Rearview mirror for a motor vehicle

The rear view mirror (01) for a motor vehicle has a partially transparent mirror (03) for observing adjacent following traffic. On the rear face of the mirror is a signal display with a light emitting diode (05,07). The light is emitted over a limited angular range in a required direction. Between the light source and the mirror is an optical focussing lens (11,12) which is adjustable to vary the viewing angle.