Thin film transistor substrate and organic light-emitting diode display apparatus

Patent metadata

Field	Value
Publication number	US-10147352-B2
Application number	US-201615004472-A
Country	US
Kind code	B2
Filing date	Jan 22, 2016
Priority date	Jun 25, 2015
Publication date	Dec 4, 2018
Grant date	Dec 4, 2018

Abstract

An organic light-emitting diode (OLED) display apparatus is provided. The OLED display apparatus includes a substrate, an initialization voltage line, a first thin film transistor (TFT) including an active layer. The initialization voltage line transmits an initialization voltage. The first thin film transistor (TFT) includes an active layer, a gate electrode, and an auxiliary gate electrode. The active layer is disposed on the substrate and includes a source region, a channel region, and a drain region. The gate electrode is disposed on the channel region. The auxiliary gate electrode is disposed on the gate electrode on a boundary between the channel region and the drain region. The voltage application electrode is disposed on the auxiliary gate electrode and is connected to the initialization voltage line and the auxiliary gate electrode.

First claim

What is claimed is:

1. An organic light-emitting diode (OLED) display apparatus comprising:
a substrate;
an initialization voltage line that transmits an initialization voltage;
a first thin film transistor (TFT) comprising an active layer, a gate electrode, and an auxiliary gate electrode, the active layer being disposed on the substrate and comprising a source region, a channel region, and a drain region, the gate electrode being disposed on the channel region, and the auxiliary gate electrode being disposed on the gate electrode on a boundary between the channel region and the drain region; and
a voltage application electrode disposed on the auxiliary gate electrode and connected to the initialization voltage line and the auxiliary gate electrode,
wherein the auxiliary gate electrode receives the initialization voltage being direct current (DC) voltage, and the gate electrode receives a TFT control voltage as a scan signal, the TFT control voltage being different from the initialization voltage.

2. The OLED display apparatus of claim 1 , wherein the auxiliary gate electrode is not disposed on a boundary between the channel region and the source region.

3. The OLED display apparatus of claim 1 , wherein the first TFT comprises a p-type transistor, and wherein the initialization voltage has a negative direct current (DC) voltage level.

4. The OLED display apparatus of claim 1 , further comprising:
a first gate insulating film that insulates the active layer and the gate electrode from each other, the first gate insulating film being disposed between the active layer and the gate electrode;
a second gate insulating film that insulates the gate electrode and the auxiliary gate electrode from each other, the second gate insulating film being disposed between the gate electrode and the auxiliary gate electrode; and
an interlayer insulating film disposed between the auxiliary gate electrode and the voltage application electrode, wherein a first contact plug connecting the auxiliary gate electrode to the voltage application electrode is disposed in the interlayer insulating film.

5. The OLED display apparatus of claim 4 , further comprising:
a scan line that transmits the scan signal;
a data line and a driving voltage line which intersect the scan line and transmit a data signal and a driving voltage, respectively;
a switching TFT connected to the scan line and the data line;
a driving TFT comprising a source connected to a drain of the switching TFT, a gate connected to the source region of the first TFT, and a drain connected to the drain region of the first TFT; and
a storage capacitor comprising a lower electrode connected to the gate of the driving TFT and an upper electrode connected to the driving voltage line.

6. The OLED display apparatus of claim 5 , wherein the driving TFT is disposed between the first gate insulating film and the second gate insulating film, and wherein the driving TFT comprises a driving gate electrode functioning as the gate of the driving TFT and the lower electrode of the storage capacitor.

7. The OLED display apparatus of claim 5 , wherein the lower electrode is disposed between the first gate insulating film and the second gate insulating film, and wherein the upper electrode is disposed between the second gate insulating film and the interlayer insulating film.

8. The OLED display apparatus of claim 5 , wherein the gate electrode of the first TFT is connected to the scan line, wherein the first TFT is turned on in response to the scan signal and compensates for a threshold voltage of the driving TFT.

9. The OLED display apparatus of claim 5 , further comprising an initialization TFT that is turned on in response to a previous scan signal transmitted via a previous scan line, and transmits the initialization voltage to the gate of the driving TFT.

10. The OLED display apparatus of claim 5 , further comprising:
an OLED connected to the drain of the driving TFT and emitting light in response to a driving current output from the driving TFT;
an operation control TFT that is turned on in response to an emission control signal transmitted via an emission control line and transmits the driving voltage to the driving TFT; and
an emission control TFT that is turned on in response to the emission control signal and transmits the driving current from the driving TFT to the OLED.

11. The OLED display apparatus of claim 10 , further comprising a bypass TFT that is turned on in response to a bypass control signal transmitted via a bypass control line and transmits the initialization voltage to an anode of the OLED.

12. The OLED display apparatus of claim 5 , wherein the initialization voltage line intersects the scan line, and wherein the initialization voltage line is disposed in a same layer as the data line and the driving voltage line.

13. A thin film transistor (TFT) substrate comprising:
a substrate;
an active layer disposed on the substrate and comprising a source region, a channel region, and a drain region;
a gate electrode disposed on the channel region, the gate electrode receiving a TFT control voltage as a scan signal;
an auxiliary gate electrode disposed on the gate electrode on a boundary between the channel region and the drain region; and
a voltage application electrode disposed on the auxiliary gate electrode and connected to the auxiliary gate electrode, wherein the voltage application electrode receives an initialization voltage being direct current (DC) voltage, the initialization voltage being different from the TFT control voltage.

14. The TFT substrate of claim 13 , further comprising:
a first gate insulating film that insulates the active layer and the gate electrode from each other, the first gate insulating film being disposed between the active layer and the gate electrode;
a second gate insulating film that insulates the gate electrode and the auxiliary gate electrode from each other, the second gate insulating film being disposed between the gate electrode and the auxiliary gate electrode; and
an interlayer insulating film disposed between the auxiliary gate electrode and the voltage application electrode, wherein the auxiliary gate electrode is connected to the voltage application electrode through a first contact plug disposed in the interlayer insulating film.

15. The TFT substrate of claim 14 , further comprising:
a source electrode disposed on the interlayer insulating film, wherein the source electrode is connected to the source region through a second contact plug disposed in the first gate insulating film, the second gate insulating film and the interlayer insulating film; and
a drain electrode disposed on the interlayer insulating film, wherein the drain electrode is connected to the drain region through a third contact plug disposed in the first gate insulating film, the second gate insulating film and the interlayer insulating film, and
wherein the source electrode, the drain electrode, and the voltage application electrode comprise a same material.

16. The TFT substrate of claim 13 , wherein the auxiliary gate electrode is not disposed on a boundary between the channel region and the source region.

17. The TFT substrate of claim 13 , wherein the initialization voltage has a negative direct current (DC) voltage level, and wherein the source region and the drain region comprise p-type impurities.

18. An organic light-emitting diode (OLED) display apparatus comprising:
a substrate;
a scan line that transmits a scan signal;
an initialization voltage line that transmit

Assignees

• Samsung Display Co Ltd

Inventors

• Yoon Juwon
• Son Sewan
• Lee Iljeong
• Lee Jiseon
• Ji Deukmyung

Classifications

• G09G2300/0819

  used for counteracting undesired variations, e.g. feedback or autozeroing · CPC title

• G09G2320/0214

  with crosstalk due to leakage current of pixel switch in active matrix panels · CPC title

• G09G2300/0866

  by means of changes in the pixel supply voltage · CPC title

• G09G3/3233 Primary

  with pixel circuitry controlling the current through the light-emitting element · CPC title

• G09G2300/0842

  forming a memory circuit, e.g. a dynamic memory with one capacitor · CPC title