Solid-state image pickup device

Abstract

Abstract PURPOSE:To smoothly change the level of a picture signal by always expanding or shortening the photoelectric conversion period of a solid-state image pickup element in a certain proportion to control the exposure. CONSTITUTION:A timing BT generating circuit T' is operated by the output of a comparing circuit C, and the output of an up/down counter 20 is decoded to binary data expanded or Shortened in a certain proportion by a decoder 21. Meanwhile, a step counter 22 is reset by a vertical scanning line signal VD and is counted up in the photoelectric conversion period by a clock signal CK having a cycle of 16 pulses per a vertical scanning line period V; and when the output coincides with binary data of the decoder output during this counting-up, an AND gate 24 outputs a discharge driving timing BT to a driving circuit D. Consequently, the photoelectric conversion period is shortened or expanded in the certain proportion each time when the up/down counter 20 is counted up. Thus, the level of the picture signal obtained from a solid-state image pickup element S is smoothly changed.

Inventors

• 👤 Yoshihito Higashitsutsumi
• 👤 良仁 東堤

Bibliographic Details