3D電極可變焦距大孔徑液晶透鏡之模擬和製作

Abstract

本論文主要介紹GRIN lens type大孔徑液晶透鏡的模擬方法以及相對簡單且成本較低的製程方法。模擬的部分主要介紹如何設計出立體漸變的電極結構產生漸變之電場分布使液晶分子旋轉至特定角度，讓其感受到等校於類似凹透鏡之相位曲線以達到散焦之效果。為了讓此研究可以應用在VR/AR使用者的近視校正上，我們設計了孔徑大約等於瞳孔大小的6mm 且其屈光度為 -5之液晶透鏡。在經過嚴謹準確的模擬之後，我們利用精密加工製作出具有立體漸變的電極結構之模具，接著利用 PDMS 以及 NOA65 製作透明且具有所設計之立體電極結構，之後在其表面旋轉塗佈上透明電極 PEDOT:PSS 後，就能得到所設計之立體電極，再來利用 NOA65 將電極填平並將其和具有 ITO 電極之玻璃基板塗佈上 PVA 後封裝，最後再灌入液晶,就可以得到我們所設計的大孔徑液晶透鏡。接著我們利用 CCD 觀察干涉條紋驗證在不同電壓下其屈光度和模擬結果有無差異，之後設計幾個實驗去觀測此液晶透鏡的成像效果如何。此元件我們認為可在 VR/AR 的近視校正以及其他可變焦之光學系統上的有所應用。

In this thesis, the simulation and the fabrication of the GRIN lens-type liquid crystal lens is demonstrated. The simulation part is about how to design the 3D gradient electrode structure to generate the gradient electric field that makes each LC director orient in specific orientation to obtain the defocus effect. It is expected that this research can solve the problem of nearsighted users of VR/AR. We design a liquid crystal lens which has an optical power of -5 diopters and the aperture is 6 mm. After rigorous and accurate simulation, we use Precision Machining to fabricate the aluminum mold which has the designed 3D structure and mold it with PDMS and NOA65 to make a transparent 3D structure. After we spin coated PEDOT:PSS on the surface, we can get the designed 3D electrode. Then we’ll flatten the surface of 3D electrode with NOA65 and assemble it with another ITO glass substrate. Finally, the liquid crystal is injected in the gap between two substrates, and we can finally obtain our designed large aperture liquid crystal lens. Afterwards, we use CCD to observe the interference fringes to verify whether the diopters are different with simulation under different voltages. Then we set up experimental tools to measure the image properties of the LC lens. This component is good for nearsighted correction in VR/AR system and also for optical zoom system and focus-tunable lens applications.