磁流變流體應用在可變焦光學物鏡之研究

Development Of Multi-Focal Fresnel Lens Using Magnetroheological Fluid

吳家棋(Chia-Chi Wu)

指導教授 ： 方煒

國立臺灣大學/生物資源暨農學院/生物產業機電工程學研究所/碩士(2004年)

https://doi.org/10.6342/NTU.2004.01870

摘要

本研究旨在探討磁流變流體應用在繞射光學元件的設計與其應用於可變焦光學讀取頭的可行性。製程上使用類似微機電製程中的LIGA(Lithographie GaVanoformung Abformung)翻模方法，以矽晶片為母模，以PDMS為鑄造材料的微形模造技術，製作出所需的Fresnel繞射光學元件。
首先將磁流變流體填入PDMS所製作的透鏡中，其微流道呈現Fresnel波帶結構，應用磁流變流體薄膜在垂直磁場下對光的穿透率會有變化。其次量測填充有磁流變流體的PDMS繞射元件在有無給與外加磁場下光具組焦距的變化。 最後使用軟體MATLAB來做計
算波帶片的數值模擬與控制量測設備的動作。
實驗結果顯示磁流變流體變焦透鏡確實有變焦的能力，當未給予外加磁場時量測出光具組的焦距為35.7 mm，當給予磁通量為240高斯的外加磁場，量測出焦距為35.1 mm。

關鍵字

磁流變流體 ； 波帶片 ； 變焦透鏡

並列摘要

The purpose of this study is to design a diffraction optical element using magnetorheological fluid for a switchable object lens used in optical pickup head. The micro fresnel structure was fabricated using micro-molding of silica wafer and made of PDMS.
Switchable lens was consists of a PDMS fresnel zone plate and a PDMS convex lens. The channels of the micro fresnel plate were filled with magnetorheological fluid. The light transmittance of the switchable lens will varied depends on the existence of the vertical magnetic field applied to the lens. The focus of the PDMS lens were measured when with or without magnetic field. MATLAB software was used to simulate the intensity distribution on the fresnel zone plate and to control the movement of two stepping motors in controlling the position of the focusing screen.
An electromagnetic controlled focus-switchable lens was developed in this study. The results showed that the focus of PDMS lens will change from 35.7 mm to 35.1 mm when a 240 gauss magnetic field was applied.

並列關鍵字

micro lens ； ferro fluid ； zone plate

參考文獻

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