Patent ID: 6944397
Filing Date: 2005-09-13
Classification: G03B

Abstract:
1. A distance measuring device, comprising: light projecting means for projecting light onto an object at a distance to be measured; light detecting means for detecting light of the light projected to and reflected from the object and outputting a first signal corresponding to the distance to the object; integration means comprising an integration capacitor, for integrating the first signal by charging said integration capacitor according to the first signal; analog-to-digital (AD) conversion means for converting the voltage of said integration capacitor, after a predetermined number of distance measuring routines, including light projection by said light projecting means, light detection by said light detecting means and charging of said integration capacitor from a predetermined initial voltage level, into a digital signal as a second signal; and distance determination means for determining the distance to the object based on the second signal, wherein the predetermined number of the distance measuring routines to be performed is set so said integration capacitor, from the initial voltage level, substantially reaches a saturation voltage level of said integration capacitor when the distance measuring routines are performed, when the object is located at a short-range alarm position.