Patent ID: 11971641
Assignee: SHARP DISPLAY TECHNOLOGY CORPORATION
Field: Optics (Instruments)
Classification: CPC G  H | IPC G  H

Claim 18:
19. An active matrix substrate provided with a display region defined by a plurality of pixel regions, the active matrix substrate comprising:
a substrate;
a first thin film transistor (TFT) supported by the substrate and disposed on each of the plurality of pixel regions;
a first flattened layer covering the first TFT; and
a pixel electrode provided on the first flattened layer and electrically connected to the first TFT,
wherein the first TFT includes:
a lower gate electrode provided on the substrate,
a lower gate insulating layer covering the lower gate electrode,
an oxide semiconductor layer provided on the lower gate insulating layer, the oxide semiconductor layer including a channel region facing the lower gate electrode with the lower gate insulating layer interposed between the channel region and the lower gate electrode, and a source contact region and a drain contact region positioned respectively at either sides of the channel region,
an upper gate insulating layer provided on the channel region of the oxide semiconductor layer, and
an upper gate electrode provided on the upper gate insulating layer and facing the channel region of the oxide semiconductor layer with the upper gate insulating layer interposed between the channel region and the upper gate electrode, wherein
the active matrix substrate further comprises:
a first connection electrode configured to electrically connect the drain contact region of the oxide semiconductor layer and the pixel electrode,
the first flattened layer includes a pixel contact hole formed, such that to partially expose the first connection electrode,
a bottom face of the pixel contact hole at least partially overlaps, of a lower gate metal layer including the lower gate electrode and an upper gate metal layer including the upper gate electrode, at least the lower gate metal layer when viewed from a normal direction of the substrate, and
the first connection electrode is formed from a transparent conductive material,
wherein the active matrix substrate further comprises:
a second connection electrode formed from a transparent conductive material and electrically connecting the first connection electrode and the pixel electrode, the second connection electrode being in contact with the first connection electrode in the pixel contact hole; and
a second flattened layer filling the pixel contact hole and partially covering the second connection electrode,
wherein the pixel electrode is in contact with a portion of the second connection electrode which is not covered by the second flattened layer, and
a portion of the pixel electrode is on the second flattened layer.