| 摘要 |
PURPOSE:To ensure an optional control for the photoelectric conversion characteristcs of an image pickup device which is free from a blooming phenomenon, by setting the adverse bias voltage obtained at the beginning a charge storing period higher than the voltage obtained at the end of the charge storing period. CONSTITUTION:Two P type regions 22 and 23 which form a pn junction with an n type semiconductor substrate 15 and have different levels of junction depth are formed on said substrate 15. Then a photoelectric converting element 19 and a vertical shift register 10 are formed to the regions 22 and 23 respectively. In such a constitution, the large adverse bias voltage is held at the beginning of a charge storing period and then charged to the smaller voltage at a time point in mid course of the storing time. As a reuslt, the ratio of the stored charge quantity is compressed to the incident light volume in a certain region. Then this region is saturated. Therefore the range of incident light volume that is capable of image pickup is increased. In other words, the output video amplitude is suppressed down to the prescribed value even in case the contrast ratio of a subject is very large. Thus the white compression, white clipping, etc. is eliminated. |
