具多圈不等寬度電極之液晶透鏡設計與實驗驗證

Abstract

本論文主軸為設計並製作一新型變焦液晶透鏡元件，利用多圈不等寬度電極 彌補習知單孔徑變焦液晶透鏡因孔徑過大造成中央折射率分佈不若漸進式折射率 透鏡完美之缺憾，且針對折射率分佈所需變異較劇之部分對電極寬度作最佳化， 以期更接近完美漸進式折射率分佈；並將電極設計於液晶層內部，可大大縮小所 需之外加驅動電壓，減輕電源管理之負擔，另外於電極與液晶層之間鍍上一層絕 緣層以使電場分佈趨於平順。模擬部分以Dimos .2D 液晶模擬軟體所得之電場與 折射率分佈推算焦距變化並與新型變焦液晶透鏡元件之實體實驗結果作比較與驗 證。另外，本論文亦研究利用所設計之新型變焦液晶透鏡元件取代變焦鏡群組其 中之一片傳統正型透鏡，以節省變焦透鏡群組為達到變焦效果所需之多餘作動行 程。將新型變焦液晶透鏡與手機照相模組作結合，可減少變焦模組之體積，使手 機更能達成輕薄短小的要求，以提升其商業價值。

The main topic of this study is to design a novel liquid crystal (LC) lens device with multiple ring electrodes in unequal widths to improve the refractive index distribution while the conventional LC lens with a hole-patterned electrode performs as a non-gradient index lens. The widths of the multiple ring electrodes are optimized to render the index distribution leading to perfect focusing, while the conventional LC lens with a hole-patterned electrode design only provides less perfect focusing. The electrodes of this LC lens are designed at inner surfaces of the cell to decrease the driving voltages for the same level of focusing power. In order to smooth the electric field distribution, a dielectric layer is coated between electrodes and the LC layer. The simulation software, DIMOS .2D, is utilized to evaluate the LC lens in the distribution of refractive index and the resulted focal length; then verified by experimental measurement and also compared with those conventional lenses. In addition, this work presents a brief study of adding one lens to a zoom system with the proposed LC lens to save the total axial size of a typical zooming lens module. It is verified that the combination of the proposed LC lens and the mobile camera module could reduce the volume and elevate the commercial value of the lens module.