| 摘要 |
<p>PURPOSE:To simplify a wiring without increasing a simultaneous detection circuit, by disposing a plurality of projector-receivers to be opposite to each other so that each of them does not receive its own projection light, but receives the projection light from others. CONSTITUTION:A projector-receiver 1 is composed of a projector 11 and a receiver 13, and a light-emitting element 12 and a light-sensing element 14 are juxtaposed in the front thereof, while a light-intercepting plate 15 is provided so that a light of the light-emitting element 12 of its own does not enter the light-sensing element 14. When it is assumed that the light is projected from the light-emitting element 12 and simultaneously a light from another projector- receiver enters the light-sensing element 14 on the occasion when a projection signal is inputted, a reception signal is generated from the receiver 13 and and synchronism of the projection signal with the reception signal appears. Therefore, a logic product (AND) circuit 16 detecting said synchronism and outputting a detection signal is connected to one projector-receiver 1, respectively. By providing a number of projector-receivers 1 to each of which this AND circuit 16 is connected and which are made to face each other, the coincidence between any two signals out of a number of signals can be detected.</p> |
