IT CCD Imaging Sensor With Variable Speed Electronic Shutter

Abstract

The Hole-Accumulation Diode-Sensor (HAD-Sensor) structure, which allows to implement the variable speed electronic shutter in the Interline Transfer (IT) CCD imaging sensor, has been developed. Based on this technology, a 2/3 inch imaging sensor with 420,000 picture elements for consumer, industrial, and professional use was manufactured. The theoretical lower limit of variable shutter speed is about 1/1,000,000 sec. in the case of exposure within the vertical blanking interval (i.e. below 1/787 sec.). This HAD-Sensor achieves the following five major results, which are essential to yield the variable speed electronic shutter in an IT CCD: ( 1 ) complete draining of unwanted stored charges into n-type substrate, ( 2 ) negligibly small lag, ( 3 ) dark current reduced to 1/10 of the conventional level, ( 4 ) smear reduced to 1/5 of the conventional level, and ( 5 ) increased blue sensitivity.