浅析全彩LED显示屏功耗能效等级的划分

本文主要围绕全彩LED显示屏的功耗问题进行分析，着重讨论了显示屏节能标准制定过程中需要重视的几个问题，如标准视频源的选定、立体角的引用、亮度的科学测量、效率系数的计算，从而为制定LED显示屏功耗能效等级相关标准提供建议。     

城市隧道照明设计探讨

根据近些年的城市隧道工程设计经验,介绍了隧道照明的设计依据、标准及基本要求,分析了城市隧道照明设计的照明标准值、灯具布置、应急照明、照明控制、配线、节能措施等方面内容,并对隧道照明工程设计实例进行了探讨。     

Simplified electrical modelling of power LEDs for DC–DC converter analysis and simulation

This paper presents a model of power light emitting diodes (LEDs) based on electrical variables and considering the concept of LED ‘equivalent resistance’, which has previously been used in discharge lamp modelling and is suitable to achieve fast simulations of LED converter systems. The model can be obtained with only some simple electrical measurements, thus making its implementation quite straightforward. The proposed model is oriented to the electronic engineering area, and it has special application for the simulation of the electrical behaviour of LEDs and dc–dc converter systems by using software like Simulink. In addition, the proposed model can also be employed for the theoretical analysis and design of LED drivers. Experimental and simulation results are obtained proving the feasibility of the proposed model. Copyright © 2017 John Wiley & Sons, Ltd.     

What encourages local authorities to engage with energy performance contracting for retrofitting? Evidence from German municipalities

Municipalities aiming at mitigating climate change by implementing new energy efficiency technologies face budgetary and capacity constraints. Outsourcing through energy service contracting could provide a solution. This paper reports results from a survey of 1298 municipalities concerning barriers to retrofitting public street lighting and the possible role of energy service contracting to overcome these barriers. Using a logistic regression analysis, the authors investigate determinants of opting for energy service contracts in the specific context of LED retrofits. Results point to an advantage of outsourcing in a financially and capacity-constrained environment, which corresponds with the main reasons for engaging in contracting: minimising investments and financial risks. However, municipalities often do not fully grasp the risks associated with retrofitting especially using a novel technology such as LED. In relation to that they underestimate the risk reduction potential of energy performance contracts (EPC). Previous experience with outsourcing increases the probability to engage in servitization although certain existing partnerships, particularly with utilities, prevent municipalities from considering energy performance contracts. Interestingly, engaging an energy consultant has a negative propensity to use energy service contracts, while pre-negotiated standardised contracts for energy performance contracts have a positive influence.     

High-performance and current crowding-free InGaN-GaNbased LEDs integrated by an electrically-reverse-connected Schottky diode and a Mg-delta doped p-GaN

This work demonstrates high-performance and current crowding-free InGaN/GaN light-emitting diodes (LEDs) using an electrically-reverse-connected Schottky diode (SD) and an Mg-delta (δ) doped layer.Poss...     

Reliability and optical properties of LED lens plates under high temperature stress

In this investigation the thermal degradation mechanisms of Bisphenol A Polycarbonate (BPA-PC) plates at the temperature range 100–140 °C are studied. The BPA-PC plates are currently used both in light conversion carriers in LED modules and optical lenses in LED-based products. In this study BPA-PC plates are aged at elevated temperature of 100–140 °C for a period up to 3000 h. Optical and chemical properties of the thermally-aged plates were studied using UV–Vis spectrophotometer, FTIR–ATR spectrometer, and integrated sphere. The results show that increasing the thermal ageing time leads to yellowing, loss of optical properties, and decrease of the light transmission and of the relative radiant power value of BPA-PC plates. The results also depict that there is not much discoloration within the first 1500 h of thermal ageing. The rate of yellowing significantly increases at the end of this induction period. Formation of oxidation products is identified as the main mechanism of yellowing. An exponential-based reliability model is also presented to calculate the rate of degradation reaction and to predict the life-time of BPA-PC plates.     

户外LED显示屏图像质量主观评价初探

当前户外LED显示屏的图像质量主要靠业内人士进行简单的主观评价，不确定因素多，尚未形成规范的评价标准。本文参考通用的图像质量主观评价方法，针对LED显示屏显示特性，探讨了主观评价中的各个环境因素的控制方法，并定义了一系列主观评价测试图像的类型，能对显示屏的均匀性、对比度、色彩还原性等显示性能进行更规范更全面的评价。     

LED节能灯的安规要求

根据CTL发布的DSH 0743决议,归纳了LED节能灯测试标准中的要求,主要包含对灯头、防触电、灯头温升、绝缘材料、异常状态、结构的考核,以及灯的光生物学安全考核。     

InGaN基高压LED和传统大功率LED的发光效率比较

主要从三个不同角度探究并分析了基于In Ga N材料的高压LED的发光效率优于传统大功率LED的原因。为了保证实验结论的可靠性,文中所采用的实验样品具有相同的芯片尺寸和材料以及相同的封装结构。经过大量的实验证明,更均匀的电流分布和小芯片间隙的出光,使得高压LED的发光效率优于传统大功率LED。结果显示,在相同的1 W输入功率下,高压LED的发光效率比传统大功率LED高大约4.5%。     

基于蓝宝石纳米图形衬底上氮化镓生长的研究

利用两步生长法在蓝宝石纳米图形衬底（NPSS）上生长得到高质量的氮化镓薄膜。通过XRD和SEM对薄膜质量的表征和研究发现,为得到高质量的氮化镓（GaN）薄膜,在NPSS上生长时得到的最优缓冲层厚度为15nm,而在微米级尺寸的图形衬底（MPSS）上得到的最优缓冲层厚度远大于15nm。同时,在NPSS上生长氮化镓薄膜的过程中观察到一个有趣的现象,即GaN在NPSS上生长的初始阶段,氮化镓晶粒主要在图形之间的平面区域生长,极少量的GaN在衬底图形的侧面上聚集生长。这一有趣的现象明显不同于GaN在MPSS上的生长过程。接着,又在NPSS上生长了GaN基LED结构,并对其光电性能进行了研究。