| 摘要 |
PURPOSE:To obtain a reproduced picture having a high contrast, by subtracting the register output of a non-output period from the register output of an output period of a charge transfer register to obtain picture signals and therefore offsetting the dark current level voltage. CONSTITUTION:A reset transistor (TR) f2 of an output circuit 62 is turned on in a false transfer period, and a charge storing region 52 is set at constant voltage VDD. Then an output gate electrode is turned on to lead the charge produced by the dark current which is transferred by charge transfer registers 2 and 3 into the region 52. Thus the voltage V0 of the dark current level is obtained at a load resistance R2 of a TR e2. This voltage is turned into the output voltage Vout2 of the circuit 62 and transferred in an optical charge transfer period. By this period, the optical charge produced at each photoelectric converting element (a) is transferred through the registers 2 and 3. Then the optical charge is led into a charge storing region 51 and added with the voltage corresponding to the level V0 and the photoelectric quantity through an output circuit 61. Thus the output voltage Vout1 is obtained. The voltage Vout2 is subtracted from the voltage Vout1 through a differential amplifier 7. Thus a picture signal Vout3 which receives no effect of the level V0 is obtained. |
