| 摘要 |
PURPOSE:To achieve a higher accuracy by a method wherein N+1 pieces of light emitting elements are driven to emit light by false random signals varied in the phase and lights projected therefrom are received with one light receiving element to enable a colse arrangement of the light emitting elements. CONSTITUTION:For example, when an object 4 exists at the position as indicated by the solid line, a light receiving element 7 receives light projected from light emitting elements 5(5a-5d). Correlative outputs of the outputs G-J of correlation circuits 8a-8d are taken into a latch circuit 92 by a sample signal K. Then, a decoding is done with a decoder 93 and output termianls E1-E4 all produce ''0''. Then, when the object 4 comes to the position (a) as indicated by the broken line, the light emitting element 7 receives no light projected from the light emitting element 5a, which turns the signal G to ''0'' and the signals H-J to ''1''. Therefore, the decoder 93 gives the H level to an output terminal E1. |
