用最佳化電路實現自動對準與抗飄移補償電路機制，可有效降低環境變化造成之訊號飄移，使讀取頭維持在最佳線性區斜率最陡範圍內，抑制飄移誤差，並提高精確度。

關鍵字

像散式讀取頭 ； 音圈馬達 ； 抗飄移補償機制 ； 聚焦誤差訊號

並列摘要

Optical pickup unit (OPU) is the main component of CD-ROM, which can be used to read data from CD, has astigmatic measuring techniques and milliarcsecond resolution [1]. In recent years, multifunctional DVD devices play an important role in many nanoscale measurement systems. For example, Astigmatism-based Atomic Force Microscopes [2], resonance frequency investigation system and astigmatic optical interferometer measurement.Nevertheless, the drift of displacement signals often reduces the measuring accuracy. Slight variation of environmental temperature and mechanical stress cause tiny deformation in OPU. Moreover, the continuing drift makes the signal exceed the normal measurement range and interrupt system. The signal drift can be modified through Voice Coil Motor (VCM) compensating mechanism. [3] The compensating mechanism can maintain the Focus Error Signal (FES) in linear region. The goal of the thesis is utilizing the optimal electrical circuit to realize auto alignment and anti-drift feedback circuit. The method can reduce the drift phenomenon causing from environment, improve the OPU stability, keep the measurement in the steepest linear region, reduce the error and improve the measuring efficiency.

並列關鍵字

Optical Pickup Unit ； Voice Coil Motor ； Anti-drift compensation ； Focus Error Signal