Display devices with bridge emitters and sensors

Abstract

An electronic device may include a first and second projectors, first, second, and third waveguides, light sources, and optical sensors. The sources may emit calibration light into the third waveguide, which splits the calibration light between the first and second waveguides. Couplers on the third waveguide may couple the calibration light out of the third waveguide and partial reflectors on the first and second waveguides may reflect the calibration light back towards the optical couplers as reflected light. The couplers may provide the reflected light to the sensors, which generate electrical signals using the reflected light. Control circuitry may compare the electrical signals between different sensor locations to identify relative angles between the first waveguide, the second waveguide, the first projector, and/or the second projector. The control circuitry may use the identified relative angles to adjust projector images to compensate for optical misalignments over time.