Model predicting discomfort glare caused by LED road lights

Abstract

Abstract:To model discomfort glare from LED road lighting, the effect of four key variables on perceived glare was explored. These variables were: the average glare source luminance (L g ), the background luminance (L b ), the solid angle of the glare source from the perspective of the viewer (ω) and the angle between the glare source and the line of sight (θ). Based on these four variables 72 different light conditions were simulated in a scaled experimental set-up. Participants were requested to judge the perceived discomfort glare of these light conditions using the deBoer rating scale. All four variables and some of their interactions had indeed a significant effect on the deBoer rating. Based on these findings, we developed a model, and tested its general applicability in various verification experiments, including laboratory conditions as well as real road conditions. This verification proved the validity of the model with a correlation between measured and predicted values as high as 0.87 and a residual deviation of about 1 unit on the deBoer rating scale. These results filled the gap in estimating discomfort glare of LED road lighting and clarified similarities of and differences in discomfort glare between LED and traditional light sources.

Assessment of pedestrian discomfort glare from urban LED lighting

“…With RMSE higher than 3.7 on a scale with 9 levels, Sch74 and Lin14 models are not able to predict the mean glare ratings of our experiment, which suggests that these models should not be generalized too far away from their original data range. The illuminances employed to fit the Sch74 7 model were between 10 -3 and 10 -1 lx, much lower than the levels expected in pedestrian lighting; the background luminance of the case study is one order of magnitude lower than the range employed to develop the model Lin14 13 . Bul11 and Lin15 perform better with RMSEs lower than 1.4 and 0.9, respectively, and could be reasonably employed to predict pedestrian glare ratings.…”

“…The main photometric/geometric factors identified in the literature are the source luminance, the background or adaptation luminance 21 , the vertical illuminance at the eye of the observer 22 , the source eccentricity (angle between the observer's gaze direction and the source) and the solid angle of the source from the observer point of view. Based on these factors, various models have been proposed 7,9,[12][13][14]23 . In outdoor lighting, most of them predict a level of discomfort glare on a subjective scale, such as the de Boer scale 8 .…”

“…In heterogeneous real-world scenes, evaluating luminance values requires some choices. Previous work assessing these models 13,29 has been done by laboratory experiments and followed the method described in the original papers. Very few studies have implemented these models outdoors 30,31 .…”

Critical review on life cycle inventories and environmental assessments of LED-lamps

“…The study by Lin et al developed a new model to estimate discomfort glare particularly of LED road lighting expressed by the deBoer rating with the aim to guide practical illumination designs. The model addresses the illuminance from an LED light source falling onto the drivers' eyes, the contrast between light source and background, and the installed position of the road light (Lin et al, 2014). Villa et al investigated pedestrian discomfort glare from urban LED lighting.…”

Highly thermal-stable warm w-LED based on Ce:YAG PiG stacked with a red phosphor layer

“…At present, the phosphor-converted w-LED based on the "blue chips + yellow phosphor" technique has become a major approach to generate white light, and the yellow phosphor YAG:Ce 3+ dispersed in silicone (phosphor-in-silicone, PiS) is packed on the InGaN blue chips by conformal coating [4]. Unfortunately, the organic encapsulants featured with poor thermal conductivity and thermal/chemical stability would undergo aging and yellowing during the long-term service, which results in luminescent degradation and color aberration [5,6].…”