大功率LED器件封装材料的研究现状

LED灯具有高效节能、绿色环保等优点,在照明市场的前景备受各国瞩目,对LED封装材料的研究也备受关注.本文介绍环氧树脂及有机硅的LED封装材料的研究现状以及存在的问题.有机硅封装材料被认为是大功率LED器件封装的最佳材料.高性能有机硅封装材料将具有广阔的应用前景及巨大的经济效益.     

LED封装用有机硅材料的制备与性能

有机硅材料是化工新材料产业的重要组成部分,该材料用于半导体白光照明LED灯中的应用前景备受关注,进而也加深了材料在LED中运用的相关研究。就有机硅封装材料而言,其主要是通过混合复合硅树脂与有机硅油,再基于适当的条件下催化固化而成的一种透明材料,当然,也正是基于此项材料所具有的透明与耐热性能,故可运用于LED灯的制作。主要将基于有机硅封装材料本身所具有的透光性对LED出光效率的影响进行研究,以望能提升LED灯的制备效果。     

高功率型LED封装新材料的研究进展

随着发光二极管(LED)功率和亮度的不断提高,封装材料已成为制约LED进入照明领域的关键技术之一。综述了改性环氧树脂和有机硅LED封装材料的研究进展,并展望了改性环氧树脂和有机硅LED封装材料的发展前景。     

LED电子器件封装用有机硅材料的研究进展

封装材料是LED器件封装的重要组成部分,是目前各国学者们研究的热点,是影响LED器件的出光效率和使用寿命的关键材料。论述了功率型LED封装材料的作用及性能要求,并对国内外LED封装材料存在的问题和研究现状进行了介绍,重点是对有机硅封装材料的研究现状进行了全面论述。     

瓦克新的照明工业用有机硅封装材料简介

正新的照明工业用有机硅封装材料(如LUMISIL~?590591、LUMISIL~?740770和LUMISIL~?LR7601)是瓦克为LED(初级光学器件)封装、光学透镜及耦合元件(次级光学器件)生产而开发的新产品。LUMISIL~?590591是高透明的加成交联型LED有机硅封装材料,可固化成折射率为1.53的弹性体,属高折射率(HRI)封装材料,故其光输出量也极为理想。这些高透明有机硅还能让可见光(波长400~700 nm)几乎完全通过,在辐射强度高的情况下也不会黄变。此     

LED封装用聚合物材料研究进展

发光二极管(LED)是一类可直接将电能转化为可见光和热等辐射能的发光器件.随着亮度和功率的不断提高,封装材料成为制约LED进入照明领域的关键技术之一.本文综述了LED封装用聚合物材料的性能要求,并总结了近年来广泛使用的改性环氧树脂封装材料和有机硅封装材料的研究进展.     

功率型LED封装材料的研究进展

指出了环氧树脂作为目前LED主流的封装材料性能的不足,分析了目前改性环氧树脂、有机硅改性环氧树脂、有机硅树脂等做为功率型LED封装材料的优点和局限。综述了国内外主流的环氧树脂、有机硅改性环氧树脂、有机硅树脂等封装材料的研究进展。展望了功率型LED封装材料的发展趋势。     

LED封装用高分子材料的研究进展

综述了国内外发光二极管（LED）封装用高分子材料的研究进展,包括环氧树脂、改性环氧树脂、有机硅树脂等,指出了今后功率型LED封装用高分子材料的研究方向,认为高性能有机硅树脂将成为高端LED封装材料的封装方向之一。     

LED封装用改性环氧树脂研究进展

传统的LED环氧树脂封装材料存在脆性大、耐冲击性差、容易老化、透光率低、折射率低等缺陷,限制了其在LED封装产业中的应用,通过环氧树脂改性可弥补其作为LED封装材料的缺陷。本文综述了近年来LED环氧树脂封装材料在高折射率、光稳定、抗黄变、有机硅改性方面的研究进展,并展望了LED改性环氧树脂封装材料的发展前景。     

LED用高折射率有机硅封装材料的应用与研究进展

介绍了LED(发光二极管)用有机硅和EP(环氧树脂)封装材料的优势和劣势,并综述了近年来国内外LED用高折射率有机硅封装材料的研究现状及应用情况。最后展望了LED用高折射率有机硅封装材料的发展方向和发展前景。     

Synthesis and characterization of a high refractive diglycidyl ether of thiodibenzenethiol epoxy resin

High refractive index of epoxy resins used as encapsulant in light-emitting diode (LED) is essential in improving the light extraction efficiency, reducing heat and prolonging the service life of LED packages. In this study, diglycidyl ether of thiodibenzenethiol (DGETDBT), an epoxy resin with high refractive index, was synthesized via a novel method and its chemical structure was characterized with Fourier-transform infrared (FTIR) spectrometer and ¹H NMR spectrometer. Using m-xylylenediamine (MXDA) as curing agent, the curing behavior of DGETDBT was studied by differential scanning calorimetry (DSC) and was compared with that of diglycidyl ether of bisphenol A (DGEBA), a generally used encapsulant in LED. The thermal behavior and optical performance of these two resins were investigated with thermogravimetric analyses, UV?CVis scanning spectrophotometer, and Abbe refractometer, respectively. The results showed that DGETDBT/MXDA resin demonstrated similar curing and thermal behavior to DGEBA/MXDA resin. But its refractive index reaches 1.698, which is significantly higher than that of DGEBA/MXDA resin (1.604). Comparatively, DGETDBT resin can be expected to be a more effective encapsulant of LED.     

Effect of Glass Refractive Index on Light Extraction Efficiency of Light‐Emitting Diodes

Light‐emitting‐diode (LED) encapsulants, such as epoxy and silicone resin, have a lower refractive index than YAG:Ce phosphor, and this is usually one of the major causes of LED inefficiency. To improve LED performance, a glass encapsulant is considered. In this study, the SiO₂–B₂O₃–ZnO glass system containing La₂O₃ and WO₃ was investigated as an encapsulant to minimize total internal reflection and to increase the light extraction efficiency of LED packages. The characterization of glass encapsulants was performed using a differential scanning calorimeter, a pycnometer, a prism coupler, X‐ray photoelectron spectroscopy, and integrating spheres. The refractive index increased linearly with increasing molar volume of glass because La₂O₃ and WO₃ act as modifiers in the glass, creating more nonbridging oxygen. The refractive index of glass increases with the content of La₂O₃ and WO₃, which is attributed to the increase in polarizability of oxide ions in the glass. When the refractive index between glass and phosphor matched, light extraction efficiency was maximized because total internal reflection decreased.     

Transparent dispensible high‐refractive index ZrO2/epoxy nanocomposites for LED encapsulation

In this study, we report a facile ex situ approach to preparing transparent dispensible high‐refractive index ZrO₂/epoxy nanocomposites for LED encapsulation. Highly crystalline, near monodisperse ZrO₂ nanoparticles (NPs) were synthesized by a nonaqueous approach using benzyl alcohol as the coordinating solvent. The synthesized particles were then modified by (3‐glycidyloxypropyl)trimethoxysilane (GMS) ligand. It was found that, with tiny amount of surface‐treating ligand, the modified ZrO₂ NPs were able to be easily dispersed in a commercial epoxy matrix because of the epoxy compatible surface chemistry design as well as the small matrix molecular weight favoring mixing. Transparent thick (1 mm) ZrO₂/epoxy nanocomposites with a particle core content as high as 50 wt % and an optical transparency of 90% in the visible light range were successfully prepared. The refractive index of the prepared composites increased from 1.51 for neat epoxy to 1.65 for 50 wt % (20 vol %) ZrO₂ loading and maintained the same high‐Abbe number as the neat epoxy matrix. Compared with the neat epoxy encapsulant, an increase of 13.2% in light output power of red LEDs was achieved with the 50 wt % ZrO₂/epoxy nanocomposite as the novel encapsulant material. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3785–3793, 2013     

LED封装用甲基苯基含氢硅油的制备

以甲基苯基环四硅氧烷（D4^ph）为单体,含氢双封头（MMH）为封端剂,酸性阳离子交换树脂为催化剂,通过开环聚合的方法制备了LED封装用甲基苯基含氢硅油。研究了反应温度、反应时间对含氢硅油黏度的影响,及甲基苯基环四硅氧烷含量对含氢硅油折射率和黏度的影响。进行了^1H—NMR、红外光谱性能表征。结果表明,反应温度、反应时间能显著影响硅油的黏度;苯基摩尔分数越高,折射率也越大。最佳反应温度110℃,反应时间10h。以此方法合成的含氢硅油为主要原料,制备了折射率1．54,透光率95％的LED灌封胶,适合用于LED封装。     

Thermal resistance of cycloaliphatic epoxy hybrimer based on sol‐gel derived oligosiloxane for LED encapsulation

Cycloaliphatic epoxy hybrimer bulk was successfully fabricated by thermal curing of cycloaliphatic epoxy oligosiloxane resin synthesized by a sol‐gel condensation reaction with methylhexahydrophthalic anhydride (MHHPA) and tetrabutylphosphonium methanesulfonate (TBPM). The composition of MHHPA and TBPM in the resin was optimized to minimize yellowness of the cycloaliphatic epoxy hybrimer bulk. The sample with the optimized composition showed little discoloration upon thermal aging at 120°C for 360 h under an air atmosphere. On the basis of its high thermal stability with appropriate hardness and a high refractive index of 1.55, cycloaliphatic epoxy hybrimer bulk can be used as a LED encapsulant for white LEDs. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

高折射率LED封装胶耐高低温冲击性的研究

以苯基乙烯基硅树脂、苯基乙烯基硅油、含氢硅油、增粘剂等为原料,制成了双组分加成型高折射率LED封装胶。研究了原料对其耐高低温冲击性能的影响。结果表明：在苯基乙烯基硅树脂中引入5％的γ-环氧丙氧基丙基三甲氧基硅烷、配胶时将黏度为5000mPa·s和300mPa·S的苯基乙烯基硅油按10：2的质量比混合使用、交联剂采用活性氢质量分数为0．43％的苯基含氢硅油、增粘剂含环氧基和氢基的预聚物的质量分数为1％,按此配方配成的LED封装胶用于5050、5730灯架进行测试,完全固化后先过3次回流焊,然后在-40-＋100℃的冷热冲击测试试验机中进行测试,经过500个循环后,封装胶无裂胶、胶脱底和胶片脱落、死灯等现象。     

High refractive index thermally stable phenoxyphenyl and phenylthiophenyl silicones for light‐emitting diode applications

Creating high refractive index (RI) thermally stable polymers for encapsulating high‐brightness light‐emitting diodes (LEDs) remains a challenge and is an opportunity for improving LED efficiencies. The best previously reported RI for a 200°C heat stable encapsulant for LEDs is 1.56. Here, we report the use of novel phenoxyphenyl and phenylthiophenyl silicone monomers to give fully formulated encapsulants with RIs above 1.60. These liquid dispensed encapsulants are highly heat stable, showing little change in optical properties after heat aging at 200°C in air for seven weeks, and were also little changed after cycling between ?10°C to 85°C over 6 months. Phenoxyphenyl(phenyl) dimethoxysilane and phenylthiophenyl(phenyl) dimethoxysilane monomers were prepared via Grignard reactions. The resulting monomers were copolymerized with commercial silicone monomers and incorporated into hydrosilation‐based thermosets designed for use as LED encapsulants. RIs for the cured polymers were 1.60 at 633 nm (1.62 at 450 nm) for the phenoxyphenyl ether system and 1.62 at 633 nm (1.65 at 450 nm) for the phenylthiophenyl ether system. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39824.     

氢氧化铝对导热加成型有机硅灌封胶性能的影响

以粘度为300和1 000 mPa·s的端乙烯基硅油复配,含氢硅油为交联剂,三氧化二铝为导热填料,氢氧化铝[Al(OH)_3]为阻燃剂,制备了无卤阻燃导热加成型有机硅灌封胶,研究Al(OH)_3用量对导热加成型有机硅灌封胶性能的影响。结果表明:随着Al(OH)_3用量的增大,加成型有机硅灌封胶的阻燃性能和导热性能提高,粘度增大,体积电阻率和物理性能下降;当Al(OH)_3用量为60份时,加成型有机硅灌封胶的综合性能最佳。     

粉末NBR和超细碳酸钙填充粉末NBR硫化胶力学性能的研究*

以高分子树脂膜为包覆剂,采用凝聚共沉法制备非填充型粉末ＮＢＲ和超细碳酸钙填充粉末ＮＢＲ。研究了包覆剂及超细碳酸钙的用量对产物粒径及其硫化胶力学性能的影响。结果表明,当包覆剂用量为１０份时,粒径≤０９ｍｍ的产物占９９８％,加入超细碳酸钙后可进一步减小产物的粒径;极性适宜的包覆剂及超细碳酸钙对粉末ＮＢＲ硫化胶有显著的补强作用,故非填充型粉末ＮＢＲ及超细碳酸钙填充粉末ＮＢＲ均有良好的力学性能。扫描电镜分析表明,极性适宜的包覆剂与ＮＢＲ有一定的相容性,并以粒径约０５μｍ的微粒均匀分布于ＮＢＲ基体中;超细碳酸钙则以原生粒子和粒径≤０５μｍ的团粒存在,它在粉末ＮＢＲ中的分散性比块状ＮＢＲ／超细碳酸钙混炼体系有显著改善