Near-Infrared Reflective Dark-Tone Bilayer System for LiDAR-Based Autonomous Vehicles

Abstract

Light Detection and Ranging (LiDAR) is a representative sensor for autonomous vehicles (AVs) by recognizing surrounding objects through detecting the reflected near-infrared (NIR) light However, this sensor has a weakness in recognizing the conventional carbon black-based dark-tone cars due to their low NIR reflectance. This cognitive impairment is a potential factor in a car accident in the AV system. Therefore, it is necessary to develop a dark-tone paint that can be applied to LiDAR by reflecting NIR In this work, we developed a NIR reflective dark-tone bilayer system. As the bottom layer (surfacer layer), we used a conventional NIR-reflective surfacer. For the dark-tone top layer (basecoat layer), organic pigment-based paints were prepared. Various combinations of organic pigments such as perylene, copper(II) phthalocyanine, perylene diimide derivatives were studied to give a dark tone. After optimization, the developed bilayers exhibited dark tone with low L* values (less than 25) and high reflectance in the NIR region, over 60%, especially at 905 nm. Therefore, we expect the developed bilayer system to be applied as a dark-tone paint detectable by LiDAR.