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THERMAL RELIABILITY OF LOW-COST HIGH-POWER led PACKAGE module UNDER WHTOL TEST

ASME InterPack Conference

作者： Chen, C. H. Tsai, W. L. Tang, C. Y. Tsai, M. Y. Chang Gung Univ Dept Mech Engn Tao Yuan 333 Taiwan

ISBN: (纸本)9780791843598

The led issues, associated with high cost, high junction temperature, low luminous efficiency, and low reliability, have to be solved before gaining more market penetration. With special features of low-junction-temperature and low-cost design, COP (Chip-on-Plate) led package modules with and without phosphors are evaluated in terms of their thermal resistance and reliability under wet high temperature operation life (WHTOL) test. The WHTOL test is with the condition of 85 degrees C/85%RH and 350mA of forward current for 1008 hrs, specified in JESD22 Method A101-B. First of all, the thermal behaviors of the COP package module are investigated by experimental measurement, and a computational fluid dynamics approach. The reliability under WHTOL test is then carried out. The results show that all COP package modules with phosphors in the silicone encapsulant failed after 309 hrs at WHTOL test, but all those without phosphors passed for 1008 hrs. The failure sites are located at aluminum wire debonding to the chip and copper pads of the substrate. However, the aluminum wire bonding of the COP package modules are replaced to gold wire bonding, then all COP package modules with and without phosphors pass for 1008 hrs. For the passing package modules, their thermal resistances are found to increase more than two fold after 1008 hrs of the WHTOL test from 41 degrees C/W to 87.1 degrees C/W. This is due to the thermal conductivity decreasing in the die attach and thermal grease and the contact resistance increasing after the moisture absorption. Moreover, for the thermal behavior of the COP package modules under the natural and forced convections in the WHTOL test, the results show that there exists the difference of 17 degrees C/W in the junction-to-air thermal resistances, which might result in different reliability data. In addition, it is also indicated that the junction-to-air thermal resistances are very sensitive to the flow conditions of the chamber, but not for junc

关键词： led module thermal humidity reliability thermal resistance junction temperature

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Thermal analysis of remote phosphor in led modules

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Journal of Semiconductors 2013年第5期34卷 38-40页

作者：董明智韦嘉叶怀宇袁长安张国旗 Beijing Research Centre Delft University of Technology DIMES Delft University of TechnologyFeldmannweg 172628 CTDelftthe Netherlands State Key Laboratory of Solid State Lighting Research and Development Center for Semiconductor Lighting Institute of SemiconductorsChinese Academy of Sciences

Phosphor plays an important role in led packages by converting the wavelength of light and achieving specific color. The property and degradation of phosphor are strongly affected by the temperature. Some structural factors have been investigated in this paper and their effects are evaluated. Remote phosphor is an effective approach to improve the performance and reliability of led modules and products. It is a trade-off that the final product design depends on both the thermal performance and the cost.

关键词： led module remote phosphor thermal management

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Effects of Diode Voltage and Thermal Resistance on the Performance of Multichip led modules

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IEEE TRANSACTIONS ON ELECTRON DEVICES 2016年第1期63卷 390-393页

作者： Wang, Chien-Ping Chung Yuan Christian Univ Dept Mech Engn Taoyuan 32023 Taiwan

This paper investigated the thermal characteristics of multichip led modules under varying chip distances, driving currents, and number of chips in both parallel and series connections. The experimental results showed that, under the same input power, the thermal resistance and junction temperature were higher in series than in parallel due to the different diode resistances of individual chips. The deviations increase with increasing input power. Diode resistance variations significantly affected the current distributions in led modules due to the restricted constant forward voltage in parallel connections. Nonlinear incremental increases in thermal resistance also enhanced the temperature nonuniformity in the led module with increasing driving current. The theoretical approach substantially underestimates the junction temperature for two-chip and four-chip modules in both parallel and series connections, especially when the input power is high. The results are helpful for designing high-performance and long-term reliability multichip led lighting modules.

关键词： Junction temperature led module thermal resistance

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Research on test method of thermal resistance and junction temperature for led modules 17

Research on test method of thermal resistance and junction t...

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17th International Conference on Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems (EuroSimE)

作者： Liu, Dongyue Ru, Zhiqin Liu, Fang Zhang, Chenzhao Huang, Jie Hebei Semicond Res Inst Shijiazhuang Hebei Province Peoples R China

ISBN: (纸本)9781509021062

Until now, there has not yet been a standardized method for the led module thermal resistance measurements. This directly affects the lifetime assessment of the led modules. By testing and studying the temperature coefficient of the led modules with different structures, it is found that the temperature coefficient of the led module follows a linear relationship with voltage when an appropriate test current is applied. In this paper, we investigate the feasibility of measuring the thermal resistance of the led module as a whole. Furthermore, we propose a method to estimate the junction temperature of the led module based on the thermal resistances of each of its individual led and the module itself This method provides an important basis for the junction temperature calculation in the assessment of the lifetimes of the led module. However, since the led module usually has a large surface, the uncertainties existing in the materials and fabricating process will result in a distributed temperature within the led module. And in most cases, the first failure occurs in the chip with the highest junction temperature. Therefore, the next step of our research will focus on the evaluation of the maximum junction temperature of the led module based on the proposed method.

关键词： led module thermal resistance junction temperature measurement

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The Working Characteristics of Two-Phase Heat Transfer Devices for led modules

The Working Characteristics of Two-Phase Heat Transfer Devic...

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International Conference on Electronics and Information Technology (EIT)

作者： Kozak, D. V. Nikolaenko, Yu. E. Natl Tech Univ Ukraine Kiev Polytech Inst Heat Power Dept Kiev Ukraine

ISBN: (纸本)9781509022267

To cool the high-power light emitting diode modules (ledM) in lighting device it is promising to use two-phase heat transfer devices (TPHTD) - thermosyphons (TS) and heat pipes (HP), the equivalent thermal conductivity of which is hundreds of times greater than the thermal conductivity of metals. To this end, it is the most effective to use TPHTD as led chandelier frame elements. The paper presents the results of experimental studies of thermal resistance and heating zone temperature in the two-phase thermosyphon with a smooth evaporation surface and in the gravitational heat pipe with thread-capillary structure in the evaporation zone, filled with freone 141b, under conditions of condensation zone cooling by natural air convection.

关键词： led module lighting device thermosyphon heat pipe thread-capillary structure thermal characteristics freone 141b

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Modelling thermal properties of large led modules

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MATERIALS SCIENCE-POLAND 2019年第4期37卷 628-638页

作者： Ptak, Przemyslaw Gorecki, Krzysztof Dziurdzia, Barbara Gdynia Maritime Univ Dept Marine Elect Gdynia Poland AGH Univ Sci & Technol Dept Elect Krakow Poland

In this paper a problem of modelling thermal properties of large led modules is considered. The compact thermal model of such modules is proposed. The form of this model is presented and a method of parameters estimation is described. The practical usefulness of this model is verified experimentally by comparing the results of calculations and measurements of internal temperature of selected leds included in led modules. The modules were fabricated by Fideltronic, Poland and measurements of temperature distribution on the surface of the modules at selected variants of power dissipation were performed at the Gdynia Maritime University. Good agreement between the results of measurements and modelling was obtained.

关键词： led module compact thermal model computations measurements

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Machine Vision System for Automatic Adjustment of Optical Components in led modules for Automotive Lighting

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SENSORS 2023年第21期23卷 8988页

作者： Martinez, Silvia Satorres Gila, Diego Manuel Martinez Rico, Sergio Illana Camacho, Daniel Teba Univ Jaen Elect & Automat Engn Dept Robot Automat & Comp Vis Grp Jaen 23071 Spain Valeo Lighting Syst Jaen 23600 Spain

This paper presents a machine vision system that performs the automatic positioning of optical components in led modules of automotive headlamps. The automatic adjustment of the module is a process of great interest at the industrial level, as it allows us to reduce reworks, increasing the company profits. We propose a machine vision system with a flexible hardware-software structure that allows it to adapt to a wide range of led modules. Its hardware is composed of image-capturing devices, which enable us to obtain the led module light pattern, and mechanisms for manipulating and holding the module to be adjusted. Its software design follows a component-based approach which allows us to increase the reusage of the code, decreasing the time required for configuring any type of led module. To assess the efficiency and robustness of the industrial system, a series of tests, using three commercial models of led modules, have been performed. In all cases, the automatically adjusted led modules followed the ECE R112 regulation for automotive lighting.

关键词： machine vision automatic adjustment led module headlamp automotive lighting

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Separation and recovery of materials from the waste light emitting diode (led) modules by solvent method

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JOURNAL OF MATERIAL CYCLES AND WASTE MANAGEMENT 2020年第4期22卷 1184-1195页

作者： Zhu, Ping Ma, Yi Wang, Yangjun Yang, Yazheng Qian, Guangren Shanghai Univ Sch Environm & Chem Engn 99 Shangda Rd Shanghai 200444 Peoples R China Shangluo Univ Shaanxi Key Lab Comprehens Utilizat Tailings Reso Shangluo 726000 Peoples R China

Nowadays, a large quantity of Light Emitting Diodes (leds) have been produced and updated with the development of optoelectronic industry. At the same time, many waste leds are discarded. However, there are many metals and non-metals in waste leds, which may cause secondary pollution and waste of resources if disposed improperly. In this study, solvent method was used to dissociate the waste led modules and recycle resources. Firstly, the components of the waste led modules were analyzed. The main component of the transparent plastic part, usually used as packaging materials, is cured epoxy resin, and the main component of the white plastic part as the skeleton of led modules is a mixture of polyphenylene oxide (PPO) and polystyrene (PS). Then, eight organic solvents, [EMIM+]BF4- ion liquid and sodium hydroxide (NaOH) inorganic reagent were tried to separate a 40 x 40 mm(2) waste led module respectively. The results showed that only three organic solvents-dimethylformamide (DMF), dimethylacetamide (DMA), dimethyl-sulfoxide (DMSO) could dissociate the waste led module very well. The used DMF solution was purified by rotary evaporation, and the regenerative DMF solution could be reused because its property has not changed. The solid residue obtained after rotary evaporating DMF was identified as polystyrene (PS). It was inferred that the waste led module was dissociated through the DMF dissolving the PS of white plastic. In addition, the effect of DMF, DMA and DMSO dissociating the waste led modules with the change of temperature was discussed. It was found that the choice of suitable solvent is a key for this method, and the heating temperature was also a very important factor. Finally, it was measured that the cured epoxy resin and the white plastic of the waste led module accounted for about 31.4% (w/w) and 37.7% (w/w) respectively, which can be recycled. In short, the method not only separated completely the waste led module and its each part was recycled easily,

关键词： led module Organic solvent DMF

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System in package (SiP) technology: fundamentals, design and applications

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MICROELECTRONICS INTERNATIONAL 2018年第4期35卷 231-243页

作者： Santagata, Fabio Sun, Jianwen Iervolino, Elina Yu, Hongyu Wang, Fei Zhang, Guoqi Sarro, P. M. Zhang, Guoyi Peking Univ Dongguan Inst Optoelect Beijing Peoples R China Guangdong Dongguan Qual Supervis Testing Ctr Dongguan Peoples R China Beijing Delft Inst Intelligent Sci & Technol Beijing Peoples R China Southern Univ Sci & Technol Dept Elect & Elect Engn Shenzhen Peoples R China Delft Univ Technol Delft Inst Microsyst & Nanoelect Dimes Delft Netherlands Peking Univ Dongguan Beijing Peoples R China

Purpose - The purpose of this paper is to demonstrate a novel 3D system-in-package (SiP) approach. This new packaging approach is based on stacked silicon submount technology. As demonstrators, a smart lighting module and a sensor systems were successfully developed by using the fabrication and assembly process described in this paper. Design/methodology/approach - The stacked module consists of multiple layers of silicon submounts which can be designed and fabricated in parallel. The 3D stacking design offers higher silicon efficiency and miniaturized package form factor. This platform consists of silicon submount design and fabrication, module packaging, system assembling and testing and analyzing. Findings - In this paper, a smart light emitting diode system and sensor system will be described based on stacked silicon submount and 3D SiP technology. The integrated smart lighting module meets the optical requirements of general lighting applications. The developed SiP design is also implemented into the miniaturization of particular matter sensors and gas sensor detection system. Originality/value - SiP has great potential of integrating multiple components into a single compact package, which has potential implementation in intelligent applications.

关键词： Gas sensor system led module PM sensor System-in-package (SiP)

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Využití led technologie pro osvětlení městského mobiliáře

Využití LED technologie pro osvětlení městského mobili...

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作者： Bartoň, Luboš Brno University of Technology

Tato bakalářská práce se zabývá konstrukčním návrhem svítidla pro exteriérová schodiště. V konstrukci budou použity vysoce svítivé led diody. Bakalářsk... 详细信息

Tato bakalářská práce se zabývá konstrukčním návrhem svítidla pro exteriérová schodiště. V konstrukci budou použity vysoce svítivé led diody. Bakalářská práce dále zahrnuje rešerši z oblasti využití led diod, konstrukční řešení mého návrhu, počítačovou simulaci osvětlení schodiště a výkresovou dokumentaci.

关键词： led dioda led modul svítidlo schodiště led diode led module lamp stair Text

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