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

• US 20160321995A1
• Filed: 04/27/2016
• Published: 11/03/2016
• Est. Priority Date: 04/28/2015
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Inventors: Shin, Hwang Sup
• Granted Patent: US 9,916,789 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G09G 2300/0426 Layout of electrodes and connections
• CPC Class Codes: G09G 2300/0861 with additional control of the display period without amending the charge stored in a pixel memory, e.g. by means of additional select electrodes
• CPC Class Codes: G09G 2310/0251 Precharge or discharge of pixel before applying new pixel voltage
• 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 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element
• CPC Class Codes: G09G 3/3258 with pixel circuitry controlling the voltage across the light-emitting element
• CPC Class Codes: G09G 3/3266 Details of drivers for scan electrodes
• CPC Class Codes: G09G 3/3275 Details of drivers for data electrodes
• CPC Class Codes: H10K 59/1213 the pixel elements being TFTs
• CPC Class Codes: H10K 59/1216 the pixel elements being capacitors
• CPC Class Codes: H10K 59/123 Connection of the pixel electrodes to the thin film transistors [TFT]
• CPC Class Codes: H10K 59/131 Interconnections, e.g. wiring lines or terminals

Abstract

An organic light-emitting diode display and a method of driving the same are disclosed. In one aspect, the display includes a light emission control line configured to provide a light emission control signal and a power line configured to provide a power voltage. An operation control TFT is electrically connected to the power line and configured to be turned on based on the light emission control signal so as to provide the power voltage. A driving TFT is electrically connected to the operation control TFT, an OLED is electrically connected to the driving TFT, and an initialization TFT is configured to provide the power voltage to the driving TFT. In a frame of the OLED display, the power voltage provided when the initialization TFT is turned on and the power voltage provided when the operation control TFT is turned on are different from each other.

Claims

1. An organic light-emitting diode (OLED) display. comprising:

a substrate;

a scan line formed over the substrate and configured to provide a scan signal;

an initialization line formed over the substrate and configured to provide an initialization signal;

a light emission control line formed over the substrate and configured to provide a light emission control signal;

a data line crossing the scan line and configured to provide a data signal;

a power line crossing the scan line and configured to provide a power voltage;

a switching thin film transistor (TFT) electrically connected to the scan line and the data line;

a driving thin film transistor electrically connected to a drain electrode of the switching thin film transistor;

an OLED electrically connected to a drain electrode of the driving thin film transistor;

an initialization thin film transistor configured to be turned on based on the initialization signal provided through the initialization line so as to apply the power voltage to a gate electrode of the driving thin film transistor; and

an operation control thin film transistor configured to be turned on based on the light emission control signal provided through the light emission control line so as to apply the power voltage to the driving thin film transistor,

wherein, in one frame, the power voltage when the initialization thin film transistor is turned on and the power voltage when the operation control thin film transistor is turned on are different from each other.

2. The OLED display of claim 1, wherein the power line includes a first line electrically connected to the initialization thin film transistor and a second line electrically connected to the operation control thin film transistor, and wherein the first line and the second line cross each other and are connected to each other through a contact hole.

3. The OLED display of claim 2, further comprising a compensation thin film transistor electrically connected to the driving thin film transistor and configured to compensate a threshold voltage of the driving thin film transistor.

4. The OLED display of claim 3, further comprising a light emission control thin film transistor configured to be turned on based on the light emission control signal provided through the light emission control line so as to provide the power voltage from the driving thin film transistor to the OLED, wherein the light emission control thin film transistor is interposed between the drain of the driving thin film transistor and the OLED.

5. The OLED display of claim 4, further comprising:

a reset line formed over the substrate and configured to provide a reset signal; and

a reset thin film transistor configured to be turned on based on the reset signal provided through the reset line so as to apply the power voltage to an anode of the OLED.

6. The OLED display of claim 5, wherein the reset transistor is electrically connected to the initialization transistor and the first line.

7. The OLED display of claim 6, wherein the initialization thin film transistor and the reset thin film transistor are further configured to be concurrently turned on.

8. The OLED display of claim 7, further comprising a storage capacitor including a first end electrically connected to the power line and a second end electrically connected to the gate of the driving thin film transistor.

9. The OLED display of claim 1, wherein the polarity of the power voltage when the initialization thin film transistor is turned on and the polarity of the power voltage when the operation control thin film transistor is turned on are opposite to each other.

10. A method of driving an organic light-emitting diode (OLED) display including a display unit including a plurality of pixels and a power supply configured to supply a power voltage to the pixels, the driving method comprising:

changing the power voltage to a low-level power voltage;

applying an enable-level initialization signal to the pixels; and

changing the power voltage to a high-level power voltage.

11. The method of claim 10, further comprising writing a data signal to the pixels after changing the power voltage to the high-level power voltage.

12. The method of claim 11, further comprising applying an enable-level light emission control signal to the pixels after the writing of the data signal to the pixels.

13. The method of claim 12, wherein the pixels includes an initialization thin film transistor configured to be turned on based on the initialization signal and a driving thin film transistor configured to supply a driving current to the OLED, and wherein the applying of the enable level initialization signal to the pixel includes applying the low-level power voltage to a gate of the driving thin film transistor.

14. The method of claim 13, further comprising applying an enable-level reset signal to the pixels.

15. The method of claim 14, wherein the pixel includes a reset thin film transistor configured to be turned on based on the reset signal, and wherein the applying of the enable-level reset signal to the pixel includes applying the low-level power voltage to an anode of the OLED.

16. The method of claim 15, wherein the applying of the enable-level initialization signal to the pixel and the applying of the enable-level reset signal to the pixel are concurrently performed.

17. An organic light-emitting diode (OLED) display, comprising:

a light emission control line configured to provide a light emission control signal;

a power line crossing the light emission control line and configured to provide a power voltage;

an operation control thin film transistor (TFT) electrically connected to the power line and configured to be turned on based on the light emission control signal so as to provide the power voltage;

a driving TFT electrically connected to the operation control TFT;

an OLED electrically connected to the driving TFT; and

an initialization TFT configured to provide the power voltage to the driving TFT,

wherein, in a frame of the OLED display, the power voltage provided when the initialization TFT is turned on and the power voltage provided when the operation control TFT is turned on are different from each other.

18. The OLED display of claim 17, further comprising a reset TFT configured to turn on based on a reset signal, wherein the frame includes an initialization period when the reset signal, the initialization signal and the power voltage have an ON voltage level, and wherein the period in which reset signal and the initialization signal have the ON voltage level is less than the period in which the power voltage has the ON voltage level during the initialization period.

19. The OLED display of claim 18, further comprising a switching TFT configured to receive a data signal and provide the data signal based on a scan signal, and wherein the operation control TFT, the driving TFT and switching TFT are directly connected to each other.

20. The OLED display of claim 19, wherein a polarity of the power voltage when the initialization TFT is turned on and the polarity of the power voltage when the operation control TFT is turned on are opposite to each other.