高聚焦能力多驅動電極柱狀調變式液晶透鏡

Abstract

傳統的透鏡組由於是利用機械化的移動控制來改變透鏡間的距離，進而改變其聚焦能力，因此需要有足夠的空間來放置透鏡組。然而，在現今的照相手機市場裡，輕、薄、短、小是成為商品化的基本條件，傳統的透鏡無法滿足如此的需求，所以現今的照相手機在照相功能上是以數位變焦為主，利用數位化的技術來達到聚焦的功能，因此，其聚焦後的影像品質仍不及使用光學變焦的傳統相機。液晶透鏡具有使用電力控制即可達到光學變焦的特性，不需要額外的空間作機械式的調變，因此十分適合取代照相手機鏡頭模組中的透鏡。 本論文首先透過模擬軟體2DimMOS及MatLab建立數學模型，針對液晶透鏡上的電極圖騰設計與成像品質的關係作深入的分析討論，並提出多柱狀電極的設計來改善液晶透鏡的成像品質。接著，我們實際做出成品並與模擬結果作驗證，發現多柱狀電極因為可以分區的控制液晶轉向，因此聚焦能力遠比傳統雙電極液晶透鏡好且需要供給的電壓能量更低。在反應速度方面，我們利用提供電極短時間的高驅動電壓去幫助液晶分子的起始轉動，進而改善液晶透鏡的反應速度。此研究也更有利於將液晶透鏡應用於照相手機上。

The conventional tunable glass lenses are operated by adjusting the distance between the lenses to change the focal length. The issues of conventional tunable glass lenses are bulky and heavy. However, the compact size and light weight are very critical for the camera phone. Therefore, most of the commercial camera phones are only use the digital signal processing to simulate the zooming image, and the zooming image quality is not good enough yet. To overcome these issues, the tunable-focal lens has been developed to improve the image quality. The LC lens is electrically tunable and no moving mechanical part, which means they are compact and light weight. Therefore, the LC lens is very suitable for the application of camera phone. In this thesis, the simulation model to characterize the feature of the LC lens with electrode pattern has been established by the commercial simulation software 2DiMOS and MATLAB. By analyzing the electrode pattern, we propose the multi-electrode driven cylindrical structure with 9 electrodes and the ratio of W_E/W_S is 1 where W_E=W_S=88μm to improve the focusing quality. The experiment results show the multi-electrode has smaller FWHM value of focusing performance with smaller applied voltage than the double-electrode structure. Moreover, in order to improve the response time, large applied voltage was given to the outer large electrodes for a short time interval to help LC molecule orientation. The response time was improved by 70%. These results are helpful for applying the LC lens for the camera phone applications.