| 摘要 |
PURPOSE:To eliminate the necessity for increase a luminous flux, by providing a photodetecting element of a linear traveling object or a stator, plural auxiliary photodetecting elements, a circuit which compares the outputs of the auxiliary photodetecting elements, and a position controller of a photodetector. CONSTITUTION:A projector 1 and a photodetector 2 are attached to rotors 4 and 5 and then liner drivers 6 and 7 to be driven in X and Y directions. The photodetector 2 has a photodetecting element 9 at the center part and auxiliary photodetecting elements (a)-(h) around the element 9. When the detector 2 moves toward X by (x) to the optical axis of the projector 1, the element (a) increases its photodetecting quantity more than the element (e). The position control is possible by performing a comparison of signals. So is with a case where the detector 2 turns round its optical axis. The rotary output shafts of rotors 4 and 5 have a 45 angle to the elements (b), (d), (f) and (h) respectively. An adder 12 is provided, and the rotor 5 is driven by an output 5 obtained through comparison and amplification given between addition outputs of elements (b) and (d) and those of elements (f) and (h). While the rotor 4 is driven by an output 4 obtained through comparison and amplification carried out between addition outputs of elements (b) and (h) and those of elements (d) and (f). Then rotors 4 and 5 and linear drivers 6 and 7 are driven so as to set each output at ''0''. |
