| 摘要 |
PURPOSE:To set a current removing circuit connected to a far point side electrode more easily becoming a saturated state than a current removing circuit connected to a near point side electrode by setting the relation between the resistor and resistance value to satisfy a specific condition to the current removing circuits of a signal processing circuit connected to both end electrodes of a photoelectric, conversion element. CONSTITUTION:Electrodes 6a, 6b at both ends of a photoelectric conversion element (PSD) 6 are set to satisfy the condition R1>R2, where R1 is the resistance value of a resistor 10 connected in series to the transistor 9 of the current removing circuit of a signal processing circuit A connected to the far point side electrode 6a on a light projecting means 1 side, and R2 is the resistance value of a resistor of the circuit 8 of the circuit A connected to the near point side electrode 6b on the side apart from the light projecting means 1. When the luminance of the light fed to the PSD 6 becomes high and the stationary light current is increased, the circuit 8 connected to the far point side electrode 6a can not perform a current removing action against the current of a fixed value or above, and it is set to the saturated state. |
