| 摘要 |
PURPOSE:To perform initial setting of storage time for a CCD photo sensor only with an electric circuit, by comparing a voltage converted in response to amount of light with a reference voltage, and initially setting the storage time of the photo sensor through the result of comparison. CONSTITUTION:A capacitor 17 for optical current charging starts charging, in detecting amount of light Q with a photo diode 16. An FF19 is set at the same time, and a storage time pulse outputted from a terminal TS is set to an H level and inputted to a sensor control circuit. When the potential of the capacitor 17 is higher than a reference voltage V1, a comparator 18 gives an output, the FF19 is reset, the storage time pulse is switched into an L level for the initial set of the storage time of the CCD photo sensor. A reference voltage obtained via a variable resistor 21 is arbitrarily changed, allowing to change the set value of the storage time, even if the amount of light detected with the photo diode 16 is the same amount. |
