Rangefinder apparatus

A rangefinder apparatus comprising:

• light-projecting means for projecting a luminous flux toward an object at a distance to be measured;
• light-detecting means for detecting reflected light of the luminous flux projected to the object at a light-detecting position on a position sensitive detector, corresponding to the distance to the object, and outputting a signal corresponding to said light-detecting position;
• arithmetic means for carrying out an arithmetic operation according to the signal output from said light-detecting means, and outputting a distance signal corresponding to the distance to the object;
• integrating means, having an integrating capacitor, for carrying out a first integration by discharging or charging said integrating capacitor according to the distance signal output from said arithmetic means by integrating the distance signal output from said arithmetic means, carrying out a second integration by charging or discharging said integrating capacitor with a constant current to a voltage, and comparing the voltage of said integrating capacitor to a reference voltage upon the second integration, and outputting a comparison result signal corresponding to the comparison;
• detecting means for measuring duration of the second integration according to the comparison result signal output from said integrating means, and detecting the distance to the object according to the duration measured;
• comparison result signal detecting means for detecting, when the comparison result signal is output by said integrating means, whether there is an output of the comparison result signal after a lapse of time from outputting of the comparison result signal;
• and
• measurement terminating means for terminating measurement of the duration of the second integration when said comparison result signal detecting means determines that there is an output of the comparison result signal.