Organic light emitting diode display device including vertically stacked electrodes on driving transistor
An organic light emitting diode display includes a driving transistor and a compensation transistor. The driving transistor includes a first gate electrode disposed on a substrate, a polycrystalline semiconductor layer disposed on the first gate electrode of the driving transistor and including a first electrode, a second electrode, and a channel, and a second gate electrode disposed on the polycrystalline semiconductor layer of the driving transistor. The compensation transistor includes a polycrystalline semiconductor layer including a first electrode, a second electrode, and a channel, and a gate electrode disposed on the polycrystalline semiconductor layer of the compensation transistor.
1 . An organic light emitting diode display, comprising:
a data line;
a driving voltage line transmitting a driving voltage;
an organic light emitting element;
a first transistor electrically connected between the driving voltage line and the organic light emitting element;
an overlapping layer; and
a second electrode,
wherein:
the first transistor includes:
a first semiconductor layer having a first channel of the first transistor; and
a first gate electrode overlapping and disposed under the first channel of the first transistor,
the overlapping layer and the second electrode overlap the first channel of the first transistor in a vertical direction,
the overlapping layer and the second electrode receive the driving voltage, and
the first gate electrode of the first transistor has a voltage level varying in order to control a brightness of the organic light emitting element.
2 . The organic light emitting diode display of claim 1 , further comprising a second transistor electrically connected between the data line and the first transistor, and wherein the first semiconductor layer further includes:
a first part disposed in the first semiconductor layer and on a first side of the first channel of the first transistor; and
a second part disposed in the first semiconductor layer and on a second side of the first channel of the first transistor.
3 . The organic light emitting diode display of claim 2 , wherein the first part of the first transistor is electrically connected to the driving voltage line, and the second part of the first transistor outputs a current to the organic light emitting element.
4 . The organic light emitting diode display of claim 3 , wherein the second transistor includes:
a second semiconductor layer having a second channel of the second transistor; and
a second gate electrode overlapping the second channel of the second transistor.
5 . The organic light emitting diode display of claim 4 , wherein the second semiconductor layer further includes:
a first second part disposed in the second semiconductor layer and on a first side of the second channel of the second transistor; and
a second second part disposed in the second semiconductor layer and on a second side of the second channel of the second transistor.
6 . The organic light emitting diode display of claim 5 , wherein the first second part of the second transistor is electrically connected to the data line, and the second second part of the second transistor is electrically connected to the first part of the first transistor.
7 . The organic light emitting diode display of claim 6 , wherein the second second part of the second transistor is directly connected to the first part of the first transistor.
8 . The organic light emitting diode display of claim 6 , further comprising:
a third transistor electrically connected between the first gate electrode of the first transistor and the second part of the first transistor.
9 . The organic light emitting diode display of claim 8 , wherein the third transistor includes:
a third semiconductor layer having a third channel of the third transistor; and
a third gate electrode overlapping the third channel of the third transistor.
10 . The organic light emitting diode display of claim 9 , wherein the third semiconductor layer further includes:
a first third part disposed in the third semiconductor layer and on a first side of the third channel of the third transistor; and
a second third part disposed in the third semiconductor layer and on a second side of the third channel of the third transistor.
11 . The organic light emitting diode display of claim 10 , wherein the first third part of the third transistor is electrically connected to the second part of the first transistor, and
the second third part of the third transistor is electrically connected to the first gate electrode of the first transistor.
12 . The organic light emitting diode display of claim 11 , further comprising a connection electrode which connects the first gate electrode of the first transistor and the second third part of the third transistor.
13 . The organic light emitting diode display of claim 12 , wherein the first third part of the third transistor is directly connected to the second part of the first transistor.
14 . The organic light emitting diode display of claim 12 , further comprising:
a third electrode; and
a fourth electrode,
wherein the third electrode overlaps the second channel of the second transistor in a vertical direction, and
the fourth electrode overlaps the third channel of the third transistor in a vertical direction.
15 . The organic light emitting diode display of claim 14 , wherein:
the second gate electrode of the second transistor is disposed over the second semiconductor layer,
the third gate electrode of the third transistor is disposed over the third semiconductor layer,
the third electrode is disposed under the second channel of the second transistor, and
the fourth electrode is disposed under the third channel of the third transistor.
16 . The organic light emitting diode display of claim 15 , wherein the third electrode and the fourth electrode are electrically connected to each other.
17 . The organic light emitting diode display of claim 12 , wherein:
the second gate electrode of the second transistor is disposed under the second semiconductor layer, and
the third gate electrode of the third transistor is disposed under the third semiconductor layer.
18 . The organic light emitting diode display of claim 12 , further comprising:
an initialization voltage line; and
a fourth transistor electrically connected between the first gate electrode of the first transistor and the initialization voltage line.
19 . The organic light emitting diode display of claim 18 , wherein the fourth transistor includes:
a fourth semiconductor layer having a fourth channel of the fourth transistor; and
a fourth gate electrode overlapping the fourth channel of the fourth transistor.
20 . The organic light emitting diode display of claim 19 , wherein the fourth semiconductor layer further includes:
a first fourth part disposed in the fourth semiconductor layer and on a first side of the fourth channel of the fourth transistor; and
a second fourth part disposed in the fourth semiconductor layer and on a second side of the fourth channel of the fourth transistor.
21 . The organic light emitting diode display of claim 20 , wherein the first fourth part of the fourth transistor is electrically connected to the initialization voltage line, and
the second fourth part of the fourth transistor is electrically connected to the first gate electrode of the first transistor.
22 . The organic light emitting diode display of claim 21 , wherein:
the fourth gate electrode of the fourth transistor is disposed over the fourth semiconductor layer.
23 . The organic light emitting diode display of claim 21 , wherein the second fourth part of the fourth transistor and the first gate electrode of the first transistor are connected each other by the connection electrode.
24 . The organic light emitting diode display of claim 1 , wherein the overlapping layer is disposed under the first channel of the first transistor, and
the second electrode is disposed over the first channel of the first transistor.