| 摘要 |
<p>PURPOSE:To prevent the detection of uncertain deflection by stopping the evaluation of the deflection for a specified time when output saturation is detected, detecting the fact that the photocurrent flowing through a photodetector is less than a specified value, and prohibiting the evaluation of deflection when an SN ratio is decreased in order to prevent the erroneous detection of the deflection caused by the satuation of the output of a differential amplifier and in order to prevent the uncertain detection of the deflection when the SN ratio is decreased. CONSTITUTION:A light emitting element 12 projects the light toward an object to be detected by the driving with a driving circuit 14. Photodetectors 11 and 13 receive the reflected light of the projected light from the object to be detected and generate the first and second photocurrents. The inclination information of the object to be detected is outputted from operating circuits 16 and 17 based on the first and second photocurrents. In a minute-photocurrent judging part 15, the output based on the first or second photocurrent and a specified value are compared. When the output based on the first or second photocurrent is less than the specified value as a result of the comparison with the minute-photocurrent judging part 15, the detection of the inclination information is prohibited.</p> |
