| 摘要 |
PURPOSE:To enable accurate infinite judgement, by judging whether a range finding object is positioned at the infinite point on the basis of two conditions of a renewed and set definite integration time and the integrated value at that time. CONSTITUTION:Light receiving means 5a, 5b receive reflected light from a range finding object obtained by projecting light to the range finding object from a light projecting means to output two kinds of signals relatively changing in dependence on the distance of the range finding object. An integration means 17 integrates the sum of two kinds of signals and either one of said signals and an operation means 9 stores the integrated values within the preceding definite integration time by the means 17 and renews and sets a lately definite integration time on the basis of the stored integrated values. Range finding operation is operated from the integrated values obtained by allowing the means 17 to perform integrating operation according to the renewed definite integration and the judgement of the infinite point is performed when the renewed and set definite time is a preset max. time and the integrated value of the summed signal is lower than an infinite judge level. |
