應用幾何微結構與薄膜光學的方式，來提昇液晶顯示系統之光學特性。背光模組導光板之其幾何特徵影響其光學效能甚鉅，然而其互相關係的模擬研究仍相當缺乏，因此本文旨在探討其兩者間關係，以改善液晶顯示器的光學效果。此研究首先發展一套與光學分析軟體整合的微結構幾何設計軟體，並提出背光模組之電腦輔助設計與分析開發流程，利用三種代表性光學幾何設計：楔型化導光板、長溝槽微結構、半圓球狀微結構整合於光學分析軟體，有效改善背光模組開發的效率，成效驗證以非等向性發光二極體(LED)為光源之背光模組為例，在2.2吋LED背光模組設計中，經過規則性的幾何參數修改，透過三種結構優點結合有效提升光學穿透率，第一為將長溝槽於LED端，而達到81%亮度均勻性、73%透光率、2049.67cd/m2中心亮度，以用於低階低成本液晶顯示器；第二為將長溝槽微結構改放頂面，獲得88.76%亮度均勻性、75%透光率、2105.8cd/m2中心亮度；最後則結合了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。研究成果驗證幾何光學並提供一個明確的設計方式，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主導整個背光模組的光學特性，並有效改善其效能。
本文亦應用光學薄膜之技術，以增加顯示系統之光學穿透性。利用光學特徵矩陣與導納軌跡法，最佳化多層高穿透性抗反射光學薄膜，最佳化之結果為SiNx (N=1.90, 58nm)/ SiNx (N=2.10, 84nm)/ SiOx (N=1.46, 83nm)三層結構，所得到在可見光範圍內94.98%的高穿透性，並對製程誤差的敏感性較低。應用此高穿透性之光學結構於背光模組中，提昇了模組之光學特性。論文中也利用具電磁波防護效果(EMI)之導電性材料進行光學薄膜設計，提出多層光學薄膜電磁防護之計算模式，評估出透明導電材料氧化銦錫(ITO)的防護效果為12dB。將防護效果較高之Ag(100nm)/Ni(10nm)半透性金屬薄膜，應用於穿反式背光模組之設計中，在外界光源足夠之情況下，提昇了背光模組之光學特性，並在900 MHz頻率下的電磁防護效果為66.89 dB。

This dissertation aims at improving the optical performance of the display device by geometric microstructures and thin film coatings. It has been known that the optical microstructures and thin film qualities affect the optical performance of a light guide plate (LGP), but the relationship between them is still unknown as of today. This work attempts to explore the relationship so as to improve the optical performance of a display device in power efficiency and luminance uniformity. An integrated software is developed where a systematic interface between mechanical design and optical analysis of geometry optics is established. Current design practices of try-and-error and/or relying on expert-only can be significantly improved. This work presents three geometric microstructures: the wedge-shaped LGP, the groove-shaped microstructures and the half spherical patterns, to improve LCD design and development. The uniformity and brightness of optical performance of backlight unit with linear and/or an-isotropic light source(s) can be achieved by the combinations of the three microstructures. The first design model achieves 81% luminance uniformity, 73% power efficiency and 2049.67cd/m2 center luminance for LGP applications with high-level uniformity. The second design model achieves 88.76% luminance uniformity, 75% power efficiency and 2105.8cd/m2 center luminance, and the third design model provides 90.1% luminance uniformity, 81% power efficiency and 2274.29cd/m2 center luminance. This thesis improves the previous studies’ findings by providing more detailed examination of design process. The three design models with microstructures can improve the power efficiency and luminance uniformity.
The thin film optics is also applied in backlight unit to enhance the optical transmittance of display device. A model of multi-layer anti-reflection thin film coating is developed for analyzing optical performance and electromagnetic shielding effectiveness. Analysis is conducted by the admittance loci using the optical characteristic matrix to select the thin film materials and thickness. The results show that the three-layer dielectric coating of SiNx/SiNx/SiOx at 58/84/83 nm achieves an average transmittance of 94.14% in the visible region. The coating enhances the mean luminance of the 4-inch backlight unit design from 810 to 1019 cd/m2. The shielding effectiveness of the anti-reflection design embedded with the transparent conductive material is also analyzed. For multi-layer conductive optical design, the shielding effectiveness is about 12 dB, regardless of the layer sequence and the dielectric materials. Better shielding effectiveness is achieved by placing the thin metallic film with higher conductivity to permeability ratio closer to the substrate. The 2-layer polymer/Ag(100nm)/Ni(10nm) semi-transparent metallic structure can be applied to the 4-inch transflective backlight unit. The mean luminance improves from 1011 to 1130 cd/m2 at 2250 Lux external light. The shielding effectiveness is 66.89dB at the frequency of 900MHz.

Absalter, J., Karunakarna, S. and Subrahmanyam, A., “Properties of Indium Oxide Thin Films Prepared by Reactive Electron Beam Evaporation Technique for EMI Control,” Proc. Inter. Conf. on Electromagnetic Interference and Compatibility, pp. 366-371, 1999.
Anandan, M., “Progress of LED Backlights for LCDs,” Society for Information Display, Vol. 16, Issue 2, 2008.
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.
Chang, Y. Y. “On the Electromagnetic Shielding Effectiveness of Multilayer Metallic Thin Film on Plastic Substrates,” Master Thesis, Institute of Aeronautics and Astronautics, National Chung Kung University, 2003.
Chang, J. G., Fang, Y. B., Lu, J. M., Liu, C. W., Li, W. L. and Ju, S. P., “Fabrication and Optical Design of a Pyramid Microstructure for the Base of a Light Guide Used in Backlight Module,” J. Micro/Nanolith. MEMS and MOEMS, Vol. 9, Issue 4, 2010.
Cheng, Y. K., Lu, Y. H., Tien, C. H. and Shieh, H. P. “Design and Evaluation of Light Spread Function for Area-Adaptive LCD System,” Journal of Display Technology, Vol. 5, Issue 2, 2009.
Chien, C. H. and Chen, Z. P., “The Study of Integrated LED-backlight Plate fabricated by Micromachining Technique,” Microsystem Technology, 2008.
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.
Chou, L. S. and Lin, I H., “Design of White LED Light Source for Noble LCD Backlight Module,” Molecular Crystals and Liquid Crystals, Vol.495, pp. 432-448, 2008.
Cid, M., Stem, N., Brunetti, C., Beloto, A. F. and Ramos, C. A. S., “Improvements in Anti-reflection Coatings for High-efficiency Silicon Solar Cells,” Surface and Coatings Technology, Vol. 106, pp. 117-120, 1998.
Dahoudi, N. A., Bisht, H., Gobbert, C., Krajewski, T. and Aegerter, M. A., “Transparent Conducting, Anti-static and Anti-glare Coatings on Plastic Substrates,” Thin Solid Films, Vol. 392, Issue 2, pp. 299-304, 2001.
Dobrowolski, J. A., Poitras, D., Ma, P., Vakil, H. and Acree, M., “Toward Perfect Antireflection Coatings: Numerical Investigation,” Applied Optics, Vol. 41, No. 16, pp. 3075-3083, 2002.
Dobrowolski, J. A. and Sullivan, B. T., “Universal Antireflection Coatings for Substrates for the Visible Spectrum Region,” Applied Optics, Vol. 35, No. 25, pp. 4993-4997, 1996.
Engelsen, D. D., Lim, S. and Käläntär, K., “Special Section on Display Backlighting ,” Journal of the Society for Information Display, Vol. 16, Issue 2, pp. 285-286, 2008.
Feng, D., Yan, Y., Yang, X., Jin G. and Fan S., “Novel Integrated Light-Guide Plates for Liquid Crystal Display Backlight,” Journal of Optics A: Pure and Applied Optics, Vol. 7, Issue 3, 2005.
Folkerts, W., “LED Backlighting Concepts with High Flux LEDs,” SID Digest, pp. 1226-1229, 2004.
Fukuda, S., Kawamoto, S. and Gotoh, Y., “Degradation of Ag and Ag-alloy Mirrors Sputtered on Poly (ethyleneterephthalate) Substrates under Visible Light Irradiation,” Thin Solid Films, Vol. 442, Issues 1-2, pp. 117-120, 2003.
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.
Hiang, J. L., Yau, B. S., Chen, C. Y., Lo, W. T. and Lii, D. F., “The Electromagnetic Shielding Effectiveness of Indium Tin Oxide Films,” Ceramics International, Vol. 27, Issue 3, pp. 363-365, 2001.
Hong, Y. Y., Wang B. P., ZHU Z. J. and Zheng S., “Research on New Reflector to Improve Brightness Uniformity of LED Backlights,” Optoelectronic Technology, 2008.
Huang, C., Jiang., Y. S., Shen Y. and Wu Y. J., “Design of Scattering Netted Dots on Light Guide Plate of Edge-lighting LED Backlight,” Journal of Applied Optics, 2008.
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.
Ishikawa, H., Honjo, Y. and Watanabe, K., “Three-layer Broad-band Antireflective Coating on Web,” Thin Solid Films, Vol. 351, Issues 1-2, pp. 212-215, 1999.
Jagt, H. J. B., Cornelissen, H. J., Broer, D. J. and Bastiaansen, C. W. M., “Linearly Polarized Light-emitting Backlight,” Journal of the SID, Vol. 10, No. 1, pp. 107-112, 2002.
Jooa B. Y. and Shin D. H., “Design Guidance of Backlight Optic for Improvement of the Brightness in the Conventional Edge-lit LCD Backlight,” Elsevier on Displays, Vol. 31, Issue 2, pp. 87-92, 2010.
Ju, Y. H., Park J. H., Lee, J. H., Lee, J. Y., Nahm, K. B., Ko, J. H. and Kim, J. H., “Study on the Simulation Model for the Optimization of Optical Structures of Edge-lit Backlight,” Journal of the Optical Society of Korea, Vol. 12, No. 1, pp. 25-30, 2008.
Käläntär, K., “Modified Functional Light-Guide Plate for Backlighting Transmissive LCDs,” Journal of the Society for Information Display, Vol. 11, Issues 4, pp. 641-645, 2003.
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.
Klein, C. A., “Microwave Shielding Effectiveness of EC-coated Dielectric Slab,” Transactions on Microwave Theory and Techniques, Vol. 38, No 3, pp. 321-324, 1990.
Koyama Y., “Ray-Tracing Simulation in LCD Development,” Sharp Techanical Journal, No. 3, 2001.
Lee, G., Choi, D. H., Jeong, J. H. and Yoon S. J., “Design Optimization for Optical Patterns in a Light-guide Panel to Improve Illuminance and Uniformity of the Liquid-crystal Display,” Optical Engineering, Vol. 48, Issue 2, 2009.
Li, C. J., Fang, Y. C., and Cheng, M. C., “Study of Optimization of an LCD Light Guide Plate with Neural Network and Genetic Algorithm,” Optics Express, Vol. 17, Issue 12, pp. 10177-10188, 2009.
Li, C. J., Fang, Y. C., Chu, W. T. and Cheng, M. C., “Design of a Prism Light-guide Plate for an LCD Backlight Module,” Journal of the Society for Information Display, Vol. 16, Issue 4, pp. 545-550, 2008.
Lin, C. F., Fang, Y. B. and Yang P. H., “Optical Film with Microstructures Array for Slim-type Backlight Applications,” International Journal for Light and Electron Optics, Vol. 122, Issues 13, pp. 1169-1173, 2011.
Lobl, H. P., Huppertz, M. and Mregel, D., “ITO Films for Antireflective and Antistatic Tube Coatings Prepared by DC Magnetron Sputtering,” Surface and Coatings Technology, Vol. 82, pp. 90-98, 1996.
Martinet, C., Paillard, V., Gagnaire, A. and Joseph, J., “Deposition of SiO2 and TiO2 Thin Films by Plasma Enhanced Chemical Vapor Deposition for Antireflection Coating,” J. Non-Crystalline Solids, Vol. 216, pp. 77-82, 1997.
Mentley, D. E., “State of Flat-Panel Display Technology and Future Trends,” Proceedings of the IEEE, Vol. 90, No. 4, 2002.
Min, J. H., Choi, H. Y., Lee, M. G., Choi, J. S., Kim, J. H. and Lee S. M., “Holographic Backlight Unit for Mobile LCD Devices,” Journal of the Society for Information Display, Vol. 11, Issues 4, pp. 653-657, 2003.
Nikolajeff, F., Lofving, B., Johansson, M., Bengtsson, J., Hard, S. and Heine, C., “Fabrication and Simulation of Diffractive Optical Elements with Superimposed Antireflection Subwavelength Gratings,” Applied Optics, Vol. 39, No. 26, pp. 4842-4846, 2000.
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.
Onac, G. E., Vogels, I., Bartula, M, Hoevenaars, M. and Louwsma, H. K., “Scanning Backlight for Motion-blur Reduction on Mobile Displays,” Journal of the Society for Information Display, Vol. 16, Issue 2, pp. 337-341, 2008.
Pan J. W. and Fan. C. W., “High Luminance Hybrid Light Guide Plate for Backlight Module Application,” Optics Express, Vol. 19, Issue 21, pp. 20079-20087, 2011.
Poxson, D. J., Kuo, M. L., Mont, F. W., Kim, Y. S., Yan, X., Welser, R. E., Sood, A. K., Cho, J., Lin, S. Y. and Schubert, E. F., “High-Performance Antireflection Coatings Utilizing Nanoporous Layer,” MRS Bullentin, Vol. 36, 2011.
Sarto, M. S. and D’Amore, M., “Nanotechnology of Transparent Metals for Radio Frequency Electromagnetic Shielding,” IEEE Transactions on Electromagnetic Compatibility, Vol. 45, No. 4, pp. 586-594, 2003.
Schulz, R. B., Plantz, V. C. and Brush, D. R., “Shielding Theory and Practice,” IEEE Transactions on Electromagnetic Compatibility, Vol. 30, No. 3, pp. 187-201, 1988.
Schulz, U., Schallenberg, U. B. and Kaiser, N., ”Antireflection Coating Design for Plastic Optics,” Applied Optics, Vol. 41, No. 16, pp. 3107-3110, 2002.
Southwell, W. H., “Gradient-index Antireflection Coatings,” Optics Letters, Vol. 8, No. 11, pp. 584-586, 1983.
Sun, Z., Chang, J., Zhao, N. Jin, W. and Wang, Y., “Research of Diffusing Plates for LCD backlights,” Elsevier on Optic, Vol. 121, pp. 760-764, 2010.
Suzuki, M., Mamiya, J. and Tanase, H., “Improvement of Backlighting Method by Means of Light Pipe Polarizer,” Proc. EuroDisplay, pp. 229-232, 1996.
Suzuki, M., “Two Approach to the Luminance Enhancement of Backlighting Units for LCDs,” Journal of the SID, Vol. 7, No. 3, pp. 157-161, 1999.
Tanase, H., Mamiya, J. and Suzuki, M., “A New Design of Coupled Prismatic Polarizer Light Pipe by Altering the Prism Apex Angle: A Theoretical Treatment,” SID Intl. Symp. Digest Tech. Papers, pp. 61-64, 1997.
Tanase, H., Mamiya, J. and Suzuki, M., “A New Backlighting System with a Polarizer Light Pipe for Enhanced Light Output from LCDs,” SID Intl. Symp. Digest Tech. Papers, pp. 365-368, 1997.
Teng, T. C. and K. F. “Highly Precise Optical Model for Simulating Light Guide Plate Using LED Light Source,” Optics Express, Vol. 18, Issue 21, pp. 22208-22214, 2010.
Tien, C. H., Hung, C. H. and Yu T. H. “Microlens Arrays by Direct-Writing Inkjet Print for LCD Backlighting Applications,” Journal of Display Technology, Vol. 5, Issues 5, pp. 147-151, 2009.
Van, D. J. F., “Computer Molding of LED Light Pipe System for Uniform Display Illumination,” Lighting Research Center, Rensselaer Polytechnic Institute, 2001.
Willey, R. R., “Practical Design and Production of Optical Thin Films,” Marcel Dekker, New York, 1996.
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.
Yang, J. C., “Development of Geometric and Thin Film Optics in LCD Module for Optical Enhancement,” Doctor of Philosophy Thesis, Institute of Aeronautics and Astronautics, National Chung Kung University, 2005.
Zhang, J., Gu, W., Chen, Z., Yu, J., Zhong, Y., Zhou, D. and Cai, C., “Research and Analysis of Edge Backlighting Light Guide Panel for Handset,” Proc. of SPIE, Vol. 7849, 2010.
Zhu, X., Chen Q., Jiang., F. and Wu, H., “Novel High-brightness Backlight Module for Autostereoscopic Liquid Crystal Display,” Optical Engineering, Vol. 50, Issue 5, 2011.