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In this paper, the main failure modes and mechanisms were investigated through some failure analysis cases, based on this, Subsequent 160°C, 170°C and180°C lifetime tests were completed. According to the method of least squares, the degradation model of high power light emitting diodes is obtained. Using the model and ALTA9 software, the extrapolated lifetime of high power light emitting diode at...
In this paper, the main failure modes and mechanisms were investigated through some failure analysis cases, based on this, Subsequent 160°C, 170°C and180°C lifetime tests were completed. According to the method of least squares, the degradation model of high power light emitting diodes is obtained. Using the model and ALTA9 software, the extrapolated lifetime of high power light emitting diode at...
Different materials and thickness of die-attach layers can directly affect the heat dissipation of LED devices, so the influencing mechanism of interconnect materials and thickness to the thermal performances and optical durability were studied respectively. In the experiments, chip-on-board LED devices interconnected by gold-tin(Au80Sn20), solder paste and silver paste were prepared and evaluated...
Impact behaviors of high-power LED are essential due to the possible poor adhesion of interfaces and should be studied. In this study, the analysis of dynamic response for high-power LED module under impact load is conducted with simplified theoretical analysis, experimental testing and numerical simulation. A self-made microelectronics drop impact tester is established. Then reliability performances...
High power electronic devices create hot spots, which give rise to the junction temperature significantly higher than the ambient temperature. This induces a situation that the moisture diffusion from environment to device is in the direction against temperature gradient direction. In addition, far field relative humidity is different from the environment surrounding the packaged devices. In this...
In- and out-doors LED is a new device with excellent performance in power-saving, lighting efficiency, reaction time. Currently, it is widely used in communication, display, illumination. Reliability is a key point to promote its application. The most important reliability issue in LED modules is about packaging which includes refrigeration, bonding wire, the aging of organic material, good packaging...
Light-emitting diodes (LEDS) are a strong candidate for the nest-generation general illumination applications. The reliability of LEDs is the key point for its applications, and the main challenges facing the development of high reliable LED is packaging process. In this paper, the overview of state of the art techniques in LED failure analysis is provided, and the main failure modes such as bonding...
In this paper the reliability of high power LED street lamp subjected to temperature cycle is analyzed. Two kinds of finite element models of LED street lamp structure with 60W input power are established by using ANSYS software. The temperature cycling condition from −5°Cto 50°C is loaded. The increasing and decreasing rate of temperature is 5°C / min and the holding time is 30 minutes. This process...
Thermal characteristics of AlGaInP thin-film LED with transparent conducting ITO p-type contact by electrical method are presented and discussed. Samples without ITO fabricated from the same AlGaInP /GaAs epitaxial material are also prepared as references. The temperature coefficients of the samples are measured firstly and they are used as temperature sensitive parameters to determine the temperature...
According to Solid-State Lighting Manufacturing Roadmap 2009, lower cost and higher reliability are two key necessities for LED lighting. In this paper, an optimization process of thermal design for LED lighting system is carried out from the perspective of system in packaging. Based on the three-dimensional thermo-mechanical model of LED lighting system, the thermal and mechanical performance of...
To analyze the effect of moisture on the reliability of LED modules, diffusivity of packaging materials must be provided. Polycarbonate (PC) is an important material for LED lens. Its diffusivity measurement is usually based on the solution of one-dimensional diffusion. In this paper, the diffusivity measurement of PC was conducted. Simulation and analytical close-form solution (CFS) were also used...
Heat dissipation for packaging high-power light-emitting diodes is critically important to performance and reliability of LED lighting modules. The first thermal interface encountered by the heat flow is a die-attach material between the diode chip and its substrate. In this study, three different types of die-attach materials were used to construct 1-Watt GaN LED single-chip modules: a silver epoxy...
Reliability is one of primarily considered problems in white LED application. In this presentation, main failure modes in white LEDs such as ohmic contact degradation, electrode bonding defect, thermal mismatch and degradation of the encapsulation material, as well as ESD damage were analyzed, also combination with many failure analysis practices. Finally, several reliability assurance measures were...
Package is a key factor, and affects the reliability of LED. In this paper, the main failure modes and mechanisms that caused by poor package process were investigated through some failure analysis cases, and some improving methods to improve the LED's reliability are put forward.
This paper investigates the manufacturing variation in an Opto-BGA system in package (SIP) and its impact to the reliability and quality. Both the 3D finite element analysis (FEA) modeling and the reliability TMCL test on the opto-BGA manufacturing variation are studied. In the FEA model, the hyper-elastic behavior of the opto-coupling material is considered. In the reliability test, the samples are...
Reliability is one of the important problems in electronic packaging, which affects the use and life of the products. In this paper, we present a high power SiC-based light-emitting diode (LED), the thermal, mechanical and optical performances were investigated respectively. Heat dissipation performance and junction temperature were obtained using finite element analysis (FEA), the influences were...
White color LED has been investigated for lighting application with a big expectation of growth. And in terms of packaging of them in general, clear transparent epoxy resin has been mainly used in spite of problems such as coloring of the resin due to high temperature and UV light emitted from Chip itself. In order to solve this problem, we have investigated new materials such as silicon resin and...
Aiming to study dynamic mechanical properties of the transparent silicone resins for LEDs packaging and the effects of dynamic mechanical properties on the reliability of high power LEDs, dynamic mechanical analysis (DMA) has been adopted to study one silicone resin used for packaging high power white light LEDs. The viscoelastic behavior of silicone resin was obtained from multi-frequencies dynamic...
Atmospheric correction of Hyperion imagery over aquatic environments is generally more demanding than over land because the signal from the water column is small. In this paper, an atmospheric correction algorithm designed for the Hyperion hyper spectral imagery based on the analysis of the atmospheric correction algorithm of FLAASH and the algorithm adopted by MODIS imagery. It makes use of band...
The present work aims at studying the cooling performance of a thermoelectric device that integrated with integrated heat spreader (IHS) on a flip-chip plastic ball grid array (FC-PBGA) package. The new thermoelectric device herein is fabricated on the metal substrates by flip-chip assembly process. Thermal performance of the new package was comprehensive studied. The thermal resistances of IHS with/without...
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