本論文的主要目的是透過傳統點膠技術及不改變原有封裝材料與不添加設備方式進行低成本和有效率的改善發光二極體封裝結構的光熱及可靠度性能之研究。本論文提出封裝膠摻雜二氧化鈦奈米粒子的結構設計與螢光粉沉澱技術應用於製作發光二極體封裝結構。
高折射率及高散射能力的二氧化鈦奈米粒子摻雜入封裝矽膠以改善LED封裝結構之研究中，第一部份為在封裝膠特定區域摻雜入二氧化鈦奈米粉末，透過不同區域的摻雜，我們成功地製作低功率藍色LED封裝結構並證實將二氧化鈦奈米粒分散於LED晶粒周圍形成漸變折射率結構，可有效提升3 %光輸出及抑制光在長期操作下的衰減。第二部份我們深入探討二氧化鈦奈米粒分散於矽膠之低功率藍色LED封裝結構可靠度測試及接面溫度研究，透過進一步最佳化的二氧化鈦濃度摻雜研究顯示，二氧化鈦摻雜元件不僅能提升光取出效率4.1 %、封裝矽膠折射率也被證實能有效提高(n = 1.54 到 1.55)，並在不同環境條件及長時間可靠度燒測元件中結果顯示，二氧化鈦摻雜元件相較於傳統純矽膠元件都有較低的接面溫度，結果證實降低熱在封裝體的內部累積、就能有效的改善封裝元件的可靠度並延緩光輸出的衰減。此外，隨著市場需求，高功率高亮度晶片成為市場主流，封裝矽膠的材料特性是影響元件光熱特性的重大關鍵，因此第三部分我們深入探討二氧化鈦奈米粒分散於甲基矽膠(n = 1.41)及苯基矽膠(n = 1.54)之高功率藍色LED封裝結構光取出效率及耐熱性研究。實驗結果顯示二氧化鈦奈米粒適當地的摻雜入低折射率的甲基矽膠及高折射率的苯基矽膠，都可有效地改善純矽膠封裝結構後之光、耐熱、可靠度特性。為了進一步大幅度的改善光熱特性，第四部分研究為透過二氧化鈦摻雜矽膠層與矽膠透鏡製作藍色LED封裝結構，此結構採用傳統封裝矽膠材料及點膠方式製作自然成形的矽膠透鏡，並搭配摻雜二氧化鈦分散至晶片表面，因此，此提出元件同時形成雙層漸變折射率及矽膠透鏡的封裝結構，可大幅度減少光內部反射損失並增加側出光量，並能有效改善光取出效率24.5%、減少接面溫度12.1℃。第五部分為在封裝螢光膠摻雜入二氧化鈦，製作高功率白色LED封裝結構。實驗結果顯示透過散射能力與矽膠折射率的增加，能有效的減少光的混合損失，因此提出的封裝結構可有效改善角度色溫差39 %、減少螢光粉使用量5 %、並提升光通量2.7 %、減少接面溫度3.7℃。
最後，藉由螢光粉沉澱技術應用於LED封裝結構之研究中，我們成功地製作高效能漸變敷型式白色LED封裝結構，此方法能有效地將螢光粉均勻分散至晶粒周圍，並改變導線架內的螢光粉濃度變化，形成漸變折射率與敷型式螢光粉結構，實驗結果顯示可有效減少色溫差75%、提升2.2%流明輸出、減少接面溫度3.7℃。

The main purpose of this dissertation is to produce low-cost and high efficiency in optical-thermal and reliability performance of semiconductor light-emitting diodes (LEDs) package by dispensing technique without changing package material and without additional optical equipment. The purpose of this dissertation includes LEDs structures design by doping TiO2 into silicone encapsulation and phosphor sedimentation technology for applying in a fabrication of LEDs package structure.
To improve the performance of LED package, high refractive index of encapsulation material and superior light scattering capability of TiO2 nanoparticles (NPs) were used and investigated. In the first part, TiO2 NPs doping in specific region of encapsulation silicone to produce blue low-power LED package was studied. We successfully produced and confirmed that TiO2 doping around the LED chip only to form graded-index structure not only can increase light output by 3 % but also inhibit the light degradation under the stress test. In the second part, the light output and reliability testing of the GaN-based low-power blue LED packaging have been carried out with TiO2 NPs doped into silicone encapsulation. We further studied on optimization of TiO2-doped silicone concentration to improve the light extraction efficiency (LEE) by 4.1 %, refractive index of silicone encapsulation (from n=1.54 to n=1.55), and the reliability of LEDs compared with that of LEDs without TiO2 NPs doping. The results show that internal reflection loss at the silicone encapsulation between air interfaces was reduced, thereby significantly reducing the heat accumulation in LED packaging. In addition, high-power and high brightness LED chip has become the market mainstream with the increase in market demand. Therefore, the property of silicone-encapsulated material is a major issue and has an influence on the light and heat characteristics. In the third part, the effects of methyl ( n=1.41) and phenyl ( n=1.54) silicone encapsulation material doped with TiO2 NPs on the LEE and heat resistance of GaN-based blue high-power LEDs were investigated. The results show that TiO2 properly doped in low refractive index of methyl silicone or high refractive index of phenyl silicone encapsulation materials effectively improved the LEE and thermal reliability of LEDs. To further significant improvement in the optical-thermal characteristics, in the fourth part, we investigated and proposed a dispensing technique to produce graded structures blue LED consisting of a TiO2-doped silicone layer and a half-spherical silicone lens on top. The LED achieved a LEE increase of 24.5% and a junction temperature reduction of 12.1°C compared with a conventional single-layer encapsulated LED. In the fifth part, white LEDs assembled by doping TiO2 with phosphor silicone encapsulation were investigated. The resulting structure offers appropriate refractive efficiency and light scattering ability, which reduces the light loss due to color mixing inside the packages, thereby improving lumen output by 2.7% and correlated color temperature (CCT) deviation by 39% and reducing junction temperature by 6.5°C and the required amount of phosphor by 5%.
Finally, we studied on graded-index conformal phosphor structure fabricated of white LEDs and the production of highly uniform CCT and lumen output using a simple dispensing sedimentation technique. In this method, the phosphor was coated on the top surface of the LED chip so as to simultaneously form a thin conformal phosphor and a graded-index phosphor. Consequently, the CCT deviation, lumen output, and junction temperature were improved by 75%, 2.2%, and 3.7ºC respectively at 350 mA current, compared with conventional phosphor structures.

[1] E. F. Schubert, T. Gessmann, and J. K. Kim, " Light emitting diodes" Wiley Online Library, 2005.
[2] 陳隆建，"發光二極體之原理與製程" 全華科技圖書，2010.
[3] H. J. Round, "A note on carborundum," Electrical world, vol. 19, pp. 309-312, 1907.
[4] H. Welker, "On new semiconducting compounds," Zeitschrift fur Naturforschung, vol. 7a, pp. 744-749, 1952.
[5] H. Welker, "On new semiconducting compounds II," Zeitschrift fur Naturforschung, vol. 8a, pp. 248-251, 1953.
[6] R. Braunstein, "Radiative transitions in semiconductors," Phys. Rev, vol. 99, pp. 1892-1893, 1955.
[7] J. N. Holonyak and S. F. Bevacqua,"Coherent (visible) light emission from Ga (As1− xPx) junctions," Appl. Phys. Lett., vol. 1, pp. 82-83, 1962.
[8] H. P. Maruska and J. J. Tietjen, "The preparation and properties of vapour-deposited single-crystal-line GaN " Appl. Phys. Lett., vol. 15, pp. 327-329, 1969.
[9] J. Pankove, E. Miller, D. Richman, and J. Berkeyheiser, "Electroluminescence in GaN," . Luminescence, vol. 4, pp. 63-66, 1971.
[10] H. Amano, N. Sawaki, I. Akasaki, and Y. Toyoda, "Metalorganic vapor phase epitaxial growth of a high quality GaN film using an AlN buffer layer," Appl. Phys. Lett., vol. 48, pp. 353-355, 1986.
[11] H. Amano, M. Kito, K. Hiramatsu, and I. Akasaki, "P-type conduction in Mg-doped GaN treated with low-energy electron beam irradiation (LEEBI)," Jpn. J. Appl. Phys., vol. 28, pp. L2112-L2114, 1989.
[12] S. Nakamura and T. Mukai, "High-quality InGaN films grown on GaN films," Jpn. J. Appl. Phys., vol. 31, pp. L457-L459, 1992.
[13] P. Kung, C. Sun, A. Saxler, H. Ohsato, and M. Razeghi, "Crystallography of epitaxial growth of wurtzite‐type thin films on sapphire substrates," J. Appl. Phys., vol. 75, pp. 4515-4519, 1994.
[14] N. Iwasa, S. Nakamura, and M. Senoh, "Method of manufacturing p-type compound semiconductor,"U.S. Patents 5,306,662, Apr. 26, 1994.
[15] S. Nakamura, M. Senoh, N. Iwasa, S. Nagahama, T. Yamada, and T. Mukai, "Superbright green InGaN single-quantum-well-structure light-emitting diodes," Jpn. J. Appl. Phys., vol. 34, pp. L1332-L1335, 1995.
[16] T. P. Chen and K. H. Huang, "Light emitting diode structure," U.S. Patents 5,661,742, Aug. 26, 1997.
[17] T. Sasaki and T. Matsuoka, "Substrate‐polarity dependence of metal‐organic vapor‐phase epitaxy‐grown GaN on SiC," J. Appl. Phys., vol. 64, pp. 4531-4535, 1988.
[18] C. J. Sun, P. Kung, A. Saxler, H. Ohsato, E. Bigan, and M. Razeghi, "Thermal stability of GaN thin films grown on (0001) Al2O3, (01-12) Al2O3, and (0001)Si SiC substrates, " J. Appl. Phys., vol. 76, pp. 236-241, 1994.
[19] Y. Sun, Y. H. Cho, H. M. Kim, and T. W. Kang, "High efficiency and brightness of blue light emission from dislocation-free InGaN∕GaN quantum well nanorod arrays," Appl. Phys. Lett., vol. 87, pp. 093115, 2005.
[20] M. Yamada, T. Mitani, Y. Narukawa, S. Shioji, I. Niki, S. Sonobe, K. Deguchi, M. Sano and T. Mukai, "InGaN-based near-ultraviolet and blue-light-emitting diodes with high external quantum efficiency using a patterned sapphire substrate and a mesh electrode," J. Appl. Phys., vol. 41, pp. L1431-L1433, 2002.
[21] T. P. Chen, T. C. Hsu, C. Y. Luo, M. C. Hsu, and T. X. Lee, "Improvement in light extraction efficiency of high brightness ingan-based light emitting diodes," Proc. SPIE, vol. 7216, pp. 1-10, 2009.
[22] H. C. Chen, K. J. Chen, C. H. Wang, C. C. Lin, C. C. Yeh, H. H. Tsai, M. H. Shih, H.C. Kuo, and T. C. Lu,., "A novel randomly textured phosphor structure for highly efficient white light-emitting diodes," Nanoscale Res. Lett., vol. 7, pp. 188, 2012.
[23] F. W. Mont, J. K. Kim, M. F. Schubert, H. Luo, E. F. Schubert, and R. W. Siegel, "High refractive index nanoparticle-loaded encapsulants for light-emitting diodes," Proc. SPIE, vol. 6486, pp. 64861C, 2007.
[24] F. W. Mont, J. K. Kim, M. F. Schubert, E. F. Schubert, and R. W. Siegel, "High-refractive-index TiO2-nanoparticle-loaded encapsulants for light-emitting diodes," J. Appl. Phys., vol. 103, pp. 083120, 2008.
[25] S. Liu and X. Luo, "LED packaging for lighting applications : design, manufacturing, and testing" John Wiley & Sons, 2011.
[26] 蘇永道，吉愛華，趙超， " LED構裝技術"，五南文化事業, 2011。
[27] 劉如熹，"白光發光二極體製作技術-由晶粒金屬化至封裝"，全華科技圖書股份有限公司，2008。
[28] 洪瑞華，陳建宇，賴芳儀，呂紹旭，吳孟奇，黃麒甄，梁從主，歐崇仁，林俊良，劉如熹，黃琬瑜，朱紹舒，郭文凱，謝其昌，"LED 工程師基礎概念與應用"五南文化事業, 2012.
[29] 郭浩中， 賴芳儀，郭守義，"LED 原理與應用第二版" 五南文化事業, 2012.
[30] J. P. You, Y. H. Lin, N. T. Tran, and F. G. Shi, "Phosphor concentration effects on optothermal characteristics of phosphor converted white light-emitting diodes," J. Electron. Packaging, vol. 132, pp. 031010, 2010.
[31] M. W. Chang, H. S. Won, H. Kim, and J. M. Lee, "Enhancement of light extraction efficiency in light-emitting diodes with prism-type textured top surface," Jpn. J. Appl. Phys., vol. 46, pp. 6673-6675, 2007.
[32] T. Fujii1, Y. Gao1, R. Sharma1, E. L. Hu1, S. P. DenBaars1 and S. Nakamura1, " Increase in the extraction efficiency of gan-based light-emitting diodes via surface roughening," vol. 84, pp. 855-857, 2004.
[33] J. Cho, H. Kim, H. Kim, J. W. Lee, S. Yoon, C. Sone, Y. Park, and E. Yoon, "Simulation and fabrication of highly efficient InGaN‐based LEDs with corrugated interface substrate," Phys. Status Solidi (C), vol. 2, pp. 2874-2877, 2005.
[34] X. Wang, W. Fu, P. Lai, and H. Choi, "Evaluation of InGaN/GaN light-emitting diodes of circular geometry," Opt. Express, vol. 17, pp. 22311-22319, 2009.
[35] M. Ma, F. W. Mont, X. Yan, J. Cho, E. F. Schubert, G. B. Kim, and C. Sone, "Effects of the refractive index of the encapsulant on the light-extraction efficiency of light-emitting diodes," Opt. Express, vol.19, pp. A1135–A1140, 2011.
[36] J. Ye, Z. Zou, M. Oshikiri, A. Matsushita, M. Shimoda, M. Imai, et al., "A novel hydrogen-evolving photocatalyst InVO4 active under visible light irradiation," Chem. Phys. Lett., vol. 356, pp. 221-226, 2002.
[37] L. Znaidi, R. Seraphimova, J. F. Bocquet, C. Colbeau-Justin, and C. Pommier, "A semi-continuous process for the synthesis of nanosize TiO2 powders and their use as photocatalysts," Mater. Res. Bull., vol. 36, pp. 811-825, 2001.
[38] Y. Cheng, H. Sun, W. Jin, and N. Xu, "Effect of preparation conditions on visible photocatalytic activity of titania synthesized by solution combustion method," Chin. J. of Chem. Eng., vol. 15, pp. 178-183, 2007.
[39] H. S. Lee and J. W. Yoo, "Yellow phosphors coated with TiO2 for the enhancement of photoluminescence and thermal stability," Appl. Surf. Sci., vol. 257, pp. 8355-8359, 2011.
[40] Y. H. Lin, J. P. You, Y. C. Lin, N. T. Tran, and F. G. Shi, "Development of high-performance optical silicone for the packaging of high-power leds," components and packaging technologies, IEEE Trans. Components Packag. Technol., vol. 33, pp. 761-766, 2010.
[41] T. Yanagisawa and T. Kojima, "Long-term accelerated current operation of white light-emitting diodes," J. Luminescence, vol. 114, pp. 39-42, 2005.
[42] C. C. Tsai, M. H. Chen, Y. C. Huang, Y. C. Hsu, Y. T. Lo, Y. J. Lin, J. H. Kuang, S. B. Huang, H. L. Hu, Y. I. Su, and W. H. Cheng, "Decay mechanisms of radiation pattern and optical spectrum of high-power LED modules in aging test," IEEE J. Sel. Top. Quantum Electron., vol. 15, pp. 1156-1162, 2009.
[43] H. Luo, J. K. Kim, E. F. Schubert, J. Cho, C. Sone, and Y. Park, "Analysis of high-power packages for phosphor-based white-light-emitting diodes," Appl. Phys. Lett., vol. 86, pp. 243505, 2005.
[44] Y. C. Hsu, Y. K. Lin, M. H. Chen, C. C. Tsai, J. H. Kuang, S. B. Huang , and W. H. Cheng, "Failure mechanisms associated with lens shape of high-power LED modules in aging test," IEEE Trans. Electron Devices, vol. 55, pp. 689-694, 2008.
[45] A. N. Noemaun, F. W. Mont, G. B. Lin, J. Cho, E. Fred Schubert, G. Bum Kim, C. Sone, and J. Kyu Kim, "Optically functional surface composed of patterned graded-refractive-index coatings to enhance light-extraction of GaInN light-emitting diodes," J. Appl. Phys, vol. 110, pp. 054510, 2011.
[46] Y. K. Su, K. C. Chen, C. L. Lin, and H. C. Hsu, "Enhancement in light extraction of GaN-based light-emitting diodes with high reflectivity electrodes," IEEE Photonics Technol. Lett., vol. 23, pp. 1793-1795, 2011.
[47] K. Chen, Y. Su, C. L. Lin, and H. Hsu, "Laser scribing of sapphire substrate to increase side light extraction of GaN-based light emitting diodes," J. Lightwave Technol., vol. 29, pp. 1907-1912, 2011.
[48] J. Y. Cho, K. J. Byeon, H. Park, H. S. Kim, and H. Lee, "Formation of TiO2 nano pattern on GaN-based light-emitting diodes for light extraction efficiency," Jpn. J. Appl. Phys., vol. 49, pp. 102103, 2010.
[49] C. Y. Cho, N. Y. Kim, J. W. Kang, Y. C. Leem, S. H. Hong, W. Lim, S. T. Kim, and S. J. Park, "Improved light extraction efficiency in blue light-emitting diodes by SiO2-Coated ZnO nanorod arrays," Appl. Phys. Express, vol. 6, pp. 042102, 2013.
[50] J. H. Shin, H. J. Choi, K. S. Han, S. Ra, K. W. Choi, and H. Lee, "Effect of anti-reflective nano-patterns on LED package," Curr. Appl. Phys., vol. 13, pp. S93-S97, 2013.
[51] R. Y. Yu, S. Z. Jin, P. Liang, S. Y. Cen, and L. Wang, "Monte carlo simulation on leds graded-refractive-index-encapsulation," Acta Photonica Sin, vol. 39, pp. 2200-2203, 2010.
[52] J. S. Kim, S. Yang, and B. S. Bae, "Thermally stable transparent Sol−Gel based siloxane hybrid material with high refractive index for light emitting diode (LED) encapsulation," Chem. Mater., vol. 22, pp. 3549-3555, 2010.
[53] P. Tao, Y. Li, A. Rungta, A. Viswanath, J. Gao, B. C. Benicewicz, and L. S. Schadler, "TiO2 nanocomposites with high refractive index and transparency," J. Mater. Chem., vol. 21, pp. 18623, 2011.
[54] H. I. Elim, B. Cai, Y. Kurata, O. Sugihara, T. Kaino, T. Adschiri, A. Tadafumi, A. L. Chu, and N. Kambe, "Refractive index control and Rayleigh scattering properties of transparent TiO2 nanohybrid polymer," J. Phys. Chem, vol. 113, pp. 10143-10148, 2009.
[55] P. T. Chung, C. T. Yang, S. H. Wang, C. W. Chen, A. S. T. Chiang, and C. Y. Liu, "ZrO2/epoxy nanocomposite for LED encapsulation," Mater. Chem. Phys., vol. 136, pp. 868-876, 2012.
[56] F. Jiang, W. Liu, Y. Li, W. Fang, C. Mo, M. Zhou, and H. Liu, "Research on the junction-temperature characteristic of GaN light-emitting diodes on Si substrate," J. Lumin, vol. 122-123, pp. 693-695, 2007.
[57] S. C. Yang, P. Lin, C. P. Wang, S. B. Huang, C. L. Chen, P. F. Chiang, A. T. Lee, and M. T. Chu, "Failure and degradation mechanisms of high-power white light emitting diodes," Microelectron. Reliab., vol. 50, pp. 959-964, 2010.
[58] D. A. Lock, S. R. Hall, A. Prins, B. Crutchley, S. Kynaston, and S. J. Sweeney, "LED junction temperature measurement using generated photocurrent," J. Disp. Technol., vol. 9, pp. 396-401, 2013.
[59] N. C. Chen, C. M. Lin, Y. K. Yang, C. Shen, T. W. Wang, and M. C. Wu, "Measurement of junction temperature in a nitride light-emitting diode," Jpn. J. Appl. Phys., vol. 47, pp. 8779-8782, 2008.
[60] P. F. Ji and C. H. Moon, "Change of effective thermal resistance of LED package according to an input current level," Solid-State Electron., vol. 85, pp. 1-5, 2013.
[61] B. J. Li, C. H. Chang, Y. K. Su, and K. J. Gan, "Thermal dissipation of high-brightness light emitting diode by using multiwalled carbon nanotube/SiC composites," Jpn. J. Appl. Phys., vol. 50, pp. 06GE09, 2011.
[62] F. Rao, Z. C. Ge, and J. L. Zhu, "Effect of temperature and current on luminous efficiency of high power led," Adv. Mater. Res, vol. 347-353, pp. 310-313, 2011.
[63] T. Li, J. Zhang, H. Wang, Z. Hu, and Y. Yu, "High-performance light-emitting diodes encapsulated with silica-filled epoxy materials," ACS Appl. Mater. Interfaces, vol. 5, pp. 8968-81, 2013.
[64] J. S. Wang, C. C. Tsai, J. S. Liou, W. C. Cheng, S. Y. Huang, G. H. Chang, and W. H. Cheng, "Mean-time-to-failure evaluations of encapsulation materials for LED package in accelerated thermal tests," Microelectron. Reliab., vol. 52, pp. 813-817, 2012.
[65] F. K. Wang and T. P. Chu, "Lifetime predictions of LED-based light bars by accelerated degradation test," Microelectron. Reliab., vol. 52, pp. 1332-1336, 2012.
[66] M. Meneghini, M. Dal Lago, N. Trivellin, G. Mura, M. Vanzi, G. Meneghesso, and E. Zanoni, "Chip and package-related degradation of high power white LEDs," Microelectron. Reliab., vol. 52, pp. 804-812, 2012.
[67] X. Liu and W. Fang, "Analysis on the failure modes and mechanisms of LED packaging," ICEPT-HDP, 2012, pp. 1500-1502.
[68] Y. Sun, Y. H. Cho, H. M. Kim, and T. W. Kang, "High efficiency and brightness of blue light emission from dislocation-free InGaN∕GaN quantum well nanorod arrays," Appl. Phys. Lett, vol. 87, pp. 093115, 2005.
[69] C. F. Tsai, Y. K. Su, and C. L. Lin, "Further improvement in the light output power of InGaN-based light emitting diodes by patterned sapphire substrate with KOH wet-chemical etching on sidewall," Jpn. J. Appl. Phys, vol. 51, pp. 01AG04, 2012.
[70] S. H. Kim, Y. H. Song, S. R. Jeon, T. Jeong, J. Y. Kim, J. S. Ha, W. H. Kim, J. H. Baek, G. M. Yang, and H. J. Park, "Enhanced luminous efficacy in phosphor-converted white vertical light-emitting diodes using low index layer," Opt. Express, vol. 21, pp. 6353-6359, 2013.
[71] X. Wang, W. Fu, P. Lai, and H. Choi, "Evaluation of InGaN/GaN light-emitting diodes of circular eometry," Opt. Express, vol. 17, pp. 22311-22319, 2009.
[72] S. Yang, J. S. Kim, J. Jin, S. Y. Kwak, and B. S. Bae, "Cycloaliphatic epoxy oligosiloxane-derived hybrid materials for a high-refractive index LED encapsulant," J. Appl. Polym. Sci., vol. 122, pp. 2478-2485, 2011.
[73] Y. H. Lin, J. P. You, Y. C. Lin, N. T. Tran, and F. G. Shi, "Development of high-performance optical silicone for the packaging of high-power LEDs," IEEE Trans. Compon. Packag. Technol., vol. 33, pp. 761-766, 2010.
[74] M. Zhang, G. Lin, C. Dong, and L. Wen, "Amorphous TiO2 films with high refractive index deposited by pulsed bias arc ion plating," Surf. Coat. Technol., vol. 201, pp. 7252-7258, 2007.
[75] J. Ye, Z. Zou, M. Oshikiri, A. Matsushita, M. Shimoda, M. Imai, and T. Shishido, "A novel hydrogen-evolving photocatalyst InVO4 active under visible light irradiation," Chem. Phys. Lett., vol. 356, pp. 221-226, 2002.
[76] M. H. Chang, D. Das, P. V. Varde, and M. Pecht, "Light emitting diodes reliability review," Microelectron. Reliab., vol. 52, pp. 762-782, 2012.
[77] Y. C. Lin, J. P. You, N. T. Tran, Y. He, and F. G. Shi, "Packaging of phosphor based high power white leds: effects of phosphor concentration and packaging configuration," J. Electron. Packag., vol. 133, pp. 011009, 2011.
[78] B. Cai, O. Sugihara, H. I. Elim, T. Adschiri, and T. Kaino, "A novel preparation of high-refractive-index and highly transparent polymer nanohybrid composites," Appl. Phys. Exp., vol. 4, pp. 092601, 2011.
[79] R. Hu, X. Luo, H. Feng, and S. Liu, "Effect of phosphor settling on the optical performance of phosphor-converted white light-emitting diode," J. Lumin., vol. 132, pp. 1252-1256, 2012.
[80] K. J. Chen, B. C. Lin, H. C. Chen, M. H. Shih, C. H. Wang, H. T. Kuo, and S. H. Chien, P. T. Lee, C. C. Lin, and H. C. Kuo, "Effect of the thermal characteristics of phosphor for the conformal and remote structures in white light-emitting diodes," IEEE Photon. J., vol. 5, pp. 8200508, 2013.
[81] H. T. Huang, C. C. Tsai, and Y. P. Huang, "Conformal phosphor coating using capillary microchannel for controlling color deviation of phosphor-converted white light-emitting diodes," Opt. Exp., vol. 18, pp. A201–A206, 2010.
[82] R. Yu, S. Jin, S. Cen, and P. Liang, "Effect of the phosphor geometry on the luminous flux of phosphor-converted light-emitting diodes," IEEE Photon. Technol. Lett., vol. 22, pp. 1765-1767, 2010.
[83] S. L. Hsiao, N. C. Hu, and C. C. Wu, "Reducing the required amount of phosphor in warm white-light-emitting diodes by enhancing the scattering effect of wavelength conversion layer: a simulation study," Appl. Phys. Exp., vol. 6, pp. 032102, 2013.
[84] Y. R. Kang, K. H. Kim, W. H. Kim, S. W. Jeon, M. S. Jang, J. S. Kwak, et al., "Utilization of silicone microspheres: improving color uniformity and reducing the amount of phosphor used in white light-emitting diodes," IEEE Trans. Compon., Packag., Manuf. Technol., vol. 3, pp. 1453 - 1457, 2013.
[85] H. C. Chen, K. J. Chen, C. C. Lin, C. H. Wang, H. V. Han, H. H. Tsai, H. T. Kuo, S. H. Chien, M. H. Shih, and H. C. Kuo, "Improvement in uniformity of emission by ZrO2 nano-particles for white LEDs," Nanotechnology, vol. 23, pp. 265201, 2012.
[86] Y. Narukawa, I. Niki, K. Izuno, M. Yamada, Y. Murazaki, and T. Mukai, "Phosphor-conversion white light emitting diode using InGaN near-ultraviolet chip," Jpn. J. Appl. Phys., vol. 41, pp. L371, 2002.
[87] J. H. Lee, D. Y. Lee, B. W. Oh, and J. H. Lee, "Comparison of InGaN-based LEDs grown on conventional sapphire and cone-shape-patterned sapphire substrate," IEEE Trans. Electron Devices,, vol. 57, pp. 157-163, 2010.
[88] J. K. Park, C. H. Kim, S. H. Park, H. D. Park, and S. Y. Choi, "Application of strontium silicate yellow phosphor for white light-emitting diodes," Appl. Phys. Lett., vol. 84, pp. 1647-1649, 2004.
[89] H. Zheng, S. Liu, and X. Luo, "Enhancing angular color uniformity of phosphor-converted white light-emitting diodes by phosphor dip-transfer coating," J. Lightwave Technol., vol. 31, pp. 1987-1993, 2013.
[90] K. J. Chen, H. V. Han, B. C. Lin, H. C. Chen, M. H. Shih, S. H. Chien, K. Y. Wang, H. H. Tsai, P. Yu, P. T. Lee, C. C. Lin, and H. C. Kuo, "Improving the angular color uniformity of hybrid phosphor structures in white light-emitting diodes," IEEE Electron Device Lett., vol. 34, pp. 1280-1282, 2013.
[91] R. Hu, B. Cao, Y. Zou, Y. Zhu, S. Liu, and X. Luo, "Modeling the light extraction efficiency of bi-layer phosphors in white LEDs," IEEE Photon. Technol. Lett., vol. 25, pp. 1141, 2013.
[92] K. C. Lee, D. G. Kim, S. M. Kim, H. S. Oh, and J. H. Baek, "The influence of phosphor sedimentation on the white LEDs with different structure chip," Asia Communications and Photonics Conference and Exhibition, pp. 83120E-83120E-4, 2011.
[93] K. J. Chen, H. C. Chen, C. C. Lin, C. H. Wang, C. C. Yeh, H. H. Tsai, S. H. Chien, M. H. Shih and H. C. Kuo, "An investigation of the optical analysis in white light-emitting diodes with conformal and remote phosphor structure," J. Display Technol., vol. 9, pp. 915-920, 2013.
[94] Y. Zhu and N. Narendran, "Investigation of remote-phosphor white light-emitting diodes with multi-phosphor layers," Jpn. J. Appl. Phys., vol. 49, pp. 100203, 2010.