Patent ID: 9609244
Date: 2017-03-28
CPC Classifications: G01J,H03F,H04N

Claim:
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.