AGC have developed a cover glass for automotive lidar sensors, and it has been chosen by a lidar maker through Belgium AGC Automotive Europe, a European automotive glass subsidiary.
AGC are aiming for mass production within this year, and recently presented the concept at the Automotive Engineering Exposition in Nagoya, Japan. The cover on an automotive lidar is required to protect the optics inside the lidar housing and to avoid obstruction or absorption of the laser beams which must pass through. AGC say their cover glasses outperform resin covers by being harder than current general-purpose products. A standard resin cover can be easily scratched by a gravel, where a cover glass will not be scratched at all. This aspect is one critical requirement of lidar manufacturers. Glass is also highly transparent to laser light, while plastic covers absorb a part of the laser beam.
In addition, the cover glass has excellent heat resistance, so it is possible to install a heater for melting snow and defrosting. Sensors used in ADAS and AD systems, including lidar, have to carry on working in any and all weather conditions. It is difficult to install heaters on a plastic cover, which can be deformed or otherwise degraded by the heat.
The remaining challenge for cover glass is the cost; plastic covers are cheaper. Glass is more difficult to work with, which is a factor in its higher cost. AGC are working to provide their cover glass at an competitively affordable price.
The protection of lidar optics is crucial, particularly against gravel and other normal road projectiles, as well as water; insects, and dust. Any obstruction or attenuation of the laser beam could cause a non-detection of some important object on the road ahead. Technical solutions are known for water management and dust removal, but against gravel the only solution is the hardness of the protecting material. Glass is therefore one of the solutions. The heater-compatibility of the glass cover is particularly attractive; newly-developed transparent heaters available for plastic covers suggest themselves, but an open question is their applicability to glass covers.