| 摘要 |
PURPOSE: To eliminate the requirements for arranging two light receiving means with a light projecting means as the symmetric center, for equalizing the effective aperture diameters of respective light receiving lenses and for equalizing the total lengths of respective sensors, to make the superimposing of external noises on the output of each sensor difficult, and to make it possible to facilitate the adjustment of the dispersion of the sensitivity of each sensor furthermore. CONSTITUTION: The first light receiving means has a first light receiving lens 52, which is separated from a light projecting 61 by the first base length and arranged, and a second sensor 71. The second light receiving means has a second light receiving lens 53, which is arranged being separated from the light projecting means by the second base length, and a second sensor 72. Adjusting means 121-124 and 131-134 electrically adjusting the outputs of the first sensor 71 and the second sensor 72, are provided. The outputs of the first sensor 71 and the second sensor 72 are adjusted by adjusting the gains of amplifier means 111-114, which amplify the outputs of the first sensor 71 and the second sensor 72. |
