JPS55163952A - One-dimensional solid-state pickup unit - Google Patents

Abstract

PURPOSE:To make it possible to stabilize a black level which is unrelated to the quantity of incident light of an output signal, by gating part of the output signal obtained at constant intervals, by converting this signal into a DC current and then by supplying it to the input part of an electric charge transfer element. CONSTITUTION:The reference ''0'' level of the output signal of one-dimensional solid-state pickup element 1 supplied to clamping circuit 13 is clamped to a certain potential. Then, the reference black level is gated by gate circuit 14 with gate pulses from clock pulse generator 18 and a DC voltage corresponding to the level is integrating and holding circuit 15 and, after amplified 16, applied to the 2nd gate electrode 4 via terminal 10 of pickup element 1. On the other hand, since the 1st gate electrode 3 is applied with a constant voltage from reference voltage generating circuit 17 via terminal 9, a part, when changing in black level due to a change in temperature, is detected and the voltage applied to the 2nd gate electrode 4 changes to control the quantity of injected bias charge, thereby canceling the variation of dark current.