ORGANIC LIGHT-EMITTING DISPLAY DEVICE AND METHOD OF DRIVING THE SAME

• US 20160148571A1
• Filed: 05/04/2015
• Published: 05/26/2016
• Est. Priority Date: 11/24/2014
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Inventors: Hwang, Young In, Cho, Young Jin
• Granted Patent: US 9,685,118 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G09G 2310/0262 The addressing of the pixel, in a display other than an active matrix LCD, involving the control of two or more scan electrodes or two or more data electrodes, e.g. pixel voltage dependent on signals of two data electrodes
• CPC Class Codes: G09G 2310/08 Details of timing specific for flat panels, other than clock recovery
• CPC Class Codes: G09G 2320/043 Preventing or counteracting the effects of ageing
• CPC Class Codes: G09G 3/3225 using an active matrix
• CPC Class Codes: G09G 3/3266 Details of drivers for scan electrodes

Abstract

An organic light-emitting display device includes a data line, a scan line, and a display panel including a pixel where the data line crosses the scan line. The pixel includes: a switching transistor including a gate electrode connected to the scan line and a first electrode connected to the data line; a first capacitor between a second electrode of the switching transistor and a reference voltage source; a second capacitor including a first terminal connected to the first electrode of the switching transistor via a first node and a second terminal connected to a second node; a driving transistor including a first electrode connected to a first power source via the second node, a second electrode connected to an organic light-emitting diode, and a gate electrode connected to the reference voltage source via a third node; and a third capacitor between the second and third nodes.

Claims

1. An organic light-emitting display device comprising:

a data driver configured to provide a data signal to a data line;

a scan driver configured to provide a scan signal to a scan line; and

a display panel comprising at least one pixel at a crossing region of the data line and the scan line, the at least one pixel comprising;

a switching transistor comprising a gate electrode connected to the scan line and a first electrode connected to the data line;

a first capacitor comprising a first terminal connected to a second electrode of the switching transistor and a second terminal connected to a reference voltage source;

a second capacitor comprising a first terminal connected to the first electrode of the switching transistor via a first node and a second terminal connected to a second node;

a driving transistor comprising a first electrode connected to a first power source via the second node, a second electrode connected to an organic light-emitting diode (OLED), and a gate electrode connected to the reference voltage source via a third node; and

a third capacitor comprising a first terminal connected to the second node and a second terminal connected to the third node.

2. The organic light-emitting display device of claim 1, wherein the at least one pixel further comprises:

a first transistor comprising a first electrode connected to the second electrode of the switching transistor and a second electrode connected to the first node;

a second transistor comprising a first electrode connected to the reference voltage source and a second electrode connected to the first node;

a switching unit connected between the reference voltage source and the third node;

a third transistor comprising a first electrode connected to the first power source and a second electrode connected to the second node;

a fourth transistor comprising a first electrode connected to the second electrode of the driving transistor and a second electrode connected to the OLED; and

a fifth transistor comprising a first electrode connected to the first electrode of the fourth transistor and a second electrode connected to a gate electrode of the fifth transistor.

3. The organic light-emitting display device of claim 2, wherein the switching unit comprises sixth and seventh transistors, each constituting a separate path between the reference voltage source and the third node.

4. The organic light-emitting display device of claim 3, wherein the second, fifth and sixth transistors are configured to turn on during a first period of a compensation period, the first and seventh transistors are configured to turn on during a second period of the compensation period, which follows the first period, and the third and fourth transistors are configured to turn on during an emission period, which follows the second period.

5. The organic light-emitting display device of claim 2, wherein the switching unit comprises an eighth transistor comprising a first electrode connected to the reference voltage source and a second electrode connected to the third node.

6. The organic light-emitting display device of claim 1, wherein the driving transistor is configured to control a driving current flowing through the OLED by using a data voltage that depends on a voltage charged in each of the first through third capacitors as well as a voltage provided by the first power source via the second node.

7. An organic light-emitting display device comprising:

a data driver configured to provide a data signal to a data line;

a scan driver configured to provide a scan signal to a scan line; and

a display panel comprising at least one pixel at a crossing region of the data line and the scan line, the at least one pixel comprising;

a data voltage providing unit configured to charge a first capacitor with a data voltage provided via the data line and apply the data voltage that the first. capacitor is charged with to a first node via a switching operation;

a second capacitor comprising a first terminal connected to the first node and a second terminal connected to a second node;

a driving transistor configured to control a driving current flowing through an organic light-emitting diode (OLED) according to a voltage applied to the second node and a voltage applied to a third node that is connected to a gate electrode of the driving transistor;

a reference voltage providing unit configured to apply a reference voltage to the third node;

a third capacitor comprising a first terminal connected to the second node and a second terminal connected to the third node, and configured to be charged with the reference voltage;

a first switching unit configured to connect or block a path between a first power source and the second node; and

a second switching unit configured to connect or block a path between a second electrode of the driving transistor and the OLED.

8. The organic light-emitting display device of claim 7, wherein the data voltage providing unit comprises:

a switching transistor comprising a first electrode connected to the data line and a gate electrode connected to the scan line;

a first transistor comprising a first electrode connected to a second electrode of the switching transistor and a second electrode connected to the first node; and

a second transistor comprising a first electrode connected to a second terminal of the first capacitor and a second electrode connected to the first node.

9. The organic light-emitting display device of claim 7, wherein the first switching unit comprises a third transistor comprising a first electrode connected to the first power source and a second electrode connected to the second node.

10. The organic light-emitting display device of claim 7, wherein the second switching unit comprises:

a fourth transistor comprising a first electrode connected to the second electrode of the driving transistor and a second electrode connected to the OLED; and

a fifth transistor comprising a first electrode connected to the first electrode of the fourth transistor and a second electrode connected to a gate electrode of the fifth transistor.

11. The organic light-emitting display device of claim 7, wherein the reference voltage providing unit comprises sixth and seventh transistors, each constituting a separate path between a source of the reference voltage and the third node.

12. The organic light-emitting display device of claim 7, wherein the reference voltage providing unit comprises an eighth transistor comprising a first electrode connected to a source of the reference voltage and a second electrode connected to the third node.

13. The organic light-emitting display device of claim 7, wherein the driving transistor is configured to control the driving current flowing through the OLED by using a data voltage that depends on a voltage charged in each of the first through third capacitors as well as a voltage provided by the first power source via the second node.

14. The organic light-emitting display device of claim 7, wherein

the data voltage providing unit is configured to apply the reference voltage to the first node during a first period of a compensation period and apply the data voltage to the first node during a second period of the compensation period, which follows the first period, and

the reference voltage providing unit is configured to apply the reference voltage to the third node during the first and second periods.

15. The organic light-emitting display device of claim 14, wherein

the first switching unit is configured to block a path between the first power source and the second node during the first and second periods and to connect the path between the first power source and the second node during an emission period, which follows the second period, and

the second switching unit is configured to block a path between the second electrode of the driving transistor and the OLED during the first and second periods and to connect the path between the second electrode of the driving transistor and the OLED during the emission period.

16. A method of driving an organic light-emitting display device comprising at least one pixel, the at least one pixel comprising a driving transistor connected between a first power source and a second power source and configured to control a driving current flowing through an OLED, a switching transistor connected to a data line, and a first capacitor connected between the switching transistor and a reference voltage source, the method comprising:

applying a reference voltage provided by the reference voltage source to a first node and a gate electrode of the driving transistor during a first period of a compensation period;

applying a data voltage that the first capacitor is charged with to a first electrode of the driving transistor through a switching operation during a second period of the compensation period that follows the first period; and

applying the data voltage to the gate electrode of the driving transistor by connecting a path between the first power source and the second power source during an emission period.

17. The method of claim 16, wherein the at least one pixel comprises:

a first switching unit configured to connect or block a path between the first power source and a second node; and

a second switching unit configured to connect or block a path between a second electrode of the driving transistor and the OLED.

18. The method of claim 17, wherein

during the first and second periods, the first switching unit is configured to block the path between the first power source and the second node, and the second switching unit is configured to block the path between the second electrode of the driving transistor and the OLED, and

during the emission period, the first switching unit is configured to connect the path between the first power source and the second node, and the second switching unit is configured to connect the path between the second electrode of the driving transistor and the OLED.

19. The method of claim 16, wherein the at least one pixel further comprises:

a second capacitor comprising a first terminal connected to the first node and a second terminal connected to the first electrode of the driving transistor; and

a third capacitor comprising a first terminal connected to the first electrode of the driving transistor and a second terminal connected to the gate electrode of the driving transistor.

20. The method of claim 19, wherein

the data voltage depends on a voltage charged in each of the first through third capacitors as well as a driving voltage provided by the first power source, and

the driving transistor is configured to control the driving current flowing through the OLED according to the data voltage.