| 摘要 |
PURPOSE:To attain correct automatic gain control by providing charge storage section for compensation of almost same shape as a substantial charge storage section and detecting a charge stored in it to form a reference voltage thereby detecting correct zero level of an output voltage. CONSTITUTION:Since the charge stored in a floating spread region 5 by an optical current generated in a photo diode 2 represents an average value of a signal charge of photosensitive picture elements 7-1-7-6, automatic gain control is attained independently of the luminous intensity by detecting an output of a source follower circuit 11 reading the potential of this floating diffusion region 5. A photo diode 22 for compensation not generating an optical current is provided and an output voltage of a source follower circuit 211 for compensation being this output is brought into zero level to detect the output voltage of the source follower circuit 11. Then the output voltage in which the dark current component of the photo diode 2 is compensated is obtained. |
