| 摘要 |
PURPOSE:To obtain the detection signal of a light shielding object by light receiving amplifiers reduced in the number thereof as compared with the number of detecting means, by a method wherein currents flowing to a plurality of light emitting elements are timewise shifted while the outputs of the light emitting elements are connected in parallel to be inputted to an amplifier means and inputted to temporary memory means provided in corresponding relation to the number of the light receiving means. CONSTITUTION:The pulse signals A, B, C of a signal generating circuit 10 drive photodiodes 21-23 through drive circuits 111-113 and, because said signals are successively outputted in time sharing, the photodiodes does not simultaneously emit lights. The light receiving signals of phototransistors 61-63 are exhibited while leaving stepwise shift and output signals appear while are timewise shifted corresponding to the light shielding or light non-shielding states of sensors PS1- PS3. When the outputs of light receiving amplifiers 7 are aligned to the light emitting timings of the sensors PS1, PS2, PS3 and stored in corresponding latch circuits 91, 92, 93, signals corresponding to the light shielding or light non-shielding states of the sensors PS1, PS2, PS3 can be taken out. |
