Method for driving image pickup device, method for correcting digital signal, image pickup device, method for driving image capturing system, and image capturing system

摘要

There are provided a method for driving an image pickup device, a method for correcting a digital signal, an image pickup device, a method for driving an image capturing system, and an image capturing system. Digital signals are generated on the basis of a potential at an input node of a comparison unit by using a first reference signal whose potential changes by a first amount per unit time and a second reference signal whose potential changes by a second amount per unit time, the second amount being greater than the first amount. A correction value based on a difference in signal value between the digital signals is derived. A digital signal based on a pixel signal is corrected on the basis of the derived correction value.

主权项

1. A method for driving an image pickup device, the image pickup device comprising:
a pixel configured to output a pixel signal, and an analog-to-digital conversion unit configured to convert an analog signal into a digital signal, the analog-to-digital conversion unit comprising:
a comparison unit configured to output a comparison result signal obtained by comparing an analog signal with a reference signal whose potential changes with time, anda counting unit configured to generate a count value by counting a clock signal, the method comprising: generating, a first digital signal having the count value generated by the counting unit as a result of counting the clock signal during a period from when the counting unit starts counting the clock signal in response to a timing at which a potential of a first reference signal (Vr1) starts changing at the counting unit by a first amount per unit time, to when a signal value of the comparison result signal obtained by comparing a first test signal being the analog signal with the first reference signal changes; generating, a second digital signal having the count value generated by the counting unit as a result of counting the clock signal during a period from when the counting unit starts counting the clock signal in response to a timing at which a potential of a second reference signal (Vr2) starts changing at the counting unit by a second amount per unit time which is greater than the first amount, to when a signal value of the comparison result signal obtained by comparing the first test signal with the second reference signal changes; and generating, a third digital signal having the count value generated by the counting unit as a result of counting the clock signal during a period from when the counting unit starts counting the clock signal in response to a timing at which a potential of at least one of the first reference signal and the second reference signal starts changing, to when a signal value of the comparison result signal obtained by comparing a signal of the analog signal based on the pixel signal with at least one of the first reference signal and the second reference signal changes, wherein the third digital signal is corrected on the basis of the first digital signal and the second digital signal, so as to reduce an offset which is included in the third digital signal, and arises from a difference between the timing at which the potential of at least one of the first reference signal (Vr1) and the second reference signal (Vr2) starts changing with time, and the timing at which the counting unit starts counting the clock signal.