Patent ID: 6650425
Filing Date: 2003-11-18
Classification: G01D

Abstract:
A position measuring laser apparatus comprising:a first laser transmitter-receiver and a second laser transmitter-receiver, each including: a laser beam emitter for emitting a laser beam; a laser beam receiver for receiving a laser beam resulting from the emitted laser beam reflected from a reference reflecting mirror, a position measuring circuit including: a first output portion for outputting the drive signal having a required frequency to the laser beam emitter; a timing generator for generating a timing signal to be set based on a frequency of the drive signal; a coincidence detector for comparing the beam receiving signal with the drive signal based on the timing signal, so as to detect the coincidence therebetween; a second output portion for outputting an effective beam receiving signal when the coincidence is detected in sequentially predetermined times by the coincidence detector, wherein an optical axis is oriented at a required angle toward a moving body, and the position of the moving body with respect to the reference reflecting mirror is measured based on a beam receiving signal of each of the laser beams obtained by said first and second laser transmitter-receiver; further wherein the position measuring circuit measures the position of the moving body based on said effective beam receiving signal.