研究生: |
陳仙瑋 Sian-Wei Chen |
---|---|
論文名稱: |
高演色性白光發光二極體封裝 Package of White-Light LED with High Color Rendering Index |
指導教授: |
蘇忠傑
Jung-Chieh, Su |
口試委員: |
陳敬恒
Jing-Heng Chen 趙良君 Liang-Chiun Chao 林保宏 Pao-hung Lin |
學位類別: |
碩士 Master |
系所名稱: |
電資學院 - 光電工程研究所 Graduate Institute of Electro-Optical Engineering |
論文出版年: | 2008 |
畢業學年度: | 96 |
語文別: | 中文 |
論文頁數: | 78 |
中文關鍵詞: | 白光發光二極體 、演色性 、全方位反射器 |
外文關鍵詞: | white light LED, color rendering index, omnidirectional reflector |
相關次數: | 點閱:513 下載:8 |
分享至: |
查詢本校圖書館目錄 查詢臺灣博碩士論文知識加值系統 勘誤回報 |
近年來白光發光二極體(LED)已經成為未來照明光源新星。以藍光發光二極體激發黃色螢光粉的白光LED,因為演色性只能到達80左右,由於這個缺點如果想要用它來取代現有室內照明是不夠具有吸引性的。為了能夠達到高演色性的白光LED,本文提出使用波長在380 nm的紫外光發光二極體(UV-LED)激發一個新的螢光粉配方,並且與標準光源做比較。使用UV-LED激發紅藍綠三色螢光粉時,由於螢光粉的轉換特性導致所產生的白光LED演色性不高;另一方面使用藍光LED激發黃色YAG螢光粉有高轉換效率的優點。本文結合了這兩個要素提出使用UV-LED激發藍黃紅三色螢光粉,以達到演色性高於90,色座標接近理想白點的白光光源。使用紫外光發光二極體時會碰到另一個問題-紫外光的外漏-本文使用光子晶體又名全方位反射器完全能隙的概念,將一維光子晶體鍍膜片加入封裝結構中,達到將380 nm紫外光在任意入射角時全反射的功能。並且研究不同封裝結構對發光效率影響。使用光子晶體封裝不僅能防止紫外光外漏,還能提升發光效率。這一個新的白光結構在全方位反射器與螢光膠層存在一空氣層時會有最高的發光效率。利用這種封裝結構本研究能夠達到在色座標為 (0.319, 0.320) 時,CCT=6188K,Ra=93.7,發光效率9.5 lm/W的白光LED。由實驗結果得到,藉由控制螢光膠層的配方與濃度,就算不是使用高效率的紅藍綠螢光粉也可以達到高演色性的白光光源。
Although white-light light emitting diode (LED) has become a main goal for the new generation of illumination light source in the recent years, the color rendering index (CRI) for the blue LED chips excited yellow phosphors is around 80, and that falls short of the future lighting applications such as the street lighting. In order to achieve high CRI for white-light LEDs, we proposed a new phosphors blend for excitation using ultra violet LED (UV-LED) chips with wavelength around 380 nm, and compared the resultant light source with standard light source. Since the conversion characteristic of commercially available UV excited RGB phosphors may result in a low CRI white light source; on the other hand, use blue LED chips excited YAG based yellow phosphors has high conversion efficiency. We combined the characteristics of these phosphors to achieve phosphors conversion spectra with CRI above 90, the color coordinate approximates to the ideal white point. But we faced another problem “the leakage of UV light”. We use the full band gap idea of the photonic crystal (PhC.) or omni-directional reflector (ODR) by packaging the ODR with the conventional white-light LED. As a result of the UV beams can be omni-directionally reflected at any incidence. In this study the luminous efficiency of different package structures of ODR are also proposed. The ODR package will enhance the white light generation and prevent UV leak from the device. This novel white LED is constructed with an air gap between the phosphors layer and the ODR lead to the highest luminous efficiency. Specifically, the color coordinate for the light source made is (0.319, 0.320), the CRI has a value of 93.7, the correlated color temperature is 6188K and the luminous efficiency is 9.5 lm/W. The experimental data shows that a high CRI light source can be achieved without high quality RGB phosphors, by controlling the composition and concentration of phosphors blend layer.
[1]A. Zukauskas, R. Vaicekauskas, F. Ivanauskas, R. Gaska, and M. S. Shur, "Optimization of white polychromatic semiconductor lamps," Appl. Phy. Lett., vol. 80, no. 2, pp. 234~236, 14 Jan. 2002.
[2]Y. Ohno, "Spectral design considerations for white LED color rendering," SPIE Optical Engineering, vol. 44, no. 11, pp. 111302-1~111302-9, Nov. 2005.
[3]N. Narendran, L. Deng, R.M. Pysar, Y. Gu, and H. Yu, "Performance Characteristics of High-Power Light-Emitting Diodes," in Proc. SPIE Third Int. Conf. on Solid State Lighting, vol. 5187, pp. 267~275, 2004.
[4]P. Schlotter, R. Schmidt, and J. Schneider, "Luminescence conversion of blue light emitting diodes," Appl. Phys. A, vol. 64, pp. 417~418, 1997.
[5]P. Schlotter , J. Baur, Ch. Hielscher, M. Kunzer, H. Obloh, R. Schmidt, and J. Schneider, "Fabrication and characterization of GaN:InGaN:AlGaN double heterostructure LEDs and their application in luminescence conversion LEDs," Materials Science and Engineering B, vol. 59, pp. 390~394, 1999.
[6]Michael R. Krames, Oleg B. Shchekin, Regina Mueller-Mach, Gerd O. Mueller, Ling Zhou, Gerard Harbers, and M. George Craford, "Status and Future of High-Power Light-Emitting Diodes for Solid-State Lighting," IEEE J. of Display Technol., vol. 3, no. 2, pp. 160~175, June. 2007.
[7]Z. Z. Chen , J. Zhao, Z. X. Qin, X. D. Hu, T. J. Yu, Y. Z. Tong, Z. J. Yang, X. Y. Zhou, G. Q. Yao, B. Zhang, and G. Y. Zhang, "Study on the stability of the high-brightness white LED," phys. stat. sol. (b), vol. 241, no. 12, pp. 2664–2667, 14 Sep. 2004.
[8]Toshio Nishida, Tomoyuki Ban, and Naoki Kobayashic, "High-color-rendering light sources consisting of a 350-nm ultraviolet light-emitting diode and three-basal-color phosphors," Appl. Phy. Lett., vol. 82, no. 22, pp. 3817~3819, 2003.
[9]C.H. Kuo, J. K Sheu, S. J. Chang, Y. K. Su, L. W. Wu, J.M. Tsai, C. H. Liu, and R. K. Wu, "n-UV+Blue/Green/Red White Light Emitting Diode Lamps," Jpn. J. Appl. Phys., vol. 42, pp. 2284~2287, Apr. 2003.
[10]Yukio Narukawa, Junya Narita, Takahiko Sakamoto, Takao Yamada, Hiroki Narimatsu, Masahiko Sano, and T. Mukai, "Recent progress of high efficiency white LEDs," phys. stat. sol. (a), vol. 204, no. 6, pp. 2087~2093, 16 May. 2007.
[11]M. R. Krames, G. Christenson, D. Coffins, L. W. Cook , M. G. Craford, A. Edwards, R. M.Fletcher, N. Gardner, W. Goetz, W. Imler, E. Johnson, R. S. Kern, R. Khare, F. A. Kish, C.Lowery, M. J. Ludowise, R. Mann, M. Maranowski, S. Maranowski, P. S. Martin, J. O'Shea, S.Rudaz, D. Steigerwald, J. Thompson, J. J. Wierer, D. B. J. Yu, Y-L Chang, G. Hasnain, M. Hueschen, K. Killeen, C. Kocot, S. Lester, J. Miller, G.Mueller, R. Mueller-Mach, J. Rosner, R. Schneider, T. Takeuchi, and T. S. Tan, "High-brightness AlGaInN light-emitting diodes,"in Proc. SPIE Light-Emitting Diodes: Research, Manufacturing, and Applications IV, vol. 3938, pp. 2~12, 2000.
[12]I. Yu. Evstratov, V. F. Mymrin, S. Yu. Karpov, and Yu. N. Makarov, "Current crowding effects on blue LED operation," phys. stat. sol. (c), vol. 3, no. 3, pp. 1645–1648, 17 May. 2006.
[13]Ivan Eliashevich, Jean-Philippe Debray, Chuong A. Trant, Han Venugopalan, and Robert F. Karlicek, "InGaAlP and InGaN light-emitting diodes:high-power performance and reliability,"in Proc. SPIE Light-Emitting Diodes: Research, Manufacturing, and Applications IV, vol. 3938, pp. 44~51, 2000.
[14]C. M. Tsai, J. K. Sheu, W. C. Lai, Y. P. Hsu, P. T. Wang, C. T. Kuo, C. W. Kuo, S. J. Chang, and Y. K. Su, "Enhanced Output Power in GaN-Based LEDs With Naturally Textured Surface Grown by MOCVD," IEEE Electron Device Lett., vol. 26, no. 7, pp. 464~466, July. 2005.
[15]J. Baur, B. Hahn, M. Fehrer, D. Eisert, W. Stein, A. Plo¨ ssl, F. Ku¨hn, H. Zull, M. Winter, and V. Ha¨rle, "InGaN on SiC LEDs for High Flux and High Current Applications," phys. stat. sol. (a), vol. 194, no. 2, pp. 399–402, 1 Oct. 2002.
[16]J. J. Wierer, D. A. Steigerwald, M. R. Krames, J. J. O’Shea, M. J. Ludowise, G. Christenson, Y.-C. Shen, C. Lowery, P. S. Martin, S. Subramanya, W. Go¨ tz, N. F. Gardner, R. S. Kern, and S. A. Stockman, "High-power AlGaInN flip-chip light-emitting diodes," Appl. Phy. Lett., vol. 78, no. 22, pp. 3379~3381, 2 Apr. 2001.
[17]O. B. Shchekin, J. E. Epler, T. A. Trottier, T. Margalith, D. A. Steigerwald, M. O. Holcomb, P. S. Martin, and M. R. Krames, "High performance thin-film flip-chip InGaN–GaN light-emitting diodes," Appl. Phy.s Lett., vol. 89, pp. 071109-1~071109-3, 2006.
[18]"Introduction to Color Engineering," http://www.cmlab.csie.ntu.edu.tw/AMTCourse/Slides/04_Color%20Engineering.pdf, p. 8.
[19]Y. Ohno, "CIE Fundamentals for Color Measurements,"in IS&T NIP16 Conference Vancouver, Canada, 2000.
[20]E. F. Schubert, LIGHT-EMITTING DIODES. New York: Cambridge University, 2006.
[21]Ian Ashdown, Radiosity: A Programmer's Perspective: John Wiley & Sons, p. 14~27 2002.
[22]陳金嘉, "Radiometry and Photometry," http://163.23.219.175/wwwcontent/%A5%FA%AB%D7%BE%C7%BBP%A6%E2%AB%D7%BE%C7/Radiometry.ppt, p. 14.
[23]"A Guide to Integrating Sphere Theory and Applications," http://www.labsphere.com/data/userFiles/A%20Guide%20to%20Integrating%20Sphere%20Theory&Apps.pdf, p. 3.
[24]劉如熹, 紀喨勝, 紫外光發光二極體用螢光粉介紹. 臺北市: 全華科技圖書, 2005.
[25]陳仙瑋, 蘇忠傑, 陳文彥, 徐才峻, 林彥融, "以田口式實驗法調配白光發光二極體之CIE色座標," 2007年台灣光電科技研討會 ,臺北 ,台灣 , 2007.
[26]D. B. Judd, D. L. Macadam, G. Wyszecki, H. W. Budde, H. R. Condit, S. T. Henderson, and J. L. Simonds, "Spectral Distribution of Typical Daylight as a Function of Correlated Color Temperature," Journal of The Optical Society of America, vol. 54, no. 8, pp. 1031~1040, 1964.
[27]Y. Fink, J. N. Winn, S. Fan, C. Chen, J. Michel, J. D. Joannopoulos, and E. L. Thomas, "A Dielectric Omnidirectional Reflector," Science, vol. 282, pp. 1679~1682, 27 Nov. 1998.
[28]J. K. Kim, J.-Q. Xi, and E. F. Schubert, "Omni-directional reflectors for light-emitting diodes,"in Proc. SPIE Light-Emitting Diodes: Research, Manufacturing, and Applications X, vol. 6134, pp. 61340D-1~61340D-12, 2006.
[29]Y. Uchida and T. Taguchi, "Lighting theory and luminous characteristics of white light-emitting diodes,"SPIE Optical Engineering, vol. 44, no.12, pp. 124003-1~124003-9, 2005.