基于积分宽度法测量发光二极管结温方法的研究

本文提出了一种基于光谱积分宽度法来测量发光二极管(light emitting diode, LED)结温的新方法,并进行了理论分析和实验研究。本方法主要分为光谱数据采集、定标函数的测定和结温测量三个过程。首先,为了测量成本的降低和精度的提高而采用在正常工作电流下采集LED光谱数据,并通过采用不同温度下的光谱积分宽度与选定的某一基准状态下的值逐差可得到线性度达0.99以上的定标函数,并通过此定标函数可实时测定任意状态下的结温。其次,为了比较本方法测量结温的精确性,分别对单色和白光LED采用本方法和业界主流的正向电压法,通过自行设计的基于积分宽度法结温测量系统和美国Mentor Graphics公司的T3Ster型仪器的测量结果进行比较,两种方法测出的结温最大偏差为2.1℃,在可接受的误差范围内。实验结果表明积分宽度法测结温具有高效便捷且低成本的的特点,具有一定的应用前景。     

Ultra-Stable and Sensitive Ultraviolet Photodetectors Based on Monocrystalline Perovskite Thin Films

The detection of ultraviolet (UV) radiation with effective performance and robust stability is essential to practical applications. Metal halide single-crystal perovskites (ABX₃) are promising next-generation materials for UV detection. The device performance of all-inorganic CsPbCl₃ photodetectors (PDs) is still limited by inner imperfection of crystals grown in solution. Here wafer-scale single-crystal CsPbCl₃ thin films are successfully grown by vapor-phase epitaxy method, and the as-constructed PDs under UV light illumination exhibit an ultralow dark current of 7.18 pA, ultrahigh ON/OFF ratio of ≈5.22 × 10⁵, competitive responsivity of 32.8 A W⁻¹, external quantum efficiency of 10867% and specific detectivity of 4.22 × 10¹² Jones. More importantly, they feature superb long-term stability toward moisture and oxygen within twenty-one months, good temperature tolerances at low and high temperatures. The ability of the photodetector arrays for excellent UV light imaging is further demonstrated.     

Nanowire encapsulation with polymer for electrical isolation and enhanced optical properties

Light management and electrical isolation are essential for the majority of optoelectronic nanowire (NW) devices.Here,we present a cost-effective technique,based on vapor-phase deposition of parylene-C and subsequent annealing,that provides conformal encapsulation,anti-reflective coating,improved optical properties,and electrical insulation for GaAs nanowires.The process presented allows facile encapsulation and insulation that is suitable for any nanowire structure.In particular,the parylene-C encapsulation functions as an efficient antireflection coating for the nanowires,with reflectivity down to ＜1％ in the visible spectrum.Furthermore,the parylene-C coating increases photoluminescence intensity,suggesting improved light guiding to the NWs.Finally,based on this process,a NW LED was fabricated,which showed good diode performance and a clear electroluminescence signal.We believe the process can expand the fabrication possibilities and improve the performance of optoelectronic nanowire devices.     

Ultraviolet Photoluminescence of Carbon Nanospheres and its Surface Plasmon‐Induced Enhancement

Ultraviolet (UV) light can be used in versatile applications ranging from photoelectronic devices to biomedical imaging. In the development of new UV light sources, in this study, stable UV emission at ≈350 nm is unprecedentedly obtained from carbon nanospheres (CNSs). The origin of the UV fluorescence is comprehensively investigated via various characterization methods, including Raman and Fourier transform infrared analyses, with comparison to the visible emission of carbon nanodots. Based on the density functional calculations, the UV fluorescence is assigned to the carbon nanostructures bonded to bridging O atoms and dangling –OH groups. Moreover, a twofold enhancement in the UV emission is acquired for Au‐carbon core‐shell nanospheres (Au‐CNSs). This remarkable modification of the UV emission is primarily ascribed to charge transfer between the CNSs and the Au surface.     

一种拼接式大型矿用LED阵列显示屏的设计

针对地面应用的大型LED电子显示屏存在功耗大、不能应用到煤矿井下的问题,提出了一种拼接式矿用LED阵列显示屏的设计方案;给出了该显示屏的结构,详细介绍了该显示屏的硬件及软件设计。该显示屏可单独使用,也可与煤矿信息指引系统联合使用。调试与测试结果表明,该显示屏能够实时接收、显示上位机的图形、文字信息,达到了预期目标。     

半导体照明中结温的电学法测试与优化

基于电学法测试半导体照明的结温,实现了结温测试的电路,采用脉冲调制对LED的瞬态结温值进行测试.实脸发现,结温与正向电压的标定系数K值是影响结温测试精度的主要因素,分析了产生误差的主要原因,并对该系数进行修正.测试结果表明:结温的实测值与参考值有良好的一致性,存在误差的原因是采样的延时时间较长,可提高数据采样率和剔除不...     

P9816驱动的护栏管显示与控制系统设计

设计了护栏管显示与控制系统,给出了它们的硬件电路图。结合驱动芯片P9816的通信协议,编写了相应程序来控制护栏管的显示。系统采用控制器读取SD卡中的数据并进行处理,将处理后的数据送入护栏管,护栏管即可显示丰富多彩的内容。     

Phototherapy and the benefits of LEDs

Abstract— Light sources with wavelengths from near‐UV to near‐IR can cure skin diseases, relieve pain in the body, reduce wrinkles on the skin, treat acne on the face, grow hairs on head, and heal various kinds of other diseases. This is called phototherapy. Near‐UV, visible, and near‐IR LEDs now enable phototherapy viable for personal use because of the possibility of controlling the intensity of LED light with specific wavelengths. The medical applications of LEDs for phototherapy are reviewed.     

LED 晶圆贴片过程中压力的二阶段模糊决策与控制

针对LED 晶圆贴片过程, 设计一种利用阀门的开关和开度控制气缸内气压的压力控制系统, 提出一种多目标分阶段决策和控制的方法, 实现活塞运动和加压控制. 根据活塞的位移和压力, 采用逻辑决策方法, 选择需要控制的阀门. 根据规划压力与实测压力的差值及其差值变化率, 利用模糊自适应PID 控制方法控制阀门的开度. 采用半张量积的方法将逻辑决策和模糊控制中的推理转变成矩阵形式, 以简化运算量, 提高运算速度和控制精确度.

     

Development of active matrix LCD for use in high‐resolution adaptive headlights

Conventional adaptive driving beam headlamps are limited in achieving still higher quantities of switchable pixels by the number of LEDs and movable elements needed. In this paper, it is shown that by integrating an active matrix liquid crystal display module, it is possible to realize fully adaptive high‐resolution headlights without mechanical elements and a finite number of LED with 30 k switchable pixels.