設計與製作應用於光學讀寫頭之微非球面透鏡

Design and Fabrication of Micro Aspherical Lens for Optical Pickup Head

陳炯廷(Chiung-Ting Chen)

指導教授 ： 曾繁根 ； 錢景常

國立清華大學/工學院/微機電工程研究所/碩士(2006年)

摘要

光學讀寫頭為光碟機中關鍵元件之一，而光學讀寫頭中，聚焦透鏡負責聚焦光線產生光點來讀取或寫入資料於光碟片上，一個聚焦透鏡的優劣亦影響整個光學讀寫頭性能。
本文提出以微機電之製程技術，來製作光學讀寫頭之微聚焦透鏡。透鏡材料使用可固化高分子液體SU-8，藉由材料表面張力作用來控制透鏡表面平整度，並搭配下部電極之電濕潤效應與上部電極之靜電吸引效應，達到側向與縱向二微可調變之微非球面透鏡，以減少球面像差影響得到更好的聚焦效果，而透鏡外貌可利用UV光照射透鏡材料SU-8將其固化成型。
隨著靜電力吸引漸增，得到透鏡外貌從球形向上吸引為拋物線甚至錐形，固化後量測其光學性質。結果得到當透鏡外貌從球形改變至拋物線甚至接近錐形，數值孔徑變化從0.49增至0.66且聚焦光點大小從2.302 μm減小為1.166 μm。在改善雜散光問題後，得到更好的聚焦效果為0.778 μm，此非球面透鏡可以運用於ㄧ般光學讀寫頭之聚焦透鏡上。

關鍵字

光學讀寫頭 ； 聚焦透鏡 ； 非球面透鏡 ； 二維靜電力

並列摘要

This paper proposes a novel design concept and fabrication method of micro aspherical lens for Optical pickup head.
Gradient-Electrostatic-Forces (GEF) were employed to shape liquid polymer from hemisphere into parabolic or near cone shape, and the shape can be fixed by a UV curing process in situ.
As a result, the numerical aperture for this lens was varied from 0.49 at spherical shape into 0.66 at near parabolic shape and the focused light spot size (by red light 632.8nm) was reduced from 2.302 μm into 1.166 μm, suitalbe for the need of objective lenses with high mumerical apertures and resolution. Very high quality focus effects, 0.778 μm spot size (by red light 632.8nm), and 0.66 NA were obtained at an optimized shape of the GEF lens, which is compatible to those of the commercial DVD objective lens.

並列關鍵字

Optical pickup head ； Objective lens ； Aspherical lens ； 2D Electrostatic forces

參考文獻

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