The new standards for the photometric characterization of light-emitting diode(LED)sources and luminaries require the measurement evaluation of photometric and colorimetric quantities.This present work studies the per...The new standards for the photometric characterization of light-emitting diode(LED)sources and luminaries require the measurement evaluation of photometric and colorimetric quantities.This present work studies the performance of some types of LED light sources in different spectra and different color temperature for photometric and colorimetric applications.The study depends on mixed spectra of these different types of LEDs to enhance the color rendering index(CRI)to be near as possible to standard sources.Characterization of LED sources requires the evaluation of some photometric and colorimetric quantities such as luminous flux(),chromaticity coordinates(x,y)and(u′,v′),correlated color temperature(CCT)and color rending indices(CRI).展开更多
In the present work, recalibration of the National Institute for Standards （NIS, Egypt） working standard lamps from Osram Inc. and their associated expanded uncertainty budget were done. A set-up composed of ...In the present work, recalibration of the National Institute for Standards （NIS, Egypt） working standard lamps from Osram Inc. and their associated expanded uncertainty budget were done. A set-up composed of an integrating sphere, a standard photometer and a group of five luminous flux standard lamps ranged from 25 to 200 W calibrated and traceable to the National Physical Laboratory （NPL, UK） is used to measure and recalibrate the total luminous flux for these five working standard lamps. After recalibration, NIS （Egypt） maintains the national scales for luminous flux in lumen.展开更多
文摘The new standards for the photometric characterization of light-emitting diode(LED)sources and luminaries require the measurement evaluation of photometric and colorimetric quantities.This present work studies the performance of some types of LED light sources in different spectra and different color temperature for photometric and colorimetric applications.The study depends on mixed spectra of these different types of LEDs to enhance the color rendering index(CRI)to be near as possible to standard sources.Characterization of LED sources requires the evaluation of some photometric and colorimetric quantities such as luminous flux(),chromaticity coordinates(x,y)and(u′,v′),correlated color temperature(CCT)and color rending indices(CRI).
文摘In the present work, recalibration of the National Institute for Standards （NIS, Egypt） working standard lamps from Osram Inc. and their associated expanded uncertainty budget were done. A set-up composed of an integrating sphere, a standard photometer and a group of five luminous flux standard lamps ranged from 25 to 200 W calibrated and traceable to the National Physical Laboratory （NPL, UK） is used to measure and recalibrate the total luminous flux for these five working standard lamps. After recalibration, NIS （Egypt） maintains the national scales for luminous flux in lumen.
