本文應用導光板上幾何微結構的設計，來提昇液晶顯示系統之光學特性。研究者對於背光模組中之導光板的設計常指出，針對微結構的設計往往會影響所分析導光板的光學效能。然而導光板上微結構的設計與光學效能影響之關係的模擬研究仍相當缺乏，因此本研究旨在探討其兩者間關係，以改善液晶顯示器的光學效果。研究方法是首先發展在電腦輔助設計平台上三種代表性微結構的幾何設計程式並且光學分析軟體整合，有效的改善目前背光模組開發的低效率與需倚賴專家設計之限制，這三種設計分別是楔型化導光板、長溝槽微結構、半圓球狀微結構。研究結果顯示楔型化導光板與導光板上方長溝槽微結構對於透光率有相當程度影響，而導光板光源側長溝槽微結構與導光板底面不同密度分佈半圓球狀微結構則深深影響亮度均勻性與透光率。所以必須結合這幾種微結構的優點以獲得一塊較佳的導光板。總結而言，此研究希望對於這三種設計的關係可以藉此進一步了解。在非等向性發光二極體(LED)為光源與2.2吋LED背光模組設計中，經過多次規則性微結構設計，並獲得三種導光板其有較佳光學性能，第一種是一般常見導光板設計擁有81%亮度均勻性、73%透光率、2049.67cd/m2中心亮度，此種光學性能足以用於低階液晶顯示器，第二種是將長溝槽微結構改放導光板頂面此種設計獲得88.76%亮度均勻性、75%透光率、2105.8cd/m2中心亮度。最後一種則結合了導光板上方與燈源面長溝槽微結構配合楔型化導光板與不同密度分佈半圓球狀微結構達到90.1%亮度均勻性、81%透光率、2274.29cd/m2中心亮度。驗證了以前對於光學圖案的研究，並提供一個較明確的設計方式，成功的縮短背光模組開發所需的時程。總結對於三種微結構之設計參數分析顯示，其主導了整個背光模組的光學特性，並有效改善其效能。

Researches of the design of light guide plate (LGP) have often suggested that the microstructures would likely affect the optical performance of LGP, but their relation remains unknown as of today. This thesis attempts to explore the relation, so as to improve the optical performance of a display device in power efficiency and luminance uniformity. Current design practices of try-and-error and relying on expert-only can be significantly improved. Results of this study show that the groove-shaped microstructures on the top surface of a wedge-shaped LGP apparently achieve better power efficiency, and the groove-shaped microstructures on the LED side of LGP and the spherical patterns on the bottom surface of the LGP also obtain better luminance uniformity and power efficiency. Combination of three designs is proposed in this thesis. The first model is provided with 81% luminance uniformity, 73% power efficiency and 2049.67cd/m2 center luminance, due to the high quality of luminance uniformity. This LGP can be used for the backlight unit that requires high-level uniformity. The second model applied to general backlight unit provides with 88.76% luminance uniformity, 75% power efficiency and 2105.8cd/m2 center luminance. The third model provides with 90.1% luminance uniformity, 81% power efficiency and 2274.29cd/m2 center luminance. This thesis improves the previous studies’ findings by providing a much more detailed examination of design processes. The three models with simple design of microstructures can improve the power efficiency and luminance uniformity.

[1] 張自恭, 林奇鋒, 方育斌, “背光模組光學設計”, 光連第49 期, 2004/1.
[2] 方育斌, “LCD背光模組之光學最佳化設計”, 國立成功大學工業工程與管理學系碩士論文, 2004.
[3] 蘇紹安, “非印刷式背光模組光學模擬分析”, 中華大學機械工程學系碩士論文, 2000.
[4] 蔣宗樹, “導光板導光設計之研究”, 中原大學機械工程學系碩士論文，2003.
[5] 張耀祖, “使用發光二極體為光源的背光板設計”, 中華大學電機工程學系碩士論文, 2004.
[6] 楊仁傑, “應用幾何與薄膜光學以提昇液晶顯示系統光效率之研究”, 國立成功大學航空太空工程學系博士論文, 2005.
[7] Broer, D. J., Seppen, C. J. E. and Boots, H. M., “Illumination System for a Flat-panel Picture Display Device,” U. S. Patent No. 5729311, 1998.
[8] Kalantar, K., “Modulation of Viewing Angle on an LCD Surface through Backlight Optics,” Journal of the SID, Vol. 11, No. 4, pp. 647-652, 2003
[9] Choi, J., Hahn, K. S., Seo, H. and Kim, S. C., “Design, Analysis, and Optimization of LCD Backlight Unit Using Ray Tracing Simulation,” Inter. Conf. on Computational Science and Its Applications, pp. 837-846, 2004.
[10] Koyama Y., “Ray-tracing Simulation in LCD Development,” Sharp Techanical Journal, No. 3, 2001.
[11] Ide, T., Numata, H., Taira, Y., Mizuta, H., Suzuki, M., Noguchi, M. and Katsu, Y., “A Novel Dot-pattern Generation to Improve Luminance Uniformity of LCD Backlight,” Journal of the SID, Vol. 11, No. 4, pp. 659-665, 2003.
[12] Folkerts, W., “LED Backlighting Concepts with High Flux LEDs,” SID Digest, pp. 1226-1229, 2004.
[13] Harbers, G., Timmers, W. and Sillevis-Smitt, W., “LED Backlighting for LCD HDTV,” Journal of the SID, Vol. 10, No. 4, pp. 347-350, 2002.
[14] Yamada, F., Nakamura, H., Sakaguchi, Y. and Taira, Y., “Sequential-color LCD Based on OCB with an LED Backlight,” Journal of the SID, Vol. 10, No. 1, pp. 81-85, 2002.
[15] 陳興華, ”LCD 背光模組導光板成型模具精密蝕刻加工技術”, 工業材料雜誌207期, 2004/3.
[16] 曾文政, “液晶顯示器背光板用導光板V-CUT加工之探討”, 義守大學材料科學與工程學系碩士論文, 2004.
[17] 葉秋鈴, “六標準差應用於導光板印刷製程之最佳化研究”, 元智大學工業工程與管理學系碩士論文, 2004.
[18] Oyama, H. and Shiramatsu, N., “Smaller and Bigger Displays,” Displays, Vol. 23, Issue 1-2, pp. 31-39, 2002.
[19] Hick, R. and Halstead, W., “Flat Fluorescent Lamp Technology for LCD’s,” AIAA/IEEE Transactions on Digital Avionics Systems Conference, pp. 630-635, 1994.
[20] Anandan, M., Ketchum, D., Etlinger, H., Kirker, R. and Carr, W., “Design of a Multi-channel True Flat Fluorescent Lamp for Avionic AM-LCD Backlighting,” IEEE Transactions on Electron Devices, Vol. 41, No. 4, pp. 504-510, 1994.
[21] Lua, Y. T. and Chia, S., “Fabrication of Light-shaping Diffusion Screens,” Optics Communications, Vol. 214, Issues 1-6, pp. 55-63, 2002.
[22] Tagaya, A., Nagai, M., Koike, Y. and Yokoyama, K., “Thin Lquid-crystal Display Backlight System with Highly Scattering Optical Transmission Polymers,” Applied Optics, Vol. 40, No. 34, pp. 6274-6280, 2001.
[23] Okumura, T., Tagaya, A. and Koike, Y., “Highly-efficient Backlight for Liquid Crystal Display Having No Optical Films,” Applied Physics Letters, Vol. 83, No.13, pp. 2515-2517, 2003.