Circulating shift register and distance measuring device

Abstract

When a voltage signal corresponding to charges circulating a circulating shift register including charge transfer channels, which are arranged in a ring pattern, are read out from the shift register as a signal value, since clocks for circulating the charges have a very high frequency, it is difficult to operate an A/D converter in synchronism with such clocks, and a very expensive A/D converter must be used. In view of this problem, when the signal is read out, the clock frequency is lowered, and the voltage signal corresponding to the charges is converted into a digital value using an A/D converter that operates at low speed. When a distance measuring device is configured using the circulating shift register, charges corresponding to an image are shifted by the circulating shift register. In this case, since the shift efficiency is less than 100%, the amount of charges immediately after a non-charge portion decreases as they are shifted, and such charges form a false image. In order to solve this problem, the distance is calculated without using any charges immediately after the non-charge portion.

Dependencies are inferred from the claim text.