Ultrasonic distance warning system esp. for motor vehicles - has aperture covering membrane carrying piezo-plate to eliminate group echos

摘要

A distance warning system, esp. for motor vehicles, has an ultrasonic transducer with a carrier for a pot-shaped vibration element holding chamber. The vibration element base forms a membrane carrying a piezo-plate on one side. The transducer transmits signals and receives and evaluates reflected signals received from obstructions. To reduce the detection region on one side of a plane of symmetry the membrane (22) is covered by an aperture (71) on the other side of the symmetry plane. USE/ADVANTAGE - Making parking easier without running into other vehicles. Aperture is used to eliminate ground echos.