This study evaluated the effect of blue content of headlamps on discomfort glare, in order to provide guidance regarding spectral compositions that would minimize driver complaints. Three LED headlamps were tested (with correlated color temperatures of 4000, 4800, and 6600 K) as well as a tungsten-halogen headlamp and a HID headlamp. Subjects, seated in a stationary vehicle, rated discomfort from brief presentations of stimuli that produced illuminances of 0.25, 0.5, and 1 lux. As predicted in a previous analytical study, the authors found that - when they appear bluer than current tungsten-halogen or HID headlarnps - LED headlamps tend to produce more discomfort glare. The effect is probably due to the color appearance of the LED lamps used in this study rather than to any inherent characteristic of LED sources, and it could probably be altered or reversed with different sources. The main finding was that, for both younger and older observers, an increase in the correlated color temperature (which is strongly correlated with blue content over the range of interest) was associated with an increase in discomfort glare. The present study was designed to replicate the main elements of a JARI study with U.S. observers, and to further explore the potential mechanisms underlying discomfort glare. For ease of comparison, the present study used the same LED lamps as the JARI study. For the data reported here, ratings of discomfort glare were linearly related to the amount of blue content in the light output as weighted by the spectral sensitivity of the short-wavelength (blue) cone photoreceptors. Therefore, if this relationship is replicated and extended in future studies, it may provide an index of blue content that could be used heuristically to select colors of headlamps to minimize driver complaints about glare.
Blue content of LED headlamps and discomfort glare
Blauanteil von LED-Scheinwerfern und störende Blendung
2005
10 Seiten, 3 Bilder, 2 Tabellen, 10 Quellen
Conference paper
English
Blue Content of LED Headlamps and Discomfort Glare
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