臺灣博碩士論文加值系統

根據先前實驗室團隊的研究，超薄玻璃上之雷射熱源會使其產生高溫，表面也許會伴隨著相變化的產生。使用COMSOL模擬軟體做為模擬溫度分布的工具，在加熱玻璃過程中，有考慮相變化，因此模擬出的溫度分佈會較趨近於真實情況。
這篇論文的目的在於使用一個簡單的物理模型去探討雷射加熱玻璃的影響性，結合先前的研究使雷射加熱模擬更加接近真實值，接著將這套模擬方法應用於雷射切割超薄玻璃的分析上。
本研究所使用的材料為Al2O3，經由模擬結果和實驗結果比較過後，發現可變參數的重要性，尤其以熱傳導係數及相變化熱最為重要，在模擬中不可忽略。材料表面對雷射的反射率也是極重要的一環，表面光滑時反射率為0.25，雖然無法精確地了解表面粗糙對於反射率的影響，仍然可以推估出在融化時的反射率約為0.0744。最後得到一個適合的模擬方法來得到精確的玻璃溫度分佈。在有融化的切割中，表面受熱影響而產生的粗糙裂紋最深處介於1196.8 K到1248.7 K。因此可以利用模擬溫度分布來推估粗糙裂紋深度，並透過減少能量密度，找出降低粗糙裂紋深度的參數以助於雷射切割品質的事前評估。

According to previous works of our lab team, laser heat source on the ultra-thin glass will result in a high temperature that might cause the phase change on the surface. The temperature distribution was simulated by using COMSOL Multiphysics. In the process of heating glass, the phase change was considered. The temperature distribution should be closer to the real value.
The purpose of the thesis uses a simple physical model to explore the influence of laser heating on ultrathin glass. Combining the previous research analysis, the simulation of laser heating can be closer to the real behaviors. Then a numerical simulation method can be applied to the analysis of laser cutting on ultra-thin glass.
In this study, Al2O3 is chosen as the cutting material. After comparing the result of experiment with simulation, several variable parameters play very important roles. The phase change and heat transfer coefficient are especially significant and cannot be ignored. Moreover the reflectivity is important as well. It will reduce the power density directly. The smooth surface has a reflectivity of 0.25. Although it is difficult to accurately get the reflectivity of the rough surface, an estimated value by comparing the simulation with experiment can be obtained. The reflectivity is about 0.0744 on the rough plane in melting case. Finally, a more suitable simulation method is found to provide a precise temperature prediction of glass. In the melting case, the deepest rough crack produced by the influence of heat exists between the temperature of 1196.8 K and 1248.7 K. Therefore the simulated temperature distribution can be used to estimate the depth of rough crack. By decreasing the energy density, the proper set of parameters can be found to reduce the depth of rough crack. It will be helpful to assess the laser cutting quality before processing.

摘要 i
Abstract ii
Acknowledgment iv
Contents v
List of Tables ix
List of Figures x
Nomenclature xvi
Chapter 1 Introduction 1
1-1 Research Motivation and Background 1
1-2 Literature Review 3
1-2.1 Cutting Method 3
1-2.2 Principle of Glass Cutting 6
1-2.3 Ultrathin Glass 8
1-2.4 Material 10
1-2.5 Manufacturing Process 11
1-2.6 COMSOL Multiphysics 13
1-3 Research Goal 16
1-4 Thesis Outline 16
Chapter 2 Fundamental Principles 19
2-1 Laser Principle 19
2-1.1 Properties of Laser Radiation 19
2-1.2 Introduction of CO2 Laser 21
2-1.3 Gaussian Laser Sources 24
2-2 Heat Transfer Theory 31
2-2.1 Governing Equations 31
2-2.2 Discussion on Phase Change 33
2-2.3 Boundary Conditions 36
Chapter 3 Numerical Methods 39
3.1 COMSOL Multiphysics Verification 39
3.2 The Independence Test of Spatial Grid 44
3-2.1 Model 44
3-2.2 Mesh 47
3-2.3 Result 47
3-3 Numerical Method Setting 53
3-3.1 Numerical Model Setting 53
3-3.2 Governing Equations and Boundary Conditions 53
3-4 Numerical Simulation Procedures 54
3.5 Analysis of Material Parameters 57
3-5.1 Variable Parameters 57
3-5.2 Latent heat 58
Chapter 4 Results and Discussions 64
4-1 Influence of Parameters 64
4-1.1 Physical Model 64
4-1.2 Original Simulation Result 66
4-1.3 Considering Absorption Coefficient 66
4-1.4 Variable Heat Capacity and Thermal Conductivity 69
4-1.5 Latent Heat 72
4-2 Comparison of the Simulation with the Experiment 74
4-2.1 Introduction of Processing Parameters 74
4-2.2 Results Discussion 74
4-3 Discussion and Improvement of Simulation Results 81
4-3.1 Effect of Emissivity 81
4-3.2 Melting Temperature Range 83
4-3.3 Reflectivity 83
4-4 Results Discussion and Analysis 93
4-4.1 Comparison of Heat Affected Region 93
4-4.2 Non-Phase Change Case 96
4-4.3 The Melting Width 96
4-4.4 Melting Time 100
4-4.5 Estimating the Depth of Heat Affected Region 103
Chapter 5 Conclusions and Future Works 108
5-1 Conclusions 108
5-2 Future Works 110
References 111

1.Christoph Hermanns, “Laser Cutting of Glass, From Conference Vol. 4102, 2000.
2.Hyoung-Shik KANG, Soon-Kug HONG, Seok-Chang OH, Jong-Yoon CHOI, Min-Gyu SONG, “A study of cutting glass by laser, Proceedings of SPIE Vol. 4426, 2002.
3.M. Kumagai, K. K. Hamamatsu Photonics, T. Shizuoka Sakamoto, ; E. Ohmura, “Laser processing of doped silicon wafer by the Stealth Dicing, Semiconductor Manufacturing pp. 1-4, 2007
4.H. Y. Zheng, T. Lee, “Studies of CO2 laser peeling of glass substrates, IOP Journal of Micromechanics and Microengineering, Vol. 15, Number 11, 2005.
5.S. Hoehla, S. Garner, M. Hohmann, O. Kuhls, X. Li, A. Schindler, N. Fruehauf, “Full Color AM-LCDs on Flexible Glass Substrates, Corning Incorporated, 2010.
6.“Corning Gorilla Glass 2, Corning Incorporated, 2012.
7.A. Weber, S. Deutschbein, A. Plicht, A. Habeck, “Thin glass-polymer systems as flexible substrates for displays, SID Symposium Digest of Technical Papers, Vol. 33, pp. 53 – 55, 2002.
8.“Corning Gorilla Glass, Corning Incorporated, 2010.
9.Pascal Richet, “Heat capacity of Silicate glasses, Chemical Geology, Vol. 62, pp. 111-124, 1987.
10.Robert G. Berman, Thomas H. Brown, “Heat capacity of minerals in the system Na2O-K2O-CaO-MgO-FeO-Fe2O3-Al2O3-SiO2-TiO2-H2O-CO2: representation, estimation, and high temperature extrapolation, Contributions to Mineralogy and Petrology, Vol. 89 pp. 168-183, 1985.
11.鄭中緯, 沈威志, 陳政雄, 李依如, “平面顯示器製程設備技術專輯, 機械工業雜誌 315期, pp. 52 – 55, 2009.
12.楊憲東, 陳煜傑, 黃國興, “軟電R2R製程設備傳輸動態分析與控制, 機械工業雜誌 339期, pp. 36 – 42, 2011.
13.Industrial Technology Research Institute of Taiwan (ITRI) Available:
http://www.itri.org.tw/chi/msl/p4.asp?RootNodeId=070＆NavRootNodeId=0733＆NodeId=073322＆ArticleNBR=3045.
14.“Introduction to COMSOL Multiphysics, COMSOL Incorporated, 1998.
15.“Heating with a Moving Laser, COMSOL Incorporated, 2008.
16.“Phase Change, COMSOL Incorporated, 2008.
17.C. H. Tsai, C. S. Liou, “Fracture Mechanism of Laser Cutting With Controlled Fracture, Journal of Manufacturing Science and Engineering, Vol. 125, pp. 519-528, 2003.
18.R. Klein, “Laser Welding of Plastics, Wiley-VCH, 2011.
19.K. Imen, Susan D. Allen, “Pulse CO2 laser drilling of green alumina ceramic, IEEE Components, Packaging, and Manufacturing Technology Society, Vol. 22, Issue 4, 1999.
20.J. E. Shelby, “Introduction to Glass Science and Technology, Royal Society of Chemistry, 2005.
21.楊天祥,溫昌達,陳國聲,屈子正, “雷射劈裂超薄玻璃邊緣微裂紋模擬, 財團法人工業技術研究院南分院FY101分包學界研究計畫期末報告, 2012.
22.C. J. Tsai, C. J. Chen, “Formation of the breaking surface of alumina in laser cutting with a controlled fracture technique, Journal of Engineering Manufacture, Vol. 217, pp. 489-497, 2003.
23.D. Rosenthal, “A New Method of Determining Thermal Diffusivity at Various Temperatures, Los Angeles Engineering, 1946.
24.Ronald G. Munro, “Evaluated Material Properitied for a Sintered α-Alumina, Journal of the American Ceramic Society, Vol. 80, Issue 8, pp. 1919–1928, August 1997.
25.P. H. Zhang, R. Z. Chang, Z. Wei, H. Cao, and X. N. Zhou, “The Melting Point, Latent Heat of Solidification, and Enthalpy for Both Solid and Liquid Gt-Al2O3 in the Range 550-2400 K, International Journal of Thermophysics, Vol. 7, No. 4, 1986.
26.C. Yan, L. J. Li, D. S. Li, “Experimental Measurement on the Absorption Coefficients of Al2O3 Ceramics to CO2 Laser Radiation, 湖南大學學報自然科學版, Vol. 35, pp. 41-44, 2008.
27. T. Huang, C. D. Wen, “Thermal Analysis of Numerical Simulation on Laser Peeling of Ultrathin Glass, National Cheng Kung University Department of Mechanical Engineering Master’s Thesis, June, 2013.
28.Y. W. Huang, C. D. Wen, “Thermal simulation on laser peeling for ultrathin glass, National Cheng Kung University Department of Mechanical Engineering Master’s Thesis, June, 2014.