This paper discusses the results of driving tests using cars which were equipped with Full-LED headlamps - that means that all major functions like low beam, high beam, turn indicator, daytime running light etc. are using LEDs. The tests were realized with a statistically relevant number of test persons under realistic driving conditions on public streets in Germany. On the one hand a comparison with conventional light sources is discussed (technical benchmark with Halogen incandescent-, HID lamps) in order to give assistance in identifying possible problems in using/designing LED headlamps. On the other hand the results will distinguish unique advantages of LED headlamps. Headlamps which are using the same lamp technology and even were produced from the same manufacturer but only differ in the 'design' may have already a completely different light distribution/luminous flux. Therefore it is a challenge to compare completely different headlamp technologies (Halogen, HID, LED) in detail. Nevertheless the results of the test series T1 and T2 show some tendencies: The tested LED headlamp cars are ranked better than the testes halogen headlamps although they have a luminous efficacy of just 20 lm/W (the latest white LEDs which was measured in LED-Lab had about 75 - 80 lm/W under the same conditions). A well designed optics and a good quality of the chosen lens material is necessary more than ever in order to achieve a homogeneous luminance and color temperature distribution. This seems to be the most relevant factor to separate the 'just acceptable' from the 'excellent' systems. An outstanding advantage of LED headlamps (provided that a homogeneous color temperature distribution is given) seems to be the perceptibility of traffic signs and road markings. Additional tests are already in running at the Laboratory of Lighting Technology. Although the tested LED headlamps generate a luminous flux which is rather comparable to halogen headlamps the general perception of brightness is as good as HID headlamps. If this effect is caused by the higher color temperature or the spectral power distribution has still to be tested. Additional tests are already in progress.
First field tests of cars with completely built-in led headlamps under realistic driving conditions
Erste Feldversuche von Autos mit vollständig eingebauten LED Schweinwerfern unter realistischen Fahrbedingungen
2007
8 Seiten, 3 Bilder, 1 Tabelle
Aufsatz (Konferenz)
Englisch
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