Display device and driving method thereof

• US 10,467,958 B2
• Filed: 08/18/2017
• Issued: 11/05/2019
• Est. Priority Date: 09/09/2016
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Inventors: Kim, Yang Wan, Kwon, Sun Ja, Kim, Byung Sun, Park, Hyun Ae, Park, Hyung Jun, Lee, Su Jin, Lee, Jae Yong, Jeon, Yu Jin
• Primary Examiner(s): Pardo, Thuy N
• Application Number:
  US15/680,522
• Publication Number:
  US 20180075804A1
• Time in Patent Office: 809 Days
• Field of Search: 345211, 345 99, 345 80, 345691, 345690, 345694, 345 76, 345213, 345215, 315294
• CPC Class Codes: G09G 2300/0439 Pixel structures
• 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 2320/0223 Compensation for problems related to R-C delay and attenuation in electrodes of matrix panels, e.g. in gate electrodes or on-substrate video signal electrodes
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 2330/02 Details of power systems and of start or stop of display operation
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element

Abstract

A display device includes a first pixel area having first pixels and a second pixel area having second pixels. Each first pixel includes a driving transistor initialized to a voltage of a first initialization power supply. Each second pixel includes a driving transistor initialized to a voltage of a second initialization power supply. The first initialization power supply and the second initialization power supply are set to different voltages. The first pixel area and the second pixel area have different widths.

Claims

1. A display device comprising:

a first pixel area comprising first pixels, wherein each first pixel comprises a first driving transistor initialized to a voltage of a first initialization power supply; and

a second pixel area comprising second pixels, wherein each second pixel comprises a second driving transistor initialized to a voltage of a second initialization power supply,

wherein the first initialization power supply and the second initialization power supply are set to different voltages, and

wherein the first pixel area and the second pixel area have different widths.

2. The display device of claim 1, wherein the first pixels receive the voltage of the first initialization power supply and the second pixels receive the voltage of the second initialization power supply from a same power supply line.

3. The display device of claim 2, wherein

the voltage of the first initialization power supply is supplied to the power supply line during a period in which the first driving transistors are initialized, and

the voltage of the second initialization power supply is supplied to the power supply line during a period in which the second driving transistors are initialized.

4. The display device of claim 2, wherein the power supply line is positioned at one side of each of the first pixel area and the second pixel area.

5. The display device of claim 2, wherein the power supply line is positioned at opposite sides while interposing the first pixel area and the second pixel area therebetween.

6. The display device of claim 1, wherein

the first pixels receive the first initialization power supply from a first power supply line, and

the second pixels receive the second initialization power supply from a second power supply line.

7. The display device of claim 6, wherein

the first power supply line is positioned at one side of the first pixel area, and

the second power supply line is positioned at one side of the second pixel area.

8. The display device of claim 6, wherein

the first power supply line is positioned at opposite sides while interposing the first pixel area therebetween, and

the second power supply line is positioned at opposite sides while interposing the second pixel area therebetween.

9. The display device of claim 6, wherein

the first power supply line is positioned at one side of the first pixel area, and

the second power supply line is positioned at opposite sides while interposing the second pixel area therebetween.

10. The display device of claim 1, wherein the first pixel area has a wider width than the second pixel area.

11. The display device of claim 10, wherein each of the first pixels and the second pixels comprises:

an organic light emitting diode (OLED); and

a control transistor connected between the OLED and a node receiving the first initialization power supply or between the OLED and the node receiving the second initialization power supply.

12. The display device of claim 11, wherein the first initialization power supply is set to a lower voltage than the second initialization power supply.

13. The display device of claim 11, wherein

the first pixels and the second pixels receive the first initialization power supply and the second initialization power supply from a same power supply line, and

supply timings of the first initialization power supply and the second initialization power supply are set by a scan signal that is supplied to the first pixel area and the second pixel area.

14. The display device of claim 13, wherein

the scan signal is sequentially supplied to the second pixel area and then to the first pixel area,

a voltage of the second initialization power supply is supplied to the power supply line during a period in which the scan signal is supplied to at least part of the second pixel area, and

a voltage of the first initialization power supply is supplied to the power supply line from a time point when the last scan signal is supplied to the second pixel area.

15. The display device of claim 10, wherein the second pixel area has a width that gradually decreases from a first width to a second width that is smaller than the first width.

16. The display device of claim 15, wherein the second pixel area is divided into a plurality of regions including at least one horizontal line.

17. The display device of claim 16, wherein the second initialization power supply is set to different voltages in each of the regions.

18. The display device of claim 10, further comprising:

a third pixel area comprising a plurality of third pixels,

wherein the third pixel area has the same width as the second pixel area, and

wherein each third pixel comprises a third driving transistor initialized to a voltage of the second initialization power supply.

19. The display device of claim 18, wherein the second pixel area is positioned in an upper part of the first pixel area at one side thereof, and the third pixel area is positioned in a lower part of the first pixel area at one side thereof.

20. The display device of claim 18, wherein the first pixels, the second pixels, and the third pixels receive voltages of the first initialization power supply and the second initialization power supply from a same power supply line.

21. The display device of claim 18, wherein

the first pixels receive a voltage of the first initialization power supply from a first power supply line, and

the second pixels and the third pixels receive a voltage of the second initialization power supply from a second power supply line.

22. The display device of claim 10, further comprising

a third pixel area comprising third pixels,

wherein a width of the third pixel area is different from that of the second pixel area, and

wherein each third pixel comprises a third driving transistor initialized to a voltage of a third initialization power supply that is different from those of the first initialization power supply and the second initialization power supply.

23. The display device of claim 22, wherein the second pixel area is positioned in an upper part of the first pixel area at one side thereof, and the third pixel area is positioned in a lower part of the first pixel area at one side thereof.

24. The display device of claim 22, wherein the first pixels, the second pixels, and the third pixels receive voltages of the first initialization power supply, the second initialization power supply, and the third initialization power supply from a same power supply line.

25. The display device of claim 22, wherein

the first pixels receive a voltage of the first initialization power supply from a first power supply line,

the second pixels receive a voltage of the second initialization power supply from a second power supply line, and

the third pixels receive a voltage of the third initialization power supply from a third power supply line.

26. A driving method of a display device, comprising:

supplying a voltage of a first initialization power supply to first pixels positioned in a first pixel area of the display device; and

supplying a voltage of a second initialization power supply to second pixels positioned in a second pixel area of the display device,

wherein the first initialization power supply is different from the second initialization power supply,

wherein the voltage of the first initialization power supply and the voltage of the second initialization power supply are set to minimize a luminance difference between the first pixels and the second pixels,

wherein the first initialization power supply is supplied to a gate electrode of a first driving transistor included in each first pixel, and the second initialization power supply is supplied to a gate electrode of a second driving transistor included in each second pixel, and

wherein the first and second pixel areas have different widths.

27. The driving method of claim 26, wherein the first initialization power supply and the second initialization power supply are supplied to the first pixels and the second pixels by a same power supply line.

28. The driving method of claim 27, wherein the first initialization power supply and the second initialization power supply are supplied to the power supply line at different times.

29. The driving method of claim 26, wherein the first initialization power supply is supplied to the first pixels by a first power supply line, and the second initialization power supply is supplied to the second pixels by a second power supply line.

30. A display device comprising:

a first pixel area comprising first pixels, wherein each first pixel comprises a first driving transistor initialized to a voltage of a first initialization power supply; and

a second pixel area comprising second pixels, wherein each second pixel comprises a second driving transistor initialized to a voltage of a second initialization power supply,

wherein the first initialization power supply and the second initialization power supply are set to different voltages, and

wherein the first pixel area has a rectangular shape and the second pixel area has a trapezoidal shape.

31. The display device of claim 30, wherein each row of the first pixel area includes a same number of the first pixels and a first row of the second pixel area includes a lesser number of the second pixels than a second row of the second pixel area.

32. The display device of claim 30, wherein

each first pixel includes a first control transistor and a first organic light emitting diode (OLED), a first node of the first control transistor connected to the first OLED, and a second node of the first control transistor receives the first initialization power supply,

each second pixel includes a second control transistor and a second organic emitting diode (OLED), a first node of the second control transistor connected to the second OLED, and a second node of the second control transistor receives the second initialization power supply.