| 摘要 |
PURPOSE:To raise a distance measuring accuracy by placing adjacent photodetectors so that the polarity becomes opposite to each other, and obtaining distance information basing on a difference of their signal photodetecting quantities. CONSTITUTION:Plural photodetector trains 4a, 4b,...4e are placed so that the polarities of adjacent elements become opposite to each other. From the difference of photocurrents flowing in the element trains 4a, 4b, if the photocurrent flowing to the element train 4a is more, an output signal of a synchronous detecting circuit 10 becomes plus against a reference voltage V2. On the contrary, if the current flowing to the element train 4b is more, said signal becomes minus. In the same way, in case of the element trains 4b, 4c, the element trains 4c, 4d and the element trains 4d, 4e, what they become against the reference voltage V2, V3 and V4 is detected by the synchronous detecting circuit 10. If an image S' exists, for instance, on the element train 4d and 4e, L and H are outputted from a comparator 48 and an invertor 60, respectively. Subsequently, a signal K4 is latched to H by a flip-flop 33. |
