透過您的圖書館登入
IP:3.89.56.228
  • 學位論文

新型發光二極體封裝材料之開發:無機顆粒/矽樹脂複合材料之製備

Development of Silicone Inorganic Oxide Encapsulating Materials for Light Emitting Diodes (LEDs) Applications

指導教授 : 邱文英

摘要


此博士研究主要針對環保節能相關材料之開發,論文主要為新型發光二極體(Light emitting diode, LED)封裝膠材之開發以及其應用。 第一部分利用利用水解縮合法,直接於商用矽樹脂封裝材料中合成高折射率二氧化鈦無機顆粒,藉由醋酸之螯合作用,得到高折射率之透明二氧化鈦/矽樹脂光學材料(TiO2/AB),並應用於LED封裝材料,量測其封裝後之流明亮度。 第二部分利用水解縮合法,直接於商用矽樹脂封裝材料中合成高折射率二氧化鋯無機顆粒,同時藉由醋酸之螯合作用,使二氧化鋯顆粒於此商用矽樹脂封裝材中能穩定均勻分散,得到兼具高透明度以及高折射率之新型二氧化鋯/矽樹脂複合材料(ZrO2/AB);並將此ZrO2/AB做為LED原件之封裝材料,使發光二極體藉由封裝材料折射率的提升,以得到較佳之出光亮度。由流明量測之結果顯示,以原本商用矽樹脂封裝之LED亮度為3.97 lm,而將此ZrO2/AB做為封裝材後,其亮度可增加至4.35 lm,顯示藉由導入二氧化鋯以提升封裝材之折射率,可有效改進LED之出光亮度,顯示此二氧化鋯/矽樹脂複合材料具有應用於LED封裝之潛力。 第三部分則是利用水解縮合法,在商用矽樹脂封裝材料B劑以及GMA( glycidyl methacrylate)單體中,合成二氧化鋯顆粒,除了利用醋酸對二氧化鋯之螯合作用外,GMA的加入可有效防止二氧化鋯在反應過程中之顆粒聚集,並利用其雙鍵參與商用矽樹脂之聚合反應,以增加此無機二氧化鋯顆粒與矽樹脂之相容性,以得到高透明度之高折射率二氧化鋯及具環氧基高分子/矽樹脂複合材料(ZrO2/ABG),並將此ZrO2/ABG做為封裝材料,使LED得到較高之出光亮度。此外,我們利用光學基礎理論設計出簡易的光學模型,根據LED之晶片結構,模擬封裝材料以及passivation layer之折射率對於LED出光率之影響;最後,根據光學模型計算之結果,得到封裝材料以及passivation layer之最適折射率值,使LED可到達最佳之亮度。 第四部分目的為改進商用矽樹脂封裝材料於高低溫差異性極大的環境下,其應力釋放劇烈造成封裝可靠性不足之問題,本研究首先利用2-mercaptoethanol做為鏈轉移劑,合成PBA 寡聚物;藉由PBA寡聚物鏈段對無機顆粒之吸附作用,以原位水解縮合方式,將二氧化鋯顆粒直接生成於此PBA寡聚物鏈段上,形成二氧化鋯-寡聚物複合顆粒(ZrO2-PBA composite particle.)。並與商用矽樹脂均勻混合後,獲得含二氧化鋯-PBA寡聚物之矽樹脂複合材料,藉由其高折射率及高透明度之性質,做為LED封裝材料,並有效提升LED之發光亮度,除探討材料之穿透度、折射率、耐熱性以及其吸水性質之外,更著重於此複合封裝材料對於LED於高低溫差異性極大的環境下,對其信賴度之影響,以期改善原本商用矽樹脂封裝材料,因高低溫差產生之高應力,使得封裝可靠性不足的問題。

並列摘要


In our research, development of encapsulating material of light emitting diodes (LEDs) is the mainly purpose. In the first part (Chapter 2), optical hybrid materials with high refractive index were synthesis by in-situ production of titanium dioxide (TiO2) directly in a commercial-grade silicone resin via a sol-gel reaction. The optical transparency of the prepared TiO2/silicone hybrid film was investigated by UV-visible spectroscopy. These hybrid films with various TiO2 contents exhibited different refractive indices; the refractive index could reach 1.66 for the hybrid with 30 wt% of the TiO2. In addition, refractive index, thermal stability of the cured hybrid materials was also investigated. In the second part (Chapter 3), novel ZrO2/silicone hybrid materials (ZrO2/AB) useful for the encapsulation of light-emitting diodes (LEDs) are synthesized by an in situ sol-gel reaction of zirconium propoxide directly in a commercial-grade silicone resin by an in situ sol-gel reaction. By the chelation of the acetic acid, the ZrO2/AB hybrids exhibit high transparency owing to the well-dispersed ZrO2 particles in the silicone material, and their refractive index value also increased with increasing weight percentage of the ZrO2 in the hybrid. These high-refractive-index ZrO2/AB hybrids were then used as encapsulating materials to improve the luminous flux of the LEDs. From the results of the luminous flux measurement, the LED encapsulated with the pure silicone material has luminous flux of 3.97 lm. After encapsulated with the ZrO2/AB hybrid, the luminous flux of the LED was enhanced to a value of 4.35, which revealing that the increase in the refractive index of the encapsulating material by the incorporation of the ZrO2 could effectively improved the luminous flux of the LED, and these novel ZrO2/AB hybrids could also be considered as a suitable candidate as the encapsulating material for the LED. In the third part (Chapter 4), ZrO2 particles are synthesized directly in a commercial-grade silicone resin (AB) with the addition of a vinyl monomer (glycidyl methacrylate, GMA) by an in situ sol-gel reaction to obtain the silicone hybrid material (ZrO2/ABG). In addition to use the acetic acid as chelating agent, the addition of the GMA is able to retard the gelation rate of the metal alkoxide compound as well as the growing rate of ZrO2 during the sol-gel reaction, and also enhance the interfacial strength of the inorganic fillers with the silicone matrix by reacting with the silicone resin through a hydrosilation reaction via its vinyl group. The ZrO2/ABG hybrids thus exhibit excellent transparency and high refractive index. These ZrO2/ABG hybrids were then used as encapsulating materials to help the LEDs reach a higher luminous flux. Furthermore, according to the optical theory and the structure of the high-power LEDs, a simple simulation model was developed to estimate the luminous flux of the LEDs encapsulated with the ZrO2/ABG hybrids and the influence of the refractive index of the passivation layer on the luminous flux of the LEDs. Finally, with the help of this simulation model, an optimum combination of the encapsulating material and the passivation layer with appropriate refractive index values was obtained for achieving the highest luminous flux of LED. In the fourth part (Chapter 5), the purpose is to improve thermal mechanical property of the encapsulating materials in a very large temperature difference condition., thus decreasing the influence of the encapsulation on the reliability performance of the LED. The PBA(polybutylacrylate) oliogomer was firstly synthesized by a telomerization using 2-mercaptoethanol as a chain transfer agent. By the absorption to the inorganic particles and the carbonyl groups, the ZrO2 particles were produced on the oligomer chains of the PBA via an in situ sol-gel reaction to obtain the ZrO2-PBA composite particles, and subsequently mixed with a commercial-grade silicone resin to obtain the ZrO2-PBA/silicone hybrid materials (ZrO2-PBA/AB). The well-dispersed ZrO2-PBA domains lead to a high transparency and high refractive index of the ZrO2-PBA/AB hybrids, resulting in a higher luminous flux than the pristine silicone material. In addition to discuss the transmittance, refractive index, thermal resistance, and the water uptake of the ZrO2-PBA/AB hybrids, thermal stress evaluation of the LEDs encapsulated with the ZrO2-PBA/AB hybrids was also carried out in a thermal shock experiment with a temperature change from -35 °C to 125 °C within 15 mins. The results show that these ZrO2-PBA/AB hybrids have a lower thermal stress and exhibit a better mechnical resistance against the thermal shock, and the reliability performance of the LEDs are also greatly improved as encapsulated with the ZrO2-PBA/AB hybrids.

參考文獻


2. Tsou C, Chang C, Lai T and Huang C. Microsystem Technologies 2013;19(11):1851-1862.
4. Liu Z, Liu S, Wang K and Luo X. Frontiers of Optoelectronics in China 2009;2(2):119-140.
20. Ram Srinivasan RJDn, Gene Ice, Burtron H. Davis. JOURNAL OF MATERIALS RESEARCH 1991;6(6):1287-1292.
26. Ram Srinivasan RJDn, Gene Ice, Burtron H. Davis. JOURNAL OF MATERIALS RESEARCH 1991;6(6):1287-1292.
7. Lee JW, Cho J, Yoon S, Kim H, Sung YJ, Sone C, Park Y and Kim TG. High extraction efficiency light-emitting-diodes using hemispherical corrugated interface substrate. In: Woo JC, Hasegawa H, Kwon YS, Yao T and Yoo KH, editors. Compound Semiconductors 2004, Proceedings, vol. 184. Bristol: Iop Publishing Ltd, 2005. pp. 333-339.

延伸閱讀