Determining the effects of sharp cut-off lines vs.smooth cut-off lines on glare rating

  In recent years new headlamp developments have made improvements for driver's safety.Starting from halogen headlamps, the next major step in increasing night time drives, is made by the introduction of HID headlamps.Due to its new design,it is possible to achieve more light for the driver, and by sharpening the cutoff line, it is possible to get more light closer to the horizon without changing the headlamp aiming.In combination with the increased luminous flux this enables detection distances much higher than those achieved with halogen headlamps with smooth cutoff With the current development of new high resolution LED systems, it is possible to create nearly homogeneous light distributions, thus theoretically creating a perfectly sharp cutoff.While this might result in higher detection distances compared to traditional systems like halogen, HID or even simple LED, road unevenness might also cause much higher glare.This is due to the fact that small changes in vehicle inclination could cause the light beam and by this the cutoff line to be lifted up to and over the eyes of a potentially oncoming driver.At the Technische UniversitiitDarmstadt a laboratory study is performed to determine the effect of different gradients in the cutoff of headlamps.For this purpose, a group of test subjects is shown different light pulses that are being varied in duration, peak intensity and shape.Peak intensity is varied from 0.04 lx to 11.28 lx to simulate different headlamp intensities.Durations are chosen from 0,3 to 40 s to simulate different types of road unevenness.All light pulses are selected to form sets with equal exposure rates and to be able to compare between the selected pulse shapes.Two shapes are selected: a triangle and a square, to simulate as explained above, the two extreme possibilities of cutoff lines, smooth and hard.

作者单位: Laboratory of Lighting Technology,Technische Universit(a)t Darmstadt,Germany
母体文献: 第五届中国国际汽车照明论坛论文集
会议名称: 第五届中国国际汽车照明论坛
会议时间: 2017年1月1日
会议地点: 上海
主办单位: 中国照明学会,中国汽车工业协会
语 种: eng
在线出版日期: 2017年8月31日