| 摘要 |
<p>PURPOSE:To make it possible to prevent and adjust erroneous operation by continuously moving the position of a light reducing plate with respect to a light projecting window and a light receiving window, and continuously adjusting the light reducing amount. CONSTITUTION:In order to slide a light reducing plate 5 up and down with respect to a main body 2 of a detector, both bending pieces 51 of the light reducing plate 5 are pushed from the sides. Then, dowel projections 52 are floated out of grooves 22, and sliding can be performed. When the pushing is stopped, the dowel projections 52 are coupled into the grooves 22 again, and the light reducing plate 5 is fixed. Therefore, the area covering a light projecting window 12 and a light receiving window 13 can be continuously varied. Thus, the light reducing amount can be continuously adjusted.</p> |
