共路徑雷射光學尺

Common-path Laser Encoder

楊子毅(Zi-Yi Yang)

指導教授 ： 吳乾埼

淡江大學/工學院/機械與機電工程學系碩士班/碩士(2010年)

https://doi.org/10.6846/TKU.2010.00266

摘要

繞繞射式雷射光學尺突破光波繞射極限，可提供奈米級的位移解析度，是奈米量測應用極具潛力的工具。習用的雷射光學尺光路架構多是麥克森干涉儀型式，其量測光束與參考光束的路徑不同，環境擾動的影響會直接進入量測訊號裡頭，無法消除，使得雷射光學尺的準確性大幅下降。
本文提出創新共路徑繞射式雷射光學尺架構，它可有效消減環境擾動所造成的影響，提高量測訊號的穩定性。本文介紹共路徑雷射光學尺量測原理，以都卜勒移頻效應與光柵干涉術的理論基礎，設計出位移量測裝置，其原理則是利用光柵產生位移將會引入相位變化至各階繞射光，並且使不同階數繞射光重疊產生干涉，透過我們所開發Labview軟體的應用程式，作訊號處理將相位差轉換為位移量輸出。本文中也針對量測誤差進行討論，其中包含系統誤差及隨機誤差兩大類，提供未來對於此項研究可以進一步改善。
實驗分析顯示該雷射光學尺靈敏度為0.225 /nm、理想電子解析度達到0.0244nm，在奈米應用上極具潛力。

關鍵字

雷射光學尺 ； 共路徑 ； 解相位 ； 都卜勒效應 ； 光柵

並列摘要

Diffractive laser encoders overcome the diffraction limit of optical waves. They can provide nano-scale displacement resolution, and will have great potential for nano-metrology applications. The optical configurations of used laser encoders are Michelson’s type with different paths between the measurement beam and reference beam. The environmental disturbance can directly enter the measured signals and cannot be essentially slashed. Thus the accuracy of the used laser encoders becomes dramatically worse.
This paper brings up the construction of new common-path diffraction lsaer encoder. It can effectively slash the effect of the environmental disturbance and enhance the stability of measured signals. This work describe common-path diffractive laser encoder measurement principle. The basic theories affected by Doppler effect and grating interferometry. Design a facility for displacement measurement. The principle shows that the displacement is occurred by utilizing the grating and it leads the phase variate to each order diffraction beam, and it makes the different order diffraction beam overlap to produce the interference. Besides, through the application of Labview, it handles the signals to transform the phase difference into the displacement. We will also discuss the errors of the measurement in this paper, and the errors include the systematic error and the random error. These errors can be improved further for the research in the future.
Experimental analyzes demonstrate that it has a sensitivity of 0.225 /nm and a theoretical predication displacement resolution of 0.0244 nm. It has promising potential for nanotechnology applications.

並列關鍵字

laser encoder ； common-path ； phase decoding ； Doppler effect ； grating

參考文獻

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