臺灣博碩士論文加值系統

本論文旨在探討層化高分子/液晶薄膜的電壓保持率與殘餘直流電壓特性；即利用本實驗室所開發之自動化量測系統，測量液晶或高分子標準樣品與不同混合比例之非對稱層化高分子/液晶樣品的電壓保持率與殘壓值，以釐清層化樣品中各層材料的分別貢獻。
研究結果顯示：一、層化高分子/液晶複合薄膜的電壓保持率由高分子的比例所主導—當高分子含量愈高時，元件整體之電阻值上升，使電壓保持率愈高；二、層化高分子/液晶複合薄膜的殘餘直流電壓與高分子結構密不可分—高分子前驅物的含量會影響其受紫外光照射下聚合物的固化過程，當其比例愈高時，固化愈穩定且表面愈平整，這會抑制高分子層介面吸附離子雜質的能力，使殘餘直流電壓值變低；三、層化高分子/液晶元件的電流對電壓曲線圖與典型之純液晶元件大異其趣；高分子與液晶二者複合後的電流對電壓特性趨勢仍由高分子材料層所主導。

Voltage holding ratio (VHR) and residual direct current (RDC) of stratified polymerliquid-crystal films are investigated in this thesis. The auto-measurement system developed in this laboratory is used to monitor the VHR and RDC in standard cells of either liquid crystal or polymer alone and in asymmetric ones of polymerliquid-crystal layer hybrid with various polymer contents, clarifying the contributions of the liquid-crystal and polymer layers separately to the VHR and RDC of the stratified films.
The thesis demonstrates: (1) the VHR of stratified polymerliquid- crystal films is dominated by the polymer concentration—the more the polymer content is, the higher the bulk resistance becomes, leading to the higher VHR; (2) the RDC of stratified samples depends on the polymeric structure—as the precursor concentration increases, the solidification process mitigates during photopolymerization and the polymeric surface becomes smoother, resulting in suppressed ion-adsorptive capability on the interface and, in turn, reducing the RDC; (3) the currentvoltage behavior of a stratified cell, again dictated by the polymer layer, is distinctive from that of a typical liquid-crystal cell.

中文摘要…………………………………………………………..I
英文摘要…………………………………………………………..II
致謝………………………………………………………………..III
目錄………………………………………………………………..IV
圖索引……………………………………………………………..VII
表索引……………………………………………………………..X
第一章 緒論……………………………………………………..1
1.1 離子的產生及其影響……………...........................4
1.2 高分子概述…………………………………………6
1.2.1 高分子的生產步驟、結構與分類………….7
1.2.2 用於本論文研究中之高分子……………….11
1.3 高分子電性…………………………………………13
1.4 本論文研究內容……………………………………15
第二章 研究背景………………………………………………..17
2.1 電壓保持率與殘餘直流電壓的研究進展…………17
2.2 電壓保持率與殘餘直流電壓的量測原理…………20
2.2.1 電壓保持率量測原理…………………….....20
2.2.2 殘餘直流電壓量測原理…………………….22
2.3 電流對電壓曲線……………………………………25
第三章 樣品製作與實驗裝置………………………………….. 27
3.1 材料……………………………..............................27
3.2 樣品製備…………………………….......................28
3.2.1 液晶空盒製作……………………………….28
3.2.2層化高分子/液晶樣品製備………...............29
3.3實驗裝置與量測…………………………………….31
3.3.1 電壓保持率之量測………………………….31
3.3.2 殘餘直流電壓之量測……………………….32
3.3.3 整合型量測系統……………………….……33
3.3.4 電流與電壓的量測………………................34
第四章 實驗結果與討論……………………….......................... 35
4.1電壓保持率的量測………………………………….36
4.1.1 不同厚度的液晶層………………………….38
4.1.2 不同混合比例……………………………….39
4.1.3 紫外線曝光時間…………………………….42
4.1.4 紫外光對液晶電壓保持率的響…………….43
4.2 餘直流電壓的量測…………………………………44
4.2.1 不同液晶層厚度…………………………….45
4.2.2 不同混合比例………………………………47
4.2.3 不同曝光時間………………………………51
4.3 電流與電壓的量測曲線圖………………………...52
第五章 結論與未來展望………………………………………55
參考文獻…………………………………………………………58


圖索引
圖1.1 層化高分子/液晶結構。.……………………………..77
圖1.2 (a) 直線排列型態（高密度聚乙烯，HDPE）………..77
(b) 樹枝狀排列型態（低密度聚乙烯，LDPE）…......77
(c) 交聯排列型態（酚甲醛，PF）……………………78
圖1.3 (a) 耐隆6的分子結構（nylon 6）…………………78
(b) 聚亞醯胺的分子結構（polyimide，PI）…………78
(c) 高分子前驅物NOA65的四種聚合物分子結構79
圖2.1 液晶層等效電路模型。………………………………80
圖2.2 非理想電容器放電曲線。……………………………80
圖2.3 電壓保持率量測圖。…………………………………81
圖2.4 直流殘壓形成圖。……………………………………81
圖2.5 直流殘壓量測概念圖。………………………………82
圖3.1 電壓保持率量測基本電路架構。……………………82
圖3.2 電壓保持率量測完整實驗裝置圖。…………………83
圖3.3 直流殘壓特性量測基本電路架構。…………………83
圖3.4 殘餘直流電壓量測實驗裝置圖。……………………84
圖3.5 VRMS-01（VHR & RDC Measurement System-01）
原型。…………………………………………………84
圖3.6 電壓保持率程式操作面板。…………………………85
圖3.7 直流殘壓特性量測介面。……………………………85
圖3.8 電流與電壓曲線量測實驗裝置圖。…………………86
圖3.9 電流與電壓曲線量測概念流程圖。…………………86
圖3.10 實驗量測流程圖…………………………………….87
圖4.1 殘餘直流電壓VmRDC與液晶層厚度的關係圖。……88
圖4.2 殘餘直流電壓VsRDC與液晶層厚度的關係圖。……88
圖4.3 對稱結構中產生殘餘直流電壓的機制。……………89
圖4.4 樣品LC 40-60之時變殘餘直流電壓。………………90
圖4.5 樣品LC 50-50之殘餘直流電壓值。…………………90
圖4.6 樣品LC 60-40之殘餘直流電壓值。…………………91
圖4.7 樣品LC 60-40之光穿透度遲滯曲線圖
（0→30→0 V）。……………………………………...92
圖4.8 樣品LC 50-50之光穿透度遲滯曲線圖
（0→30→0 V）。……………………………………93
圖4.9 樣品LC 30-70之殘餘直流電壓值。為上基板（高
分子）接負極。……………………………………...94
圖4.10 樣品LC 80-20之殘餘直流電壓值。為上基板（高
分子）接負極。………………………………………94
圖4.11 不同混和比例樣品之殘餘直流電壓值。……………95
圖4.12 不同混和比例樣品之SEM表面形貌，由上而下依
序為高分子百分比分別為25%、50%、75%。………96
圖4.13 樣品LC 100-0之殘餘直流電壓值。…………………97
圖4.14 樣品LC 0-100之殘餘直流電壓值。…………………97
圖4.15 不同紫外光曝光時間的樣品LC 50-50之殘餘直流
電壓值。由上而下依序為曝光30分鐘、曝光60
分鐘、曝光90分鐘、曝光120分鐘，皆為上基板
接負極。……………………………………………..98
圖4.16 厚度為4.2 μm之純液晶E7的I−V量測曲線圖。……99
圖4.17 厚度為4.2 μm之純液晶CYLC 01的I−V量測曲線
圖。…………………………………………………..99
圖4.18 不同混合比例樣品之I−V量測曲線圖。……………100


表索引
表一 液晶E7之物理特性……………………………………….63
表二 高分子NOA65之特性…………………………………...64
表三 不同標準液晶盒厚度下純液晶E7的電壓保持率……….65
表四 不同厚度下純液晶E7的電壓保持率………..………….66
表五 不同E7/NOA65混合比例的電壓保持率……………….67
表六 液晶與高分子的電阻率……………………….................68
表七 控制液晶與高分子層厚度下的電壓保持率…………….69
表八 不同紫外曝光時間的電壓保持率……………………….70
表九 有無紫外曝光下純液晶E7的電壓保持率……………..71
表十 盒厚對液晶E7的殘餘直流電壓的影響……..………….72
表十一 不同E7/NOA65混合比例的殘餘直流電壓..................73
表十二 控制液晶與高分子層厚度下的殘餘直流電壓………..74
表十三 不同紫外曝光時間的殘餘直流電壓………….……….75
表十四 純高分子在不同紫外曝光時間下的電阻值…………..76

[1]V. Vorflusev and S. Kumar, “Phase-separated composite films for liquid crystal displays,” Science 283(19), 1903–1905 (1999).
[2]Q. Wang and S. Kumar, “Submillisecond switching of nematic liquid crystal in cells fabricated by anisotropic phase-separation of liquid crystal and polymer mixture,” Applied Physics Letters 86(7), 071119-1–3 (2005).
[3]Q. Wang, R. Guo, M. R. Daj, S-W. Kang, and S. Kumar, “Flexible plastic display fabricated using phase-separated composite films of liquid crystals,” Japanese Journal of Applied Physics 46(1), 299–303 (2007).
[4]R. Penterman, S. I. Klink, H. de Koning, G. Nisato, and D. J. Broer, “Single-substrate liquid crystal displays by photo-enforced stratification,” Nature 417(2), 55–58 (2002).
[5]Y.-H. Lin, H. Ren, S. Gauza, Y.-H. Wu, Y. Zhao, J. Fang, and S.-T. Wu,,“IPS-LCD using a glass substrate and an anisotropic polymer film,” Journal of Display Technology 2(1), 21–25 (2006).
[6]H. Ren, S.-T. Wu, and Y.-H. Lin, “Single glass substrate liquid crystal device using electric field-enforced phase separation and photoinduced polymerization,” Applied Physics Letters 90(19), 191105-1–3 (2007).
[7]H. Ren, S.-T. Wu, and Y.-H. Lin, “In situ observation of fringing-field-induced phase separation in a liquid-crystal–
monomer mixture,” Physical Review Letters 100(11), 117801-1–4 (2008).
[8]H.-H. Yu, S.-J. Hwang, R.-L. Chen, and C.-Y. Yang, “Study of the purifying affects of thermal annealing for polymer-wall liquid crystal cells,” Liquid Crystals 35(12), 1339–1343 (2008).
[9]K.-S. Bae, Y. Choi, H.-R. Kim, and J.-H. Kim, “Fabrication of single substrate flexible twisted nematic LC cell using a photo-polymer cover film,” Molecular Crystals and Liquid Crystals 498(12), 110–117 (2009).
[10]巫崇印，《層化高分子/液晶複合薄膜的直流電場效應》，碩士論文，中原大學應用物理研究所，民97年7月。
[11]松本正一、角田市良，《液晶的基礎與應用》，劉瑞祥譯，國立編譯館，台北市，民85年。[ISBN: 957-00-7449-3
[12]S. Murakami and H. Naito “Charge injection and generation in nematic liquid crystal cells,” Japanese Journal of Applied Physics 36(2), 773–776 (1997).
[13]S. Murakami and H. Naito “Electrode and interface polarization in nematic liquid crystal cells,” Japanese Journal of Applied Physics 36(4A), 2222–2225 (1997).
[14]N. J. Kim, J. Kim, J. Jung, Y. S. Choi, and S. B. Kwon, “Influence of contamination on nematic liquid crystal pretilt angle,” Society for Information Display International Symposium Digest of Technical Papers 77(1), 77–80 (1997).
[15]劉士榮，《高分子流變學》，滄海書局，台北市，民94年。
[ISBN: 986-7287-06-1]
[16]何經、呂佳燕、黃勝明，《高分子材料》，復文書局，台南市，民89年。
[17]馬德柱、何平笙、徐種德、周漪琴，《高聚物的結構與性能》，科學出版社，北京，民93年。
[18]王國梅、萬發荣，《材料物理》，武漢理工大學出版社，武漢，民93年。
[19]J. Mort and G. Pfister, Electronic Properties of Polymers (Wiley, New York, 1982). [ISBN: 13 978-0-521-55219-6]
[20]I.-K. Huh and Y.-B. Kim, “Fluoro-isothiocyanated liquid crystal materials with high dielectric anisotropy and voltage holding ratio,” Japanese Journal of Applied Physics 41(11A), 6466–6470 (2002).
[21]M. Nishikawa, T. Suganuma, Y. Tsuda, N. Bessho, Y. Iimura, and S. Kobayashi, “Properties of voltage holding ratio of liquid crystal cells using organic-solvent-soluble polyimide alignment films,” Japanese Journal of Applied Physics 33(8A), 1113–1116 (1994).
[22]H. Seiberle and M. Schadt, “LC-conductivity and cell parameters; Their influence on twisted nematic and supertwisted nematic liquid crystal displays,” Molecular Crystals and Liquid Crystals 239(1), 229–244 (1994).
[23]C. Colpaert, B. Maximus, and A. de Meyer, “Adequate measuring techniques for ions in liquid crystal layers,” Liquid Crystals 21(1), 133–142 (1996).
[24]N. Sasaki, “Simulation of the voltage holding ratio in liquid crystal displays with a constant charge model,” Japanese Journal of Applied Physics 37(11), 6065–6070 (1998).
[25]T. Nakanishi, T. Takahashi, H. Mada, and S. Saito, “Transient behavior of voltage holding ratio in nematic liquid crystal cells,” Japanese Journal of Applied Physics 41(6A), 3752–3757 (2002).
[26]M. Oh-e, Y. Umeda, M. Ohta, S. Aratani, and K. Kondo, “Unusual voltage-holding ratio characteristics using in-plane switching on nematic liquid crystals,” Japanese Journal of Applied Physics 36(8A), 1025–1028 (1997).
[27]Y.-J. Jeon, J.-Y. Hwang, and D.-S. Seo, “Voltage holding ratio and residual DC property of the IPS-LCD on rubbed polymer layers by voltage-transmittance hysteresis method,” Molecular Crystals and Liquid Crystals 410(369), 897–908 (2004).
[28]Y. Nakazono, T. Takagi, A. Sawada, and S. Naemura, “Evaluation of residual DC of LC cell,” Proceedings of the 5th Asian Symposium on Information Display 219–222 (1999).
[29]M. Mizusaki, T. Miyashita, T. Uchida, Y. Yamada, Y. Ishii, and S. Mizushima, “Generation mechanism of residual direct current voltage in a liquid crystal display and its evaluation parameters related to liquid crystal and alignment layer materials,” Journal of Applied Physics 102(1), 014904-1–6 (2007).
[30]M. Inoue, K. Takatoh, and S. Kobayashi, “Recent measurement of liquid crystal material characteristics,” Proceedings of the 13th International Display Workshops 647–650 (2006).
[31]C. K. Alexander and M. N. O. Sadiku, Fundamentals of Electric Circuits (McGraw-Hill, New York, 2007). [ISBN: 978-0-07-
110582-8]
[32]H.-C. Moon, Y.-H. Bae, J.-Y. Hwang, K.-W. Kim, and D.-S. Seo, “Residual DC characteristic on twisted nematic liquid crystal display on the polyimide surface by the thermal stress,” Molecular Crystals and Liquid Crystals 443(1), 161–166 (2005).
[33]A. R. M. Verschueren, P. Kohsiek, M. T. Johnson, and R. van Asselt, “DC current measurements on liquid crystal cells as indicative tool for image retention phenomena,” SID, 55–58 (2000).
[34]S. Vermael, K. Neyts, and H. Pauwels, “Long-term ion transport in nematic liquid crystal displays,” Japanese Journal of Applied Physics 40(5A), 3272–3276 (2001).
[35]A. Abderrahmen, F. F. Romdhane, H. B. Ouada, and A. Gharbi, “Indium–tin oxide surface treatments effects on the performance of liquid crystal devices,” Materials Science and Engineering: C 26(2-3), 538–541 (2006).
[36]A. R. M. Verschueren, R. A. H. Niessen, P. H. L. Notten, W. Oepts, and E. M. L. Alexander-Moonen, “Experiment and modeling of conduction and charge accumulation in liquid crystal cells,” IEEE Transactions on Dielectrics and Electrical Insulation 10(6), 963-969 (2003).
[37]M. Oh-E, and K. Kondo, “Advantageous voltage-holding ratio characteristics induced by in-plane electric fields, and the optimization concept of liquid crystals for an in-plane switching electro-optical effect,” Liquid Crystals 25(6), 699–709 (1998).
[38]M. Jiao, Z. Ge, Q. Song, and S.-T. Wu, “Alignment layer effects on thin liquid crystal cells,” Applied Physics Letters 92(6), 061102-1–3 (2008).
[39]H. Naito, K. Yoshida, M. Okuda, and A. Sugimura, “Transient current study of ultraviolet-light-soaked states in n-pentyl-p-n-
cyanobiphenyl,” Japanese Journal of Applied Physics 33(10), 5890–5891 (1994).
[40]K.-H. Yang, K. Tajima, A. Takenaka, and H. Takano, “Charge trapping properties of UV-exposed polyimide films for the alignment of liquid crystals,” Japanese Journal of Applied Physics 35(5A), 561–563 (1996).