| 摘要 |
PURPOSE:To make it possible for an MOS image pickup element to detect a very weak signal by reducing the generation of a fixed pattern noise by holding scanning pulses at a constant voltage. CONSTITUTION:Individual scanning pulses, differing in voltage, obtained from respective terminals 31-34 of the scanning pulse generating method are shaped by constant-voltage control circuit 9 to a constant scanning pulse voltage, thereby reducing fixed pattern noises of the solid-state image pickup element. In constant voltage control circuit 9, units 9a-9d are composed of MOST switches having threshold voltage VT and all gates are connected to terminal 91 in common and applied with constant control voltage 91V. Therefore, if the above-mentioned even pulse voltages 31V-34V are all greater than 91V-VT, scanning voltages appearing at terminals 31'-34' are constant pulse voltage (a) determined by 91V-VT according to general characteristics of MOST switches. |
