Study On Color Apperance And Discomfort Glare Of LED Sources

Nowadays light emitting diodes(LEDs)are widely used because of their high efficiency,longer life and easy control.With the increasing use of LEDs,some problems have been revealed.One of the most important of these problems is glare.Because of the high luminance and small size of LEDs,they can cause more discomfort glare than traditional light sources,such as florescent lamps and tungsten lamps.So it is important to evaluate glare from LEDs.This paper contains two experiments.The first part of this paper describes an experiment to investigate discomfort glare caused by white LED lights having different spectral power distributions.It included two groups:a ’Metamerism’ group and a ’CCT’ group.In the former group,it was found that white lights at 7000 K constructed from different blue LEDs and the same red and green LEDs gave about the same glare perception.In the latter group,there was a significant difference in glare perception between white lights having different CCTs.Finally,glare models,including UGR and the newly derived QUGRspd,mUGRspd models,were tested using the data from the experiment.All of them gave quite accurate predictions of the data.In the second part of this paper,visual data were accumulated including glare and colour appearance from 81 kinds uniform light stimuli controlled by a multiple-channel LED lighting system.The results were used to verified the earlier proposed glare model based on colour appearance model.Also,the results were used to refine CAM 15u model.This part verified the QUGRspd,mUGRspd models.It showed that QUGRspd,mUGRspd and newly derived QUGR2spd can predict glare of colored LED well.And the brightness calculation of CAM15u has been revised by including HK effect.New glare model has been proposed.