臺灣博碩士論文加值系統

　　本論文應用幾何與薄膜光學的方式，來提昇液晶顯示系統之光學特性。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，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。利用圓柱狀散射底面之光學圖案，開發等向性冷陰極管(CCFL)與非等向性發光二極體(LED)為光源之背光模組，在4吋CCFL與2.2吋LED背光模組設計中，經過數次的亮暗區域區域性圖案修改，均勻性分別提昇了37%與33%，驗證了區域性光學圖案的修改，成功的縮短背光模組開發所需的時程。背光模組之設計參數分析顯示，導光板上光學圖案的分佈設計，主導了整個背光模組的光學特性。
　　本論文亦應用光學薄膜之技術，來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 backlight unit and thin film coatings. 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. Optical performance of backlight unit with linear and/or an-isotropic light source(s) satisfying the uniformity and brightness can be achieved by the modification of the optical patterns. Design, analysis and verification of the 4-inch CCFL and 2.2-inch LED backlight units show that the luminance uniformity improves 37% and 33%, respectively. In the development of the backlight unit, the optical pattern design and modification dominate the characteristics of the unit.
　　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 the 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.

CONTENTS

Page
ABSTRACT i
CONTENTS iii
LIST OF TABLES vi
LIST OF FIGURES vii
NOMENCLATURE xii

Chapter 1 Introduction
1.1 Motivation 1
1.2 Literature Review 1
1.2.1 Geometric optics in backlight unit 1
1.2.2 Thin film optics in optical coating 3
1.3 Outline 5

Chapter 2 Integrated Design and Analysis of Backlight Unit
2.1 Introduction 9
2.2 CAD on Optical Pattern 10
2.3 Illumination on Optical Component 14
2.3.1 Analysis of LED light source 15
2.3.2 Analysis of white plastic plate 17
2.3.3 Analysis of prismatic microstructure 19
2.4 Conclusions 19

Chapter 3 Computer Aided Design of Optical Patterns in Light Guide Plate
3.1 Introduction 32
3.2 Optics in Backlight Unit 33
3.3 Light Guide with Isotropic CCFL 34
3.4 Light Guide with An-isotropic LED 37
3.4.1 Design of the light guide 38
3.4.2 Analysis of the light guide 39
3.4.3 Implementation of the backlight unit 41
3.5 Sensitivity Analysis 42
3.6 Conclusions 44

Chapter 4 Anti-reflection Coating by Thin Film Optics
4.1 Introduction 60
4.2 Thin Film Optics and Process 61
4.3 Multi-layer AR Coating Design 63
4.3.1 AR coating by V- and W-coating design 63
4.3.2 AR coating by optimization design 65
4.4 Multi-layer AR Coating 68
4.4.1 Thin film deposition 68
4.4.2 Characteristics of the AR coating 70
4.5 Anti-reflection Coating on Backlight Unit 72
4.6 Conclusions 73

Chapter 5 Electromagnetic Shielding Effectiveness of Multilayer Thin Films
5.1 Introduction 85
5.2 A Model of Electromagnetic Shielding 86
5.3 Analysis of Shielding Effectiveness 89
5.3.1 Optical thin film 89
5.3.2 Metallic thin film 91
5.4 Experimental Verification 93
5.5 Transflective Backlight Design by Thin Metal Films95
5.6 Conclusions 97

Chapter 6 Summary and Conclusion 109

References 112

Appendix A Illumination Improvement by Using the Integrated Software
A.1 Introduction 120
A.2 LGP Design Software 121
A.3 Illumination Improvement by the Software 124
A.4 Conclusion 128

Publication List 145

Vita 146

References
ASTM, “Standard Test Methods for Measuring Adhesion by Tape Test,” ASTM D3359-02, 2002.
ASTM, “Standard Test Method for Measuring the Electromagnetic Shielding Effectiveness of Planar Materials,” ASTM D4935-99, 1999.
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., 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.
Awadelkarim, O. O. and Wang, Y. Z., “The Impact of RCA Treatment of Glass Substrates on the Properties of Polycrystalline Silicon Thin Film Transistors,” Microelectronic Engineering, Vol. 45, pp. 299-310, 1999.
Barnejee, A. and DebRoy, T., “Optical Emission Investigation of the Plasma Enhanced Chemical Vapor Deposition of Silicon Oxide Films,” J. Vac. Sci. Technol. A, Vol. 10, No. 6, pp.3395-3400, 1992.
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.
Chatham, H., “Oxygen Diffusion Barrier Properties of Transparent Oxide Coatings on Polymeric Substrates,” Surface and Coatings Technology, Vol. 78, Issues 1-3, pp. 1-9, 1996.
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.
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.
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.
Donald, S. L. and Alimonda, A. S., “Chemistry of SiO2 Plasma Deposition,” J. Electrochem. Soc., Vol. 140, No. 5, pp. 1496-1502, 1993.
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.
Gordon, R., “Chemical Vapor Deposition of Coatings on Glass,” Journal of Non-Crystalline Solids, Vol. 218, pp. 81-91, 1997.
Gruniger, A. and Rohr, P. R. V., “Deposition of SiO2-like Diffusion Barriers on PET and Paper by PECVD,” Surface and Coatings Technology, Vol. 174, No. 175, pp. 1043-1047, 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.
Hick, R. and Halstead, W., “Flat Fluorescent Lamp Technology for LCD’s,” AIAA/IEEE Transactions on Digital Avionics Systems Conference, pp. 630-635, 1994.
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.
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.
Kim, B., Kim, D. W. and Han, S. S., “Refraction Properties of PECVD of Silicon Nitride Film,” Vacuum, Vol. 72, Issue 4, pp. 385-392, 2004.
Kim, N. Y., Son, Y. B., Oh, J. H., Hwangbo, C. K. and Park, M. C., “TiNx Layer as an Antireflection and Antistatic Coating for Display,” Surface and Coatings Technology, Vol. 128, No. 129, pp.156-160, 2000.
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.
Lin, L., Shia, T. K. and Chiu, C. J., “Fabrication and Characterization of IC-processed Brightness Enhancement Films,” IEEE International Conference on Solid-State Sensors and Actuators, pp. 1427-1430, 1997.
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.
Lua, Y. T. and Chia, S., “Fabrication of Light-shaping Diffusion Screens,” Optics Communications, Vol. 214, Issues 1-6, pp. 55-63, 2002.
Macleod, H. A., Thin Film Optical Filters, 3rd ed., Institute of Physics, London, 2001.
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.
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.
Oyama, H. and Shiramatsu, N., “Smaller and Bigger Displays,” Displays, Vol. 23, Issue 1-2, pp. 31-39, 2002.
Oyama, T. and Yamada, T., “Light-absorbing Wide-band Anti-reflection Coatings on PET Films by Sputtering,” Vacuum, Vol. 59, Issues 2-3, pp. 479-483, 2000.
Rodríguez, J. A., Domínguez, C., Muñoz, F. J. and Zine, N., “The Effect of Rapid Thermal Annealing on Properties of Plasma Enhanced CVD Silicon Oxide Films,” Thin Solid Films, Vol. 346, Issues 1-2, pp. 202-206, 1999.
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.
Schelknuoff, S. A., Electromagnetic Waves, D. Van Nostrand Company, Inc., 1943.
Schulz, U., Schallenberg, U. B. and Kaiser, N., ”Antireflection Coating Design for Plastic Optics,” Applied Optics, Vol. 41, No. 16, pp. 3107-3110, 2002.
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.
Southwell, W. H., “Gradient-index Antireflection Coatings,” Optics Letters, Vol. 8, No. 11, pp. 584-586, 1983.
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.
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.
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.
Van, D. J. F., “Computer Molding of LED Light Pipe System for Uniform Display Illumination,” Lighting Research Center, Rensselaer Polytechnic Institute, 2001.
White, D. R. J., A Handbook On Electromagnetic Shielding Materials and Performance, Interference Control Technologies, Inc., pp.1.1-1.40, pp. 2.1-2.10,1980.
Willey, R. R., Practical Design and Production of Optical Thin Films, Marcel Dekker, New York, 1996.
Winderbaum, S., Yun, F. and Reinhold, O., “Application of Plasma Enhanced Chemical Vapor Deposition Silicon Nitride as a Double Layer Antireflection Coating and Passivation Layer for Polysilicon Solar Cells,” J. Vac. Sci. Technol. A, Vol. 15, No. 3, pp. 1020-1025, 1997.
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.