LED rear lamps and adaptive rear lamps- technology, standards and lighting aspects

Authors: Dr.-Ing. Dmitrij Polin, Prof. Dr.-Ing. habil. Tran Quoc Khanh

In recent years, LED-efficiency has increased strongly. Hence, LEDs can be used both in rear position lights and in stop lights which need ten times higher luminous intensity. Taillights are nowadays not only just functional elements; they become an important style element. LEDs allow designs with small emitting surfaces which lead to a high luminance. Depending on taillight type, the hot-spot luminance can be in the range of Mcd/m². Many people in Germany complained about getting glared by LED stop lights. At the Laboratory of Lighting Technology, TU Darmstadt, we investigated which luminance of rear lights is more appropriate at nighttime.

Our study was performed on enclosed test track with 20 volunteers. There were three types of rear lights with different luminance distribution. The test person had to rate the luminance at different intensity levels using a scale from 1 to 9. In order to simulate different driving situation, the rating was performed at four distances of 5, 20, 50 and 100 m.

This paper outlines the findings of the conducted study. Furthermore, a proposal of an improvement suggestion to the ECE-Regulation R48 will be present. Finally, technical implementation and possible drawbacks will be discussed.