Dynamic, laterally multiplexed, wide angle holographic projection

Vehicles driving autonomously require communicating with their surroundings, e.g. to inform nearby pedestrians and cyclists about being recognized by the car. When projecting symbols onto the road around the vehicle, the illuminance must compete with that of a sun-lit road. This cannot be achieved by small, LED-based projection systems. Furthermore, a large angular projection range is desired to address the whole circumference of the car. Both requirements have been met by a system approach that combines four high power laser diodes, each of which generating one part of the finally projected scene. The collimated beams of these four sources are directed onto one SLM (HOLOEYE) with offsets in both the lateral position as well as the angle of incidence. While the first enables to display one dedicated phase pattern for each beam, the second reduces necessary beam steering efforts to reach maximum horizontal projection angles up to ±45°. In result, 100 x 30 cm2 sized stitched patterns can be projected onto the road close to the car. Acknowledgment: The project had been funded by the Bundesministerium für Bildung und Forschung (BMBF FKZ 03ZZ0449G).