Imaging device
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorsSeiichi Yoneda, Yusuke Negoro
Life of this patent
Estimating the term…
Abstract
An imaging device capable of taking an image in both a dark environment and a bright environment in a light amount range equivalent to or greater than that of human vision is desired. A wide dynamic range and high image quality are achieved. In order to obtain an image with a widened dynamic range, two capacitors, a large capacitor and a small capacitor, are provided in one pixel. The large capacitor is formed to be interposed between a transistor for controlling the amount of charge overflowed from the small capacitor and a transistor for resetting accumulated charge, and OS transistors are used as these two transistors. The OS transistor has extremely low off-state current characteristics, and thus can widen the dynamic range of imaging.
Claims9
An imaging device comprising a first transistor to a sixth transistor, a photoelectric conversion element, a first capacitor, and a second capacitor,
- wherein one electrode of the photoelectric conversion element is electrically connected to one of a source and a drain of the first transistor,
- wherein the other of the source and the drain of the first transistor is electrically connected to a source and a drain of the second transistor,
- wherein the other of the source and the drain of the first transistor is electrically connected to one electrode of the first capacitor,
- wherein the other of the source and the drain of the first transistor is electrically connected to a gate electrode of the third transistor,
- wherein one of a source and a drain of the third transistor is electrically connected to one of a source and a drain of the fourth transistor,
- wherein the other of the source and the drain of the second transistor is electrically connected to one electrode of the second capacitor,
- wherein the one electrode of the second capacitor is electrically connected to one of a source and a drain of the fifth transistor,
- wherein the other of the source and the drain of the fifth transistor is electrically connected to a wiring to which a constant potential is supplied,
- wherein the fifth transistor is a reset transistor,
- wherein one of a source and a drain of the sixth transistor is electrically connected to the one of the source and the drain of the first transistor,
- wherein the first transistor, the third transistor, the fourth transistor, and the sixth transistor each comprise silicon in a region where a channel is formed, and
- wherein the second transistor and the fifth transistor each comprise an oxide semiconductor in a region where a channel is formed.
An imaging device comprising a first transistor to a sixth transistor, a photoelectric conversion element, a first capacitor, and a second capacitor,
- wherein one electrode of the photoelectric conversion element is directly connected to one of a source and a drain of the first transistor,
- wherein the other of the source and the drain of the first transistor is directly connected to a source and a drain of the second transistor,
- wherein the other of the source and the drain of the first transistor is directly connected to one electrode of the first capacitor,
- wherein the other of the source and the drain of the first transistor is directly connected to a gate electrode of the third transistor,
- wherein one of a source and a drain of the third transistor is directly connected to one of a source and a drain of the fourth transistor,
- wherein the other of the source and the drain of the second transistor is directly connected to one electrode of the second capacitor,
- wherein the one electrode of the second capacitor is directly connected to one of a source and a drain of the fifth transistor,
- wherein the other of the source and the drain of the fifth transistor is electrically connected to a wiring to which a constant potential is supplied,
- wherein the fifth transistor is a reset transistor,
- wherein one of a source and a drain of the sixth transistor is directly connected to the one of the source and the drain of the first transistor,
- wherein the first transistor, the third transistor, the fourth transistor, and the sixth transistor each comprise silicon in a region where a channel is formed, and
- wherein the second transistor and the fifth transistor each comprise an oxide semiconductor in a region where a channel is formed.
An imaging device comprising a first transistor to a sixth transistor, a photoelectric conversion element, a first capacitor, and a second capacitor,
- wherein one electrode of the photoelectric conversion element is directly connected to one of a source and a drain of the first transistor,
- wherein the other of the source and the drain of the first transistor is directly connected to a source and a drain of the second transistor,
- wherein the other of the source and the drain of the first transistor is directly connected to one electrode of the first capacitor,
- wherein the other of the source and the drain of the first transistor is directly connected to a gate electrode of the third transistor,
- wherein one of a source and a drain of the third transistor is directly connected to one of a source and a drain of the fourth transistor,
- wherein the other of the source and the drain of the second transistor is directly connected to one electrode of the second capacitor,
- wherein the one electrode of the second capacitor is directly connected to one of a source and a drain of the fifth transistor,
- wherein the other of the source and the drain of the fifth transistor is electrically connected to a wiring to which a constant potential is supplied,
- wherein the fifth transistor is a reset transistor,
- wherein one of a source and a drain of the sixth transistor is directly connected to the one of the source and the drain of the first transistor, and
- wherein the second transistor and the fifth transistor each comprise an oxide semiconductor in a region where a channel is formed.
Dependencies are inferred from the claim text.