| 摘要 |
PURPOSE:To enable the omission of precise adjustment of a fitting angle, by eliminating a signal component appearing in the direction of Y or X due to a cross talk corresponding to an error of the fitting angle of a photodetector when a light beam oscillates in the direction of X or Y. CONSTITUTION:When a light beam 8 is made to oscillate in the direction X along a crossing line of a photodetector 1, a voltage corresponding to the amount of transfer of the beam 8 inputs from a terminal B and enters a differential amplifier circuit 15 and a variable resistance 10. On the occasion, a cross talk occurs in accordance with the amount of an error of a fitting angle of the detector 1, and a voltage corresponding to the amount of the cross talk is delivered from a differential amplifier circuit 6 and enters a differential amplifier circuit 14 and a variable resistance 11 from a terminal A. Then the circuit 14 amplifies the difference between the voltage coming in from the terminal A and a voltage sent out by a differential amplifier circuit 12 and sends out same to a terminal C. Therefore an output voltage of the circuit 14 can be minimized by adjusting the resistance 10 so as to equalize the voltage sent out by the circuit 12 to the voltage of the terminal A. When the light beam 8 is made to oscillate in the direction Y, likewise, an output voltage of the circuit 15 can be minimized by adjusting the resistance 11.
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