共查询到20条相似文献,搜索用时 140 毫秒
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《液晶与显示》2020,(9)
设计了用于发光二极管(LED)微显示器折射率匹配层结构,可以提高LED微显示器的光学性能。倒装结构的LED微显示器出光面为蓝宝石(折射率约1.76),它和空气的折射率(约为1.0)相差较大,会有很大一部分光因为全反射而反射回器件内部被吸收,导致器件的光效率降低。本文通过涂敷折射率匹配层硅胶(折射率约1.41~1.53)的方法,改变器件表层的折射率使其和空气的折射率相匹配,增加光逃逸锥角,从而提高器件的光效率。结果表明涂敷硅胶可以提高光效率约25.75%,在涂敷硅胶基础上盖玻璃片(折射率约1.47)可提高光效率约32.78%,且硅胶涂敷前后器件的电学、光学、结温稳定性好。尽管增加的是侧方向的光通量,但是其光效率的增加为高效率LED微显示的实现提供了参考依据。 相似文献
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多芯片阵列组合白光LED封装研究 总被引:2,自引:1,他引:1
文章阐述了LED器件的发光原理和芯片电极结构,围绕白光HB-LED的封装工艺,设计单个大功率芯片封装结构并对整个封装工艺进行研究,提出了多芯片阵列组合封装的创新理念,将其应用于多芯片阵列封装模块中。得出HB-LED封装中关键技术问题是提高外量子效率,采用高折射率硅胶减少折射率物理屏障带来的光子损失;采用高热导率的材料,减少由于封装工艺的缺陷带来的界面热阻。 相似文献
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大功率LED的发光强度大,产生的热量多,其产生的短波光辐射也比小功率发光二极管大,对LED封装材料提出了新的要求。综述了发光二极管封装用透镜胶的研究现状,根据发光二极管对高分子封装材料研发的要求,着重介绍了国内外为提高有机硅封装材料的导热性、耐热性、透光性以及耐紫外线辐射和关于材料折射率的调节方法等方面所做的最新研究成果和现状。对透镜胶研发过程中的重点和难点进行了分析,认为找到合适的填料和合适的方法把填料填入有机硅基体,或者在有机硅聚合物链上引入某些基团来改善封装材料的性能是研发的关键。 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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提高LED的光学和电学参数的测量精度与效率对于确保LED的产品质量、满足市场需求具有重要的意义.根据企业中LED的实际生产情况,给出了一种基于.NET平台的LED/板上芯片(COB)光电参数快速测量系统的软硬件设计方案.该系统通过可替换结构实现LED/COB多规格测量;通过与上层生产过程执行系统(MES)系统或企业资源规划(ERP)系统数据交互实现在线测量;通过设备各个独立运动部件的协同配合实现快速测量;通过光谱仪中线性电荷耦合元件(CCD)各个像素与LED波长的对应关系,实现了全光谱同时测量;通过对测量数据的处理,实现了基于LED光电和色度参数的自动分选.实验验证结果表明,系统能够有效提高LED光电参数测量的精度与效率. 相似文献
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The understanding of thermal resistance and junction temperature is important in the area of designing efficient, long-lasting high-power Light Emitting Diodes (LEDs) and diode stacks. This paper developed a systematic evaluating program for investigating the effect of location and thickness on the thermal resistance and junction temperature of LED on an aluminum substrate. Structure function measurements were implemented by Thermal Transient Tester (T3ster) and Integrating Sphere on LED placed on an aluminum plate. The temperature distribution of LED was analyzed to understand the relationship between thermal resistance and location of the LED on the aluminum base. Meantime, to evaluate the validity of the test, the simulation is developed by considering structure properties. The simulation curve basically has a similarity with the experimental curve in the overall. It implies that the evaluating method can provide guidance in understanding thermal reliability of LED lamps and designing thermal management techniques. 相似文献
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Failure modes and effects analysis for high-power GaN-based light-emitting diodes package technology
Ray-Hua Horng Re-Ching Lin Yi-Chen Chiang Bing-Han Chuang Hung-Lieh Hu Chen-Peng Hsu 《Microelectronics Reliability》2012,52(5):818-821
In this study, nondestructive test is developed to analyze the structure failure of LED package. The relationship between thermal resistance analysis and LED package failure structure is build with T3Ster thermal transient tester and scanning electron microscope (SEM). The failure LED device with defect in the attaching layer and gap between LED chip and copper are designed advisedly. The failure factors of LED package have been measured with thermal resistance analysis and SEM cross-section images. The thermal dissipation performance of LED with defect in the attaching layer is indicated by thermal resistance analysis combined with SEM cross-section images. The blister in attaching layer results in 4.4 K/W additional thermal resistance. The gap between LED chip and copper also makes high additional thermal resistance with 8.6 K/W. Different failures of LED packages are indicated obviously using thermal transfer analysis. The LED package failure structure such as interface defect between solder and cup-shaped copper is able to forecast without destructive measurement. 相似文献
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LED显示屏是近几十年来兴起的显示终端,作为媒体显示终端,高质量的图像显示是评价一个LED显示屏的重要因素.提出的一种灰度调制算法,为实际工程设计提供了最优控制参数选取方法,最大程度地利用资源和降低工程设计成本.文章首先构建了合理的屏体结构,讨论了各种设计参数之间的关系.文章中给出了信号时序的计算公式、每帧数据图像占用的时间、点亮效率和设计参数的约束关系、扫描时钟和设计参数的约束关系等,为设计者提供了有力的理论基础,对于不同要求的设计选择合理的参数,使得设计更加有理有据,更加完美,最后给出了以ARM单片机为核心控制系统设计的LED显示屏的方法步骤. 相似文献
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为了改善因为铟锡氧化物(ITO)薄层对紫外光具有高吸收率,从而导致石墨烯紫外LED低光提取效率(LEE)问题,采用ITO微纳结构(矩形和三角形)作为石墨烯紫外LED缓冲层的方法,利用时域有限差分法,对ITO微纳结构进行优化,并对石墨烯紫外LED进行了理论分析。结果表明,当矩形微纳结构厚度为160nm、占空比为0.7、周期为220nm时,在单层石墨烯下紫外LED的LEE可达10.668%;利用矩形微结构作为插入层相比于利用ITO薄层作为插入层的单层石墨烯紫外LED提高了45.06%;而当三角微纳结构在最优参量时,石墨烯紫外LED的LEE仅有6.64%,明显低于ITO薄层石墨紫外LED。该研究可为后续制备高光功率的紫外LED提供理论基础。 相似文献
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将功率循环方法应用于大功率LED焊料层的可靠性研究,对比分析了在650 mA,675 mA和700 mA电流条件下大功率LED焊料层的热阻退化情况。实验结果表明,循环达到一定次数,大功率LED热阻才开始退化,并呈线性增加,从而引起光通量下降;另外,失效循环次数与电流值之间呈线性关系,并外推出正常工作条件下焊料层寿命为90 968次。对样品进行了超声波检测(C-SAM),发现老化后LED焊料层有空洞形成,这说明空洞是引起热阻升高的主要原因。 相似文献
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Nitride-based cascade near white light-emitting diodes 总被引:5,自引:0,他引:5
Chen C.H. Chang S.J. Su Y.K. Sheu J.K. Chen J.F. Kuo C.H. Lin Y.C. 《Photonics Technology Letters, IEEE》2002,14(7):908-910
An InGaN-GaN blue light-emitting diode (LED) structure and an InGaN-GaN green LED structure were grown sequentially onto the same sapphire substrate so as to achieve a nitride-based near white LED. In order to avoid thyristor effect, we choose a large 2.1×2.1 mm2 LED chip size, which was six times larger than that of the normal LED. It was found that we could observe a near white light emission with Commission International de l'Eclairage color coordinates x=0.2 and y=0.3, when the injection current was lower than 200 mA. It was also found that the output power, luminous efficiency and color temperature of such a cascade near white LED were 4.2 mW, 81 l m/W, and 9000 K, respectively 相似文献