Patent ID: 6456794
Filing Date: 2002-09-24
Classification: G01C,G01S,G02B

Abstract:
A distance-measuring apparatus comprising:light projecting means for projecting light toward an object at a distance to be measured; light detecting means for detecting light of the light projected toward that is reflected from the object, at a position on a position sensing photodetector device according to the distance to the object and outputting a signal according to the position on the position sensing photodetector device; arithmetic means for carrying out an arithmetic operation based on the output signal output from said light detecting means and outputting a distance signal according to the distance to the object; an integrating capacitor; integrating means carrying out a first integration in which the signal output from said arithmetic means is integrated by discharging/charging said integrating capacitor according to the signal output from said arithmetic means and, thereafter, carrying out a second integration by charging/discharging said integrating capacitor with a constant current, said integrating means comparing a voltage of said integrating capacitor with a reference voltage during the second integration and outputting a comparison result signal according to a result of the comparison; detecting means for detecting the distance to the object, based on the comparison result output from said integrating means; and charging means for precharging, by preliminarily applying a constant voltage to said integrating capacitor, prior to the first integration by said integrating means, wherein a plurality of distance measurement operations are carried out, each distance measurement operation measuring the distance to the object, by repeatedly projecting light from said light projecting means, detecting reflected light with said light detecting means, arithmetic operation of said arithmetic means, and integration by said integrating means, and said detecting means detects the distance to the object, based on results of the plurality of distance measurement operations, and the precharging by said charging means is carried out prior to a first distance measurement operation but not between the first distance measurement operation and second and subsequent distance measurement operations of the plurality of distance measurement operations.