Display apparatus
A pixel circuit includes: a driving thin-film transistor including a 1a gate electrode, a 1b gate electrode, and a first semiconductor layer between the 1a gate electrode and the 1b gate electrode in a cross-sectional view; a storage capacitor including a first electrode electrically connected to the 1a gate electrode, and a second electrode spaced from the first electrode; a bias thin-film transistor including a 7a source-drain electrode electrically connected to the 1b gate electrode, and a 7b source-drain electrode configured to receive a bias voltage; and a light-emitting diode including an anode electrically connected to the driving thin-film transistor.
1 . A pixel circuit comprising:
a driving thin-film transistor comprising a first gate electrode, a second gate electrode, and a first semiconductor layer between the first gate electrode and the second gate electrode in a cross-sectional view;
a storage capacitor comprising a first electrode electrically connected to the first gate electrode, and a second electrode spaced from the first electrode;
a bias thin-film transistor comprising a first source-drain electrode configured to receive a bias voltage and a second source-drain electrode electrically connected to the second gate electrode;
a light-emitting diode comprising an anode electrically connected to the driving thin-film transistor; and
an initialization thin-film transistor connected to the first gate electrode of the driving thin-film transistor, the anode of the light-emitting diode, and an initialization voltage line configured to transmit an initialization voltage,
wherein the initialization thin-film transistor comprises a first gate electrode, a second gate electrode, and a second semiconductor layer between the first gate electrode of the initialization thin-film transistor and the second gate electrode of the initialization thin-film transistor in the cross-sectional view.
2 . The pixel circuit of claim 1 , wherein the bias thin-film transistor is configured to be turned on to apply the bias voltage to the second gate electrode of the driving thin-film transistor.
3 . The pixel circuit of claim 2 , wherein, when the bias voltage is applied to the second gate electrode of driving thin-film transistor, a threshold voltage of the driving thin-film transistor is shifted by the bias voltage.
4 . The pixel circuit of claim 3 , wherein the driving thin-film transistor comprises a p-type metal-oxide-semiconductor (pMOS) thin-film transistor, and the bias voltage is a positive voltage.
5 . The pixel circuit of claim 1 , wherein the second semiconductor layer of the initialization thin-film transistor comprises an oxide semiconductor.
6 . The pixel circuit of claim 1 , wherein a second source-drain electrode of the initialization thin-film transistor is electrically connected to the anode of the light-emitting diode.
7 . The pixel circuit of claim 6 , wherein the second source-drain electrode of the initialization thin-film transistor is electrically connected to the first electrode of the storage capacitor.
8 . The pixel circuit of claim 6 , wherein a first source-drain electrode of the initialization thin-film transistor is electrically connected to the initialization voltage line configured to transmit the initialization voltage.
9 . The pixel circuit of claim 6 , wherein the second source-drain electrode of the bias thin-film transistor is electrically connected to the second gate electrode of the initialization thin-film transistor.
10 . The pixel circuit of claim 9 , wherein the bias thin-film transistor is configured to be turned on to apply the bias voltage to the second gate electrode of the driving thin-film transistor and the second gate electrode of the initialization thin-film transistor, and wherein the initialization thin-film transistor is configured to be turned on by the bias voltage to initialize the anode.
11 . The pixel circuit of claim 9 , wherein the initialization thin-film transistor comprises an n-type metal-oxide-semiconductor (nMOS) thin-film transistor.
12 . The pixel circuit of claim 6 , wherein the initialization thin-film transistor comprises a pMOS thin-film transistor,
the bias thin-film transistor is configured to be turned on or turned off according to a control signal, and
the second gate electrode of the initialization thin-film transistor is configured to receive the control signal.
13 . The pixel circuit of claim 1 , wherein the second electrode of the storage capacitor is electrically connected to a power voltage line configured to transmit a power voltage, and
wherein the pixel circuit further comprising:
a switching thin-film transistor electrically connected to a first source-drain electrode of the driving thin-film transistor;
a first emission control thin-film transistor electrically connecting the power voltage line to the driving thin-film transistor; and
a second emission control thin-film transistor electrically connected between the anode and the driving thin-film transistor.
14 . A method of driving a pixel circuit, the pixel circuit comprising a driving thin-film transistor comprising a first gate electrode and a second gate electrode underneath the first gate electrode, a storage capacitor comprising a first electrode and a second electrode, and a light-emitting diode comprising an anode and configured to emit light according to a driving current received from the driving thin-film transistor, the method comprising:
shifting a threshold voltage of the driving thin-film transistor by applying a bias voltage to the second gate electrode of the driving thin-film transistor;
applying a driving voltage to the driving thin-film transistor; and
transmitting the driving current to the light-emitting diode based on the shifted threshold voltage and the driving voltage,
wherein the pixel circuit further comprises an initialization thin-film transistor connected to the first gate electrode of the driving thin-film transistor, the anode of the light-emitting diode, and an initialization voltage line configured to transmit an initialization voltage, and
wherein the initialization thin-film transistor comprises a first gate electrode, a second gate electrode, and a second semiconductor layer between the first gate electrode of the initialization thin-film transistor and the second gate electrode of the initialization thin-film transistor in a cross-sectional view.
15 . The method of claim 14 ,
wherein the initialization thin-film transistor comprises an n-type metal-oxide-semiconductor (nMOS) thin-film transistor,
wherein the second gate electrode of the initialization thin-film transistor is located underneath the first gate electrode of the initialization thin-film transistor, and
wherein the shifting of the threshold voltage comprises initializing the anode by applying the bias voltage concurrently to the second gate electrode of the driving thin-film transistor and the second gate electrode of the initialization thin-film transistor.
16 . The method of claim 14 , wherein the pixel circuit further comprises a bias thin-film transistor electrically connected to the second gate electrode of the driving thin-film transistor,
wherein the initialization thin-film transistor comprises a p-type metal-oxide-semiconductor (pMOS) thin-film transistor,
wherein the bias thin-film transistor is configured to be turned on or turned off according to a control signal, and
wherein the shifting of the threshold voltage comprises initializing the anode by applying the control signal to the second gate electrode of the initialization thin-film transistor.
17 . An electronic device comprising:
a display area comprising a plurality of sub-pixels, each of the sub-pixels comprising a light-emitting diode, and a pixel circuit configured to drive the light-emitting diode; and
a non-display area around the display area,
wherein the pixel circuit comprises:
a driving thin-film transistor comprising a first gate electrode, a second gate electrode, and a first semiconductor layer between the first gate electrode and the second gate electrode in a cross-sectional view;
a storage capacitor comprising a first electrode electrically connected to the first gate electrode of the driving thin-film transistor, and a second electrode spaced from the first electrode;
a bias thin-film transistor comprising a first source-drain electrode electrically connected to the second gate electrode of the driving thin-film transistor, and a second source-drain electrode configured to receive a bias voltage; and
an initialization thin-film transistor connected to the first gate electrode of the driving thin-film transistor and an initialization voltage line configured to transmit an initialization voltage,
wherein the light-emitting diode comprises an anode electrically connected to the driving thin-film transistor,
wherein the initialization thin-film transistor is connected to the anode of the light-emitting diode, wherein the initialization thin-film transistor comprises a first gate electrode, a second gate electrode, and a second semiconductor layer between the first gate electrode of the initialization thin-film transistor and the second gate electrode of the initialization thin-film transistor in the cross-sectional view, and
wherein the electronic device is one of a cellular phone or a television.
18 . The electronic device of claim 17 , wherein the bias thin-film transistor is configured to be turned on to apply the bias voltage to the second gate electrode of the driving thin-film transistor, and
wherein, when the bias voltage is applied to the second gate electrode of the driving thin-film transistor, a threshold voltage of the driving thin-film transistor is shifted by the bias voltage.