At higher luminance and adaptation level the LED lamps generate even more brightness impression. For the state-of-the-art high performance LED headlamps, the perceived brightness is 20% better. For the today existing lower performing LED lamps unfortunately the bonus for better brightness perception is only 10%. Putting all measurements together, the average of averages is 15%. This is good news. The bad news is that appr. 30% more photons were needed to detect the objects inside or outside the light pattern in about 50 m distance. LED threshold detection appears to be significantly weaker than Halogen. The reasons are unknown, a first explanation could be the differing spectral power distribution leading to different visual acuity and thus increased thresholds. This for sure needs further investigation before full acknowledgement. That means, LED lamps have great benefits in public awareness, they provide good light and are perceived even brighter. But it seems too simple to reduce photometrical properties just to lumens. Range and performance, i.e. lux and candela seem to be still important when considering and designing the optical concept for a good headlamp light distribution. Even with LED.
Reality check: How different is the perception of led-light vs. halogen-light on the road?
Wirklichkeitsprüfung: Wie unterschiedlich ist die Ausleuchtung des LED-Lichtes in Bezug auf Halogenscheinwerfer auf der Strasse
2011
12 Seiten, 12 Bilder, 1 Tabelle, 5 Quellen
Conference paper
English
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