852 resultados para nurse-led


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对功率型倒装结构发光二极管(LED)温度场分布进行了有限元模拟,与实测结果进行了比较,并结合传热学基本原理对模拟结果进行了分析。结果表明,凸点的形状及分布与芯片内部温差有着密切的关系,蓝宝石的厚度对芯片内部温差也有一定的影响。同时,对倒装结构与正装结构的热阻进行了比较。

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介绍了几种常用的GaN基大功率白光发光二极管(LED)静电保护的方法,分析了GaN基大功率白光LED静电损伤的机理,并在此基础上,提出了改善GaN基大功率白光LED的抗静电损伤的途径与方法。

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三基色LED背光源是成就高品质液晶显示器的关键技术之一,其色域是传统CCFL背光源的150%以上。其中直下式背光源具有结构简单、光利用率高的特点,是目前大尺寸液晶显示背光源的首选,但是由于没有导光板,直下式背光源的光均匀性变得较差。通过对LED光场分布的模拟和分析,得出了一种新型LED光场分布设计,对由此光场分布的三基色LED组成的66cm(26in)背光源模拟表明,该背光源在未加扩散膜前,灯箱厚度为20~28mm时,亮度均匀度大于83%,△U’V’值在0.01左右;加上扩散膜之后,灯箱厚度为20mm时,均匀度可达到89.58%,△U’V’值达到0.0041。

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应用FDTD方法计算了二维无限大光子晶体的能带结构,并制备出了InP基二维平板结构的光子晶体器件.在制备过程中尝试了仅用PMMA做掩模以及PMMA和SiO2做掩模两种方法,结果表明,不使用SiO2做掩模的情况下,由于PMMA胶选择性较差,在刻蚀过程中难以保证图形的准确转移.而增加SiO2掩模后,获得了图形质量良好的光子晶体结构,成功实现了利用光子晶体结构增强LED的出光效率,与未制作光子晶体结构的LED相比,光子晶体结构LED的出光效率可在原来基础上提高1倍以上.并且随着晶格常数的增加,出光效率进一步提高。

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采用工业标准0.6μm CMOS工艺设计了以反向击穿硅p-n结为基础的光发射器件。讨论了该器件的光发射机理。利用商业模拟软件对器件的工作特性进行了模拟,包括器件的正向和反向I-V特性、p区掺杂浓度对击穿电压的影响以及门电压对器件发光强度的调制特性的影响等。结果表明该器件是一种很有前途的硅发光器件,在光互连等领域具有广阔的应用前景。

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氮化镓基蓝、绿光LED在光显示及未来的白光照明领域具有广阔的应用前景,中国科学院半导体研究所和深圳市方大国科光电技术公司利用双方各自的技术优势和资金管理优势,实现了氮化镓基蓝、绿光LED中游工艺技术产业化,目前产品已经批量上市销售。

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报道用自行研制的LP-MOVPE设备,在蓝宝石(α-Al_2O_3)衬底上生长出以InGaN为有源区的蓝光和绿光InGaN/AlGaN双异质结构以及InGaN/GaN量子阱结构的LED,其发射波长分别为430~450nm和520~540nm。

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于2010-11-23批量导入

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国家863计划

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The growth of wurtzite GaN by low-pressure metalorganic vapor-phase epitaxy on (1 1 1) magnesium aluminate (MgAl2O4) substrates have been studied. The morphological, crystalline, electrical and optical properties are investigated. A p-n junction GaN LED was fabricated on the MgAl2O4 substrate. (C) 1998 Elsevier Science B.V. All rights reserved.

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Some progress in the research of GaN based LED with photonic crystal structure has been made recently. Based on the photonic crystal's photonic band gap effect and photon grating diffraction principle, the extraction efficiency of LED with photonic crystal can be improved. In this paper, the restriction on AlGaInP LED's extraction efficiency is analyzed, and the photonic crystal is introduced in to the AlGaInP LED to improve the extraction efficiency. The theoretical analyses and the experiment results show that the output luminous intensity of LED with photonic crystal is improved by 16%, which results from some effect of the GaN based LED with photonic crystal.

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高速、大功率LED(≥3W)光源驱动电路是中子墙探测器光刻度系统的重要组成部分。本文简要介绍高速、大功率LED光源驱动电路的设计。该电路具有稳定性好、驱动脉冲前、后沿快,大电流脉冲输出等特点。内置信号源信号经过成形电路后,形成具有一定脉宽的快脉冲信号作为驱动信号,驱动信号上升时间tr<10 ns,下降时间tf<10 ns,其脉冲宽度分5档可调。该脉冲信号通过驱动电路控制输出电流开关,最大输出脉冲电流为800 mA,控制LED在额定功率下工作。该驱动电路最多可同时驱动六个大功率LED光源工作,目前已用于我所中子墙探测器阵列探测单元的初步刻度与测试。

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光刻度系统是中子墙探测器系统的重要组成部分,用于中子墙前端电子学的刻度和探测器工作性能变化的监测.通过对基于发光二极管(LED)作为光源的中子墙光刻度系统方案开展了细致的测试研究,确定了基于快脉冲驱动的大功率蓝光LED(3W)的中子墙光刻度系统方案,对中子墙探测单元进行了初步刻度测试,刻度结果能很好地满足光刻度要求,表明对于快塑料闪烁体探测器该方案是一种较为理想的方案.

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The light calibration system is one of the key components of Neutron Wall detector. It is used to calibrate the electronics and to monitor the long-term stability of the detector modules. With the detaile investigations, a calibration system with high-power LED (3W) driven by the fast pulses has been carried out. It is also tested together with the detector module of the Neutron Wall and the result of the preliminary calibration demonstrates that it fulfills the needs. It's a new design proposal to the light calibration system of the fast scintillator detector.