Semiconductor device and driving method thereof

摘要

A semiconductor device includes a photodiode, a first transistor, a second transistor, and a third transistor. The second transistor and the third transistor have a function of retaining a charge accumulated in a gate of the first transistor. In a period during which the second transistor and the third transistor are off, a voltage level of a voltage applied to a gate of the second transistor is set to be lower than a voltage level of a source of the second transistor and a voltage level of a drain of the second transistor, and a voltage level of a voltage applied to a gate of the third transistor is set to be lower than a voltage level of a source of the third transistor and a voltage level of a drain of the third transistor.

主权项

1. A semiconductor device comprising:
a photodiode; a first transistor; a second transistor; a third transistor; and a fourth transistor, wherein a first terminal of the photodiode is directly connected to a first terminal of the second transistor, wherein a second terminal of the second transistor is directly connected to a gate of the first transistor and a first terminal of the third transistor, wherein a first terminal of the first transistor is electrically connected to a first terminal of the fourth transistor, wherein in a first period, a charge corresponding to an amount of incident light to the photodiode is accumulated to the gate of the first transistor, wherein in a second period, the charge is retained in the gate of the first transistor by turning off the second transistor and the third transistor, and wherein in the second period, a voltage level of a gate of the second transistor is lower than a voltage level of the first terminal of the second transistor, a voltage level of the second terminal of the second transistor, and a voltage level of a second terminal of the photodiode, and a voltage level of a gate of the third transistor is lower than a voltage level of the first terminal of the third transistor and a voltage level of a second terminal of the third transistor.