Photodetector having a first transistor with a channel formed in an oxide semiconductor layer and method for driving photodetector

摘要

Adverse effects of noise are reduced. A photodetector circuit, a difference data generation circuit, and a data input selection circuit are included. The photodetector circuit has a function of generating an optical data signal. A first data signal and a second data signal is input to the difference data generation circuit and the difference data generation circuit has a function of generating difference data of data of the first data signal and data of the second data signal. The data input selection circuit has a function of determining that the data of optical data signal is regarded as data of the first data signal or data of the second data signal.

主权项

1. A photodetector comprising:
a difference data generation circuit; a photoelectric conversion element; a first transistor; a second transistor; and a third transistor, wherein one of a source and a drain of the first transistor is electrically connected to the photoelectric conversion element, wherein one of a source and a drain of the second transistor is electrically connected to the photoelectric conversion element, wherein the other of the source and the drain of the first transistor is electrically connected to a gate of the third transistor, wherein the other of the source and the drain of the second transistor is electrically connected to the gate of the third transistor, wherein one of a source and a drain of the third transistor is electrically connected to a first input terminal of the difference data generation circuit, wherein the first transistor comprises an oxide semiconductor layer in which a channel is formed, wherein the third transistor comprises a region in which a channel is formed, wherein the oxide semiconductor layer is over an insulating layer, and wherein the region is under the insulating layer.