Display device and driving method thereof

Patent metadata

Field	Value
Publication number	US-10769999-B2
Application number	US-201815989634-A
Country	US
Kind code	B2
Filing date	May 25, 2018
Priority date	Oct 16, 2017
Publication date	Sep 8, 2020
Grant date	Sep 8, 2020

Abstract

A display device includes first and second initialization voltage sources and first and second pixel circuits. The first initialization voltage source provides a first initialization voltage. The second initialization voltage source provides a second initialization voltage less than the first initialization voltage. The first pixel circuit includes a first organic light emitting diode. The second pixel circuit includes a second organic light emitting diode with an organic material having a band gap different from a band gap of an organic material in the first organic light emitting diode. The first pixel circuit is coupled to the first initialization voltage source and the second initialization voltage source. The second pixel circuit is coupled to a single initialization voltage source.

First claim

What is claimed is:

1. A display device, comprising:
a first initialization voltage source to provide a first initialization voltage;
a second initialization voltage source to provide a second initialization voltage less than the first initialization voltage;
a first pixel circuit including a first organic light emitting diode and a first driving transistor; and
a second pixel circuit including a second organic light emitting diode that includes an organic material having a band gap different from a band gap of an organic material in the first organic light emitting diode, wherein
the first pixel circuit is coupled to the first initialization voltage source and the second initialization voltage source,
the first initialization voltage is applied to a gate terminal of the first driving transistor,
the second initialization voltage is applied to an anode of the first organic light emitting diode, and
the second pixel circuit is coupled to a single initialization voltage source.

2. The display device as claimed in claim 1 , wherein the second organic light emitting diode has a greater capacitance per unit area than the first organic light emitting diode.

3. The display device as claimed in claim 1 , wherein an area of a light emitting surface of the second organic light emitting diode is less than an area of a light emitting surface of the first organic light emitting diode.

4. The display device as claimed in claim 1 , wherein the single initialization voltage source is the first initialization voltage source.

5. The display device as claimed in claim 4 , wherein:
the first driving transistor has an end coupled to the anode of the first organic light emitting diode in an emission period,
the second pixel circuit includes a second driving transistor having an end coupled to an anode of the second organic light emitting diode in an emission period, and
the first initialization voltage source is coupled to the gate terminal of the first driving transistor and a gate terminal of the second driving transistor in a first initialization period.

6. The display device as claimed in claim 5 , wherein:
the second initialization voltage source is coupled to the anode of the first organic light emitting diode in a second initialization period, and
the first initialization voltage source is coupled to the anode of the second organic light emitting diode in the second initialization period.

7. The display device as claimed in claim 1 , wherein the single initialization voltage source is the second initialization voltage source.

8. The display device as claimed in claim 7 , wherein the second initialization voltage source is coupled to the anode of the first organic light emitting diode and an anode of the second organic light emitting diode in a second initialization period that follows a first initialization period.

9. The display device as claimed in claim 8 , wherein:
the first pixel circuit includes the first driving transistor having an end coupled to the anode of the first organic light emitting diode in an emission period,
the second pixel circuit includes a second driving transistor having an end coupled to the anode of the second organic light emitting diode in an emission period,
the first initialization voltage source is coupled to the gate terminal of the first driving transistor in the first initialization period, and
the second initialization voltage source is coupled to a gate terminal of the second driving transistor in the first initialization period.

10. The display device as claimed in claim 9 , wherein the first initialization period is before the second initialization period.

11. The display device as claimed in claim 1 , further comprising:
a third initialization voltage source to provide a third initialization voltage having a voltage value different from voltage values of the first initialization voltage and the second initialization voltage, wherein
the single initialization voltage source is the third initialization voltage source.

12. The display device as claimed in claim 11 , wherein the third initialization voltage has a value between the first initialization voltage and the second initialization voltage.

13. The display device as claimed in claim 12 , wherein:
the second initialization voltage source is coupled to the anode of the first organic light emitting diode in a second initialization period, and
the third initialization voltage source is coupled to an anode of the second organic light emitting diode in the second initialization period.

14. The display device as claimed in claim 13 , wherein:
the first pixel circuit includes the first driving transistor having an end coupled to the anode of the first organic light emitting diode in an emission period,
the second pixel circuit includes a second driving transistor having an end coupled to the anode of the second organic light emitting diode in an emission period,
the first initialization voltage source is coupled to the gate terminal of the first driving transistor in a first initialization period, and
the third initialization voltage source is coupled to a gate terminal of the second driving transistor in the first initialization period.

15. The display device as claimed in claim 1 , further comprising:
a third pixel circuit coupled the first initialization voltage source and the second initialization voltage source, the third pixel circuit including a third organic light emitting diode including an organic material having a band gap different from bang gaps of the organic materials in the first organic light emitting diode and the second organic light emitting diode;
a first data line; and
a second data line different from the first data line, wherein the first pixel circuit and the third pixel circuit are coupled to the first data line and wherein the second pixel circuit is coupled to the second data line.

16. The display device as claimed in claim 15 , wherein:
the first organic light emitting diode is a red organic light emitting diode,
the second organic light emitting diode is a green organic light emitting diode, and
the third organic light emitting diode is a blue organic light emitting diode.

17. The display device as claimed in claim 15 , wherein:
the first organic light emitting diode is a red organic light emitting diode,
the second organic light emitting diode is a blue organic light emitting diode, and
the third organic light emitting diode is a green organic light emitting diode.

18. The display device as claimed in claim 15 , wherein:
the first organic light emitting diode is a blue organic light emitting diode,
the second organic light emitting diode is a red organic light emitting diode, and
the third organic light emitting diode is a green organic light emitting diode.

19. The display device as claimed in claim 15 , wherein:
the third pixel circuit includes a third driving transistor having an end coupled to an anode of the third organic light emitting diode in an emission period,
the first initialization voltage source is coupled to a gate terminal of the third driving transistor in a first initialization period, and
the second initialization voltage source is coupled to the anode of the third organic light emitting diode in a second initialization period.

20. A method for driving a display device, the method comprising:
in a first initialization period, applying a first initialization voltage to a gate terminal of a first driving transistor of a first pixel circ

Assignees

• Samsung Display Co Ltd

Inventors

• Park Hyung Jun
• Kim Yang Wan
• Kim Byung Sun
• Lee Su Jin
• Lee Jae Yong

Classifications

• G09G2310/08

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

• G09G2310/061

  for resetting or blanking · CPC title

• G09G2300/0809

  Several active elements per pixel in active matrix panels · CPC title

• G09G2300/0426

  Layout of electrodes and connections · CPC title

• G09G3/3233 Primary

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