Patent ID: 6148151
Filing Date: 2000-11-14
Classification: G02B,G03B

Abstract:
A control system for an objective of a camera, comprising:at least one lens ring disposed on the objective;at least one drive unit or automatically adjusting a position of the lens ring to a predetermined desired state; andat least one position determining means coupled to the lens ring for determining an actual position of the lens ring relative to the objective, said position determining means converting the actual position into a measuring output signal,wherein the position determining means includes a waveguide extending about the circumference of the objective in the region of the lens ring, a magnet connected to the lens ring at a predetermined location and at least partially movable inside the waveguide, an electromagnetic transmitter element, and an acoustic receiver element arranged in the waveguide, wherein the electromagnetic transmitter element transmits a signal that is received by the acoustic receiver element and wherein a time difference measured between transmission of the signal by the electromagnetic transmitter element and reception of the signal by the acoustic receiver element represents the measuring output signal.