Realization, multi-field coupled simulation and characterization of a thermo-mechanically robust LiDAR front end on a copper coated glass substrate

The thermo-mechanical robustness of Advanced Driving Assistance Systems is crucial to leverage the growing market of automated driving. Especially in case of optical sensors, such as camera and Light Detection and Ranging (LiDAR) sensors, the thermo-mechanical state of the sensor front end is closely coupled with its optical performance. Deformations in the optical path, consisting of the lens elements and imager, can cause major performance degradation like defocus. Additionally, the big Coefficient of Thermal Expansion (CTE) mismatch between the commonly used FR4 substrate and large silicon (time-of-flight) imagers, leads to extraordinary mechanical stress in the respective interconnects if operated under harsh automotive temperature conditions. Hence, within this work, an optical LiDAR front end on glass is realized in the form of reduced-complexity modules (RCMs) of the transmitter and receiver path. The transmitter RCM, consisting of a variety of small glass-mounted high power Vertical Cavity Surface Emitting Laser (VCSEL) diodes is tested and evaluated with respect to lifetime reliability, whereas the receiver RCM, consisting of a glass-mounted large-scale imager, is firstly investigated with regard to cooling under high temperature operation.