一種利用液晶透鏡之光學成像系統的對焦與光學變焦研究

Abstract

本文探討一種利用液晶透鏡構成之光學成像系統，並研究系統中對焦與變焦的功能。系統結構由傳統固態透鏡組成之光學變焦系統演變而來，利用可電控調焦之液晶透鏡鏡組，分別電控改變對焦平面以及系統影像的縮放。本論文中，首先探討系統的對焦鏡組之對焦條件及變焦鏡組改變影像放大率之能力，接著分析系統參數，包括液晶透鏡聚焦能力、對焦鏡組像平面之選擇以及系統長度對於系統縮放比的影響。接著根據分析，我們利用三片液晶透鏡設計出對焦與光學變焦功能可分別操作之電控光學成像系統，其系統長度在10公分的情況下，能達成對焦範圍從無窮遠處到10公分，系統縮放比皆維持7:1，並可電控調變影像連續縮放之功能。未來可應用在各式需求體積小、重量輕之光學成像系統上的裝置，如智慧型手機，Google glasses等。

An optical image system using liquid crystal lenses with separated focusing and zooming function is demonstrated. The structure of system originated from traditional optical zoom system, and using tunable liquid crystal lens groups to change focus plane and image magnification. In this thesis, we start from discussing system’s focusing lens condition and the magnification. Then, analyze the impact of the system parameters, including tunable lens power range of liquid crystal lenses, the image position of focusing lens and the system length. Based on the analysis, we design an optical image system with separated focusing and zooming function, having the same zoom ratio (7:1) over the objective distance from 10cm to infinity and the system length 10cm. The potential applications are the devices that demands compact and light optical zoom systems such as smart phones and Google glasses.