Thin film transistor substrate and display device

1. A thin film transistor substrate comprising:

a substrate;

a thin film transistor having, over the substrate, a gate electrode, a gate insulating film, an oxide semiconductor layer, and a source-drain electrode in order; and

a capacitor having, over the substrate, a bottom electrode, a capacitor insulating film, and a top electrode made of oxide semiconductor in order,

wherein,

the top electrode has a contact region which is in contact with the source-drain electrode, and the source-drain electrode is not formed in a region other than the contact region of the top electrode.

2. A thin film transistor substrate comprising:

a substrate;

a thin film transistor having, over the substrate, a gate electrode, a gate insulating film, an oxide semiconductor layer, and a source-drain electrode in order;

a capacitor having, over the substrate, a bottom electrode, a capacitor insulating film, and a top electrode made of oxide semiconductor in order; and

a passivation film covering the thin film transistor and the capacitor, the passivation film having an opening in correspondence with the top electrode in the capacitor.

3. A display device comprising a display element in a thin film transistor substrate,

wherein the thin film transistor substrate includes:

a substrate;

a thin film transistor having, over the substrate, a gate electrode, a gate insulating film, an oxide semiconductor layer, and a source-drain electrode in order; and

a capacitor having, over the substrate, a bottom electrode, a capacitor insulating film, and a top electrode made of oxide semiconductor in order, and wherein,

the display element is an organic light emitting element having an organic layer including a light emission layer, between an anode and a cathode, and the top electrode in the capacitor is connected to the anode or the cathode.

4. A display device comprising a display element in a thin film transistor substrate,

wherein the thin film transistor substrate includes:

a substrate;

a thin film transistor having, over the substrate, a gate electrode, a gate insulating film, an oxide semiconductor layer, and a source-drain electrode in order;

a capacitor having, over the substrate, a bottom electrode, a capacitor insulating film, and a top electrode made of oxide semiconductor in order; and

a display region having the display element, and a drive unit, and wherein,

the display region includes scan lines as rows, signal lines as columns, pixels made by the display elements each disposed in a part where the scan line and the signal line intersect, and power source lines disposed in correspondence with rows of the pixels,

the drive unit includes a write scanner for sequentially supplying control signals to the scan lines and line-sequentially scanning the pixels on a row unit basis, a power scanner for supplying a power source voltage to the power source lines in accordance with the line-sequential scan, and a signal selector for supplying a signal potential which becomes a video signal to the signal line in accordance with the line-sequential scan,

the pixel includes the display element, a sampling transistor made by the thin film transistor, a drive transistor made by the thin film transistor, and a storage capacitor made by the capacitor,

a gate of the sampling transistor is connected to the scan line, one of a source and a drain of the sampling transistor is connected to the signal line, and the other is connected to a gate of the drive transistor,

one of a source and a drain of the drive transistor is connected to the display element, and the other is connected to the power source line, and

the bottom electrode of the capacitor configuring of the storage capacitor is connected to the gate of the drive transistor.