2014 11th China International Forum on Solid State Lighting (SSLCHINA)最新文献_第4页

New developments in dimmable LED driver controllers 可调光LED驱动控制器的新发展

2014 11th China International Forum on Solid State Lighting (SSLCHINA) Pub Date : 2014-11-01 DOI: 10.1109/SSLCHINA.2014.7127229

Liang Yan, B. Chen

引用次数: 1

Research of spectrum effects on color visual performance at mesopic condition 介观条件下光谱效应对色彩视觉性能的影响研究

2014 11th China International Forum on Solid State Lighting (SSLCHINA) Pub Date : 2014-11-01 DOI: 10.1109/SSLCHINA.2014.7127216

Liting Jiang, Peng Lei, P. Jin

{"title":"Research of spectrum effects on color visual performance at mesopic condition","authors":"Liting Jiang, Peng Lei, P. Jin","doi":"10.1109/SSLCHINA.2014.7127216","DOIUrl":"https://doi.org/10.1109/SSLCHINA.2014.7127216","url":null,"abstract":"This paper studied spectrum effects on color visual performance under mesopic vision. Three types of light sources were studied, namely, high pressure sodium (HPS), phosphor converted white LED and RGB LED. Spectral power distribution (SPD) of HPS had a major peak around 590 nm, the white LED had peaks around 450 nm and 560 nm, the spectrum of RGB LED lamp peaked at 460 nm, 510 nm and 620 nm. The color appearance experiments [1] of those three light sources were carried out at illuminance of 5 lux, 10 lux and 20 lux, including forced judgments of the “most natural” and “most saturating” color appearance of familiar objects, color matching and mesopic color blindness detection. We found that SPD affected the performance of chromatic tasks. In the forced judgment of color appearance, 97% participants characterized white LED and RGB LED as the “most natural”, while 89% characterized RGB LED as the “most saturating [2]”. Color identification accuracy was slightly higher for white LED than that of RGB LED and significantly higher than that of HPS, and it correlated well with the selections of “most natural” and CRI. We also found that speed and accuracy in mesopic color blindness detection were noticeably higher for RGB LED than those of white LED and HPS, they also correlated with the selection of “most saturating” and S/P ratio.","PeriodicalId":361141,"journal":{"name":"2014 11th China International Forum on Solid State Lighting (SSLCHINA)","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130813089","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Degradation of high-power LEDs — Luminous flux and TM 21 life time 大功率led的退化-光通量和TM 21寿命

2014 11th China International Forum on Solid State Lighting (SSLCHINA) Pub Date : 2014-11-01 DOI: 10.1109/SSLCHINA.2014.7127241

H. Ganev, T. Khanh

引用次数: 2

The power of spectral composition 光谱组成的力量

2014 11th China International Forum on Solid State Lighting (SSLCHINA) Pub Date : 2014-11-01 DOI: 10.1109/SSLCHINA.2014.7127230

J. Rooymans

引用次数: 0

Application of thermal analysis for the development of reliable high power LED modules 应用热分析开发可靠的大功率LED模组

2014 11th China International Forum on Solid State Lighting (SSLCHINA) Pub Date : 2014-11-01 DOI: 10.1109/SSLCHINA.2014.7127246

G. Elger, A. Hanss, M. Schmid, T. Wipiejewski

{"title":"Application of thermal analysis for the development of reliable high power LED modules","authors":"G. Elger, A. Hanss, M. Schmid, T. Wipiejewski","doi":"10.1109/SSLCHINA.2014.7127246","DOIUrl":"https://doi.org/10.1109/SSLCHINA.2014.7127246","url":null,"abstract":"For the design of reliable light sources based on light emitting diodes (LED) efficient accurate testing is required. An innovative sensitive test method is developed to detect and distinguish failures in LED modules. The method, i.e. measurement of the relative thermal resistance, is based on transient thermal analysis and measures the structural integrity of the package by changes of the relative thermal resistance of the LED. Failure modes can be separated in the time domain. For detailed analysis and identification of the failure mode the transient signals are simulated by time-resolved finite element (FE) simulations. The sensitivity of the method is demonstrated in the paper. Test groups of ceramic LED packages were soldered on different Aluminum Insulated Metal Substrate (Al-IMS) and exposed to temperature shock tests. Transient thermal measurements were performed directly after assembly and after specific cycle numbers. After data processing the increase of the relative thermal resistance between the initial signal at `0' cycles and `n' cycles is obtained. Different failures can be observed, i.e. solder joint cracking and failures on die level. A large increase of relative thermal resistance of the LED package on the Al-IMS is observed for an Al-IMS with a thin dielectric layer. Due to the thin and hard dielectric layer the thermo-mechanical stress on the solder contact is higher and faster cracks growth takes place. The cracks are detected by their influence on the heat flow path within a certain time domain, i.e. 20-100ms. The new test method simplifies the thermal transient analysis by eliminating k-factor and thermal load measurement. It enables automatic data analysis of the transient thermal data required for processing large amount of data in production and reliability testing. Based on the method initial testing of the integrity of the LED packages and more accurate lifetime prediction is obtained.","PeriodicalId":361141,"journal":{"name":"2014 11th China International Forum on Solid State Lighting (SSLCHINA)","volume":"496 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116200959","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 6

The new generation package free LED: The performance and reliability of white chip 新一代无封装LED:白色芯片的性能和可靠性

2014 11th China International Forum on Solid State Lighting (SSLCHINA) Pub Date : 2014-11-01 DOI: 10.1109/SSLCHINA.2014.7127235

C. K. Wong, G. Q. Fan, S. Y. Y. Leung, C. Yuan, G. Zhang

引用次数: 3

Research on a novel constant power control strategy for single-stage PFC LED driver 单级PFC LED驱动恒功率控制策略研究

2014 11th China International Forum on Solid State Lighting (SSLCHINA) Pub Date : 2014-11-01 DOI: 10.1109/SSLCHINA.2014.7127208

Qingliang Zheng, Weiming Lin, Yuzhen Xu, Leiyu Wang, Nanbing Wu

引用次数: 1

Research and development of new generation High Voltage Flip Chip LED 新一代高压倒装LED的研究与开发

2014 11th China International Forum on Solid State Lighting (SSLCHINA) Pub Date : 2014-11-01 DOI: 10.1109/SSLCHINA.2014.7127220

S. Tan, Si Teng Zhang, T. Zhang

引用次数: 0

The development of LED street lamp pavement lighting effects testing system LED路灯路面照明效果测试系统的开发

2014 11th China International Forum on Solid State Lighting (SSLCHINA) Pub Date : 2014-11-01 DOI: 10.1109/SSLCHINA.2014.7127233

Benliang Li, Liwen Gu

引用次数: 2

Optoelectronic characteristics of a new alternating current light emitting diode 一种新型交流发光二极管的光电特性

2014 11th China International Forum on Solid State Lighting (SSLCHINA) Pub Date : 2014-11-01 DOI: 10.1109/SSLCHINA.2014.7127215

Ting Tian, Jinxia Guo, Yongbing Zhao, X. Yi, Zhiqiang Liu, Guohong Wang

{"title":"Optoelectronic characteristics of a new alternating current light emitting diode","authors":"Ting Tian, Jinxia Guo, Yongbing Zhao, X. Yi, Zhiqiang Liu, Guohong Wang","doi":"10.1109/SSLCHINA.2014.7127215","DOIUrl":"https://doi.org/10.1109/SSLCHINA.2014.7127215","url":null,"abstract":"Recently, the alternating current light emitting diode (AC LED) has been investigated and was regarded as a potential device for solid state lighting. In this study, we report a new design of the alternating current light emitting diode integrating Wheatstone Bridge (WB) circuit which has two output branches. The new type AC LED effectively increases the chip area utilization ratio to be about 70% in each bias direction, which can improve the device efficiency. Compared with the AC LED driven by DC source, the light output power of the AC LED driven by AC source was reduced by 17.8% under the input power of 1 W. Based on time resolved current and driving voltage properties, it is found that the AC LED was turned on only half the time in one cycle, which leads to the increase of driving current for the same input power. According to calculation, 79% illuminating duration of the AC LED driven by AC was higher than the driving current of AC LED operating in DC. Therefore, the serious efficiency drooping phenomenon caused by the higher driving current and injection current density results in the decline in the light output efficiency of the AC LED.","PeriodicalId":361141,"journal":{"name":"2014 11th China International Forum on Solid State Lighting (SSLCHINA)","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124773651","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0