電機資訊學院: 電子工程學研究所指導教授: 楊英杰; 陳殿榮林冠中Lin, Guan-JhongGuan-JhongLin2017-03-062018-07-102017-03-062018-07-102015http://ntur.lib.ntu.edu.tw//handle/246246/276074使用高分子網(Polymer Networks)於平面驅動垂直排列(In-Plane Switching Vertically Aligned)的液晶(Liquid Crystal)元件上，將有助於穩定元件的分子結構並改變其原本的光電特性。本論文選取三種不同的單體材料，開發出各自穩定的高分子形貌於元件的玻璃基板表面上，並分析整體元件的物理與光電特性。其中，具有平面分布交鏈型(Planar Cross-Linking)的高分子形貌將可導入較強的錨定效應(Anchoring Effect)於液晶元件中。這將有效地控制液晶分子的排列與其結構，並改善元件的切換速度(Switching Response)。此外，高電壓的驅動下(Overdrive)，高分子錨定效應可抑制因液晶分子轉動(Reorientation)所帶來的暫態效應 (配向轉移(Alignment Transformation)與輸出光的跳動(Transmittance Bounce))，實現出快速響應的液晶光電元件。雖然強錨定可以改善元件的響應速度，但過強的強錨定效應將會加大元件的操作電壓，故而在設計快速響應的光電顯示元件時，需同時考量高分子材料所帶來的錨定能與操作電壓值。結合上述的研究成果，我們從中歸納出一適當的單體材料(Biphenyl Diacrylate)與其混合濃度(2 wt.%)，並在高分子固化(Curing)過程中施加一不均勻的垂直電場(Non-Uniform Vertical Electric Field)於元件上，製作出具有多區域預傾排列的液晶分子結構(Multi-Pretilt Structure)。藉由此分子結構，將可有效降低元件的驅動電壓，並可大幅縮短明暗的切換時間(提升36 %)與灰階(Gray-Level)響應所需的時間(提升 > 64 %)。Polymer networks are employed in vertically aligned liquid crystal (VA LC) cells to stabilize the LC molecular configuration under the in-plane switching (IPS) electric field driving. Three kinds of polymer morphologies are well developed and anchored on the glass substrate surface. With the planar cross-linking polymer morphology, the transformed electro-optical properties of the cell, composed of positive nematic LC and biphenyl diacrylate monomer, are revealed. As compared to the pure LC cells, this type of LC/polymer cell shows fast switching and gray-level responses at a low driving voltage (≤ 12 V), which is attributed to the increased anchoring effect that effectively governs the LC molecular reorientation. In addition, the alignment transformation and transmittance bounce, resulting from the transient process of LC molecular reorientation, are eliminated when the cell is operated at high voltages. The appropriate display cell considering the driving voltage and response simultaneously is also developed at an optimum mixed concentration of 2 wt.%. Without overdrive, the turn-on response of this cell is comparable to that of the pure cell under overdrive. In order to conserve the power energy and enhance the image performance, a novel and reproducible alignment method for fabricating VA-based LC cells with a multi-pretilt structure is developed. A non-uniform vertical electric field is employed in the optimum IPS-VA LC/polymer cell during the photo-curing process, and two pretilt domains with the functional small pretilt angle (~ 1.6°) in the stabilized IPS-VA LC/polymer cells are achieved. As compared to the pure cell, this proposed cell shows 36%, 64%, and 76% enhancement in the optical-switch, gray-level rise time, and gray-level fall time responses, respectively. This research not only demonstrates a suitable monomer material and its concentration that, applied to IPS-VA LC cells, can benefit the molecular alignment and configuration, but also proposes a new method that effectively reduces the driving voltage and further boosts the device performance.3428654 bytesapplication/pdf論文公開時間: 2015/8/16論文使用權限: 同意有償授權(權利金給回饋本人)交鏈高分子網平面驅動垂直排列液晶分子結構錨定能響應時間Polymer networksvertically alignedin-plane switchingliquid crystalanchoringcross-linkingmolecular configurationpretilt angleresponsethesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/276074/1/ntu-104-D01943018-1.pdf