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標題: | 具有週期性結構之液晶裝置的研究 A Study of LC Devices with Periodical Structures |
作者: | Jyun-Yu Chen 陳駿瑜 |
指導教授: | 蔡永傑(Wing-Kit Choi) |
關鍵字: | 半穿透半反射式顯示器,週期性電極,法布立-培若干涉儀,高分子穩定型液晶,高分子分散型液晶,液晶,光開關,固化電壓, Transflective display,periodical electrode,Fabry-Perot cavity,polymer stabilized liquid crystal (PSLC),polymer dispersed liquid crystal (PDLC),liquid crystal,optical shutter, curing voltage, |
出版年 : | 2014 |
學位: | 碩士 |
摘要: | 顯示器技術一直是近代一個熱門的課題,從早期CRT到現在液晶顯示器的普遍化、大尺寸化,無一不投入許多研究的人力及心血。近年由於可攜式行動裝置大量問世,從智慧型手機至智慧型手錶,人們的生活即將被科技產品所涵蓋,顯示器絕對是舉足輕重的一環。由於可攜式行動裝置的使用環境大部分具有強烈的環境光源(Ambient Light),而環境光源會導致大部分穿透式顯示器(Transmissive LCD)出現蓋光效應(Washed Out Effect),這時候反射式顯示器(Reflective LCD)因應而生,雖然反射式顯示器不容易被環境光源影響,但卻常常發生對比度不足以及亮度不足的問題,因為反射式顯示器的光源主要來自於環境光源,當處於室內時.環境光源薄弱,即會造成反射式顯示器的光源大幅下降,而科研人員結合了這兩種顯示器的優點發明了半穿透半反射顯示器(Transflective LCD),不但擁有穿透式顯示器的背光源,也能像反射式顯示器在室外有良好的顯示品質並且節省能源;但半穿透半反射顯示器製作上相較於其他兩者較為困難,普遍依照結構分為:單間隙半穿透半反射顯示器(Single Cell Gap Transflective LCD)以及雙間隙半穿透半反射顯示器(Double Cell Gap Transflective LCD)。雙間隙半穿透半反射式顯示器主要通過不同間隙使得穿透區以及反射區的光電曲線(Electro-Optic Curve)達到匹配,但製程上複雜許多,同時也會耗費許多成本;而單間隙雖然製程較為簡單,但因為間隙相同,較難以使光電曲線互相匹配。本篇論文利用電極的週期性結構設計使得反射區的光電曲線能漸漸調整匹配至穿透區,同時也利用高分子穩定型液晶(Polymer Stabilized Liquid Crystal, PSLC)在聚合過程時施加電壓,使得液晶獲得預傾角,進而調整光電曲線,而這樣的方法相較其他的方法簡單且便利許多。
除了顯示器的部分,我們討論了另外一種週期性結構的液晶裝置_全像高分子分散型液晶(Holographic Polymer Dispersed Liquid Crystal, HPDLC),我們利用雙光干涉製造出液晶光柵,而這樣的材料可以拿來記錄全像影像資訊,並且利用外加電壓改變液晶的排列方向,使液晶折射率改變,作出可電壓調變的全像片或是光電濾波器、可調式微透鏡、波長多功器等等應用。而我們成功製作出週期約554nm的HPDLC,繞射效率約為7.39%。 而最後在附錄部分我們則討論利用高濃度高分子聚合物單體所調製的高分子聚合物分散液晶來製作法布立-培若共振腔(Fabry-Perot Cavity)。我們想利用本身穿透率高、折射率可調以及反應速度快的特性,在共振腔內藉由給予不同的電壓來改變特定波長的穿透率(波長調變),來彌補對比不足的缺點,同時也能作為一個十分優秀的特定波長光開關(Optical Shutter)。 Monitor technology has been a popular topic over the recent years, from the earlier CRT stages to the gradually common liquid crystal display (LCD), which has been also expanding in size; manpower and resources have been invested in all of the mentioned technology. In the past few years, portable mobile devices are introduced to the world in large numbers, ranging from smartphones to smartwatches. People’s lives are about to merge with technology products, and monitors are definitely an essential element. Portable devices are usually used in environments with strong ambient light, the light will cause most of the Transmissive LCD to show a washed out effect; the said effect resulted in the production of the Reflective LCD. Although the Reflective LCD is not easily affected by ambient light, problems such as an insufficient contrast ratio or weak brightness occurs often, because the light source of Reflective LCD comes mainly from ambient light. When the device is indoors, the weak ambient light causes the light source to decrease largely for Reflective LCD. Technology researchers then combined the strengths of the two LCD’s and invented the Transflective LCD, which not only possesses the back light module of the Transmissive LCD, but is also able to display images of good quality outdoors and save power like the Reflective LCD. But the Transflective LCD is more difficult to produce than the two other LCD’s, and is divided into two types according to the structures: Single Cell Gap Transflective LCD and Double Cell Gap Transflective LCD. Double Cell Gap Transflective LCD enables the electro-optic curves in the transmissive region and reflective region to match through different cell gaps, but it is complicated to fabricate and will cost more to produce. The Single Cell Gap Transflective LCD is easier to produce, but because the cell gaps are the same, it is more difficult to match the electro-optic curves with each other. This thesis allows the electro-optic curves in the reflective region to gradually adapt and match the transmissive region via the periodical electrode structure, also to achieve a pre-tilt angle by applying voltage to the curing process of the Polymer Stabilized Liquid Crystal (PSLC), this allows the adjustment of the electro-optic curves and is a much simpler and convenient way compared to others. We also discuss another periodical LC device called Holographic Polymer Dispersed Liquid Crystal (HPDLC). We use two-beam interference lithography to fabricate HPDLC; Also, HPDLC can be used to record holography image. Otherwise, we can apply electric field to change the alignment of LC. That is to say the effective refraction index can be changed. This device can be used in Holography, focus-tunable microlens, and wavelength division multiplexing etc. The last chapter discusses the PDLC produced by high concentration polymer monomer, and how Fabry-Perot Cavity is produced by the latter. We want to take advantage of the high transmission, adjustable reflection and the high-speed reaction to change the transmission of specific wavelengths by applying different voltage within the resonator. This will be used to complement the shortcomings and serve as an excellent optical shutter. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/55456 |
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顯示於系所單位: | 光電工程學研究所 |
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