The limitation of glare for automotive headlamps is today solely based on maximum values of illuminance on the measuring screen of the ECE (Economic Commission for Europe). Further parameters and criteria like the spectrum of the glare source and the size of the light emitting area of the headlamps are not considered as critical to minimize glare. The influence of glare source luminance on disability glare and discomfort glare from oncoming cars was investigated. The glare illuminance was set to three levels commonly found in traffic situations, and at each illuminance level, the luminance of the glare source was varied by suitably adjusting the size of the glare source. The results show a significant influence of luminance on both, discomfort glare and disability glare. Threshold contrast as a criterion for disability glare increased slightly with increasing luminance, but this occurred only at the intermediate and high glare illuminance levels, which were not considered relevant in automotive lighting. Subjective ratings show a strong and relevant increase in discomfort for small glare sources with very high luminance levels. The experimental results further confirm the strong effect of glare illuminance on disability as well as discomfort glare shown in former studies. There was only a small effect of luminance on the rise of the contrast sensitivity during glare, and this is not considered relevant for traffic situations. But small and high luminance sources did give rise to substantially more discomfort at constant glare illuminance levels. This effect is found to be relevant in traffic. These results ought to be considered when designing new headlamps especially headlamps using new light sources like LED's. To limit the disturbance by glare, one should avoid minimizing headlamp size in favour of design.
Luminance as a criterion for the evaluation of discomfort and disability glare of headlamps
Die Beleuchtungsstärke als ein Kriterium für die Bewertung des unangenehmen und des behindernden Blendens von Scheinwerfern
2007
7 Seiten, 7 Bilder, 1 Tabelle, 7 Quellen
Conference paper
English
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