Organic light-emitting diode display capable of reducing kickback effect

Patent metadata

Field	Value
Publication number	US-10930210-B2
Application number	US-201715472503-A
Country	US
Kind code	B2
Filing date	Mar 29, 2017
Priority date	Mar 29, 2016
Publication date	Feb 23, 2021
Grant date	Feb 23, 2021

Abstract

An OLED display includes a plurality of pixel lines each connected to a plurality of pixels, the plurality of pixel lines including at least two adjacent pixel lines, each pixel including a driving TFT, a first switching TFT, a second switching TFT, and an emission control TFT connected to the driving TFT. The OLED display also includes a first scan driver controlling the first switching TFTs for the two pixel lines. The OLED display also includes a second scan driver controlling the second switching TFTs for the two pixel lines. The OLED display also includes a third scan driver configured so that all of the emission control TFTs for the two pixel lines are turned on in a programming period, maintain a turn-on state for a portion of an emission period, and can adjust an on-time duty of the emission period after the portion of time.

First claim

What is claimed is:

1. An organic light-emitting diode (OLED) display, comprising:
a plurality of pixel lines each connected to a plurality of pixels, the plurality of pixel lines including at least an n th pixel line and an (n+1) th pixel line, where n is a natural number, each pixel including:
a driving thin film transistor (TFT);
a first switching TFT connected to the driving TFT;
a second switching TFT connected to the driving TFT; and
an emission control TFT connected to the driving TFT;

a first scan driver configured to control the first switching TFTs included in pixels corresponding to the n th pixel line and the (n+1) th pixel line;
a second scan driver configured to control the second switching TFTs included in the pixels corresponding to the n th pixel line and the (n+1) th pixel line; and
a third scan driver configured such that all of the emission control TFTs included in the pixels corresponding to the n th pixel line and the (n+1) th pixel line:
are turned on in a programming period;
maintain a turn-on state for a portion of time of an emission period following the programming period; and

are able to adjust an on-time duty of the emission period after the portion of time,
wherein an emission control signal of the third scan driver maintains the turn-on state for the particular portion of time after both the first switching TFT and the second switching TFT are turned off, and then be turned off to reduce kickback.

2. The organic light-emitting diode display of claim 1 , wherein:
the n th pixel line and the (n+1) th pixel line are configured to operate at a same on-time duty of the emission period by the third scan driver;
the first scan driver includes a plurality of stages configured to drive the n th pixel line and the (n+1) th pixel line;
the second scan driver includes a plurality of stages configured to drive the n th pixel line and the (n+1) th pixel line; and
the third scan driver includes a plurality of stages configured to drive the n th pixel line and the (n+1) th pixel line.

3. The organic light-emitting diode display of claim 2 , wherein one of the plurality of stages of the third scan driver is configured to simultaneously drive the n th pixel line and the (n+1) th pixel line.

4. The organic light-emitting diode display of claim 3 , further comprising a third gate line connecting the emission control TFTs of the n th pixel line and the (n+1) th pixel line to a corresponding stage of the third scan driver.

5. The organic light-emitting diode display of claim 3 , wherein the third scan driver is configured to simultaneously apply an emission control signal corresponding to the programming period and the emission period to the emission control TFTs of the n th pixel line and the (n+1) th pixel line.

6. The organic light-emitting diode display of claim 2 , wherein each of the plurality of stages of the first scan driver is configured to respectively drive the plurality of pixel lines corresponding to the plurality of stages.

7. The organic light-emitting diode display of claim 6 , further comprising a plurality of first gate lines connecting the first switching TFTs of the n th pixel line and the (n+1) th pixel line to a corresponding stage of the first scan driver.

8. The organic light-emitting diode display of claim 6 , wherein the first scan driver is configured to sequentially apply first scan control signals corresponding to the programming period and the emission period to the first switching TFTs of the n th pixel line and the (n+1) th pixel line.

9. The organic light-emitting diode display of claim 2 , wherein one of the plurality of stages of the second scan driver is configured to simultaneously drive the n th pixel line and the (n+1) th pixel line.

10. The organic light-emitting diode display of claim 9 , further comprising a second gate line connecting the second switching TFTs of the n th pixel line and the (n+1) th pixel line to a corresponding stage of the second scan driver.

11. The organic light-emitting diode display of claim 9 , wherein the second scan driver is configured to simultaneously apply a second scan control signal corresponding to the programming period and the emission period to the second switching TFTs of the n th pixel line and the (n+1) th pixel line.

12. The organic light-emitting diode display of claim 2 , wherein each of the plurality of stages of the second scan driver is configured to respectively drive the plurality of pixel lines corresponding to the plurality of stages.

13. The organic light-emitting diode display of claim 12 , further comprising a plurality of second gate lines connecting the second switching TFTs of the n th pixel line and the (n+1) th pixel line to a corresponding stage of the second scan driver.

14. The organic light-emitting diode display of claim 12 , wherein a data voltage applied to the n th pixel line and the (n+1) th pixel line implements an inverse gamma gray level.

15. An organic light-emitting diode (OLED) display including a programming period and an emission period, comprising:
a first switching TFT between a gate node of a driving thin film transistor (TFT) and a data line, the first switching TFT being configured to supply a data voltage to the gate node in the programming period;
a second switching TFT between a source node of the driving TFT and a reference line, the second switching TFT being configured to bypass a transient current, that is supplied through the driving TFT, to the reference line in the programming period;
an emission control TFT between a drain node of the driving TFT and a high potential driving voltage supply line, the emission control TFT being configured to supply a high potential driving voltage to the drain node in the programming period;
a storage capacitor between the gate node and the source node, the storage capacitor being configured to charge a gate node-to-source node voltage of the driving TFT in the programming period; and
an organic light-emitting diode connected to the source node, the OLED being configured to maintain a non-emission state in the programming period,
wherein the emission control TFT is further configured to:
be turned on during the programming period,
maintain a turn-on state for a portion of time of the emission period, and
adjust an on-time duty of the emission period after the portion of time, and

wherein the emission control TFT maintains the turn-on state for the particular portion of time after both the first switching TFT and the second switching TFT are turned off, and then be turned off to reduce kickback.

16. The organic light-emitting diode display of claim 15 , wherein the drain node is not in a floating state in the programming period, and is not in a floating state for the portion of time of the emission period to reduce kickback.

17. The organic light-emitting diode display of claim 15 , wherein, in the emission period, the emission control TFT maintains a turn-off state for a particular time from the portion of time and then is turned on.

18. The organic light-emitting diode display of claim 17 , wherein, in the emission period, the emission control TFT operates in a pulse duty drive in which a variable duty is adjustable.

Assignees

• Lg Display Co Ltd

Inventors

• Lee Hyunsuk
• Kwon Junyoung
• Jin Seungtae

Classifications

• G09G2310/0251

  Precharge or discharge of pixel before applying new pixel voltage · CPC title

• G09G2320/0693

  Calibration of display systems · CPC title

• G09G2320/0295

  by monitoring each display pixel · CPC title

• G09G2310/0262

  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 title

• G09G2300/0861

  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 title