類菲涅爾型電極可變焦距液晶透鏡的模擬與製作

Abstract

本論文主要介紹Fresnel type液晶透鏡的模擬以及製程。模擬部分主要介紹如何去模擬透過Fresnel 透鏡形狀的電極對液晶層加以電壓後對於液晶層的影響。為了讓所研究可以應用在VR/AR使用者的近視校正功能，我們設計了大於瞳孔的12mm液晶透鏡。為了比傳統液晶透鏡達到更大的屈光度，我們將GRIN透鏡以及Fresnel透鏡的概念結合在一起。在經過模擬過後，我們利用精密加工去作出電極的模具，然後用PDMS以及NOA65去製作透明的Fresnel透鏡狀結構。在上面旋轉徒步上PEDOT:PSS後，我們就可以得到Fresnel type電極，接下來利用SU-8去將電極填平並將其與ITO電極塗佈上PVA後封裝，藉此就可以得到Fresnel type液晶透鏡。接著我們利用光學系統以及CMOS去觀測牛頓環，CCD去觀測透鏡的成像。透過牛頓環數的計算我們可以得到這個透鏡可以有-8.9屈光度的折光能力。可在VR/AR的近視校正以及其他可變焦可放大光學系統上的有所應用。

In this research, the simulation and the fabrication of the Fresnel-type liquid crystal lens is demonstrated. The simulation is about how to simulate how Fresnel-type electrodes which is being applied voltage will affect the liquid crystal cell. We hope the lens can solve the problem of nearsighted user of VR/AR. So we would like to design a lens with a diameter of 12 mm which can cover human’s pupils. We choose to make a GRIN lens with Fresnel type to gain more diopters. After the simulation of the lens, we use Precision Machining to make the mold of the Fresnel-type electrodes and mold it with PDMS and NOA65 to make a transparent Fresnel lens structure. After we spin-coated PEDOT:PSS on the lens, we can get a Fresnel type electrode. Then we’ll fill in the electrode with SU-8 photoresist and assemble it with a plastic spacer and ITO glass. After the liquid crystal is filled within the gap between SU-8 photoresist and ITO glass, we can finally get a prototype of a Fresnel-type liquid crystal lens. The interference pattern is measured by CCD and the imaging of the lens is observed by CMOS. We can measure the optical power by interference pattern. The diopter ranges from 0 to 8.9 Diopters and is good for nearsighted correction in VR/AR system and also for optical zoom system and focus-tunable lens applications.