| 摘要 |
PURPOSE:To detect a distance well even if an object is long or dark, by arranging prescribed optical member, secondary image-forming lens, and optical divider at the rear of a photographic lens and arranging a light source and a light receiving means at the rear of the optical divider. CONSTITUTION:If the object side is dark, the luminous flux from a light source 17 is projected to the object side through an optical divider 16, a secondary image-forming lens 15, a center part S1 of an optical member 13 where the center part S1 of a parallel plane is surrounded with a peripheral part S2 consisting of split prisms SP1 and SP2, a total-reflection mirror 2, and a photographic lens 1. The reflected luminous flux from the object is received by a divided photodetector 7 through a filter 9 and a light receiving lens 8 to measure the distance. If the object side is bright, the object image formed near a field lens 11 by the photographic lens 1 is formed the image again on faces of two photodetectors 18a and 18b through split prisms SP1 and SP2, the field lens 11, and the secondary image-forming lens 15 to measure the distance. Thus, the distance is detected well even if the object side is dark. |
