共查询到17条相似文献,搜索用时 156 毫秒
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热界面材料对高功率LED热阻的影响 总被引:2,自引:2,他引:0
散热不良是制约大功率LED发展的主要瓶颈之一, 直接影响着大高功率LED器件的寿 命、出光效率和可靠性等。本文采用T3ster热阻测试仪和 ANSYS热学模拟的方法对LED器件进行热学分析,以三种热界面材料(金锡,锡膏,银胶)对LE D热阻及芯片结温的影响为例,分析了热界面材料的热导率、厚度对LED器件热学性能的影响 ,实验结果表明界面热阻在LED器件总热阻中所占比重较大,是影响LED结温高低的主要因素 之一;热学模拟结果表明,界面材料的热导率、厚度及界面材料的有效接触率均会影响到LE D器件结温的变化,所以在LED器件界面互连的设计中,需要综合考虑以上三个关键参数的控 制,以实现散热性能最佳化。 相似文献
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大功率LED的热阻测量与结构分析 总被引:4,自引:1,他引:3
热阻的精确测量与器件结构分析是设计具有优良散热性能的大功率LED的前提。本文研究了大功率LED的光功率、环境温度和工作电流对热阻的影响规律,论述了积分式结构函数和微分式结构函数的推导过程及其主要性质,提出了大功率LED热阻的精确测量方法,并利用结构函数分析及辨识大功率LED器件的内部结构、尺寸、材料、制造缺陷和装配质量。 相似文献
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散热是大功率LED封装的关键技术之一,散热不良将严重影响LED器件的出光效率、亮度和可靠性。影响LED器件散热的因素很多,包括芯片结构、封装材料(热界面材料和散热基板)、封装结构与工艺等。文章具体分析了影响大功率LED热阻的各个因素,指出LED散热是一个系统概念,需要综合考虑各个环节的热阻,单纯降低某一热阻无法有效解决LED的散热难题。文中还对国内外降低LED热阻的最新技术进行了介绍。 相似文献
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SPRITE探测器的优化设计 总被引:1,自引:1,他引:0
本文在一维理论的基础上,经微处理机模拟计算,设计给出了工作在8—14μm波段SPRITE探测器的优化参数:器件长700μm,宽62.5μm,厚7μm,读出区长度50μm,工作偏压2.8V。结果表明,受器件粘接胶层热阻及扫出效应的影响,更大的器件工作偏压只能使器件优值参数探测率和调制传递函数交劣。计算结果还表明,尽可能减少器件在衬底上的粘接胶层厚度,背景辐射及材料的净掺杂浓度,有利于提高器件性能。 相似文献
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大功率白光LED的结温测量 总被引:1,自引:1,他引:0
大功率LED器件的结温是其热性能的重要指标之一,温度对LED的可靠性产生重要的影响。采用板上封装的方法,利用大功率芯片结合金属基板封装出了大功率白光LED样品,利用LED光强分布测试仪测试了器件的I—V曲线,用正向电压法测量了器件的温度敏感系数,进而通过测量与计算得到器件的结温和热阻。最后利用有限元对器件进行实体建模,获得了器件的温度场分布。测量结果表明:正向电压与结温有很好的线性关系,温度敏感系数为2mV·℃^-1,LED的结温为80℃,热阻为13℃·W^-1。有限元模拟的结果与实测值具有良好的一致性。 相似文献
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大功率LED封装界面材料的热分析 总被引:10,自引:0,他引:10
基于简单的大功率LED器件的封装结构,利用ANSYS有限元分析软件进行了热分析,比较了四种不同界面材料LED封装结构的温度场分布。同时对纳米银焊膏低温烧结和Sn63Pb37连接时的热应力分布进行了对比,得出纳米银焊膏低温烧结粘接有着更好的热机械性能。 相似文献
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HgCdTe芯片粘接可靠性设计 总被引:1,自引:1,他引:0
根据HgCdTe材料的特性和77K低温下工作的要求,结合目前研磨抛光的技术水平,从粘接机理和传热学等方面分析计算了粘接界面的最小接触高度、接触热阻和热应力,给出理想粘接界面的模型,介绍了胶层厚度对器件性能的影响,提出选择HgCdTe芯片粘接剂的主要依据和减小粘接界面接触热阻的技术途径。 相似文献
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高压(HX)倒装LED是一种新型的光源器件,在小尺寸、高功率密度发光光源领域有广泛的应用前景.设计了4种不同工作电压的高压倒装LED芯片,进行了流片验证,并对其进行了免封装芯片(PFC)结构的封装实验,在其基础上研制出一种基于高压倒装芯片的PFC-LED照明组件.建立了9V高压倒装LED芯片、PFC封装器件及照明组件的模型,利用流体力学分析软件进行了热学模拟和优化设计;利用T3Ster热阻测试分析仪进行了热阻测试,验证了设计的可行性.结果表明,基于9V高压倒装LED芯片的PFC封装器件的热阻约为0.342 K/W,远小于普通正装LED器件的热阻.实验结果为基于高压倒装LED芯片的封装及应用提供了热学设计依据. 相似文献
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D.A. van den Ende R.H.L. Kusters M. Cauwe A. van der Waal J. van den Brand 《Microelectronics Reliability》2013
Integration of LEDs on flexible foil substrates is of interest for flexible lighting applications and for backlights for flexible displays. Such a large area lighting device can be made by integrating a matrix of closely spaced LEDs on a flexible foil substrate. Preferably, these LEDs are integrated unpackaged, i.e. as bare dies, as this reduces footprint, thickness and cost. As substrates, low cost materials like polyethylene terephthalate (PET) should preferably be used. However, the use of these materials also imposes limitations. Especially, their low thermal stability limits the maximum temperatures during the processing and the thermal dissipation of the LED during operation will pose constraints on the thermal design. This paper describes the results of research on possibilities for integrating bare die LEDs with such low cost flexible PET foils. Bonding of LED dies on PET substrates with copper circuitry using conductive adhesives was performed. Both anisotropic conducting adhesives and isotropic conducting adhesives were investigated. An experimental comparison is made between the different techniques based on temperature/humidity reliability and flexural stability of the bonded LEDs. Additionally, finite element (FE) thermal modeling results of adhesively bonded LED-on-foil configurations are presented. The role of the different materials and the effect of their geometries on the temperature distribution in the simulated devices are discussed. The results are compared to experimentally observed temperature distributions using infrared thermal imaging in LED on PET foil reference devices. Finally a demonstrator device of 64 LEDs on flexible copper–PET substrate is presented. 相似文献
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The performance of high power LEDs strongly depends on the junction temperature. Operating at high junction temperature causes degradation of light intensity and lifetime. Therefore, proper thermal management is critical for LED packaging. While the design of the heat sink is a major contributor to lowering the overall thermal resistance of the packaged luminaire, another area of concern arises from the need to address the large heat fluxes that exist beneath the die. In this study we conduct a thermal analysis of high power LED packages implementing chip-on-board (COB) architecture combined with power electronic substrate focusing on heat spreading effect. An analytical thermal resistance model is presented for the LED array and validated by comparing it with finite element analysis (FEA) results. By using the analytical expression of thermal resistance, it is possible to understand the impact of design parameters (e.g., material properties, LED spacing, substrate thickness, etc.) on the package thermal resistance, bypassing the need for detailed computational simulations using FEA. 相似文献
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提出了一种新的LED灯具封装方式,使用高导热玻璃壳和惰性气体替代传统的环氧树脂进行封装,使用塑料散热器代替传统铝基板,以达到双通道散热的效果。采用ANSYS有限元热分析软件,优化惰性气体层厚度,并通过改变LED个数和单灯功率与传统的陶瓷基板COB封装方式进行热仿真对比分析。研究表明,惰性气体层厚度为1.5 mm时散热效果较好,双通道散热灯具的热阻远小于单通道散热灯具热阻。由于玻璃与传统的环氧树脂相比,透光性高、不易老化、抗紫外线效果好,在大功率、密集型封装和紫外LED灯具大发展的市场环境下,这种新的封装方式应用前景广阔。 相似文献
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Interfacial thermal resistance and temperature dependence of threeadhesives for electronic packaging
Hasselman D.P.H. Donaldson K.Y. Barlow F.D. Elshabini A.A. Schiroky G.H. Yaskoff J.P. Dietz R.L. 《Components and Packaging Technologies, IEEE Transactions on》2000,23(4):633-637
The thermal resistance and its temperature dependence was measured for three industrial adhesives used for electronic packaging. Measurements were made by the laser-flash method from room temperature to 300°C. The samples were in the form of sandwiches consisting of two platelets of silicon carbide-reinforced aluminum (AlSiC) bonded together with the adhesives. The total thermal resistance of the bond (the sum of the bulk thermal resistance of the adhesive and the resistances at the two interfaces) was calculated from the thermal response of the sandwich subjected on one side to a single laser-flash. The total thermal resistance was found to decrease with increasing temperature. The bulk thermal resistance of the adhesive, calculated from its thickness and independently determined thermal conductivity, was found to be relatively independent of temperature. The interfacial resistance at the AlSiC interfaces, depending on the adhesive, ranged from about 60 to 80% of the total resistance decreasing to about 50% of the total interfacial resistance at 300°C. For two of the adhesives considered in this study, the interfacial thermal resistances for the AlSiC/adhesive interfaces were found to be considerably higher than those found in an earlier study of Si/adhesive interfaces 相似文献
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This paper discusses, based on a practical example, the problem of power LED thermal modelling. The precise determination of thermal resistance is crucial for accurate computation of junction temperature, which influences both device lifetime and reliability as well as its operating parameters. Here, diode heating curves are recorded at different levels of dissipated power and in various cooling conditions. Moreover, the devices are soldered to the substrate in different ways, what renders possible the determination of their junction-to-case thermal resistances. For each case, an adequate compact thermal model is generated using the Network Identification by Deconvolution method and validated against the measurements. 相似文献