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发光二极管材料与器件的历史、现状和展望 总被引:23,自引:0,他引:23
文章介绍了发光二极管材料和器件的研究、开发的历史,概述了发光二极管技术的发展现状和进展.通过与其他类型光源的比较,向读者展示了发光二极管未来的重要地位和光明前景.发光二极管的最近的成就是实现了有色光方面的成功应用.高功率白色发光二极管已开始应用于便携式和特殊照明.而在通用的照明领域要成功地应用发光二极管,则需要通过性能和价格方面的继续突破来实现. 相似文献
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为了满足数字摄像法能见度测量仪均匀光源的要求,提高半导体发光二极管照明的均匀性,该文提出一种基于数字图像分析技术的设计方法。首先测量单颗LED在模组区域的亮度分布,进而拟合分布函数,再运用多颗LED亮度叠加原理,计算出不均匀度最小的多颗LED阵列方式,或固定均匀度对应的最佳尺寸。对仿真数据和实测数据进行对比分析,结果表明,该文计算出的LED阵列方式,与单边阵列相比,均匀度显著提高,最高可达95%以上。 相似文献
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Light emitting diode (LED) has more advantages compared with a traditional incandescent light bulb and a fluorescent lamp,
such as small size, low quantity of heat, long life, low power consumption, fast response, plain packaging and ease of develop
ment of a frivolous short product. A methodology is proposed to improve the uniformity of the LED illumination system. As
a light source in a backlight unit (BLU), the requirement for optical characteristics of a LED is different from highly directional
conventional ones. New diffused-type LEDs need to be developed to fulfill the requirement of the BLU industry. A non-spherical
lens is designed to optimize uniformity, and a great improvement in uniformity from 28.4 to 64% is demonstrated. In the future,
it may used in an LED display to improve the unevenness of illumination. 相似文献
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功率型发光二极管的研究与应用进展 总被引:3,自引:0,他引:3
文章首先对功率型发光二极管的起源和发展作了回顾和简要的叙述.然后以固体光源照明为目标,给出了几种可见光功率发光二极管芯片和封装的典型结构,并且对它们各自的特点进行了比较.最后指出了功率发光二极管作为固体光源取代真空灯泡用于照明在未来的五至十年内将成为现实. 相似文献
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为了提升氮化镓(GaN)蓝光发光二极管(LED)光提取效率, 设计了双层光子晶体LED模型. 提出等效折射率近似方法, 简化求解了结构中的介质波导模式分布. 从而对模型中顶层光子晶体刻蚀深度d, 嵌入式光子晶体厚度T及其距有源层距离D等结构参数进行了优化. 同时利用时域有限差分方法对优化结果进行了验证. 相比其他仿真方法, 模式分析极大地减少了对LED建模优化的计算复杂度, 同时从理论上阐明了不同结构参数变化引起LED光提取效率改变的原因. 研究发现, 当顶层光子晶体满足d ≈ λ / nPhCs 时, 结构内大部分高阶导模尚未被截断但源区能量向低阶导模的转化被有效抑制, 光提取效率给出极大值. 嵌入式光子晶体的引入将激发覆盖层模式, 当满足100 nm≤ T ≤ 300 nm且100 nm≤ D ≤ 200 nm 时, 覆盖层模式可以从有源层获得较大能量并有效地与顶层光子晶体耦合, 极大地提升了光提取效率. 本文优化结果使得LED光提取效率提升了4倍, 对高性能GaN蓝光LED的设计制造具有重要意义. 相似文献
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《Opto-Electronics Review》2019,27(4):355-362
In literature, it is known that a Light Emitting Diode (LED) could be used as a light sensor. It is also known that its emitted light spectrum and sensitivity spectrum can be partially overlapped. This work presents how commercial LEDs can be used as light emitters and simultaneously as sensors of the reflected portion of the light emitted by themselves. The realized devices present a unique characteristic: the transmitter and the receiver coincide spatially as they are the same device. This ensures the perfect overlapping between transmission and reception radiation lobes that could provide many benefits in several applications like as distance measurements or image sensors. Some simple electronic configurations that use LEDs as detectors of their own emitted light are presented. It has been also demonstrated how these LEDsTx-Rx can work as image sensors by acquiring an image of a simple test object, and how they can realize distance sensors with respect to other known techniques. Further advantages can be obtained by realizing LEDTx-Rx array in single integrated devices. With the realization of such devices, it will be also possible to experiment new constructive solutions for commonly used applications, without the need of using separate emitter and receiver. 相似文献
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提出了一种基于Lambert辐射模型的发光二极管光源阵列发射天线光照度计算模型,对室内可见光通信发射天线进行了优化设计.分析了光源的空间分布形式、光源间距、光源中心光束与系统光轴夹角以及空间分布层间距等因素对光照度均匀性的影响.通过仿真模拟和分析,得到了圆形阵列天线在照度均匀性和通信传输信号稳定性方面都优于相同光源数目的矩形阵列天线,并且提高了10%左右;同时得出了在满足室内照明情形下,发光二极管阵列发射天线照度均匀度随光源间距及光源中心光束与系统光轴夹角的增加均呈现出先增加后减小的变化趋势,因此,光源间距和光源中心光束与系统光轴夹角均存在最优值;照度均匀度随空间分布层间距的减小而增加,并给出了5 m×5 m×3 m普通房间内发射天线阵列设计参数的最优值,使发射性能得到了优化,同时节省光源数13%,降低了成本.这些研究为发射天线系统的设计提供了理论依据,具有实用价值. 相似文献
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Multi-objective design and extended optimization for developing a miniature light emitting diode pocket-sized projection display 总被引:1,自引:0,他引:1
This research proposes a new extended optimization method for a miniature light emitting diode (LED) pocket-sized projection
display, introducing integration of the Taguchi method and principal component analysis in order to optimize the multiple
quality characteristics of an LED pocket-sized projection display. With the aid of interactive optimization, control factors
with three different levels are carefully selected in the complicated preliminary experiments. A set of optimal design parameters
is well selected for best results on the combined effects of the total luminous flux, illumination uniformity, and the packing
size of the system. The selected control factors are inclusive of major lens and system specifications, such as lens overall
length, X-CUB semi-aperture, length of light integrator, width of integrator, total internal reflection (TIR) prism entering
semi-diameter for the TIR prism, air-gap of the TIR prism, and digital micromirror device (DMD) position; an L18 orthogonal
array is applied and implemented in the experiments. According to experimental results, the optimal design parameters for
the projection display can be determined as A1 (lens specifications: type I), B3 (lens length: overall length), C1 (X-CUB
semi-aperture: 8 mm), D3 (integrator length: 36.6 mm), E2 (integrator width: 3.5 mm), F2 (TIR prism entering semi-diameter:
11 mm), G1 (TIR prism air-gap: 1.0024 mm), and H1 (DMD location: −0:5 mm). In addition, analysis of variance (ANOVA) is also
employed to identify the factor A (lens specifications), factor D (integrator length), factor F (TIR prism entering semi-diameter),
and factor G (TIR prism air-gap) as key parameters, which account for 71.82% of the total variance. The other factors when
compared are found to have relatively weaker impacts on the process design. Furthermore, a confirmation experiment of the
optimal design parameters shows that the aforesaid multiple performance characteristics are optimized to achieve the best
levels. It is concluded that Taguchi method and principal component analysis (PCA) combine to optimize and then minimize the
LED pocket-sized projection display system, which not only yields a sufficient understanding of the effects of control factors,
but also produces an optimized design to ensure that the LED pocket-sized projection display system exhibits the best multiple
performance characteristics. 相似文献
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Modified wide radiating lenses of the power-chip light emitting diodes for a direct-lit backlight 总被引:1,自引:0,他引:1
Modified wide radiating lenses of the power-chip light emitting diodes (LEDs) for a direct-lit backlight unit of a liquid crystal display (LCD) are numerically investigated. To improve the optical properties of the backlight, the lens of the Golden DRAGON® ARGUS® LED, the cluster of LEDs, and the cluster arrangement for the 32-in bottom-lit backlight unit of a LCD are modified and verified by optical tracing simulation software. First, the central section shape is modified and analyzed to reduce the angular luminous intensity in the small angle range. The results show that the modifying lens method can effectively realize the aim. Then, several LEDs with the modified lenses are put in 32-in backlight. It is shown that the uniformity and efficiency of the new backlight are obviously better than the ones of the original type. 相似文献
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用高温固相反应法合成了Sr2EuxGd1-xAlO5红色荧光粉,研究了荧光粉的晶体结构和发光性质。在紫外光和近紫外光激发下,样品的发射光谱由Eu3+的5D0→7FJ(J=0,1,2,3,4) 特征发射组成,其中Eu3+离子的5D0→7F1(λ=590 nm)和5D0→7F2(λ=622 nm)跃迁发射的强度最大。当Eu3+离子的摩尔分数为 0.75时,样品的发光最强。研究结果表明,Sr2EuxGd1-xAlO5荧光粉是一种在近紫外芯片白光LED上有应用前景的红光荧光粉。 相似文献
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LED照明的光栅光调制器光学特性分析与实验 总被引:1,自引:1,他引:1
针对一种新型的光凋制器--光栅光调制器,研究用LED作为其照明光源时对光学调制特性的影响.以部分相干光理论为依据,结合MATLAB仿真,推导出用LED照明光栅光调制器时,光源带宽对成像对比度具有较大的影响,通过滤色片将光源带宽减小到13 nm时,像面上的对比度约为150,进一步减小带宽至10 nm,对比度将达到225.光源的尺寸在与光源到光栅光调制器之间的距离相比小于0.03时,对光栅光调制器的光学信息处理不会有影响,并通过实验加以证实,从而说明采用LED作为光栅光调制器照明光源的可行性. 相似文献
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提出用AlGaAs材料为n型下DBR,AlGaInP材料为p型上DBR,GaInP/AlGaInP多量子阱为有源区来制备650nm波长的共振腔发光二极管(RCLED).用传输矩阵法对器件的结构进行了理论设计,并制备了RCLED和普通LED两种结构.测试结果表明,RCLED有更高的发光效率,是普通LED的近1.3倍,当注入电流从3mA增加到30mA时,RCLED的峰值波长只变化了1nm,而普通LED的波长则变化了7nm,且RCLED的光谱半宽窄,远场发散角小.
关键词:
发光二极管
共振腔
金属有机物化学气相淀积 相似文献
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介绍了一种以发光二极管(LED)点光源作为相机标定光源的方法。根据LED点光源的特性,用恒流源给LED点光源提供所需的电流,用光照度计测量LED光源的光强度。由ARM单片下位机控制恒流源;通过串行通讯与上位机交换数据;由计算机作为上位机来管理数控恒流源和光照度计;根据所测光度值来调节电流,直到光度达到预想值。实验分析显示:LED点光源作为标定光源可以达到CCD标定的要求,精度也较高,能够很好地自适应控制LED的光照强度,达到了预期的效果,且系统使用方便灵活,性能稳定可靠。 相似文献
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An efficient flat-top illuminating optical system optimized for an extended light source is presented. The source is a high-brightness high divergence light emitting diode (LED), sized 1 mm × 1 mm, producing monochromatic emission (525 ± 5 nm) with viewing angle of 130°. The design is based on a rotationally symmetrical catadioptric system, developed on a geometrical optics basis, and modelled with ZEMAX® software. The device consists of two optical systems: (i) a collimating system which, in turn, is formed by an aspheric lenses system (low numerical apertures, NA < 0.26) and two-mirror system (0.26 < NA < 0.86), and (ii) an external mirror (NA > 0.86) designed and optimized for each purpose. By itself, the collimating system works with a residual divergence of θC = 1.46°. The external mirror can be adequately designed to produce some given conditions. For instance, a flat-top profile is obtained in the selected focusing plane, with a maximum transversal intensity variation of 2.5% over 18 mm. In addition, when the focusing mirror is allowed to move along the optical axis in a ±1 mm range, other interesting profiles can be reached for a given working distance, therefore increasing the versatility of the system. 相似文献