High intensity discharge (HID) headlamps are the benchmark in today automotive front lighting and their performance is well-accepted. They provide more safety and reduce the number of nighttime accidents compared with tungsten halogen (TH) headlamps. However the discussion about headlamps during the last decades was often reduced to the aspects of glare. Today, glare is still important, but it has to be considered that it is just one out of many aspects for characterizing automotive headlamps. Concerning the aspects of glare, literature shows that the process of visibility loss (disability glare) has been well defined - for the first time already in the year 1927. But the subjective feeling of glare (discomfort glare) is distinctly more complex, different from disability glare and is less defined. The Laboratory of Lighting Technology at the Technische Universität Darmstadt has performed field tests in order to describe selected parameters more detailed, which could have an influence on the subjects feeling of discomfort glare. This paper discusses the impact of the headlamps optical concept (reflexion, projection), the drivers spectrum of adaptation (High Intensity Discharge, Tungsten Halogen) and the spectral power distribution of the glare source (HID, Tungsten Halogen) as possible factors. The choice of the own cars headlamps (TH or HID) has an influence on the subjects adaptation level, but has no real impact on discomfort glare ratings. Headlamps optics shows a distinct pattern. The tested TH reflector headlamps were detected to cause significantly higher discomfort glare than both TH and HID projection headlamps, which are leading to nearly identical feelings of discomfort.
Discomfort glare - Impact of headlamp optics, spectrum of adaptation and SPD
2009
7 Seiten, 3 Bilder, 3 Tabellen, 10 Quellen
Conference paper
English
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