Comparison of Luminous Efficiency of InGaN-based High-voltage LED with Traditional High Power LED

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%。The reasons of the luminous efficiency of In Ga N-based high-voltage light-emitting diode(HV-LED)better than that of traditional high power(THP) LED are researched and analyzed from three different aspects.Theexperimental sample with same chip size, material and package structure is adopted to ensure the reliability of ex-periment conclusions.Experiments show that the luminous efficiency of HV-LED is better than that of THP LED foruniformer current distribution and the light from the microchip gap.The results show that the luminous efficiency ofHV-LED is approximately 4.5% higher than that of THP-LED under 1 W input power.国家863项目(2013AA03A107); 福建省产学研重大科技项目(2013H6024); 福建省重点科技项目(2012H0039)资

Design of a Temperature-Controlled Test System for Luminous Intensity Spatial Distribution Characteristics of High Power LED

发光二极管(lEd)的光强空间分布特性决定了它能否满足特定场合的应用。大功率lEd由于发热量大,其绝对光强空间分布(lISd)的测试也必须在特定热沉温度下进行才能得到准确可靠的结果。设计了一个可对大功率lEd进行热沉温度控制且快速实现lISd自动测试的系统。该自动测试系统基于lEdgOn-100测角光度计及其高精度的二维旋转台,配合测试适配器、温度控制器、光度探头、kEITHlEy 2400源表和测试软件组成。测试软件基于dElPHI程序语言开发。在控温条件下,该lISd自动测试系统稳定可靠,测试时间大大缩短,测试结果实时直观。利用该自动测试系统对具有朗伯型和蝙蝠翼型两大lISd类型的lEd进行测试,获得它们的二维lISd和三维lISd。实验结果表明:随着热沉温度的增加,光强绝对值下降,而相对lISd却不变。Characteristics of the luminous intensity spatial distribution(LISD) of light emitting diodes(LEDs) are capable of determining whether these devices can be applied on specific occasions.The absolute LISD of high power LED can be accurately measured only when LED is fixed at a specific heat- sink temperature because of the LED′s large heat-generating capacity.In this study, an automatic test system based on LEDGON-100 goniophotometer and the meter′s high-precision two-dimensional(2D) revolving platform, is designed.In addition, it comprises of a test adapter, a temperature controller, a photometer head, a Keithley 2400 source meter, and an in-house-developed software package.This assembly can both control heat-sink temperatures and measure the LISD characteristics rapidly for high- power LEDs.The software is developed using Delphi programming language.The test system is stable and reliable.The test time is greatly reduced and measurements are instantly displayed.Two general types of LEDs, Lambertian type and batwing type, are measured by the system to obtain their 2D and three-dimensional(3D) LISDs.Experimental results show that the absolute luminous intensity decreases as the heat-sink temperature increases.However, the relative LISDs are the same under different heat-sink temperatures.国家自然科学基金(11104230); 福建省重大科技项目(2011H6025;2012H0039

Real-time spectrum testing system for LED based on Delphi

lEd实时光谱能反映lEd动态光学特性的变化情况,光谱的测量要求光谱仪在合适的积分时间条件下完成从收集光子到处理数据的过程。利用Hr4000光谱仪、gS610源表和gPIb控制卡,开发了1套基于dElPHI7.0的实时光谱数据采集系统,该系统能快速、精确地采集lEd光谱并计算色坐标、色温、峰值波长等光学特性参数。同时还设计了1种基于二分法的自动设置光谱仪积分时间的计算方法,实现了对lEd稳态、瞬态光谱实时测试的数据采集和处理,并通过实验分析,研究了瞬态测量方法的可行性以及条件。Real-time spectrum can reflect dynamic optical properties of LEDs.To meet the spectrum measurement requirement,the spectrometer shall own the capability of collecting photons and processing the data under the appropriate integration time.By using HR4000 spectrometer,GS610 source and GPIB control card,a Delphi7-based spectral data acquisition system is developed,which can instantly and accurately collect LED spectrum and calculate other optical parameter,such as color coordinate,color temperature,peak wavelength.Besides,we designed an algorithm to set the integral time of spectrometer automatically based on the dichotomy method.The system can realize both the steady and transient data acquisition and processing of LED spectrum.By experimental analysis,the feasibility of transient measuring method and condition has also been studied.国家自然科学基金(11104230); 福建省重点项目(2012H0039); 福建省产学重大项目(2011H6025;2013H6024