共查询到18条相似文献,搜索用时 140 毫秒
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COB封装对LED光学性能影响的研究 总被引:3,自引:2,他引:1
针对LED高光效、低功耗的要求,文章在分析LED光学性能的基础上,采用了COB(ChipOn Board)即板上芯片封装技术。研究了不同封装工艺和材料,分析比较其对LED光通量、光效和色温的影响。研究首先介绍COB封装的结构、优点及其实用性,然后分析影响LED光学性能的因素,最后进行测试。在实验过程中,发现COB封装结构除了具有保护芯片的功能外,还可以提高出光效率,并实现特定的光学分布。实验结果表明:文章提出的封装工艺对于提高光通量和光效、调节色温有良好的效果。 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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柔性基板封装(COF)是一种新型LED封装形式。本研究在柔性基板中的高分子绝缘层(PI)中添加全铜通孔,通过有限元仿真分析全铜通孔对LED封装热学性能的影响。研究结果表明:在柔性LED封装中,PI层热阻最大,是导致芯片结温高的主要因素。PI层中全铜通孔的添加使PI层热阻大幅降低,显著提升LED封装的垂直散热能力。基于仿真计算结果,建立了PI层中添加全铜通孔数量与LED封装热阻间的对应关系。针对本研究中的封装结构,采用8*8 的全铜通孔阵列对LED封装的热学性能提升效果显著。 相似文献
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COB白光LED的光提取效率研究 总被引:1,自引:0,他引:1
针对LED高光效、高显色指数的要求,在分析LED光学性能的基础上,采用板上芯片(COB,Chip on Board)技术研究了表面涂覆硅胶量对COB白光LED的光通量、光效、色温和显色指数的影响,并提出一种高光效、高显色指数、低色温的白光LED封装方案,提高了COB白光LED的出光效率,实现了特定的光学分布,最终实现14 W COB封装结构下的白光LED,在电流密度为30 A/cm2时,其色温、显色指数及光效分别为4 900 K、82和125 lm/W. 相似文献
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基于板上芯片(COB)封装技术,提出了一种360°出光的新型发光二极管(LED)灯丝球泡灯,其封装基板采用透明基板.研究了不同封装材料及芯片对其LED光通量、光效和色温的影响.首先介绍了LED灯丝球泡灯的结构、优点,然后分析了影响LED光学性能的因素,最后进行相关性能测试.测得采用玻璃/蓝宝石基板封装的LED灯丝的光通量分别为467.29和471.69 lm;光效分别为110.06和111.79lm/W;显色指数分别为84.1和81.9.测试结果表明,采用透明基板封装的LED灯丝球泡灯不仅能有效调节色温,而且能显著提高LED的光通量、光效和显色指数. 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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In this study, the heat dissipation efficiencies of high power multi-chip COB (Chip-on-Board) LEDs with five different chip gaps were compared by assessing their junction temperature (Tj) and thermal resistance (Rth). Junction temperatures were measured using an IR camera and were also simulated by computational fluid dynamics (CFD) software. The effects of heat sinks with different surface areas, heat slugs made of different materials and different injection currents (different wattages) on high power LED junction temperatures are discussed. In addition, the optical characteristics of the LED, such as its lumens and luminous efficiency are evaluated. The experimental results show that a chip with a smaller gap has a higher junction temperature and more thermal resistance, and the junction temperature difference between the LEDs with the smallest and largest chip gaps is 3.12 °C. Optical performance analyses show that the LED with a larger chip gap has higher lumens and higher luminous efficiency. Thus, higher junction temperatures reduce the optical performance of high power LEDs. 相似文献
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介绍了一种带有凹槽和硅通孔(through silicon via,TSV)的硅基制备以及晶圆级白光LED的封装方法。针对硅基大功率LED的封装结构建立了热传导模型,并通过有限元软件模拟分析了这种封装形式的散热效果。模拟结果显示,硅基封装满足LED芯片p-n结的温度要求。实验结合半导体制造工艺,在硅基板上完成了凹槽和通孔的制造,实现了LED芯片的有效封装。热阻测试仪测得硅基的热阻为1.068K/W。实验结果证明,这种方法有效实现了低热阻、低成本、高密度的LED芯片封装,是大功率LED封装发展的重要方向。 相似文献
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In this paper, the cost of a light emitting diode (LED) package is lowered by using a silicon substrate as the base attached to the chip, in contrast to the conventional chip-on-board (COB) package. In addition we proposed an LED package with a new structure to promote reliability and lifespan by maximizing heat dissipation from the chip. We designed an LED package combining the advantages of COB based on conventional metal printed circuit board (PCB) and the merits of a silicon sub-mount as a substrate. When an input current 500–1000 mA was applied, the fabricated LED exhibited the light output of approximately 112 lm/W at 29 W. We also measured and compared the thermal resistance of the sub-mount package and conventional COB package. The measured thermal resistance of the sub-mount package with a reflective film of Ag and the COB package were 0.625 K/W and 1.352 K/W, respectively. 相似文献
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The status and prospects for high-power, phosphor-based white light-emitting diode (LED) pack-aging have been presented. A system view for packaging design is proposed to address packaging issues. Four aspects of packaging are reviewed: optical control, thermal management, reliability and cost. Phosphor materials play the most important role in light extraction and color control. The conformal coating method improves the spatial color distribution (SCD) of LEDs. High refractive index (RI) encapsulants with high transmittance and modified surface morphology can enhance light extraction. Multi-phosphor-based packaging can realize the control of correlated color temperature (CCT) with high color rendering index (CRI). Effective thermal management can dissipate heat rapidly and reduce thermal stress caused by the mismatch of the coefficient of thermal expansion (CTE). Chip-on-board (COB) technology with a multi-layer ceramic substrate is the most promising method for high-power LED packaging. Low junction temperature will improve the reliability and provide longer life. Advanced processes, precise fabrication and careful operation are essential for high reliability LEDs. Cost is one of the biggest obstacles for the penetration of white LEDs into the market for general illumination products. Mass production in terms of CoB, system in packaging (SIP), 3D packaging and wafer level packaging (WLP) can reduce the cost significantly, especially when chip cost is lowered by using a large wafer size. 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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Study of Phosphor Thermal-Isolated Packaging Technologies for High-Power White Light-Emitting Diodes
Bingfeng Fan Hao Wu Yu Zhao Yulun Xian Gang Wang 《Photonics Technology Letters, IEEE》2007,19(15):1121-1123
A novel packaging configuration for high-power phosphor-converting white light-emitting diodes (LEDs) application is reported. In this packaging configuration, a thermal-isolated encapsulant layer was used to separate the phosphor coating layer from the LED chip and the submount. Experimental and finite-element method simulation results proved that this thermal management can prevent the heat of LED chip from transferring to the phosphor coating layer. The surface temperature of the phosphor coating layer is a 16.8degC lower than that of the conventional packaging at 500-mA driver current for 1-mm power GaN-based LED chip. Experimental results also show that this packaging configuration can improve the light-emitting power performance and color characteristics stability of the white LED, especially under high current operating condition. 相似文献
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