Organic light emitting display device and driving method for the same

Patent metadata

Field	Value
Publication number	US-11289028-B2
Application number	US-202017116512-A
Country	US
Kind code	B2
Filing date	Dec 9, 2020
Priority date	Dec 24, 2019
Publication date	Mar 29, 2022
Grant date	Mar 29, 2022

Abstract

The present disclosure describes an organic light emitting display device including: a display panel including data lines, gate lines, emission lines, and pixels, a data driver applying data signals to the data lines, and a gate driver applying gate signals and emission signals to the gate lines and the emission lines, respectively. At least one of the pixels may be operated in a first period in which a data voltage is applied, a second period in which the data voltage is remained and a driving current is provided according to the data voltage, and a third period in which the data voltage is remained and light emitting is not performed, where a ratio between lengths of the second and third periods can be adjusted. The at least one pixel may receive a preset voltage in the second period and the third period.

First claim

What is claimed is:

1. An organic light emitting display device comprising:
a display panel including a plurality of data lines, a plurality of gate lines, a plurality of emission lines, and a plurality of pixels;
a data driver applying data signals to the plurality of data lines;
a gate driver applying gate signals and emission signals to the plurality of gate lines and the plurality of emission lines, respectively; and
a timing controller controlling the data driver and the gate driver;
a first transistor providing a driving current from a first node to a third node according to a voltage in a second node;
a second transistor having a gate electrode, a first electrode, and a second electrode connected to a first gate line of the plurality of gate lines, one of the plurality of data lines, and the first node, respectively;
a third transistor having a gate electrode, a first electrode, and a second electrode connected to a second gate line of the plurality of gate lines, the third node, and the second node, respectively, and allowing a threshold voltage of the first transistor to be applied to the second node in a first period while a first gate signal with a turn-on voltage level is applied to the second transistor through the first gate line; and
a fourth transistor having a gate electrode, a first electrode, and a second electrode connected to the second gate line, a fourth node, and the first node, respectively, and allowing a preset voltage to be applied to the first node when the fourth transistor is turned on,
wherein the third transistor and the fourth transistor operate together by a second gate signal through the second gate line,
wherein at least one pixel of the plurality of pixels operates in the first period in which a data voltage is applied, a second period in which the data voltage is remained and the driving current is provided according to the data voltage, and a third period in which the data voltage is remained and light emitting is not performed, and
wherein a ratio between a length of the second period and a length of the third period is adjusted, and the at least one pixel receives the preset voltage in the second period and the third period.

2. The organic light emitting display device according to claim 1 , wherein the preset voltage is provided to the first node of the at least one pixel in the second period and the third period.

3. The organic light emitting display device according to claim 2 , further comprising:
a storage capacitor which includes a first electrode connected to the first node and a second electrode connected to the second node, wherein the data voltage is applied to the first electrode of the storage capacitor through the first node and the threshold voltage of the first transistor is applied to the second electrode of the storage capacitor through the second node, in the first period; and
an organic light emitting diode to which the driving current is provided in the second period and is not provided in the third period.

4. The organic light emitting display device according to claim 3 , wherein the at least one pixel comprises:
a fifth transistor providing the driving current to the organic light emitting diode in the second period,
wherein the second transistor provides the data voltage to the first node in the first period, and
wherein the fourth transistor provides the preset voltage to the first node in the third period.

5. The organic light emitting display device according to claim 4 , further comprising:
a sixth transistor providing the preset voltage to an anode electrode of the organic light emitting diode in the first period.

6. The organic light emitting display device according to claim 5 , further comprising:
a seventh transistor providing the preset voltage to the third node connected to a second electrode of the first transistor in the first period when driving current flows from a first electrode of the first transistor to the second electrode of the first transistor.

7. The organic light emitting display device according to claim 4 , wherein the second transistor is turned on in the first period by receiving a gate signal and turned off in the second period and the third period,
wherein the fourth transistor is turned off in the first period by receiving the gate signal and turned on in the second period and the third period, and
wherein the fifth transistor is turned off in the first period and the third period by receiving the emission signal and turned on in the second period.

8. The organic light emitting display device according to claim 7 , wherein the third transistor or the fourth transistor includes an oxide semiconductor.

9. The organic light emitting display device according to claim 2 , further comprising:
a storage capacitor which includes a first electrode connected to the fourth node providing the preset voltage and a second electrode connected to the second node, wherein the data voltage is applied to the first electrode of the storage capacitor through the fourth node and the threshold voltage of the first transistor is applied to the second electrode of the storage capacitor through the second node, in the first period; and
an organic light emitting diode to which the driving current is provided in the second period and is not provided in the first period and the third period.

10. The organic light emitting display device according to claim 9 , further comprising:
a fifth transistor applying the driving current to the organic light emitting diode in the second period,
wherein the second transistor provides the data voltage to the first node in the first period,
wherein the third transistor provides the preset voltage to the first node in the third period, and
wherein the fourth transistor applies the data voltage and the threshold voltage of the first transistor to the second node in the first period.

11. The organic light emitting display device according to claim 10 , further comprising:
a sixth transistor providing an initialization voltage to the third node in an initialization period; and
a seventh transistor providing the initialization voltage to an anode electrode of the organic light emitting diode in the initialization period.

12. The organic light emitting display device according to claim 10 , wherein the second transistor is turned on in the first period by receiving the first gate signal and turned off in the second period and the third period,
wherein the third transistor is turned off in the first period by receiving the second gate signal and turned on in the second period and the third period,
wherein the fourth transistor is turned on in the first period by receiving the second gate signal and turned off in the second period and the third period, and
wherein the fifth transistor is turned off in the first period and the third period by receiving an emission signal and turned on in the second period.

13. The organic light emitting display device according to claim 12 , wherein the fourth transistor includes an oxide semiconductor.

14. A method of driving an organic light emitting display device including a pixel providing a driving current to an organic light emitting diode according to an applied data voltage, the method comprising:
applying a data voltage to a first node;
providing the driving current to the organic light emitting diode according to the applied data voltage;
providing a preset voltage to the first node; and
while the applied data voltage is remained and the driving current is not provided to the organic light emitting diode, providing the preset voltage to the first node,

Assignees

• Lg Display Co Ltd

Inventors

• Lee Botaek
• Bong Junho

Classifications

• G09G3/3291 Primary

  in which the data driver supplies a variable data voltage for setting the current through, or the voltage across, the light-emitting elements · CPC title

• G09G2310/0272

  Details of drivers for data electrodes, the drivers communicating data to the pixels by means of a current · CPC title

• G09G3/3233 Primary

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

• G09G2320/02

  Improving the quality of display appearance · CPC title

• G09G2310/08

  Details of timing specific for flat panels, other than clock recovery · CPC title