| 摘要 |
PURPOSE:To decrease electric current for illumination by setting a projecting means on the position where the projecting means can be guided in the light path of a movable mirror in a range finder where two images consist with each other, and detecting the distance by switching to one photoelectric element and receiving the light of the luminous source after connecting plural photoelectric elements when the brightness of the subject is low. CONSTITUTION:The light from a subject is incident to photoelectric elements 4a- 4c through half mirror 1 and the output are entered into distance detecting circuit 12 through switches S1-S3 to store the output ratio of 4a and 4c to the output of photoelectric element 4b. When the distance measurement starts, actor 5 is opened and movable mirror 5 starts to rotate. When the similar output ratio of photoelectric element 4 consists with the stored value, the distance set point is outputted from the OR circuit. When the brightness of the subject is low, switch 11 is changed over as shown in a dotted line by the output from detecting circuit 16 and connected to detecting circuit 13 and reflection mirror 8 jumps up. At the same time, oscillation circuit 17 operates and the light of luminous source 7 is reflected by mirrors 8 and 2 to illuminate the subject. Thus, electric current for illumination can be reduced. |
