Liquid crystal display device
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorsHajime Kimura, Hideki Uochi
Life of this patent
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Abstract
It is an object of the present invention to apply a sufficient electrical field to a liquid crystal material in a horizontal electrical field liquid crystal display device typified by an FFS type. In a horizontal electrical field liquid crystal display, an electrical field is applied to a liquid crystal material right above a common electrode and a pixel electrode using plural pairs of electrodes rather than one pair of electrodes. One pair of electrodes includes a comb-shaped common electrode and a comb-shaped pixel electrode. Another pair of electrodes includes a common electrode provided in a pixel portion and the comb-shaped pixel electrode.
Claims4
A liquid crystal display device having a liquid crystal layer provided over a pixel electrode and a common electrode comprising:
- a semiconductor layer electrically connected to the pixel electrode and having a channel formation region of a transistor;
- a gate line over the semiconductor layer;
- a first insulating layer over the gate line;
- a source line over the first insulating layer and electrically connected to the semiconductor layer;
- a first conductive layer over the first insulating layer and electrically connected to the semiconductor layer and the pixel electrode;
- and
- a common wiring over the first insulating layer and electrically connected to the common electrode,
- wherein the first conductive layer has a same material as the source line,
- wherein the semiconductor layer comprises silicon,
- wherein each of the pixel electrode and the common electrode comprises indium tin oxide,
- wherein the common electrode is in contact with an upper surface of the common wiring,
- wherein in a plan view, the common wiring is disposed on a side of another adjacent pixel in a direction intersecting a direction in which the common wiring extends, and does not overlap with the first conductive layer,
- wherein in a plan view, the channel formation region of the transistor does not overlap with the common electrode,
- wherein in a plan view, the pixel electrode has a comb-shape,
- wherein in a plan view, the common electrode has an opening,
- wherein the opening of the common electrode has a first region overlapping with the pixel electrode and a second region not overlapping with the pixel electrode, and
- wherein the common wiring overlaps with the second region.
A liquid crystal display device having a liquid crystal layer provided over a pixel electrode and a common electrode comprising:
- a semiconductor layer electrically connected to the pixel electrode and having a channel formation region of a transistor;
- a gate line over the semiconductor layer;
- a first insulating layer over the gate line;
- a source line over the first insulating layer and electrically connected to the semiconductor layer;
- a first conductive layer over the first insulating layer and electrically connected to the semiconductor layer and the pixel electrode;
- and
- a common wiring over the first insulating layer and electrically connected to the common electrode,
- wherein the first conductive layer has a same material as the source line,
- wherein the semiconductor layer comprises silicon,
- wherein each of the pixel electrode and the common electrode comprises indium tin oxide,
- wherein the common electrode is in contact with an upper surface of the common wiring,
- wherein in a plan view, the common wiring is disposed on a side of another adjacent pixel in a direction intersecting a direction in which the common wiring extends, and does not overlap with the first conductive layer,
- wherein in a plan view, the channel formation region of the transistor does not overlap with the common electrode,
- wherein in a plan view, the pixel electrode has a comb-shape,
- wherein in a plan view, the common electrode has a planar region, and a first region and a second region that are separated from each other,
- wherein a third region sandwiched between the first region and the second region has a fourth region that overlaps with the pixel electrode and a fifth region that does not overlap with the pixel electrode, and
- wherein the common wiring overlaps with the fifth region.
Dependencies are inferred from the claim text.