普通照明用LED模块光色性能测试方法的研究

随着LED技术的持续发展,其检测方法和评价标准成为了世界LED产业所面临的共同挑战。该文介绍了LED模块的光强分布、光通量、光强、相关色温、显色指数、色品坐标、色品容差、平均颜色不均匀性和最大颜色不均匀性等光色性能参数的测试方法,并结合自己在检测LED模块产品检测工作中的积累,总结了LED模块相具体条件下应选用的测试方法。     

基于误差反馈的LED阵列近场光强检测

发光二极管(LED)在机场、铁路等领域作为信号光源,通常采用多个LED组成阵列的方式。传统方法为拆卸后送入实验室中进行检测,此时无法获得光源在工作现场的状态且使得整个检测周期较长,针对上述问题提出一种基于照度误差的方法。在现场的近场区域内移动照度探头采集照度数据;再对各LED预设光强分布,计算此光强分布下在各测量点形成的照度与利用照度探头实际测量得到的照度的误差并根据此误差来更新设置的光强值,多次迭代至误差足够小;最后将此时计算得到的每个LED的近似光强分布进行叠加用于计算整个LED阵列的光强分布。通过该方法可以在现场快速准确检测灯具光强分布的同时,保障整个检测系统的设计能够便携。通过实验验证,所提方法在不同情况下能够完成光强检测,匹配度达到93%以上。     

基于非球面透镜组激光光束整形设计

本文针对激光显示领域激光光束光强均匀分布要求,本研究基于非球面透镜组激光光束进行整形设计。文中通过阐述激光光束光强均匀分布原理,着重论述了出射光束分布选择、线映射函数及球面参数确定3个非球面透镜组设计内容。在此基础上,选择匀化洛伦兹函数为输出光束的光强分布函数,展开实例设计分析,旨在基于该设计方法将入射光束准直的单模高斯激光光束整形为光强均匀分布的准直平顶激光光束。     

分布光度计法对LED光源及灯具光通量的测量

<正>一、前言在新兴半导体照明行业,由于LED产品的发光特性与传统的白炽光源不同以及整体式的灯具设计,传统光源或灯具通常采用的光通量的相对测量方法不再适用于LED产品,常用分布光度计对LED光源、灯具的光通量以及光强分布进行绝对测量。此外,由于LED的准单色性及空间光分布多样性等,对所使用的分布光度计提出了更高的要求。二、LED光通量的绝对测量1.分布光度计测量原理分布光度计是绝对法测量光源光通量的装置,其     

机动车灯具LED模块光通量测试方法规范与解析

汽车灯具的发展与灯具光源的发展密切相关,随着LED光源的深入应用,迫切需求对光源的检测方法进行研究,以LED光源模块不同位置的变换来探讨LED光源光通量,色谱分布的变化,研究LED光源模块光通量测试,推动我国在光源检测领域能有新的突破。文章选用机动车灯具检测中常用的检测方式,分别为照度积分法、光强积分法和积分球替代法。     

基于成像球光强测量系统的光学设计

提出一种新的快速测量空间光强分布的方法,完成基于该方法测量系统的光学系统设计,并对光学系统的关键器件进行设计.利用Matlab编程和Solidworks三维建模得到自由曲面反射镜面型,Zemax光学软件设计优化得到双高斯物镜.光线追踪仿真软件LightTools对测量系统进行模拟仿真,验证系统的可行性,并对该构架下测量系统最小角分辨率和动态范围的关键性能指标进行分析.结果表明,设计的基于成像球的测量系统可实现空间光强分布测量.     

基于LED的CCD光强响应特性测定

针对电荷耦合器件(charge-coupled device,CCD)的光强响应曲线的测量,提出采用大功率LED作为线性光源,设计基于成像方式的光强响应信号的测量装置。通过控制恒流激励电流大小来调节LED的辐射输出并测量CCD的响应数据。根据CCD响应信号拟合出对应的光强响应曲线,并建立光电响应模型分析CCD饱和与非饱和的响应特性。实验结果表明:CCD的光强响应受到LED发光角和辐射模式的影响,当采用LED作为CCD光强响应测量的线性可调光源时,不能忽视LED光强分布的近朗伯特性;同时,H694C-II相机输出灰度值大于61713时CCD ICX694AL的光强响应曲线出现较明显的饱和非线性,但在非饱和区域CCD具有优良的线性响应特性。     

一种计算大功率LED光源模块器件结温的方法

研究了大功率LED光源模块各器件之间热传导的相互影响,建立了一种基于热阻矩阵的LED光源模块器件结温计算公式,然后以一个由5只1W大功率器件组成的光源模块为例,演示如何通过测量器件的正向工作电压计算热阻矩阵,进而计算各器件的结温,并与现有方法计算值以及红外测温仪实际测量值进行了比较,结果表明：本方法比现有计算方法更为准确,可以用来预测LED光源的使用寿命和系统可靠性。     

采样间隔对分布光度计测量LED总光通量的影响

利用计算机仿真LED单管球面空间各点照度值的方法,模拟了分布光度计标定4种典型LED单管总光通量值的过程,利用计算结果分析了分布光度计测量所采用的不同采样间隔对标定结果的系统误差。这4种LED单管的光强分布曲线分别为准朗伯、长茄形、双翼形和窄光束,涉及轴对称或非轴对称光强分布。计算结果显示,对于常见的LED单管光源,利用分布光度计采用2°等间隔法,在球带份数m值大于12的情况下,采样间隔选择所带来的系统偏差可控制在0.3%以内。     

一种优化LED照明的三维SMS设计方法

二维SMS(多表面同时设计法)设计能实现旋转对称的照明目标,但不能实现像矩形光斑配光要求的非旋转对称的照明目标,为此介绍了一种优化LED照明的自由曲面透镜三维SMS设计方法。通过研究三维SMS方法的设计过程,详细分析了三维初始曲线的选取对于设计效果的影响:可以通过初始曲线的选取来使整个系统具有不同的性质,实现不同的设计要求。通过一个实例设计对三维SMS方法进行说明,并且通过改变种子肋的选取来得到所需要的矩形照明光斑。结果表明:三维SMS设计方法在实际LED照明设计中光线的控制能力强,透镜结构紧凑、效率高,可实现特殊要求的非旋转对称照明目标。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...     

Brainstorming for ISO Strategy 2016-2020

正Responding to ISO’s appeal for survey for the to-be-developed ISO Strategy Plan for 2016-2020,SAC hosted a special workshop over the needs and comments of various fi elds on June 8 in Beijing.The workshop was attended by ISO President-elect and Ansteel General Manager Zhang Xiaogang,SAC Vice-Administrator Yu Xinli,and 30 experts from     

CNAS Passes APLAC's PTP Review

正The review group of Asia Pacific Laboratory Accreditation Cooperation(APLAC)carried out a 4-day peer review of the proficiency testing provider(PTP)for China National Accreditation Service for Conformity Assessment(CNAS)from July 28 to 31,2014.CNAS passed the PTP review with excellent performance.Two senior peer reviewers of APLAC made a comprehensive,rigorous and detailed review of CNAS’s PTP accreditation activities,and made the on-spot inspection of the review groups in Shanghai and Shenzhen respectively.