Abstract: In a clear viewing screen of the kind comprising a fixed screen element; a disk-like screen element supported for rotation at the outside of the window; a motor for driving the rotatable disk-like screen element supported at the inside of the fixed screen element; the motor to coupled the rotatable disk-like screen element, the motor mounted at the periphery of said rotatable disk-like screen element, and a magnetic coupling having first and second coupling halves is provided, one coupling half coupled to the motor, and the other coupling half coupled to the rotatable disk-like screen element, the coupling members disposed opposite each other on opposite sides of the fixed screen element so that coupling can take place without making a hole in the fixed screen element.